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Biomedical subjects

A F Almeida

Publications and source records attributed to A F Almeida.

At least 19 recordsLinked to original sources
PubMed1996

Glutamine metabolism is changed in lymphocytes from aged rats.

Changes in the protein content, maximal activity, and Km of phosphate-dependent glutaminase were measured in the lymphoid organs (thymus, spleen, and mesenteric lymph nodes) from just-weaned, mature (3 months), and aged rats (15 months). Also, [U-14C] glutamine transport and decarboxylation and the production of glutamate and aspartate from 2 and 20 mM glutamine were measured in incubated mesenteric lymph node lymphocytes. The ageing process induced a reduction in the protein content of the thymus and spleen, as well as the phosphate-dependent glutaminase activity in the thymus and isolated lymphocytes. The Km of phosphate-dependent glutaminase, however, was not affected by the process. Ageing reduced [U-14C] glutamine decarboxylation and increased glutamate and aspartate production in incubated lymphocytes. The results indicate that the ageing process does modify several aspects of glutamine metabolism in lymphocytes: reduces maximal glutaminase activity and [U-14C] glutamine decarboxylation and increases the Km for [U-14C] glutamine uptake and the production of glutamate and aspartate.

Aging↗
PubMed1995

Sulfide-induced perturbations of the neuronal mechanisms controlling breathing in rats.

The effects of sulfide on neonatal rat respiration were studied. Two in vitro experimental models were utilized: the isolated brain stem-spinal cord preparation and the medullary slice preparation containing respiratory rhythm-generating regions from neonatal rats. Plethysmographic measurements of the effects of sulfide on the breathing patterns of unanesthetized neonatal rats were also made to compare the sensitivities of neonatal and adult rats to sulfide toxicity. In vitro, sulfide acted at sites within the ventrolateral medulla to depress the frequency of respiratory rhythmic discharge by approximately 50-60%. However, the neuronal network underlying respiratory rhythmogenesis continued to function in the presence of concentrations of sulfide far beyond those deemed to be lethal in vivo. Intraperitoneal administration of sulfide caused a dose-dependent decrease in the frequency and amplitude of breathing of neonatal rats of all ages (0-19 days postnatal), although the sensitivity to sulfide increased with age. We hypothesize that the rapid suppression of breathing caused by sulfide is due to changes in neuronal excitability within respiratory rhythm-generating centers rather than, as previously hypothesized, to perturbations of cellular oxidative metabolism.

Aging↗
PubMed1995

Effect of low dose recombinant human omega erythropoietin (rHuEPO) on anaemia in patients on hemodialysis.

The effect of low dose rHuEPO therapy in ESRD patients on regular dialysis therapy was assessed in a prospective study in 22 patients. Routine hematological and biochemical tests, bone marrow aspiration, serum iron and ferritin studies were performed. The quality of life was also assessed. rHuEPO was administered in a dose of 25 units/kg i.v. post dialysis 3 times a week for 8 weeks, followed by 36 units/kg for further 4 weeks. Significant rise (p = 0.0001) in Hb & PCV with rise in reticulocyte count (0.016) was noted. Serum ferritin was a better index of iron status of the body. Significantly improved anemia and quality of life of ESRD patients on hemodialysis was seen in 95% of the patients.

Adult↗
PubMed1994

Left ventricular function in end stage renal disease--non-invasive assessment in patients on maintenance hemodialysis.

Non-invasive assessment of left ventricular function was performed by echocardiography and radionuclide ventriculography in 17 end-stage renal disease patients on maintenance hemodialysis. Patients with diabetes mellitus, ischemic heart disease and pericardial or valvular heart disease were excluded from the study. Parameters studied on echocardiography were left ventricular internal diameter in diastole (LVIDd), left atrial diameter (LAD), Aortic root diameter (ARD), Left ventricular posterior wall thickness in systole (LVPWs), End diastolic volume (EDV), End Systolic volume (ESV), fractional shortening percentage (FS%) and ejection fraction (EF). Parameters studied on radionuclide ventriculography were Peak ejection rate (PER), Peak filling rate (PFR) and Ejection fraction (EF). Significantly abnormal values for echocardiographic parameters LVIDd, LVPWs, EDV, ESV and FS% were found. On evaluation by MUGA scans, it was observed that the PER was significantly decreased while the PFR and EF did not change significantly.

Adolescent↗
PubMed1993

Measurement of serum thyrotropin levels using sensitive immunoradiometricassays in patients with chronic renal failure: alterations suggesting an intact pituitary thyroid axis.

Serum thyroid stimulating hormone (TSH) levels were measured in 127 patients with varying grade of chronic renal failure (CRF). Sensitive immunoradiometricassays (IRMA) were used so that small changes in TSH levels if any, could be appreciated, and to see if such alterations exhibit some relationship with those in thyroid hormone levels. Mean serum TSH levels in the patient group of 2.33 microU/ml (0.07-7.3) was significantly higher in comparison to 1.73 microU/ml (0.25-4.6) in normal subjects (p < 0.001). However, they were not significantly different when measured by radioimmunoassay (RIA) as compared to normals. Serum triiodothyronine (T3), thyroxine (T4) and free triiodothyronine (FT3) levels of 72 +/- 32 ng/dl, 7.4 +/- 2.6 micrograms/dl and 2.9 +/- 0.9 pg/ml were significantly lower than in normal subjects, whereas serum free thyroxine (FT4) showed a slight though not significant elevation. When patients were divided in three subgroups according to the degree of renal insufficiency, TSH levels showed a gradual rise with corresponding depression in their T3, FT3 and T4 levels. In 19 patients who were on hemodialysis (HD) and subsequently received successful renal transplantation, most of the thyroid function parameters returned towards the normals with TSH undergoing significant depression from their pretransplant levels as well as from normal levels. The results indicated that a slight but significant elevation in TSH levels could be revealed by sensitive IRMA in patients with CRF. Rising TSH levels with increasing renal insufficiency and its inverse relationship with T3 and T4 levels suggest maintenance of pituitary thyroid axis.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1992

Fine needle aspiration cytology (FNAC) in the evaluation of acute renal allograft rejection.

310 Fine needle aspirations biopsies (FNAB) were performed in sixty-five live related renal donor transplant recipients in a prospective study over 2 years. 82.8% of FNAB were adequate for opinion and there were no complications after the procedure. Methodology used and interpretation of FNACs was as described by Von Willebrand and Hayry. The procedure of FNAC had a sensitivity of 83.3%, specificity of 98.3% and accuracy of 96.1%, and statistically significant (p < .001) correlation was noted between FNAC and Needle biopsy. The increment in lymphoblasts, lymphocytes and score above 3 was suggestive of acute cellular rejection. Increment in monocytes and macrophages above 1% in addition to other cells, was suggestive of acute vascular rejection. FNAC was found to be a safe, simple and easy procedure with high specificity and sensitivity.

Biopsy, Needle↗
PubMed1991

Total and free thyroid hormone levels in chronic renal failure.

The levels of serum total thyroxine (TT4), triiodothyronine (TT3), free T3, (FT3) free T4 (FT4) and thyrotropin (TSH) were measured in 127 clinically euthyroid patients with varying grades of chronic renal failure (CRF); and 97 healthy individuals. They were grouped as: Group I containing 93 patients on conservative management; Group II containing 34 patients on regular dialysis therapy; and Group III (normals). Group I patients showed significant decrease in TT3, TT4 and FT3 levels (p less than 0.001) as compared to Group III, whereas FT4 and TSH values in group I were not significantly altered. TT3, TT4 and FT3 levels reduced as the severity of renal damage increased. Variations in TT3, TT4, FT3, FT4 and TSH levels in Group II patients were similar to those in Group I, except for a decrease in TSH levels (p less than 0.05) as compared to normals. Several thyroid function tests are abnormal in CRF patients, however, finding of normal FT4 and TSH levels would indicate functional euthyroid status.

Humans↗
PubMed1990

Pattern of renal amyloidosis in western India. A study of 104 cases.

A total of 31,266 autopsies and 1556 renal biopsies were scrutinised over a period of 19 years (1968-1986) retrospectively and prospectively, with an aim to study the incidence and pattern of renal amyloidosis in western India. A total of 104 cases with amyloidosis were detected, 41 from the autopsy series (0.1%) and 63 from biopsies (4%). Secondary amyloidosis was seen in 83.7% and primary amyloidosis in 11.5%. The interval between the onset of predisposing disease and first evidence of amyloidosis varied from 2 months to 31 years. Tuberculosis of various organs was the main cause of secondary amyloidosis (72.4%). Nephrotic syndrome was a common mode of presentation (71.4%). Besides kidneys, which were involved in all cases, the liver, spleen and adrenals were other commonly involved organs at autopsy. Renal failure was the leading cause of death (34.1%).

Adolescent↗
PubMed1989

Acute renal failure due to viperine snake bite as seen in tropical western India.

A wide spectrum of clinicopathological changes have been described in 50 cases of ARF following viperine snake bite studied prospectively over a 15-year period. Disseminated intravascular coagulation (DIC) was seen in 24/50 cases (Russel's viper bite in 62% and Ecchis carinatus bite in 42% of subjects). Histological examination of renal tissue obtained 1.5 days to 8 weeks after the bite revealed proliferative glomerular changes in 17 cases. These were characterized by ballooning of the capillaries, thickening and splitting of glomerular basement membrane (GMB), fibrin thrombi in the capillaries, and mesangial cell proliferation most prominently seen in Ecchis carinatus bites resulting in ARF.

Acute Kidney Injury↗
PubMed1989

Clinicopathological study of acute renal failure following viperine snake bite.

Fifty patients of acute renal failure following Viperine snake bite were studied. Oliguria (100%), local swelling (48%) and bleeding tendencies (42%) were the predominant clinical features encountered. Of the 25 patients in whom detailed coagulation studies were done, 24 patients had disseminated intravascular coagulation (DIC) and 1 had primary fibrinolysis. DIC was commoner with Russell's viper bite (62%) in comparison to Echis carinatus bites (40%). Renal histology obtained in 29 cases revealed tubular necrosis (35%), cortical necrosis (24%) tubular degeneration (17%) and glomerular changes (17%). Ballooning of glomerular capillaries (59%), splitting of glomerular basement membrane (40.7%), swelling of endothelial cells (29.6%), and focal proliferation of mesangial cells (17%) were the significant glomerular changes encountered. 20 (40%) patients succumbed, DIC (50%), irreversible shock (30%) and septicaemia (20%) being the immediate causes of death. Development of oliguria within 24 hours of snake bite and cortical necrosis were associated with higher mortality.

Acute Kidney Injury↗
PubMed1987

Regulation of the number of Na+,K+-pump sites after mitogenic activation of lymphocytes.

The early activation of Na+,K+-ATPase-mediated ion fluxes after concanavalin A (ConA) stimulation of pig lymphocytes is caused by an increase in intracellular Na+ concentration. A second mechanism of regulation of Na+,K+-ATPase activity becomes apparent between 3 and 5 h after mitogenic stimulation, but prior to onset of increase in cell volume; this consists of an increase (about 75%) in the number of ouabain-binding sites (from 35 X 10(3) +/- 12 X 10(3)/cell in resting to 60 X 10(3) +/- 27 X 10(3)/cell in activated lymphocytes). The increase in ouabain binding was attributed to an increase in the number of active Na+,K+-ATPase molecules, based on the following evidence: there was an increase in the Vmax of ouabain binding, without variation in the Km; the increase in ouabain binding was accompanied by a proportional increase in K+ influx, when the assay was performed in the presence of the Na+ ionophore monesin, which was used to eliminate the difference in intracellular Na+ concentration between resting and activated cells; there was proportionality between ouabain-inhibitable ATPase activity in permeabilized cells and the number of ouabain-binding sites in resting and activated lymphocytes. The ConA-induced increase in ouabain-binding sites was influenced neither by amiloride nor by incubation in low Na+ medium, under conditions which prevented both increase in intracellular Na+ concentration and K+ influx. Increase in intracellular Na+ concentration was ineffective in altering the number of active pump molecules in resting cells. During incubation with ConA, the presence of ouabain did not affect the increase in ouabain-binding sites; thus, regulation of the number of pump sites is independent of the regulation of their activity. The ConA-induced increase in number of ouabain-binding sites did not require protein synthesis; indeed, cycloheximide, anisomycin, and puromycin, under conditions in which they inhibited protein synthesis by by 95%, induced the increase to approximately the same extent as did ConA. This suggests the presence in resting lymphocytes of a rapidly turning over protein that either prevents the ATPase subunits from assembling or from integrating into the membrane.

Animals↗