Search PubMed⌕ Search

Biomedical subjects

J Whiting

Publications and source records attributed to J Whiting.

49 records · Page 3Linked to original sources
PubMed1983

Characterization of 11-HETE and 15-HETE, together with prostacyclin, as major products of the cyclooxygenase pathway in cultured rat aorta smooth muscle cells.

Arachidonic acid is the precursor of several potent derivatives that regulate physiological functions in the cardiovascular system. Thromboxane (TXA2) and prostacyclin (PGI2) are synthesized by the cyclooxygenase enzyme. The proaggregatory and vasoconstrictive TXA2 produced by platelets is opposed in vivo by the antiaggregatory and vasodilating activity of PGI2 synthesized by blood vessels. Arachidonic acid is also converted via a 5-lipoxygenase to leukotrienes, the vasoconstrictive components of SRSA. We have shown that this latter pathway is regulated by 15-HETE, a product of the 15-lipoxygenase present in lymphocytes. Confluent cultures of rat aorta smooth muscle cells (RSM) were superfused briefly with [14C]arachidonic acid. The products were isolated and analyzed by thin-layer chromatography-radioautography, high performance liquid chromatography, and gas-liquid chromatography-mass spectrometry. Prostacyclin (PGI2) was identified as the major product both by its biological properties in a platelet aggregation assay and by the mass spectrum of its tetra-trimethylsilylether-methyl ester derivative. Minor quantities of PGE2, PGD2, and PGF2 alpha were also synthesized. Three other compounds with chromatographic properties of mono-hydroxy eicosanoic acids were also formed in major amounts. These were shown to be cyclooxygenase products since their synthesis, together with that of prostacyclin, was blocked by the cyclooxygenase inhibitors aspirin (0.2 mM) and indomethacin (10 microM). Quantities of the hydroxy-eicosanoids were isolated from large scale incubations by silicic acid chromatography. Following methylation and reduction with platinum oxide/H2, the compounds were converted to their trimethylsilylether derivatives and analyzed by gas-liquid chromatography-mass spectrometry. The compounds were identified as 11-hydroxy-5,8,12,14-eicosatetraenoic acid (11-HETE), 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE), and hydroxy-5,8,10-heptadeca-trienoic acid (HHT) by simultaneous ion monitoring of characteristic ions at M/e ratios of 287, 258, 229 for 11-HETE and 343, 314, 173 for 15-HETE, and by comparison with the mass spectra of authentic samples. Rat smooth muscle cells, prelabeled by 24-hour incubation with [14C]arachidonic acid, released large amounts of prostacyclin together with enhanced amounts of 11- and 15-HETE in response to physiological levels of thrombin (0.5-5 units/ml). These experiments demonstrate that, in addition to the thromboxane antagonist prostacyclin, vascular smooth muscle cells produce significant quantities of the leukotriene inhibitor 15-HETE via the cyclooxygenase pathway in response to physiological stimuli such as thrombin. The release of both prostacyclin and 15-HETE by vascular smooth muscle cells may thus play an important role in vascular homeostasis.

Animals↗
PubMed1981

Patient education in the hospital setting.

S.G. Rosenberg outlines three types of problems which occur in the care of the chronically ill. The first of these is clinical failure which occurs with an unavoidable exacerbation of the illness. Second is medical failure which occurs when technology cannot provide a cure. And third is an education failure when the patient will not follow the prescribed regime. This can result from either a choice made by the patient or family not to comply, or from a lack of knowledge on the part of the patient, or the lack of a planned education approach as part of the patient's care. Compliance is often suggested as the outcome to be measured as the result of any educational effort. This is valid, in part, but there are other outcomes equally important. These include the independence achieved through knowledge, and the assumption of responsibility for self-care. It is one thing to present information, and quite another to have the patient and family demonstrate acceptance and make changes in general lifestyle and daily routines. The responsibility for the treatment regime and change in behavior ultimately rests with the patient and family. The health professional is responsible for providing support and ensuring access to the tools (information, skills, and attitudes) which the patient and family require. Patient education is vital. An acute care setting provides numerous opportunities to initiate and continue the education process for both inpatients and outpatients.

Communication↗
PubMed1980

Aspirin: an unexpected side effect on prostacyclin synthesis in cultured vascular smooth muscle cells.

Monolayer cultures of rat aorta smooth muscle cells synthesized the anti-aggregatory substance prostacyclin via the cyclooxygenase pathway from 14C-labeled arachidonic acid. The product was identified both by bioassay and by mass spectrometry. Labeled cells produced prostacyclin only when exposed to the initiator thrombin: treatment with therapeutic concentrations of aspirin (0.2 millimolar) for 30 minutes completely destroyed the cells' ability to synthesize prostacyclin. Prostacyclin synthesis from exogenous arachidonic acid recovered fully within 1 to 2 hours by a cycloheximide-sensitive process. Thrombin responsivness, which was permanently impaired in confluent nondividing cultures, recovered substantially and within 24 hours only when cells were stimulated to divide by subculturing. These results indicate that resting vascular cells can rapidly synthesize new cyclooxygenase, but that aspirin destroys additional components of the prostacyclin system which can only be replaced during cell division.

Animals↗
PubMed1973

Aerobic bacteria occurring in the hind-gut of the cockroach, Blatta orientalis.

Methods are described for the isolation and identification of aerobic bacteria occurring naturally in the hind-gut of the cockroach Blatta orientalis captured from a number of wild sources, to establish whether or not human pathogens occurred naturally within the gut. During the investigation an organism was frequently found which could not be classified in any described species, and for which we propose the name Escherichia blattae.

Aerobiosis↗
PubMed1973

Laboratory transmission of enterobacteriaceae by the oriental cockroach, Blatta orientalis.

Methods of maintaining and feeding and of infecting cockroaches with pathogenic organisms were investigated.Cockroaches fed on known concentrations of Escherichia coli O119, Esch. coli O1, Alkalescens Dispar O group 2 and Shigella dysenteriae 1 (Shiga's Bacillus) were maintained in Petri dishes. The effect of various diets on the survival of these organisms within the hind-gut and faeces was observed. With a ;normal' diet of gruel Esch. coli O119 was isolated for up to 20 days, Esch. coli O1 for 17 days and ADO 2 for 15 days. Sh. dysenteriae 1 was isolated only sporadically to the third day.

Animals↗
PubMed1966

Some differences in uveal reactions between cats and rabbits.

1. Miosis was observed after enucleation in unopened eyes from normal or atropinized, atropinesterase-free rabbits. Such a phenomenon was not seen in enucleated cat eyes, in which the pupils remained widely dilated, whether atropine had been administered or not.2. Pre-treatment of the animals with reserpine did not alter this difference between the species.3. The difference does not appear to be due to absence of irins from the cat iris, since aqueous extracts of cat irides contained a smooth-muscle-contracting activity (cat irin) extractable into ether at pH 3 and therefore consisting of lipid acid(s).4. The difference is not due to insensitivity of the cat sphincter pupillae muscle to irins, since injections of ether-purified cat or rabbit irins into the anterior chamber of enucleated cat eyes kept at room temperature constricted the pupil; injections of histamine were ineffective.5. In experiments on animals treated with atropine +/- mepyramine I.V., photographic measurements revealed a further difference, namely in the speed of miosis after stroking the iris in vivo. The response started later in the cat, and developed more slowly, but often to a fuller extent than in the rabbit.6. In a proportion of cat eyes there was little or no change in intraocular pressure after irritation of the iris adequate to induce maximum pupillary constriction; this was so whether mepyramine had been administered or not.7. Possible reasons for the above species differences are discussed.

Animals↗
PubMedDate not supplied

Effects of a positron-emitting vanadium-48 nitinol stent on experimental restenosis in porcine coronary arteries: an injury-response study.

BACKGROUND: The major limitation of coronary stenting is restenosis due to exaggerated neointimal thickening. We evaluated a positron-emitting V48 nitinol stent in a porcine coronary model of restenosis. METHODS AND RESULTS: Pigs (n = 16) received a control nonradioactive and a V48 stent (1.5 or 10.6 muCi) randomized to the left anterior descending artery (LAD) and right coronary artery (RCA). Histology, morphometric variables, and strut injury scores were evaluated after 32 days. Peristrut fibrinoid deposits were greater in the high-dose group (p < 0.0001). Control stent area stenosis (AS) and mean neointimal thickness (NIT) correlated with injury (r = 0.81 and 0.79, respectively). Higher-dose stents reduced AS by 20% (0.57 +/- 0.13 vs. 0.71 +/- 0.16; p = 0.029) and mean NIT by 35% (0.44 +/- 0.16 vs. 0.71 +/- 0.24mm; p = 0.001) compared with controls. Lower-dose 1.5-muCi stents did not differ from controls. NIT over individual struts was reduced in the high-dose group compared with controls by 0.18 mm for grade 1 injury, 0.31 mm for grade 2, and 0.38 mm for grade 3 (p < 0.02 for all comparisons). CONCLUSIONS: 1.5-muCi V48 nitinol stents did not influence vessel histology or restenotic parameters in pig coronary arteries. In contrast, 10.6-muCi stents created a distinctive histological picture consisting of increased fibrinoid deposits on the neointimal-facing side of the struts without cellular organization. Higher dose radioactive stents significantly reduced AS and mean NIT. The reduction in neointimal thickening was greatest when the depth of strut penetration into the vascular wall was most severe.

Alloys↗
PubMedDate not supplied

Leakage of a liquid 188Re-filled balloon system during intracoronary brachytherapy. A case report.

We are reporting the first case of an accidental radioactive 188Re leakage of a liquid-filled balloon system. Different analytical methods estimated that approximately 4 mCi 188Re were released. The radiation burden was reduced considerably by the combined therapy with perchlorate and forced volume diuresis. Estimated exposures to all organs were very low with 1.8 rad. A total body nuclear scintigraphy demonstrated uniform 188Re distribution, without specific organ concentration.

Aged↗
PubMedDate not supplied

Pin-site care.

Explore the source record for details and available documents.

External Fixators↗