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Biomedical subjects

G Garcia

Publications and source records attributed to G Garcia.

At least 127 records · Page 7Linked to original sources
PubMed1984

Interpretation of Doppler segmental pressures in peripheral vascular occlusive disease.

Measurement of Doppler segmental arterial pressures in the lower extremity using narrow pneumatic cuffs has become a standard noninvasive diagnostic technique. Correlation between arteriographic and noninvasive studies was available for 345 aortoiliac segments and 326 femoropopliteal segments. If stenoses of 50% or greater and occlusions were considered hemodynamically significant, the sensitivity to aortoiliac disease was 97%, but only 67% to femoropopliteal disease. The specificity for hemodynamically insignificant disease was 50% and 68%, respectively. Accuracy was influenced by the presence of associated aortoiliac or femoropopliteal disease. The sensitivity to hemodynamically significant femoropopliteal disease was 55% if there was associated aortoiliac disease, and 89% in its absence. In the presence of significant femoropopliteal disease, specificity for the absence of aortoiliac disease decreased from 70% to 41%.

Angiography↗
PubMed1984

Dazoxiben, a thromboxane synthetase inhibitor, in Raynaud's phenomenon.

Dazoxiben, a specific thromboxane synthetase inhibitor, was evaluated in 21 patients with Raynaud's phenomenon in a double-blind, placebo-controlled crossover experiment. Total fingertip blood flows were measured by plethysmography and capillary blood flows were measured by 133Xe disappearance rate. Subjects were studied in both a warm (28 degrees) and a cold (20 degrees) room. Arteriovenous (AV) shunt flow was estimated by subtraction of capillary flow from total flow. Ex vivo production of thromboxane B2 (TXB2) and 6-keto PGF1 alpha was determined by specific radioimmunoassay in serum from venous blood incubated for 1 hr (37 degrees). Plasma concentrations of TXB2 and 6-keto PGF1 alpha were also monitored. Dazoxiben (100 mg 4 times a day for 14 days) inhibited ex vivo TXB2 production (from 463.1 +/- 69.9 to 101.8 +/- 13.4 ng/ml/hr; (means +/- SE], enhanced ex vivo 6-keto PGF1 alpha production (from 1.38 +/- 0.05 to 3.76 +/- 0.18 ng/ml/hr), reduced plasma TXB2 concentration (from 88.1 +/- 13.9 to 38.8 +/- 5.9 pg/ml). There were no changes in plasma concentration of 6-keto PGF1 alpha. Dazoxiben did not improve total digital blood flow, capillary flow, AV shunt flow, or forearm blood flow at 28 degrees or 20 degrees. There was no subjective improvement in frequency or severity of Raynaud's attacks (assessed by patient diaries). It is concluded that dazoxiben is a potent and specific thromboxane synthetase inhibitor capable of altering arachidonic acid metabolism, but is of little or no benefit in the treatment of Raynaud's phenomenon.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Survival in chronic hepatitis B. An analysis of 379 patients.

Survival data from 379 patients with chronic hepatitis B were analyzed to determine life expectancy for the patient from the time of first contact. One hundred twenty-one patients had chronic persistent hepatitis, 128 had chronic active hepatitis, and 130 had chronic active hepatitis with cirrhosis. The frequency of symptoms (p less than 0.001), stigmata of chronic liver disease (p less than 0.001), and liver function test abnormalities (p less than 0.001) increased as the histologic features worsened, whereas the percentage of patients with circulating hepatitis B DNA polymerase declined (p less than 0.001). Women were uncommon in our series and had less severe disease than men (p less than 0.02). Fifty-one patients had died by the time of this analysis. The estimated 5-year survival rates were 97% for patients with chronic persistent hepatitis, 86% for those with chronic active hepatitis, and 55% for those with chronic active hepatitis with cirrhosis. The usual cause of death was liver failure and its sequelae. A multivariate analysis found age of 40 years or more, total bilirubin level of 1.5 mg/dL or more, ascites, and spider nevi to be factors that identified patients at a higher risk of death. The prognosis for patients with chronic hepatitis B is similar to that for patients with chronic hepatitis of other causes.

Adult↗
PubMed1983

Muscle electrolytes in malnutrition syndromes of children.

Muscle electrolyte composition has been studied in 10 infants with marasmus and eight children with kwashiorkor. The presence of altered muscle salt and water concentrations was confined in the latter nutritional syndrome. The marasmic infant, with equivalent or more severe nutritional wasting than the child with kwashiorkor, maintained a more normal muscle electrolyte concentration as indicated by a number of criteria. The pathophysiology of the altered muscle composition in kwashiorkor remains unclear; however, it appears to be more specific than due just to a depletion of available fat and muscle stores. Although possible endocrine mechanisms can be postulated to explain the change in muscle chemistry, the existing evidence is inadequate. Clearly, continuing research is warranted.

Adenosine Triphosphate↗
PubMed1982

[Response of the joint tissues to the presence of a foreign body implanted into the rabbit knee. A new model of experimental arthrosis].

The joint tissues (synovium, articular cartilage and bone), respond rapidly and consistently to the presence of a piece of polypropylene surgically implanted into the Rabbit knee joint. In the contact of a foreign body, a synovium proliferates in an attempt to isolate and exclude the intruder from the joint cavity. The articular cartilage degenerates at the sites of maximal pressure. Its superficial layer undergoes cell necrosis and fibrillation and is progressively destroyed in the process of mechanical grinding. At the sites of lower pressure, the chondrocytes proliferate and form the metabolically hyperactive clones which have increased capacity to incorporate tritiated thymidine and radioactive sulfate. The glycosaminoglycan content of articular cartilage, compared to the shamoperated control side, rapidly decreases after operation as suggested by a loss of metachromatic staining and lower per unit weight concentration of uronic acid and hexosamine. In addition to the above changes, the osteophytes quickly develop at the articular margins from the proliferating synovial tissue while underlying bone become thicker and eburnated. These foreign body induced changes in articular morphology and metabolism resemble closely those observed in osteoarthrosis. The present model therefore may prove useful in studying the latter condition.

Animals↗
PubMed1982

Complete nucleotide sequence and identification of membrane components of the histidine transport operon of S. typhimurium.

The nucleotide sequence of the entire histidine transport operon from Salmonella typhimurium has been determined and is shown to consist of four genes, hisJ, hisQ, hisM and hisP. This operon provides the only example of a binding protein-dependent transport system for which the total number of protein components is known. Determination of the amino acid compositions and sequences of these four transport proteins, together with analysis of various transport mutants, allows us to propose a molecular model for binding protein-dependent transport.

Amino Acid Sequence↗
PubMed1979

Effect of hemodialysis on glucose tolerance in children with chronic renal failure.

Five uremic (7.0 - 15.2 years), non-dialyzed children treated medically (group 1) had an intravenous glucose tolerance test (0.5 g/kg). Blood samples were obtained at frequent intervals and duplicate determinations of plasma glucose (glucose-oxidase method on Somogyi-Nelson protein-free filtrates), insulin and free fatty acids were performed. The same study was performed in eleven children (12.3 - 18.0 years) with chronic renal failure undergoing long-term hemodialysis (group 2), before and two hours after dialysis. Results were compared to a group (group 3) of eight healthy children (7.5 -- 17.5 years). In group 1 a "normal" insulin response was observed in the presence of hyperglycemia and the plasma glucose clearance was in the diabetic range. Twice weekly hemodialysis produced no beneficial acute effects on group 2, based on absolute glucose values or plasma glucose clearance rates, on groups as well as on individual basis; however, a clear hyperinsulinemia was present which was of even higher magnitude three and six months after the initial study. These results demonstrated that chronic hemodialysis had no beneficial acute effects on plasma glucose concentration or plasma glucose clearance rate. However, it may have obvious long term beneficial effects on glucose tolerance by enhancing pancreatic insulin release (to overcome peripheral insulin resistance) to such an extent as to maintain a normal carbohydrate tolerance.

Adolescent↗
PubMed1976

Propranolol effect on plasma glucose, free fatty acid, insulin, and growth hormone in Graves' disease.

A 3-hr glucose tolerance test was performed in 12 thyrotoxic patients before and after propranolol treatment for 30 days (120 mg/day). Plasma glucose, free fatty acid, insulin, and growth hormone levels were determined on each test and compared to each other and against nine clinically healthy volunteers. In eight thyrotoxic patients (subgroup A) an improvement in carbohydrate tolerance was observed after propranolol treatment, along with a fall in the previously elevated fasting FFA; no change in plasma insulin levels was observed. Plasma growth hormone levels were higher than normal both before and after propranolol; however, a 46% glucose-induced suppression was seen in both instances. In the other four patients (subgroup B) (who had had a marked and rapid weight loss) a deterioration of the previously normal glucosnificant changes in insulin levels. Elevated fasting plasma free fatty acids remained so despite propranolol treatment. Plasma growth hormone was higher than normal before and after propranolol; a late suppression (at 120 min) and no suppression at all were seen, respectively. After propranolol treatment, subgroup B had higher plasma free fatty acid than subgroup A in the fasting state and at 30 and 180 min. It is proposed that the improvement or deterioration in carbohydrate tolerance after propranolol treatment might be related to whether or not a satisfactory propranolol-induced lipolytic blockade is achieved, leading to a decrease in plasma free fatty acid levels, improved insulin sensitivity, and better peripheral glucose utilization. Therefore, a uniform dose of propranolol will not always be sufficient to obtain adequate lipolytic blockade, particularly if the thyrotoxic patient has had a marked and rapid weight loss.

Adolescent↗
PubMed1975

Energy metabolism and hormonal profile in children with edematous protein-calorie malnutrition.

Modifications in energy metabolism and endocrine homeostasis (plasma insulin and growth hormone values, glucose and free fatty acid levels, serum thyroxine and TSH, free thyroxine index, and urinary catecholamines) were investigated in eight children with edematous protein-calorie malnutrition. Caloric expenditure was low at admission and correlated linearly with increased caloric intake throughout the study. The hormonal changes at admission were characterized by a negligible insulin response to intravenous arginine or glucose and by markedly elevated growth hormone levels which were neither increased by arginine nor suppressed by intravenous glucose. Serum thyroxine values were low, but free thyroxine index and serum TSH levels were within normal limits. At admission to the study, 24-hour urinary excretion of dopamine and norepinephrine was relatively reduced in relation to the excretion of epinephrine. All these modifications were corrected at time of the recovery study. It is suggested that in edematous protein-calorie malnutrition, insulin acts as the primary regulator of peripheral fuel release and that the high, nonsuppressible growth hormone levels may form part of an important homeostatic mechanism to provide substrates for brain metabolism via lipolysis.

Anthropometry↗