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Biomedical subjects

S Rao

Publications and source records attributed to S Rao.

At least 361 records · Page 20Linked to original sources
PubMed1985

Increased activation of the alternative complement pathway in sickle cell disease.

Complement proteins play an important role in host defenses against Streptococcus pneumoniae, a major cause of serious infections in sickle cell (SS) disease. Previous studies have suggested abnormalities of the alternative complement pathway in SS disease. We measured activation of the alternative pathway in sera from patients with SS disease utilizing an enzyme immunoassay which detects C3b,P complexes, derivative of the C3b,Bb,P alternative pathway convertase. In all, 89% of SS sera had elevated concentrations of C3b,P complexes, indicative of increased alternative pathway activation. Chronic activation of the alternative pathway may contribute to impaired host defense in SS patients.

Anemia, Sickle Cell↗
PubMed1985

Scintigraphic differentiation of bone infarction from osteomyelitis in children with sickle cell disease.

Bone scans or bone marrow scans or both were obtained during 42 episodes of bone pain in 40 children with sickle cell disease, and the usefulness of these procedures was compared. On the basis of the subsequent clinical course, a diagnosis of bone infarction was made in 34 episodes, and osteomyelitis in eight. Among 22 patients with bone infarction, uptake on bone scan was increased in 14, decreased in three, and normal in five. Seven of eight patients with osteomyelitis had increased uptake on bone scan; one had normal uptake. In contrast, marrow scan uptake was markedly decreased in 15 of 16 patients with bone infarction, and was normal in five of five patients with osteomyelitis. Thus, decreased uptake on bone marrow scan in a patient with sickle cell disease and bone pain almost invariably indicates infarction, whereas normal uptake strongly suggests the diagnosis of osteomyelitis. We found marrow scans more useful than bone scans for this differential diagnosis.

Adolescent↗
PubMed1985

Correlation of serum opsonins with in vitro phagocytosis of Streptococcus pneumoniae.

C-reactive protein (CRP), an acute-phase reactant which binds to phosphocholine (PC) in the pneumococcal cell wall, and anti-PC antibodies are protective against experimental pneumococcal bacteremia in mice. To determine the relative opsonic capacities of CRP and anti-PC compared with those of antibodies against pneumococcal capsular polysaccharides (anti-PCP), we correlated in vitro opsonic activity for serotype 7F Streptococcus pneumoniae with concentrations of CRP, anti-PC, and anti-type 7F PCP in human sera from 10 normal subjects and 38 patients with sickle cell (SS) disease, a high-risk group for pneumococcal infection. Opsonic activity, measured by a radiolabeled bacterial uptake assay, correlated with anti-PCP levels but not with CRP or anti-PC in both the normal subjects and patients with SS disease. Addition of CRP to normal sera did not increase opsonic activity for serotypes 4 and 7F S. pneumoniae, although it did so for serotype 27, a nonpathogenic strain unique for having PC in its capsule. CRP and anti-PC were not effective opsonins when they bound to the pneumococcal cell wall rather than the capsule. The protective effects of CRP or anti-PC against these serotypes may be produced by means other than complement-dependent opsonization.

Adult↗
PubMed1985

Evaluation of chromosomal damage in males exposed to agent orange and their families.

Agent Orange (AO), a phenoxyherbicide, and dioxin, an impurity found in AO, are considered clastogens, mutagens, and teratogens in plants and animals. AO has come under suspicion in humans following claims that it causes chromosome damage and birth defects in offspring of exposed individuals. No well-designed epidemiological studies are available to support this conclusion. Of ten exposed individuals studied for chromosome breaks and sister chromatid exchange frequencies, eight were ascertained because they had children with congenital defects. No consistent pattern of anomalies was observed. Five children had neurologic deficit, one child had a central nervous system anomaly, and one child was affected with glaucoma. Although all individuals studied had normal karyotypes, a statistically significant increase in chromosome breakage was observed in exposed males compared to their unexposed wives and children; sister chromatid exchange frequency was not increased.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1985

Automatic processing of word meaning: intralingual and interlingual interference.

Automatic processing of word meaning was studied in bilingual children and children in various stages of second-language acquisition in 2 experiments. A picture-word interference task was used. The children named outlined pictures as rapidly as possible while attempting to ignore distractor words printed inside the pictures' borders. For children proficient in the 2 languages (Experiment 1), the printed distractors interfered with naming on both intralingual trials, for which the distractor and naming language were the same, and on interlingual trials, for which they were different. The pattern of interference across 6 levels of name-distractor relation was similar for the intralingual and interlingual conditions and indicated that at least part of the interference occurred at a semantic level. For children who were in various phases of learning a second language (Experiment 2), second-language words were automatically processed to the level of meaning early in the course of second-language reading instruction. As was found for the more proficient groups, both the pattern and the amount of interlingual interference matched that for intralingual interference. The results question whether an "input switch" operates for bilingual word processing.

Adolescent↗
PubMed1984

Studies of lipoprotein metabolism in a patient with fish-eye disease.

In the rare familial disorder fish-eye disease, hypertriglyceridaemia is associated with elevated levels of very-low-density lipoprotein (VLDL) and enrichment of low-density lipoprotein (LDL) with triglyceride. The kinetic basis of the dyslipoproteinaemia was investigated by studying the metabolism of the apolipoprotein-B moeity of VLDL, intermediate-density lipoprotein (IDL) and LDL in a 68-year-old woman with this condition. The major kinetic abnormality was a pronounced reduction in the rate of fractional conversion of VLDL-B to IDL-B and of IDL-B to LDL-B, suggesting that the dyslipoproteinaemia represents accumulation in plasma of partly degraded products of VLDL metabolism. This kinetic disorder has features in common with type-III hyperlipoproteinaemia. In studies in vitro no defect in the enzyme, activator or substrate components of the lipoprotein lipase or hepatic lipase systems was observed.

Aged↗
PubMed1984

Retrospective analysis of 58 children with retinoblastoma.

We performed a retrospective analysis of 58 children with retinoblastoma seen at the University of Illinois at Chicago between 1960 and 1982. Our findings showed an almost equal distribution by sex, a predominance (69%) of white patients, and a common presenting symptom (70%) of leukocoria, with (22%) or without (48%) strabismus. Unilateral involvement was noted in 35 patients (60%). Of the 23 (40%) bilaterally affected children, 19 had simultaneous involvement at the time of diagnosis. All bilateral and 90% of the unilateral cases were diagnosed before age five years. Family history was positive for retinoblastoma in five bilateral and one unilateral case. At the time of diagnosis, 35 patients had stage V disease (Reese-Ellsworth classification, Table 1). Depending on the stage of disease treatment included enucleation, radiation, and chemotherapy. Mortality was 25% from 1960 to 1974, and zero thereafter.

Age Factors↗
PubMed1983

Oral glucose tolerance tests in newborn infants.

Oral glucose tolerance tests ( GTTs ) were performed on 15 fullterm (Group I), 12 preterm low birth weight (Group II) and 16 preterm very low birth weight (Group III) infants who were clinically stable. GTT was done on the third postnatal day in Groups I & II and serially at different postnatal ages in Group III (days 3, 7, 14, 21 & 28). After 4 hours of fasting capillary blood samples were collected for plasma glucose estimation at fasting and for a 3-hour period following oral intake of 1.75 gm/kg of glucose. Mean plasma glucose levels were comparable in Groups I & II at all stages. Group III infants had lower mean plasma glucose which increased with postnatal age. Significantly higher values were observed as late as 150 minutes in days 3, 7 & 14 groups compared with days 21 and 28 of Group III. Our data suggest that larger and more mature preterm low birth weight infants (greater than or equal to 1501 gm and greater than or equal to 34 weeks' gestation) were capable of handling glucose as efficiently as term infants. Preterm very low birth weight infants (less than or equal to 1500 gm and less than or equal to 33 weeks' gestation) exhibited impaired glucose tolerance during the first two weeks of life.

Blood Glucose↗