Search PubMed⌕ Search

Biomedical subjects

D T Covas

Publications and source records attributed to D T Covas.

25 records · Page 2Linked to original sources
PubMed1986

Red cell pits appear preferentially in old cells after splenectomy.

The percentage of erythrocytes with pits in the peripheral blood after splenectomy was followed in 4 patients. The pit counts started to increase soon after surgery and were above 20% on the 20th postsplenectomy day. The results demonstrate that the majority of pits developed in circulating erythrocytes. Two other patients with autoimmune hemolytic anemia who had failed to respond to splenectomy presented an increase of pit counts from 5.5-13% to 29.8-47.4%, accompanying an increase of erythrocyte life-span during corticosteroid treatment. The data indicate that pits are formed preferentially in older erythrocytes.

Anemia, Hemolytic, Autoimmune↗
PubMed1986

Discrepancy between pit counting and spleen function tests in nutritional anemias and hemoglobinopathy C.

An increased percentage of erythrocytes with crater-like indentations (pits) when viewed under interference contrast microscopy is accepted as indicative of splenic hypofunction. The percentage of pitted erythrocytes was above the upper limit of the normal range (0.0-3.2%) in 6 patients with megaloblastic anemia (4.6-22.6%), 8 patients with iron deficient anemia (5.6-21.0%) and 6 patients with HbC diseases (12.5-45.0%). However, the spleen function was normal or hyperactive when evaluated by the rate of removal from the circulation of heat-damaged 99mTc-labeled autologous erythrocytes. Thus, in these diseases, there is a discrepancy between pit counting in the peripheral blood and other spleen tests.

Adolescent↗
PubMed1985

Aspects of splenic hypofunction in old age.

The weight of the human spleen decreases in old age. The percentage of erythrocytes with pits observed by interference contrast microscopy was significantly higher in 39 elderly subjects (median 4.2%, range 1.2%-14.6%) than in 34 younger controls (median 1.4%, range 0.6%-6.2%). Further evidence of splenic hypofunction was obtained from 7 elderly people with increased pit counts: the removal from circulation and accumulation into the spleen of heat-damaged autologous erythrocytes was abnormally slow. However, no difference in the spleen area of the same subjects measured by scintillation scanning was observed in comparison with normals. Thus, the weight reduction of spleen in old age is accompanied by a decrease in splenic function.

Adolescent↗
PubMedDate not supplied

The frequency of blood-born viral infections in a population of multitransfused Brazilian patients.

The frequency of viral markers for hepatitis B (HBV) and C (HCV), human immunodeficiency virus-1 (HIV-1) and human T-lymphotropic virus-1 (HTLV-1) was evaluated in 32 Brazilian beta-thalassemia multitransfused patients. Additionally the serum concentrations of ferritin and alanine aspartate transaminase (ALAT) were determined. The results show a high prevalence of markers of infection by HBV (25.0%) and HCV (46.8%) and a low prevalence of markers for HIV-1 and HTLV-1. No correlations were demonstrated between the presence of the hepatitis markers and the number of units transfused or the serum concentrations of ferritin and ALAT.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Use of polimerase chain reaction for neonatal diagnosis of human immunodeficiency virus type 1 (HIV-1) perinatal infection].

The polymerase chain reaction (PCR) was evaluated for its ability to diagnose perinatal HIV-1 infection before the development of signs or symptoms of the disease in thirty-seven infants (median age of 5.5 days) born to HIV-1 infected women. Of 30 children with complete follow up (median of 25 months), 9 (30%) had serological and clinical features of HIV-1 infection and 21 (70%) were uninfected. Among the infected infants, 5/9 (56%) had positive neonatal PCR tests and 4/9 (44%) had negative PCR tests. None of the 21 uninfected children had positive PCR tests. The prognosis of HIV-1 disease in infected infants with a positive neonatal PCR positive test was similar to that of infected infants with a negative PCR test. In spite of not identifying all the infected infants, the PCR test is a useful tool for early diagnosis of HIV-1 perinatal infection, detecting infected newborns during gestation.

English Abstract↗