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Biomedical subjects

L Taylor

Publications and source records attributed to L Taylor.

At least 289 records · Page 16Linked to original sources
PubMed1980

Stimulation of prostaglandin synthesis by ascorbic acid via hydrogen peroxide formation.

Ascorbic acid causes an increase in prostaglandin (PG) synthesis in human lung fibroblasts in culture. This is accompanied by an increase in fatty acid release from cellular lipid stores. The effects of ascorbic acid on prostaglandin synthesis and fatty acid release are erased if the cultures are treated simultaneously with catalase, but not if treated with superoxide dismutase. The action of catalase points to a role of hydroperoxides in the synthesis of prostaglandins. The addition of hydrogen peroxide itself increases prostaglandin synthesis by these cells.

Arachidonic Acids↗
PubMed1980

The mechanism of thrombin-induced platelet factor 4 secretion.

We have measured thrombin-induced secretion of platelet factor 4 antigen (PF4) and simultaneously followed its intracellular translocation by immunofluorescence. In permeable resting platelets, speckled intracellular immunofluorescent staining for PF4 was observed. Addition of thrombin to washed platelets at 22 degrees C resulted in secretion of PF4 and formation of large (approximately 0.5 micrometer) immunofluorescent masses. These masses moved to the cell periphery during secretion and were virtually absent at the conclusion of secretion. Ultrastructural examination of thrombin-treated platelets revealed vacuoles corresponding in size, shape, and time of occurrence to the large immunofluorescent masses of PF4. These vacuoles contained PF4 by immunoferritin staining of frozen thin sections; they therefore appear to represent the ultrastructural counterpart of the large PF4 masses. When intact cells were stained for PF4 after thrombin addition, only 5.6% of the large masses stained. Thus, during secretion, PF4 antigen is consolidated into large closed pools that appear as vacuoles in the electron microscope.

Antigens↗
PubMed1979

A unit for source and protective isolation in a general hospital.

An isolation unit consisting of 12 ventilated cubicles was investigated over 18 months. Out of 462 patients admitted, 262 (57%) required source and 200 (43%) protective isolation. Admissions of patients with staphylococcal sepsis fell from 16 in the first three months to six in the last three months. Staphylococcus aureus was recovered from 12% of nurses' fingers and often in small numbers from protective clothing and uniforms, but only two patients acquired a strain from a nurse or another patient. Gram-negative bacilli were rarely recovered from hands or protective clothing of nurses, and there was no evidence of spread of infectious diseases. This inexpensive unit, with simple but efficient isolation-nursing techniques, successfully prevented the spread of infection.

Air Microbiology↗
PubMed1979

Prostaglandin production by type II alveolar epithelial cells.

Prostaglandin production was studied in fetal and adult type II alveolar epithelial cells. Two culture systems were employed, fetal rat lung organotypic cultures consisting of fetal type II cells and monolayer cultures of adult lung type II cells. Dexamethasone, thyroxine, prolactin and insulin, hormones which influence lung development, each reduced the production of prostaglandin E and F alpha by the organotypic cultures. The fetal cultures produced relatively large quantities of prostaglandin E and F alpha and smaller quantities of 6-keto-prostaglandin F1 alpha and thromboxane B2. However, prostaglandin E2 production was predominant. In contrast, the adult type II cells in monolayer culture produced predominantly prostacyclin (6-keto-prostaglandin F1 alpha) along with smaller quantities of prostaglandin E2 and F2 alpha. The type II cells were relatively unresponsive to prostaglandins. Exogenously added prostaglandin E, had no effect on cell growth, and only a minimal effect on cyclic AMP levels in the monolayer cultures.

Animals↗
PubMed1979

Divergent views of hospital staff on detecting and managing hypertension.

A questionnaire about detecting and managing hypertension was answered by 76 out of 110 (69%) doctors and 116 out of 195 (63%) qualified nurses in a large hospital. There was no general agreement on the method of taking diastolic blood pressures or on the level of hypertension requiring treatment. Most of the clinicians treated mild hypertension, although no proof exists that such treatment is beneficial. Almost everyone questioned agreed that measuring blood pressure in all patients attending hospital is important. Agreement should be reached, however, on which phase of diastolic blood pressure should be used.

Attitude of Health Personnel↗
PubMed1979

Wound sepsis following gastrointestinal surgery: a comparison of topical and two-dose systemic cephradine.

A prospective study of the effect of the route of administration of prophylactic antibiotic on the wound infection rate following gastrointestinal surgery was performed. Patients were randomly allocated to one of three groups: group 1 received no form of antibiotic prophylaxis; group 2 received 1 g of cephradine applied topically to the wound at closure; group 3 received 1 g of cephradine intravenously at induction of anaesthesia and a further intravenous dose of 500 mg 4 h later. Wound infections occurred in 12 of 83 patients in the control group (14.5 per cent), in 6 of the 83 patients in the group who received topical antibiotic (7.2 per cent) and in 3 of the 82 patients who received systemic antibiotics (3.6 per cent). Only the group who received systemic antibiotic showed a statistically significant reduction in the incidence of wound infections compared with the control group (P = 0.03).

Administration, Topical↗
PubMed1979

Unsaturated fatty acid effect on cyclic AMP levels in human embryo lung fibroblasts.

The addition of arachidonic acid at 250 muM to cultures of human embryo lung fibroblasts (IMR-90) increases cellular cyclic AMP levels within 5 minutes to approximately 15-fold over basal. Other unsaturated fatty acids, 11, 14, 17-eicosatrienoic, linoleic, 8, 11, 14-eicosatrienoic and oleic also cause similar rapid elevation of cellular cyclic AMP. During this time interval, no detectable conversion of the added linoleic or arachidonic acids to prostaglandin is observed. These cells produce prostaglandins at measurable concentrations in response to treatment with ascorbic acid or bradykinin. Saturated fatty acids have no influence on cyclic AMP levels in these cells. This effect of unsaturated fatty acids on cellular cyclic AMP levels varies with the cell type. For example, smooth muscle and endothelial cells obtained from the calf pulmonary artery show very little or no increase in cellular cyclic AMP upon exposure to arachidonic acid.

Animals↗
PubMed1978

Plasma membrane associated metabolic parameters and the aging of human diploid fibroblasts.

Substrate uptake, portions of the cyclic AMP system, membrane fluidity and cellular phospholipid content are some of the parameters which are structurally associated with the plasma membrane and which have been linked to the control of cell proliferation. These parameters were studied with respect to cellular aging of human embryo lung fibroblasts (HELF) in culture. We observed in late passage an increase in the rate of uridine transport and in cellular cyclic AMP levels. These results were examined in relation to the increase in cell volume which occurs in senescing HELF. We also observed an increase in Vmax of uridine transport, and a decrease in the Km of cyclic AMP phosphodiesterase (PDE) as quiescent, passage 18-25, HELF were stimulated to divide with fresh serum. A similar effect of serum occurred in late passage (p. 43) cells despite the inability of these late passage cultures to undergo further proliferation. There was no change in cAMP-PDE activity with increasing passage number suggesting that the observed alterations of the cAMP levels, basal and in response to extracellular effectors, were due to alterations in the adenyl cyclase system. We observed no change in senescent HELF in membrane fluidity or phospholipid and neutral fat content.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1977

Effects of prostaglandin on substrate uptake and cell division in human diploid fibroblasts.

PG (prostaglandin) E1 inhibits the uptake of iridine, thymidine, 2-deoxy-D-glucose and L-isoleucine into human diploid WI38 fibroblasts. The inhibition occurs within seconds of the addition of the prostaglandin to the culture. PGE2, PGF1alpha and PGF2alpha behave similarly. Arachidonic acid and 8,11,14-eicosatrienoic acid also decrease uptake in the presence or absence of indomethacin. Other unsaturated fatty acids such as oleic acid, linoleic acid and linolenic acid are essentially inactive. Ricinoleic acid (the 9-hydroxyoleic acid), however, inhibits uptake to about the same degree, at concentrations similar to those of the prostaglandins. Results indicate that this rapid blockage by the prostaglandins and certain fatty acids is not cyclic AMP-mediated. For example, although PGF1alpha and PGF2alpha are much poorer stimulators of cyclic AMP formation than are PGE1 and PGE2, they are nevertheless effective inhibitors of substrate uptake. Adrenaline, a very effective stimulator of cyclic AMP formation in the cells, is not inhibitory. Also, the addition of 8-methylthioadenosine 3':5'-cyclic monophosphate (methylthio cyclic AMP) to the culture, methylthio cyclic AMP decreases the uptake of nucleotides into cultures undergoing active cell division, approximately to values found in quiescent cultures. PGE1 also has this effect on cells undergoing active growth. This gradual decrease is substrate uptake caused by PGE1 appears to be a separate event from its initial rapid inhibition of uptake.

Cell Division↗