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Biomedical subjects

S Raman

Publications and source records attributed to S Raman.

At least 55 records · Page 3Linked to original sources
PubMed2000

Characterization of human symptomatic rotavirus isolates MP409 and MP480 having 'long' RNA electropherotype and subgroup I specificity, highly related to the P6[1],G8 type bovine rotavirus A5, from Mysore, India.

In an epidemiological study of symptomatic human rotaviruses in Mysore, India during 1993 and 1994, isolates MP409 and MP480 were isolated from two children suffering from severe, acute dehydrating diarrhea. Both isolates exhibited 'long' RNA pattern and subgroup I specificity suggesting the likelihood of their animal origin. Both isolates did not react with monoclonal antibodies (MAbs) specific for serotypes G1 to G6 as well as G10. To determine the genetic origin of these isolates, complete nucleotide sequences of genes encoding the outer capsid proteins VP4 and VP7, nonstructural proteins NSP1 and NSP3 and viral enterotoxin protein NSP4 from MP409 and partial sequences of genes from MP480 were determined. Comparison of the 5' and 3' terminal sequences of 250 nucleotides revealed complete identity of the gene sequences in both strains suggesting that MP409 and MP480 are two different isolates of a single strain. Comparison of the nucleotide and deduced amino acid sequences of VP4, VP7, NSP1 and NSP3 of MP409 with published sequences of strains belonging to different serotypes revealed that both outer capsid proteins VP4 and VP7 and NSPI are highly related to the respective proteins from the P6[1], G8 type bovine rotavirus A5 isolated from a calf with diarrhoea in Thailand and that the NSP3 is highly homologous to that of bovine rotaviruses. The NSP4 protein showed greatest sequence identity with NSP4s belonging to the KUN genetic group to which NSP4s from human G2 type strains and bovine rotaviruses belong. MP409 and MP480 likely signify interspecies transmission of P6[1], G8 type strains from cattle to humans and represent the first P6[1] type rotaviruses isolated in humans. These and our previous studies on the asymptomatic neonatal strain 1321 are of evolutionary and epidemiological significance in the context of close association of majority of the Indian population with cattle.

Amino Acid Sequence↗
PubMed2000

Mutations in ATRX, encoding a SWI/SNF-like protein, cause diverse changes in the pattern of DNA methylation.

A goal of molecular genetics is to understand the relationship between basic nuclear processes, epigenetic changes and the numerous proteins that orchestrate these effects. One such protein, ATRX, contains a highly conserved plant homeodomain (PHD)-like domain, present in many chromatin-associated proteins, and a carboxy-terminal domain which identifies it as a member of the SNF2 family of helicase/ATPases. Mutations in ATRX give rise to characteristic developmental abnormalities including severe mental retardation, facial dysmorphism, urogenital abnormalities and alpha-thalassaemia. This circumstantial evidence suggests that ATRX may act as a transcriptional regulator through an effect on chromatin. We have recently shown that ATRX is localized to pericentromeric heterochromatin during interphase and mitosis, suggesting that ATRX might exert other chromatin-mediated effects in the nucleus. Moreover, at metaphase, some ATRX is localized at or close to the ribosomal DNA (rDNA) arrays on the short arms of human acrocentric chromosomes. Here we show that mutations in ATRX give rise to changes in the pattern of methylation of several highly repeated sequences including the rDNA arrays, a Y-specific satellite and subtelomeric repeats. Our findings provide a potential link between the processes of chromatin remodelling, DNA methylation and gene expression in mammalian development.

Blotting, Southern↗
PubMed2000

Relationship between fetal femur diaphysis length and neonatal crown-heel length: the effect of race.

OBJECTIVE: To determine whether racial differences affect the relationship between the fetal femur diaphysis length and the neonatal crown-heel length. DESIGN: A prospective study in a teaching hospital with a multiracial population. SUBJECTS: Four hundred and fifty pregnant women (150 Malays, 150 Chinese and 150 Indians) who delivered live infants. METHODS: Ultrasound scan measurement of the fetal femur diaphysis length was carried out within 48 h of delivery in all cases. The relationship between the neonatal crown-heel length and the femur diaphysis length was obtained by regression using the method of least squares. Dummy or indicator variables were used to determine the effect of race on the relationship. RESULTS: The relationship between the neonatal crown-heel length and the femur diaphysis length in all three races was well described by a linear model but a quadratic model described the relationship better. There was no significant difference in relationship of the neonatal crown-heel length and the femur diaphysis length between the Malay and Chinese populations, but the relationship in the Indian population was significantly different was from both the Chinese and Malay. For a given femur diaphysis length, the crown-heel length of the Indian population was found on average to be 1.1 cm shorter than the crown-heel length of the Malay and Chinese populations. CONCLUSION: Differences in fetal body proportions exist between some races. The longer femur diaphysis length noted in certain races does not necessarily imply that the corresponding crown-heel length is longer. These inter-racial differences may increase the error of fetal weight and length estimates if formulae, which have been derived from samples racially dissimilar to that of the target population are used.

Adolescent↗
PubMed1998

Distinct but overlapping expression patterns of two vertebrate slit homologs implies functional roles in CNS development and organogenesis.

The Drosophila slit gene (sli) encodes a secreted leucine-rich repeat-containing protein (slit) expressed by the midline glial cells and required for normal neural development. A putative human sli homolog, SLIT1, has previously been identified by EST database scanning. We have isolated a second human sli homolog, SLIT2, and its murine homolog Slit2. Both SLIT1 and SLIT2 proteins show approximately 40% amino acid identity to slit and 60% identity to each other. In mice, both genes are expressed during CNS development in the floor plate, roof plate and developing motor neurons. As floor plate represents the vertebrate equivalent to the midline glial cells, we predict a conservation of function for these vertebrate homologs. Each gene shows additional but distinct sites of expression outside the CNS suggesting a variety of functions for these proteins.

Amino Acid Sequence↗
PubMed1998

The pregnancy outcome of acyanotic heart disease.

OBJECTIVE: To study the pregnancy outcome of women with acyanotic heart disease. METHOD: This is a retrospective study from a tertiary referral centre in a developing country over a period of 3 years. RESULTS: There were a total of 19,151 deliveries where 143 cases had heart disease in pregnancy, all of which were acyanotic, giving an incidence of 0.7%. Fifty-one (38.4%) of these were congenital whereas 82 (61.6%) were acquired. There was no cyanotic heart lesion during this study period. The fetal and maternal outcome of the women with heart disease (study group) was compared with the general obstetric population in the Unit (control group) using the Chi-squared test. Ninety-two percent in the study group were asymptomatic (NYHA Class I). The age distribution were no different except in the < 20 years interval where there were significantly fewer in the study group. More women with heart disease were primiparous and fewer were multiparous as compared with the controls. There was no significant difference in the rate of induction of labour (9.8% vs 11.8%). The use of epidural analgesia was significantly higher in the study group (49% vs 13%) as was the instrumental delivery rates (35.7% vs 5.7%) when compared with the controls. The caesarean section rate was no different. The mean gestation of babies born to mothers with heart disease was 38.2 weeks. Significantly fewer babies were in the 3.0-3.5 kg weight interval and more in the 2.5-3.0 kg interval. However, this did not alter the perinatal mortality rates which was not significantly different (15.3 vs 14.0 per thousand). CONCLUSION: The fetal and maternal outcome in women with acyanotic heart disease was favourable. It is advocated that the management of these cases should be multidisciplinary to optimise care for these patients.

Adult↗
PubMed1998

Cystic fibrosis transmembrane conductance regulator activation by cAMP-independent mechanisms.

Recent studies have demonstrated that several compounds with diverse structures can activate wild-type cystic fibrosis transmembrane conductance regulator (CFTR) by non-receptor-mediated mechanisms. Some of these compounds have been shown to enhance cAMP-dependent activation of DeltaF508-CFTR. This study was undertaken to compare the mechanisms by which genistein, IBMX, milrinone, 8-cyclopentyl-1, 3-dipropylxanthine (CPX), the benzimidazolone NS004, and calyculin A increase CFTR activity. Our studies demonstrate that, in transfected NIH-3T3 cells, maximal enhancements of forskolin-dependent DeltaF508-CFTR activity are greatest with genistein, IBMX, and NS004. Milrinone, genistein, CPX, NS004, and calyculin A do not increase cellular cAMP. Because forskolin and calyculin A increase in vivo phosphorylation of cAMP binding response element (CREB), the inability of milrinone, genistein, CPX, and NS004 to increase CREB phosphorylation suggests that they do not stimulate protein kinase A or inhibit phosphatase activity. Our data suggest that the mechanisms by which genistein and NS004 activate CFTR differ. We also demonstrate that, in NIH-3T3 cells, IBMX-dependent enhancement of cAMP-dependent CFTR activity is not due to an increase in cellular cAMP and may involve a mechanism like that of genistein.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Survival rates among Canadian children and teenagers with cancer diagnosed between 1985 and 1988.

PURPOSE: To describe the survival rates among Canadian children and teenagers with cancer diagnosed between 1985 and 1988 using population-based data, specifically for the more common forms of childhood cancer, and to assess the effect of age at diagnosis and sex as prognostic factors for selected childhood cancers. DESIGN: Retrospective survival study based on incident cases of cancer identified by the National Cancer Incidence Reporting System and follow-up ascertained by computer record linkage to the Canadian Mortality Database. SUBJECTS: A total of 4409 patients with cancer first diagnosed at 19 years of age or younger between 1985 and 1988, and followed up to Dec. 31, 1991. MAIN OUTCOME MEASURES: Survival rates calculated at 1, 3 and 5 years according to the actuarial life table and the proportional hazards models. RESULTS: The 5-year survival rate for all cancers combined was 71%. Females with acute lymphoblastic leukemia and astrocytoma had markedly higher survival rates than their male counterparts (p < 0.05). Age at diagnosis was a significant predictor of survival among children with acute lymphoblastic leukemia or acute nonlymphoblastic leukemia (p < 0.01), infants having a substantially poorer prognosis than older children. Conversely, the survival rate among infants with neuroblastoma was higher than that among older children, 87% surviving for 5 years after diagnosis. CONCLUSIONS: The survival rate among Canadian children and teenagers with cancer is favourable in relation to the rate among adults with cancer. Nonetheless, the 5-year survival rates for several childhood cancers remain poor (i.e., less than 65%). The survival rates among Canadian children with cancer are similar to those among children with cancer in other developed countries.

Adolescent↗
PubMed1997

Single-dose antibiotic prophylaxis in women undergoing elective caesarean section.

This prospective, randomised, controlled trial was performed to evaluate the effectiveness of single-dose antibiotic prophylaxis in decreasing the infectious morbidity following elective caesarean section. Two hundred women undergoing elective caesarean section were randomly assigned to receive either 1.2 g of Augmentin intravenously, or no treatment, just before the start of their caesarean section. The two groups of women were comparable in terms of patient characteristics and operation variables. The overall postoperative morbidity rate was 19% in the Augmentin treated group versus 38% in the group that received no prophylaxis (p < 0.01). The incidence of wound sepsis was 3% in the Augmentin group versus 13% in the control group (p < 0.01). The incidence of febrile morbidity with no identifiable cause was 8% in the Augmentin group versus 18% in the control group (p < 0.05). The duration of hospital stay was significantly shorter in the Augmentin group (p < 0.05). A single-dose of prophylactic Augmentin significantly reduced the postoperative morbidity and duration of hospital stay in women who underwent elective caesarean sections.

Adult↗
PubMed1997

Adaptation to coronary artery disease: first pilot study in the military.

To determine how a group of 29 male military patients with coronary artery disease (CAD-MIL group) have adapted physically and psychosocially, we compared results from standard questionnaires with those from 39 healthy military men (WELL-MIL group) and 27 male civilian patients with coronary artery disease (CAD-CIV group). There was no difference in the degree of severity of coronary artery disease between the two groups with the disease. The WELL-MIL group reported a higher activity level than the CAD-MIL group, which reported a higher activity level than the CAD-CIV group. Both the CAD-MIL group and WELL-MIL groups had lower levels of state anxiety compared with the CAD-CIV group, and the CAD-MIL group had a better overall psychosocial adjustment score compared with that of the CAD-CIV group. Thus, male military patients with coronary artery disease reported better physical and psychosocial adjustment to their illness than a group of male civilian patients with a similar degree of disease severity. but they were less physically active than healthy military men.

Adaptation, Psychological↗
PubMed1996

Growth patterns of the humeral and femur length in a multiethnic population.

OBJECTIVES: To study whether there are any differences in growth of the femoral and humeral length between the three major ethnic groups in Malaysia viz Malays, Chinese and Indians. The effect on fetal growth by gender of the baby and parity of the mother was also studied. METHODS: The setting was the University of Kuala Lumpur. Thirty-four Malay, 35 Chinese and 34 Indian normal pregnant middle-class women were studied longitudinally by monthly ultrasound scans for 18 to 38 weeks of gestation. The data were subjected to regression analysis; the quadratic curve was found to be the most adequate. Dummy variables were used to determine any effects by gender, parity as well as ethnicity on the length of limb growth. There was no difference in birth weights of the three ethnic groups studied, nor in gender or parity. RESULTS: There were found to be significant differences in limb lengths of the Indians (longer) when compared with the Malays and Chinese. Parity seems to affect only Indians in whom the multiparous fetuses have shorter limb lengths than the primaparous. There appears to be no effect by gender. CONCLUSION: There appear to be definite differences in growth of limb length between the different Malaysian ethnic groups and this should be taken into account when growth charts are used and when fetal weight formulas are calculated using limb lengths. The limitation of this study was that the numbers of subjects studied were small. Larger studies will be able to confirm or refute the findings.

Anthropometry↗
PubMed1996

Prenatal diagnosis of an extensive haemangioma of the fetal leg: a case report.

Extensive haemangioma with platelet consumption (Kasabach-Merritt syndrome) is rare. The lesion is usually a single cutaneous cavernous haemangioma similar to that found in our patient. Multiple superficial strawberry naevi were also seen all over the rest of the body. This condition was diagnosed antenatally in this patient with the use of colour Doppler. There is one recent report where the thrombocytopaenia was diagnosed by cordocentesis. Unfortunately the baby developed heart failure with intractable coagulopathy and died 2 days later.

Adult↗