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Biomedical subjects

P Raj

Publications and source records attributed to P Raj.

At least 37 records · Page 2Linked to original sources
PubMed1994

Synthesis and biological studies on some organo-tin and lead halo and mixed halo-pseudohalo anionic complexes.

Some new anionic complexes of organo-tin(IV) and lead (IV) isolated in combination of tetraorgano-ammonium phosphonium and stibonium cation(s). L[R4-nMXnY] and L2[R2MX2Y2], where R = C2H5, C4H9 or C6H5; M = Sn or Pb; X = Y = Cl = Br, I, N3, NCS; n = 1, 2 and L = R4M1 (M1 = N, P, Sb), whose structures were confirmed by correct elemental analyses, molar conductance values, van't Hoff factor and IR spectral studies, were synthesized and evaluated for anti-convulsant activity in vivo and antiviral and antibacterial activity in vitro. A few of them exhibited promising activity. In addition, the toxicity (ALD50) and effects on the central nervous system of these complexes have been studied in mice.

Animals↗
PubMed1992

Comparisons of rotavirus VP7-typing monoclonal antibodies by competition binding assay.

Three sets of neutralizing monoclonal antibodies (MAbs) used to type the outer capsid protein VP7 of four group A rotavirus serotypes (1 through 4) were compared in competition immunoassays. Reciprocal competition was observed for each of the VP7 type 2-, 3-, and 4-specific MAbs. The VP7 type 1 MAbs exhibited variable competition patterns with other VP7 type 1 MAbs. MAb RV4:3, which has been used to recognize antigenic variants within VP7 type 1 strains, showed reciprocal competition with the four VP7 type 3 MAbs (RV3:1, YO-1E2, 4F8, and 159) using a VP7 type 3 virus (SA11) as antigen. MAb 2C9, also prepared against VP7 type 1, reacted with VP7 type 3 strains and competed with a VP7 type 3 MAb, 159, using RRV as antigen. Use of the different sets of VP7 type-specific MAbs in the enzyme-linked immunosorbent assay permitted the recognition of six antigenic variants within VP7 types 1, 2, and 3 among specimens whose VP7 type could not be determined previously with only one set of typing MAbs. These results demonstrate differences of typing ability among these VP7-specific MAbs and emphasize the need to improve the sensitivity of typing systems by incorporating panels of MAbs reacting with several neutralizing epitopes.

Antibodies, Monoclonal↗
PubMed1992

Characterization of serum antibody responses to natural rotavirus infections in children by VP7-specific epitope-blocking assays.

Knowledge of the immune response to rotavirus is crucial for vaccine development. We compared an epitope-blocking assay (EBA) that uses VP7-specific monoclonal antibodies with neutralization assays (NAs) with polyclonal antisera for detecting serum antibody responses after natural rotavirus infection in children. Twenty-six serum pairs from children living in an orphanage with and without symptoms during two rotavirus outbreaks were evaluated for VP7 type 1-, 2-, 3-, and 4-specific antibody responses. In the first outbreak, which was caused by a VP7 type 3 strain, homotypic antibody responses were detected in 11 of 11 symptomatic children by NA and in 10 of 11 symptomatic children by EBA. Heterotypic antibody responses were detected more frequently (12 of 15 children) by NA than by EBA, and the heterotypic epitope-blocking antibody responses occurred in children older than 14 months of age. Antibody responses in asymptomatic children were more commonly detected by EBA than by NA. EBA results from the sera of children in the second outbreak indicated that it was caused by VP7 type 4, whereas NA results suggested it was caused by VP7 type 3. Our results confirm that EBA is a sensitive and specific method for determining VP7 type-specific immune responses after natural rotavirus infections.

Antibodies, Viral↗
PubMed1990

Rotavirus-specific antibody response in saliva of infants with rotavirus diarrhea.

The reliability of saliva as an indicator of rotavirus infection was assessed among 15 infants (3-12 months) with rotaviral and 15 with nonrotaviral diarrhea. Paired salivary samples collected during acute and convalescent phases were tested for rotavirus-specific IgA and IgM by an ELISA. The sensitivity of IgA or IgM alone to predict infection was 53.3% and 46.6%, respectively; used in conjunction, the sensitivity rose to 80%. It seems that infants with rotaviral diarrhea mount mucosal antibody responses as reflected in their saliva; possibly salivary antibodies could be used to evaluate vaccine "take" in rotavirus vaccine trials.

Antibodies, Viral↗
PubMed1990

Salmonella typhimurium-associated severe protracted diarrhea in infants and young children.

Eleven (13.8%) children (4-14 months; mean of 7.8 +/- 3.6 months) presenting with protracted diarrhea (duration greater than 21 days) and weight loss had associated infection with Salmonella typhimurium. All had documented weight loss of 16-25% and progressive clinical deterioration. On admission, they had high purging rates (greater than 4 ml/kg/h), hyponatremia (5/11), mucosal injury, and malabsorption as measured by 1 h blood D-xylose, fecal alpha 1-antitrypsin, and oral fat tolerance test. Diarrhea was secretory in 8 of 11 and fecal sodium was high (54-142 mEq/L; mean of 102 +/- 27 mEq/L). The organism showed multiple drug resistance. All patients received antibiotics (amikacin and nalidixic acid/norfloxacin) for 10-14 days, which was followed by rapid improvement in clinical status and absorption studies. The two youngest patients died. Due to ethical reasons, an untreated control group was not included. Use of appropriate antibiotics may benefit children with S. typhimurium-associated severe protracted diarrhea and rapid progressive weight loss.

Amikacin↗
PubMed1990

Human enterocyte adhesion of enteroadherent Escherichia coli.

Esch. coli strains manifesting localised (17), diffuse (8) or aggregative (17) phenotypes of adherence to HEp-2 cells were tested for their ability to adhere to human enterocytes isolated from duodenal biopsies of adult volunteers to obtain further evidence of their enteropathogenecity. Esch. coli strains H10407+; CFAI+ and LT+ STp+ STh+, F 294 B; a localised adherent strain positive with entero-adherent factor probe reported previously to attach to small intestinal enterocytes and F 582 C; LT- STp+ STh+ were the positive controls: H10407P (CFAI- mutant of H10407+) and K12 served as negative control strains. Adherence of variable degree was seen with 35.3 per cent of enteroaggregative Esch. coli (EAggEc) and with 58.8 per cent of enteroadherent Esch. coli localised (EAEC-L); EAEC-diffuse (EAEC-D) did not adhere to the human enterocytes. The possibility that EAgg EC and diffuse phenotypes may adhere better to lower small intestine or the large intestine, needs to be investigated.

Adult↗
PubMed1989

Enteroaggregative Escherichia coli associated with persistent diarrhea in a cohort of rural children in India.

A cohort of 452 rural children was followed longitudinally for 13 mo to ascertain the role of HEp-2 cell adherent Escherichia coli and other pathogens in causing acute (less than or equal to 14 d) and persistent (greater than 14 d) diarrhea. Aeromonas, Campylobacter jejuni, E. coli manifesting localized adherence to HEp-2 cells and enterotoxigenic E. coli were significantly associated with acute diarrhea. E. coli strains that exhibit aggregative adherence, so-called enteroaggregative E. coli, a newly-described category of diarrheagenic E. coli distinct from enterotoxigenic, enteroinvasive, enterohemorrhagic, and enteropathogenic E. coli, were found significantly more often in patients with persistent diarrhea (29.5%) than with acute diarrhea (12.8%) (P = .0052) or controls (9.9%) (P = .0006).

Acute Disease↗
PubMed1989

Enteroaggregative Escherichia coli and Salmonella associated with nondysenteric persistent diarrhea.

A hospital-based case-control study including 92 children with diarrhea for longer than 14 days and 92 controls without gastrointestinal symptoms was performed to describe the association between the excretion of enteric pathogens and persistent diarrhea. In patients the most frequently isolated stool pathogens were enteroaggregative Escherichia coli (19.6%), nontyphoidal Salmonella spp. (17.4%), E. coli with diffuse adherence pattern (7.6%), G. lamblia (7.6%) and enterotoxigenic E. coli (5.4%). The excretion rates in patients were significantly greater than in controls only for nontyphoidal Salmonella spp. (P = 0.0006) and enteroaggregative E. coli (P = 0.016).

Diarrhea, Infantile↗
PubMed1989

Increased faecal alpha-1-antitrypsin excretion in children with persistent diarrhoea associated with enteric pathogens.

The random faecal alpha-1-antitrypsin (AT) excretion (mg/g dry weight of stool) was measured in 30 infants and children (mean age 10.8 +/- 8 mo.) with protracted diarrhoea (duration greater than or equal to 21 days) and failure to thrive and 27 normally nourished children (mean age 13 +/- 4.5 mo.) without any gastrointestinal symptoms in the preceding 12 weeks. The associated factors in patients with protracted diarrhoea and their mean faecal AT during active disease and 3-4 weeks after recovery were as follows: Enteropathogenic E. coli 5 (7.9 +/- 5.5; 3.2 +/- 0.6), Giardia lamblia 4 (3.9 +/- 1.8; 2.5 +/- 0.7), Salmonella typhimurium 3 (4.0 +/- 0.2; 3.8 +/- 0), secondary carbohydrate intolerance 11 (2.5 +/- 0.9; 2.4 +/- 0.8), and others 7 (3.4 +/- 0.7; 3.0 +/- 0.5), respectively. Of all the patients with protracted diarrhoea the mean AT in the E. coli, Giardia and Salmonella groups were significantly higher than the mean in the control group (2.1 +/- 0.8) and following treatment and recovery the values were comparable to that in the controls. All the 6 patients with very high faecal AT (greater than mean + 3 SD of controls) were associated with an enteric pathogen.

Diarrhea, Infantile↗
PubMed1989

Electrophoretic study of the genome of human rotavirus in rural Indian community.

A rural cohort of 507 children, less than 3 yr of age was kept under weekly surveillance for 12 months, for morbidity due to diarrhoea. Stool specimens for rotavirus detection were obtained in 346 of the 360 diarrheal episodes occurring in 354 children and in 211 children without diarrhoeal symptoms. Rotavirus was detected by an ELISA test in 4 per cent of children with diarrhoea and 6.6 per cent of control subjects. Viral genome RNA was extracted by phenol chloroform method from all the positive samples and analysed by polyacrylamide gel electrophoresis followed by silver staining. All the strains isolated, exhibited the same electropherotype with a 'long' RNA migration pattern. This result contrasts with the genomic variability amongst rotavirus strains usually observed in different settings.

Child, Preschool↗
PubMed1989

Evaluation of a new latex agglutination kit for detection of human rotavirus in faecal specimens.

A commercial latex agglutination (LA) test was compared with ELISA and direct electron microscopy (EM) for detection of rotavirus antigen in 93 stool specimens obtained from as many children with acute gastroenteritis. Seventy one specimens (76.3%) were either positive or negative with all the three techniques, while 22 (23.7%) gave contradictory results. Only 1 sample was positive by LA test but not with ELISA or EM. The sensitivity of LA test and EM was 62.5 per cent (30 of 48) and 75 per cent (36 of 48); the corresponding specificity being 97.7 per cent (44 of 45) and 100 per cent (45 of 45) respectively. ELISA was more sensitive than the LA test and EM for detection of rotavirus antigen. LA test which is highly specific and a rapid method, may be useful in certain situations but its low sensitivity makes it unsuitable for use in routine clinical practice.

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

Efficacy of nalidixic acid in the treatment of acute bloody diarrhea.

Of sixty four children (mean age 20.1 +/- 1.2 mo) with acute bloody diarrhea and high fever, 47 had infection with non-typhoidal Salmonella (NTS) (20), Shigella (15) and enteropathogenic E. coli (EPEC) (12) and were treated with nalidixic acid (NA). The mean duration (h) of presence of macroscopic blood in the stool following institution of treatment was significantly shorter (p less than 0.05) in those with EPEC (11.5 +/- 4.9) as compared to NTS (30.4 +/- 15.4) or Shigella groups (22.9 +/- 15.6). The number of children having less than or equal to 50% reduction in stool frequency within 72 h was: NTS (17); Shigella (14); EPEC (10). Negative stool cultures on day 5 were obtained in all patients with Shigella and EPEC and 16 (80%) of those with NTS. Two patients with NTS and one with EPEC failed to respond to NA.

Acute Disease↗
PubMed1989

Descriptive epidemiology of persistent diarrhoea among young children in rural northern India.

In order to determine the descriptive epidemiology of persistent diarrhoea in rural northern India, a cohort of 963 children aged 0-71 months was followed prospectively for 12 months through weekly household visits. The incidence of persistent diarrhoea was 6.3 per 100 child-years among those aged 0-71 months, and was highest (31 per 100 child-years) among those aged 0-11 months. There were no significant sex-related differences in the incidence of the disease, and the overall seasonal distribution of acute and persistent diarrhoea was similar. The persistence of diarrhoeal symptoms was significantly correlated with a higher initial mean stool frequency (P less than 0.01) and passage of gross blood with stools (P less than 0.001). Persistent diarrhoea was an important problem among children during the first 2 years of life. Established enteric pathogens were isolated during the initial illness in 46.4% of persistent and 55.4% of acute episodes. Pathogens isolated during persistent episodes included enterotoxigenic Escherichia coli (ETEC 9.3%), Salmonella spp. (4.7%), as well as campylobacter (4.7%), Shigella spp. (2.3%), Entamoeba histolytica (2.3%), and rotavirus (2.3%). Similar proportions of these pathogens were isolated also during episodes of acute diarrhoea. Multiple pathogens were isolated in 7% of the persistent and 5% of the acute episodes. E. coli that manifested aggregative adherence (EAEC-A) was more common (34.9% versus 12.3%) in persistent than acute episodes (P less than 0.01), and initial faecal excretion of EAEC-A was significantly associated with the persistence of a diarrhoeal episode.

Child↗
PubMed1989

Quantitation and properties of fecal and upper small intestinal aerobic microflora in infants and young children with persistent diarrhea.

The duodenal juice and fecal aerobic microflora was investigated in 54 patients with persistent diarrhea (age less than or equal to 2 years). The duodenal aspirates yielded increased aerobic bacteria (greater than 10(5) organisms/ml) in 28 (51.9%) of the patients. Established enteric pathogens were isolated from the duodenal aspirates of 12 (22.2%) of the 54 patients, viz., enteroadherent Escherichia coli (EAEC) (5), enterotoxigenic E. coli (ETEC) (3), enteropathogenic E. coli (EPEC) (1), nontyphoidal Salmonella (1), and Giardia lamblia (2). The total aerobic bacterial count was greater than 10(5) in all 12 patients positive for specific pathogens apart from one case in whom E. coli showing diffuse adherence to HEp-2 cells were identified. Among the remaining 42 specific pathogen-negative patients, 19 (45.2%) also had greater than 10(5) aerobic organisms/ml in the small bowel. Eight strains of Klebsiella from four of the patients were negative for enterotoxin production in a rabbit ileal loop assay and for adherence to HEp-2 cells. In contrast, 28/54 (51.9%) of the same patients had known enteric pathogens in their stools, viz., nontyphoidal Salmonella (8 or 14.8%), Shigella (2 or 3.7%), Campylobacter (1 or 1.9%), ETEC (4 or 7.4%), EPEC (2 or 3.7%), EAEC (7 or 13.0%), and G. lamblia and Entameba histolytica (3 or 5.6%). Further search for potential virulence factors among aerobic bacteria colonizing the upper small intestine in persistent diarrhea is warranted.

Aerobiosis↗
PubMed1988

Role of enteric adenoviruses and rotaviruses in mild and severe acute enteritis.

The role of enteric-type adenoviruses and rotaviruses in mild and severe acute gastroenteritis was investigated among children younger than 5 years of age seeking treatment at an urban hospital (UH) and at a rural health center (RHC) in India. There were 330 children at the UH and 340 at the RHC; 319 and 315 age matched nondiarrheal children served as controls for the respective groups. Rotavirus was detected in 15.2% of 330 cases and 1.9% of 319 controls at the UH (P less than 0.001) and in 16.5% of 340 cases and 2.9% of 315 controls at the RHC (P less than 0.001). RV excretion was 3- to 5-fold more common in severe compared with mild diarrhea at the UH and at the RHC (P less than 0.001). The detection rate for enteric-type adenoviruses was similar in patients and controls, respectively, at the UH (0.9%; 2.5%) and RHC (3.8%; 2.5%). At the RHC adenovirus types other than 40 and 41 were excreted by 8.8% of the patients and by only 1.0% of the controls (P less than 0.001). It is possible that the diarrheagenic role of adenoviruses may not be restricted to types 40 and 41.

Adenoviruses, Human↗
PubMed1988

Cloned polynucleotide and synthetic oligonucleotide probes used in colony hybridization are equally efficient in the identification of enterotoxigenic Escherichia coli.

Restriction endonuclease-generated polynucleotide and synthetically produced oligonucleotide gene probes used in colony hybridization assays proved to be efficient for the detection and differentiation of enterotoxigenic Escherichia coli. To compare their relative efficiencies, these two sets of probes were radiolabeled with 32P and were applied to 74 strains of E. coli with known enterotoxin profiles and to 156 previously unexamined E. coli isolates. The enterotoxigenic bacteria Vibrio cholerae O1, Vibrio cholerae non-O1 (NAG), Yersinia enterocolitica, and E. coli harboring the plasmid vectors of the polynucleotide gene probes were examined for further evaluation of probe specificity. The two classes of probes showed a perfect concordance in their specific detection and differentiation of enterotoxigenic E. coli. In the analysis of six strains, the signal strength on autoradiography after hybridization with oligonucleotides was weaker than that obtained after hybridization with polynucleotide probes. The probes did not hybridize with DNA from V. cholerae O1, V. cholerae non-O1 (NAG), or Y. enterocolitica. The strains of E. coli harboring the plasmid vectors of the polynucleotide gene probes were, likewise, negative in the hybridization assays.

Base Sequence↗