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Biomedical subjects

F Chang

Publications and source records attributed to F Chang.

At least 127 records · Page 7Linked to original sources
PubMed1990

Verrucous carcinoma of the anus containing human papillomavirus type 16 DNA detected by in situ hybridisation: a case report.

Verrucous carcinoma of the anus is a distinct and rare variant of well-differentiated squamous cell carcinoma. A case of anal verrucous carcinoma in a 35 year old man was studied by light microscopy and in situ DNA hybridization. Human papillomavirus (HPV) type 16 DNA sequences were demonstrated in the tumour cells, as well as in cells showing koilocytotic and dyskeratotic changes. The possible viral (HPV) aetiology of verrucous carcinoma is considered with a review of the previous literature.

Adult↗
PubMed1990

Acetylcholine reverses effects of beta-agonists on pacemaker current in canine cardiac Purkinje fibers but has no direct action. A difference between primary and secondary pacemakers.

We have investigated the actions of acetylcholine in the absence and presence of the beta-agonist isoproterenol in cardiac Purkinje fibers. beta-Agonists, like isoproterenol, increase the magnitude of the pacemaker current (If) in cardiac myocytes by shifting its activation voltage more positive on the voltage axis. We find that acetylcholine has no effect on If in the absence of isoproterenol. However, if If is first increased by beta-agonist stimulation, acetylcholine can then return If to control levels. This effect on If is exerted through muscarinic receptors since atropine prevents this action of acetylcholine. Functionally, this action of acetylcholine can guarantee the maintenance of ventricular pacemakers when there is high parasympathetic tone but can also prevent extra ventricular beats when sympathetic and parasympathetic tone are both high.

Acetylcholine↗
PubMed1990

Detection of human papillomavirus DNA in cytologic specimens derived from esophageal precancer lesions and cancer.

A series of 80 esophageal cytologic specimens derived from the same number of patients with previously diagnosed squamous cell dysplasia of the esophagus were examined for the presence of human papillomavirus (HPV) infection by filter in situ hybridization (FISH), using a mixed DNA probe containing HPV types 11, 16, and 18. All the patients came from an area at high risk for esophageal cancer in China. A total of 53 cases (66.3%) were demonstrated as HPV-DNA-positive. HPV DNA was detected in 22.2% (2 of 9) of the patients without cytologic atypia, in 50% (3 of 6) with mild dysplasia, in 80.6% (25 of 31) with moderate dysplasia, in 67.9% (19 of 28) with severe dysplasia, and in 66.7% (4 of 6) with an invasive squamous cell carcinoma. The present results confirm the recent findings on HPV involvement in esophageal squamous cell lesions. They support the hypothesis that HPV is a possible etiologic agent in esophageal carcinogenesis, most probably acting synergistically with physical, chemical, and/or nutritional factors that have previously been related with this malignancy in the high-risk areas of China.

Carcinoma, Squamous Cell↗
PubMed1984

Metastatic breast cancer complicating pregnancy. A case report.

An 18-year-old patient at 15 weeks' gestation was hospitalized for a high fever and delirium secondary to a presumed viral syndrome. She had massive hepatomegaly, and a small breast lump was noted incidentally. Abnormalities in the differential blood count and liver function tests were found in addition to thrombocytopenia. Bone marrow biopsy revealed metastatic breast cancer.

Adolescent↗
PubMed1983

Effect of exercise and diet on triglyceride metabolism in rats with moderate insulin deficiency.

The ability of exercise and diet to modify the effects of moderate streptozotocin-induced insulin deficiency on triglyceride metabolism has been studied in the rat. Insulin-deficient rats allowed to run spontaneously in exercise wheel cages had significantly lower (P less than 0.001) plasma glucose levels (187 +/- 19 mg/dl) than either sedentary (374 +/- 24 mg/dl) or sucrose-fed (450 +/- 13 mg/dl) diabetic rats, despite the fact that plasma insulin levels were comparable in all these groups. Plasma triglyceride (TG) levels in exercise-trained rats with diabetes (51 +/- 5 mg/dl) were actually lower than in control rats with normal glucose tolerance (90 +/- 14 mg/dl). In contrast, plasma TG levels were higher than control levels in diabetic sedentary rats (128 +/- 11 mg/dl), and severe hypertriglyceridemia developed in sucrose-fed diabetic rats (369 +/- 35 mg/dl). The ability of exercise training to attenuate diabetic hypertriglyceridemia, which was observed in both chow-fed and sucrose-fed rats, was secondary to a decrease in TG secretion, and appeared to be related to lower plasma FFA concentrations. In contrast, the accentuation of diabetic hypertriglyceridemia seen in sucrose-fed rats was related to a defect in TG catabolism. Adipose tissue lipoprotein lipase (LPL) activities were essentially identical in all diabetic rats, suggesting that the observed difference in TG kinetics could not be attributed to concomitant increases or decreases in adipose tissue LPL activity. These results emphasize the powerful impact of exercise and diet on TG metabolism in rats with moderate degrees of insulin deficiency.

Adipose Tissue↗
PubMed1983

Effect of exercise training and sucrose feeding on insulin-stimulated glucose uptake in rats with streptozotocin-induced insulin-deficient diabetes.

The effect of exercise training and a sucrose-rich diet on insulin-stimulated glucose disposal was studied in rats with streptozotocin-induced insulin deficiency. Rats were injected with streptozotocin (40 mg/kg), and 3 days later divided into three groups with equal degrees of hyperglycemia. One group of rats was allowed to run spontaneously on exercise wheels, another group remained sedentary but ate a sucrose-rich diet (66% sucrose), and the third also remained sedentary but consumed conventional rat chow. Three weeks later, we determined the effect of these various programs on postabsorptive plasma glucose and insulin levels, as well as on the ability of exogenous insulin to stimulate disposal of a glucose load during a period in which endogenous insulin was suppressed by epinephrine and propanolol. Basal plasma insulin levels were the same in all three groups, but plasma glucose levels were significantly lower (P less than 0.001) in exercise-trained rats, and significantly higher (P less than 0.05) in sucrose-fed rats, than in chow-fed diabetic rats. The inference that exercise training markedly enhanced insulin action in rats with insulin deficiency was borne out by direct estimation of insulin-stimulated glucose disposal. In contrast, sucrose-fed diabetic rats seemed to be more insulin-resistant than chow-fed diabetic rats. These results provide direct evidence that spontaneous exercise can dramatically attenuate the severity of diabetes in insulin-deficient rats by enhancing insulin action. DIABETES 32:165-168, February 1983.

Animals↗
PubMed1982

Benign ulceration of the cecum presenting with massive hemorrhage: report of a case and review of the literature.

Massive gastrointestinal hemorrhage secondary to benign cecal ulceration is a rare occurrence. The diagnosis of bleeding from this benign condition is rarely entertained and is often a finding on a pathologic examination. A case of massive hemorrhage from a cecal ulcer is presented, and the literature is reviewed. The role of angiographic demonstration of the lesion, if angiography is readily available, is emphasized, but surgery is the definitive therapy.

Cecal Diseases↗
PubMed1981

Effect of exercise-training on the metabolic manifestations of streptozotocin-induced diabetes in the rat.

Streptozotocin-induced insulin deficiency of a moderate degree was produced in exercise-trained and sedentary young rats, and determinations made of subsequent changes in plasma glucose, triglyceride, and insulin concentrations. Exercise-training attenuated the rise in both plasma glucose and triglyceride concentrations associated with insulin deficiency. Plasma insulin levels were, if anything, lower in exercise-trained rats. Thus, the beneficial effects of exercise-training on plasma glucose and triglyceride concentrations could not be due to the preservation of endogenous insulin secretion, and appear to be secondary to enhanced insulin sensitivity.

Animals↗
PubMed1978

Markedly raised synovial fluid leucocyte counts not associated with infectious arthritis in children.

Synovial fluid leucocyte counts greater than 50 000 cells/mm3 (50 X 10(9)/1) are usually associated with infectious arthritis. Six children, 3 of whom meet the criteria for juvenile rheumatoid arthritis (JRA), are described with synovial fluid white blood cell counts greater than 88 000 cells/mm3 (88 X 10(9)/1). Two had synovial fluid leucocyte counts greater than 100 000 cells/mm3 (100 X 10(9)/1). The diagnosis of infectious arthritis was unlikely in these 6 children since the synovial fluid smears and cultures for infectious agents were negative and their histories atypical for infection. While in most instances such markedly raised synovial fluid leucocyte counts indicate infection, this finding is not diagnostic of septic arthritis.

Adolescent↗
PubMedDate not supplied

Movement of a cytokinesis factor cdc12p to the site of cell division.

A key question in cytokinesis is how the plane of cell division is positioned within the cell. Although a number of cytokinesis factors involved in formation of the actomyosin contractile ring have been identified, little is known about how these factors are localized and assembled at the cell-division site. Cells of the fission yeast Schizosaccharomyces pombe divide using a medial actomyosin ring that assembles in early mitosis [1]. The S. pombe cdc12 gene encodes a formin, a member of a family of proteins that have functions in cytokinesis and cell polarity and that may bind Rho/Cdc42 GTPases, profilin and other actin-associated proteins [1] [2] [3] [4]. The cdc12 protein (cdc12p) is required specifically for medial-ring assembly during cytokinesis and is a component of this ring [2] [5]. In this study, cdc12p was found, during interphase, in a discrete, motile cytoplasmic spot that moved to the future site of cell division at the onset of mitosis. Three lines of evidence indicated that this cdc12p spot moved on both actin and microtubule networks: movement required either actin or microtubules; the spot was associated with actin and microtubule structures; and individual spots were seen to move along both microtubule and non-microtubule tracks. These findings demonstrate that a cytokinesis factor may travel on both microtubule and actin networks to the future site of cell division.

Actins↗