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1.
The cellular and regional distribution of glutathione (GSH) and GSH-related enzyme systems involved in cellular defense against reactive oxygen species and electrophilic xenobiotics in the nervous system has been extensively studied. However, little is known about the subcellular distribution of GSH systems in brain tissue and cultured neural cells. The present study investigates the distribution of mitochondrial and cytosolic GSH and GSH-related enzymes in cultured cerebellar astrocytes and granule cells, and compares them with levels in the adult rat cerebellum. Cytosolic GSH levels and cytosolic activities of glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in astrocytes were 57, 153, 245, and 92% higher than those found in granule cells, respectively. In contrast, granule cells contained significantly higher mitochondrial GSH levels than astrocytes. Granule cells also demonstrated comparable mitochondria/cytosolic concentrations of GSH and GR, GPX and GST activities to those observed in the cerebellar tissue, whereas ratios in astrocytes were markedly lower. Although in vitro treatments with 100 μM ethacrynic acid depleted both cytosolic and mitochondrial GSH in cultured astrocytes and granule cells in a time-dependent fashion, cellular GSH in granule cells was more resistant to the GSH-depleting agent than astrocytes. These results suggest that although GSH and GSH-related enzymes are abundant in cytosolic compartments of astrocytes, mitochondrial pools are relatively small. Since brain mitochondria are sites of significant hydrogen peroxide generation, the mitochondrial localization of GSH and its associated enzymes in neural cells provide important defenses against toxic oxygen species in the nervous system. Differences in subcellular distribution of GSH systems in individual neural cell types may provide a basis for selective cellular and/or subcellular expression of neurotoxicity. 相似文献
2.
D Choudat F Neukirch P Brochard G Barrat J Marsac F Conso M Philbert 《Occupational and environmental medicine》1988,45(6):376-380
Respiratory manifestations have been reported after exposure to hydroquinone and to methionine. One hundred and three men in the same chemical plant were divided into three groups according to their exposure and compared by questionnaire, respiratory functional tests with methacholine then salbutamol challenges, and measurements of serum immunoglobulins G and E. Group H included 33 workers exposed to hydroquinone, trimethyl-hydroquinone, and retinene-hydroquinone. Group M included 15 workers exposed to methionine. Group C was a control group of 55 workers. The prevalence of respiratory symptoms was higher in the two exposed groups. Before challenges, pulmonary function values were significantly lower in groups H and M than those in group C. The challenges induced significant variations in the three groups but these variations were less pronounced in group M than in the other groups. The level of immunoglobulin G in group H (m +/- SD = 12.5 gram/liter +/- 2.6) was significantly higher than in group C (10.6 gram/liter +/- 2.4; p less than 0.002). The level of immunoglobulin E in group H (m = 140 IU/l) was also higher in group C (109 IU/l) but this difference was not significant. These findings suggest that exposure to methionine and to hydroquinone and its derivatives induce ventilatory impairment, perhaps by an immunological mechanism. 相似文献
3.
Ghrelin expression in hyperplastic and neoplastic proliferations of the enterochromaffin-like (ECL) cells 总被引:1,自引:0,他引:1
Ghrelin, a recently discovered peptide isolated from the gastric corpus mucosa, is believed to be important in the regulation
of growth hormone secretion and has been shown to increase appetite and food intake as well. It may also have other gastrointestinal
and cardiac functions. Because a cell of origin for ghrelin has not been convincingly identified in the gastric mucosa thus
far, we studied the immunohistochemical expression of ghrelin in proliferative lesions of the enterochromaffin-like (ECL)
cells—a cell that is not only exclusively confined to the gastric corpus mucosa but is its dominant endocrine cell type as
well.
Formalin-fixed, paraffin embedded tissues from three cases of gastric ECL cell hyperplasia and five ECL carcinoids (three
with coexisting foci of diffuse, linear, and micronodular hyperplasia) were immunohistochemically stained for ghrelin, using
a commercially available antibody. The Sevier-Munger stain for ECL cells and immunohistochemical stains for chromogranin,
gastrin, serotonin, somatostatin, and vesicular monoamine transporter-2 (VMAT-2) were performed on parallel sections for correlation
with the ghrelin staining results.
All ECL cell carcinoids and hyperplastic lesions were positive for both the Sevier-Munger and the immunohistochemical stains
for chromogranin and VMAT-2. Immunoreactivity for ghrelin was seen in 4/5 ECL carcinoids, all cases of ECL cell hyperplasia,
as well as in all areas with linear and micronodular hyperplasia adjacent to the ECL cell carcinoids. In each instance, such
staining was confined to the Sevier-Munger, and VMAT-2 positive cells only.
Our findings indicate that the ECL cells are either the ghrelin-producing cells of the gastric mucosa or acquire the capability
to synthesize ghrelin during proliferative states encompassing the entire hyperplasia to neoplasia spectrum. In view of the
orexigenic and other known actions of ghrelin, the functional and/or biologic significance of ghrelin production in such ECL
cell proliferations needs to be investigated further. 相似文献
4.
5.
Characterization of xenobiotic-metabolizing enzymes and nitrosamine metabolism in the human esophagus 总被引:5,自引:2,他引:5
Smith TJ; Liao A; Wang LD; Yang GY; Starcic S; Philbert MA; Yang CS 《Carcinogenesis》1998,19(4):667-672
Esophageal cancer has been associated with tobacco smoking, and
nitrosamines are possible causative agents for this cancer. The present
study investigated the metabolism of the tobacco carcinogens N'-
nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1- butanone
(NNK), and N-nitrosodimethylamine (NDMA), as well as the presence of
xenobiotic-metabolizing enzymes in human esophageal tissues from
individuals in the United States and Huixian, Henan Province, China (a
high-risk area for esophageal cancer). All esophageal microsomal samples
activated NNN and the metabolic rate was 2-fold higher in the esophageal
samples from China than the USA. All microsomal samples activated NDMA.
However, most of the microsomal samples did not activate NNK.
Troleandomycin (an inhibitor of cytochrome P450 3A) decreased the formation
of NNN-derived keto acid by 20-26% in the esophageal microsomes. The
activities for NADPH: cytochrome c reductase, ethoxycoumarin O-deethylase,
NAD(P)H: quinone oxidoreductase and glutathione S-transferase were present
in the esophageal samples. Coumarin 7-hydroxylase (a representative
activity for P450 2A6) activity was not detected in the esophageal
microsomal samples. The activities for nitrosamine metabolism and
xenobiotic- metabolizing enzymes were decreased (by 30-50%) in the squamous
cell carcinomas compared with their corresponding non-cancerous mucosa. The
presence of activation and detoxification enzymes in the esophagus may play
an important role in determining the susceptibility of the esophagus to the
carcinogenic effect of nitrosamines. Our results suggest that P450s 3A4 and
2E1 are involved in the activation of NNN and NDMA, respectively, in the
human esophagus.
相似文献
6.
Kamila Pires de Carvalho Mariana Tavares Miranda Lima Fernanda Silva Mazzutti Isis Danyelle Dias Custódio Paula Philbert Lajolo Canto Carlos Eduardo Paiva Yara Cristina de Paiva Maia 《Clinical breast cancer》2019,19(1):e208-e219
Purpose
To study the use of functional capacity (FC) level and duration of aromatase inhibitor (AI) therapy with adiposity parameters in women with breast cancer.Patients and Methods
FC was evaluated through the Health Assessment Questionnaire, which was assessed by classification and divided into 3 groups: G1 = mild to moderate difficulty, G2 = moderate to severe disability, and G3 = severe or very severe disability. Body mass, height, and waist circumference (WC) were measured, and body mass index (BMI) was calculated. Bioelectrical impedance analysis was used to calculate body fat (BF) and fat-free mass. The women were divided into 2 time groups (T1 and T2), which were determined by the median months of AI use (T1 ≤ 29.5 and T2 > 29.5 months).Results
Impaired FC and adiposity parameters were significantly positively correlated. In addition, physical exercise was significantly lower in women assessed as G2 and G3 compared to those assessed as G1. The effect of FC on BMI, BF, and WC was also verified, as was the effect of the duration of AI receipt on BMI and BF. Women at T1 had significantly greater functional disability, BMI, and BF values. In addition, although not statistically significant, women in T1 who were assessed as G3 presented higher BMI, WC, and BF values than those in T2.Conclusion
Adiposity above the recommended parameters and impaired FC were associated with the shortest time of receipt of adjuvant endocrine therapy with AI. 相似文献7.
8.
Sahana K.S. Prakash R.M. Saldanha Supriya Kushwah Anitha S. Prabhu 《The Indian journal of tuberculosis》2018,65(3):195-199
Introduction
In spite of having BCG vaccination and tuberculosis control program for the last 50 years, prevalence of tuberculosis continues to be high in India. Inadequate diagnostic methods, suboptimal treatment and monitoring, and the lack of vigilant reporting system are some of the contributing factors for the failure of TB control.Objectives
To know the current practices among local pediatricians regarding management of TB.Materials and methods
Field based cross sectional study. All the registered pediatricians who were practicing in Mangalore, (list – local IAP branch) were included in the study. A structured Questionnaire on signs and symptoms of TB, diagnosis, strategies adopted in treatment, MDR tuberculosis and reporting of cases to RNTCP was asked. Management practice standards according to the Updated National Guidelines for Pediatric Tuberculosis in India, 2012, RNTCP guidelines in consensus with IAP, latest at the time of the study.Results
50 pediatricians participated in the study with 62% having an attachment to the teaching institution. More than 50% identified all the symptoms of TB. 64% were sending chest X-ray, Mantoux test and gastric lavage/induced sputum examination for AFB to diagnose TB. 22% were not stressing for AFB examination. Still 16% told serological tests as one of the diagnostic modality. 52% were not aware about the diagnosis of latent TB. In 16% of their cases ATT was on a trial basis. Only 52% of the clinicians are adhering to updated national (RNTCP) guidelines. 30% felt still there are drawbacks in the current RNTCP guidelines. 72% knew the correct definition of MDR tuberculosis. But only 36% of them knew the diagnostic method (gene expert/CB NAAT) of confirming the MDR TB.Conclusion
Management practices are found to be still suboptimum. Better engagement of the private sector is urgently required to improve TB management practices and to prevent diagnostic delay and drug resistance. 相似文献9.
10.
Jasmine Aliya G.V. Akila Durai Vanitha M. Anitha Rani Shriraam Vanishree V. Samya T. Gayathri Mahadevan Shriraam 《International journal of diabetes in developing countries.》2021,41(2):293-300
International Journal of Diabetes in Developing Countries - There is a huge burden of diabetes-related complications, both microvascular and macrovascular, in India. With the rising prevalence of... 相似文献