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Biomedical subjects

P Seth

Publications and source records attributed to P Seth.

At least 235 records · Page 13Linked to original sources

Prevalence of rubella virus and cytomegalovirus infections in suspected cases of congenital infections.

Although rubella virus and cytomegalovirus (CMV) are important causes of congenital infections, information on their prevalence in our country is scarce. We studied a total of 249 infants suspected of having congenital infections from January 1988 to September 1989. Serum samples of these infants were tested for rubella and cytomegalovirus specific IgM antibodies by mucapture ELISA. Thirty (12%) infants were positive for rubella IgM antibody, and 50 (20%) had CMV specific IgM antibody. In the group presenting with hepatosplenomegaly (n = 56) rubella and CMV specific IgM antibodies were detected in 1 (1.7%) and 25 (44.6%) infants respectively. In the group presenting with congenital malformations (n = 90), 23 (25.5%) were positive for rubella, and only 9 (10%) had CMV IgM antibodies. Of the infants presenting with mental retardation (n = 39), only CMV infection was detected in 3 (7.7%) infants, whereas amongst the group showing intrauterine growth retardation (n = 16), 5 (31.25%) had CMV specific IgM antibodies and 2 (12.5%) had rubella specific IgM antibodies. In the miscellaneous group (n = 48), 4 (8.3%) and 8 (16.6%) infants had rubella and CMV IgM antibodies respectively. CMV infection was prevalent in a significantly higher number of children with hepatosplenomegaly than rubella while in infants with congenital malformations a significantly higher number had rubella infection. It is concluded that rubella and CMV infections are commonly seen in children with intrauterine infections in our population.

Antibodies, Viral↗

Dengue haemorrhagic fever in children in the 1996 Delhi epidemic.

An epidemic of dengue haemorrhagic fever (DHF) occurred in Delhi in 1996. A total of 240 children between the age of 4 months to 13 years of either sex, admitted in one hospital, were evaluated. Two hundred and sixteen (90%) children were from Delhi. A clinical diagnosis of dengue fever (DF) was made in 25 (10%), dengue fever with unusual bleeding (DFB) in 22 (9%), DHF in 80 (33%) and dengue shock syndrome (DSS) in 113 (47%) of the children strictly according to the WHO classification. The age peaked at 8 years. There was no association between various grades of severity of illness and age-groups though girls suffered from more severe illness. No association between severity of malnutrition and severity of illness was observed. Tourniquet test was positive in 40% with DF, 18% with DFB, 62% with DHF and 64% with DSS. In DSS haematemesis was present in 55 (49%), epistaxis in 39 (35%), melaena in 27 (24%) and ecchymosis in 34 (30%) patients. Children diagnosed as DFB had haematemesis and epistaxis in 12 (55%) and 10 (45%) respectively. Intravenous fluid requirement was clearly less in DFB patients than in DHF/DSS patients. Unusual clinical features in the form of jaundice were present in 7 (6%), hepatic encephalopathy in 6 (5%) and dengue encephalopathy in 6 (5%) patients. Dengue 2 virus was isolated from 10 of the 50 patients for whom viral culture was done on C6/36 clone of Aedes albopictus cell line. Eighteen patients suffering from DSS died giving an overall case fatality of 7.5%. The mortality rate in DHF/DSS was 9.3%. It is further suggested that DFB is a distinct entity. Most patients could be classified by the WHO classification if a retrospective packed cell volume was used to assess haemoconcentration. We suggest that development of area-specific criteria for diagnosis and management is desirable.

Antibodies, Viral↗

The evaluation of adenoviral p53-mediated bystander effect in gene therapy of cancer.

Because many tumors have mutated p53, one potential strategy proposed for cancer gene therapy is the introduction of the wild-type p53 gene into tumor cells. One puzzling aspect of this approach is that currently available gene transfer protocols result in a small percentage of tumor cells being transduced in vivo, thus implicating a "bystander effect" to achieve therapeutic efficacy. Because bystander effects in the context of p53-mediated gene therapy have not been well characterized, we evaluated the role of in vitro and in vivo bystander effects of adenovirally delivered p53 (AdWTp53). Using human tumor cell lines that did not express p53 protein but were infectible with adenovirus and showed sensitivity to p53-mediated apoptosis, we were unable to demonstrate an AdWTp53-mediated in vitro bystander effect, despite seeing strong bystander effects when cells were infected with an adenovirus containing the suicide gene herpes simplex virus thymidine kinase and treated with ganciclovir. In contrast, in vivo flank mixing studies using one of these cell lines showed a weak but significant p53-mediated bystander effect (a 40% inhibition of tumor growth). This bystander effect translated into a small survival advantage in an established intraperitoneal tumor model when tumor burden was low at the time of viral instillation. The survival advantage was lost, however, when tumor burden was increased. This study indicates that treatment of human tumors using AdWTp53 may be possible; however, because of the weak bystander effect in vivo, effective treatment will likely require a large percentage of tumor cells to be transduced.

Adenoviridae↗