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Biomedical subjects

J W Ryan

Publications and source records attributed to J W Ryan.

At least 109 records · Page 6Linked to original sources
PubMed1982

Conformational diversity of bradykinin in aqueous solution.

The 600-MHz proton nuclear magnetic resonance spectra of bradykinin, [2-dehydroproline]bradykinin, [7-dehydroproline]bradykinin, and [5-tyrosine]bradykinin in aqueous solution have been recorded and completely assigned by means of pH variation, spin-spin decoupling, and chemical shift correlations. Analysis of the spin-spin coupling constants in the main chain and in the side chains suggests that bradykinin is in rapid equilibrium among many conformers and does not show any persistent structural features such as beta turns or internal hydrogen bonds. Addition of lipids or lipid-like materials [such as sodium (trimethylsilyl)propionate] in high concentration causes changes in the spectra, indicating specific interactions with proline-7 and phenylalanine-8, as well as a change in side-chain rotameric preference.

Bradykinin↗
PubMed1982

Use of microcarriers to isolate and culture pulmonary microvascular endothelium.

Microcarriers of known diameter can be used to collect endothelial cells from microvessels of the same or slightly smaller internal diameter. The procedure is illustrated by collection of endothelial cells from rabbit pulmonary pre-capillary vessels. The lungs are perfused free of blood with physiological saline and then cold vessels. The lungs are perfused free of blood with physiological saline and then cold (4 degrees C) saline (containing EDTA, 0.02%, and microcarriers 600/ml; 40-60 micrometers diameter) is perfused via the pulmonary artery. The direction of flow is reversed periodically to collect the bead-cell harvest from the arterial side. Cold shock and EDTA cause the endothelial cells to detach from the vessels under conditions such that the cells remain attached to the microcarriers. The selective attachment to microcarriers is apparently aided by the tight fit of the beads within vessels of the same diameter. Beads do not emerge on the venous side, all being trapped at the pre-capillary level. Electron microscopic examination of lungs fixed during the perfusion shows that the beads lodge in terminal arterioles and pre-capillary vessels (approximately 40-60 micrometers in diameter, with one, sometimes incomplete, muscle layer). Endothelial cells recovered on microcarriers can be allowed to migrate on to flasks and back on to beads. The resultant cultures have an endothelial morphology and possess high levels of angiotensin coverting enzyme and carboxypeptidase N activity.

Animals↗
PubMed1982

Proliferation of pulmonary endothelial cells: time-lapse cinematography of growth to confluence and restitution of monolayer after wounding.

A fundamental characteristic of vascular endothelium is that it exists as a monolayer, a condition that must be met in both vascular growth and repair. Maintenance of the monolayer is important both for the exchange of nutrients and for interactions between blood solutes and endothelial enzymes and transport systems. We have used time-lapse cinematography to compare proliferative behavior of bovine pulmonary endothelial cells in (1) establishment of a monolayer from a low-density seed (7.5 X 10(4) cells in a 60 mm dish) and (2) restitution of a confluent monolayer (approx. 2.9 x 10(6) cells in a 60 mm dish) following a mechanical wound (removal of cells from an area 5 x 15 mm by scraping). Culture 2 was not refed after wounding. In culture 2, approx. 30% of the cells accounted for repopulation (confluence in 40 hr). In culture 1, all cells entered into division. Participating cells of culture 2 began division immediately (69 divisions/filmed area in 10 hr, vs. four divisions in culture 1). Interdivision times (IDT) were longer and relatively constant in culture 1 until near confluence; none were less than 10 h, whereas in 2, 24% of the IDT's were less than or equal to 10 hr. Remarkably, IDTs of culture 2 decreased steadily until confluence was re-established. Cell migration in culture 1 was multidirectional while direction of migration in culture 2 was always into the wound area. Mean migration rate (MIG) in culture 2 was related to the site of origin of the cells, those dividing farthest from the unwounded area had fastest MIGs. Neither culture formed more than a single layer of cells. Although the cell kinetics of cultures 1 and 2 differed, the same goal, confluence, was achieved in either case.

Animals↗
PubMed1982

Localization of carbonic anhydrase on pulmonary artery endothelial cells in culture.

Bovine pulmonary artery endothelial cells in culture possess carbonic anhydrase activity and immunoreactivity. The intact cells and cell homogenates lower the pH of 25 mM triethanolamine sulfate buffer saturated with CO2 (starting pH 8.1). The intact cells are more reactive than the cell homogenates, and the enzymic activity is enriched in association with the plasma membrane fraction. Specific immunofluorescence is obtained when the cells are incubated with rabbit antibovine erythrocyte carbonic anhydrase B and then with goat antirabbit immunoglobulin G coupled to fluorescein. At the level of electron microscopy, antibodies to carbonic anhydrase B are reactive with sites along the plasma membrane and associated caveolae. Multivesicular bodies are the only intracellular sites labeled and appear to correspond to the globular sites of intracellular immunofluorescence. Cells maintained and propagated in culture in the absence of an exogenous source of carbonic anhydrase nonetheless possess carbonic anhydrase activity, suggesting that the cells are capable of synthesizing the enzyme. Taken together, our results indicate that pulmonary artery endothelial cells possess carbonic anhydrase situated so that the enzyme could readily catalyze the dehydration of plasma HCO-3 to facilitate CO2 excretion and participate in the regulation of blood pH as central venous blood is converted into systemic arterial blood.

Animals↗
PubMed1981

Twenty-four-hour pH monitoring of esophageal function. Its use in evaluation in symptomatic patients after truncal vagotomy and gastric resection or drainage.

The incidence and character of gastrointestinal reflux after truncal vagotomy and gastric resection or drainage were studied prospectively in 42 symptomatic patients. Gastroesophageal reflux, proven by 24-hour pH monitoring, occurred in 31 patients. Initial symptoms of heartburn, regurgitation, or dysphagia were similar in patients with and without reflux. Eighteen patients had pure acid, nine had acid-alkaline, and four had pure alkaline reflux. Reflux occurred predominantly in the supine position. Esophagitis occurred only in patients with reflux and was not dependent on the pH of refluxed material. Reflux was eventually controlled by antireflux repair in 19 and by colon interposition in three patients. Twenty-four-hour esophageal pH monitoring is beneficial in evaluating symptoms after gastric surgery. It quantifies both acid and alkaline reflux, provides an objective assessment of the patient's subjective complaints, and gives a rational basis for management.

Drainage↗
PubMed1981

Value of serial measurement of serum angiotensin converting enzyme in the management of sarcoidosis.

Serial serum samples from 35 patients with histologically proved sarcoidosis were measured for angiotensin converting enzyme activity. The serum angiotensin converting enzyme (SACE) activity was compared with the clinical activity of sarcoidosis. In both the treated and untreated group, the SACE activity closely paralleled the clinical status. There was agreement between SACE index and clinical index in 81 of 101 paired observations. It appears that SACE activity is a good reflection of granulomatous activity in sarcoidosis. Once the decision has been made to treat sarcoidosis, serial SACE determinations are helpful in monitoring the dose and duration of therapy with corticosteroids.

Adult↗