15 results on '"Sim JC"'
Search Results
2. Mediating mechanism of posttraumatic growth as buffers of burnout and PTSD among nurses during the COVID-19 pandemic.
- Author
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Sim JC, Cha SK, and Im SY
- Subjects
- Humans, Female, Adult, Male, Surveys and Questionnaires, Nurses psychology, SARS-CoV-2, Social Support, Pandemics, Middle Aged, Adaptation, Psychological, COVID-19 psychology, Stress Disorders, Post-Traumatic psychology, Stress Disorders, Post-Traumatic epidemiology, Burnout, Professional psychology, Posttraumatic Growth, Psychological
- Abstract
Objective: The study aims to investigate factors that prevent burnout (BO) and symptoms of posttraumatic stress disorder (PTSD) while facilitating posttraumatic growth (PTG) among nurses combating the coronavirus disease 2019 (COVID-19) pandemic, with the purpose of validating the mediating effects of PTG., Methods: A total of 247 nurses who provided patient care during the COVID-19 pandemic were enrolled, and a questionnaire was used to measure BO, PTSD, and PTG, data on deliberate rumination, emotional expression, adaptive cognitive emotion regulation (CER), maladaptive CER, and social support. The mediation path models for the effects of the predictors on BO and PS through the mediation of PTG were analyzed using the R Lavaan package., Results: The results showed that deliberate rumination, emotional expression, and adaptive CER significantly increased PTG, while PTG significantly reduced BO and PTSD symptoms (PSs). However, maladaptive CER did not have a significant effect on PTG and only had significant direct effects on BO and PS. Bootstrapping confirmed that PTG significantly mediated the effects of all predictors. It partially mediated the effects of deliberate rumination and adaptive CER and completely mediated the effects of emotional expression., Conclusion: Based on the results, it has been supported that deliberate rumination, emotional expression, and adaptive CER should be addressed as important variables in psychological interventions addressing nurses' adversities during the pandemic. These variables can prevent BO and PS by facilitating PTG., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sim, Cha and Im.)
- Published
- 2024
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3. The impact of COVID-19 on mental health and posttraumatic growth of Korean college students: a mixed method study examining the moderating role of coping flexibility and sense of community.
- Author
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Sim JC and Im SY
- Abstract
Introduction: In the context of the COVID-19 pandemic, which has led to complex psychological problems, it is important to examine the effect of coping flexibility and sense of community, because relying solely on specific coping strategies is ineffective, and the pandemic necessitates social cooperation., Methods: This study was divided into two parts. The first study used a quantitative research method(i.e., structural equation modeling) to test if coping flexibility and sense of community moderated the impact of COVID-19-related concerns on mental health (i.e., depression and anxiety) and posttraumatic growth among Korean college students. The second study used a qualitative research method for an in-depth examination of how Korean college students coped with the COVID-19 pandemic and if they achieved any positive change or growth. Given that the COVID-19 pandemic represents a situation distinct from what people have previously encountered, Study II was designed to examine the experiences of individuals during this exceptional period., Results: In the first study (Study I), coping flexibility was found to increase the impact of COVID-19-related concerns and difficulties on depression and anxiety. Conversely, a sense of community reduced the consequences of these overwhelming worries on depression and anxiety, while also expanding the impact of COVID-19-related disorders on posttraumatic growth. In the second study (Study II), the findings showed that the participants experienced various psychological consequences, including depression and anxiety, and distress in other aspects of their life, including disruptions in interpersonal relationships and college life. Nonetheless, the participants made efforts to cope with such difficulties and overcome the challenges together with the community. In fact, the pandemic improved their coping skills and expanded their value system and worldview., Conclusion: The study findings suggest that given the unique situation presented by the COVID-19 pandemic, a sense of community protected the mental well-being of Korean college students and facilitated their growth. This study emphasizes the necessity of promoting SOC to effectively cope with disaster situations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Sim and Im.)
- Published
- 2023
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4. Searching for an ideal cervical cancer screening model to reduce false-negative errors in a country with high prevalence of cervical cancer.
- Author
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Song T, Seong SJ, Lee SK, Kim BR, Ju W, Kim KH, Nam K, Sim JC, and Kim TJ
- Subjects
- Adult, Cervix Uteri pathology, Cervix Uteri virology, Cross-Sectional Studies, False Negative Reactions, Female, Humans, Middle Aged, Papanicolaou Test statistics & numerical data, Papillomaviridae, Papillomavirus Infections complications, Papillomavirus Infections diagnosis, Papillomavirus Infections epidemiology, Prevalence, Republic of Korea epidemiology, Sensitivity and Specificity, Uterine Cervical Neoplasms epidemiology, Uterine Cervical Neoplasms virology, Vaginal Smears statistics & numerical data, Uterine Cervical Dysplasia epidemiology, Uterine Cervical Dysplasia virology, Cervix Uteri diagnostic imaging, Early Detection of Cancer methods, Gynecology methods, Uterine Cervical Neoplasms diagnosis, Uterine Cervical Dysplasia diagnosis
- Abstract
The purpose of this study was to develop an ideal cervical cancer screening model to reduce false-negative errors in Korea where there is a high prevalence of cervical cancer. We conducted a cross-sectional study including 33,531 women who underwent routine cervical cancer screening in Korea. Colposcopic examinations were performed after abnormal results on their screening tests. Diagnostic capacities including sensitivity, specificity, and false-negative rate of each screening scenario were analysed at the CIN1 or worse (CIN1+) threshold with colposcopic biopsy results considered the gold standard. A total of 4117 women had valid results for Papanicolaou (Pap) cytology, human papilloma virus (HPV) tests, cervicography, and colposcopically directed biopsy were included in this study. The disease prevalence of CIN1+ was 38.1%. Pap-alone resulted in the highest false-negative rate of 46.9%, followed by HPV-alone at 25.1%, cervicography-alone at 18.7%, Pap/HPV-combined at 15.0%, Pap/cervicography-combined at 6.9% and Pap/HPV/cervicography-combined at 2.9% in a sample of 1570 women with CIN1+ lesions. Therefore, cervicography demonstrated excellent performance for the detection of CIN or cervical cancer and markedly reduced false-negative errors when used in combination with Pap cytology and HPV tests.IMPACT STATEMENT What is already known on this subject? False-negative rate of Pap smears is as high as approximately 40-50%. Limitations of the Papanicolaou (Pap) test have led to the development of new screening programmes for cervical cancer, such as combination screenings with human papillomavirus (HPV) tests or cervicography. What do the results of this study add? Pap-alone resulted in the highest false-negative rate of 46.9%, followed by HPV-alone at 25.1%, cervicography-alone at 18.7%, Pap/HPV-combined at 15.0%, Pap/cervicography-combined at 6.9% and Pap/HPV/cervicography-combined at 2.9% in a sample of 1570 women with CIN1+ lesions. What are the implications of these findings for clinical practice and/or further research? Cervicography demonstrated excellent performance for the detection of CIN or cervical cancer and markedly reduced false negative errors when used in combination with Pap cytology and HPV tests.
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- 2020
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5. Screening capacity and cost-effectiveness of the human papillomavirus test versus cervicography as an adjunctive test to Pap cytology to detect high-grade cervical dysplasia.
- Author
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Song T, Seong SJ, Lee SK, Kim BR, Ju W, Kim KH, Nam K, Sim JC, and Kim TJ
- Subjects
- Adult, Cervix Uteri diagnostic imaging, Cervix Uteri virology, Cost-Benefit Analysis, Female, Humans, Mass Screening methods, Middle Aged, Odds Ratio, Papillomaviridae, Prevalence, Republic of Korea epidemiology, Retrospective Studies, Sensitivity and Specificity, Uterine Cervical Neoplasms epidemiology, Uterine Cervical Neoplasms virology, Uterine Cervical Dysplasia epidemiology, Uterine Cervical Dysplasia virology, Mass Screening economics, Papanicolaou Test economics, Uterine Cervical Neoplasms diagnosis, Vaginal Smears economics, Uterine Cervical Dysplasia diagnosis
- Abstract
Objective: This study compared the screening capacities and cost-effectiveness of the human papillomavirus (HPV) test versus cervicography as an adjunctive test to Papanicolaou (Pap) cytology to detect high-grade cervical neoplasia in Korea, a country with a high prevalence of cervical cancer., Study Design: Of 33,531 Korean women who underwent cervicography as a screening test for cervical cancer between January 2015 and December 2016, we retrospectively analyzed the records of 4117 women who simultaneously or subsequently underwent Pap cytology, an HPV test, cervicography, and colposcopically directed biopsy. At a threshold of cervical intraepithelial neoplasia grade 2 or worse (CIN2+), based on colposcopic biopsy, we compared the diagnostic capacities and cost-effectiveness of these screening tools., Results: The CIN2+ prevalence was 10.8% (446 of 4117 women) and the positive rate of high-risk HPV was 61.0% (2511 of 4117 women). Cervicography as an adjunctive to Pap cytology was a more sensitive test (97.5% vs 93.7%) with a higher odds ratio (15.65 vs 5.86) than the HPV test for detection of CIN2+ (P-value = 0.003). Moreover, the cost of cervicography co-testing was 23% less than that of HPV co-testing, decreasing the cost per patient with CIN2+ lesions from $1474 to $1135., Conclusion: Cervicography and Pap co-testing had superior screening capacity and cost-effectiveness for detection of preinvasive cervical lesions than HPV and Pap co-testing and may be an effective and cost-saving screening strategy in clinical practice in country with a high prevalence of cervical cancer., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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6. Familial cortical dysplasia caused by mutation in the mammalian target of rapamycin regulator NPRL3.
- Author
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Sim JC, Scerri T, Fanjul-Fernández M, Riseley JR, Gillies G, Pope K, van Roozendaal H, Heng JI, Mandelstam SA, McGillivray G, MacGregor D, Kannan L, Maixner W, Harvey AS, Amor DJ, Delatycki MB, Crino PB, Bahlo M, Lockhart PJ, and Leventer RJ
- Subjects
- Child, Child, Preschool, Female, Humans, Male, Mutation, Pedigree, Signal Transduction, TOR Serine-Threonine Kinases, Epilepsies, Partial genetics, Epilepsy genetics, GTPase-Activating Proteins genetics, Malformations of Cortical Development, Group I genetics
- Abstract
We describe first cousin sibling pairs with focal epilepsy, one of each pair having focal cortical dysplasia (FCD) IIa. Linkage analysis and whole-exome sequencing identified a heterozygous germline frameshift mutation in the gene encoding nitrogen permease regulator-like 3 (NPRL3). NPRL3 is a component of GAP Activity Towards Rags 1, a negative regulator of the mammalian target of rapamycin complex 1 signaling pathway. Immunostaining of resected brain tissue demonstrated mammalian target of rapamycin activation. Screening of 52 unrelated individuals with FCD identified 2 additional patients with FCDIIa and germline NPRL3 mutations. Similar to DEPDC5, NPRL3 mutations may be considered as causal variants in patients with FCD or magnetic resonance imaging-negative focal epilepsy., (© 2015 American Neurological Association.)
- Published
- 2016
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7. Complete callosal agenesis, pontocerebellar hypoplasia, and axonal neuropathy due to AMPD2 loss.
- Author
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Marsh AP, Lukic V, Pope K, Bromhead C, Tankard R, Ryan MM, Yiu EM, Sim JC, Delatycki MB, Amor DJ, McGillivray G, Sherr EH, Bahlo M, Leventer RJ, and Lockhart PJ
- Abstract
Objective: To determine the molecular basis of a severe neurologic disorder in a large consanguineous family with complete agenesis of the corpus callosum (ACC), pontocerebellar hypoplasia (PCH), and peripheral axonal neuropathy., Methods: Assessment included clinical evaluation, neuroimaging, and nerve conduction studies (NCSs). Linkage analysis used genotypes from 7 family members, and the exome of 3 affected siblings was sequenced. Molecular analyses used Sanger sequencing to perform segregation studies and cohort analysis and Western blot of patient-derived cells., Results: Affected family members presented with postnatal microcephaly and profound developmental delay, with early death in 3. Neuroimaging, including a fetal MRI at 30 weeks, showed complete ACC and PCH. Clinical evaluation showed areflexia, and NCSs revealed a severe axonal neuropathy in the 2 individuals available for electrophysiologic study. A novel homozygous stopgain mutation in adenosine monophosphate deaminase 2 (AMPD2) was identified within the linkage region on chromosome 1. Molecular analyses confirmed that the mutation segregated with disease and resulted in the loss of AMPD2. Subsequent screening of a cohort of 42 unrelated individuals with related imaging phenotypes did not reveal additional AMPD2 mutations., Conclusions: We describe a family with a novel stopgain mutation in AMPD2. We expand the phenotype recently described as PCH type 9 to include progressive postnatal microcephaly, complete ACC, and peripheral axonal neuropathy. Screening of additional individuals with related imaging phenotypes failed to identify mutations in AMPD2, suggesting that AMPD2 mutations are not a common cause of combined callosal and pontocerebellar defects.
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- 2015
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8. ARID1B-mediated disorders: Mutations and possible mechanisms.
- Author
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Sim JC, White SM, and Lockhart PJ
- Abstract
Mutations in the gene encoding AT-rich interactive domain-containing protein 1B (ARID1B) were recently associated with multiple syndromes characterized by developmental delay and intellectual disability, in addition to nonsyndromic intellectual disability. While the majority of ARID1B mutations identified to date are predicted to result in haploinsufficiency, the underlying pathogenic mechanisms have yet to be fully understood. ARID1B is a DNA-binding subunit of the Brahma-associated factor chromatin remodelling complexes, which play a key role in the regulation of gene activity. The function of remodelling complexes can be regulated by their subunit composition, and there is some evidence that ARID1B is a component of the neuron-specific chromatin remodelling complex. This complex is involved in the regulation of stem/progenitor cells exiting the cell cycle and differentiating into postmitotic neurons. Recent research has indicated that alterations in the cell cycle contribute to the underlying pathogenesis of syndromes associated with ARID1B haploinsufficiency in fibroblasts derived from affected individuals. This review describes studies linking ARID1B to neurodevelopmental disorders and it summarizes the function of ARID1B to provide insights into the pathogenic mechanisms underlying ARID1B-mediated disorders. In conclusion, ARID1B is likely to play a key role in neurodevelopment and reduced levels of wild-type protein compromise normal brain development. Additional studies are required to determine the mechanisms by which impaired neural development contributes to the intellectual disability and speech impairment that are consistently observed in individuals with ARID1B haploinsufficiency.
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- 2015
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9. Mutations in RAB39B cause X-linked intellectual disability and early-onset Parkinson disease with α-synuclein pathology.
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Wilson GR, Sim JC, McLean C, Giannandrea M, Galea CA, Riseley JR, Stephenson SE, Fitzpatrick E, Haas SA, Pope K, Hogan KJ, Gregg RG, Bromhead CJ, Wargowski DS, Lawrence CH, James PA, Churchyard A, Gao Y, Phelan DG, Gillies G, Salce N, Stanford L, Marsh AP, Mignogna ML, Hayflick SJ, Leventer RJ, Delatycki MB, Mellick GD, Kalscheuer VM, D'Adamo P, Bahlo M, Amor DJ, and Lockhart PJ
- Subjects
- Amino Acid Substitution, Australia, Base Sequence, Dopamine metabolism, Female, Gene Expression Regulation, Humans, Intellectual Disability physiopathology, Lewy Bodies metabolism, Male, Middle Aged, Models, Molecular, Molecular Sequence Data, Mutation, Missense, Nerve Degeneration physiopathology, Parkinson Disease physiopathology, Pedigree, Sequence Analysis, DNA, Sequence Deletion, Substantia Nigra physiopathology, rab GTP-Binding Proteins metabolism, Genes, X-Linked, Intellectual Disability genetics, Nerve Degeneration genetics, Parkinson Disease genetics, alpha-Synuclein metabolism, rab GTP-Binding Proteins genetics
- Abstract
Advances in understanding the etiology of Parkinson disease have been driven by the identification of causative mutations in families. Genetic analysis of an Australian family with three males displaying clinical features of early-onset parkinsonism and intellectual disability identified a ∼45 kb deletion resulting in the complete loss of RAB39B. We subsequently identified a missense mutation (c.503C>A [p.Thr168Lys]) in RAB39B in an unrelated Wisconsin kindred affected by a similar clinical phenotype. In silico and in vitro studies demonstrated that the mutation destabilized the protein, consistent with loss of function. In vitro small-hairpin-RNA-mediated knockdown of Rab39b resulted in a reduction in the density of α-synuclein immunoreactive puncta in dendritic processes of cultured neurons. In addition, in multiple cell models, we demonstrated that knockdown of Rab39b was associated with reduced steady-state levels of α-synuclein. Post mortem studies demonstrated that loss of RAB39B resulted in pathologically confirmed Parkinson disease. There was extensive dopaminergic neuron loss in the substantia nigra and widespread classic Lewy body pathology. Additional pathological features included cortical Lewy bodies, brain iron accumulation, tau immunoreactivity, and axonal spheroids. Overall, we have shown that loss-of-function mutations in RAB39B cause intellectual disability and pathologically confirmed early-onset Parkinson disease. The loss of RAB39B results in dysregulation of α-synuclein homeostasis and a spectrum of neuropathological features that implicate RAB39B in the pathogenesis of Parkinson disease and potentially other neurodegenerative disorders., (Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
- Published
- 2014
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10. Mutations in SPRTN cause early onset hepatocellular carcinoma, genomic instability and progeroid features.
- Author
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Lessel D, Vaz B, Halder S, Lockhart PJ, Marinovic-Terzic I, Lopez-Mosqueda J, Philipp M, Sim JC, Smith KR, Oehler J, Cabrera E, Freire R, Pope K, Nahid A, Norris F, Leventer RJ, Delatycki MB, Barbi G, von Ameln S, Högel J, Degoricija M, Fertig R, Burkhalter MD, Hofmann K, Thiele H, Altmüller J, Nürnberg G, Nürnberg P, Bahlo M, Martin GM, Aalfs CM, Oshima J, Terzic J, Amor DJ, Dikic I, Ramadan K, and Kubisch C
- Subjects
- Age of Onset, Animals, Base Sequence, Chromosome Mapping, Cloning, Molecular, DNA Primers genetics, DNA Replication genetics, Flow Cytometry, Fluorescent Antibody Technique, Genes, cdc genetics, Germ-Line Mutation genetics, Humans, Male, Molecular Sequence Data, Pedigree, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Zebrafish genetics, Carcinoma, Hepatocellular genetics, DNA-Binding Proteins genetics, Genomic Instability genetics, Liver Neoplasms genetics, Progeria genetics
- Abstract
Age-related degenerative and malignant diseases represent major challenges for health care systems. Elucidation of the molecular mechanisms underlying carcinogenesis and age-associated pathologies is thus of growing biomedical relevance. We identified biallelic germline mutations in SPRTN (also called C1orf124 or DVC1) in three patients from two unrelated families. All three patients are affected by a new segmental progeroid syndrome characterized by genomic instability and susceptibility toward early onset hepatocellular carcinoma. SPRTN was recently proposed to have a function in translesional DNA synthesis and the prevention of mutagenesis. Our in vivo and in vitro characterization of identified mutations has uncovered an essential role for SPRTN in the prevention of DNA replication stress during general DNA replication and in replication-related G2/M-checkpoint regulation. In addition to demonstrating the pathogenicity of identified SPRTN mutations, our findings provide a molecular explanation of how SPRTN dysfunction causes accelerated aging and susceptibility toward carcinoma.
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- 2014
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11. Expanding the phenotypic spectrum of ARID1B-mediated disorders and identification of altered cell-cycle dynamics due to ARID1B haploinsufficiency.
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Sim JC, White SM, Fitzpatrick E, Wilson GR, Gillies G, Pope K, Mountford HS, Torring PM, McKee S, Vulto-van Silfhout AT, Jhangiani SN, Muzny DM, Leventer RJ, Delatycki MB, Amor DJ, and Lockhart PJ
- Subjects
- Chromatin Assembly and Disassembly, Female, Humans, Male, Abnormalities, Multiple genetics, Cell Cycle genetics, DNA-Binding Proteins genetics, Face abnormalities, Hand Deformities, Congenital genetics, Haploinsufficiency genetics, Intellectual Disability genetics, Micrognathism genetics, Neck abnormalities, Transcription Factors genetics
- Abstract
Background: Mutations in genes encoding components of the Brahma-associated factor (BAF) chromatin remodeling complex have recently been shown to contribute to multiple syndromes characterised by developmental delay and intellectual disability. ARID1B mutations have been identified as the predominant cause of Coffin-Siris syndrome and have also been shown to be a frequent cause of nonsyndromic intellectual disability. Here, we investigate the molecular basis of a patient with an overlapping but distinctive phenotype of intellectual disability, plantar fat pads and facial dysmorphism., Methods/results: High density microarray analysis of the patient demonstrated a heterozygous deletion at 6q25.3, which resulted in the loss of four genes including AT Rich Interactive Domain 1B (ARID1B). Subsequent quantitative real-time PCR analysis revealed ARID1B haploinsufficiency in the patient. Analysis of both patient-derived and ARID1B knockdown fibroblasts after serum starvation demonstrated delayed cell cycle re-entry associated with reduced cell number in the S1 phase. Based on the patient's distinctive phenotype, we ascertained four additional patients and identified heterozygous de novo ARID1B frameshift or nonsense mutations in all of them., Conclusions: This study broadens the spectrum of ARID1B associated phenotypes by describing a distinctive phenotype including plantar fat pads but lacking the hypertrichosis or fifth nail hypoplasia associated with Coffin-Siris syndrome. We present the first direct evidence in patient-derived cells that alterations in cell cycle contribute to the underlying pathogenesis of syndromes associated with ARID1B haploinsufficiency.
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- 2014
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12. Expression of the epithelial Na(+) channel and other components of an aldosterone response pathway in human adrenocortical cells.
- Author
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Burton TJ, Cope G, Wang J, Sim JC, Azizan EA, O'Shaughnessy KM, and Brown MJ
- Subjects
- Animals, Biological Transport, Blotting, Western, Cell Line, Humans, Reverse Transcriptase Polymerase Chain Reaction, Sodium metabolism, Adrenal Cortex cytology, Adrenal Cortex metabolism, Aldosterone metabolism, Epithelial Sodium Channels genetics, Epithelial Sodium Channels metabolism, Gene Expression Regulation, Signal Transduction
- Abstract
We have unexpectedly found expression of the epithelial Na(+) channel (ENaC) in human adrenocortical cells and tested the hypothesis that these cells contain the components of an aldosterone response pathway. Tissue was obtained from patients undergoing adrenalectomy and mRNA and protein expression of recognised components of an aldosterone-response pathway were determined by RT-PCR and Western blotting. The effects of mineralocorticoid receptor agonists and antagonists, amiloride analogues, and extracellular Na(+) on basal and stimulated aldosterone release from immortalised (H295R) cells were determined by radioimmunoassay. Expression of mRNA for alpha-, beta- and gamma-subunits of ENaC, the mineralocorticoid receptor, Nedd4L, Sgk1 and 11beta hydroxysteroid dehydrogenase type II was confirmed in human adrenal cortex. Using Western blotting alpha-, beta- and gamma-ENaC expression was demonstrated in adrenocortical cells. Measurements of 24 h aldosterone release from H295R cells showed stimulation by K(+) and angiotensin II, suppression by both Na(+) and high-concentration 5-(N-ethyl-N-isopropyl) amiloride (EIPA, blocker of Na(+)-H(+) exchange) and no change with benzamil (ENaC blocker). (22)Na-uptake into H295R cells was inhibited by EIPA, but not by benzamil. Our experiments suggest that the components of an aldosterone response pathway are present in human adrenal cortex. Studies in H295R cells, however, suggest that ENaC is not an important mediator of (22)Na-uptake or aldosterone production. Further studies are required to determine the importance of an adrenal aldosterone response pathway.
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- 2009
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13. Effects of alpha-tocopherol on cadmium-induced toxicity in rat testis and spermatogenesis.
- Author
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Yang HS, Han DK, Kim JR, and Sim JC
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- Animals, Antioxidants pharmacology, Cadmium metabolism, Dose-Response Relationship, Drug, Flow Cytometry, Inflammation, Male, Rats, Rats, Sprague-Dawley, Testis pathology, Cadmium pharmacology, Cadmium Poisoning pathology, Spermatogenesis drug effects, Testis drug effects, alpha-Tocopherol pharmacology
- Abstract
Cadmium is known to exert toxic effects on multiple organs, including the testes. To determine if alpha-tocopherol, an antioxidant, could protect testicular tissues and spermatogenesis from the toxic effects of cadmium, six-week old male Sprague-Dawley rats were randomized to receive cadmium at doses of 0 (control), 1, 2, 4 or 8 mg/kg by the intraperitoneal route (Group A) or alpha-tocopherol for 5 days before being challenged with cadmium (Group B) in an identical dose-dependent manner. When both groups received cadmium at 1 mg/kg, there were no changes in testicular histology relative to controls. When Group A received cadmium at 2 mg/kg, undifferentiated spermatids and dead Sertoli cells increased in the seminiferous tubules while interstitial cells decreased and inflammatory cells increased in the interstitial tissues. On flow cytometric analysis, the numbers of elongated spermatids (M1) and round spermatids (M2) decreased while 2c stage cells (M3, diploid) increased. In contrast, when Group B received cadmium at 2 mg/kg, the histological insults were reduced and the distribution of the germ cell population remained comparable to controls. However, alpha-tocopherol had no protective effects with higher cadmium doses of 4 and 8 mg/kg. These findings indicate that alpha-tocopherol treatment can protect testicular tissue and preserve spermatogenesis from the detrimental effects of cadmium but its effectiveness is dependent on the dose of cadmium exposed.
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- 2006
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14. Destruction of the medial forebrain bundle caudal to the site of stimulation reduces rewarding efficacy but destruction rostrally does not.
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Gallistel CR, Leon M, Lim BT, Sim JC, and Waraczynski M
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- Animals, Brain Mapping, Electrodes, Implanted, Male, Nerve Fibers physiology, Neurons physiology, Psychophysics, Rats, Rats, Sprague-Dawley, Hypothalamic Area, Lateral physiology, Medial Forebrain Bundle physiology, Motivation, Self Stimulation physiology, Tegmentum Mesencephali physiology
- Abstract
Rats with an electrode in the medial forebrain bundle (MFB) in or near the ventral tegmental area and another at the level of the rostral hypothalamus sustained large electrolytic lesions at either the rostral or the caudal electrode. The rewarding efficacy of stimulation through the other electrode was determined before and after the lesion. Massive damage to the MFB in the rostral lateral hypothalamus (LH) generally had little effect on the rewarding efficacy of more caudal stimulation, whereas large lesions in the caudal MFB generally reduced the rewarding efficacy of LH stimulation by 35-60%. Similar reductions were produced by knife cuts in the caudal MFB. These results appear to be inconsistent with the hypothesis that the reward fibers consist either of descending or ascending fibers coursing in or near the MFB. It is suggested that the reward fibers are collaterals from neurons with both their somata and their behaviorally significant terminals located primarily in the midbrain.
- Published
- 1996
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15. Scanning electron microscopy of the cat small intestine during Isospora felis infection.
- Author
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Hutchison WM, Pittilo RM, Ball SJ, and Sim JC
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- Animals, Coccidiosis pathology, Intestinal Mucosa ultrastructure, Microscopy, Electron, Scanning, Toxoplasmosis, Animal pathology, Cats parasitology, Coccidiosis veterinary, Intestine, Small ultrastructure
- Published
- 1981
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