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Biomedical subjects

J L Gainer

Publications and source records attributed to J L Gainer.

At least 37 records · Page 2Linked to original sources
PubMed1991

A model for the prediction of partition coefficients in aqueous two-phase systems.

A mathematical model has been developed to predict partition coefficients for aqueous two-phase systems. The model is based on a previously-developed equation for partitioning which arises from an osmotic pressure viral expansion. The model suggests that the properties of importance are the concentration difference of one of the phase-forming components, such as a polymer, and the hydrophobicity of the solute relative to the hydrophobic-hydrophilic difference between the two phases. Several two-phase systems have been studied, with a particular emphasis on the poly(ethylene glycol)/magnesium sulfate system. Numerous solutes, including peptides, were used in this system and their partition coefficients show good agreement with the model.

Mathematics↗
PubMed1988

The carotenoid crocetin enhances pulmonary oxygenation.

Rabbits anesthesized with urethan and subjected to mild hypoxia (60-70 Torr arterial PO2) through a reduction of the minute volume were injected with a carotenoid compound, crocetin, or saline. The increased PO2 in the arterial blood seen subsequently with crocetin is attributed to increased diffusion through plasma. Blood flow rates remained constant and were unaffected by crocetin.

Animals↗
PubMed1987

Hypoxia and atherosclerosis: re-evaluation of an old hypothesis.

It was hypothesized over 40 years ago that a decrease in the oxygenation of the vascular wall might somehow be involved in atherogenesis. Recent studies concerning the mechanism of oxygenation indicate that diffusion through plasma is of major importance, meaning that a moderate, prolonged hypoxia could be induced by small decreases in the oxygen diffusivity. Combining all of this leads to a comprehensive theory of atherosclerotic change, indicating how aging, smoking, diabetes, hypercholesterolemia and hypertension are correlated with the disease, and suggesting methods of prevention (or reversal).

Arteriosclerosis↗
PubMed1986

Carotenoid compound crocetin improves cerebral oxygenation in hemorrhaged rats.

The carotenoid compound crocetin has been shown to increase oxygen diffusivity in vitro. In the present study the effect of crocetin on tissue oxygenation was examined in the cerebral cortex of rats subjected to hemorrhage. Twelve male Sprague-Dawley rats were anesthetized with pentobarbital and ventilation was controlled (PaCO2 = 33 mm Hg). A craniotomy was performed and the animals were hemorrhaged (20% of estimated total blood volume). Six of 12 animals then received a bolus of crocetin (2 U in 0.1 ml saline); the remaining animals received saline (0.1 ml i.v.) only. Values for mean arterial pressure. PO2, PCO2, pH, and hematocrit did not differ in rats that received either saline or crocetin. Tissue oxygen tension (PtO2) was measured at approximately 170 locations in the parietal cerebral cortex of each rat by a platinum-oxygen microelectrode technique. Results were compared by PtO2 frequency histograms. Crocetin as compared with saline treatment resulted in a right shift of the PtO2 frequency distribution and a significant decrease in the frequency of occurrence of low PtO2 values. The average of individual median PtO2 values was significantly greater in crocetin-treated animals as compared with those receiving saline (7.6 +/- 1.7 vs. 3.2 +/- 1.2 mm Hg, respectively). The results suggest that the carotenoid compound crocetin improves tissue oxygenation in the cerebral cortex of hemorrhaged rats.

Animals↗
PubMed1980

Increasing alveolar oxygen transport.

The use of a carotenoid compound, crocetin, as an oxygen diffusion enhancer was studied in both in vivo and in vitro conditions. For the in vivo experiments, the oxygen-enhancing characteristics of crocetin were studied using emphysemic rats. The in vitro experiments also verified the enhanced diffusion of oxygen through plasma due to crocetin.

Animals↗
PubMed1977

The role of oxygen diffusivity in biochemical reactions.

It has been shown that increasing protein concentrations can decrease oxygen diffusion in 3 in vitro systems. We postulate that it is possible, and in some circumstances probable, that diffusion might be a rate limiting step in both in vitro and in vivo biological systems.

Animals↗
PubMed1976

Steroids and oxygen solubility.

Determinations of oxygen solubility in serum were made utilizing various concentrations of corticosteroids in the serum. Within a certain concentration range dexamethasone and betamethasone caused an increase in oxygen solubility. None of the other steroids tested demonstrated this property.

Betamethasone↗