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Biomedical subjects

S P Gray

Publications and source records attributed to S P Gray.

At least 19 recordsLinked to original sources

A multiaxial computer-controlled organ culture and biomechanical device for mouse carotid arteries.

Much of our understanding of vascular mechanotransduction has come from studies using either cell culture or in vivo animal models, but the recent success of organ culture systems offers an exciting alternative. In studying cell-mediated vascular adaptations to altered loading, organ culture allows one to impose well-controlled mechanical loads and to perform multiaxial mechanical tests on the same vessel throughout the culture period, and thereby to observe cell-mediated vascular adaptations independent of neural and hormonal effects. Here, we present a computer-controlled perfused organ culture and biomechanical testing device designed for small caliber (50-5000 micron) blood vessels. This device can control precisely the pulsatile pressure, luminal flow, and axial load (or stretch) and perform intermittent biaxial (pressure-diameter and axial load-length) and functional tests to quantify adaptations in mechanical behavior and cellular function, respectively. Device capabilities are demonstrated by culturing mouse carotid arteries for 4 days.

Animals↗

Abnormalities of the bony thorax causing tracheobronchial compression.

A number of intrathoracic and extrathoracic causes of airway obstruction have been well documented in the literature. At times, tracheal compression may be caused by abnormalities of the bony thorax whose previously unrecognized significance can result in unexpected difficulties when extubation is attempted following a routine intubation. Alternatively, patients may develop progressive distress secondary to their skeletal abnormalities. We report on cases illustrating anomalies of the manubrium, sternum and spine which have caused significant, occasionally life-threatening, tracheal and bronchial narrowing including pectus excavatum and scoliosis. A protocol is presented detailing the appropriate methods of diagnosis and treatment of these types of deformities.

Adolescent↗

Hospital laboratories as profit centers.

An aggressive business venture offers one solution to the growing competition and financial pressures hospital laboratories must overcome. For such a venture to be a success, a number of issues must be carefully considered. Properly met, today's challenges in the laboratory can become tomorrow's opportunities.

Ambulatory Care↗

Effect of enprostil, a synthetic prostaglandin E2 on 24 hour intragastric acidity, nocturnal acid and pepsin secretion.

We have studied the effect of a prostaglandin E2 analogue (enprostil), on intragastric acidity, gastric acid and pepsin outputs during a 24 hour period in nine patients with duodenal ulcer in remission. Enprostil 35 micrograms bd dose inhibited 24 hour intragastric acidity by 38% and a 70 micrograms nocturnal dose by 33%. Decrease in nocturnal pepsin secretion was both volume and concentration related.

Adult↗

Kinetic assay of human pepsin with albumin-bromphenol blue as substrate.

A novel substrate, albumin complexed with bromphenol blue, has been developed for the assay of human gastric juice pepsin by a kinetic method in the Cobas centrifugal analyzer. The action of pepsin on the complex degrades the albumin and releases the dye. The change in the color of the substrate is a zero-order reaction. Human and porcine pepsin have different Km's with the new substrate. This kinetic method has a throughput of 28 tests in approximately 10 min and good precision (CV = 2.0%). Other advantages are analysis in homogeneous solution (thereby eliminating the need to separate substrate and products), lack of interference from bilirubin or phenol red, and the expression of pepsin activity in IUB enzyme units.

Albumins↗

Prediction of phenytoin dosage in epilepsy using multiple linear regression.

Analysis of plasma phenytoin in a group of patients treated for epilepsy showed that only 36% had values in the therapeutic range. The relationship between plasma phenytoin, body weight, and daily dosage of the drug were explored, and the data were analysed by multiple regression. The resultant equation, relating all three factors, were used to optimise drug dosage, and the importance of using the body weight of the patient before starting a phenytoin regimen is emphasised. An increase in the number of patients with plasma phenytoin in the therapeutic range was achieved, and the clinical value of being in that range is shown.

Body Weight↗