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Biomedical subjects

J L Chang

Publications and source records attributed to J L Chang.

66 records · Page 4Linked to original sources
PubMed1977

Estrogen-induced gonadotropin surges in decerebrated female rhesus monkeys with medial basal hypothalamic peninsulae.

Hypothalamic peninsulae, posteriorly continuous with the brain stem, were produced in ovariectomized rhesus monkeys by aspiration of the cerebral hemispheres and all brain structures anterior and dorsal to the optic chiasm. These preparations were sustained for 52 to 60 h postoperatively by maintaining blood gases and pH within physiological limits and by supporting arterial blood pressure, when necessary, with infusions of rhesus monkey blood and norepinephrine. The sc injection of estradiol benzoate (EB) to such animals upon completion of the ablation procedure was followed 18-24 h later by unambiguous surges of serum LH and FSH with durations in the excess of 24 h. These findings are consonant with the view that the central components of the control system that initiates the preovulatory gonadotropin surge in the rhesus monkey are resident within the medial basal hypothalamic-hypophysial apparatus.

Animals↗
PubMedDate not supplied

The expression of HPV-16 E5 protein in squamous neoplastic changes in the uterine cervix.

To investigate the expression of human papillomavirus type 16 (HPV-16) E5 protein in squamous neoplastic changes in the uterine cervix, the specific E5 antibody was generated and used to identify the expression of E5 protein in 40 cases of HPV-16-positive tissues and 5 previously identified HPV-negative normal cervical tissues. The results revealed that E5 protein was primarily expressed in the lower third of the epithelium in low-grade squamous intraepithelial lesions (SILs) and throughout the whole epithelium in high-grade SILs. In invasive squamous carcinoma, 60% of HPV-16-infected cancers which contained the episomal viral genome had the E5 gene, and could express E5 protein which was located throughout the whole epithelium. Previously, we documented the expression of type I growth factor receptors [ERBB1/EGFR (epidermal growth factor receptor), ERBB2, ERBB3 and ERBB4] in the full range of cervical neoplasias by immunohistochemistry assay. Hence, in this study, we extensively analyzed the correlation between the expression of E5 protein and the expression of type I growth factor receptors. Among 40 HPV-16- infected cervical neoplasias, we found that the expression of E5 protein was significantly correlated with either the expression of the ERBB1 or the ERBB4 receptor.

Animals↗
PubMedDate not supplied

Effect of exercise on cation transport in human red cells.

To test the hypothesis that environmental as well as genetic factors are important determinants of monovalent cation transport systems in humans, and to explore potential basic mechanisms of the alleged antihypertensive effects of habitual exercise, we studied the effects of a 12-week exercise program (45 minutes, 3-5 times per week) upon several membrane transport parameters in erythrocytes from a population of 63 adult men (30 normotensive subjects and 33 essential hypertensive patients). Subjects were randomly assigned into either an exercise group or a sedentary control group, and clinical and membrane transport parameters were measured at baseline and after 3 months. Exercising subjects demonstrated increases in maximal treadmill work capacity (p less than 0.001) and high-density lipoprotein cholesterol levels (p = 0.009) as well as decreases in heart rate at a fixed submaximal workload (p less than 0.05) and body weight (p less than 0.001) relative to the sedentary group. In conjunction with these well-described effects of exercise conditioning, the exercise group demonstrated a significant decrease in Na+-Li+ countertransport (p = 0.002), without significant changes in any other transport parameters measured. Blood pressure was not significantly altered in either group. We conclude that powerful environmental influences such as exercise training may act in concert with genetic factors to influence monovalent cation transport in humans and must be considered in further investigations of the pathophysiological linkage between altered monovalent cation transport and essential hypertension.

Adult↗
PubMedDate not supplied

Enflurane-induced grand mal seizures during otic microsurgery.

Abnormal electroencephalographic seizure-like activity and myoclonic movements have been recognized during enflurane anesthesia. This is most commonly seen in the presence of respiratory alkalosis and high concentrations of enflurane. Immediate and delayed postoperative generalized tonic-clonic convulsions have also been reported after enflurane anesthesia. Experimental studies have shown that auditory stimuli could facilitate seizure activity during deep enflurane anesthesia. Here we report a case of intraoperative generalized tonic-clonic convulsion during low concentrations of enflurane without evidence of hyperventilation and the presence of auditory stimulation.

Adult↗
PubMedDate not supplied

Case report: increased myocardial irritability with halothane and aminophylline.

Increased cardiac sensitivity to epinephrine during halothane anesthesia has been well documented; however, there are few reports of increased cardiac irritability due to interaction between halothane anesthesia and aminophylline. The following case report is suggestive of such an interaction resulting in ventricular tachycardia.

Aminophylline↗