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Biomedical subjects

A Escobar

Publications and source records attributed to A Escobar.

At least 55 records · Page 3Linked to original sources
PubMed1992

Effect of ascorbate in the reduction of transferrin-associated iron in endocytic vesicles.

Externally added ascorbate or NADH effectively reduced ferricyanide and promoted the exit of Fe3+ originated from acid-destabilized transferrin contained inside endocytic vesicles. The effect of ascorbate was mediated by an ascorbate uptake system, and the effect of NADH was mediated by the membrane-associated oxidoreductase. At physiological concentrations of both ascorbate and NADH, the ascorbate transport and the NADH-oxidoreductase system were additive as measured by the rate of reduction of ferricyanide and by the mobilization of transferrin-associated iron. The results indicate that Fe3+ reduction may occur by a non-enzymatic reaction with ascorbate transported into the vesicle lumen. The ascorbate-mediated reduction of iron derived from transferrin occurring in the endosome could play a major role in cellular iron uptake.

Animals↗
PubMed1990

Endocytic vesicles contain a calmodulin-activated Ca2+ pump that mediates the inhibition of acidification by calcium.

Endocytic vesicles isolated from rabbit reticulocytes contained an intrinsic Ca2(+)-pump activity that was dependent on ATP, activated by calmodulin and inhibited by vanadate. 45Ca2+ uptake and acidification studies indicated that acidification of the endocytic vesicles inversely correlated with the Ca2(+)-pump activity. Acidification was inhibited by externally added Ca2+ and calmodulin and activated by vanadate and EGTA. It is suggested that intravesicular Ca2+ can act as a modulator of endocytic vesicle acidification.

Animals↗
PubMed1990

Multiple brain abscesses from isolated cerebral mucormycosis.

A report is presented of a patient with cerebral mucormycosis without rhinosinusal or systemic evidence of the disease. The predisposing condition was drug-induced immunosuppression. Computed tomography (CT) showed focal areas of abnormal enhancement which correlated with necropsy findings of localised parenchymal brain damage; this represented encapsulated brain abscesses, a rare form of presentation of cerebral mucormycosis.

Adult↗
PubMed1990

Identification of Entamoeba histolytica antigens recognized by IgA class human antibodies in sera and colostra of puerperal women using immunoblotting techniques.

Immunodetection of total antigens of Entamoeba histolytica trophozoites transferred to nitrocellulose paper was realized with IgA antibodies present in colostra and sera samples of 28 puerperal women and in 24 sera samples of patients with a diagnosis of amebic hepatic abscess. The most frequently recognized antigens by colostra antibodies were those which correspond to 1290, 82.79, 52.14, 40.91, 37.75, 35.08, 33.52, 28.53, 27.53 and 25.32 KDa of molecular weight, in the case of puerperal sera those of 82.79, 52.14, 40.91, 37.75, 35.08, 33.52, 28.53, 27.53, and 25.32 KDa, whereas the sera of patients with amebic hepatic abscess those of molecular weight of 719, 118.45, 88.45, 69.45, 55.26, 52.14, 49.38, 42.72, 36.81, 35.08, 33.52, 25.32, 23.82, 23.47, 20.52 and 20.03 KDa. The putative adhesins were recognized infrequently by Iga of puerperal colostra and sera while the IgA of sera of patients with amebic hepatic abscess recognized those of 118.45 KDa (112 KDa in other studies) in 83.33% of the cases.

Animals↗
PubMed1989

Treatment of diet-resistant polygenic hypercholesterolaemic patients with a new nicotinate derivative; in vivo and in vitro low density lipoprotein metabolic studies.

Six patients (four women and two men) with mild to moderate hypercholesterolemia, but with no clinical evidence of the disease being monogenic familial hypercholesterolaemia and who, over the previous 3 months on a rigidly controlled hypolipidaemic diet therapy, showed no reduction in plasma cholesterol levels, were recruited into a study to assess the metabolic effects of Pirozadil, a new nicotinic acid derivative. After a 3 month treatment period, a significant reduction in plasma cholesterol from 299.8 +/- 31.2 mg/dl (mean +/- SD) to 256.8 +/- 18.1 mg/dl (P less than 0.02) and Low Density Lipoprotein (LDL) cholesterol from 211.7 +/- 44.9 mg/dl to 168.8 +/- 19.0 mg/dl (P less than 0.05) was observed. Although there was a trend toward decreased plasma and Very Low Density Lipoprotein (VLDL) triglyceride, the differences did not reach statistical significant. High Density Lipoprotein (HDL) cholesterol was unchanged. The drug was well tolerated with no side effects noted. To assess the mode of action, autologous125I-labelled LDL was injected and apoprotein B (apo B) kinetic parameters were measured; production rate (PR) and fractional catabolic rate (FCR). An in vitro measurement of the in vivo catabolism (LDL-apo B receptor activity in freshly isolated lymphocytes) was also measured pre- and post-treatment. The pharmacological intervention resulted in a significant decrease of 19.9% in PR from 10.5 +/- 1.81 mg/kg/d to 8.41 +/- 1.13 mg/kg/d (P less than 0.05) while the FCR remained relatively unchanged (0.260 +/- 0.042 vs 0.248 +/- 0.040 pools/d) as did the LDL receptor activity (78.2 +/- 20.9 vs 69.3 +/- 21.4 ng LDL/mg cell protein/hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoproteins B↗
PubMed1989

Chorea-acanthocytosis: report of a family and neuropathological study of two cases.

We report three siblings, offspring of normal consanguineous parents, with a progressive neurological illness that began in midlife and was characterized primarily by chorea and leading to death in the fourth decade. The proband had erythrocyte acanthocytosis with normal serum beta-lipoprotein. Biopsy of left gastrocnemius muscle showed neurogenic muscular atrophy. There was a decrease in the numbers of large myelinated axons of the sural nerve. Postmortem examination of two cases showed marked atrophy, neuronal loss and gliosis of the caudate nucleus and putamen. Autosomal recessive inheritance is likely in this family.

Acanthocytes↗
PubMed1989

Occlusion of the middle cerebral artery due to cysticercotic angiitis.

Three patients with cysticercosis developed a cerebral infarct secondary to the occlusion of the middle cerebral artery or its major branches. Histopathologic examination revealed a large subarachnoid cysticercus surrounding the occluded arteries in two patients and diffuse thickening of the leptomeninges in one. Blood vessels around the parasite showed inflammatory changes that caused either occlusive endarteritis or thrombosis due to disruption of the endothelium. Cysticercosis should be considered as a cause of occlusion of the major intracranial vessels, particularly in young patients living in areas where this disease is endemic.

Adult↗
PubMed1986

The pharmacodynamic response of the basal skin potential to quinidine gluconate.

The basal skin potential (BSP) was explored as an indirect means of continuously monitoring the cardiac response of quinidine gluconate. A method was developed to follow the BSP using a high impedance, recording polygraph and nonpolarizing calomel electrodes. Intravenous administration of quinidine gluconate caused time dependent changes in the BSP. Further studies showed that blood levels during the elimination phase and the QT interval of the electrocardiogram (ECG) over their entire time period were highly correlated with the BSP. Optimal correlation with the QT interval occurred when the BSP curve was shifted to earlier times by approximately 10 minutes, reflecting possible differences in the accessibility or mechanism of the respective pharmacologic compartments. Further application of the BSP for pharmacodynamic monitoring will require electrode refinements and an increased understanding of its mechanism of action.

Animals↗
PubMed1984

Determination of heparin activity by a new laser nephelometric method and comparison to the USP method.

A new method for the determination of heparin activity in solutions has been developed, based on the increase in light scattering observed during the clotting of plasma. The recalcification clotting time (RCT) of sheep plasma is measured in the presence of heparin, using a laser nephelometer. The activity of heparin in the sample is determined from a standard curve of the logarithm of RCT versus heparin activity. The results indicate that this method is simpler, faster, and more reproducible than the current USP grading method.

Animals↗
PubMed1983

Wernicke's encephalopathy. A case report with neurophysiologic and CT-scan studies.

A case of Wernicke's encephalopathy with ataxia, confusion, memory loss, partial seizures of complex behavior and hypothermia, subsequent to thiamine depletion due to chronic malnourishment and triggered by an episode of acute vomiting and diarrhea, is reported, Computerized tomography (CT-scan) depicted small bilateral lesions in areas adjacent to the walls of the third ventricle, common location of the lesions seen in autopsy material of Wernicke's encephalopathy. Early diagnosis and treatment with vitamin B complex supplemented with intensive mnemonic and cognitive therapy led to complete recovery in a ten day period.

Adolescent↗
PubMed1982

Enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to cysticerci of Taenia solium.

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to cysticerci of Taenia solium has been developed that employs a pork muscle antigen control for the cysticercus test antigen, somewhat improving the serological distinction between infected and uninfected subjects. Serum antibody to cysticercus was detected in 79% of classical neurocysticercosis patients from Mexico, and in 61% of a group of cysticercosis patients with an unusually rapid invasion of the central nervous system in an endemic focus of disease in Irian Jaya. Antibody was absent in a group of healthy American laboratory personnel, and in residents of a non-endemic region of Papua New Guinea. Additional test on sera from patients with other parasitic diseases showed that cross-reactivity may occur in some patients with schistosomiasis, echinococcosis, and possibly angiostrongyliasis; however, these parasites are not known to cause human infection in Irian Jaya.

Animals↗