The relationship of ligand receptor mobility to internalization of polypeptide hormones and growth factors.

Polypeptide hormones and growth factors bind to cell surface receptors and are internalized by receptor-mediated endocytosis. Both [125I]insulin and [125I]epidermal growth factor (EGF) are internalized to a much greater extent than [125I]glucagon in freshly isolated rat hepatocytes. All three ligands bind initially and preferentially to the microvillous surface of the hepatocyte, but only [125I]insulin and [125I]EGF undergo significant redistribution to the nonvillous surface of the cell.

A comparative pathological study of three strains of Trypanosoma cruzi in an experimental model.

Trypanosoma cruzi, the etiological agent of Chagas' disease, shows a wide variation in its biological behaviour depending on the geographical distribution of different strains. Moreover, some strains can show variations with the course of time. We have studied the tissular tropism of three strains of T.

The application of the statistical study in the morphometric characterization of a Colombian strain of Trypanosoma cruzi.

After morphological and histopathological characterization, the Cali strain of T. cruzi isolated from a patient in Cali (Colombia), was also submitted to a morphometrical characterization. For this we estimated 16 cellular parameters in 30 samples of each evolutive form of T.

Tumor markers in pancreatic cancer: a comparative clinical study between CEA, CA 19-9 and CA 50.

Seventy-eight patients were evaluated to ascertain the usefulness of markers CA 19-9 and CA 50 in diagnosing pancreatic cancer, using a less specific marker (CEA) as reference. Three groups were considered: a) 36 controls; b) 22 patients with benign obstructive jaundice; c) 20 patients with pancreatic cancer. Preoperative blood samples were obtained to ascertain CEA (E.

Acute chagasic cardiopathy produced by a strain of Trypanosoma cruzi (type I) in an experimental model.

We have carried out a study of the tissular tropism of the strain Y of T. cruzi considering that the different strains of T. cruzi show a great instability in their pathogenic properties with the aim of proving that the classifications of his parasite based in its tissular tropism are not reliable given that these characteristics are subject to change as can be seen by comparing our results with those of other authors.

Magnetic resonance imaging and angiography of the brain in embolic left atrial myxoma.

A case of left atrial myxoma presenting exclusively with neurological symptoms, studied with magnetic resonance imaging (MRI) combined with cerebral angiography and computed tomography (CT) is reported. Typical angiographic findings suggested the diagnosis of myxoma. MRI showed multiple ischemic lesions disseminated throughout the entire brain, some of which had been clinically asymptomatic.

Effect of pinealectomy and of diabetes on liver insulin and glucagon receptor concentrations in the rat.

The studies described in this paper were undertaken to characterize the circulating and hepatic insulin and glucagon receptor concentrations of control (C), diabetic (Db), and pinealectomized-diabetic (Pn + Db) rats. Compared with C rats, an increase in plasma glucose and glucagon levels and a reduction in circulating insulin concentrations in Db animals was observed; these differences were greater in Pn + Db rats. In liver membranes, insulin binding was lower in Db and in Pn + Db than in C rats, and glucagon binding was greater in Db and in Pn + Db than in C rats.

Effect of pinealectomy on liver insulin and glucagon receptor concentrations in the rat.

The studies described here were undertaken to characterize the hepatic insulin and glucagon receptors of control (C), pinealectomized (Pn), and melatonin-treated pinealectomized (Pn + Mel) rats. Compared with C rats, an increase in plasma glucose and glucagon levels and a reduction in circulating concentrations of insulin in Pn animals were observed. Melatonin treatment of Pn rats reverses all three parameters toward the normal values.

Intestinal angiodysplasia: retrospective study of 18 cases.

Eighteen patients operated on for intestinal angiodysplasia are reported. Visceral angiography was the diagnostic procedure of choice, providing evidence in most cases of lesions in the right colon. Right hemicolectomy was the surgical treatment normally provided.

Operative choledochoscopy in biliary surgery.

Forty-six patients submitted to operative choledochoscopy during biliary surgery are presented. Forty-two had benign diseases, principally calculi (38 cases), with only four patients presenting with malignant neoplasms. Our results bear out the effectiveness of operative choledochoscopy as a complement to cholangiography and conventional exploration of the bile duct, in significantly reducing the number of retained stones found, and in aiding other surgical procedures in the biliary tract.

Ligand-induced changes in insulin receptors in cell surface and Golgi fractions of fetal rat liver.

The studies described in this paper were undertaken to characterize the insulin receptors present in the plasma membranes and Golgi fractions of fetal rat liver and to determine their subcellular distribution after the administration of exogenous insulin. Purification patterns of both types of liver membranes from fetal and adult rats were similar, as verified by morphological and biochemical approaches. In both groups insulin binding was significantly greater in plasma membranes than in Golgi fractions.

Obstruction of the bile duct by a papillary adenoma of the gallbladder.

A case of papillary adenoma of the gallbladder unassociated with cholelithiasis and showing detachment of part of the growth with obstruction of the common bile duct is described. One the basis of a search of the literature, it would appear that this is the first time such a case has been reported. The bibliography is discussed and a distinction drawn between this kind of adenoma and other benign tumors of the gallbladder.

Type Ia tricuspid atresia with extensive coronary artery abnormalities in a living 22 year old woman.

Type Ia tricuspid atresia, with extensive coronary artery abnormalities, is identified in the oldest living patient with this condition, a 22 year old woman. Clinical characteristics include severe cyanosis, effort dyspnea, myocardial infarction in the past and persistent angina pectoris. "Ideal" pulmonary flow and adequate left ventricular function, despite an akinetic apical segment, are substantive factors for this exceptional longevity.

Characterization of glucagon receptors in Golgi fractions of fetal rat liver.

The present study was designed to determine if Golgi fractions from fetal rat liver contain glucagon receptors and to characterize the properties of such receptors. Purification patterns of liver plasma membranes and Golgi fractions from fetal and adult rats were similar, as verified by morphological and biochemical approaches. Glucagon binding was greater in plasma membranes of adult than fetal rats, while in Golgi fractions glucagon binding was similar in both groups.

Characterization of glucagon receptors in liver membranes and isolated hepatocytes during rat ontogenic development.

We studied the functional properties of hepatic glucagon receptors during rat development. Glucagon binding to liver membranes and isolated hepatocytes was significantly less in foetuses and weaning rats than in adult animals, reflecting changes in the number of receptors rather than any change in receptor affinity for the hormone. After correcting for the smaller surface area of foetal hepatocytes, glucagon receptor concentrations were still lower in foetuses than in adult rats.

[Conventional and analytic morphometry using the IBAS-1 computer in experimental Trypanosoma b. brucei infection].

A comparative morphometrical study of the experimental infection with T. b. brucei was realized using the conventional method and the IBAS-1 analytic computer.

Influence of the conjoint administration of insulin and glucagon upon hepatic regeneration.

In noneviscerated rats, the influence of the conjoint administration of insulin and glucagon in the regenerative response triggered by 70 per cent hepatectomy using the incorporation of tritiated thymidine by nuclear deoxyribonucleic acid as a parameter has been demonstrated. The response was earlier and more intense in relation to animals not hormonally stimulated and stimulated only with glucagon (previously reported by us). Such a response has been comparatively greater both in the nonparenchymal cells and in the hepatocytes, especially in the latter, which are the main cause of the early peak of thymidine incorporation in the periportal zones indicating a greater regenerative activity than in the intermediate and centrolobular zones.

Diagnostic significance of some urinary enzymes for detecting acute rejection crises in renal-transplant recipients: alanine aminopeptidase, alkaline phosphatase, gamma-glutamyltransferase, N-acetyl-beta-D-glucosaminidase, and lysozyme.

We compared the diagnostic validity of five urinary enzymes--alanine aminopeptidase (EC 3.4.11.

Popliteal artery entrapment syndrome.

Three cases of popliteal artery entrapment syndrome, one of them bilateral, are presented with a review of the literature, with special reference to the embryological development of the popliteal space and the diagnostic and therapeutic problems presented by this syndrome.

Glucagon-like peptide-1 does not have a role in hepatic carbohydrate metabolism.

Glucagon-like peptide-1 does not have specific, high-affinity receptors on rat liver membranes, does not displace glucagon from glucagon receptors on these membranes and does not stimulate the production of cyclic AMP by isolated rat hepatocytes. In the presence of glucagon, high concentrations of glucagon-like peptide-1 do not significantly alter the production of cyclic AMP. Thus, glucagon-like peptide-1 appears unlikely to have a direct action on hepatic carbohydrate metabolism.

Diagnostic significance of urinary enzymes in detecting acute rejection crises in renal transplant recipients depending on expression of results illustrated through the example of alanine aminopeptidase.

In 82 renal transplant recipients we measured the excretion of urinary alanine aminopeptidase (EC 3.4.11.