193 results on '"Cook TA"'
Search Results
2. PWE-298 Ct usage for the detection of post-operative colorectal complications: impact on radiological and surgical services
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Florance, CJ, Francis, R, Kynaston, J, and Cook, TA
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- 2015
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3. A 3-year multi-institutional experience with the liposhaver
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Kreit Jd, Park Ss, Gross Cw, Wang Td, Daniel G. Becker, Tardy Me, and Cook Ta
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Male ,medicine.medical_specialty ,Esthetics ,medicine.medical_treatment ,Preoperative care ,Hematoma ,Patient satisfaction ,Lipectomy ,Platysma muscle ,medicine ,Humans ,Surgery, Plastic ,Equipment Safety ,business.industry ,General Medicine ,Equipment Design ,medicine.disease ,Surgery ,Clinical trial ,Pulmonary aspiration ,Treatment Outcome ,Patient Satisfaction ,Concomitant ,Liposuction ,Female ,business ,Follow-Up Studies - Abstract
Objective To report a 3-year multi-institutional clinical experience with the liposhaver in facial plastic surgery. Design Nonrandomized, nonblinded, multi-institutional evaluation of the liposhaver in a clinical setting. Interventions Seventy-two patients who presented for facial plastic surgical procedures underwent surgery with the liposhaver. Seventy-six liposhaving procedures and 74 concomitant procedures were performed. Standardized preoperative and postoperative photographs were obtained. Outcome Measure Subjective evaluation by the surgeons who performed the procedures. Results The liposhaver was used successfully in all cases. The fat was cleanly shaved and the contour results were even, without dimpling or significant asymmetry. Operative time was comparable to that of conventional liposuction. There were no cases of facial nerve injury and no evidence of increased bleeding intraoperatively. Two male patients had small postoperative hematomas in the immediate postoperative period that were successfully treated with conservative measures. An additional patient developed a small hematoma on postoperative day 5 that was effectively treated with needle aspiration and a pressure dressing. Conclusion This 3-year multi-institutional report suggests that the liposhaver continues to offer a precise alternative to conventional liposuction.
- Published
- 2000
4. Undertaking Procedure-Based Assessment is Feasible in Clinical Practice
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James, K, primary, Cross, K, additional, Lucarotti, ME, additional, Fowler, AL, additional, and Cook, TA, additional
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- 2009
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5. Correspondence
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Cook Ta, Braithwaite Bd, R.B. Galland, and Earnshaw Jj
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Medicine(all) ,medicine.medical_specialty ,business.industry ,Pulse (signal processing) ,medicine.medical_treatment ,Thrombolysis ,Peripheral ,Text mining ,Internal medicine ,Cardiology ,Medicine ,Surgery ,Cardiology and Cardiovascular Medicine ,business - Published
- 1995
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6. Differences in contractile properties of anorectal smooth muscle may permit targeted pharmacological manipulation
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Cook, TA, primary, Brading, AF, additional, and Mortensen, NJMcC, additional
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- 1998
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7. Two week rule referral for patients with colorectal cancer below the age of 50; are we being ageist?
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Shabbir J, Vijayan V, Silavant M, Fowler AL, Cook TA, Lucarotti ME, Shabbir, J, Vijayan, V, Silavant, M, Fowler, A L, Cook, T A, and Lucarotti, M E
- Abstract
Objectives: The TWR system was introduced in July 2000. The purpose of this study was to investigate whether patients below the age of 50 years with colorectal cancer (CRC) are experiencing delays in treatment.Methods: The CRC database was searched for all newly diagnosed colorectal cancers between January 2001 and December 2005 in patients who were aged less than 50 years.Results: There were 911 patients with CRC during the study period. Of these, 41 patients (4.5%) were aged under 50. Thirty-eight case notes were retrieved and reviewed; the median age was 47 years. Fourteen (37%) presented as an emergency, 9 (24%) via the TWR, 8 (21%) were non-TWR referrals to outpatients and the remainder were referred via miscellaneous routes. The median time from referral to initial consultation was 11 days (range 8-14 days) in the TWR group, 24 days (range 14-135 days) in the surgical outpatients group and 44 days (range 11-93 days) in the miscellaneous (direct endoscopy, in-hospital physician's referral) group. The median time from referral to initiation of treatment was 51 days (range 15-116 days) in the TWR group, 103 days (range 43-174 days) in the outpatient group and 96 days (range 27-270 days) in the miscellaneous group. Excluding age as a factor, 73% of the non-TWR referrals met the TWR criteria.Conclusion: Patients with symptoms of CRC below the age of 50 years may face referral and diagnostic delay if not referred via the TWR system; many of these would be eligible if age was not a deciding factor. [ABSTRACT FROM AUTHOR]- Published
- 2009
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8. The 'butterfly' graft in functional secondary rhinoplasty.
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Clark JM and Cook TA
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- 2002
9. Immediate reconstruction of extruded alloplastic nasal implants with irradiated homograft costal cartilage.
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Clark JM and Cook TA
- Published
- 2002
10. The liposhaver in facial plastic surgery. A multi-institutional experience.
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Becker DG, Weinberger MS, Miller PJ, Park SS, Wang TD, Cook TA, Tardy ME Jr, and Gross CW
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- 1996
11. Ketorolac (Toradol) and acute random-pattern skin flap survival in rat.
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Davis RE, Cohen JI, Robinson JE, Urben SL, and Cook TA
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- 1995
12. Autologous free dermal fat graft.
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Davis RE, Guida RA, and Cook TA
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- 1995
13. A comparative analysis of gene and protein expression in chronic and acute models of photoreceptor degeneration in adult zebrafish.
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Kramer AC, Carthage J, Berry Y, Gurdziel K, Cook TA, and Thummel R
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Background: Adult zebrafish are capable of photoreceptor (PR) regeneration following acute phototoxic lesion (AL). We developed a chronic low light (CLL) exposure model that more accurately reflects chronic PR degeneration observed in many human retinal diseases. Methods: Here, we characterize the morphological and transcriptomic changes associated with acute and chronic models of PR degeneration at 8 time-points over a 28-day window using immunohistochemistry and 3'mRNA-seq. Results: We first observed a differential sensitivity of rod and cone PRs to CLL. Next, we found no evidence for Müller glia (MG) gliosis or regenerative cell-cycle re-entry in the CLL model, which is in contrast to the robust gliosis and proliferative response from resident MG in the AL model. Differential responses of microglia between the models was also observed. Transcriptomic comparisons between the models revealed gene-specific networks of PR regeneration and degeneration, including genes that are activated under conditions of chronic PR stress. Finally, we showed that CLL is at least partially reversible, allowing for rod and cone outer segment outgrowth and replacement of rod cell nuclei via an apparent upregulation of the existing rod neurogenesis mechanism. Discussion: Collectively, these data provide a direct comparison of the morphological and transcriptomic PR degeneration and regeneration models in zebrafish., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kramer, Carthage, Berry, Gurdziel, Cook and Thummel.)
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- 2023
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14. Developing the Optimal Osteotome Hand-Sharpening Method.
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Nguyen TV, Park AC, Hernandez K, Ahmed KH, Vasudev M, Dilley KK, Sterritt NL, Tasman AJ, Pastorek N, Cook TA, Mo JH, and Wong BJF
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- Humans, Animals, Cattle, Osteotomy, Rhinoplasty methods, Stroke
- Abstract
Background: Rhinoplasty osteotomes can be sharpened in various ways: professional sharpening or hand sharpening using whetstones or rotary powered devices. Objective: To compare the effectiveness of sharpening osteotomes using various sharpening methods with that of professional sharpening as measured by a custom edge tester. Materials and Methods: We performed repeated serial osteotome impacts on bovine femoral cortical bone. These dull osteotomes were sharpened using preidentified sharpening techniques. Edge morphology was evaluated. Sharpness was tested using a custom mechanical testing platform. Optimized sharpness was achieved with a whetstone sharpening method wherein the osteotome is flipped after every stroke. Results: Seven distinct sharpening methods were tested for sharpness five times each to determine the optimal sharpening method versus professional sharpening (control). The two sharpening methods, 5 (5.51 ± 0.32) and 6 (5.55 ± 0.32), that used this flipping technique were significantly sharper than other methods. Methods 5 ( p = 1.0) and 6 ( p = 1.0) were the only methods that were not significantly different from control. Conclusion: Single stroke with successively alternating surfaces created the sharpest blades that achieved results similar to professional sharpening.
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- 2023
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15. Probing the conserved roles of cut in the development and function of optically different insect compound eyes.
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Rathore S, Meece M, Charlton-Perkins M, Cook TA, and Buschbeck EK
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Astonishing functional diversity exists among arthropod eyes, yet eye development relies on deeply conserved genes. This phenomenon is best understood for early events, whereas fewer investigations have focused on the influence of later transcriptional regulators on diverse eye organizations and the contribution of critical support cells, such as Semper cells (SCs). As SCs in Drosophila melanogaster secrete the lens and function as glia, they are critical components of ommatidia. Here, we perform RNAi-based knockdowns of the transcription factor cut (CUX in vertebrates), a marker of SCs, the function of which has remained untested in these cell types. To probe for the conserved roles of cut , we investigate two optically different compound eyes: the apposition optics of D. melanogaster and the superposition optics of the diving beetle Thermonectus marmoratus . In both cases, we find that multiple aspects of ocular formation are disrupted, including lens facet organization and optics as well as photoreceptor morphogenesis. Together, our findings support the possibility of a generalized role for SCs in arthropod ommatidial form and function and introduces Cut as a central player in mediating this role., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Rathore, Meece, Charlton-Perkins, Cook and Buschbeck.)
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- 2023
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16. Global Gene Expression Analysis Reveals Complex Cuticle Organization of the Tribolium Compound Eye.
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Chen Q, Sasikala-Appukuttan AK, Husain Z, Shrivastava A, Spain M, Sendler ED, Daines B, Fischer S, Chen R, Cook TA, and Friedrich M
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- Animals, Phylogeny, Gene Expression Profiling, Transcriptome, Insect Proteins genetics, Insect Proteins metabolism, RNA Interference, Tribolium genetics
- Abstract
The red flour beetle Tribolium castaneum is a resource-rich model for genomic and developmental studies. To extend previous studies on Tribolium eye development, we produced transcriptomes for normal-eyed and eye-depleted heads of pupae and adults to identify differentially transcript-enriched (DE) genes in the visual system. Unexpectedly, cuticle-related genes were the largest functional class in the pupal compound eye DE gene population, indicating differential enrichment in three distinct cuticle components: clear lens facet cuticle, highly melanized cuticle of the ocular diaphragm, which surrounds the Tribolium compound eye for internal fortification, and newly identified facet margins of the tanned cuticle, possibly enhancing external fortification. Phylogenetic, linkage, and high-throughput gene knockdown data suggest that most cuticle proteins (CPs) expressed in the Tribolium compound eye stem from the deployment of ancient CP genes. Consistent with this, TcasCPR15, which we identified as the major lens CP gene in Tribolium, is a beetle-specific but pleiotropic paralog of the ancient CPR RR-2 CP gene family. The less abundant yet most likely even more lens-specific TcasCP63 is a member of a sprawling family of noncanonical CP genes, documenting a role of local gene family expansions in the emergence of the Tribolium compound eye CP repertoire. Comparisons with Drosophila and the mosquito Anopheles gambiae reveal a steady turnover of lens-enriched CP genes during insect evolution., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)
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- 2023
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17. EyeVolve, a modular PYTHON based model for simulating developmental eye type diversification.
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Lavin R, Rathore S, Bauer B, Disalvo J, Mosley N, Shearer E, Elia Z, Cook TA, and Buschbeck EK
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Vision is among the oldest and arguably most important sensory modalities for animals to interact with their external environment. Although many different eye types exist within the animal kingdom, mounting evidence indicates that the genetic networks required for visual system formation and function are relatively well conserved between species. This raises the question as to how common developmental programs are modified in functionally different eye types. Here, we approached this issue through EyeVolve, an open-source PYTHON-based model that recapitulates eye development based on developmental principles originally identified in Drosophila melanogaster . Proof-of-principle experiments showed that this program's animated timeline successfully simulates early eye tissue expansion, neurogenesis, and pigment cell formation, sequentially transitioning from a disorganized pool of progenitor cells to a highly organized lattice of photoreceptor clusters wrapped with support cells. Further, tweaking just five parameters (precursor pool size, founder cell distance and placement from edge, photoreceptor subtype number, and cell death decisions) predicted a multitude of visual system layouts, reminiscent of the varied eye types found in larval and adult arthropods. This suggests that there are universal underlying mechanisms that can explain much of the existing arthropod eye diversity. Thus, EyeVolve sheds light on common principles of eye development and provides a new computational system for generating specific testable predictions about how development gives rise to diverse visual systems from a commonly specified neuroepithelial ground plan., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lavin, Rathore, Bauer, Disalvo, Mosley, Shearer, Elia, Cook and Buschbeck.)
- Published
- 2022
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18. Patterns of relapse following hippocampal avoidance prophylactic cranial irradiation for small cell lung carcinoma.
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Cook TA, Hoffmann MR, Ross AJ, Turnbull KJ, Westhuyzen J, and Aherne NJ
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Background: Hippocampal avoidance techniques are an evolving standard of care for patients undergoing cranial irradiation. Our aim was to assess the oncological outcomes and patterns of failure following hippocampal avoidance prophylactic cranial irradiation (HA-PCI) as a standard of care in unselected patients with both limited and extensive stage small cell lung carcinoma., Materials and Methods: Consecutive patients with small cell lung carcinoma with a complete (limited stage) or good partial (extensive stage) response following chemotherapy were eligible to receive HA-PCI, with a total dose of 25 Gray in 10 fractions. All patients had a negative baseline MRI brain scan with gadolinium prior to HA-PCI. Patients had baseline and follow up Common Toxicity Criteria Adverse Event assessments. Following completion of HA-PCI, all patients had three-monthly MRI brain scans with gadolinium until confirmation of intracranial relapse, as well as three-monthly CT of the chest, abdomen and pelvis. Overall and progression-free survival were calculated using the Kaplan-Meier method., Results: A total of 17 consecutive patients, 9 men and 8 women, with a mean age of 70 years received HA-PCI between May 2016 and June 2020 after completion of their initial chemotherapy. There were no Grade 4 or greater adverse events. No patient had an isolated hippocampal avoidance zone relapse alone; three of 17 patients had multifocal relapses that included the hippocampal avoidance zone., Conclusion: In our series, there were no hippocampal only relapses and we conclude that HA-PCI is a safe alternative to standard PCI in the setting of small cell lung cancer., Competing Interests: Conflict of interest None declared, (© 2021 Greater Poland Cancer Centre.)
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- 2021
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19. Semper's cells in the insect compound eye: Insights into ocular form and function.
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Charlton-Perkins MA, Friedrich M, and Cook TA
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- Animals, Compound Eye, Arthropod metabolism, Cornea metabolism, Cornea physiology, Drosophila genetics, Drosophila Proteins genetics, Eye metabolism, Eye Proteins genetics, Lens, Crystalline metabolism, Lens, Crystalline physiology, Neuroglia physiology, Photoreceptor Cells, Invertebrate metabolism, Retinal Cone Photoreceptor Cells metabolism, Structure-Activity Relationship, Compound Eye, Arthropod physiology, Photoreceptor Cells, Invertebrate physiology, Retinal Cone Photoreceptor Cells physiology
- Abstract
The arthropod compound eye represents one of two major eye types in the animal kingdom and has served as an essential experimental paradigm for defining fundamental mechanisms underlying sensory organ formation, function, and maintenance. One of the most distinguishing features of the compound eye is the highly regular array of lens facets that define individual eye (ommatidial) units. These lens facets are produced by a deeply conserved quartet of cuticle-secreting cells, called Semper cells (SCs). Also widely known as cone cells, SCs were originally identified for their secretion of the dioptric system, i.e. the corneal lens and underlying crystalline cones. Additionally, SCs are now known to execute a diversity of patterning and glial functions in compound eye development and maintenance. Here, we present an integrated account of our current knowledge of SC multifunctionality in the Drosophila compound eye, highlighting emerging gene regulatory modules that may drive the diverse roles for these cells. Drawing comparisons with other deeply conserved retinal glia in the vertebrate single lens eye, this discussion speaks to glial cell origins and opens new avenues for understanding sensory system support programs., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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20. Development and characterization of a chronic photoreceptor degeneration model in adult zebrafish that does not trigger a regenerative response.
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Turkalj B, Quallich D, Bessert DA, Kramer AC, Cook TA, and Thummel R
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- Animals, Animals, Genetically Modified, Apoptosis, Cell Proliferation, Chronic Disease, Disease Models, Animal, Ependymoglial Cells pathology, Retinal Degeneration physiopathology, Zebrafish, Nerve Regeneration physiology, Retinal Cone Photoreceptor Cells pathology, Retinal Degeneration diagnosis, Retinal Neurons pathology
- Abstract
Zebrafish (Danio rerio) have become a highly-utilized model system in the field of regenerative biology because of their endogenous ability to regenerate many tissues and organs, including the retina. The vast majority of previous research on retinal regeneration in adult zebrafish utilizes acute methodologies for retinal damage. Acute retinal cell death triggers a reactive gliosis response of Müller glia (MG), the resident macroglia of the retina. In addition, each activated MG undergoes asymmetric cell division to produce a neuronal progenitor, which continues to divide and ultimately gives rise to new retinal neurons. Studies using these approaches have uncovered many crucial mechanisms by which MG respond to acute damage. However, they may not adequately mimic the chronic neuronal degeneration observed in many human retinal degenerative diseases. The current study aimed to develop a new long-term, chronic photoreceptor damage and degeneration model in adult zebrafish. Comparing the subsequent cellular responses to that of the commonly-used acute high-intensity model, we found that low, continuous light exposure damaged the outer segments of both rod and cone photoreceptors, but did not result in significant apoptotic cell death, MG gliosis, or MG cell-cycle re-entry. Instead, chronic light nearly completely truncated photoreceptor outer segments and resulted in a recruitment of microglia to the area. Together, these studies present a chronic photoreceptor model that can be performed in a relatively short time frame (21 days), that may lend insight into the cellular events underlying non-regenerative photoreceptor degeneration observed in other model systems., (Copyright © 2021. Published by Elsevier Ltd.)
- Published
- 2021
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21. Redo craniotomy or bevacizumab for symptomatic steroid-refractory true or pseudoprogression following IMRT for glioblastoma.
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Cook TA, Jayamanne DT, Wheeler HR, Wong MHF, Parkinson JF, Cook RJ, Kastelan MA, Cove NJ, Brown C, and Back MF
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Background: There is minimal evidence to support decision making for symptomatic steroid-refractory pseudoprogression or true progression occurring after intensity-modulated radiation therapy (IMRT) for glioblastoma (GBM). This study audited the survival outcome of patients managed with redo craniotomy (RedoSx) or bevacizumab (BEV) for steroid-refractory mass effect after IMRT for GBM., Methods: Patients with GBM managed between 2008 and 2019 with the EORTC-NCIC Protocol were entered into a prospective database. Patients with symptomatic steroid-refractory mass effect within 6 months of IMRT managed with either RedoSx or BEV were identified for analysis. For the primary endpoint of median overall survival (OS) postintervention, outcome was analyzed in regards to potential prognostic factors, and differences between groups were assessed by log-rank analyses., Results: Of the 399 patients managed with the EORTC-NCIC Protocol, 78 required an intervention within 6 months of IMRT completion for either true or pseudoprogression (49 with RedoSx and 29 with BEV). Subsequently, 20 of the 43 patients managed with RedoSx when BEV was clinically available, required salvage with BEV within 6 months after RedoSx. Median OS postintervention was 8.7 months (95% CI: 7.84-11.61) for the total group; and 8.7 months (95% CI: 6.8-13.1) for RedoSx and 9.4 months (95% CI: 7.8-13.6) for BEV ( P = .38). Subsequent use of BEV in RedoSx patients was not associated with improved survival compared with RedoSx alone ( P = .10). Age, time from IMRT, and ECOG performance status were not associated with OS. In the RedoSx patients, immunohistochemical features such as Ki-67% reduction correlated with survival. The presence of pure necrosis and residual tumor cells only had improved survival compared with the presence of gross tumor ( P < .001)., Conclusions: At time of symptomatic steroid-refractory true or pseudoprogression following IMRT for GBM, BEV was equivalent to RedoSx in terms of OS. Pseudoprogression with residual cells at RedoSx was not associated with worse outcome compared to pure necrosis., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Neuro-Oncology and the European Association of Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2021
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22. Opposing transcriptional and post-transcriptional roles for Scalloped in binary Hippo-dependent neural fate decisions.
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Xie B, Morton DB, and Cook TA
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- Animals, Cell Differentiation genetics, Cell Line, Drosophila Proteins metabolism, Drosophila melanogaster cytology, Drosophila melanogaster genetics, Drosophila melanogaster metabolism, Gene Expression Regulation, Developmental, Intracellular Signaling Peptides and Proteins metabolism, Neurons cytology, Nuclear Proteins metabolism, Photoreceptor Cells, Invertebrate metabolism, Protein Serine-Threonine Kinases metabolism, Rhodopsin genetics, Rhodopsin metabolism, Signal Transduction genetics, Trans-Activators metabolism, Transcription Factors metabolism, YAP-Signaling Proteins, Drosophila Proteins genetics, Intracellular Signaling Peptides and Proteins genetics, Neurons metabolism, Nuclear Proteins genetics, Protein Serine-Threonine Kinases genetics, RNA Processing, Post-Transcriptional, Trans-Activators genetics, Transcription Factors genetics, Transcription, Genetic
- Abstract
The Hippo tumor suppressor pathway plays many fundamental cell biological roles during animal development. Two central players in controlling Hippo-dependent gene expression are the TEAD transcription factor Scalloped (Sd) and its transcriptional co-activator Yorkie (Yki). Hippo signaling phosphorylates Yki, thereby blocking Yki-dependent transcriptional control. In post-mitotic Drosophila photoreceptors, a bistable negative feedback loop forms between the Hippo-dependent kinase Warts/Lats and Yki to lock in green vs blue-sensitive neuronal subtype choices, respectively. Previous experiments indicate that sd and yki mutants phenocopy each other's functions, both being required for promoting the expression of the blue photoreceptor fate determinant melted (melt) and the blue-sensitive opsin Rh5. Here, we demonstrate that Sd ensures the robustness of this neuronal fate decision via multiple antagonistic gene regulatory roles. In Hippo-positive (green) photoreceptors, Sd directly represses both melt and Rh5 gene expression through defined TEAD binding sites, a mechanism that is antagonized by Yki in Hippo-negative (blue) cells. Additionally, in blue photoreceptors, Sd is required to promote the translation of the Rh5 protein through a 3'UTR-dependent and microRNA-mediated process. Together, these studies reveal that Sd can drive context-dependent cell fate decisions through opposing transcriptional and post-transcriptional mechanisms., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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23. A Complex Lens for a Complex Eye.
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Stahl AL, Baucom RS, Cook TA, and Buschbeck EK
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- Animals, Coleoptera genetics, Coleoptera growth & development, Insect Proteins genetics, Insect Proteins metabolism, Larva anatomy & histology, Larva genetics, Larva growth & development, Proteome, Transcriptome, Coleoptera anatomy & histology, Compound Eye, Arthropod anatomy & histology, Photoreceptor Cells cytology
- Abstract
A key innovation for high resolution eyes is a sophisticated lens that precisely focuses light onto photoreceptors. The eyes of holometabolous larvae range from very simple eyes that merely detect light to eyes that are capable of high spatial resolution. Particularly interesting are the bifocal lenses of Thermonectus marmoratus larvae, which differentially focus light on spectrally-distinct retinas. While functional aspects of insect lenses have been relatively well studied, little work has explored their molecular makeup, especially in regard to more complex eye types. To investigate this question, we took a transcriptomic and proteomic approach to identify the major proteins contributing to the principal bifocal lenses of T. marmoratus larvae. Mass spectrometry revealed 10 major lens proteins. Six of these share sequence homology with cuticular proteins, a large class of proteins that are also major components of corneal lenses from adult compound eyes of Drosophila melanogaster and Anopheles gambiae. Two proteins were identified as house-keeping genes and the final two lack any sequence homologies to known genes. Overall the composition seems to follow a pattern of co-opting transparent and optically dense proteins, similar to what has been described for other animal lenses. To identify cells responsible for the secretion of specific lens proteins, we performed in situ hybridization studies and found some expression differences between distal and proximal corneagenous cells. Since the distal cells likely give rise to the periphery and the proximal cells to the center of the lens, our findings highlight a possible mechanism for establishing structural differences that are in line with the bifocal nature of these lenses. A better understanding of lens composition provides insights into the evolution of proper focusing, which is an important step in the transition between low-resolution and high-resolution eyes., (© The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.)
- Published
- 2017
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24. The cuticular nature of corneal lenses in Drosophila melanogaster.
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Stahl AL, Charlton-Perkins M, Buschbeck EK, and Cook TA
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- Animals, Compound Eye, Arthropod chemistry, Cornea chemistry, Crystallins genetics, Drosophila Proteins chemistry, Drosophila Proteins genetics, Drosophila melanogaster cytology, Drosophila melanogaster growth & development, Evolution, Molecular, Eye Proteins genetics, Gene Expression Regulation, In Situ Hybridization, Lens, Crystalline chemistry, Mass Spectrometry, Pupa chemistry, Pupa cytology, Pupa growth & development, Crystallins analysis, Drosophila Proteins analysis, Drosophila melanogaster chemistry, Drosophila melanogaster genetics
- Abstract
The dioptric visual system relies on precisely focusing lenses that project light onto a neural retina. While the proteins that constitute the lenses of many vertebrates are relatively well characterized, less is known about the proteins that constitute invertebrate lenses, especially the lens facets in insect compound eyes. To address this question, we used mass spectrophotometry to define the major proteins that comprise the corneal lenses from the adult Drosophila melanogaster compound eye. This led to the identification of four cuticular proteins: two previously identified lens proteins, drosocrystallin and retinin, and two newly identified proteins, Cpr66D and Cpr72Ec. To determine which ommatidial cells contribute each of these proteins to the lens, we conducted in situ hybridization at 50% pupal development, a key age for lens secretion. Our results confirm previous reports that drosocrystallin and retinin are expressed in the two primary corneagenous cells-cone cells and primary pigment cells. Cpr72Ec and Cpr66D, on the other hand, are more highly expressed in higher order interommatidial pigment cells. These data suggest that the complementary expression of cuticular proteins give rise to the center vs periphery of the corneal lens facet, possibly facilitating a refractive gradient that is known to reduce spherical aberration. Moreover, these studies provide a framework for future studies aimed at understanding the cuticular basis of corneal lens function in holometabolous insect eyes.
- Published
- 2017
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25. Multifunctional glial support by Semper cells in the Drosophila retina.
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Charlton-Perkins MA, Sendler ED, Buschbeck EK, and Cook TA
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- Animals, Drosophila cytology, Drosophila genetics, Membrane Transport Proteins genetics, Membrane Transport Proteins metabolism, Neuroglia cytology, Photoreceptor Cells, Invertebrate cytology, Transcription Factors genetics, Transcription Factors metabolism, Transcriptome, Drosophila metabolism, Neuroglia metabolism, Photoreceptor Cells, Invertebrate metabolism
- Abstract
Glial cells play structural and functional roles central to the formation, activity and integrity of neurons throughout the nervous system. In the retina of vertebrates, the high energetic demand of photoreceptors is sustained in part by Müller glia, an intrinsic, atypical radial glia with features common to many glial subtypes. Accessory and support glial cells also exist in invertebrates, but which cells play this function in the insect retina is largely undefined. Using cell-restricted transcriptome analysis, here we show that the ommatidial cone cells (aka Semper cells) in the Drosophila compound eye are enriched for glial regulators and effectors, including signature characteristics of the vertebrate visual system. In addition, cone cell-targeted gene knockdowns demonstrate that such glia-associated factors are required to support the structural and functional integrity of neighboring photoreceptors. Specifically, we show that distinct support functions (neuronal activity, structural integrity and sustained neurotransmission) can be genetically separated in cone cells by down-regulating transcription factors associated with vertebrate gliogenesis (pros/Prox1, Pax2/5/8, and Oli/Olig1,2, respectively). Further, we find that specific factors critical for glial function in other species are also critical in cone cells to support Drosophila photoreceptor activity. These include ion-transport proteins (Na/K+-ATPase, Eaat1, and Kir4.1-related channels) and metabolic homeostatic factors (dLDH and Glut1). These data define genetically distinct glial signatures in cone/Semper cells that regulate their structural, functional and homeostatic interactions with photoreceptor neurons in the compound eye of Drosophila. In addition to providing a new high-throughput model to study neuron-glia interactions, the fly eye will further help elucidate glial conserved "support networks" between invertebrates and vertebrates.
- Published
- 2017
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26. Management of the Nasal Valve.
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Barrett DM, Casanueva FJ, and Cook TA
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- Humans, Nasal Cartilages transplantation, Nasal Obstruction diagnosis, Nasal Obstruction pathology, Nasal Obstruction physiopathology, Nose anatomy & histology, Nose physiopathology, Outcome Assessment, Health Care methods, Suture Techniques, Nasal Obstruction surgery, Nose surgery, Rhinoplasty methods
- Abstract
The nasal valve is an important consideration in patients presenting with nasal obstruction. Controversy exists regarding the anatomy, terminology, evaluation, and management of the nasal valve. Innumerable techniques with variable effects have been described in the literature. The evidence qualifying these techniques has been plentiful, though often lacking in quality. This article reviews the controversial aspects of nasal valve management applying the best available evidence to help clarify potential areas of confusion. Future research using standardized definitions, consistent methodologies, and validated outcome measures are necessary to improve the quality of evidence and impact surgical decision-making., (Copyright © 2016 Elsevier Inc. All rights reserved.)
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- 2016
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27. Radiometric Calibration of a Dual-Wavelength, Full-Waveform Terrestrial Lidar.
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Li Z, Jupp DL, Strahler AH, Schaaf CB, Howe G, Hewawasam K, Douglas ES, Chakrabarti S, Cook TA, Paynter I, Saenz EJ, and Schaefer M
- Abstract
Radiometric calibration of the Dual-Wavelength Echidna(®) Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρ(app)), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρ(app) are 8.1% for 1064 nm and 6.4% for 1548 nm. A sensitivity analysis shows that ρ(app) error is dominated by range errors at near ranges, but by lidar intensity errors at far ranges. Our semi-empirical model for radiometric calibration combines a generalized logistic function to explicitly model telescopic effects due to defocusing of return signals at near range with a negative exponential function to model the fall-off of return intensity with range. Accurate values of ρ(app) from the radiometric calibration improve the quantification of vegetation structure, facilitate the comparison and coupling of lidar datasets from different instruments, campaigns or wavelengths and advance the utilization of bi- and multi-spectral information added to 3D scans by novel spectral lidars.
- Published
- 2016
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28. Rhomboid Enhancer Activity Defines a Subset of Drosophila Neural Precursors Required for Proper Feeding, Growth and Viability.
- Author
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Gresser AL, Gutzwiller LM, Gauck MK, Hartenstein V, Cook TA, and Gebelein B
- Subjects
- Aging physiology, Animals, Diphtheria Toxin metabolism, Drosophila Proteins metabolism, Drosophila melanogaster embryology, Embryo, Nonmammalian innervation, Head, Hypopharynx metabolism, Larva growth & development, Membrane Proteins metabolism, Peptide Fragments metabolism, Satiety Response, Sense Organs metabolism, Time Factors, Drosophila Proteins genetics, Drosophila melanogaster growth & development, Drosophila melanogaster physiology, Enhancer Elements, Genetic genetics, Feeding Behavior, Membrane Proteins genetics, Neurons metabolism
- Abstract
Organismal growth regulation requires the interaction of multiple metabolic, hormonal and neuronal pathways. While the molecular basis for many of these are well characterized, less is known about the developmental origins of growth regulatory structures and the mechanisms governing control of feeding and satiety. For these reasons, new tools and approaches are needed to link the specification and maturation of discrete cell populations with their subsequent regulatory roles. In this study, we characterize a rhomboid enhancer element that selectively labels four Drosophila embryonic neural precursors. These precursors give rise to the hypopharyngeal sensory organ of the peripheral nervous system and a subset of neurons in the deutocerebral region of the embryonic central nervous system. Post embryogenesis, the rhomboid enhancer is active in a subset of cells within the larval pharyngeal epithelium. Enhancer-targeted toxin expression alters the morphology of the sense organ and results in impaired larval growth, developmental delay, defective anterior spiracle eversion and lethality. Limiting the duration of toxin expression reveals differences in the critical periods for these effects. Embryonic expression causes developmental defects and partially penetrant pre-pupal lethality. Survivors of embryonic expression, however, ultimately become viable adults. In contrast, post-embryonic toxin expression results in fully penetrant lethality. To better define the larval growth defect, we used a variety of assays to demonstrate that toxin-targeted larvae are capable of locating, ingesting and clearing food and they exhibit normal food search behaviors. Strikingly, however, following food exposure these larvae show a rapid decrease in consumption suggesting a satiety-like phenomenon that correlates with the period of impaired larval growth. Together, these data suggest a critical role for these enhancer-defined lineages in regulating feeding, growth and viability.
- Published
- 2015
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29. Hypo- or hyper-hippo: a balancing act with bHLH transcription factors.
- Author
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Cook TA
- Subjects
- Animals, Cell Cycle Checkpoints physiology, Cell Cycle Proteins metabolism, Drosophila Proteins metabolism, Drosophila melanogaster metabolism, Intracellular Signaling Peptides and Proteins metabolism, Protein Kinases metabolism, Protein Serine-Threonine Kinases metabolism, Signal Transduction
- Abstract
Balancing cell growth with differentiation is essential for tissue integrity. In this issue of Developmental Cell, Wang and Baker (2015) demonstrate unsuspected cross-talk between bHLH transcription factors, important regulators of organogenesis, with the Hippo tumor suppressor pathway to ensure that inappropriately differentiating cells are eliminated during development., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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30. Therapeutic activity of an interleukin-4/interleukin-13 dual antagonist on oxazolone-induced colitis in mice.
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Kasaian MT, Page KM, Fish S, Brennan A, Cook TA, Moreira K, Zhang M, Jesson M, Marquette K, Agostinelli R, Lee J, Williams CM, Tchistiakova L, and Thakker P
- Subjects
- Animals, Antibodies, Monoclonal administration & dosage, Antibodies, Neutralizing administration & dosage, Antibodies, Neutralizing pharmacology, Colitis, Ulcerative chemically induced, Colitis, Ulcerative drug therapy, Colitis, Ulcerative genetics, Disease Models, Animal, Gene Expression Regulation drug effects, Interleukin-13 Receptor alpha2 Subunit antagonists & inhibitors, Mice, Oxazolone adverse effects, Recombinant Fusion Proteins administration & dosage, Serum Amyloid A Protein metabolism, Serum Amyloid P-Component metabolism, Severity of Illness Index, Antibodies, Monoclonal pharmacology, Colitis, Ulcerative metabolism, Interleukin-13 antagonists & inhibitors, Interleukin-4 antagonists & inhibitors, Recombinant Fusion Proteins pharmacology
- Abstract
Interleukin-4 (IL-4) and IL-13 are critical drivers of immune activation and inflammation in ulcerative colitis, asthma and other diseases. Because these cytokines may have redundant function, dual targeting holds promise for achieving greater efficacy. We have recently described a bifunctional therapeutic targeting IL-4 and IL-13 developed on a novel protein scaffold, generated by combining specific binding domains in an optimal configuration using appropriate linker regions. In the current study, the bifunctional IL-4/IL-13 antagonist was evaluated in the murine oxazolone-induced colitis model, which produces disease with features of ulcerative colitis. The bifunctional IL-4/IL-13 antagonist reduced body weight loss throughout the 7-day course of the model, and ameliorated the increased colon weight and decreased colon length that accompany disease. Colon tissue gene expression was modulated in accordance with the treatment effect. Concentrations of serum amyloid P were elevated in proportion to disease severity, making it an effective biomarker. Serum concentrations of the bifunctional IL-4/IL-13 antagonist were inversely proportional to disease severity, colon tissue expression of pro-inflammatory genes, and serum amyloid P concentration. Taken together, these results define a panel of biomarkers signifying engagement of the IL-4/IL-13 pathway, confirm the T helper type 2 nature of disease in this model, and demonstrate the effectiveness of dual cytokine blockade., (© 2014 John Wiley & Sons Ltd.)
- Published
- 2014
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31. Evaluation of a confocal Raman probe for pathological diagnosis during colonoscopy.
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Wood JJ, Kendall C, Hutchings J, Lloyd GR, Stone N, Shepherd N, Day J, and Cook TA
- Subjects
- Adenocarcinoma pathology, Adenomatous Polyps pathology, Aged, Biopsy, Colitis, Ulcerative pathology, Colonic Polyps pathology, Discriminant Analysis, Female, Humans, In Vitro Techniques, Male, Middle Aged, Principal Component Analysis, Colon pathology, Colonic Diseases pathology, Colonoscopy instrumentation, Intestinal Mucosa pathology, Microscopy, Confocal instrumentation, Spectrum Analysis, Raman instrumentation
- Abstract
Aim: Raman spectroscopy of human tissue can provide a unique biochemical 'fingerprint' that alters with disease progression. Light incident on tissue is scattered and may be altered in wavelength, which can be represented as a Raman spectrum. A confocal fibreoptic Raman probe designed to fit down the accessory channel of a colonoscope has been constructed. This in-vitro study evaluated the accuracy of pathological diagnosis in the colon using probe-based Raman spectroscopy., Method: Biopsy samples were collected at colonoscopy, snap frozen and stored at -80 °C. Raman spectra with 10-s and 1-s acquisition periods were measured with the probe tip in contact with the mucosal surface of thawed specimens. Mathematical modelling using principal component analysis followed by linear discriminant analysis was used to correlate Raman spectra with histopathological diagnoses., Results: Three-hundred and seventy-five Raman spectra were measured from a total of 356 colon biopsies (81 of normal colon mucosa, 79 of hyperplastic polyps, 92 of adenomatous polyps, 64 of adenocarcinoma and 40 of ulcerative colitis) from 177 patients. Spectral classification accuracies comparing pathology pairs ranged from 72.1 to 95.9% for 10-s acquisitions and from 61.5 to 95.1% for 1-s acquisitions. For a three-group model of normal, adenomatous and adenocarcinoma tissue, accuracies were 74.1% for 10-s acquisitions and 63.5% for 1-s acquisitions., Conclusion: The confocal Raman probe system can distinguish between different colorectal pathologies. The probe has potential to establish Raman spectroscopy as a clinical tool for instant diagnosis at colonoscopy., (Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.)
- Published
- 2014
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32. Modeling the clinical phenotype of BTK inhibition in the mature murine immune system.
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Benson MJ, Rodriguez V, von Schack D, Keegan S, Cook TA, Edmonds J, Benoit S, Seth N, Du S, Messing D, Nickerson-Nutter CL, Dunussi-Joannopoulos K, Rankin AL, Ruzek M, Schnute ME, and Douhan J 3rd
- Subjects
- Agammaglobulinaemia Tyrosine Kinase, Animals, Cell Survival drug effects, Cell Survival genetics, Cell Survival immunology, Humans, Immunoglobulin M genetics, Immunoglobulin M immunology, Mice, Mice, Inbred CBA, Mice, Knockout, Protein Kinase Inhibitors pharmacology, Protein-Tyrosine Kinases antagonists & inhibitors, Protein-Tyrosine Kinases genetics, B-Lymphocyte Subsets immunology, Immunity, Humoral physiology, Immunologic Memory physiology, Models, Immunological, Protein-Tyrosine Kinases immunology
- Abstract
Inhibitors of Bruton's tyrosine kinase (BTK) possess much promise for the treatment of oncologic and autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. Although BTK inhibition does not impact humoral memory survival, Ag-driven clonal expansion of memory B cells and Ab-secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of chronic BTK inhibition., (Copyright © 2014 by The American Association of Immunologists, Inc.)
- Published
- 2014
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33. Perforated jejunal ulcer associated with gastric mucosa in a jejunal diverticulum.
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Bunni J, Barrett HL, and Cook TA
- Abstract
Jejunal diverticula are rare and subsequent complications even more so. The usual small bowel diverticulum encountered by general surgeons is a Meckel's. These are embryological remnants of the vitello-intestinal duct and are on the anti-mesenteric surface of the terminal ileum. They may contain heterotopic gastric or pancreatic mucosa. Herein we explore the case of a young girl who presented with features of peritonitis secondary to a complication from a jejunal diverticulum. The case, pathology, complications and treatment of jejunal diverticulosis and heterotopic gastric mucosa in the jejunum are explored.
- Published
- 2014
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34. Statistics.
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Cook TA
- Subjects
- Humans, Data Interpretation, Statistical, Decision Making, Dental Research statistics & numerical data
- Published
- 2013
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35. Selective inhibition of BTK prevents murine lupus and antibody-mediated glomerulonephritis.
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Rankin AL, Seth N, Keegan S, Andreyeva T, Cook TA, Edmonds J, Mathialagan N, Benson MJ, Syed J, Zhan Y, Benoit SE, Miyashiro JS, Wood N, Mohan S, Peeva E, Ramaiah SK, Messing D, Homer BL, Dunussi-Joannopoulos K, Nickerson-Nutter CL, Schnute ME, and Douhan J 3rd
- Subjects
- Agammaglobulinaemia Tyrosine Kinase, Animals, B-Lymphocytes drug effects, Cell Proliferation drug effects, Disease Models, Animal, Female, Germinal Center cytology, Glomerulonephritis metabolism, Glomerulonephritis prevention & control, Kidney immunology, Lupus Erythematosus, Systemic metabolism, Lupus Erythematosus, Systemic prevention & control, Lymphocyte Activation drug effects, Mice, Mice, Inbred NZB, Piperidines pharmacology, Plasma Cells drug effects, Plasma Cells immunology, Protein-Tyrosine Kinases metabolism, Pyrazoles pharmacology, Receptors, Fc, Signal Transduction drug effects, Signal Transduction immunology, T-Lymphocytes drug effects, T-Lymphocytes immunology, B-Lymphocytes immunology, Glomerulonephritis immunology, Lupus Erythematosus, Systemic immunology, Piperidines therapeutic use, Protein-Tyrosine Kinases antagonists & inhibitors, Pyrazoles therapeutic use
- Abstract
Autoantibody production and immune complex deposition within the kidney promote renal disease in patients with lupus nephritis. Thus, therapeutics that inhibit these pathways may be efficacious in the treatment of systemic lupus erythematosus. Bruton's tyrosine kinase (BTK) is a critical signaling component of both BCR and FcR signaling. We sought to assess the efficacy of inhibiting BTK in the development of lupus-like disease, and in this article describe (R)-5-amino-1-(1-cyanopiperidin-3-yl)-3-(4-[2,4-difluorophenoxy]phenyl)-1H-pyrazole-4-carboxamide (PF-06250112), a novel highly selective and potent BTK inhibitor. We demonstrate in vitro that PF-06250112 inhibits both BCR-mediated signaling and proliferation, as well as FcR-mediated activation. To assess the therapeutic impact of BTK inhibition, we treated aged NZBxW_F1 mice with PF-06250112 and demonstrate that PF-06250112 significantly limits the spontaneous accumulation of splenic germinal center B cells and plasma cells. Correspondingly, anti-dsDNA and autoantibody levels were reduced in a dose-dependent manner. Moreover, administration of PF-06250112 prevented the development of proteinuria and improved glomerular pathology scores in all treatment groups. Strikingly, this therapeutic effect could occur with only a modest reduction observed in anti-dsDNA titers, implying a critical role for BTK signaling in disease pathogenesis beyond inhibition of autoantibody production. We subsequently demonstrate that PF-06250112 prevents proteinuria in an FcR-dependent, Ab-mediated model of glomerulonephritis. Importantly, these results highlight that BTK inhibition potently limits the development of glomerulonephritis by impacting both cell- and effector molecule-mediated pathways. These data provide support for evaluating the efficacy of BTK inhibition in systemic lupus erythematosus patients.
- Published
- 2013
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36. High etendue UV camera for simultaneous four-color imaging on a single detector.
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Hicks BA, Danowski ME, Martel JF, and Cook TA
- Subjects
- Color, Colorimetry instrumentation, Colorimetry methods, Equipment Design, Image Processing, Computer-Assisted methods, Light, Optics and Photonics, Time Factors, Ultraviolet Rays, Diagnostic Imaging instrumentation
- Abstract
We describe a high etendue (0.12 cm(2) sr) camera that, without moving parts, simultaneously images four ultraviolet bands centered at 140, 175, 215, and 255 nm on a single detector into a minimum of ~7500 resolution elements. In addition to being an efficient way to make color photometric measurements of a static scene, the camera described here enables detection of spatial and temporal information that can be used to reveal energy dependent physical phenomena to complement the capability of other instruments ranging in complexity from filter wheels to integral field spectrographs.
- Published
- 2013
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37. An IL-4/IL-13 dual antagonist reduces lung inflammation, airway hyperresponsiveness, and IgE production in mice.
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Kasaian MT, Marquette K, Fish S, DeClercq C, Agostinelli R, Cook TA, Brennan A, Lee J, Fitz L, Brooks J, Vugmeyster Y, Williams CM, Lofquist A, and Tchistiakova L
- Subjects
- Animals, Anti-Inflammatory Agents, Non-Steroidal immunology, Binding Sites, Bronchial Hyperreactivity drug therapy, Bronchial Hyperreactivity immunology, CHO Cells, Cricetinae, Cross-Linking Reagents chemistry, Ear physiopathology, Female, Half-Life, Interleukin-13 Receptor alpha2 Subunit immunology, Interleukin-13 Receptor alpha2 Subunit metabolism, Mice, Mice, Inbred C57BL, Molecular Conformation, Neutralization Tests, Ovalbumin adverse effects, Ovalbumin immunology, Pneumonia immunology, Protein Binding, Protein Interaction Domains and Motifs, Single-Chain Antibodies metabolism, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Immunoglobulin E immunology, Interleukin-13 antagonists & inhibitors, Interleukin-4 antagonists & inhibitors, Pneumonia drug therapy
- Abstract
IL-4 and IL-13 comprise promising targets for therapeutic interventions in asthma and other Th2-associated diseases, but agents targeting either IL-4 or IL-13 alone have shown limited efficacy in human clinical studies. Because these cytokines may involve redundant function, dual targeting holds promise for achieving greater efficacy. We describe a bifunctional therapeutic targeting IL-4 and IL-13, developed by a combination of specific binding domains. IL-4-targeted and IL-13-targeted single chain variable fragments were joined in an optimal configuration, using appropriate linker regions on a novel protein scaffold. The bifunctional IL-4/IL-13 antagonist displayed high affinity for both cytokines. It was a potent and efficient neutralizer of both murine IL-4 and murine IL-13 bioactivity in cytokine-responsive Ba/F3 cells, and exhibited a half-life of approximately 4.7 days in mice. In a murine model of ovalbumin-induced ear swelling, the bifunctional molecule blocked both the IL-4/IL-13-dependent early-phase response and the IL-4-dependent late-phase response. In the ovalbumin-induced lung inflammation model, the bifunctional IL-4/IL-13 antagonist reduced the IL-4-dependent rise in serum IgE titers, and reduced IL-13-dependent airway hyperresponsiveness, lung inflammation, mucin gene expression, and serum chitinase responses. Taken together, these findings demonstrate the effective dual blockade of IL-4 and IL-13 with a single agent, which resulted in the modulation of a more extensive range of endpoints than could be achieved by targeting either cytokine alone.
- Published
- 2013
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38. Does use of a colonoscopy imaging device improve performance? A cohort study.
- Author
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Wood JJ, Foy CJ, Valori R, Lucarotti ME, Fowler AL, Dowler K, and Cook TA
- Subjects
- Cohort Studies, Female, Humans, Magnetic Phenomena, Male, Middle Aged, Prospective Studies, Colonoscopy standards, Diagnostic Imaging instrumentation, Intraoperative Care instrumentation
- Abstract
Background: Magnetic endoscopic imagers (MEIs) are being introduced during colonoscopy, principally for training. They aid recognition and resolution of loops. This has potential to improve technique resulting in increased completion rates and better patients' experience., Objective: To determine whether the use of a MEI improves colonoscopists' performance., Design: Cohort study., Settings: Endoscopy unit in a district general hospital., Patients: Consecutive patients undergoing colonoscopy during a 33 month period were studied., Intervention: Patients underwent colonoscopy with or without the use of a magnetic endoscopic imager., Main Outcome Measures: Patient comfort and colonoscopy completion rates with and without the use of a magnetic endoscopic imager. Other data recorded included sedation and analgesia doses, patient age and gender, bowel preparation quality, antispasmodic dose, time of day, and consciousness level., Results: A total of 5,879 colonoscopies were performed. A magnetic endoscopic imager was used for 4,873. A greater proportion of patients in the imager group had the lowest discomfort score (56.2 vs. 39.8%, logistic regression; p = 0.005). Doses of midazolam were similar in both groups (1.93 vs. 2.14 mg for imager and nonimager groups respectively). Completion rates were 94.5% with an imager and 91% without (logistic regression; p = 0.088). Logistic regression analysis showed that buscopan improved completion rate but detrimental factors included increasing patient age, discomfort, poor bowel preparation, and an afternoon procedure. Factors not influencing completion included gender, sedation and analgesia doses, and consciousness level. There was no correlation between documented reason for failure and use of the imager., Limitations: This was a nonrandomized trial although improved with logistic regression analysis., Conclusions: Magnetic endoscopic imager use improves patient comfort during colonoscopy but has not been shown to improve completion.
- Published
- 2012
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39. Complications associated with alloplastic implants in rhinoplasty.
- Author
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Winkler AA, Soler ZM, Leong PL, Murphy A, Wang TD, and Cook TA
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Child, Female, Follow-Up Studies, Humans, Incidence, Logistic Models, Male, Middle Aged, Multivariate Analysis, Outcome Assessment, Health Care, Prosthesis-Related Infections epidemiology, Retrospective Studies, Rhinoplasty methods, Young Adult, Biocompatible Materials adverse effects, Polyethylenes adverse effects, Polytetrafluoroethylene adverse effects, Prostheses and Implants adverse effects, Prosthesis Failure etiology, Prosthesis-Related Infections etiology, Rhinoplasty instrumentation
- Abstract
Objective: To evaluate the incidence of infection and extrusion of porous high-density polyethylene (pHDPE) and expanded polytetrafluoroethylene (ePTFE) implants used in rhinoplasty at a high-volume, academic facial plastic surgery practice., Methods: A total of 662 rhinoplasty procedures performed by 3 faculty surgeons from 1999 to 2008 were retrospectively reviewed. Patient demographics, medical comorbidities, operative details, and postoperative course findings were collected from patient records., Results: The incidence of postoperative infection was 2.8% (19 of 662 patients). In each case of infection, alloplastic material had been used. Infections occurred in 1 in 5 rhinoplasty procedures in which pHDPE implants were used. In patients in whom ePTFE was used alone, the infection rate was 5.3%. Exposure developed in 12% of patients in whom an alloplast was used during surgery. Factors notably not associated with infection on bivariate analysis included sex, surgeon, purpose of procedure (functional vs cosmetic), current tobacco use, or history of cocaine use (P > .05 for all)., Conclusions: To our knowledge, this study represents the largest evaluation of the use of pHDPE implants in rhinoplasty to date. Our findings are in contrast to those of previous studies regarding the use of pHDPE in rhinoplasty and parallel to those regarding the use of ePTFE. Caution is strongly recommended when considering the use of pHDPE in rhinoplasty.
- Published
- 2012
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40. Flight demonstration of a milliarcsecond pointing system for direct exoplanet imaging.
- Author
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Mendillo CB, Chakrabarti S, Cook TA, Hicks BA, and Lane BF
- Abstract
We present flight results from the optical pointing control system onboard the Planetary Imaging Concept Testbed Using a Rocket Experiment (PICTURE) sounding rocket. PICTURE (NASA mission number: 36.225 UG) was launched on 8 October 2011, from White Sands Missile Range. It attempted to directly image the exozodiacal dust disk of ϵ Eridani (K2V, 3.22 pc) down to an inner radius of 1.5 AU using a visible nulling coronagraph. The rocket attitude control system (ACS) provided 627 milliarcsecond (mas) RMS body pointing (~2'' peak-to-valley). The PICTURE fine pointing system (FPS) successfully stabilized the telescope beam to 5.1 mas (0.02λ/D) RMS using an angle tracker camera and fast steering mirror. This level of pointing stability is comparable to that of the Hubble Space Telescope. We present the hardware design of the FPS, a description of the limiting noise sources and a power spectral density analysis of the FPS and rocket ACS in-flight performance.
- Published
- 2012
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41. Integration of an abdominal Hox complex with Pax2 yields cell-specific EGF secretion from Drosophila sensory precursor cells.
- Author
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Li-Kroeger D, Cook TA, and Gebelein B
- Subjects
- Animals, Animals, Genetically Modified, Electrophoretic Mobility Shift Assay, Immunoprecipitation, Luciferases, Mutagenesis, Neural Stem Cells metabolism, PAX2 Transcription Factor metabolism, Transcription Factors metabolism, Drosophila embryology, Drosophila Proteins metabolism, Epidermal Growth Factor metabolism, Gene Expression Regulation, Developmental physiology, Homeodomain Proteins metabolism, Membrane Proteins metabolism, Multiprotein Complexes metabolism, Signal Transduction physiology
- Abstract
Cis-regulatory modules (CRMs) ensure specific developmental outcomes by mediating both proper spatiotemporal gene expression patterns and appropriate transcriptional levels. In Drosophila, the precise transcriptional control of the serine protease rhomboid regulates EGF signaling to specify distinct cell types. Recently, we identified a CRM that activates rhomboid expression and thereby EGF secretion from a subset of abdominal sensory organ precursor cells (SOPs) to induce an appropriate number of lipid-processing cells called oenocytes. Here, we use scanning mutagenesis coupled with reporter assays, biochemistry and genetics to dissect the transcriptional mechanisms regulating SOP-specific rhomboid activation. Our results show that proper spatial activity of the rhomboid CRM is dependent upon direct integration of the abdomen-specific Hox factor Abdominal-A and the SOP-restricted Pax2 factor. In addition, we show that the Extradenticle and Homothorax Hox co-factors are differentially integrated on the rhomboid CRM by abdominal versus thoracic Hox proteins in the presence of Pax2. Last, we show that Abdominal-A uses both Pax2-dependent and Pax2-independent mechanisms to stimulate rhomboid CRM activity to induce proper oenocyte numbers. Thus, these data demonstrate how a CRM integrates Hox and neural transcriptional inputs to regulate the appropriate spatial pattern and levels of EGF secretion to specify an essential cell fate.
- Published
- 2012
- Full Text
- View/download PDF
42. Design and synthesis of long acting inhaled corticosteroids for the treatment of asthma.
- Author
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Millan DS, Ballard SA, Chunn S, Dybowski JA, Fulton CK, Glossop PA, Guillabert E, Hewson CA, Jones RM, Lamb DJ, Napier CM, Payne-Cook TA, Renery ER, Selby MD, Tutt MF, and Yeadon M
- Subjects
- Administration, Inhalation, Adrenal Cortex Hormones administration & dosage, Adrenal Cortex Hormones pharmacology, Adrenergic beta-Agonists administration & dosage, Adrenergic beta-Agonists therapeutic use, Androstadienes chemistry, Androstadienes pharmacology, Animals, Anti-Asthmatic Agents administration & dosage, Anti-Asthmatic Agents pharmacology, Asthma epidemiology, Asthma physiopathology, Delayed-Action Preparations, Dose-Response Relationship, Drug, Drug Evaluation, Preclinical, Drug Therapy, Combination, Dry Powder Inhalers, Fluticasone, Hepatocytes, Humans, Liver, Lung, Microsomes, Liver, Neutrophils metabolism, Randomized Controlled Trials as Topic, Rats, Tumor Necrosis Factor-alpha biosynthesis, Tumor Necrosis Factor-alpha blood, Adrenal Cortex Hormones chemical synthesis, Adrenal Cortex Hormones pharmacokinetics, Anti-Asthmatic Agents chemical synthesis, Anti-Asthmatic Agents pharmacokinetics, Asthma drug therapy, Drug Design
- Abstract
In this Letter we present data for a novel series of ICS for the treatment of asthma. 'Inhalation by design' principles have been applied to a series of highly potent steroidal GR agonists, with a focus on optimising the potential therapeutic index in human. Pharmacokinetic properties were tuned with high intrinsic clearance and low oral bioavailability in mind, to minimise systemic exposure and reduce systemically driven adverse events. High CYP mediated clearance as well as glucuronidation were targeted to achieve high intrinsic clearance coupled with multiple routes of clearance to minimise drug-drug interactions. Furthermore, pharmaceutical properties such as stability, crystallinity and solubility were considered to ensure compatibility with a dry powder inhaler. This work culminated in the identification of the clinical candidate 15, which demonstrates preclinically the desired efficacy and safety profiles confirming its potential as an inhaled agent for the treatment of asthma., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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43. The lens in focus: a comparison of lens development in Drosophila and vertebrates.
- Author
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Charlton-Perkins M, Brown NL, and Cook TA
- Subjects
- Animals, Cell Adhesion Molecules genetics, Cell Adhesion Molecules metabolism, Cell Differentiation, Crystallins genetics, Crystallins metabolism, Drosophila genetics, Drosophila metabolism, Gene Expression Regulation, Developmental, Genes, Insect, Lens, Crystalline cytology, Lens, Crystalline metabolism, Models, Biological, Multipotent Stem Cells cytology, Multipotent Stem Cells metabolism, Signal Transduction, Species Specificity, Vertebrates genetics, Vertebrates metabolism, Drosophila growth & development, Lens, Crystalline growth & development, Vertebrates growth & development
- Abstract
The evolution of the eye has been a major subject of study dating back centuries. The advent of molecular genetics offered the surprising finding that morphologically distinct eyes rely on conserved regulatory gene networks for their formation. While many of these advances often stemmed from studies of the compound eye of the fruit fly, Drosophila melanogaster, and later translated to discoveries in vertebrate systems, studies on vertebrate lens development far outnumber those in Drosophila. This may be largely historical, since Spemann and Mangold's paradigm of tissue induction was discovered in the amphibian lens. Recent studies on lens development in Drosophila have begun to define molecular commonalities with the vertebrate lens. Here, we provide an overview of Drosophila lens development, discussing intrinsic and extrinsic factors controlling lens cell specification and differentiation. We then summarize key morphological and molecular events in vertebrate lens development, emphasizing regulatory factors and networks strongly associated with both systems. Finally, we provide a comparative analysis that highlights areas of research that would help further clarify the degree of conservation between the formation of dioptric systems in invertebrates and vertebrates.
- Published
- 2011
- Full Text
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44. IL-13 antibodies influence IL-13 clearance in humans by modulating scavenger activity of IL-13Rα2.
- Author
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Kasaian MT, Raible D, Marquette K, Cook TA, Zhou S, Tan XY, and Tchistiakova L
- Subjects
- Animals, Antibody-Dependent Cell Cytotoxicity immunology, Dose-Response Relationship, Immunologic, Drug Delivery Systems, Extracellular Space immunology, Extracellular Space metabolism, HT29 Cells, Humans, Interleukin-13 antagonists & inhibitors, Interleukin-13 Receptor alpha2 Subunit antagonists & inhibitors, Interleukin-13 Receptor alpha2 Subunit biosynthesis, Macaca fascicularis, Mice, Mice, Inbred BALB C, Receptors, Scavenger antagonists & inhibitors, Receptors, Scavenger physiology, Interleukin-13 immunology, Interleukin-13 metabolism, Interleukin-13 Receptor alpha2 Subunit metabolism, Isoantibodies physiology, Receptors, Scavenger metabolism
- Abstract
Human studies using Abs to two different, nonoverlapping epitopes of IL-13 suggested that epitope specificity can have a clinically significant impact on clearance of IL-13. We propose that Ab modulation of IL-13 interaction with IL-13Rα2 underlies this effect. Two Abs were administered to healthy subjects and mild asthmatics in separate dose-ranging studies and allergen-challenge studies. IMA-638 allows IL-13 interaction with IL-13Rα1 or IL-13Rα2 but blocks recruitment of IL-4Rα to the IL-13/IL-13Rα1 complex, whereas IMA-026 competes with IL-13 interaction with IL-13Rα1 and IL-13Rα2. We found ∼10-fold higher circulating titer of captured IL-13 in subjects treated with IMA-026 compared with those administered IMA-638. To understand how this difference could be related to epitope, we asked whether either Ab affects IL-13 internalization through cell surface IL-13Rα2. Humans inducibly express cell surface IL-13Rα2 but lack the soluble form that regulates IL-13 responses in mice. Cells with high IL-13Rα2 expression rapidly and efficiently depleted extracellular IL-13, and this activity persisted in the presence of IMA-638 but not IMA-026. The potency and efficiency of this clearance pathway suggest that cell surface IL-13Rα2 acts as a scavenger for IL-13. These findings could have important implications for the design and characterization of IL-13 antagonists.
- Published
- 2011
- Full Text
- View/download PDF
45. The alcohol relapse situation appraisal questionnaire: development and validation.
- Author
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Martin RA, Mackinnon SM, Johnson JE, Myers MG, Cook TA, and Rohsenow DJ
- Subjects
- Adult, Aged, Aged, 80 and over, Alcoholism prevention & control, Alcohols metabolism, Ethanol metabolism, Female, Humans, Male, Middle Aged, Psychometrics methods, Reproducibility of Results, Risk, Risk Assessment methods, Young Adult, Alcoholism psychology, Secondary Prevention, Surveys and Questionnaires, Temperance psychology
- Abstract
Background: The role of cognitive appraisal of the threat of alcohol relapse has received little attention. A previous instrument, the Relapse Situation Appraisal Questionnaire (RSAQ), was developed to assess cocaine users' primary appraisal of the threat of situations posing a high risk for cocaine relapse. The purpose of the present study was to modify the RSAQ in order to measure primary appraisal in situations involving a high risk for alcohol relapse., Methods: The development and psychometric properties of this instrument, the Alcohol Relapse Situation Appraisal Questionnaire (A-RSAQ), were examined with two samples of abstinent adults with alcohol abuse or dependence. Factor structure and validity were examined in Study 1 (N=104). Confirmation of the factor structure and predictive validity was assessed in Study 2 (N=159)., Results: Results demonstrated construct, discriminant and predictive validity and reliability of the A-RSAQ., Discussion: Results support the important role of primary appraisal of degree of risk in alcohol relapse situations., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
46. Proneural and abdominal Hox inputs synergize to promote sensory organ formation in the Drosophila abdomen.
- Author
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Gutzwiller LM, Witt LM, Gresser AL, Burns KA, Cook TA, and Gebelein B
- Subjects
- Abdomen embryology, Animals, Basic Helix-Loop-Helix Transcription Factors genetics, Basic Helix-Loop-Helix Transcription Factors metabolism, Cell Differentiation, Cell Lineage, Drosophila Proteins metabolism, Embryo, Nonmammalian metabolism, Gene Expression Regulation, Developmental, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Nuclear Proteins metabolism, Sense Organs cytology, Transcription Factors metabolism, Drosophila embryology, Drosophila Proteins genetics, Neurons metabolism, Nuclear Proteins genetics, Sense Organs embryology, Transcription Factors genetics
- Abstract
The atonal (ato) proneural gene specifies a stereotypic number of sensory organ precursors (SOP) within each body segment of the Drosophila ectoderm. Surprisingly, the broad expression of Ato within the ectoderm results in only a modest increase in SOP formation, suggesting many cells are incompetent to become SOPs. Here, we show that the SOP promoting activity of Ato can be greatly enhanced by three factors: the Senseless (Sens) zinc finger protein, the Abdominal-A (Abd-A) Hox factor, and the epidermal growth factor (EGF) pathway. First, we show that expression of either Ato alone or with Sens induces twice as many SOPs in the abdomen as in the thorax, and do so at the expense of an abdomen-specific cell fate: the larval oenocytes. Second, we demonstrate that Ato stimulates abdominal SOP formation by synergizing with Abd-A to promote EGF ligand (Spitz) secretion and secondary SOP recruitment. However, we also found that Ato and Sens selectively enhance abdominal SOP development in a Spitz-independent manner, suggesting additional genetic interactions between this proneural pathway and Abd-A. Altogether, these experiments reveal that genetic interactions between EGF-signaling, Abd-A, and Sens enhance the SOP-promoting activity of Ato to stimulate region-specific neurogenesis in the Drosophila abdomen., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
47. Molecular evidence for color discrimination in the Atlantic sand fiddler crab, Uca pugilator.
- Author
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Rajkumar P, Rollmann SM, Cook TA, and Layne JE
- Subjects
- Amino Acid Sequence, Animal Communication, Animals, Brachyura anatomy & histology, Brachyura physiology, Color, In Situ Hybridization, Fluorescence, Molecular Sequence Data, Opsins chemistry, Opsins metabolism, Photoreceptor Cells, Invertebrate metabolism, Phylogeny, Sequence Alignment, Brachyura genetics, Color Vision genetics, Opsins genetics
- Abstract
Fiddler crabs are intertidal brachyuran crabs that belong to the genus Uca. Approximately 97 different species have been identified, and several of these live sympatrically. Many have species-specific body color patterns that may act as signals for intra- and interspecific communication. To understand the behavioral and ecological role of this coloration we must know whether fiddler crabs have the physiological capacity to perceive color cues. Using a molecular approach, we identified the opsin-encoding genes and determined their expression patterns across the eye of the sand fiddler crab, Uca pugilator. We identified three different opsin-encoding genes (UpRh1, UpRh2 and UpRh3). UpRh1 and UpRh2 are highly related and have similarities in their amino acid sequences to other arthropod long- and medium-wavelength-sensitive opsins, whereas UpRh3 is similar to other arthropod UV-sensitive opsins. All three opsins are expressed in each ommatidium, in an opsin-specific pattern. UpRh3 is present only in the R8 photoreceptor cell, whereas UpRh1 and UpRh2 are present in the R1-7 cells, with UpRh1 expression restricted to five cells and UpRh2 expression present in three cells. Thus, one photoreceptor in every ommatidium expresses both UpRh1 and UpRh2, providing another example of sensory receptor coexpression. These results show that U. pugilator has the basic molecular machinery for color perception, perhaps even trichromatic vision.
- Published
- 2010
- Full Text
- View/download PDF
48. Separable transcriptional regulatory domains within Otd control photoreceptor terminal differentiation events.
- Author
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McDonald EC, Xie B, Workman M, Charlton-Perkins M, Terrell DA, Reischl J, Wimmer EA, Gebelein BA, and Cook TA
- Subjects
- Amino Acid Sequence, Animals, Conserved Sequence genetics, Drosophila Proteins chemistry, Gene Expression Regulation, Developmental, Homeodomain Proteins chemistry, Molecular Sequence Data, Morphogenesis genetics, Photoreceptor Cells, Invertebrate metabolism, Promoter Regions, Genetic genetics, Rhodopsin genetics, Rhodopsin metabolism, Sequence Alignment, Sequence Deletion genetics, Sequence Homology, Amino Acid, Cell Differentiation genetics, Drosophila Proteins genetics, Drosophila melanogaster cytology, Drosophila melanogaster genetics, Homeodomain Proteins genetics, Photoreceptor Cells, Invertebrate cytology, Regulatory Sequences, Nucleic Acid genetics, Transcription, Genetic
- Abstract
Orthodenticle (Otd)-related transcription factors are essential for anterior patterning and brain morphogenesis from Cnidaria to Mammals, and genetically underlie several human retinal pathologies. Despite their key developmental functions, relatively little is known regarding the molecular basis of how these factors regulate downstream effectors in a cell- or tissue-specific manner. Many invertebrate and vertebrate species encode two to three Otd proteins, whereas Drosophila encodes a single Otd protein. In the fly retina, Otd controls rhabdomere morphogenesis of all photoreceptors and regulates distinct Rhodopsin-encoding genes in a photoreceptor subtype-specific manner. Here, we performed a structure-function analysis of Otd during Drosophila eye development using in vivo rescue experiments and in vitro transcriptional regulatory assays. Our findings indicate that Otd requires at least three distinct transcriptional regulatory domains to control photoreceptor-specific rhodopsin gene expression and photoreceptor morphogenesis. Our results also uncover a previously unknown role for Otd in preventing co-expression of sensory receptors in blue vs. green-sensitive R8 photoreceptors. Sequence analysis indicates that many of the transcriptional regulatory domains identified here are conserved in multiple Diptera Otd-related proteins. Thus, these studies provide a basis for identifying shared molecular pathways involved in a wide range of developmental processes., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
49. Pph13 and orthodenticle define a dual regulatory pathway for photoreceptor cell morphogenesis and function.
- Author
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Mishra M, Oke A, Lebel C, McDonald EC, Plummer Z, Cook TA, and Zelhof AC
- Subjects
- Animals, Animals, Genetically Modified, Base Sequence, Binding Sites genetics, DNA genetics, DNA metabolism, Drosophila Proteins genetics, Drosophila melanogaster cytology, Drosophila melanogaster genetics, Gene Expression Profiling, Gene Expression Regulation, Developmental, Genes, Insect, Homeodomain Proteins genetics, Microscopy, Electron, Transmission, Mutation, Photoreceptor Cells, Invertebrate ultrastructure, Promoter Regions, Genetic, Rhodopsin genetics, Rhodopsin physiology, Drosophila Proteins physiology, Drosophila melanogaster growth & development, Drosophila melanogaster physiology, Homeodomain Proteins physiology, Photoreceptor Cells, Invertebrate cytology, Photoreceptor Cells, Invertebrate physiology
- Abstract
The function and integrity of photoreceptor cells are dependent upon the creation and maintenance of specialized apical structures: membrane discs/outer segments in vertebrates and rhabdomeres in insects. We performed a molecular and morphological comparison of Drosophila Pph13 and orthodenticle (otd) mutants to investigate the transcriptional network controlling the late stages of rhabdomeric photoreceptor cell development and function. Although Otd and Pph13 have been implicated in rhabdomere morphogenesis, we demonstrate that it is necessary to remove both factors to completely eliminate rhabdomere formation. Rhabdomere absence is not the result of degeneration or a failure of initiation, but rather the inability of the apical membrane to transform and elaborate into a rhabdomere. Transcriptional profiling revealed that Pph13 plays an integral role in promoting rhabdomeric photoreceptor cell function. Pph13 regulates Rh2 and Rh6, and other phototransduction genes, demonstrating that Pph13 and Otd control a distinct subset of Rhodopsin-encoding genes in adult visual systems. Bioinformatic, DNA binding and transcriptional reporter assays showed that Pph13 can bind and activate transcription via a perfect Pax6 homeodomain palindromic binding site and the Rhodopsin core sequence I (RCSI) found upstream of Drosophila Rhodopsin genes. In vivo studies indicate that Pph13 is necessary and sufficient to mediate the expression of a multimerized RCSI reporter, a marker of photoreceptor cell specificity previously suggested to be regulated by Pax6. Our studies define a key transcriptional regulatory pathway that is necessary for late Drosophila photoreceptor development and will serve as a basis for better understanding rhabdomeric photoreceptor cell development and function.
- Published
- 2010
- Full Text
- View/download PDF
50. Atonal, Senseless, and Abdominal-A regulate rhomboid enhancer activity in abdominal sensory organ precursors.
- Author
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Witt LM, Gutzwiller LM, Gresser AL, Li-Kroeger D, Cook TA, and Gebelein B
- Subjects
- Animals, Drosophila cytology, Drosophila metabolism, Embryo, Nonmammalian, Protein Binding genetics, Sense Organs metabolism, Transcription Factors genetics, Drosophila genetics, Transcription Factors metabolism
- Abstract
The atonal (ato) proneural gene specifies different numbers of sensory organ precursor (SOP) cells within distinct regions of the Drosophila embryo in an epidermal growth factor-dependent manner through the activation of the rhomboid (rho) protease. How ato activates rho, and why it does so in only a limited number of sensory cells remains unclear. We previously identified a rho enhancer (RhoBAD) that is active within a subset of abdominal SOP cells to induce larval oenocytes and showed that RhoBAD is regulated by an Abdominal-A (Abd-A) Hox complex and the Senseless (Sens) transcription factor. Here, we show that ato is also required for proper RhoBAD activity and oenocyte formation. Transgenic reporter assays reveal RhoBAD contains two conserved regions that drive SOP gene expression: RhoD mediates low levels of expression in both thoracic and abdominal SOP cells, whereas RhoA drives strong expression within abdominal SOP cells. Ato indirectly stimulates both elements and enhances RhoA reporter activity by interfering with the ability of the Sens repressor to bind DNA. As RhoA is also directly regulated by Abd-A, we propose a model for how the Ato and Sens proneural factors are integrated with an abdominal Hox factor to regulate region-specific SOP gene expression., (Copyright 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
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