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Biomedical subjects

S Pereira

Publications and source records attributed to S Pereira.

At least 73 records · Page 4Linked to original sources

Detection of a Cytosolic Glutamine Synthetase in Leaves of Nicotiana tabacum L. by Immunocytochemical Methods.

Two glutamine synthetase (GS) polypeptides (44 and 39 kD) were immunodetected on western blots of leaf extracts from tobacco (Nicotiana tabacum L.), a plant that has been reported to contain only chloroplast GS in the leaves. By immunocytochemical methods, we confirmed the localization of GS in the cytosol of cells in the vascular tissue and in the chloroplasts of mesophyll cells.

Journal Article↗

The relationship of microbial pathogens to acute infectious diarrhoea of childhood.

Bacterial, viral and parasitic enteric pathogens were detected in 692 of 916 children below 36 months of age with acute diarrhoea and in 289 of 587 matched controls. The rates of identification of only four groups of pathogens, rotavirus, Shigellae, Salmonella typhimurium and enterotoxigenic E. coli, were significantly higher in the patients. The prevalence of a variety of other enteric pathogens was similar in controls of patients. Shigellosis had a characteristic clinical profile but none of the other agents could be suspected on clinical grounds. The high prevalence of pathogens in controls suggested that the population may be partially protected against a variety of enteric pathogens and that final common pathways leading to diarrhoea may be activated by changes in the microbial ecology of the gut lumen.

Acute Disease↗

Ascites adenosine deaminase activity is decreased in tuberculous ascites with low protein content.

The value of adenosine deaminase activity (ADA) in ascitic fluid was examined in 12 patients with confirmed peritoneal tuberculosis and compared with that of 96 patients with ascites of other different etiologies as an age-matched control group, to determine the diagnostic value of the ADA activity in tuberculous ascites. The mean adenosine deaminase activity (ADA) value in ascitic fluid of the tuberculous peritonitis group was 47.9 +/- 21.9 IU/L and in the control group 9.6 +/- 5 U/L (mean +/- SD); p less than 0.01. A different method than that usually reported in tuberculous peritonitis was used for ascites ADA estimation. The best sensitivity and specificity was obtained when greater than 32 U/L was used as a cutoff point. The ascites ADA activity correlated with the ascites total protein concentration in the tuberculosis group (r = 0.842). Our findings confirm other results and support the ADA activity determination in ascitic fluid as a useful noninvasive screening test in the diagnosis of peritoneal tuberculosis in endemic areas or in high risk patients. However, false-negative results may occur in those patients in which ascites total protein concentration is low.

Adenosine Deaminase↗

[Morphologic course of the left ventricle after renal transplantation. Echocardiographic study].

OBJECTIVE: To characterize and to quantitate the morphologic changes in left ventricle, in renal transplant patients (Pts) treated with cyclosporine, through sequential echocardiographic examinations. DESIGN: A prospective study of renal transplant patients, between October/88 and May/89, who maintained good function of the renal graft during the follow-up. SETTING: Cardiology and Nephrology departments of Santo António Hospital. MATERIAL AND METHODS: 20 patients, 13 men and 7 women, mean age of 33 +/- 10, ranging from 20 to 56, constitute the final group of the study. These patients have been receiving dialysis during 3.8 +/- 2.3 years (0.4-8). Seven patients were excluded, five by echocardiographic criteria and another two because of chronic renal graft disfunction (creatinine greater than 2.0 mg%). The echocardiographic examinations were performed during the first week, and 1, 2, 3, 6 and 12 months after renal transplantation. The following measurements were performed: left ventricular end-diastole diameter (LVED), interventricular septal thickness (IVST), posterior wall thickness (PWT) and left ventricular mass index (LVMI). The measurements were obtained in M-mode following the conventional recommendations. Average values of at least 3 cardiac cycles were used. Heart rate, blood pressure, creatinine, hematocrit, body surface area and fistula patency, were determined at the time of each echocardiogram. MAIN RESULTS: The LVED decreased progressively until the third month, from 51.9 +/- 7 mm to 47.8 +/- 6 mm (p less than 0.001), remaining stable thereafter. The baseline value of IVST, 13.6 +/- 5 mm, was similar at the twelfth month, 13.8 +/- 2 mm (ns). The baseline value of PWT, 13.7 +/- 4 mm, decreased gradually since the second month, having reached 12.7 +/- 2 mm at the twelfth month (ns). The LVMI (g/m2) reduced progressively, from 243 +/- 82 to 190 +/- 38 at the end of the study (p less than 0.05. A high incidence of arterial hypertension was detected during the follow-up period; at the twelfth month, 18 patients (90%) were on antihypertensive drug therapy, 11 of which had blood pressure greater than or equal to 160/95 mmHg. CONCLUSIONS: We verified, one year after the renal transplantation, a significant decrease of LVMI, that was mainly determined by the LVED reduction. Left ventricular walls thickness had no significant variation; we think that the high incidence of hypertension during the follow-up period, in part due to the pressure effect of cyclosporine, may have been responsible for this fact.

Adult↗

Haemolytic uraemic syndrome with prolonged anuria and cortical calcification: a case report.

An 18-month-old infant presented with haemolytic uraemic syndrome following a prodrome of colitis. Incomplete recovery of renal function occurred after 4 weeks of anuria and was associated with extensive renal cortical calcification. During the recovery phase he had two relapses of colitis, microangiopathic haemolytic anaemia and thrombocytopenia without any deterioration in renal function.

Anuria↗

New Secale cereale (rye) DNA derivatives for the detection of rye chromosome segments in wheat.

Subcloning of a clone of the 120-bp family of rye, pSc119, has produced two extremely useful probes. pSc119.1 assays rye-specific dispersed repetitive sequence families. It is present on all seven rye chromosomes and hybridizes to the entire length of each chromosome, with the exception of some telomeres and the nucleolar organiser region. pSc119.2, in contrast, hybridizes predominantly to the telomeric regions of rye chromosomes, with some interstitial sites. Unlike pSc119.1, it assays similar repetitive sequence families in both wheat and rye chromosomes.

Chromosomes↗

Cytoproteic CSF findings in 33 MS patients: usefulness for diagnosis.

Although multiple sclerosis (MS) is mainly defined on clinical grounds, CSF parameters still remain important diagnostic and scoring tools. To demonstrate the usefulness of some easy laboratory techniques, a CSF cytomorphological and agarose gel electrophoresis (AGE) evaluation was undertaken in 33 MS patients: 79% presented a lymphoid cell profile and in 73% the gamma globulin fraction was abnormal. In the great majority of cases (97%) either or both cytological and electrophoretical abnormalities were found.

Adolescent↗

Effect of bezafibrate on the sequelae of acute experimental focal cerebral ischaemia.

The possibility that the ability of bezafibrate to lower the oxygen affinity of haemoglobin might lead to an increased oxygen delivery to ischaemic cerebral tissue was explored in preliminary studies in two animal models. The combined morbidity and mortality of unilateral carotid ligation in the gerbil appeared to be reduced at two hours in bezafibrate treated animals. By four hours and thereafter the outcome was unaffected. Two hours after MCA occlusion bezafibrate-treated rats showed a significantly reduced rise in tissue lactate concentration (p less than 0.01) suggesting less anaerobic metabolism had occurred in the ischaemic tissue.

Acute Disease↗

Do leukocytes have a role in the cerebral no-reflow phenomenon?

The possible role of leukocytes in the cerebral microcirculation following ischaemia was assessed in the gerbil. The no-reflow phenomenon seen after 30 minutes of severe bilateral hemispheric ischaemia during hypotensive reperfusion was compared in control animals and in a group made leukopenic by pretreatment with cyclophosphamide. Neither the incidence nor the severity of the no-reflow phenomenon differed between the two groups. The evidence from this study casts doubt on the hypothesis that leukocyte plugging plays a major role in the cerebral microcirculation's response to ischaemia.

Animals↗

Acute renal failure in infants in the tropics.

This study records our experience with 40 infants who developed acute renal failure in a tropical environment over a period of 2 years. All the patients required intermittent peritoneal dialysis. Septicaemia (88%) and acute gastroenteritis (55%) constituted the leading causes of acute renal failure. Haemolytic uraemic syndrome was present in six (18%) patients. An elevated serum creatinine (85%), metabolic encephalopathy (75%), uncompensated metabolic acidosis (75%) and hyperkalaemia (48%) were the major indications for dialysis, while fluid overload was present in only 18% of the infants. Intermittent peritoneal dialysis was used in all the patients and was found to be effective. Procedural complications were minor and infrequently encountered. The clinical course and laboratory data consistent with haemolytic uraemic syndrome was observed in six patients, and acute tubular necrosis was the predominant renal lesion in the remainder. Mortality was 75%. The aetiology of acute renal failure in infants in the tropics differs significantly from that in the West, and even within a given country marked regional variations exist.

Acute Kidney Injury↗

Autoantibodies and immunogenetics in 30 patients with systemic sclerosis and their families.

Clinical and serological evidence of connective tissue disease was found in a high proportion of 132 family members of 30 patients with systemic sclerosis. In 20 probands with the milder CREST form of the disease, 10 had HLA-DR5 and 12 had null alleles at the C4 loci. None of 11 probands with more severe systemic sclerosis had HLA-DR5; all 11 had null alleles at the C4 loci. All but two of the probands had either HLA-DR5 or a C4 null allele, and this was also the case for the majority of the relatives with autoantibodies. Genetic markers of the major histocompatibility complex, including HLA-DR5 and C4 null alleles, appear to be closely associated with markers of disease in these probands and their families.

Antibodies, Antinuclear↗

Genetic susceptibility to scleroderma-like syndrome in symptomatic and asymptomatic workers exposed to vinyl chloride.

We have previously reported a genetic susceptibility to a scleroderma-like disorder in a group of workers exposed to polyvinyl chloride and this susceptibility could be mapped to the major histocompatibility complex area of the 6th chromosome. To date no genetic studies have been reported comparing affected with unaffected workers. We report such data and discuss it in the light of our previous findings in vinyl chloride exposed patients and in patients with classical scleroderma. Our results suggest that susceptibility to this disorder is increased in the presence of HLA-DR5 or of a gene in linkage disequilibrium with it and an antigen associated with the haplotype A1 B8, while DR3 favours progression of the disease.

Chemical Industry↗

Immature B cells in fetal development and immunodeficiency: studies of IgM, IgG, IgA and IgD production in vitro using Epstein-Barr virus activation.

Epstein-Barr virus has been used as a B cell mitogen to explore the parallels between the B cells found in patients with hypogammaglobulinemia and the immature B cells in fetal tissues. Peripheral blood lymphocytes from 29 cases of late onset hypogammaglobulinemia (common variable immunodeficiency) and from 10 cases of X-linked hypogammaglobulinemia were depleted of T lymphocytes and stimulated with virus in vitro. Immunoglobulin production was measured over a 4-week culture period using inhibition radioimmunoassays for IgM, IgG, IgA and IgD. The results were compared with those seen with fetal liver cells, cord blood lymphocytes and adult lymphocytes. Virus-stimulated cells from fetal sources produced small amounts of IgG and IgA relative to IgM, the ratio of IgM to IgG in the second week being in all cases greater than 10. Similar patterns were seen in 25/29 cases of late onset hypogammaglobulinemia, and in the eight cases of X-linked hypogammaglobulinemia that responded in vitro. In contrast, the ratio of IgM to IgG was always less than 8 in cultures of normal adult peripheral blood or bone marrow lymphocytes, and also in cultures from four cases of hypogammaglobulinemia known independently to have abnormal circulating suppressor cells. Eight cases of selective IgA deficiency showed reduced IgA production; six of these showed a normal ratio of IgM to IgG production. Thus, the B lymphocytes which circulate in many patients with hypogammaglobulinemia are functionally immature.

Adult↗

Effects of deoxyadenosine on the activation of ADA inhibited T & B cells.

Using an in vitro model of adenosine deaminase deficiency, we have shown that the triggering of T lymphocyte proliferation by PHA is inhibited by concentrations of deoxyadenosine likely to occur in the plasma of ADA deficient children with severe combined immunodeficiency (ADA-SCID). Prostaglandin E1 increases the sensitivity of T cells to this inhibition, suggesting that derangement of cyclic nucleotide metabolism underlies the profound T lymphopaenia seen in ADA-SCID and in patients treated with the ADA inhibitor, deoxycoformycin. The proliferation and Ig synthesis of ADA inhibited B cells stimulated with protein A and EBV is in general less sensitive to the inhibitory effects of deoxyadenosine. However, this sensitivity varies widely between experiments suggesting that other cells present in the cultures may modify the inhibitory effect of deoxyadenosine. This may help explain the variability in B cell numbers and function in patients with ADA-SCID.

Adenosine Deaminase↗