Publications by authors named "Colvin J"

The effects of exercise on insulin action were evaluated in epididymal adipocytes from 9-mo and 26-mo-old rats. Exercised animals were given voluntary access to running wheels at 6 mo of age. Comparisons were made among these animals, freely eating sedentary rats, and sedentary animals maintained at body weights comparable to those of the runners.

View Article and Find Full Text PDF

In a double-blind, placebo controlled study ketanserin, a serotonin S2 antagonist, was administered to hypertensive patients who had undergone coronary artery bypass surgery. Patients were allocated randomly to receive placebo or ketanserin at an infusion rate of 0.05, 1 or 2 mg kg-1 h-1.

View Article and Find Full Text PDF

Hypertension in the early postoperative period after cardiopulmonary bypass is associated with increased morbidity, and is commonly managed by the infusion of short-acting vasodilators. Automatic arterial blood pressure control by closed-loop infusion has been shown to be superior to manual control in several studies. The investigators have developed a closed-loop arterial pressure control system based on the Atari 1040ST microcomputer (Atari, Sunnyvale, CA).

View Article and Find Full Text PDF

Hypertension after cardiac surgery is common and is associated with increased morbidity. It is usually managed by the infusion of short acting vasodilators. The use of a closed-loop computer system to control the infusion of a vasodilator has been shown to compare favourably with manual control.

View Article and Find Full Text PDF

Arterial hypertension after cardiac surgery is common and is associated with increased morbidity. Glyceryl trinitrate may be a more suitable agent for control of hypertension than sodium nitroprusside. We have developed a closed-loop system for the Atari 1040ST microcomputer to control arterial pressure by the simultaneous infusion of two vasodilators under computer control.

View Article and Find Full Text PDF

Many neurotransmitters, hormones and growth factors act at membrane receptors to stimulate the phosphodiesteratic hydrolysis of phosphatidyl-inositol 4,5-bisphosphate generating the comessengers inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and diacylglycerol. Diacylglycerol stimulates protein kinase C3 while Ins(1,4,5)P3 is postulated to activate specific receptors leading to release of intracellular calcium, probably from the endoplasmic reticulum. In recent preliminary reports, Rubin and associates detected 32P-Ins(1,4,5)P3 binding to liver and adrenal microsomes and to permeabilized neutrophils and liver cells.

View Article and Find Full Text PDF

Manual systems for requisitioning services are gradually being replaced with data entry terminals on the nursing divisions. These systems claim greater accuracy and timeliness of response, but the capital investment necessary is oftentimes unwarranted, as well as being cost prohibitive for many hospitals.

View Article and Find Full Text PDF

From the temperature dependence of the Orbach relaxation rate of the paramagnetic center in horseradish peroxidase (HRP), we deduce an excited-state energy of 40.9 +/- 1.1 K.

View Article and Find Full Text PDF

Electron spin relaxation data from five ferric proteins are analyzed in terms of the fractal model of protein structures. Details of this model are presented. The results lead to a characterization of protein structures by a single parameter, the fractal dimension, d.

View Article and Find Full Text PDF

Methanobacterium bryantii was found to undergo rapid lysis when grown in a prereduced chemically defined medium under H2-CO2 (4:1, vol/vol). The addition of 20 mM MgCl2 to the medium gave, rather than rapid lysis, a gradual formation of phase-dark spherical bodies which in thin section appeared as true protoplasts. In general, the protoplasts were stabilized by divalent but not monovalent cations and, unlike whole cells, were sensitive to lysis by Triton X-100.

View Article and Find Full Text PDF

In the transportation of patients with penetrating eye injuries, vomiting, hypoxia and infection are the main causes of serious ocular complications, and efforts must be directed at minimizing their occurrence. As long as definitive microsurgical repair is undertaken within 24 hours of injury, an optimal surgical result can be expected. In this paper full directions are given for the patient's immediate treatment.

View Article and Find Full Text PDF

Cultures of cellulose-deficient cells ofAcetobacter xylinum that were isolated from solid medium revert from the cellulose-deficient condition to the normal, cellulose-producing, form after five transfers in liquid medium. In addition, serial cultures of initial mixtures of cellulose-deficient cells and normal cells in the ratio of 9 to 1 show a rapid decrease in the proportion of deficient cells so that after seven transfers in liquid medium there is less than, 1% of cellulose-deficient cells. These results demonstrate that, in liquid medium, cells which are normal in cellulose production overgrow those which are deficient in this capacity.

View Article and Find Full Text PDF

The mechanism of formation of cellulose-like microfibrils by a non-soluble, particulate enzyme and uridine diphosphoglucose (UDPG) in a cell-free system from Acetobacter xylinum was studied by transmission electron microscopy and X-ray diffraction. The suspension of particles to which the enzyme is adsorbed is composed of whole, dense ovoids, 50-250 nm long when wet, of fragments of the ovoids, and amorphous substance. There is a typical unit membrane around each ovoid but initially there is no trace of fibrillar material in the suspension.

View Article and Find Full Text PDF

The results of differential, thermal analysis of a soluble, beta (1 leads to 2)-branched, beta (1 leads to 4)-D-glucan isolated from cultures of Acetobacter xylinum are consistent with previous conclusions about its structure. The O-acetyl content of the polymer is 8.3% which corresponds to a maximum substitution of one acetyl group per three glucose residues.

View Article and Find Full Text PDF

The ultrastructure of the cells of the major component of an enriched culture of a presumed methanogen which utilized acetic acid was studied by transmission and scanning electron microscopy. The filaments were composed of Gram-positive, rod-shaped cells, 1--2 micrometer in length and about 0.5 micrometer in breadth, attached end to end.

View Article and Find Full Text PDF
Eye injuries and the dentist.

Aust Dent J

December 1978

The risk of damage to the eyes of the patient, the dentist and his assistant should be recognized. Protection can be achieved by the wearing of specially designed spectacles using CR 39 plastic tinted lenses. Contact lenses should be removed by patients who are to undergo general anaesthesia.

View Article and Find Full Text PDF

Development of the morphology and microstructure of colonies of Acetobacter xylinum growing on agar was studied by optical microscopy, and transmission and scanning electron microscopy. The mass of rapidly dividing cells surrounded by a sheath of cellulose microfibrils passes from a smooth spheroid to a flattened aggregate with a characteristic "pillowed" surface. This morphology is the result of a repeated extrusion of cells from the confirming sheath, followed by regeneration of a new portion of the sheath on the extrusion of cells from the confirming sheath, followed by regeneration of a new portion of the sheath on the extruded cell mass.

View Article and Find Full Text PDF