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Biomedical subjects

A Varela

Publications and source records attributed to A Varela.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Diabetes prevalence in a school population of Avellaneda, Argentina].

An interview system was used to survey 56,199 students in Avellaneda between the ages of 3 and 20 years, representing 60.6% of the population of that age group in the census. The study covered 178 of the 201 pre-schools, grade schools, high schools and special schools in the area. Thirty three diabetic children were identified (18 girls, 15 boys), with a mean of 12.5 years of age. This represents a prevalence of diabetes in the school age population of 0.45/1000 in the 3-12 year old group, 1.25/1000 in the 13-20 year old group, with 0.59/1000 for the total of children surveyed. (93.82 of ascertainement, 95% CI 0.34 to 0.42/1000). Similar figures have resulted from studies in developed countries. The most frequent initial symptoms were the typical ones, with only 15% showing acidosis or diabetic coma as the initiation of the illness. Viral infections and stress appeared to be related to the onset of the disease. Diabetes was in the family history of 48.5% of the diabetic children, and 24.5% of the non-diabetics. The most common diabetic relative was the paternal grandfather. The maternal side showed a higher number of diabetic relatives with preponderance of males. No socio-economic differences were found between diabetics and non-diabetics.

Adolescent↗
PubMed1992

Surgical treatment of stage III non-small cell bronchogenic carcinoma involving the chest wall.

Thirty-five patients who had undergone surgery for non-small cell bronchogenic carcinoma with isolated involvement of the chest wall were reviewed. The diagnosis was preoperatively suspected in 80% of cases. En-bloc resection of the invaded chest wall was performed in 25 cases and parietal pleurectomy in ten in which the pleura was easily dissectable from the costal plane. Of the eight patients with major complications in the early postoperative period, six, including the two who died perioperatively, had undergone en-block resection. The 5-year actuarial survival rate was 22% overall and 36% in the patients without lymph node involvement. No significant relationship between survival and type of operation or degree of chest wall invasion was found. Isolated involvement of the chest wall by non-small cell bronchogenic carcinoma does not necessarily contraindicate surgery with curative intent. Parietal pleurectomy is valid in selected cases. Long-term survival depends basically on node involvement.

Actuarial Analysis↗
PubMed1992

Effects of methyl palmoxirate on hypoxic rat atria.

Isolated rat atria in hypoxia released lactate into the bathing medium and underwent a decline of the contraction frequency which, in some cases led to a complete cessation of the pacemaker activity. A pronounced fall in the peak developed tension and a rise in the resting tension also appeared. The atria from 24 h fasted rats, which oxidize faster their reserve lipids than those from fed rats, exhibited greater functional disturbances during hypoxia, a lower lactate output and a smaller recovery of peak tension upon reoxygenation. Methyl palmoxirate, which is a selective inhibitor of carnitine palmitoyltransferase I, attenuated the decline of the beating rate and the rise of the resting tension in both groups of rats and the incidence of atrial arrest in the fasted rat group. The fall in the peak tension, lactate output and recovery upon reoxygenation were not altered by the inhibitor. These data indicate that methyl palmoxirate alleviates some of the hypoxic functional derangements. Hence, it may be inferred that inhibiting the oxidation of the fatty acid derived from the endogenous triacylglycerol is beneficial during oxygen-limited conditions and that these effects could not be ascribed to changes in the glycolytic flux.

Anaerobiosis↗
PubMed1992

Effects of methylpalmoxirate on isolated rat atria.

The aim of the investigation was to assess whether endogenous triacylglycerol contributes to the maintenance of the contractile and pacemaker activities of the isolated atria from fed and fasted rats. To attain this information, the atria were treated with methylpalmoxirate which is a potent inhibitor of carnitine palmitoyltransferase I. In the presence of glucose, methylpalmoxirate abolished the lipolysis without affecting peak developed tension or the atrial rate. When exposed to a substrate-free medium containing 2-deoxyglucose, the atria displayed a progressive fall of the pacemaker frequency, a pronounced decay of contractile strength and the appearance of contracture. These derangements appeared faster in the atria from fed rats coinciding with a smaller triacylglycerol mobilization. Methylpalmoxirate suppressed triacylglycerol breakdown, increased the contracture strength, accelerated the fall of the atrial rate and in a significant number of fasted atria it led to a complete cessation of the spontaneous contractions. The decline of the peak tension was not altered by the inhibitor, probably because the contractile strength was too weak in the glucose-free medium, so that additional negative inotropic effects were not detectable. These data suggest that exogenous glucose in addition to that derived from glycogen meet the atrial energy requirements when the fatty acid oxidation is hindered. The deleterious effects exerted by methylpalmoxirate after the glucose metabolism was eliminated indicate that endogenous triacylglycerol supports, at least partly, the atrial functions.

Animals↗
PubMed1992

Surgical treatment of ventricular tachycardia by balloon electric shock ablation. Potential effects on the mitral valve apparatus.

We have previously described a new surgical technique for control of arrhythmogenic foci in patients with recurrent ventricular tachycardia that we call balloon electric shock ablation. With this method sequential shocks are delivered to a grid of electrodes on a balloon that can be introduced across the mitral valve into the intact ventricle. A series of experiments was undertaken to investigate possible deleterious effects of balloon electric shock ablation when shocks are delivered directly to the mitral valve apparatus. In six animals shocks totaling 1200 joules were given through a closely spaced electrode grid applied to the area of the mitral valve. Nine to 12 weeks later, left ventricular and mitral valve function were assessed. Balloon electric shock ablation in the basilar portion of the ventricle was associated with decreased myocardial performance, as evidenced by ejection phase indices. In five of six animals balloon ablation led to minor thickening of the valve leaflets and chordal attachments plus necrosis of adjacent myocardium, including papillary muscles. In these animals there was no significant dysfunction of the valve observed. In the remaining animal, however, ablation was centered on the posterior papillary muscle and resulted not only in necrosis of the base of the papillary muscle but also in full-thickness scarring and thinning of the adjacent left ventricular wall. In this dog, mitral regurgitation was seen on long-term follow-up. We conclude that when balloon electric shock ablation is used to destroy a localized area of myocardium in the basilar portion of the intact ventricle, the procedure results in decreased myocardial performance. When shocks were directly applied to the mitral valve apparatus in five of six animals, ablation did not result in significant negative effects on the structure and function of the valve. In the sixth dog, however, shock delivery resulted in transmural necrosis and thinning at the site of papillary muscle insertion and was associated with severe mitral regurgitation with volume loading. Therefore caution should be used when considering clinical application of this technique if the area to be ablated is in the basal portion of the heart.

Animals↗
PubMed1991

Tracheal agenesis: an unresolved problem.

A case of tracheal agenesis diagnosed at birth is discussed in which surgical correction was attempted. Both main bronchi were divided and anastomosis of the main right bronchus to the larynx was attempted, after intrapericardial release of the right lung and severing of the lower pulmonary ligament: bronchoplastic reconstruction of the trachea was impossible. We think that tracheal agenesis, a rare cause of respiratory distress in the newborn, has no suitable therapy today. It is justified to attempt surgical correction if any promising device is at hand or if any doubt exists that an uncorrectable situation is present.

Humans↗
PubMed1990

Use of Gianturco self-expandable stents in the tracheobronchial tree.

Gianturco self-expandable stents were used successfully in the management of 5 patients with tracheobronchial pathology. Placement was performed under endoscopic and fluoroscopic guidance. None of the patients has experienced complications secondary to the stent placement, and in all of them the clinical problems resolved satisfactorily. Longer follow-up is required to determine the place of tracheobronchial stenting in patients with respiratory compromise.

Aged↗
PubMed1989

The effects of 4-pentenoic and pentanoic acid on the hypoxic rat atria.

When exposed to hypoxia, the isolated rat atria released lactate into the bathing medium and underwent a rise in resting tension and a decline of the contractions frequency. In some of them, it also occurred a complete cessation of the pacemaker activity. Atria from 24-h fasted rats, when compared to those from fed ones, exhibited a lower lactate output, a higher rise in resting tension, a faster decay of the contraction frequency and an increased occurrence of atrial arrest. In both the fed and fasted rats atria, some triacylglycerol lipolysis remained throughout the hypoxic incubation. Addition of 2 mM 4-pentenoic acid abolished the lipolytic activity and reduced lactate output in both groups of atria. In the fed rats atria it also accelerated the decrease of the pacemaker frequency. Pentanoic acid reduced lactate output in both groups of atria and in those from fed rats it did not alter lipolysis but increased the rise in resting tension, the decline of the pacemaker frequency and the occurrence of atrial arrest. Present data indicate that although 4-pentenoic acid inhibits fatty acid oxidation and endogenous lipolysis, it was not able to reduce the noxious effects of hypoxia. Since the effects of 4-pentenoic acid were rather similar to those of fasting and pentanoic acid, they might be ascribed to the accumulation of its own oxidative metabolites which could be detrimental for the hypoxic atria.

Animals↗
PubMed1989

Malignant B cell immunoblastic lymphoma expressing CD30 antigen in the terminal phase of a multiple myeloma.

An acute terminal phase of a Bence Jones kappa plasma cell myeloma developed 22 months after chemotherapy is presented. The patient's symptoms were fever, cytopenias, adenomegalies and hepatomegaly. A lymph node biopsy showed an immunoblastic polymorphic kappa B cell lymphoma, expressing CD30 antigen. After new polychemotherapy the patient died because of bleeding and infection. Autopsy revealed a decrease in the tumour with defective immunophenotype. The few reported cases have been reviewed with emphasis on clinical aspects, prognosis and morphology, The significance of CD30 positivity (activation marker) in a high-grade lymphoma is discussed.

Aged↗
PubMed1988

The effects of 4-pentenoic and pentanoic acids on the isolated rat atria.

The peak developed tension and the pacemaker frequency of the isolated atria from fed and fasted rats, declined progressively during the incubation in a glucose-free medium containing 2-deoxyglucose. The atria from fed rats exhibited a faster decline than those from fasted rats, which was associated to a slower triacylglycerol lipolysis. 4-Pentenoic acid inhibited the lipolysis of both groups of atria but did not alter the atrial contractile performance. However, it enhanced the decline of the pacemaker frequency in the atria from fasted rats whereas, in contrast, it alleviated the decline in the fed atria. n-Pentanoic acid ameliorated the impairment of the contractile and pacemaker activities in both groups of atria, without affecting the lipolysis. It was concluded that, since the inhibition of the intramyocardial lipolysis did not correlate with changes of the atrial functions, 4-pentenoic acid was not appropriate to assess about the contribution of endogenous triacylglycerol to the maintenance of the atrial contractile and pacemaker activities.

Animals↗
PubMed1988

Endogenous triacylglycerol utilization by the isolated rat atria.

The isolated atria from 24 h fasted rats, either in the presence of glucose or in a substrate-free medium containing 2-deoxyglucose, mobilized the endogenous triacylglycerol (TG) to a greater extent than those from fed rats. The TG of the fasted atria had almost disappeared at the end of the 90 min incubation in the substrate-free plus 2-deoxyglucose medium, whereas in those from fed rats a mobilization-resistant portion of about 40% of the TG pool remained. This finding coincided with a lower decay of the contractile and pacemaker activities in the atria from fasted rats. Insulin abolished the TG mobilization in the atria from fed rats in the presence of glucose, but it was ineffective in the fasted atria. These data suggest that the endogenous-TG and glucose share in supporting the atrial functions, that insulin is involved in the control of TG consumption only in the fed state and that the greater TG mobilization in the fasted atria, at least partly, meets the energy requirements of the tissue.

Animals↗
PubMed1988

Fibromatosis.

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Fibroma↗
PubMed1987

Effects of long-chain fatty-acyl esters of coenzyme A and carnitine on cell-free rat heart preparations.

The purpose of this study was to investigate the effects of fatty acyl CoA and carnitine esters on the glycolytic system of the rat heart. Using a respiring incubation mixture containing a whole-heart homogenate it was observed that oleoyl-CoA slowed down the glucose disappearance whereas lactate accumulation did not change. Experiments were also performed by means of an incubation mixture prepared with a soluble heart extract, considered to contain all glycolytic enzymes present in heart fibres. Palmitoyl-CoA or oleoyl-CoA as well as palmitoyl carnitine, added separately or together, were unable to alter the glucose disappearance and lactate accumulation in this mixture. These data suggest that long chain acyl-esters have not direct inhibitory actions on the heart glycolytic activity. However, CoA esters seem to exert indirect inhibitory effects which may be relevant to the myocardium under oxygen restriction situations.

Acyl Coenzyme A↗
PubMed1987

Acute effect of the gastrokinetics cisapride and metoclopramide on the gastric emptying function in patients with the early satiety syndrome.

Ten patients with postprandial upper abdominal discomfort, 4 of them having delayed gastric emptying, were included in a single-blind y camera study aimed at comparing the effects of cisapride and metoclopramide on gastric emptying. The two drugs were given sequentially, at a one-week interval, at a single oral dose of 10 mg, 15 minutes before intake of a labelled ordinary test meal. Applying a power exponential mathematical model to the y-camera data, T1/2 and the shape of the emptying curve were determined. The median half-emptying time (T1/2) was reduced from 81.5 min. in the basal condition to 62.5 min (-23%) after cisapride and to 84.5 min. (-9%) after metoclopramide. As compared with the basal values cisapride significantly (P less than 0005, Wilcoxon Test) reduced the % RRAD from 45 min. after intake of the meal on wards. The onset of action of cisapride was faster (P less than 0.05) than that of metoclopramide. In the main, each of these drugs accelerated evacuation of the meal in the cases of delayed emptying. Cisapride particularly shortened the initial emptying lag and was superior to metoclopramide in this respect.

Adult↗