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Biomedical subjects

F Gomez

Publications and source records attributed to F Gomez.

At least 127 records · Page 7Linked to original sources
PubMed1986

Receptors involved in helodermin action on rat pancreatic acini.

Helodermin is a new peptide isolated from the venom of Heloderma suspectum. Its effects on rat pancreatic acini were compared with those of secretin and vasoactive intestinal peptide (VIP). Four classes of receptors with decreasing affinity for secretin (S1, S2, S3, and S4) were first delineated. Occupancy of S1 and S2 by secretin was responsible for a biphasic adenosine 3',5'-cyclic monophosphate (cAMP) response. S3 was VIP preferring so that the VIP-induced increase in cAMP could be inhibited by VIP-(10-28). S2 and S3 allowed cAMP elevation, protein phosphorylation, weak secretory effects, and potentiation of cholecystokinin octapeptide (CCK-8) when occupied by secretin and VIP, respectively. A more efficient exocytosis was observed with secretin interacting with low-affinity receptors S4. Helodermin increased cAMP levels 14-fold, this increase being inhibited by VIP-(10-28). Low concentrations of helodermin stimulated amylase secretion twofold and potentiated secretion by CCK-8. High concentrations of helodermin stimulated secretion another 2.6-fold. Helodermin bound to the four secretin receptors with a weak selectivity. At low concentration, helodermin stimulated cAMP elevation, protein phosphorylation, amylase release, and potentiation of CCK-8 through S3, whereas at high concentration it stimulated secretion via S4.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Individualization of theophylline dosage in adults with bronchial asthma.

The influence of age on the disposition of theophylline was studied in 95 adult patients (nonsmokers) with bronchial asthma requiring oral theophylline therapy: 17 patients age less than or equal to 39 years, 50 patients age 40-59 years, and 28 patients greater than or equal to 60 years. A decrease was observed in total body clearance together with an increase in the elimination half-life of theophylline parallel to the advance in age of the patients. The apparent volume of distribution of theophylline was similar in the three groups of patients. According to the results obtained, recommendations are made regarding the dosage regimens of theophylline in elderly patients.

Adult↗
PubMed1986

Luteinizing hormone (LH) and prolactin-releasing pituitary tumor: possible malignant transformation of the LH cell line.

A pituitary tumor was diagnosed in a prepubertal 13-yr-old girl, who had elevated plasma LH (58 mIU/ml) and PRL (93 ng/ml) levels; decreased GH, ACTH, and FSH secretion; and diabetes insipidus. After surgery, plasma LH and PRL declined, but not to normal levels. Conventional external radiotherapy to the pituitary was immediately followed by a decrease in LH to prepubertal values (0.7 mIU/ml), while PRL levels became normal only after a long course of bromocriptine therapy. The pituitary tumor was composed of two distinct cell types: small polygonal cells, which were PRL positive by immunohistochemistry, and clusters of pleomorphic large frequently mitotic polynucleated cells, which were LH positive, some of them also being positive for the alpha-subunit or beta LH but not for beta FSH. Four years after surgery and radiotherapy, the patient deteriorated neurologically. Computed tomographic scan showed widespread frontal and periventricular tumor, which had the histological features of a poorly differentiated carcinoma. No PRL, LH, or alpha- or beta-subunits were detectable on immunocytochemistry. While the PRL-positive cells of the pituitary tumor displayed the histological and clinical features of PRL adenomas, the morphological characteristics of LH cells and the sharp decline of plasma LH levels after radiotherapy were suggestive of malignant transformation. In this context, the later brain tumor could have been the result of subependymal spread of the pituitary tumor after it lost its hormone-secreting capacity.

Adenoma↗
PubMed1986

Huntington's disease in Venezuela: neurologic features and functional decline.

We studied 65 Huntington's disease patients and 225 at-risk individuals over the past 4 years. The rate of decline of these untreated patients from Venezuela was similar to that seen in US patients who had received neuroleptic drugs. Chorea, oculomotor dysfunction, and dysdiadochokinesis were early symptoms; parkinsonian features and dystonia came later. Juvenile patients declined nearly twice as fast as adult-onset patients. No distinctive neurologic phenotypes were seen in children of two affected parents.

Adult↗
PubMed1985

Amygdala kindled seizure stage is related to altered benzodiazepine binding site density.

Benzodiazepine receptor binding was examined in rats at 3 stages of amygdaloid kindling (i.e., initial afterdischarge, Stage 3 and Stage 5) immediately or 24 hr after seizure. 3H-diazepam binding site density (Bmax) was significantly increased 24 hr after Stage 3 and Stage 5 kindled seizures in the hippocampus but not in the amygdala. There were no significant differences in the dissociation constants (KD) between kindled and control rats at any time point examined for either brain region. These results demonstrate that changes in benzodiazepine binding are observed with partial kindled seizures (i.e., Stage 3), indicating that generalized seizures are not prerequisite to increased benzodiazepine receptor site density.

Amygdala↗
PubMed1985

Effect of weight loss on glucose disposal in obese and obese diabetic patients.

The purpose of the study was to examine the effect of short-term weight loss on glucose disposal and lipid oxidation in obese patients. Twenty-six obese patients were divided into three groups according to their degree of glucose intolerance: normal glucose tolerance = Gp I; impaired glucose tolerance without diabetes = Gp II; diabetes = Gp III. The patients submitted to an hypocaloric, high-protein diet for 8 to 45 weeks. Respiratory exchange measurements were performed by means of continuous indirect calorimetry during a 100 g, 3 h oral glucose tolerance test (OGTT) before weight loss and were repeated at the end of the weight loss period, 3 to 8 weeks after the reintroduction of a balanced isocaloric diet. Glucose tolerance, which was decreased in Gps II and III, improved after weight loss. Glucose oxidation, which was decreased in Gps II and III showed improvement after weight reduction in both Gp II (30.9 +/- 2.3 after weight loss vs 24.2 +/- 2.0 g/3 h before, P less than 0.025) and in Gp III (33.1 +/- 1.6 vs 25.8 +/- 4.1, ns). In the diabetic group (Gp III), before weight loss, a decrease in nonoxidative glucose uptake was observed, which was probably due both to a decrease in glucose storage and to the inhibition of splanchnic glucose output. After weight loss, it increased significantly from 27.7 +/- 5.2 to 56.9 +/- 2.3 g/3 h (P less than 0.001). Postabsorptive plasma insulin levels decreased in all groups following weight reduction. When exaggerated the insulin response to the glucose load fell to normal values whereas the insulin response increased in the diabetic patients in whom it was initially blunted. Lipid oxidation rates, both preload and postload, were markedly elevated before weight loss in all three groups. They were substantially reduced after weight loss. This study shows that a weight loss of 10 to 33 kg in obese patients promoted an increase in the subnormal glucose oxidation rate in Gp II as well as an improvement of the low nonoxidative glucose uptake in the diabetic group, thus improving their glucose tolerance. There was a simultaneous reduction in lipid oxidation in both groups. Furthermore, the insulin response to the glucose load, whether elevated or decreased before weight loss, tended towards normalization after weight reduction.

Adult↗
PubMed1984

Pharmacokinetics of cefoxitin administered by i.v. infusion to patients with a pleural effusion.

The pharmacokinetics of cefoxitin was studied in 6 healthy volunteers and in 5 patients with a pleural effusion after administration of a single dose of 30 mg/kg i.v. infusion. The serum and pleural fluid concentrations of cefoxitin were determined microbiologically. The elimination half-life of the antibiotic from pleural fluid in all cases was 2-3 fold longer than from serum, which shows a difference between the kinetic elimination processes of the antibiotic from the two fluids. The slow elimination of cefoxitin from pleural fluid facilitates its accumulation in this compartment during a multiple dosage regimen.

Aged↗
PubMed1984

A highly sensitive radioimmunoassay for human growth hormone using a monoclonal antibody.

Biozzi-strain mice were immunized with a highly purified preparation of 20K variant of hGH. Spleen-cells were fused with SP2/0Ag14 myeloma cells. Clone productions were screened for specificity toward 20K and 22K hGH and for the affinity constant of antibody-antigen reaction. For the selected monoclonal antibody, Ka was 1.02.10(11) L/M using 22K hGH as both tracer and reference preparation. No cross reactivity was found with PRL and other pituitary hormones; hPL reactivity was 0.002 percent that of hGH. According to these antibody characteristics, a highly sensitive RIA system was developed and used for specific GH measurement in human serum. Using logit-log co-ordinates, the slope of the standard curve was -1.099 and the minimum detected dose was 0.5 uIU/ml. Excellent correlation (r = 0.9575) was found between assay data in this system and those of a conventional RIA method using specific polyclonal rabbit antiserum. The International Reference preparation (66/217) could adequately be used to calibrate the monoclonal antibody system since the in house internal 22K GH standard and international one were equally well recognized by the monoclonal antibody.

Animals↗
PubMed1984

[Acute suppurative mediastinitis in heart surgery performed under extracorporeal circulation].

The incidence of acute suppurative mediastinitis after open heart cardiac surgery in a 5 year retrospective study was found to be 1.56%. The commonest causal agent was the DNAse + coagulase + staphylococcus (68.8%). All cases were treated with bactericidal antibiotics and local measures (dosed chest irrigation-drainage in 1 or 2 stages). Adult men, early and/or late reoperation, immediate postoperative complications (cardiovascular collapse, haemorrhage) were positive risk factors. On the other hand, the type of underlying cardiac disease, the duration of surgery and bypass time, emergency surgery, and protocols of prophylactic antibiotic therapy did not seem to influence this risk. No sources of exogenous contamination, no notions of epidemics or periodicity were discovered in this study. The clinical course may be complicated, especially by renal failure. Thirty-two of the 109 patients studied died. However, the prognosis has improved in the last 5 years in relation to technical advances in intensive care and, above all, to adoption of 1 stage dosed chest irrigation-drainage: the mortality rate has fallen from 37.2% in the first period to 20% more recently. When a cure is obtained, it is complete and there are no sequellae. Nevertheless, irrespective of the adoption of draconian measures of asepsis and protocols of prophylactic antibiotic therapy, the risk of acute postoperative mediastinitis persists. This suggests that the efficacy of the patient's local (and general) anti-infective immunity defenses may vary in the presence of constant mediastinal bacterial contamination despite aleatory preventive measures, due to the remenance of the skin flora.

Acute Disease↗
PubMed1984

Comparative evaluation of mitral valve repair and replacement with Starr, Björk, and porcine valve prostheses.

Four hundred consecutive patients with isolated mitral valve disease who were operated on between 1974 and 1977 underwent long-term evaluation. In this group there were 100 valve repairs, 100 porcine valves, 100 Starr valves, and 100 Björk valves. There were no significant differences in the preoperative clinical conditions of the patients in the four groups. Cumulative follow-up was 2058 patient-years. We concluded from the data that mitral valve repair was associated with fewer valve-related complications than valve replacement. Thromboembolism was the most significant parameter with respect to determining long-term results of the use of the porcine, Starr, and Björk valve prostheses.

Actuarial Analysis↗
PubMed1983

[Diabetes mellitus: the role of metabolic control in the prevention of complications].

Recent studies have cast doubt on the idea, generally agreed but not unequivocally proven, that optimal control of diabetes could delay or prevent the development of late microangiopathic complications of the disease. In particular, a perfect equilibration of glycemic values could, in certain cases, deteriorate, rather than improve, the situation (pre-proliferative retinopathy). Through a review of literature the authors try to answer the following questions: is diabetic microangiopathy due to hereditary factors? Can the treatment of diabetes influence the appearance of late "triopathic" complications? If yes, could an optimal metabolic control result in a stop or a regression of these lesions? Based on the available data, the authors reach the conclusion that yes, it is worthwhile to treat correctly diabetes mellitus and, if possible, a perfect glycemic control should be sought. There are only few and well determined exceptions to this rule. In insulin dependent diabetics a perfect control can presently be obtained by means of conventional intensified insulin treatment (multiple injections) or of continuous subcutaneous insulin infusion (insulin pump) for variable periods of time.

Animals↗
PubMed1983

Purification of the 22000- and 20000-mol.wt. forms of human somatotropin and characterization of their binding to liver and mammary binding sites.

Quantitative data concerning the binding of 22000-mol.wt. human somatotropin and its 20000-mol.wt. variant are described using pregnant-rabbit liver and mammary-gland receptors. The purification and the complete chemical characterization of both human somatotropin and its 20000-mol.wt. variant is also presented. Contamination of the 20000-mol.wt.-variant preparation by 22000-mol.wt. hormone was found to be 0.5% by weight as measured in radioimmunoassay using monoclonal antibody. Labelling of human somatotropin and its 20000-mol.wt. variant using the Iodogen method is described as well as the characterization of the binding to pregnant-rabbit liver and mammary-gland receptor preparations. The maximum binding capacity of the 125I-labelled human somatotropin was between 50 and 60% to liver particulate receptor, whereas that of the 20000-mol.wt. variant was 30%. The specificity of binding of both forms to rabbit hepatic and mammary-gland receptor was found to be similar for both proteins in the same system. The affinity constants and capacity were respectively 0.7 X 10(10)M-1 and 815 fmol/mg of protein for human somatotropin and 0.6 X 10(10)M-1 and 1.250 fmol/mg of protein for the 20000-mol.wt. variant. These data suggest that both proteins behave as partial agonists to the receptors studied.

Animals↗
PubMed1983

Surgical correction of the failed orchiopexy.

The reasons for failure of orchiopexy were investigated by reviewing the records of 350 boys with undescended testis. There were 36 boys (10 per cent) who had experienced failure of an initial surgical procedure. We found that the standard surgical techniques of local inguinal dissection, high ligation of a patent processus vaginalis, extensive retroperitoneal mobilization of the spermatic vessels and vas deferens, and/or creation of a dartos pouch were sufficient to correct these failures. Retroperitoneal dissections were required to correct the undescended testes in 58 per cent of the boys. Only 37 per cent of the boys could be treated satisfactorily by localized inguinal dissection. It appears that standard surgical techniques, especially aggressive retroperitoneal dissection, are adequate to correct even troublesome cases of undescended testis.

Adolescent↗
PubMed1983

Cecoureterocele: morphology and clinical correlations.

A unique necropsy specimen of a cecoureterocele, together with the bladder and urethra in a female newborn, was studied to determine the structure of the ureterocele and the accompanying vesicourethral sphincter. The ureterocele within the bladder base and the entire urethra were examined macroscopically and microscopically in serial sections. The ureterocele and its cecal extension were amuscular. The bladder neck, and the involuntary and voluntary sphincters were attenuated or devoid of muscle in the quadrant beneath the ureterocele and its cecal extension. These findings were correlated with the clinical features of 2 living patients with comparable ureteroceles who had urinary incontinence following surgical excision of the ureteroceles.

Child, Preschool↗