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Biomedical subjects

C S Tse

Publications and source records attributed to C S Tse.

At least 19 recordsLinked to original sources

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

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

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

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

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

Isotretinoin in severe, recalcitrant cystic acne: a review.

Isotretinoin, an isomer of retinoic acid, recently has been approved by the Food and Drug Administration for treatment of severe, recalcitrant acne. The most impressive effects include inhibition of sebum production and a reversible decrease in sebaceous gland size. Isotretinoin has proved to be an effective drug; response to therapy has been seen in virtually 100 percent of patients treated. Almost all patients experience reversible cutaneous and mucous-membrane symptoms while on isotretinoin treatment. Other common side effects include conjunctivitis (38 percent) and eye irritation (50 percent). The recommended dosage is 1-2 mg/kg/d for no longer than 16 weeks. Isotretinoin is currently the treatment of choice for severe, recalcitrant acne; however, because of potential side effects associated with retinoids, isotretinoin should be reserved for those patients who are unresponsive to conventional therapy, including topical and systemic antibiotics.

Acne Vulgaris

Baker's asthma (grain-dust-induced asthma).

A 48-year-old black male with no underlying atopy developed asthma after working nine years at a bakery. The attacks of wheezing were preceded by nasal symptoms and usually occurred after several hours of work. Skin testing revealed reactivity to dust, molds, and wheat extracts; serum level of IgE was normal, and a RAST screen to common allergens was negative. A bronchial provocation test using commercial wheat extract was negative, but the same test using the patient's own bakery flour resulted in an immediate positive reaction. The pathogenesis and management of grain-dust-induced asthma are discussed.

Adult

Diverse profiles of immunoreactivity in toluene diisocyanate (TDI) asthma.

Possible immunoreactivity to chemically well-characterized mono- and diisocyanate protein conjugates was reevaluated in 15 workers with TDI asthma and 17 normal (nonexposed) volunteers. Lymphocytes of nine sensitive workers were incubated with TDI human serum albumin (HSA) conjugates. Leucocyte inhibitory factor (LIF) was produced. Leucocyte inhibitory factor was also induced by hexamethylene diisocyanate (HDI) protein conjugates in four of these workers who had no prior history of exposure to HDI. Disappearance of TDI- and HDI-induced LIF was noted in several sensitive workers who were removed from further TDI exposure. Three LIF-positive workers also demonstrated positive intracutaneous reactivity to TDI-HSA. One workers had a markedly positive RAST (25.5% binding) to a monofunctional (p-tolyl isocyanate) protein reagent. These studies suggest that isocyanates have the potential for eliciting heterogeneous immune responses in certain subpopulations of exposed workers. Continued contact with isocyanates may be necessary for maintenance of specific immunity. Possible cross reactivity between TDI and HDI may be determined by new antigenic sites created by isocyanate protein interactions.

Adult

In vivo suppression and enhancement of the murine homocytotropic antibody response by staphylococcal enterotoxin A.

Effects of staphylococcal enterotoxin A (SEA) on the mouse homocytotropic antibody (HCA) system were studied. Groups of BDF mice received 10 micrograms SEA either orally or intraperitoneally at 0, 24, 48 h before or after immunization with 100 micrograms ovalbumin in 1 mg A1(OH)3 gel. Primary and secondary HCA responses were determined by 48-hour passive cutaneous anaphylactic reactions in genetically hairless mice. It was found that effects of SEA on HCA responses were dependent on the time and route of SEA administration. In general, early administration (48 h before immunization) of SEA showed suppression, while later administration (either 24 h before or after immunization) of SEA demonstrated enhancement. A further delay of SEA administration (48 h after immunization) exerted suppressive effects except when it was given intraperitoneally in the anamnestic HCA experiments. The mouse HCA system proved to be a suitable in vivo correlate of in vitro plaque-forming cell responses modulated by SEA.

Animals