Biomedical subjects

A Elizalde

Publications and source records attributed to A Elizalde.

3 recordsLinked to original sources

PubMed1992

Caffeine and theophylline contractures in tonic skeletal muscle fibers of the frog.

Caffeine and theophylline evoke maintained tension in tonic skeletal muscle fibers of the frog. Their effects depended upon concentrations ranging from 0.5 to 14 mM. The resting potential of tonic skeletal fiber was unaffected by caffeine or theophylline (4 mM). Caffeine and theophylline contractures have a peak tension followed by a sustained tension, which recovered spontaneously when returned to normal solution. The peak tension and total tension (the area under tension-time curve) were reduced when the fibers were soaked in calcium-free solution. In addition the tension was reduced by calcium channel blockers (cadmium). The sustained tension was increased when external calcium was raised. These results suggest that caffeine and theophylline promote the calcium release from sarcoplasmic reticulum and probably the entry of calcium from external medium.

Animals↗

PubMed1979

Regional versus systemic heparinization.

In 12 mongrel dogs, the comparative effectiveness of systemic versus regional heparinization was studied after injecting 100 units per kilogram of heparin into a systemic vein or regionally into an artery. Activated plasma thromboplastin time was used to monitor the heparin activity, and the coagulability of blood in the general circulation was compared with the coagulability of blood in the excluded circulation distal to the vascular clamps. Both methods of heparinization were found to be equally effective. Heparin injected regionally rapidly achieves a uniform distribution in the excluded, as well as the general, circulation and, as such, cannot be called regional. There was no difference in coagulability of blood in the general circulation compared with the blood in the excluded circulation. Results of this study suggest that regional heparinization is, in fact, systemic heparinization.

Animals↗

PubMedDate not supplied

[Respiratory changes in obesity. Functional and clinical aspects. Study of 26 cases].

A study was made, at the altitude of Mexico City, of the clinic aspects and of the pulmonary function of 26 obese subjects more than 45% overweight. This excess weight habitually produces severe disturbances in pulmonary and/or heart function. In 50% of the patients, clinic, radiologic and electrocardiographic manifestations were found which suggested the existence of pulmonary arterial hypertension. This provoked right heart failure in 19% of the cases. The most constant alterations in the pulmonary volumes was the decrease in the VER, which occurred in 96% of the cases. Most of the patients had hypoxemia (92.5), which was produced mainly by the increase in venoarterial shunts. Although the clinic manifestations were similar to those described in Pickwick's syndrome, alveolar hypoventilation was presented in only a minority of the cases. No relationship was found between the degree of obesity and alveolar hypoventilation. Altitudes of 2,200 meters or more apparently favor hypoxemia in obese patients, and "protects" them from the hypercapnea. The altitude of Mexico City may be one of the reasons why alveolar hypoventilation is observed in only 15% of the cases.

Adult↗