22 results on '"Harvey TM"'
Search Results
2. "I hope to feel part of something bigger than my immediate world…"; the values and attitudes that motivate participation in a virtual international midwifery student experience.
- Author
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Harvey TM and Wallace HJ
- Abstract
Problem: As ethnic and cultural diversity of societies increases, healthcare professionals are required to provide culturally appropriate care for the communities they serve., Background: One way to prepare midwifery students for the diverse settings and women they will care for, is to provide short-term international study experience opportunities, to nurture the development of cultural sensitivity and humility. During the COVID-19 pandemic, the higher education industry was challenged to identify innovative ways to develop student's cultural competences, without international travel. A midwifery virtual study program was an innovative way to provide an international experience for students while borders were closed. Research on impacts of virtual short-term international study experiences and midwifery students' motivation to participate is sparce., Aim: The aim of this study was to gain an understanding of what motivates midwifery students to participate in a virtual short-term international study experience., Methods: A descriptive qualitative design using reflective thematic analysis to analyse students' written journal entries and reflections., Findings: An overarching theme of 'Develop compassion' was identified, underpinned by three sub themes, 'Deepening understanding and knowledge', 'Expanding cultural identify and attitudes', and 'strengthening professional self'., Discussion and Conclusion: Students' motivation to participate in a virtual short-term international study experience included aspects of improving and enhancing their developing professional self, including compassion, in anticipation of supporting their career progression and the effectiveness of the care they deliver. The findings are relevant for academics and administrators involved in study abroad programs for ongoing improvement of quality cultural learning opportunities for health discipline students., Competing Interests: Conflict of Interest The authors whose names are listed immediately below certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2025 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2025
- Full Text
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3. 'Listen with an open-heart always' - A qualitative study exploring transformational learning opportunities for Australian midwifery students participating in a virtual international study experience.
- Author
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Wallace HJ and Harvey TM
- Subjects
- Humans, Australia, Female, COVID-19, Education, Distance, Learning, International Educational Exchange, Adult, Qualitative Research, Students, Nursing psychology, Midwifery education, Education, Nursing, Baccalaureate
- Abstract
Aim: To explore whether virtual short term international study experiences (VSTISE) facilitate transformational learning., Background: Transformational learning is recognised as beneficial and desirable for health students to experience. Such learning may contribute to students developing deeper understanding of themselves and of those to whom they provide care. Transformational learning has been demonstrated to increase students' confidence with and empathy for, caring for people from diverse backgrounds, increasing students' knowledge and awareness of social justice and health equity issues. Previously, undergraduate midwifery students at an Australian University have had the opportunity to potentially experience transformational learning through participation in short-term international experiences. Covid-19 resulted in the transitioning from face-to-face international experiences to virtual, online programs., Design: A qualitative research design was informed by transformational learning theory, with a reflexive thematic analysis process. Bachelor of Midwifery students from an Australian University who were participating in the virtual programs were invited to take part. Critical reflective journal entries were guided by prompt questions aligned with a reflective model., Method: Reflective thematic analysis of students' written reflections guided by a transformational learning framework., Results: Ten students consented and shared their critical reflective journal entries. Transformational learning is possible via virtual international study programs, with midwifery students demonstrating such learning in domains such as developing cultural sensitivity, developing insight into privilege and power and increasing recognition of the importance of a global midwifery identity., Conclusions: Virtual programs may increase equitable access to international opportunities while deepening cultural sensitivity, compassion and professional growth of midwifery students., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
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4. Comparative proteomic analysis of different stages of breast cancer tissues using ultra high performance liquid chromatography tandem mass spectrometer.
- Author
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Al-Wajeeh AS, Salhimi SM, Al-Mansoub MA, Khalid IA, Harvey TM, Latiff A, and Ismail MN
- Subjects
- Adult, Aged, Chromatography, High Pressure Liquid, Female, Humans, Malaysia, Middle Aged, Neoplasm Invasiveness, Neoplasm Staging, Proteome metabolism, Proteomics, Tandem Mass Spectrometry, Biomarkers, Tumor metabolism, Breast Neoplasms metabolism, Breast Neoplasms pathology, Carcinogenesis metabolism, Carcinoma, Ductal metabolism, Carcinoma, Ductal pathology, Neoplasm Proteins metabolism
- Abstract
Background: Breast cancer is the fifth most prevalent cause of death among women worldwide. It is also one of the most common types of cancer among Malaysian women. This study aimed to characterize and differentiate the proteomics profiles of different stages of breast cancer and its matched adjacent normal tissues in Malaysian breast cancer patients. Also, this study aimed to construct a pertinent protein pathway involved in each stage of cancer., Methods: In total, 80 samples of tumor and matched adjacent normal tissues were collected from breast cancer patients at Seberang Jaya Hospital (SJH) and Kepala Batas Hospital (KBH), both in Penang, Malaysia. The protein expression profiles of breast cancer and normal tissues were mapped by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The Gel-Eluted Liquid Fractionation Entrapment Electrophoresis (GELFREE) Technology System was used for the separation and fractionation of extracted proteins, which also were analyzed to maximize protein detection. The protein fractions were then analyzed by tandem mass spectrometry (LC-MS/MS) analysis using LC/MS LTQ-Orbitrap Fusion and Elite. This study identified the proteins contained within the tissue samples using de novo sequencing and database matching via PEAKS software. We performed two different pathway analyses, DAVID and STRING, in the sets of proteins from stage 2 and stage 3 breast cancer samples. The lists of molecules were generated by the REACTOME-FI plugin, part of the CYTOSCAPE tool, and linker nodes were added in order to generate a connected network. Then, pathway enrichment was obtained, and a graphical model was created to depict the participation of the input proteins as well as the linker nodes., Results: This study identified 12 proteins that were detected in stage 2 tumor tissues, and 17 proteins that were detected in stage 3 tumor tissues, related to their normal counterparts. It also identified some proteins that were present in stage 2 but not stage 3 and vice versa. Based on these results, this study clarified unique proteins pathways involved in carcinogenesis within stage 2 and stage 3 breast cancers., Conclusions: This study provided some useful insights about the proteins associated with breast cancer carcinogenesis and could establish an important foundation for future cancer-related discoveries using differential proteomics profiling. Beyond protein identification, this study considered the interaction, function, network, signaling pathway, and protein pathway involved in each profile. These results suggest that knowledge of protein expression, especially in stage 2 and stage 3 breast cancer, can provide important clues that may enable the discovery of novel biomarkers in carcinogenesis., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
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5. Changes in blood-brain barrier permeability and ultrastructure, and protein expression in a rat model of cerebral hypoperfusion.
- Author
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Sekaran H, Gan CY, A Latiff A, Harvey TM, Mohd Nazri L, Hanapi NA, Azizi J, and Yusof SR
- Subjects
- Animals, Astrocytes metabolism, Brain metabolism, Brain Edema metabolism, Brain Ischemia metabolism, Cerebrovascular Disorders metabolism, Cerebrovascular Disorders physiopathology, Chromatography, Liquid, Electrophoresis, Gel, Two-Dimensional, Endothelial Cells metabolism, Male, Permeability, Rats, Rats, Sprague-Dawley, Reperfusion Injury metabolism, Tandem Mass Spectrometry, Blood-Brain Barrier metabolism, Blood-Brain Barrier ultrastructure, Cerebrovascular Circulation physiology
- Abstract
Cerebral hypoperfusion involved a reduction in cerebral blood flow, leading to neuronal dysfunction, microglial activation and white matter degeneration. The effects on the blood-brain barrier (BBB) however, have not been well-documented. Here, two-vessel occlusion model was adopted to mimic the condition of cerebral hypoperfusion in Sprague-Dawley rats. The BBB permeability to high and low molecular weight exogenous tracers i.e. Evans blue dye and sodium fluorescein respectively, showed marked extravasation of the Evans blue dye in the frontal cortex, posterior cortex and thalamus-midbrain at day 1 following induction of cerebral hypoperfusion. Transmission electron microscopy revealed brain endothelial cell and astrocyte damages including increased pinocytotic vesicles and formation of membrane invaginations in the endothelial cells, and swelling of the astrocytes' end-feet. Investigation on brain microvessel protein expressions using two-dimensional (2D) gel electrophoresis coupled with LC-MS/MS showed that proteins involved in mitochondrial energy metabolism, transcription regulation, cytoskeleton maintenance and signaling pathways were differently expressed. The expression of aconitate hydratase, heterogeneous nuclear ribonucleoprotein, enoyl Co-A hydratase and beta-synuclein were downregulated, while the opposite observed for calreticulin and enhancer of rudimentary homolog. These findings provide insights into the BBB molecular responses to cerebral hypoperfusion, which may assist development of future therapeutic strategies., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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6. Triglyceride profiling in adipose tissues from obese insulin sensitive, insulin resistant and type 2 diabetes mellitus individuals.
- Author
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Al-Sulaiti H, Diboun I, Banu S, Al-Emadi M, Amani P, Harvey TM, Dömling AS, Latiff A, and Elrayess MA
- Subjects
- Adult, Discriminant Analysis, Fatty Acids metabolism, Female, Humans, Least-Squares Analysis, Male, Molecular Weight, Omentum metabolism, Subcutaneous Fat metabolism, Adipose Tissue metabolism, Diabetes Mellitus, Type 2 metabolism, Insulin Resistance, Obesity metabolism, Triglycerides metabolism
- Abstract
Background: Lipid intermediates produced during triacylglycerols (TAGs) synthesis and lipolysis in adipocytes interfere with the intracellular insulin signaling pathway and development of insulin resistance. This study aims to compare TAG species and their fatty acid composition in adipose tissues from insulin sensitive (IS), insulin resistant (IR) and type 2 diabetes mellitus (T2DM) obese individuals., Methods: Human subcutaneous and omental adipose tissue biopsies were obtained from 64 clinically characterized obese individuals during weight reduction surgery. TAGs were extracted from the adipose tissues using the Bligh and Dyer method, then were subjected to non-aqueous reverse phase ultra-high performance liquid chromatography and full scan mass spectrometry acquisition and data dependent MS/MS on LTQ dual cell linear ion trap. TAGs and their fatty acid contents were identified and compared between IS, IR and T2DM individuals and their levels were correlated with metabolic traits of participants and the adipogenic potential of preadipocyte cultures established from their adipose tissues., Results: Data revealed 76 unique TAG species in adipose tissues identified based on their exact mass. Analysis of TAG levels revealed a number of TAGs that were significantly altered with disease progression including C46:4, C48:5, C48:4, C38:1, C50:3, C40:2, C56:3, C56:4, C56:7 and C58:7. Enrichment analysis revealed C12:0 fatty acid to be associated with TAGs least abundant in T2DM whereas C18:3 was found in both depleted and enriched TAGs in T2DM. Significant correlations of various adipose tissue-derived TAG species and metabolic traits were observed, including age and body mass index, systemic total cholesterol, TAGs, and interleukin-6 in addition to adipogenic potential of preadipocytes derived from the same adipose tissues., Conclusion: Pilot data suggest that adipose tissues from obese IR and T2DM individuals exhibit TAG-specific signatures that may contribute to their increased risk compared to their IS counterparts. Future experiments are warranted to investigate the functional relevance of these specific lipidomic profiles.
- Published
- 2018
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7. Perceptions of Taiwanese nursing students' English-language progression following interactive scenario development and role play.
- Author
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Robinson CI, Harvey TM, and Tseng 曾翊瑄 M
- Subjects
- Adult, Australia, Female, Humans, Male, Surveys and Questionnaires, Taiwan, Young Adult, Communication, Education, Nursing, Baccalaureate methods, Language, Learning, Students, Nursing psychology
- Abstract
Background: The English language has been recognised as an international language, enabling the globalisation of education and work opportunities. An institute in Taiwan has committed to strengthening English teaching by implementing a student-centred teaching and learning activity using role play. In addition, the involvement of a visiting teacher from Australia has been established., Method: Data collection consisted of a questionnaire that collected qualitative and quantitative data that revealed student perceptions and attitudes towards learning English including nursing terminology, teamwork and communication., Results: Fifty five of sixty students participating in the activity completed the questionnaire. Students regarded this as a positive experience for learning English, collegiality and teamwork., Conclusion: This project revealed that students who are not generally exposed to English-speaking people enjoyed this experience. They gained confidence in their ability to learn English in a collegial atmosphere where teamwork and supportive relationships were developed, despite the perception that learning English was difficult.
- Published
- 2016
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8. The Association Between Serum Biomarkers of Collagen Turnover and Subsequent Anterior Cruciate Ligament Rupture.
- Author
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Svoboda SJ, Owens BD, Harvey TM, Tarwater PM, Brechue WF, and Cameron KL
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- Adolescent, Adult, Anterior Cruciate Ligament Injuries etiology, Case-Control Studies, Enzyme-Linked Immunosorbent Assay, Female, Humans, Logistic Models, Male, Middle Aged, Risk, Rupture etiology, Young Adult, Anterior Cruciate Ligament Injuries epidemiology, Biomarkers blood, Collagen metabolism, Rupture epidemiology
- Abstract
Background: No study has attempted to associate the levels of preinjury serum biomarkers of collagen turnover with the subsequent risk of anterior cruciate ligament (ACL) injury., Hypothesis: Preinjury serum biomarkers of collagen turnover would be associated with the subsequent risk of ACL injury., Study Design: Case-control study; Level of evidence, 3., Methods: We conducted a case-control study with 45 ACL-injured cases and 45 controls matched for sex, age, height, and weight. In addition to the matching criteria, controls had no history of major joint injury. Baseline preinjury serum samples were obtained from the Department of Defense Serum Repository for all subjects. Samples were assessed for 2 serum biomarkers of collagen synthesis (CPII and CS846) and 2 markers of collagen degradation (C1,2C and C2C) through commercially available enzyme-linked immunosorbent assay (ELISA) kits. All ELISAs were performed in triplicate. Conditional logistic regression models were used to analyze the data., Results: Univariate results suggested that both biomarkers for collagen degradation (C1,2C and C2C) were significantly associated with the subsequent likelihood of ACL injury. Serum C2C and C1,2C concentration at baseline were associated with odds ratios (ORs) of 2.05 (95% CI, 1.30-3.23; P = .001) and 3.02 (95% CI, 1.60-5.71; P = .002), respectively. Baseline serum CPII concentrations were also associated with subsequent ACL injury. Serum CPII concentration at baseline was associated with an OR of 4.41 (95% CI, 1.87-10.38; P = .001). Baseline serum CS846 levels approached significance (OR = 0.77; 95% CI, 0.57-1.03; P = .080). Multivariable models suggested that preinjury CPII and C2C concentrations at baseline are important indicators of subsequent ACL injury risk., Conclusion: Preinjury differences in serum biomarker levels of collagen turnover suggest that collagen metabolism in individuals who go on to tear an ACL may be different when compared with a matched control group with no history of major joint injury. These differences may be reflective of different preinjury biochemical and/or biomechanical risk profiles or genetic factors that subsequently affect both collagen metabolism and ACL injury risk., (© 2016 The Author(s).)
- Published
- 2016
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9. Changes in serum biomarkers of cartilage turnover after anterior cruciate ligament injury.
- Author
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Svoboda SJ, Harvey TM, Owens BD, Brechue WF, Tarwater PM, and Cameron KL
- Subjects
- Adolescent, Anterior Cruciate Ligament metabolism, Case-Control Studies, Female, Humans, Male, Randomized Controlled Trials as Topic, Young Adult, Anterior Cruciate Ligament Injuries, Biomarkers blood, Cartilage metabolism, Knee Injuries blood
- Abstract
Background: Biomarkers of cartilage turnover and joint metabolism have a potential use in detecting early degenerative changes after a traumatic knee joint injury; however, no study has analyzed biomarkers before an anterior cruciate ligament (ACL) injury and again after injury or in comparison with a similar group of uninjured controls., Hypothesis: Changes in serum biomarker levels and the ratio of cartilage degradation to synthesis, from baseline to follow-up, would be significantly different between ACL-injured patients and uninjured controls., Study Design: Case-control study; Level of evidence, 3., Methods: This case-control study was conducted to examine changes in serum biomarkers of cartilage turnover following ACL injury in a young athletic population. Specifically, 2 markers for type II collagen and aggrecan synthesis (CPII and CS846, respectively) and 2 markers of types I and II degradation and type II degradation only (C1,2C and C2C, respectively) were studied. Preinjury baseline serum samples and postinjury follow-up samples were obtained for 45 ACL-injured cases and 45 uninjured controls matched for sex, age, height, and weight., Results: Results revealed significant decreases in C1,2C (P = .042) and C2C (P = .006) over time in the ACL-injured group when compared with the controls. The change in serum concentrations of CS846 from baseline to follow-up was also significantly different between the ACL-injured patients and uninjured controls (P = .002), as was the change between groups in the ratio of C2C:CPII over time (P = .013). No preinjury differences in the ratio of C1,2C:CPII or C2C:CPII were observed between groups; however, postinjury differences were observed for both ratios., Conclusion: Changes in biomarker concentrations after an ACL injury suggest an alteration in cartilage turnover and joint metabolism in those sustaining ACL injuries compared with uninjured matched controls.
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- 2013
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10. Comparison of Rosenbaum pupillometry card using red and blue light to Colvard and Iowa pupillometers.
- Author
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Ho LY, Harvey TM, Scherer J, Balasubramaniam M, Dhaliwal DK, and Mah FS
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- Adult, Cross-Sectional Studies, Eye Color, Female, Humans, Male, Middle Aged, Reproducibility of Results, Young Adult, Diagnostic Techniques, Ophthalmological instrumentation, Iris anatomy & histology, Pupil physiology
- Abstract
Purpose: To compare four scotopic pupil measuring techniques to determine whether a statistically significant difference exists among the techniques for each observer or between the observers for each technique., Methods: Cross-sectional study performed on 200 eyes of 100 healthy individuals. Two observers performed pupillometry four times per pupil using the Rosenbaum card with red light, Rosenbaum card with blue light, Iowa pupillometer, and Colvard pupillometer. All measurements were recorded in scotopic conditions with each examiner masked to the other's results., Results: Both examiners measured mean pupil diameters > 6.0 mm for all modalities except the Colvard device whose mean measurements were the smallest. The Iowa pupillometer and Rosenbaum card with red light produced the largest pupil measurements and were the most similar for both observers. The mean pupil diameter obtained by observer 1 was smaller compared with observer 2 while using the Rosenbaum card with blue light, but this was not significant (P = .2574). The mean pupil diameter obtained by observer 1 was larger compared with observer 2 while using the Colvard pupillometer and this was statistically different after adjusting for eye color (P = .0370). The mean pupil diameters of blue irides and brown irides are significantly higher than the measurements obtained for hazel irides (P = .0271 and P = .0445, respectively)., Conclusions: Due to the complex interaction among observer, pupillometry technique, and iris color, one cannot compare the four techniques to each other with the same observer, nor can one compare the two observers irrespective of the technique.
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- 2010
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11. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations.
- Author
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Kerksick CM, Wilborn CD, Campbell WI, Harvey TM, Marcello BM, Roberts MD, Parker AG, Byars AG, Greenwood LD, Almada AL, Kreider RB, and Greenwood M
- Subjects
- Absorptiometry, Photon, Adaptation, Physiological drug effects, Adaptation, Physiological physiology, Adolescent, Adult, Anabolic Agents administration & dosage, Anabolic Agents pharmacology, Analysis of Variance, Body Composition drug effects, Body Composition physiology, Creatine metabolism, Creatine pharmacokinetics, Creatine pharmacology, Double-Blind Method, Drug Therapy, Combination, Exercise Test, Humans, Inositol administration & dosage, Inositol metabolism, Inositol pharmacology, Muscle Strength drug effects, Muscle Strength physiology, Safety, Creatine administration & dosage, Dietary Supplements, Inositol analogs & derivatives, Resistance Training methods, Weight Lifting physiology
- Abstract
Coingestion of D-pinitol with creatine (CR) has been reported to enhance creatine uptake. The purpose of this study was to evaluate whether adding D-pinitol to CR affects training adaptations, body composition, whole-body creatine retention, and/or blood safety markers when compared to CR ingestion alone after 4 weeks of resistance training. Twenty-four resistance trained males were randomly assigned in a double-blind manner to creatine + pinitol (CRP) or creatine monohydrate (CR) prior to beginning a supervised 4-week resistance training program. Subjects ingested a typical loading phase (i.e., 20 g/d-1 for 5 days) before ingesting 5 g/d-1 the remaining 23 days. Performance measures were assessed at baseline (T0), week 1 (T1), and week 4 (T2) and included 1 repetition maximum (1RM) bench press (BP), 1RM leg press (LP), isokinetic knee extension, and a 30-second Wingate anaerobic capacity test. Fasting blood and body composition using dual-energy x-ray absorptiometry (DEXA) were determined at T1 and T3. Data were analyzed by repeated measures analysis of variance (ANOVA). Creatine retention increased (p < 0.001) in both groups as a result of supplementation but was not different between groups (p > 0.05). Significant improvements in upper- and lower-body strength and body composition occurred in both groups. However, significantly greater increases in lean mass and fat-free mass occurred in the CR group when compared to CRP (p <0.05). Adding D-pinitol to creatine monohydrate does not appear to facilitate further physiological adaptations while resistance training. Creatine monohydrate supplementation helps to improve strength and body composition while resistance training. Data from this study assist in determining the potential role the addition of D-pinitol to creatine may aid in facilitating training adaptations to exercise.
- Published
- 2009
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12. Novel delivery method to reduce endothelial injury in descemet stripping automated endothelial keratoplasty.
- Author
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Kuo AN, Harvey TM, and Afshari NA
- Subjects
- Anthraquinones, Cell Count, Cell Survival, Cell Transplantation methods, Corneal Transplantation instrumentation, Female, Humans, Middle Aged, Tissue Donors, Trypan Blue, Corneal Diseases surgery, Corneal Transplantation methods, Descemet Membrane surgery, Endothelium, Corneal pathology, Endothelium, Corneal transplantation, Intraoperative Complications prevention & control
- Abstract
Purpose: To present a novel technique to deliver the endothelial graft in small incision Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) and to compare graft trauma between forceps delivery and the novel technique., Design: Laboratory investigation with an interventional case report., Methods: Ten pairs of human donor corneas were sectioned using an automated microkeratome system (Moria ALTK System, Antony, France). The recipient model was prepared by creating a 3 mm clear corneal wound in another human donor cornea. For each pair of corneas, one endothelial graft underwent single-fold delivery with forceps, while the other was delivered with the novel cartridge based technique. Each graft was stained with 0.25% trypan blue and 0.2% alizarin red, and digital photomicrographs were taken. A proportion of graft injury was calculated and differences were analyzed. Subsequently, a patient requiring DSAEK underwent the modified novel insertion technique., Results: After insertion, the mean proportion of graft endothelial injury from forceps delivery through the ex vivo model was 26.02% (n = 10, standard deviation [SD] +/- 14.85%). The mean proportion of graft endothelial injury from cartridge delivery was 9.85% (n = 10, SD +/- 4.33%). The median difference between the two methods was -13%, representing less endothelial injury with the cartridge. This difference was statistically significant (P = .006). The patient who underwent DSAEK with this technique had improved visual acuity and a clear graft at five months., Conclusions: In our surgical model, inserting an endothelial graft through a small corneal wound using a novel cartridge-based technique created significantly less endothelial damage than with forceps insertion. Clinically, this technique was performed without complication.
- Published
- 2008
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13. Small incision insertion of posterior lamellar button.
- Author
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Harvey TM
- Subjects
- Humans, Treatment Outcome, Corneal Transplantation methods, Endothelium, Corneal transplantation, Minimally Invasive Surgical Procedures
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- 2006
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14. Triple-quadrupole mass spectrometry studies of nitroaromatic emissions from different diesel engines.
- Author
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Henderson TR, Sun JD, Royer RE, Harvey TM, Hunt DH, Fulford JE, Lovette AM, Davidson WR, Clark CR, and Li AP
- Published
- 1983
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15. Hydrocarbon gases emitted from vehicles on the road. 2. Determination of emission rates from diesel and spark-ignition vehicles.
- Author
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Hampton CV, Pierson WR, Harvey TM, and Schuetzle D
- Published
- 1983
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16. Analytical methods for the determination of cannabinoids in biological media.
- Author
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Wall ME, Harvey TM, Bursey JT, Brine DR, and Rosenthal D
- Subjects
- Chromatography, Gas, Chromatography, Thin Layer, Dronabinol analysis, Humans, Male, Mass Spectrometry, Methods, Cannabis analysis
- Abstract
A pharmacokinetic study of the blood plasma levels in man of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol and cannabinol has been carried out by means of combined gas chromatographic-mass spectral analysis. In some cases comparison of the data was obtained on the same sample using thin layer chromatography of radiolabeled samples and electron capture gas-liquid chromatography. For the mass spectral studies appropriately deuterium labeled analogs of the previously named compounds were used both as internal standards and as a carrier for the relatively small amounts of nonlabeled drug present in plasma. Blood samples were obtainted at periodic intervals up to 24 hours from volunteers receiving 4-5 mg delta9-THC intravenously. After extraction and "clean-up" by Sephadex chromatography, the extracts were concentrated and subjected to glc-ms in the electron impact (ei) mode or alternatively with a chemical ionization (ci) source, in which case preliminary chromatography could be omitted. In all cases calibration curves were obtained from replicate analyses of spiked plasma containing the internal standard and various quantities of the cannabinoid under analysis. A typical biphasic elimination of the drug was observed with rapid elimination of delta9-THC from the blood over a period of 40 min followed by a much slower elimination up to 24 hours. The experimental data show that 11-hydroxy-delta9-THC is found in the plasma in quantities only about one-twentieth to one-twenty-fifth the values found for delta9-THC. Cannabinol was not found in significant quantities. Good agreement was obtained between the mass spectral analyses and the thin layer chromatography or electron capture gas-liquid chromatographic procedures.
- Published
- 1976
17. Differential leakage of intracellular substances from imbibing soybean seeds.
- Author
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Duke SH, Kakefuda G, and Harvey TM
- Abstract
Leakage of electrolytes, substances absorbing UV light, and enzymic activities from imbibing soybean (Glycine max [L.] Merr.) seeds were compared to determine the extent that passive diffusion and cellular rupture contribute to each. Imbibing seeds with testae removed had average Arrhenius energies of activation (5 to 25 degrees C) of 3.0 and 15.8 kilocalories per mole, respectively, for the leakage of electrolytes and embryo malate dehydrogenase activity. Leakage of embryo enzymes from imbibing seeds was dependent on loss of testa integrity and subsequent loss of cellular membrane integrity or inability to seal preexisting membrane discontinuities. These data suggest that electrolyte leakage from imbibing seeds is primarily by passive diffusion, whereas the diffusion of intracellular macromolecules is primarily dependent on physiological phenomena affecting membrane integrity. Kinetic data and examination of the composition of seed leachates indicated that the leakage of substances absorbing UV light during imbibition is due to both passive diffusion of low molecular weight solutes and macromolecules released from ruptured cells.
- Published
- 1983
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18. Hydrocarbon gases emitted from vehicles on the road. 1. A qualitative gas chromatography/mass spectrometry survey.
- Author
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Hampton CV, Pierson WR, Harvey TM, Updegrove WS, and Marano RS
- Published
- 1982
- Full Text
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19. Comparison of gas chromatography mass spectrometry methods for the determination of delta9-tetrahydrocannabinol in plasma.
- Author
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Rosenthal D, Harvey TM, Bursey JT, Brine DR, and Wall ME
- Subjects
- Chromatography, Gas methods, Chromatography, Thin Layer, Humans, Dronabinol blood, Mass Spectrometry methods
- Abstract
A method for the identification of delta9-tetrahydrocannabinol by gas chromatography mass spectrometry has been developed, and this method has been compared with other techniques, such as detection via thin-layer chromatography using tritium labeled delta9-tetrahydrocannibinol and a dual gas chromatographic method. The gas chromatographic mass spectrometric method was found to be equal or superior to other techniques and has the added advantage of being highly specific for the compound analyzed. An alternate approach using chemical ionization is also described; however, this procedure does not show significant advantages over the electron impact method. These methods show a practical lower detection limit of 500 pg ml-1 of plasma in clinical practice.
- Published
- 1978
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20. MS/MS analysis of diesel emissions and fuels treated with NO2.
- Author
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Henderson TR, Royer RE, Clark CR, Harvey TM, and Hunt DF
- Subjects
- Gas Chromatography-Mass Spectrometry, Mass Spectrometry, Mutagens analysis, Polycyclic Compounds analysis, Fuel Oils analysis, Nitrogen Dioxide toxicity, Petroleum analysis, Vehicle Emissions analysis
- Abstract
Correlations between direct-acting mutagens in diesel emissions and the activity of nitroaromatic compounds have been noted, but detection and identification of nitro-compounds in diesel particulates has remained an elusive problem. In the results reported here, MS/MS (tandem mass spectrometry) was found to detect nitroaromatic compounds in fractionated and unfractionated diesel soot extracts. The nitro-compounds detected ranged from two- to four-ring polynuclear aromatic hydrocarbon derivatives and were primarily mono-nitro derivatives. An aromatic fraction from diesel fuel reacted with NO2 resembled diesel exhaust extracts from an engine operating on the same fuel. Therefore, it is possible that nitroaromatic derivatives in diesel exhaust may be in part due to unburned fuel residues reacting with NO chi formed in the combustion process. The utility of MS/MS in comparing complex mixtures from different sources or subfractions thereof is discussed.
- Published
- 1982
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21. Detection of nitroaromatic compounds on coal combustion particles.
- Author
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Hanson RL, Henderson TR, Hobbs CH, Clark CR, Carpenter RL, Dutcher JS, Harvey TM, and Hunt DF
- Subjects
- Coal analysis, Mutagens analysis, Nitro Compounds analysis, Polycyclic Compounds analysis
- Abstract
Mutagenic and nonmutagenic extracts of fly ash from fluidized bed combustion were analyzed to determine the compounds responsible for the direct mutagenic activity (mutagenic activity that does not require added metabolic enzymes in the Salmonella mutagenicity assay). Some nitro derivatives of polycyclic aromatic hydrocarbons which are direct acting mutagens were detected by tandem triple quadrupole mass spectrometry. Treatment of a mutagenic and a nonmutagenic extract with excess N2O4 resulted in 28- and 3200-fold increases, respectively, in direct mutagenicity in Salmonella typhimurium strain TA98 and an increase in the relative abundance of nitroaromatic compounds. Polycyclic aromatic compounds were also detected and tentatively identified by gas chromatography-mass spectrometry. Since, previous studies have shown that polycyclic aromatic hydrocarbons may react with NO2 to form direct-acting mutagens, it appears that the direct-acting mutagens in these fly ash extracts may be products of reactions of polycyclic aromatic hydrocarbons with NOX in the combustion gases.
- Published
- 1983
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22. GC/MS and MS/MS studies of diesel exhaust mutagenicity and emissions from chemically-defined fuels.
- Author
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Henderson TR, Sun JD, Li AP, Hanson RL, Bechtold WE, Harvey TM, Shabanowitz J, and Hunt DF
- Published
- 1984
- Full Text
- View/download PDF
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