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Biomedical subjects

J Rodríguez

Publications and source records attributed to J Rodríguez.

At least 235 records · Page 13Linked to original sources
PubMed1981

Removal of PHA from supernatants containing T-cell growth factor.

Supernatants of human PBL cultures stimulated with PHA contain a lymphokine named T-cell growth factor (TCGF). To remove the contaminant PHA from these supernatants, we have designed a simple and effective method based on the binding properties of this lectin to chicken red blood cells. This procedure completely removes the functional activities of a PHA solution, both in lectin-induced cellular cytotoxicity against erythroid targets and in DNA synthesis of fresh PBL. The TCGF activity remaining in the supernatants after absorption with CRBC is dependent on the cellular concentration employed in the preparation of the supernatants. The absorption procedure does not remove significant TCGF activity in the supernatants prepared at high cellular concentrations (5 X 10(6) cells/ml), whereas in those prepared at low cellular concentrations (1 X 10(6) cells/ml) a partial loss of TCGF activity is detected.

Animals↗
PubMed1981

[Conceptual framework for research applied to the health services].

The authors draw up a conceptual framework for applied research on health services based on the experiences of the Division of Health of the Department of Social Medicine of the Universidad del Valle, Cali, Colombia. They hope that by using this framework, people involved will be able to situate themselves in a process of this type, interpret the current role of research on health services and examine the approach that should be taken to it in the future. They bring in some elements of self-criticism in the hope of contributing to the development of research groups in this area.

Colombia↗
PubMed1978

Subunit interactions and immobilised dimers of human liver arginase.

Incubation of soluble human liver arginase (L-arginine amidinohydrolase, EC 3.5.3.1) with p-hydroxymercuribenzoate resulted in the dissociation of the enzyme into active dimers. Addition of 2-mercaptoethanol resulted in the regeneration of the tetrameric enzyme. When arginase, bound covalently to nylon, was incubated with p-hydroxymercuribenzoate, matrix-bound dimers were obtained. Incubation of these species with 2-mercaptoethanol resulted in stable, unmodified dimers. Based on this dissociation of arginase, a model with D2-symmetry is suggested for this enzyme. The specific activity, the Km value for arginine, pH optimum and the inhibition constants for ornithine and lysine were determined for monomeric, dimeric and tetrameric forms. It is concluded that the behaviour of the active sites of the monomers is not substantially altered by the interaction of these species in the oligomeric molecule.

Arginase↗
PubMed1978

Hydrogen ion CO2 and buffer capacity in brain from water depleted rats.

pH, C02 and buffer capacity of the brain and blood acid-base status were studied in (C) control and in acutely water depleted (WD) rats. WD rats developed a greater metabolic [H+] increase in brain than in blood. The results suggest that brain [H+] change is a primary metabolic reply to acute dehydration.

Animals↗
PubMed1977

Risk factors in stroke in a Mexican-American population (Houston).

To date, there is little information available on stroke risk factors in a major ethnic minority such as Mexican-Americans (M-A) in the USA. Forty-three M-A patients were admitted to The Methodist Hospital and Ben Taub General Hospital (Houston) for a 12-month period, with diagnosis of atherosclerotic stroke. Thrombosis was diagnosed in 31 patients (72%), embolism from atherosclerotic sources in seven (16.4%), and parenchymal hemorrhage in five (11.6%). Hypertension was a common risk factor in all groups, being higher in hemorrhage followed by thrombosis and embolism. Arteriosclerotic heart disease was a common risk to all stroke types. TIAs, hyperlipidemia, diabetes, associated atherosclerotic lesions, smoking, obesity, erythrocytosis and sedentary life were significantly associated with embolism; less so with thrombosis or hemorrhage. Gout was only associated with thrombosis. These results indicate similar risk factors for Anglo-saxons and M-A in the USA with some minor differences between the Mexican and the USA stroke series.

Adult↗
PubMed1976

Changes of plasma volume and plasma composition in water-deprived rats.

Plasma volume, hematocrit, protein and electrolyte concentrations in plasma were measured in control and water-deprived rats every three days after starting the experiment until the 15th day. Plasma volume variations, as related to body weight, suggest that water loss from plasma was proportional to total body water at three days and after 9 days of water deprivation. Greater plasma water than body water loss was found during the period between 3 and 9 days. Plasma protein and electrolyte variations suggest that during water deprivation there is a loss of protein, sodium and potassium from plasma, which is proportionally less than that of plasma water. Potassium, calcium and inorganic phosphorus were lost proportionally to plasma water. The variations in plasma volume changes were partially explained as due to variations in plasma protein and electrolyte concentrations.

Animals↗