49 results on '"Shen DT"'
Search Results
2. A Platform for the Synthesis of Diverse Phosphonyl and Thiofunctionalized Sulfoxonium Ylides.
- Author
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Zou WX, Hu Q, Shen DT, Wu WR, Wei J, Yang ZF, Bao MZ, Liu X, and Zhang SS
- Abstract
A practical strategy for the construction of diverse phosphonyl and thiofunctionalized sulfoxonium ylides via controllable monofunctionalization of hybrid I
(III) /S(VI) ylides is presented. This process allows efficient P-H insertion of I(III) /S(VI) ylides under Cu catalysis, enabling the synthesis of phosphonyl sulfoxonium ylides, whereas reaction with sulfur-containing reagents including AgSCF3 , KSC(S)OR, and KSCN under mild conditions resulted in α-trifluoromethylthiolation, dithiocarbanation, and thiocyanation of sulfoxonium ylides accordingly. Of note, wide substrate compatibility (108 examples), excellent efficiency (up to 99% yield), gram-scale experiments, and various product derivatizations highlight the synthetic utility of this protocol.- Published
- 2024
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3. Berberine Enhances Intestinal Mucosal Barrier Function by Promoting Vitamin D Receptor Activity.
- Author
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Huang YQ, Liu JL, Chen GX, Shen DT, Zhu W, Chen XL, Liu FB, and Hou QK
- Subjects
- Rats, Animals, Receptors, Calcitriol genetics, Receptors, Calcitriol metabolism, Intestinal Barrier Function, Occludin genetics, Occludin metabolism, Maternal Deprivation, Diarrhea, Intestinal Mucosa, Irritable Bowel Syndrome, Berberine pharmacology, Berberine therapeutic use
- Abstract
Objective: To evaluate if berberine can act on vitamin D receptors (VDR) and thereby regulate the expression of tight junction proteins (TJPs) in irritable bowel syndrame-diarrhea-predominant (IBS-D) rats., Methods: The newborn rats were induced into IBS-D rat model via neonatal maternal separation combined with acetic acid chemical stimulation. After modeling, the model was evaluated and rats were divided into the control group and berberine treatment groups (0.85, 1.7 and 3.4 mg/kg, once a day for 2 weeks). The distal colon was obtained and colonic epithelial cells (CECs) were isolated and cultured after IBS-D model evaluation. The vitamin D receptor response element (VDRE) reporter gene was determined in the CECs of IBS-D rats to analyze the effect of berberine on the VDRE promoter. VDR overexpression or silencing technology was used to analyze whether VDR plays a role in promoting intestinal barrier repair, and to determine which region of VDR plays a role in berberine-regulated intestinal TJPs., Results: The IBS-D rat model was successfully constructed and the symptoms were improved by berberine in a dose-dependent manner (P<0.05). The activity of VDRE promoter was also effectively promoted by berberine (P<0.05). Berberine increased the expression of TJPs in IBS-D CECs (P<0.05). VDR expression was significantly increased after transfection of different domains of VDR when compared to normal control and basic plasmid groups (all P<0.05). RT-qPCR and Western blot results showed that compared with the blank group, expressions of occludin and zonula occludens-1 were significantly higher in VDR containing groups (all P<0.05). Berberine plus pCMV-Myc-VDR-N group exerted the highest expression levels of occludin and zonula occludens-1 (P<0.05)., Conclusion: Berberine enhances intestinal mucosal barrier function of IBS-D rats by promoting VDR activity, and the main site of action is the N-terminal region of VDR., (© 2023. The Chinese Journal of Integrated Traditional and Western Medicine Press and Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2024
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4. Rh(III)-Catalyzed Dienylation and Cyclopropylation of 1,2,3-Benzotriazinones with Alkylidenecyclopropanes.
- Author
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Liu YZ, Zeng YF, Wei J, Xiao L, Shu B, Song JL, Zou WX, Shen DT, Chen SY, Zheng YC, and Zhang SS
- Abstract
Rh (III)-catalyzed dienylation and cyclopropylation of 1,2,3-benzotriazinones with alkylidenecyclopropanes (ACPs) has been achieved. Different from the previous reports of 1,2,3-benzotriazinones, the triazinone ring remained intact in this C-H bond functionlization reaction. Also, the denitrogenative cyclopropylation could also be realized by changing the reaction temperature. This protocol is featured with high E selectivity, wide substrate scope, and divergent structures of products.
- Published
- 2023
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5. Divergent Synthesis of Tetrasubstituted Phenols via [3 + 3] Cycloaddition Reaction of Vinyl Sulfoxonnium Ylides with Cyclopropenones.
- Author
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Chen SY, Zeng YF, Zou WX, Shen DT, Zheng YC, Song JL, and Zhang SS
- Subjects
- Catalysis, Cycloaddition Reaction, Copper, Metals
- Abstract
Two categories of tetrasubstituted phenols were prepared via the cycloaddition reaction of vinyl sulfoxonnium ylides with cyclopropenones in a switchable manner. Copper carbenoid was proposed as the active intermediate in the process of 2,3,4,5-tetrasubstituted phenols formation, while 2,3,5,6-tetrasubstituted phenols were generated via the direct [3 + 3] annulation of vinyl sulfoxonnium ylides with cyclopropenones under metal-free conditions. Further synthetic applications were also demonstrated.
- Published
- 2023
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6. Global prevalence of occult hepatitis B: A systematic review and meta-analysis.
- Author
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Ji DZ, Pang XY, Shen DT, Liu SN, Goyal H, and Xu HG
- Subjects
- DNA, Viral, Hepatitis B Surface Antigens genetics, Hepatitis B virus, Humans, Prevalence, HIV Infections complications, HIV Infections epidemiology, Hepatitis B, Hepatitis B, Chronic epidemiology
- Abstract
The study aimed to investigate the prevalence and risk factors associated with occult hepatitis B virus (HBV) infection (OBI) in the global population. We searched PubMed, Embase, CINAHL, Cochrane and Web of Science from database inception through 27 Dec, 2018. Studies reporting HBV-DNA serological data in previously undiagnosed hepatitis B patients were included. The data were further categorized according to the presence of risk factors. After an initial screening of 2,325 records, we finally included 98 articles about the prevalence of OBI from 34 countries and regions. The OBI prevalence was 0.82% (95% CI:0.69-0.96) in the general population, 16.26% (95% CI:10.97-22.34) in HIV patients, 13.99% (95% CI:8.33-20.79) in patients with other liver diseases, 4.25% (95% CI:1.64-7.87) in haemodialysis patients and 5.14% (95% CI:2.26-9.01) patients with other risk factors. In conclusion, OBI prevalence varies significantly across different populations and nations, which deserve attention from the public health authorities. Our results generate further epidemiological data to identify the population with OBI, which has important clinical implications in finding these high-risk populations to design preventive and management strategies., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2022
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7. Risky family climates presage increased cellular aging in young adulthood.
- Author
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Brody GH, Yu T, Chen E, Kobor M, Beach SRH, Lei MK, Barr A, Lin DT, and Miller GE
- Subjects
- Adult, Child, Chronic Disease, Humans, Prospective Studies, Risk Factors, Young Adult, Aging, Cellular Senescence
- Abstract
A scientific consensus is emerging that children reared in risky family climates are prone to chronic diseases and premature death later in life. Few prospective data, however, are available to inform the mechanisms of these relationships. In a prospective study involving 323 Black families, we sought to determine whether, and how, childhood risky family climates are linked to a potential risk factor for later-life disease: increases in cellular aging (indexed by epigenetic aging). As hypothesized, risky family climates were associated with greater outflows of the stress hormones epinephrine and norepinephrine at ages 19 and 20 years; this, in turn, led to increases in cellular aging across ages 20-27 years. If sustained, these tendencies may place children from risky family climates on a trajectory toward the chronic diseases of aging., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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8. Epidemiology estimates of hepatitis D in individuals co-infected with human immunodeficiency virus and hepatitis B virus, 2002-2018: A systematic review and meta-analysis.
- Author
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Shen DT, Han PC, Ji DZ, Chen HY, Cao WD, Goyal H, and Xu HG
- Subjects
- HIV, Hepatitis B virus, Hepatitis Delta Virus, Humans, Prevalence, Seroepidemiologic Studies, Coinfection epidemiology, HIV Infections complications, HIV Infections epidemiology, Hepatitis B complications, Hepatitis B epidemiology, Hepatitis D complications, Hepatitis D epidemiology
- Abstract
Hepatitis delta virus (HDV) is an obligate satellite of hepatitis B virus (HBV). HIV/HDV co-infection is associated with a high rate of hepatic decompensation events and death. We aimed to characterize the epidemiology of HDV infection in HIV/HBV co-infected individuals. We systematically searched PubMed, Embase, Cochrane Library, Web of Science, CINAHL and Scopus for studies published from 1 Jan 2002 to 7 May 2018 measuring prevalence of HDV among the HIV population. Pooled seroprevalence was calculated with the DerSimonian-Laird random-effects model. Our search returned 4624 records, 38 of which met the inclusion and exclusion criteria. These studies included data for 63 cohorts from 18 countries and regions. The overall HDV seroprevalence of HIV-infected individuals was 1.03% (95% CI 0.43-1.85) in 2002-2018 globally. Moreover, the estimated pooled HDV seroprevalence among the general population was 1.07% (95% CI 0.65-1.59) in 2002-2018, which was not significantly different from the HDV seroprevalence of individuals living with HIV (p = 0.951). The overall HDV seroprevalence of the HBsAg positive population was 12.15% (95% CI 10.22-14.20), p = 0.434 when compared with the corresponding data of HIV/HBV co-infected individuals. This meta-analysis suggested that there was no difference between the HDV seroprevalence in HIV-infected individuals and the general population., (© 2021 John Wiley & Sons Ltd.)
- Published
- 2021
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9. Differences in delta virus hepatitis diagnosis methods and its effect on the hepatitis D prevalence.
- Author
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Shen DT, Goyal H, and Xu HG
- Subjects
- Hepatitis B Surface Antigens, Humans, Prevalence, Hepatitis D diagnosis, Hepatitis D epidemiology, Hepatitis Delta Virus genetics
- Abstract
Competing Interests: Competing interests: None declared.
- Published
- 2020
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10. Hepatitis D: not a rare disease anymore: global update for 2017-2018.
- Author
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Shen DT, Ji DZ, Chen HY, Goyal H, Pan S, and Xu HG
- Subjects
- Hepatitis Delta Virus, Humans, Prevalence, Rare Diseases, Hepatitis B, Hepatitis D
- Abstract
Competing Interests: Competing interests: None declared.
- Published
- 2020
- Full Text
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11. Development and validation of the prognostic value of ferritin in adult patients with Hemophagocytic Lymphohistiocytosis.
- Author
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Zhou J, Zhou J, Shen DT, Goyal H, Wu ZQ, and Xu HG
- Subjects
- Adult, Biomarkers, Ferritins, Humans, Prognosis, Retrospective Studies, Lymphohistiocytosis, Hemophagocytic
- Abstract
Background: Hemophagocytic Lymphohistiocytosis (HLH) is a rare clinical syndrome with high mortality rate. The diagnosis of HLH draws on a constellation of clinical and laboratory abnormalities including extremely high serum ferritin levels. However, no biomarker has been firmly established as a clinically useful prognostic tool in HLH patients. We aimed to perform a retrospective analysis of two independent cohorts to explore the prognostic value of discharge serum ferritin for newly diagnosed adult HLH patients who recently started treatment. The prognostic value of serum ferritin levels at discharge (will be called as post-treatment ferritin level) was initially evaluated in a "test cohort" of 161 previously untreated consecutive adult HLH patients. It was then validated in a second cohort of 68 consecutive previously untreated patients (validation cohort)., Results: Multivariate analysis revealed that significantly high post-treatment serum ferritin levels (>1050 μg/L) were associated with a higher risk of death and poor overall survival in the test cohort (hazard ratio (HR): 3.176, 95% confidence interval (CI) 1.468-6.869, P = 0.003), and the validation cohort (HR: 13.412, 95%CI 1.716-104.816, P = 0.013). At 6-month follow-up period in the test cohort, patients with a > 81% decrease in the serum ferritin level had a significantly higher probability of survival when compared with the patients with ≥14% increase in the serum ferritin level (94% vs. 31%, P < 0.001). Similar findings were observed on the analysis of the decrease in the serum ferritin level in the validation cohort., Conclusions: These results suggest that the serum ferritin level can be used as an independent prognostic marker in the adult HLH patients.
- Published
- 2020
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12. Prevalence and burden of hepatitis D virus infection in the global population: a systematic review and meta-analysis.
- Author
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Chen HY, Shen DT, Ji DZ, Han PC, Zhang WM, Ma JF, Chen WS, Goyal H, Pan S, and Xu HG
- Subjects
- Coinfection epidemiology, Hepatitis B Surface Antigens blood, Hepatitis B, Chronic epidemiology, Hepatitis D transmission, Humans, Prevalence, Risk Factors, Risk-Taking, Sexual Behavior, Substance Abuse, Intravenous complications, Substance Abuse, Intravenous epidemiology, Global Health statistics & numerical data, Hepatitis D epidemiology
- Abstract
Objective: Hepatitis D virus (HDV) is a defective virus that completes its life cycle only with hepatitis B virus (HBV). The HBV with HDV super-infection has been considered as one of the most severe forms of the chronic viral hepatitis. However, there is a scarcity of data on the global burden of HDV infection., Design: We searched PubMed, Embase, Cochrane Library and China Knowledge Resource Integrated databases from 1 January 1977 to 31 December 2016. We included studies with a minimum sample size of 50 patients. Our study analysed data from a total of 40 million individuals to estimate the prevalence of HDV by using Der-Simonian Laird random-effects model. The data were further categorised according to risk factors., Results: From a total of 2717 initially identified studies, only 182 articles from 61 countries and regions met the final inclusion criteria. The overall prevalence of HDV was 0.98% (95% CI 0.61 to 1.42). In HBsAg-positive population, HDV pooled prevalence was 14.57% (95% CI 12.93 to 16.27): Seroprevalence was 10.58% (95% CI 9.14 to 12.11) in mixed population without risk factors of intravenous drug use (IVDU) and high-risk sexual behaviour (HRSB). It was 37.57% (95% CI 29.30 to 46.20) in the IVDU population and 17.01% (95% CI 10.69 to 24.34) in HRSB population., Conclusion: We found that approximately 10.58% HBsAg carriers (without IVDU and HRSB) were coinfected with HDV, which is twofold of what has been estimated before. We also noted a substantially higher HDV prevalence in the IVDU and HRSB population. Our study highlights the need for increased focus on the routine HDV screening and rigorous implementation of HBV vaccine programme., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
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13. ABHD17 proteins are novel protein depalmitoylases that regulate N-Ras palmitate turnover and subcellular localization.
- Author
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Lin DT and Conibear E
- Subjects
- Animals, Cell Line, Disks Large Homolog 4 Protein, Humans, Intracellular Membranes metabolism, Intracellular Signaling Peptides and Proteins metabolism, Protein Transport, GTP Phosphohydrolases metabolism, Gene Expression Regulation, Membrane Proteins metabolism, Palmitates metabolism, Protein Processing, Post-Translational
- Abstract
Dynamic changes in protein S-palmitoylation are critical for regulating protein localization and signaling. Only two enzymes - the acyl-protein thioesterases APT1 and APT2 - are known to catalyze palmitate removal from cytosolic cysteine residues. It is unclear if these enzymes act constitutively on all palmitoylated proteins, or if additional depalmitoylases exist. Using a dual pulse-chase strategy comparing palmitate and protein half-lives, we found knockdown or inhibition of APT1 and APT2 blocked depalmitoylation of Huntingtin, but did not affect palmitate turnover on postsynaptic density protein 95 (PSD95) or N-Ras. We used activity profiling to identify novel serine hydrolase targets of the APT1/2 inhibitor Palmostatin B, and discovered that a family of uncharacterized ABHD17 proteins can accelerate palmitate turnover on PSD95 and N-Ras. ABHD17 catalytic activity is required for N-Ras depalmitoylation and re-localization to internal cellular membranes. Our findings indicate that the family of depalmitoylation enzymes may be substantially broader than previously believed.
- Published
- 2015
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14. [Impact of attack frequency and therapy strategies on outcome of patients with vasovagal syncope].
- Author
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Shen DT, Lin ZQ, Xie ZQ, Zhan YY, Luo Y, Zhong YX, and Li ZL
- Subjects
- Adolescent, Adult, Female, Humans, Male, Middle Aged, Physical Therapy Modalities, Prognosis, Treatment Outcome, Young Adult, Syncope, Vasovagal diagnosis, Syncope, Vasovagal therapy
- Abstract
Objective: To analyze the impact of attack frequency as well as therapy strategies on outcome of patients with vasovagal syncope (VVS)., Methods: A total of 159 patients (aged from 15 - 59 years old) with VVS were included in this study. Patients were divided into low frequency (< 3) group (n = 95) and high (≥ 3) frequency group (n = 64) according to the attack frequency in the past 5 years at the primary survey. Patients received one of the three therapies: no treatment, physical therapy, and comprehensive treatment. All cases were followed up with telephone or outpatient visit for 24 months., Results: Incidence of syncope was significantly higher in the high frequency group and in the low frequency group [40.6% (26/64) vs. 11.6% (11/95), P < 0.01]. The overall improvement rate was significantly higher in the low frequency group than that of high frequency group (P < 0.01). Improvement rate was significantly higher in the physical therapy subgroup and the comprehensive treatment subgroup than no treatment subgroup for patients with low attack frequency [81.8% (27/33) vs. 47.1% (8/17), P < 0.05; 82.2% (37/45) vs. 47.1% (8/17), P < 0.05], and in comprehensive treatment subgroup than in physical therapy subgroups observed between and [62.2% (28/45) vs. 31.6% (6/19), P < 0.05] for patients with high attack frequency., Conclusion: Outcome is related to previous attack frequency for patients with VVS, physical therapy is effective for reducing the recurrence rate of syncope in VVS patients with low attack frequency while physical therapy combined with pharmacotherapy should be applied for VVS patients with high attack frequency to improve outcome.
- Published
- 2012
15. Protein kinase Cdelta regulates antigen receptor-induced lytic granule polarization in mouse CD8+ CTL.
- Author
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Ma JS, Monu N, Shen DT, Mecklenbräuker I, Radoja N, Haydar TF, Leitges M, Frey AB, Vukmanovic S, and Radoja S
- Subjects
- Animals, CD8 Antigens analysis, Cytoplasmic Granules immunology, Exocytosis genetics, Granzymes metabolism, Mice, Mice, Mutant Strains, Protein Kinase C-delta antagonists & inhibitors, Protein Kinase C-delta genetics, Receptors, Antigen, T-Cell agonists, Sequence Deletion, T-Lymphocytes, Cytotoxic enzymology, T-Lymphocytes, Cytotoxic ultrastructure, Cytoplasmic Granules ultrastructure, Exocytosis immunology, Protein Kinase C-delta physiology, Receptors, Antigen, T-Cell immunology, T-Lymphocytes, Cytotoxic immunology
- Abstract
Lytic granule exocytosis is the major pathway used by CD8+ CTL to kill virally infected and tumor cells. Despite the obvious importance of this pathway in adaptive T cell immunity, the molecular identity of enzymes involved in the regulation of this process is poorly characterized. One signal known to be critical for the regulation of granule exocytosis-mediated cytotoxicity in CD8+ T cells is Ag receptor-induced activation of protein kinase C (PKC). However, it is not known which step of the process is regulated by PKC. In addition, it has not been determined to date which of the PKC family members is required for the regulation of lytic granule exocytosis. By combination of pharmacological inhibitors and use of mice with targeted gene deletions, we show that PKCdelta is required for granule exocytosis-mediated lytic function in mouse CD8+ T cells. Our studies demonstrate that PKCdelta is required for lytic granule exocytosis, but is dispensable for activation, cytokine production, and expression of cytolytic molecules in response to TCR stimulation. Importantly, defective lytic function in PKCdelta-deficient cytotoxic lymphocytes is reversed by ectopic expression of PKCdelta. Finally, we show that PKCdelta is not involved in target cell-induced reorientation of the microtubule-organizing center, but is required for the subsequent exocytosis step, i.e., lytic granule polarization. Thus, our studies identify PKCdelta as a novel and selective regulator of Ag receptor-induced lytic granule polarization in mouse CD8+ T cells.
- Published
- 2007
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16. Activation of primary T lymphocytes results in lysosome development and polarized granule exocytosis in CD4+ and CD8+ subsets, whereas expression of lytic molecules confers cytotoxicity to CD8+ T cells.
- Author
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Shen DT, Ma JS, Mather J, Vukmanovic S, and Radoja S
- Subjects
- Animals, Apoptosis immunology, CD4-Positive T-Lymphocytes metabolism, CD8-Positive T-Lymphocytes metabolism, Cell Polarity immunology, Cell Survival immunology, Cytoplasmic Granules enzymology, Cytoplasmic Granules metabolism, Exocytosis immunology, Lymphocyte Activation immunology, Mice, Mice, Inbred C57BL, Perforin, Receptors, Antigen, T-Cell immunology, CD4-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes immunology, Cytoplasmic Granules immunology, Granzymes biosynthesis, Lysosomes immunology, Membrane Glycoproteins biosynthesis, Pore Forming Cytotoxic Proteins biosynthesis
- Abstract
Lytic granule exocytosis is the major cytotoxic mechanism used by CD8(+) cytotoxic lymphocytes. CD8(+) T cells acquire this effector function in the process characterized by lysosomal biogenesis, induction of expression of cytolytic molecules, and their selective sorting into the lysosomal vesicles. However, temporal relation of these differentiation stages during T cell activation has not been defined precisely. Also, although CD4(+) T cells typically do not express lytic molecules as a consequence of activation, and therefore, do not acquire granule exocytosis-mediated lytic function, it is not clear whether CD4(+) T cells are able to degranulate. By using in vitro TCR stimulation of primary mouse lymphocytes, we found that polyclonally activated CD4(+) T cells degranulate upon TCR ligation and polarize enlarged lysosomal granules in response to target cell recognition, despite the lack of granule exocytosis-mediated cytotoxicity. Upon TCR stimulation, resting CD8(+) T cells rapidly express lytic molecules and acquire potent lytic function early in activation. Maximal cytolytic potential, however, depends on enlargement of lysosomal granules during the subsequent activation stages. Thus, polyclonal TCR stimulation of resting T cells results in development of lysosomal granules and their release upon TCR engagement in CD4(+) and CD8(+) T cells, but only CD8(+) T cells acquire lytic function as a result of induction of expression of lytic molecules.
- Published
- 2006
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17. [Comparative study of warfarin and aspirin for stroke prevention in elderly patients with atrial fibrillation].
- Author
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Han W, Shen DT, and Wang YM
- Subjects
- Aged, Anticoagulants therapeutic use, Aspirin therapeutic use, Atrial Fibrillation complications, China epidemiology, Female, Humans, Male, Retrospective Studies, Stroke complications, Stroke epidemiology, Treatment Outcome, Atrial Fibrillation drug therapy, Stroke prevention & control, Warfarin therapeutic use
- Abstract
Objective: To analyze current stroke prevention measures for elderly patients with atrial fibrillation., Methods: A retrospective analysis was conducted of the clinical records of elderly patients with atrial fibrillation treated in our hospital within the recent 5 years. The distribution of high risk factors for different age levels was studied, and the incidence of stroke and complications such as hemorrhage were compared between patients treated with warfarin and aspirin therapy., Results: Compared with patients of 65 to 75 years old, the incidence of complications with other high risk factors was increased in advanced age group (over 75 years). Of these patients, 19.0% were treated with warfarin and 73.4% with aspirin. Compared with the aspirin group, stroke incidence was decreased significantly in warfarin group, which had simultaneously increased nonfatal hemorrhage., Conclusion: Warfarin can be more effective than aspirin for stroke prevention in elderly patients with atrial fibrillation, but in clinical practice, the usage rate of warfarin still remains low with insufficient monitoring.
- Published
- 2006
18. [Effects of aging and hypoxia on the proliferation of cultured rat pulmonary arterial smooth muscle cells].
- Author
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Shen DT, Fu XY, Huang QB, Huang XL, and Wang SW
- Subjects
- Animals, Cell Cycle, Cell Division, Cells, Cultured, Female, Flow Cytometry, Immunohistochemistry, Male, Proliferating Cell Nuclear Antigen analysis, Rats, Rats, Sprague-Dawley, Thymidine metabolism, Aging pathology, Cell Hypoxia physiology, Muscle, Smooth, Vascular cytology, Pulmonary Artery cytology
- Abstract
Objective: To study the effects of aging and hypoxia on the proliferative behavior of cultured pulmonary arterial smooth muscle cells (PASMCs)., Methods: PASMCs isolated from aged (18-24 months) and young (3-4 months) rats were divided, according to the different treatments the cells were subjected to, into young and aged normoxic groups (groups A and B) and young and aged hypoxic groups (groups C and D) respectively. MTT cell proliferation assay, 3H-TdR incorporation assay, flow cytometriy and immunocytochemical analysis were respectively employed to observe the proliferative behavior., Results: Compared with the cells from young rats, PASMCs from aged rats had a higher proliferation rate, more 3H-TdR incorporation, increased mitotic cell ratio, reduced amount of the total protein, and elevated content of proliferating cell nuclear antigen (PCNA). In comparison with normoxic condition, hypoxia elicited higher proliferation rate of the cells with inhibition of 3H-TdR incorporation that was subsequently increased. Higher percentage of mitotic cells, less total protein amount and increased PCNA were also observed in response to hypoxia., Conclusions: Aging and hypoxia may directly induce PASMC proliferation, and in aging PASMCs, the proliferation is the most obvious in response to hypoxic stimulation.
- Published
- 2003
19. Malignant catarrhal fever virus. Characterization of a United States isolate and development of diagnostic assays.
- Author
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Li H, Shen DT, O'Toole D, Davis WC, Knowles DP, Gorham JR, and Crawford TB
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- Animals, Antibodies, Monoclonal, Antigens, Viral biosynthesis, Base Sequence, Cattle, Cell Line, DNA Primers, Deer, Herpesviridae genetics, Herpesviridae physiology, Malignant Catarrh virology, Molecular Sequence Data, Ruminants, Sheep, United States, Viral Proteins analysis, Virus Replication, Antibodies, Viral blood, Enzyme-Linked Immunosorbent Assay, Herpesviridae isolation & purification, Malignant Catarrh diagnosis, Polymerase Chain Reaction
- Abstract
Malignant catarrhal fever (MCF) is a severe lymphoproliferative disease of certain domestic and wild ruminants. Two distinct but closely related viruses cause clinically indistinguishable syndromes in susceptible ruminant species: wildebeest-associated MCF virus (WA-MCFV) and sheep-associated MCF virus (SA-MCFV). Neither the pathogenesis nor the epidemiology of SA-MCF is understood, primarily because of a lack of adequate detection methods for the etiologic agent or antibody against that agent. Work designed to develop these tests has been under way in our laboratory. To obtain basic information about the virus, the in vitro growth properties of a US isolate of MCF virus were studied and its major viral proteins identified and characterized by a panel of monoclonal antibodies generated against the isolate. A monoclonal antibody to a broadly conserved epitope of MCF virus was identified, and a competitive-inhibition ELISA (CI-ELISA) was developed for detection of anti-MCF antibody in sheep and other ruminants. The monoclonal antibody (15-A) reacted with an epitope located on a glycoprotein complex, which was present in all isolates of MCF virus examined. Antibody from a wide variety of ruminants infected with MCF virus of both sheep and wildebeest origin competed with the monoclonal antibody 15-A for the epitope, which was not present on 14 other common ruminant viruses. The assay detected antibody in inapparently infected sheep, and in cattle, deer, and bison with clinical MCF. A PCR assay for DNA of the sheep-associated virus was developed, based on previously reported primers. Comparative studies demonstrated that the CI-ELISA was specific for MCFV antibody and that the PCR was more reliable for diagnosis of clinical MCF.
- Published
- 1996
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20. Prevalence of antibody to malignant catarrhal fever virus in wild and domestic ruminants by competitive-inhibition ELISA.
- Author
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Li H, Shen DT, Jessup DA, Knowles DP, Gorham JR, Thorne T, O'Toole D, and Crawford TB
- Subjects
- Age Factors, Animals, Animals, Domestic, Animals, Wild, Binding, Competitive, Enzyme-Linked Immunosorbent Assay veterinary, Malignant Catarrh immunology, Prevalence, United States epidemiology, Antibodies, Viral blood, Herpesviridae immunology, Malignant Catarrh epidemiology, Ruminants
- Abstract
A competitive-inhibition ELISA (CI-ELISA), based on a monoclonal antibody to an epitope conserved among malignant catarrhal fever virus (MCFV) strains of both wildebeest and sheep origin, was used to determine the prevalence of antibody to MCFV in selected domestic and wild ruminants, both free-ranging and captive, from the USA. We evaluated 2528 sera from 14 species between 1990 and 1995, including 80 pronghorn antelope (Antilocapra americana), 339 bighorn sheep (Ovis canadensis), 103 biston (Bison bison), 17 black-tailed deer (Odocoileus hemionus columbianus), 395 domestic cattle (Bos taurus), 291 domestic goats (Capra hircus), 680 domestic sheep (Ovis ammon), 323 elk (Cervus elaphus), 41 llamas (Lama glama), 21 mouflon sheep (Ovis musimon), 54 mountain goats (Oreamnos americanus), 101 mule deer (Odocoileus hemionus), 20 muskox (Ovibos moschatus), and 63 white-tailed deer (Odocoileus virginianus). A high seroprevalence (37 to 62%) was observed in domestic sheep, domestic goats, muskox, and some bighorn sheep populations. Seroprevalence in these species was generally age-related: a very low seroprevalence was present in these animals under one year of age. A low seroprevalence (2% to 13%) was found in clinically-susceptible species such as domestic cattle, deer, elk and bison, supporting the concept that significant numbers of non-lethal infections occur among clinically susceptible ruminants.
- Published
- 1996
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21. Investigation of sheep-associated malignant catarrhal fever virus infection in ruminants by PCR and competitive inhibition enzyme-linked immunosorbent assay.
- Author
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Li H, Shen DT, O'Toole D, Knowles DP, Gorham JR, and Crawford TB
- Subjects
- Animals, Animals, Newborn, Antibodies, Viral blood, Base Sequence, Bluetongue prevention & control, Bluetongue virology, Bluetongue virus isolation & purification, Cattle, Cattle Diseases prevention & control, Cattle Diseases virology, DNA Primers genetics, DNA, Viral genetics, DNA, Viral isolation & purification, Deer, Evaluation Studies as Topic, Female, Molecular Sequence Data, Polymerase Chain Reaction statistics & numerical data, Pregnancy, Sensitivity and Specificity, Sheep, Sheep Diseases prevention & control, Sheep Diseases virology, Bluetongue diagnosis, Bluetongue virus genetics, Bluetongue virus immunology, Cattle Diseases diagnosis, Enzyme-Linked Immunosorbent Assay methods, Polymerase Chain Reaction methods, Sheep Diseases diagnosis
- Abstract
Development of control measures for the gammaherpesviral disease of cattle known as sheep-associated malignant catarrhal fever (SA-MCF) has been hampered by a lack of accurate diagnostic tests either for the causative virus or for antibody against that virus. A recently developed competitive-inhibition enzyme-linked immunosorbent assay (CI-ELISA) for the detection of antibody to malignant catarrhal fever (MCF) virus (MCFV) in ruminants based on a monoclonal antibody to a widely conserved epitope of MCFV (H. Li, D. T. Shen, D. P. Knowles, J. R. Gorham, and T. B. Crawford, J. Clin. Microbiol. 32:1674-1679, 1994) and a PCR assay based on previously reported primers (S. I. F. Baxter, I. Pow, A. Bridgen, and H. W. Reid, Arch. Virol. 132:145-159, 1993) were used to detect anti-MCFV antibody and SA-MCFV DNA in sheep and other ruminants. The PCR amplified a specific 238-bp SA-MCFV genomic DNA fragment from peripheral blood lymphocytes of adult sheep and other ruminants with clinical MCF. Of 144 samples from randomly selected healthy adult sheep, 143 (99%) were positive by PCR and 136 (94%) were positive by CI-ELISA. The agreement between the two assays exceeded 95%. Of nine samples collected from cattle and deer with clinical MCF of apparent sheep origin, seven were CI-ELISA positive and all 9 were PCR positive. Among 59 serum samples from presuckling lambs, none contained antibody detectable by CI-ELISA. After suckling, maternal anti-MCFV antibody was detectable for about 10 +/- 3 weeks. Although all colostrum and milk samples from infected ewes were strongly PCR positive, the appearance of detectable SA-MCFV DNA in lambs was correlated generally with antibody patterns, which suggests that the natural infection event in sheep may not occur during the perinatal period but occurs sometime later in life.
- Published
- 1995
- Full Text
- View/download PDF
22. Identification and characterization of the major proteins of malignant catarrhal fever virus.
- Author
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Li H, Shen DT, Davis WC, Knowles DP, Gorham JR, and Crawford TB
- Subjects
- Animals, Antibodies, Monoclonal immunology, Cattle, Glycosylation, Immune Sera immunology, Mice, Mice, Inbred BALB C, Precipitin Tests, Sheep, Viral Proteins immunology, Gammaherpesvirinae chemistry, Malignant Catarrh virology, Viral Proteins analysis
- Abstract
Malignant catarrhal fever virus (MCFV), a gamma-herpesvirus, causes a severe inflammatory and lymphoproliferative disease of cattle and other susceptible ruminants. Polyclonal antisera and monoclonal antibodies (MAbs) to the Minnesota isolate of MCFV were produced and used to examine the characteristics of the viral proteins. Immunoprecipitation of antigens of the Minnesota isolate of MCFV with polyclonal antisera revealed at least 11 proteins with molecular masses ranging from 17 kDa to 145 kDa. Among 279 candidate anti-MCFV hybridomas, 14 were selected and clustered into six groups on the basis of the patterns of reactivity to viral proteins in immunoprecipitation and immunoblot. The group I MAbs exhibited strong neutralizing activity and recognized a glycosylation-dependent conformational epitope on a 110 kDa protein. The MAbs in group II bound a non-neutralizing conformational epitope on a 130 kDa non-glycosylated protein. A glycosylated protein complex of 115/110/105/78/45 kDa moieties was identified by the MAbs in group III. The MAbs in groups IV, V and VI reacted with non-glycosylated proteins of 36/34 kDa, 24 kDa and 17 kDa, respectively. Comparison of three MCFV isolates [the Minnesota isolate, the Austrian isolate (Au-732) and the African prototype isolate (WC-11)] revealed no apparent differences in immunoprecipitation patterns with the single exception that the 110 kDa protein of WC-11 was slightly smaller than its counterpart in the Minnesota isolate.
- Published
- 1995
- Full Text
- View/download PDF
23. Competitive inhibition enzyme-linked immunosorbent assay for antibody in sheep and other ruminants to a conserved epitope of malignant catarrhal fever virus.
- Author
-
Li H, Shen DT, Knowles DP, Gorham JR, and Crawford TB
- Subjects
- Animals, Antibodies, Monoclonal, Antibody Specificity, Cattle, Deer, Enzyme-Linked Immunosorbent Assay methods, Epitopes isolation & purification, Fluorescent Antibody Technique veterinary, Sensitivity and Specificity, Sheep, Antibodies, Viral isolation & purification, Conserved Sequence, Enzyme-Linked Immunosorbent Assay veterinary, Epitopes genetics, Gammaherpesvirinae immunology, Malignant Catarrh virology
- Abstract
Malignant catarrhal fever (MCF) is a severe, usually fatal, acute systemic disease syndrome of certain domestic and wild ruminants caused by members of the family Gammaherpesvirinae. Two distinct but closely related viruses cause clinically indistinguishable syndromes: one that is indigenous to the widebeest and the other that apparently is indigenous to domestic sheep. Neither the pathogenesis nor the epidemiology of sheep-associated MCF (SA-MCF) is understood, primarily because of a lack of adequate detection methods for the etiologic agent or antibody against it. No acceptably documented isolates of SA-MCF virus have been reported, and existing antibody assays suffer from significant cross-reactivity with other viruses. As a basis for a specific serologic assay, an attempt was made to identify an epitope conserved among all isolates of MCF viruses, by using a monoclonal antibody (MAb) produced against a previously reported U.S. isolate of MCF virus. A MAb (15-A) which bound a conserved epitope present on all four isolates of MCF virus examined was found. MAb 15-A did not react with eight common sheep and goat viruses or five common bovine viruses. Immunoprecipitation revealed that the 15-A epitope was located on the viral glycoprotein complex, with molecular masses of 115, 110, 105, 78, and 45 kDa. Sera from experimentally and naturally infected animals which yielded a similar glycoprotein complex immunoprecipitation pattern competed with MAb 15-A for its epitope. A competitive inhibition enzyme-linked immunosorbent assay (ELISA) based on MAb 15-A was therefore developed. The assay detected antibody in inapparently infected sheep and in cattle, deer, and bison with clinical MCF. Of the 149 serum samples from sheep associated with MCF outbreaks, 88 (55%) were seropositive by competitive inhibition ELISA.
- Published
- 1994
- Full Text
- View/download PDF
24. Molecular cloning and physical mapping of bovine herpesvirus 4 strain DN 599 and comparison with two American field-isolates.
- Author
-
Shen DT, Burger D, Tong GZ, and Gorham JR
- Subjects
- Animals, Cloning, Molecular, DNA, Viral genetics, Deoxyribonuclease BamHI, Deoxyribonuclease EcoRI, Deoxyribonuclease HindIII, Molecular Weight, Restriction Mapping, Cattle microbiology, Herpesviridae genetics
- Abstract
Ninety four percent of the genome of bovine herpesvirus 4 (BHV-4) strain DN 599 was cloned and a physical map was constructed by Southern blot analysis using a library of cloned fragments cleaved with the 3 restriction enzymes (Eco RI, Bam HI, and Hin dIII). The genome length was estimated to be 156.5 kbp +/- 0.7. The genome comprises a region of unique segment (114 kbp) and two flanking segments containing tandem repeats. The size of each repeat was approximately 2.35 kbp and each repeat contained one Eco RI site and two Bam HI sites. We also examined two recent American field-isolates of BHV-4 and compared the Eco RI maps of the two isolates with that of DN 599. We observed the following: (1) insertions or deletions of restriction sites at the periphery of the unique segment; (2) variation in the lengths of junction fragments; (3) variations in the lengths of hypermolar Eco RI fragments containing the repeats; and (4) the Eco RI map of one of the American field-isolates resembles the BHV-4 "Movar type" of Europe.
- Published
- 1992
- Full Text
- View/download PDF
25. Characterization of monoclonal antibodies to bovine herpesvirus type I, Los Angeles strain.
- Author
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Shen DT, Burger D, Li ZQ, and Gorham JR
- Subjects
- Animals, Antibodies, Monoclonal analysis, Antibodies, Viral analysis, Antibodies, Viral immunology, Antigenic Variation, Cattle, Cell Line, Enzyme-Linked Immunosorbent Assay, Epitopes analysis, Fluorescent Antibody Technique, Immunoblotting, Molecular Weight, Neutralization Tests, Precipitin Tests, Serial Passage, Antibodies, Monoclonal immunology, Herpesvirus 1, Bovine immunology, Infectious Bovine Rhinotracheitis diagnosis
- Abstract
We produced monoclonal antibodies (mAbs) against bovine herpesvirus type 1 (BHV-1), Los Angeles strain, and then evaluated them as potential candidates for preparing diagnostic reagents. Of the 318 cell lines expressing antibodies to the virus, 60% (192) secreted IgG and 40% (126) secreted IgM. Twenty-six mAbs were selected based on enzyme-linked immunosorbent assay (ELISA) and virus neutralization (VN) titers and characterized by immunoprecipitation, immunofluorescence and immunoblots. The selected mAbs were assigned to one of four groups based on their immunoprecipitation patterns. Group A (4 mAbs) precipitated a complex of three glycoproteins with molecular weight (MW) 130 kDa, 72 kDa and 55 kDa, which presumably represented gI of BHV-1. Monoclonal antibodies of this group were highly reactive in ELISA but had low VN titers. Group B (4 mAbs) precipitated a glycoprotein with MW of 71 kDa (gIV). This group of mAbs had high VN titers. Group C (16 mAbs) precipitated a 97 kDa glycoprotein (gIII). Monoclonal antibodies of this group had high ELISA but low VN titers. Group D (2 mAbs) precipitated a double band of non-glycosylated proteins with MW of 37/32 kDa; these proteins could not be assigned to any of the antigens of BHV-1 previously described. ELISA and VN titers of this group of mAbs were low. To test the antigenic variability of the antigenic determinants which were recognized by these 4 groups of mAbs, we adapted Madin Darby bovine kidney cell-propagated BHV-1 Los Angeles strain to Crandell's feline kidney cell line. After the tenth passage in feline kidney cells, the epitopes on the 37/32 kDa peptide recognized by the mAbs group D were no longer detectable. Additional changes were noted in the electrophoretic mobility of the 130 kDa and 71 kDa glycoproteins (gI) identified by mAb of group A shifted downward. The 71 kDa glycoprotein (gIV) reactive with mAb group B and the 97 kDa (gIII) reactive with mAb group C remained stable. Since clone No. 191 of group B mAb was potent in ELISA, VN, immunoblots and immunofluorescence, and recognized an epitope which did not change under selective pressure, we feel that the mAb produced by this clone are a good candidate for the production of diagnostic reagents.
- Published
- 1991
- Full Text
- View/download PDF
26. Analysis of bovine herpesvirus 4 (DN 599) major antigens with monoclonal antibodies and polyclonal immune serum.
- Author
-
Li H, Shen DT, Burger D, Davis WC, and Gorham JR
- Subjects
- Animals, Antibodies, Monoclonal, Antibodies, Viral, Cattle, Cell Line, Electrophoresis, Polyacrylamide Gel, Glycoproteins immunology, Oxidation-Reduction, Precipitin Tests, Viral Proteins immunology, Antigens, Viral immunology, Herpesviridae immunology
- Abstract
Monoclonal antibodies (MAbs) and polyclonal immune sera were produced and used to identify the major antigens of bovine herpesvirus type 4 (BHV-4). SDS-polyacrylamide gel electrophoresis of immunoprecipitates of radiolabeled lysates from infected cells resolved 24 peptide bands varying from 12 kDa to over 300 kDa. Six peptides were identified as major viral antigens by immunoprecipitation. Based on the pattern of radioimmunoprecipitation, MAbs were assigned into four groups. Group 1 precipitated a tunicamycin-sensitive glycoprotein complex which contained six components (245, 190, 152, 123, and 48/46 kDa). Deglycosylation with endoglycosidase F revealed two peptides with Mr of 93 and 38 kDa as the basic peptides of the glycoprotein complex. In addition, a 115 kDa glycopeptide containing glycan-peptide bonds of mixed type was identified. Group 2 precipitated a non-glycosylated protein complex consisting of three monomers (33/31/30 kDa). Groups 3 and 4 reacted with single monomeric non-glycosylated peptides with Mr of 48 and 14 kDa, respectively. Although none of the MAbs exhibited significant neutralizing activity, some reacted strongly in immunosorbent and/or immunohistochemical assays, suggesting they may be good candidates for use in diagnostic assays.
- Published
- 1991
- Full Text
- View/download PDF
27. Viruria in dogs infected with canine distemper.
- Author
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Shen DT, Gorham JR, and Pedersen V
- Subjects
- Animals, Distemper prevention & control, Dogs, Viral Vaccines therapeutic use, Carnivora urine, Distemper urine, Distemper Virus, Canine analysis, Ferrets urine
- Published
- 1981
28. Contact transmission of distemper virus in ferrets.
- Author
-
Shen DT and Gorham JR
- Subjects
- Animals, Dogs, Carnivora, Distemper transmission, Ferrets
- Abstract
Distemper virus was transmitted when infected donor ferrets were placed with susceptible ferrets for various contact periods. Distemper was more likely to be transmitted during the later stages of the disease. A positive correlation was found between the length of contact time and the acquisition of infection.
- Published
- 1978
29. Comparison of an enzyme-linked immunosorbent assay and a complement-fixation test for the detection of IgG to bovine herpesvirus type 4 (bovine cytomegalovirus).
- Author
-
Guo WZ, Shen DT, Evermann JF, and Gorham JR
- Subjects
- Animals, Complement Fixation Tests veterinary, Enzyme-Linked Immunosorbent Assay, Female, Male, Antibodies, Viral analysis, Cattle microbiology, Cytomegalovirus immunology, Immunoglobulin G analysis
- Abstract
An indirect ELISA for the detection of bovine immunoglobulin to bovine herpesvirus type 4 (BHV-4) was developed. Three methods of antigen preparation were compared. They included (1) BHV-4-infected Madin Darby bovine kidney (MDBK) cells treated with glycine and then frozen and thawed, (2) BHV-4-infected MDBK cells treated with glycine and then sonicated, and (3) BHV-4-infected MDBK cells treated with a detergent. The antigen preparation that gave the highest reactivity was the first method. We obtained serum samples from 178 cattle in the field and assayed the serum by ELISA and the complement-fixation (CF) test. Eighty-six percent (153) of the serum samples were positive by ELISA, and 70% (124) were positive by the CF test. The ELISA had a higher degree of sensitivity than did the CF test. Also, the ELISA was specific, and the prevalence of BHV-4-infection was more common in beef and dairy herds than previously recognized.
- Published
- 1988
30. Enzyme-linked immunosorbent assay for detection of equine infectious anemia antibody to purified P26 viral protein.
- Author
-
Shen DT, Gorham JR, and McGuire TC
- Subjects
- Animals, Enzyme-Linked Immunosorbent Assay veterinary, Immunodiffusion veterinary, Antibodies, Viral analysis, Horses immunology, Infectious Anemia Virus, Equine immunology, Viral Proteins immunology
- Abstract
An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of equine infectious anemia (EIA) antibody in horse sera. Purified P26 viral protein was the antigen; alkaline phosphatase linked to rabbit anti-horse immunoglobulin G was the conjugate. The ELISA detected EIA antibodies in horse sera as early as 11 to 14 days after experimental inoculations. There was full agreement between the results of ELISA and the agar-gel immunodiffusion tests on EIA proficiency test sera. The ELISA readily detected EIA antibody in horse sera that had weak positive reactions on agar-gel immunodiffusion.
- Published
- 1984
31. Failure to propagate equine infectious anemia virus in mosquitoes and Culicoides variipennis.
- Author
-
Shen DT, Gorham JR, Jones RH, and Crawford TB
- Subjects
- Animals, Equine Infectious Anemia transmission, Horses, Ceratopogonidae microbiology, Culicidae microbiology, Infectious Anemia Virus, Equine growth & development
- Abstract
Laboratory-colonized mosquitoes, Culex tarsalis, aedes aegypti, Culiseta inornata, and Anopheles free-borni, and the biting gnat, Culicoides variipennis, were exposed to equine infectious anemia virus. Exposure to the virus was by intrathoracic inoculation for mosquitoes and by oral ingestion of an infective blood meal through a membrane for C variipennis. After various intervals, groups of 15 to 20 insects were homogenized and inoculated into susceptible ponies. Positive immunodiffusion test results were used as criterion for equine infectious anemia infection in ponies. Virus was not detected in the 4 species of mosquitoes at 3, 6, 12, and 18 days after inoculation, or in C variipennis at 6, 8, 12, 14, 21, and 26 days after oral exposure to the virus.
- Published
- 1978
32. Using jet injection to vaccinate mink and ferrets against canine distemper, mink virus enteritis, and botulism, type C.
- Author
-
Shen DT, Gorham JR, Ryland LM, and Strating A
- Subjects
- Animals, Botulism prevention & control, Cats, Dogs, Vaccination methods, Botulism veterinary, Carnivora, Distemper prevention & control, Feline Panleukopenia prevention & control, Ferrets, Mink, Vaccination veterinary
- Published
- 1981
33. Diagnosis of naturally occurring Fasciola hepatica infections in cattle with an enzyme-linked immunosorbent assay.
- Author
-
Wescott RB, Farrell CJ, and Shen DT
- Subjects
- Animals, Cattle, Cattle Diseases epidemiology, Fasciola hepatica, Fascioliasis diagnosis, Fascioliasis epidemiology, Feces parasitology, Parasite Egg Count veterinary, Washington, Cattle Diseases diagnosis, Enzyme-Linked Immunosorbent Assay veterinary, Fascioliasis veterinary, Immunoenzyme Techniques veterinary
- Abstract
Sera from 100 herds of cattle located in the state of Washington were examined with an enzyme-linked immunosorbent assay for antibody to Fasciola hepatica in a screening procedure that included 5 to 10 samples/herd. Twenty-eight herds contained infected cattle and F hepatica was most prevalent in 3 distinct geographic areas. Subsequent retesting of all sera available from 14 herds (mean of 109 samples/herd) revealed that the screening procedure correctly detected 7 of 7 operations in which greater than 40% of samples were positive or suspect and 3 of 3 operations in which 12% to 13% of the samples were positive or suspect. One of 3 herds considered negative after screening was found to contain a few (7%) positive samples and 1 herd considered possibly infected was negative on retest. These results were compared with those obtained by fecal examination for F hepatica eggs in 9 of the 14 herds. A good correlation (5 of 5) was found in which a high percentage (48% to 85%) of sera were positive or suspect. Fasciola eggs were not found in samples from 2 herds with few (7% to 12%) positive or suspect sera or in 2 herds that were negative by an enzyme-linked immunosorbent assay.
- Published
- 1984
34. Evaluation of chemical disinfectants for aleutian disease virus of mink.
- Author
-
Shen DT, Leendertsen LW, and Gorham JR
- Subjects
- Chlorhexidine pharmacology, Ethanol pharmacology, Formaldehyde pharmacology, Glutaral pharmacology, Iodophors pharmacology, Sodium Hydroxide pharmacology, Sodium Hypochlorite pharmacology, Water pharmacology, Aleutian Mink Disease Virus drug effects, Disinfectants pharmacology, Viruses, Unclassified drug effects
- Abstract
Nine chemicals and commercial disinfectants were tested for inactivation of Aleutian disease virus of mink. In the presence of distilled water, a commercial disinfectant (O-Syl), halogen derivatives (iodophor and sodium hypochlorite), and glutaraldehyde (2.0%) inactivated 4 log10 (based on 0.25 ml) of the virus within 10 minutes at 23 C. Formalin (2.0%) and O-Syl were slower to inactivate the virus, but achieved a 4 log10 reduction in titer by 30 minutes' contact time. In the presence of 10% bovine serum, formalin (1.0%), O-Syl, and sodium hydroxide (0.5%) achieved a 4 log10 reduction within 10 minutes. All agents tested had some virucidal effect.
- Published
- 1981
35. Precipitating antibodies in experimental visna and natural progressive pneumonia of sheep.
- Author
-
Klein JR, Martin J, Griffing S, Nathanson N, Gorham J, Shen DT, Petursson G, Georgsson G, Palsson PA, and Lutley R
- Subjects
- Animals, Complement Fixation Tests veterinary, Immunodiffusion veterinary, Neutralization Tests, Sheep, Time Factors, Antibodies, Viral biosynthesis, Pneumonia, Progressive Interstitial, of Sheep immunology, Sheep Diseases immunology, Visna-maedi virus immunology
- Abstract
Serological responses of Icelandic sheep experimentally infected with visna virus (vv) were contrasted with responses in American Targhee sheep naturally infected with progressive pneumonia virus (PPV). Precipitating antibodies assayed by immunodiffusion were compared with the neutralising and complementing fixing antibody response. In experimental infections with vv, complement fixing and neutralising antibodies appeared early after infection and rose to high levels in all sheep, while precipitating antibodies were detected only at minimal titre. In natural infections with PPV, immune responses were less consistent and precipitating antibodies were detected more frequently than complement fixing or neutralising antibodies against PPV. These results may suggest important biological differences between the lytic fibroblast-tropic virus strains used for experimental infection of Icelandic sheep and the nonlytic macrophage-tropic strains of PPV circulating in nature. Lytic strains evoke a brisk response against the viral glycoprotein with high titre neutralising antibody while nonlytic strains induce a less consistent response to the glycoprotein.
- Published
- 1985
36. Survival of pathogenic distemper virus at 5C and 25C.
- Author
-
Shen DT and Gorham JR
- Subjects
- Animals, Carnivora, Distemper Virus, Canine pathogenicity, Temperature
- Published
- 1980
37. An outbreak of tularemia in mink.
- Author
-
Henson JB, Gorham JR, and Shen DT
- Subjects
- Animals, Disease Outbreaks veterinary, Liver pathology, Lung pathology, Tularemia microbiology, Tularemia pathology, Tularemia transmission, Mink, Tularemia veterinary
- Abstract
An outbreak of tularemia in farm raised mink is reported. Twenty-six of approximately 5000 mink succumbed within a 10 day period. Prodromal signs were minimal. Necropsy revealed necrotic nodules scattered in the parenchyma of the lungs, liver, spleen, and mesenteric lymph nodes. Francisella tularensis was isolated from spleens, livers and lungs.
- Published
- 1978
38. Serologic survey of prevalence of ovine progressive pneumonia in Idaho range sheep.
- Author
-
Gates NL, Winward LD, Gorham JR, and Shen DT
- Subjects
- Animals, Antibodies, Viral analysis, Idaho, Immunodiffusion, Pneumonia, Progressive Interstitial, of Sheep immunology, Sheep, Visna-maedi virus immunology, Pneumonia, Progressive Interstitial, of Sheep epidemiology
- Abstract
Blood samples from 2,310 mature sheep in 3 Idaho range flocks were examined by agar gel immunodiffusion to determine the prevalence of ovine progressive pneumonia. The prevalence ranged from 58% for all ages combined in one flock to 90% of cull ewes in another flock. Age-specific prevalence rates increased from 16% in yearlings to 83% in ewes greater than or equal to 7 years old. Rambouillet sheep had a significantly (P less than 0.01) lower prevalence than sheep of 5 other breeds, whereas one-half Finnsheep crosses had a significantly (P less than 0.01) higher prevalence than sheep of other breeds. Within breed and age, there was no significant difference in reproductive performance between seropositive and seronegative ewes.
- Published
- 1978
39. Transforming activity of human nasopharyngeal carcinoma DNA.
- Author
-
Hu LF, Li XL, Jiang JQ, Yao J, Yu Y, Cao SL, Huang KM, Shen DT, Wang LP, and Gu JR
- Subjects
- Animals, Base Sequence, Cell Line, DNA Restriction Enzymes metabolism, Deoxyribonuclease HindIII, Humans, Mice, Mice, Nude, Nucleic Acid Hybridization, Cell Transformation, Neoplastic, DNA, Neoplasm metabolism, Nasopharyngeal Neoplasms genetics, Transfection
- Abstract
NIH 3T3 cells were transfected with the DNAs from biopsy specimens of human nasopharyngeal carcinoma (NPC, EBV DNA positive) using calcium phosphate precipitation method. The malignant, transformed foci of NIH 3T3 cells have been observed and cloned. The hybridization of transfectant DNA digested by EcoRI with total human leukocyte DNA as probe was performed. The strong signal of smear comparing with NIH 3T3 DNA as control was observed. It was implied that the putative human transforming sequences had been integrated into transformed cells. Employing soft agar culture, the transformed cells can grow and form cell colonies. Following transfer, the foci were able to grow and adhere to a glass wall. These cells were easily agglutinated by con A. The cloned foci have been inoculated into nude mice with the formation of highly malignant sarcomas. In preliminary experiments for characterizing the transforming sequences, Ha-ras and Blym 1 were found in transfectants derived from one of the NPC DNA samples. It is implicated that these two oncogenes might be responsible for the acquisition of malignant phenotypic character of some human NPC. The further identification of oncogenes in NPC is currently in progress.
- Published
- 1986
40. Comparison of subcutaneous and intramuscular administration of a live attenuated distemper virus vaccine in ferrets.
- Author
-
Shen DT, Gorham JR, Evermann JF, and McKeirnan AJ
- Subjects
- Animals, Dogs, Injections, Intramuscular, Injections, Subcutaneous, Mink immunology, Vaccines, Attenuated administration & dosage, Viral Vaccines administration & dosage, Carnivora immunology, Distemper prevention & control, Distemper Virus, Canine immunology, Ferrets immunology, Vaccination veterinary
- Published
- 1984
- Full Text
- View/download PDF
41. An enzyme-linked immunosorbent assay for diagnosis of Fasciola hepatica infection in cattle.
- Author
-
Farrell CJ, Shen DT, Wescott RB, and Lang BZ
- Subjects
- Animals, Antigens isolation & purification, Cattle, Fasciola hepatica immunology, Fascioliasis diagnosis, Cattle Diseases diagnosis, Enzyme-Linked Immunosorbent Assay, Fascioliasis veterinary, Immunoenzyme Techniques
- Abstract
An enzyme-linked immunosorbent assay (ELISA) was investigated for the diagnosis of Fasciola hepatica infection in cattle. Studies included examination of 4 antigen preparations: freshly collected fluke antigen (FFA), dead fluke antigen (DFA), lyophilized fluke antigen (LFA), and partially purified antigen (PPA) for activity and use of an ELISA with FFA and LFA for diagnosis of experimentally and naturally occurring fascioliasis in cattle. The ELISA, using FFA, detected F hepatica antibody in calves as early as 4 weeks after exposure to this parasite. The DFA exhibited slightly less activity, and LFA did not have diagnostic value until 9 to 10 weeks after exposure. The PPA produced high background readings with noninfected control sera and was not considered sufficiently specific for further use. The long incubation and short incubation ELISA procedures can be used for diagnostic work. Both were equally sensitive, with optical density readings of known positive sera routinely 2.5 times those of sera from normal controls. The repeatability of these tests was also excellent, and only slight variation in optical density was observed in ELISA was performed on representative known positive and negative sera with similar reagents in replicate tests.
- Published
- 1981
42. Antigen requirements and specificity of enzyme-linked immunosorbent assay for detection of canine IgG against canine distemper viral antigens.
- Author
-
Bernard SL, Shen DT, and Gorham JR
- Subjects
- Animals, Dogs, Enzyme-Linked Immunosorbent Assay veterinary, Epitopes, Neutralization Tests, Viral Vaccines immunology, Antibodies, Viral analysis, Antigens, Viral immunology, Antigens, Viral isolation & purification, Distemper immunology, Distemper Virus, Canine immunology, Immunoglobulin G analysis
- Abstract
An enzyme-linked immunosorbent assay (ELISA) was developed for detection of specific immunoglobulin G (IgG) against canine distemper virus (CDV) antigens. Sucrose gradient separation of viral and cellular proteins was required to produce coating antigens for the ELISA. The specificity of the ELISA was demonstrated by blocking CDV-positive canine sera with CDV-specific antisera produced in goats and rabbits and adsorption of positive sera with CDV antigens. A comparison of the ELISA with the serum-neutralization technique for the detection of CDV antibodies was conducted. Anti-CDV IgG was detected in conventional dogs as early as 6 days after inoculation with a commercial vaccine to CDV. Paired sera from the immunized dogs were evaluated by both techniques and a statistically (P less than 0.01) significant agreement between the ELISA and the serum-neutralization technique was shown (r = 0.6121, n = 75).
- Published
- 1982
43. Detection of mink enteritis virus in mink feces, using enzyme-linked immunosorbent assay, hemagglutination, and electron microscopy.
- Author
-
Shen DT, Ward AC, and Gorham JR
- Subjects
- Animals, Enzyme-Linked Immunosorbent Assay, Hemagglutination Tests veterinary, Microscopy, Electron, Feces microbiology, Feline Panleukopenia Virus analysis, Mink microbiology, Parvoviridae analysis
- Abstract
Twenty-five mink were inoculated with mink enteritis virus (MEV). Fecal specimens were collected daily and were simultaneously evaluated for MEV antigen by use of a direct enzyme-linked immunosorbent assay (ELISA), hemagglutination (HA), and electron microscopy. Results of the evaluations indicated that MEV was shed in the feces on postinoculation days 5 and 6. The virus was not detectable by ELISA or HA after postinoculation day 6, although viruses were found in reduced numbers by use of electron microscopy. The ELISA was specific for MEV, and the sensitivity of the ELISA for MEV was comparable with that of HA.
- Published
- 1986
44. Inactivation of equine infectious anemia virus by chemical disinfectants.
- Author
-
Shen DT, Crawford TB, Gorham JR, and McGuire TC
- Subjects
- Cells, Cultured, Chlorhexidine pharmacology, Glutaral pharmacology, Infectious Anemia Virus, Equine growth & development, Infectious Anemia Virus, Equine immunology, Iodophors pharmacology, Sodium Hypochlorite pharmacology, Disinfectants pharmacology, Infectious Anemia Virus, Equine drug effects
- Abstract
Twelve chemicals and commercial disinfectants were tested for inactivation of equine infectious anemia virus. In the presence of 10% bovine serum, all chemicals inactivated 4 log10 (based on 0.1 ml) of the virus within 5 minutes at 23 C. A reduction of at least 4 log10 was observed when the virus was exposed for 1 minute to substituted phenolic disinfectants (3 commercial preparations and sodium orthophenylphenate), halogen derivatives (iodophor and sodium hypochlorite), chlorhexidine, and 70% ethanol. Sodium hydroxide (5%), 2% formalin, and 2% glutaraldehyde were slower to inactivate the virus, but achieved 4 log10 reduction in titer by 5 minutes' contact time. The susceptibility of the equine infectious anemia virus to chemical disinfectants is similar to that of other enveloped viruses.
- Published
- 1977
45. Comparison of the lesions of Aleutian disease in mink and hypergammaglobulinemia in ferrets.
- Author
-
Ohshima K, Shen DT, Henson JB, and Gorham JR
- Subjects
- Aleutian Mink Disease immunology, Aleutian Mink Disease Virus immunology, Animals, Antibodies, Viral analysis, Blood Vessels pathology, Hypergammaglobulinemia pathology, Kidney pathology, Lung pathology, Lymph Nodes pathology, Mink, Spleen pathology, Aleutian Mink Disease pathology, Carnivora, Ferrets, Hypergammaglobulinemia veterinary
- Abstract
Gross and microscopic lesions of Aleutian disease (AD) in mink and hypergammaglobulinemia in ferrets were compared. Both conditions were characterized by widespread proliferation of plasma cells, but proliferation was more prominent in mink infected with AD. Arteritis did not occur in hypergammaglobulinemic ferrets. Minimal or no glomerular alterations occurred in infected ferrets, but were severe in mink infected with AD. Bile duct proliferation was more prominent in diseased mink. Tissue alterations suggested that AD in Aleutian genotype mink is more rapidly progressive than is AD in ferrets, causing overt clinical disease and death. In contrast, hypergammaglobulinemia in ferrets appeared to progress more slowly, with little clinical evidence of disease. This is probably the result of a paucity of glomerular lesions in ferrets. Possible mechanisms to explain the differences in the development of lesions are discussed.
- Published
- 1978
46. Microimmunodiffusion test for diagnosis of ovine progressive pneumonia.
- Author
-
Winward LD, Leendertsen L, and Shen DT
- Subjects
- Animals, Antigen-Antibody Reactions, Precipitin Tests, Sheep, Immunodiffusion methods, Pneumonia, Progressive Interstitial, of Sheep immunology
- Abstract
Two microimmunodiffusion tests (MIDT) for detection and measurement of ovine progressive pneumonia antibody are described. Substrates of various salt concentrations and pH were used to determine the optimal conditions for the tests. In comparisons between two MIDT and one macroimmunodiffusion test, sera from cull ewes were used. The MIDT require less reagents and were more responsive than the macroimmunodiffusion test. After extended incubation of the test materials, results in all three tests were comparable.
- Published
- 1979
47. A disease resembling mink distemper.
- Author
-
Shen DT and Gorham JR
- Subjects
- Animals, Distemper immunology, Dogs, Ferrets, Distemper diagnosis, Mink
- Published
- 1977
48. Efficacy of Corynebacterium pseudotuberculosis bacterin for the immunologic protection of sheep against development of caseous lymphadenitis.
- Author
-
LeaMaster BR, Shen DT, Gorham JR, Leathers CW, and Wells HD
- Subjects
- Animals, Corynebacterium Infections immunology, Corynebacterium Infections prevention & control, Lymphadenitis immunology, Lymphadenitis prevention & control, Sheep, Sheep Diseases immunology, Sheep Diseases microbiology, Bacterial Vaccines immunology, Corynebacterium immunology, Corynebacterium Infections veterinary, Lymphadenitis veterinary, Sheep Diseases prevention & control
- Abstract
The efficacy of a Corynebacterium pseudotuberculosis bacterin to protect sheep immunologically against development of caseous lymphadenitis was evaluated in controlled challenge-exposure experiments. Sixty-three mixed-breed, white-faced lambs were used. The lambs were 10 to 12 weeks old and were randomly assigned to 3 groups (21 lambs/group). Group 1 was vaccinated once, using 2 ml of a C pseudotuberculosis bacterin (given subcutaneously) in the right axillary region at the beginning of the study. Group 2 was vaccinated twice; the 1st vaccination was given at the same time that lambs in group 1 were vaccinated and the 2nd vaccination was given 4 weeks later. Group 3 (nonvaccinated controls) was given physiologic saline solution (2 ml, subcutaneously). Each lamb was challenge exposed (ie, given 2 ml of live Corynebacterium pseudotuberculosis inoculum [6 X 10(6) colony-forming units/ml], subcutaneously at 4 different sites) during the 20th week of the study. All lambs were killed and necropsied during week 33. The mean number of abscesses per lamb was 7 for group 1, 4 for group 2, and 32 for group 3. Significant differences in the size of the abscesses were not found between the groups. Results of the study indicated that the vaccine provided immunologic protection of lambs against challenge exposure to Corynebacterium pseudotuberculosis.
- Published
- 1987
49. The persistence of Aleutian disease virus in the mosquito Aedes fitchii.
- Author
-
Shen DT, Gorham JR, Harwood RF, and Padgett GA
- Subjects
- Animals, Feeding Behavior, Female, Intestines microbiology, Mink, Ovary microbiology, Salivary Glands microbiology, Species Specificity, Time Factors, Virus Replication, Viruses, Unclassified isolation & purification, Viruses, Unclassified pathogenicity, Aedes, Aleutian Mink Disease microbiology, Insect Vectors, Viruses, Unclassified growth & development
- Published
- 1973
- Full Text
- View/download PDF
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