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Biomedical subjects

F Gonzalez

Publications and source records attributed to F Gonzalez.

10 recordsLinked to original sources
PubMed1979

Arterial PCO2 response to intravenous CO2 in awake dogs unencumbered by external breathing apparatus.

The steady-state arterial CO2 tension (PaCO2) was examined during control and intravenous CO2 loading in awake dogs unencumbered by any breathing apparatus. The dogs inhaled air while undergoing intravenous CO2 loading, and we estimated the gain, delta VA/delta PACO2. CO2 was introduced into the systemic venous blood via a membrane gas exchanger in a femoral arteriovenous shunt circuit, and the extracorporeal blood flow was maintained constant at 0.5 l/min. A total of 11 experiments were performed in 3 dogs comprising 93 control observations and 83 CO2 loading observations. Intravenous CO2 produced a significant increase in the steady state PaCO2, a finding consistent with our previous study in tracheostomized awake dogs. We conclude that intravenous CO2 produces hypercapnia in the awake dog with an intact airway unencumbered by external respiratory apparatus.

Acidosis, Respiratory↗
PubMed1978

The A2B2 hybrid isozyme of phosphofructokinase.

The hybrid isozyme of phosphofructokinase, A2B2, was formed by incubation of rabbit muscle enzyme. A4, and rabbit liver enzyme, B4, in the presence of sodium citrate at neutral pH. The enzyme composition of the resulting mixture of A2B2 and the homoprotomeric forms was identical to that found in rabbit adipose tissue extracts. Hybrid formation, which apparently proceeds by way of dimers, can be blocked by fructose-1,6-P2, fructose-6-P, and high concentrations of MgATP. The A2B2 isozyme was separated from A4 and B4 by ion exchange chromatography. The kinetic regulatory properties of A2B2 were compared with those of A4, B4, and a 1:1 mixture of A4 and B4. ATP inhibition of A2B2 was intermediate between that observed with A4 and B4 and was clearly not identical to a simple summing of the effects of A and B subunits. Similar comparisons were made using other phosphofructokinase inhibitors, citrate, 2,3-P2-glycerate, and P-creatine. In each case the observed inhibition was intermediate between the observed with A4 and B4. The existence in a number of tissues of phosphofructokinase A2B2 provides added diversity to the regulatory mechanisms of glycolysis.

Animals↗
PubMed1978

Respiratory responses to intravenous and intrapulmonary CO2 in awake dogs.

Ventilatory responses to CO2 inhalation and CO2 infusion were compared in the awake dog. The CO2 was introduced directly into the systemic venous blood via a membrane gas exchanger in a femoral arteriovenous shunt circuit, and the extracorporeal blood flow, QX, was maintained constant at one of two rates: low, 0.5 l/min; or high, 2.0 l/min. A total of 13 experiments was performed in four dogs comprising 50 control and 25 inhalation and infusion observations at each of the two flow rates. Comparison of CO2-response curve slopes, S = delta V E/delta PaCO2, between CO2 inhalation and infusion showed no significant difference either within or between flow rates. The mean value of S for all conditions was 1.88 l/min per Torr with a 95% confidence interval of 1.66 -2.14. An independent additive ventilatory drive amounting to 28% of low-flow control VE was found at the highflow rate. We conclude that at constant blood flow the responses to both CO2 inhalation and infusion are hypercapnic and not significantly different.

Animals↗
PubMed1977

Effects of naturally occurring sugars on Ehrlich ascites tumor growth in mice.

The growth of Ehrlich ascites tumor cells in Swiss mice was modified by the addition of certain naturally occurring sugars to the drinking water or by ip inoculation of mice after infection. D-Mannose, D-ribose, and D-glucosamine produced the most striking antitumor effects, increasing significantly the survival rate in mice so treated.

Animals↗
PubMed1977

Mechanism of respiratory responses to intravenous NaHCO3, HCl, and KCN.

We studied the mechanism by which respiratory responses are produced by rapid injection of NaHCO3, HCl, or KCN into the superior vena cava of lightly anesthetized dogs. To estimate independently circulatory transit time to receptor sites, the solutions were injected at 0 degrees C and their arrival time at the ascending aorta and carotid sinus was detected by thermocouples. All of the ventilatory responses were observed to begin after the substances had reached the ascending aorta and 94% began after the carotid sinus had been reached. The injections were repeated following bilateral vagotomy and/or carotid body resection. Vagotomy produced no significant changes in ventilatory responses, but carotid body resection considerably reduced them. Following both procedures, few ventilatory responses were observed, and the time lag to the onset of the response increased greatly. We conclude that all of the observed ventilatory responses can be accounted for by the known arterial and central chemoreceptors, and that no evidence for pulmonary chemoreceptors was obtained.

Animals↗
PubMed1977

Acute leukemia in multiple myeloma.

Of 476 patients with multiple myeloma treated during a 9-year period, 11 developed acute myelogenous leukemia or sideroblastic anemia. In all, the myeloma was in remission from chemotherapy with melphalan-prednisone combinations that had been continued for a median duration of 3 years. The incidence of acute leukemia or sideroblastic anemia was about 100 times higher than found in normal individuals of the same age. In all patients studied, major cytogenetic abnormalities were present, with hypodiploidy and evidence of chromosomal damage being noted most frequently. The frequency and nature of the chromosome changes were attributed to effects resulting from the prolonged drug therapy. These findings supported the long-term follow-up of selected patients with myeloma without any chemotherapy when marked degrees of remission followed the initial treatment courses.

Aged↗