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Biomedical subjects

E Hall

Publications and source records attributed to E Hall.

135 records · Page 8Linked to original sources
PubMedDate not supplied

Identification of 3H-bradykinin binding sites in PC-12 cells and brain.

3H-Bradykinin binding sites with the characteristics of receptors were identified in homogenates of bovine hippocampus and PC-12 cells. The characteristics of the binding were similar in both types of tissue and paralleled those of the B2 bradykinin receptor. Following exposure to nerve growth factor for 72 hours, the number of BK binding sites in PC-12 cells significantly increased, but other characteristics of the binding remained unchanged.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Effects of bradykinin on PC-12 cell differentiation.

PC-12 cells are used as a model for neuronal differentiation because they assume a neuronal phenotype, including the extension of neurites, when exposed to nerve growth factor (NGF). The present results show that bradykinin (BK) also causes PC-12 cells to extend neurites. In addition, BK potentiates the neurite-extending effect of nerve growth factor (NGF), an action which is attenuated by a BK antagonist. The potentiation of neurite extension produced by the combination of BK and NGF may be mediated at the receptor level, as indicated by an NGF-induced alteration of BK binding.

Animals↗
PubMedDate not supplied

In vitro metal inhibition of N-methyl-D-aspartate specific glutamate receptor binding in neonatal and adult rat brain.

The in vitro effect of methyl mercury (MM) and lead (Pb) on N-methyl-D-aspartate (NMDA)-specific glutamate receptor binding in neonatal (10 days old) and adult rat brain was investigated. The cerebral cortex was isolated from the neonatal and adult male Sprague-Dawley rats and the synaptic plasma membranes were prepared to study the NMDA-specific glutamate receptor binding by using (3H)-glutamic acid. The metal salts such as methyl mercury chloride and lead acetate were used to study the effect of MM and Pb. Both MM and Pb significantly inhibited the receptor binding in neonatal and adult rat brain in a concentration-dependent manner. MM (IC50:0.95 +/- 0.08 microM) was more potent in inhibiting the receptor binding than Pb (IC50:60 +/- 7 microM) in neonatal rat brain. A similar high potency was observed for MM than Pb in adult rat brain but the IC50 values are very high (70 +/- 6 microM and 300 +/- 24 microM respectively) indicating less effect compared to neonatal brain. The data suggest that NMDA-receptor binding was more sensitive to MM and Pb in neonatal brain than in adult. MM was more effective than Pb because of its more lipophilicity.

Animals↗
PubMedDate not supplied

Role of poloxamer 188 during recovery from ischemic spinal cord injury: a preliminary study.

Paraplegia following aortic surgery is not a common event. When it does occur it significantly alters the patient's outcome. Poloxamer 188 (P188) has been shown in the experimental animal to increase regional blood flow to ischemic areas. In order to investigate its protective effect during aortic cross-clamping, 23 animals were randomized to two groups (placebo n = 11, P188n = 12) and received an intravenous injection of placebo or P188 (200 mg/kg), and underwent occlusion of the thoracic aorta and both subclavian arteries for a period of 13 minutes. They were then connected to an intravenous pump delivering either placebo or P188 (250 mg/kg/hr at a rate of 0.942 ml/hour) for 48 hours. Hindlimb function was appraised, daily for 30 days, by a lesion score (0-15). Spinal cord injury was assessed by a histologic score (0-3) based on the degree of gray and white matter gliosis, number of motor neurons, and white matter myelination. Analysis of variance for repeated measures did not reveal significant difference between P188 and placebo groups (P = 0.66). Similarly, the mean histologic scores (placebo = 1.54 +/- 0.41 SE, P188 = 1.08 +/- 0.33 SE) did not differ (Wilcoxon, P = 0.43). We conclude that intravenous administration of P188 before, during, and for 48 hours after aortic cross-clamping does not prevent paraplegia or improve the long term neurologic outcome.

Animals↗
PubMedDate not supplied

Episodic acute care costs: linking inpatient and home care.

STUDY OBJECTIVE: To develop a measure of an acute care "episode of care" that incorporates hospital and home care portions of care, and to measure the costs of such episodes. DESIGN: Patient level data from a home care program and an acute care hospital were linked using patient health insurance identification numbers. The linked database contained information on inpatient case mix, home care patient classification (i.e., type of care) and cost data for both settings. Data by patient classification were analyzed. MAIN RESULTS: Patterns of resource use were very different for medical and surgical cases, home care costs being 25% of a medical episode and only 5% of a surgical episode. For surgical cases, the marginal cost of an extra surgical day is about equal to the marginal cost of an extra short-term home care case (i.e., a one-day reduction in a surgical inpatient length of stay would cover the cost of a home care stay). Medical cases would require a three-day reduction in inpatient cost.

Acute Disease↗
PubMedDate not supplied

Tumorigenicity, oncogene transfection, and radiosensitivity.

PURPOSE: Reports that the incorporation of exogenous oncogenes confer radioresistance have excited interest and controversy. We investigate whether human cell lines transformed to a malignant phenotype by gamma-rays or by chemicals became radioresistant. MATERIALS AND METHODS: Rodent intestinal epithelial cells immortalized by the HPV virus, human immortalized bronchoepithelial cells and their malignant counterparts transformed by alpha-particles, uroepithelial cells and their malignant counterparts transformed either by alpha-particles or methylcholanthrine-4, and osteosarcoma cells and their nonmalignant counterparts into which the Rb gene had been introduced were used. Dose response curves for all of these cell lines were obtained by exposure to cesium 137 gamma-rays at a dose-rate of 1.18 Gy/min. RESULTS: There was a dramatic increase in resistance to gamma-rays when H-ras was transfected into rodent intestinal epithelial cells. By contrast, in the case of the three human cell lines used, no consistent or significant change of radiosensitivity occurred when normal cells were transformed to a malignant state by alpha-particles or by a chemical carcinogen. CONCLUSIONS: Experiments involving the introduction of foreign oncogenes to cause tumorigenicity and accompanying radioresistance do not have direct relevance in human tumors. In a number of different instances, the conversion to malignancy by means that more closely reflect what happens in practice (i.e., by radiation or a chemical carcinogen) is not necessarily accompanied by an increased radioresistance to low doses of radiation.

Alpha Particles↗