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Biomedical subjects

C S Tse

Publications and source records attributed to C S Tse.

13 recordsLinked to original sources
PubMed1992

Inhibition of human endothelial cell proliferation in vitro in response to n-butyrate and propionate.

The study aimed to investigate the effects of n-butyrate and propionate on the proliferation and viability of human endothelial cells in culture. Proliferation was assessed by a 24-hour bromodeoxyuridine pulse labelling and immunoperoxidase method and viability was assessed by a colorimetric viability (MTT) assay. Endothelial cells were isolated from human umbilical vein by collagenase digestion. Experiments were performed on 96-well plates and cultures were exposed to different concentrations of n-butyrate and propionate for 2 days. n-butyrate and propionate caused significant reductions in the proliferation of endothelial cells at concentrations of 1.25 mM and 10 mM respectively (p less than 0.05); the reduction in proliferation was dose-dependent for both agents. n-butyrate was a more potent inhibitor of proliferation than propionate. However, there were no significant effects on the viability of the cells with both agents up to the highest concentrations tested (25 mM). The data indicate that n-butyrate and propionate inhibit endothelial cell proliferation which may contribute to the pathogenic effects of dental plaque in periodontal disease.

Analysis of Variance↗
PubMed1988

An adverse drug reaction reporting program in a community hospital.

An adverse drug reaction (ADR) surveillance program implemented in a 472-bed acute care community hospital consists of three components: specific indicators that nurses and pharmacists can use to evaluate reactions for reporting, an ADR reporting form and procedure, and innovative computerized screening for ADRs. In the program's first year, ADR reporting has increased 13-fold, and an important ADR to an antibiotic has been detected and publicized, resulting in modified prescribing patterns. Careful planning and frequent, intensive in-service training are key to the program's success.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1986

Anorexia after adrenalectomy in gold thioglucose-treated obese mice: role of adipose tissue mass.

We have previously shown that following adrenalectomy, gold thioglucose (GTG)-treated hyperphagic obese mice exhibit anorexia, weight loss and a pronounced hypoglycemia which leads ultimately to their death. In the present study, we sought to determine whether the increased adipose tissue mass which is characteristic of GTG-treated obese mice exerted a role in the onset and development of anorexia after adrenalectomy. Accordingly, the effects of adrenalectomy on food intake, weight gain, plasma glucose and corticosterone levels were investigated in normal untreated controls, GTG-treated hyperphagic obese mice and GTG-treated non obese mice. The GTG-treated non obese mice were prepared by restricting their daily intake of chow (pair-feeding) to that consumed by normal untreated mice. After adrenalectomy, all mice were allowed free access to food. As expected, all GTG-treated hyperphagic obese mice exhibited anorexia and weight loss following adrenalectomy. In contrast, about half (52%) of the GTG-treated non obese mice exhibited anorexia and weight loss after adrenalectomy. The response of the GTG-treated non obese adrenalectomized mice was not due to differences in adrenal insufficiency since all adrenalectomized mice had blood levels of corticosterone of less than 0.5 microgram%. These findings indicate that whereas the increased adipose tissue mass of the GTG-treated obese mice appears to be associated with an increased incidence of anorexia following adrenalectomy, increased adipose tissue mass alone does not appear to be essential for the occurrence of anorexia.

Adipose Tissue↗
PubMed1986

Adrenalectomy induced anorexia in gold thioglucose-treated obese mice: metabolic and hormonal changes.

Adrenalectomy of gold thioglucose (GTG)-treated hyperphagic obese mice had been shown by us earlier to result in anorexia, weight loss, hypoglycemia and subsequent death of all mice. More recent studies suggest that adipose tissue mass may not be the critical determinant of anorexia since a large proportion of GTG-treated non obese (pair-fed to curb obesity) mice when challenged with adrenalectomy also developed anorexia. The aim of the present studies was to determine whether the changes in circulating metabolites, namely, glucose, free fatty acids and hormones, including insulin, glucagon and ACTH, which accompany adrenalectomy, might provide a clue to the causative agent for the onset of anorexia in GTG obese and non obese mice. Accordingly, plasma levels of glucose, free fatty acids, insulin, glucagon and ACTH were measured in GTG-treated obese, non obese and in normal untreated mice following adrenalectomy or a sham operation. Preoperatively, plasma insulin levels were significantly elevated in GTG obese mice whereas plasma glucose, free fatty acids and glucagon levels were not appreciably different than those of untreated controls. Upon adrenalectomy and onset of anorexia, GTG obese mice exhibited a progressive decline in blood glucose and insulin levels; plasma free fatty acids increased precipitously but only after the first day. Plasma glucagon levels declined immediately following adrenalectomy, however, by the 6th day postoperatively they were significantly elevated above the sham operated obese and untreated controls. Prior to adrenalectomy, the pair-fed GTG non obese mice exhibited blood glucose and insulin levels well below the levels of untreated controls and GTG obese mice whereas plasma free fatty acids and glucagon levels were markedly elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1986

Central nervous system control of hyperphagia in hypothalamic obesity: dependence on adrenal glucocorticoids.

Gold thioglucose (GTG)-treated hyperphagic obese mice exhibit a pronounced anorexia upon adrenalectomy which is reversed by the systemic administration of adrenal glucocorticoids. To determine whether the return of hyperphagia was mediated by an action of the hormones on the central nervous system, food intake and body weight were monitored in anorexic GTG-treated obese adrenalectomized mice which received a single intracerebroventricular (icv) injection of very small amounts of adrenal glucocorticoids, including cortisone, corticosterone, and dexamethasone. The responses of untreated controls and adrenalectomized control mice were also studied. To rule out possible systemic effects of icv injections of adrenal glucocorticoids, food intake and body weight were also monitored in similar mice given a single ip injection of the hormones. We found that hyperphagia was restored and weight loss abolished in anorexic GTG-treated obese adrenalectomized mice after a single icv injection of adrenal glucocorticoids; the dose of cortisone required was found to be 1/60th of that previously shown to be needed systemically to restore hyperphagia. A single ip injection of these adrenal hormones in the small amounts given icv failed to induce hyperphagia in these mice. The icv and ip injections of the adrenal glucocorticoids did not significantly affect food intake or body weight of untreated controls and adrenalectomized control mice. These findings indicate that adrenal glucocorticoids act via the central nervous system in restoring hyperphagia in anorexic GTG-treated obese adrenalectomized mice.

Adrenal Glands↗
PubMedDate not supplied

Is home tooth bleaching gel cytotoxic?

Tooth whitening systems are widely used clinically and for home usage. The aim of this study was to determine the effects of two bleaching gels, each containing 10 percent and 15 percent carbamide peroxide, respectively, a 'bleaching gel' without carbamide peroxide, and carbamide peroxide alone on the viability of human endothelial cells in vitro in comparison with culture medium that acted as a negative control. The incubation period used was 30 minutes. A colorimetric viability assay (MTT assay) was employed. The results showed that the gel without carbamide peroxide is not cytotoxic compared to the negative control, while carbamide peroxide on its own and 10 percent and 15 percent carbamide peroxide bleaching gels were cytotoxic, but there were no significant differences (p greater than 0.05) among these latter three test groups. These data indicate that 10 percent and 15 percent carbamide peroxide bleaching gels are cytotoxic and that carbamide peroxide is the component responsible for this cytotoxic effect. This paper also discusses why this in vitro cytotoxic effect appears not to be significant in vivo.

Analysis of Variance↗