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Biomedical subjects

B Biswas

Publications and source records attributed to B Biswas.

At least 19 recordsLinked to original sources

Epidemiology of undernutrition.

OBJECTIVE: The present study was undertaken to find out the magnitude of the problem of under nutrition among the children under 5 years of age and also to identify the important factors influencing the nutritional status of the children. METHODS: 30 cluster sampling technique had been applied in the study. A total of 600 children below five years of age were covered. Twenty under five children from each cluster were chosen for the study which was carried out during January to February '97. As per IAP criteria a total of 60.29% children were undernourished and 3.92% were severely undernourished. According to NCHS standard 46.57% & 6.86% children had weight below-2SD and -3SD respectively. RESULTS: A statistically significant relationship was found between the different age groups and nutritional status of under 5 children. Severe degree of malnutrition had highest prevalence under two years of age. The influence of variables like age, sex, religion, literacy status of parents and morbidity of the children were significantly associated with malnutrition. CONCLUSION: Practice of exclusive breast feeding, introduction of timely complementary feeding, education for maintaining personal hygiene, proper implementation of UIP immunization, periodic deworming, standard case management of diarrhoea and ARI as well as continuation of feeding during illness may reduce malnutrition of under-five children.

Age Distribution↗

Repeat whole-blood and plateletpheresis donors:unreported deferrable risks, reactive screening tests, andresponse to incentive programs.

BACKGROUND: Evaluating plateletpheresis (PPH) and repeat community whole-blood (RWB) donors' responses to donation incentive programs is essential for developing effective donor retention programs. STUDY DESIGN AND METHODS: Using data from a 1998 anonymous questionnaire sent to 92,581 US blood donors, the prevalence of unreported deferrable risks, screening test reactivity, and response to incentives were compared in RWB and PPH donors by the use of weighted chi-square tests and logistic regression analyses. RESULTS: From 52,650 respondents, 38,884 RWB and 2,028 PPH donors were identified. Levels of screening test reactivity (1%) and unreported deferrable risks (UDRs, 2-3%) were similar in RWB and PPH donors. RWB and PPH donors were strongly encouraged or discouraged by similar incentives. Of the incentives that would encourage a higher proportion of UDR-free RWB donors to return, cholesterol screening and earning a blood credit appealed to >50 percent. Similar results were obtained for cholesterol screening in PPH donors. Community service or education credits, premarital screening, and cash had limited appeal for PPH and RWB donors, respectively, and would be more likely to differentially encourage donors with a UDR to return. CONCLUSION: Incentives that were associated with the greatest donor appeal and that minimized the potential recruitment of more risky donors were identified.

Adult↗

Intrathecal midazolam for postoperative pain relief in caesarean section delivery.

Postoperative pain relief is a growing concern to an anaesthesiologist since no single analgesic is free from side-effects. Moreover, it becomes a challenge after caesarean section delivery to provide postoperative pain relief without much sedation, respiratory depression or problems like nausea, vomiting, so that early baby acceptance and care by mother is promoted. Antinociceptive effect of midazolam is well established by now and its safety is documented. This observation was made in a blind randomised study of 40 women of ASA I/II to evaluate postoperative pain relief using intrathecal midazolam in caesarean section delivery. Group A patients (n=20) received 1.5 ml of 5% lignocaine only and group B patients (n=20) received mixture of 1.5 ml 5% lignocaine with 2 mg midazolam (preservative free) through intrathecal route at L3.4 interspace; vital parameters were monitored intra-operatively and postoperatively and Apgar score of baby in 1st and 5th minute of deliverywas assessed. It was observed intrathecal midazolam produced highly significant (p<0.001) postoperative pain relief together with anti-emetic effect and tranquillity of patients of caesarean section delivery.

Adjuvants, Anesthesia↗

Cardiovascular effects of yellow oleander ingestion.

Yellow oleander (Thevetia neriifolia) is a commonly grown tree found widely in Eastern India. The seeds of yellow oleander are highly poisonous and contain three glycosides--thevetin, thevetoxin and peruvoside. Yellow oleander seed ingestion is usually with suicidal intent in Eastern India. Manifestations range from mild to potentially fatal. It has significant cardiovascular effects with varying rhythm abnormalities. Effects of yellow oleander seed ingestion (YOI) were studied in 300 patients from 1986 to 1990 at BS Medical College, Bankura. Majority i.e., 246 (82%) were females and 226 (75.33%) were young in the age group 11-20 years. Most reported for treatment 6 to 8 hours after ingestion of seeds. The number of seeds swallowed varied from half to fifteen. Two hundred and ninety-two (97.33%) ingested seeds in the crushed form; 156 (52%) were asymptomatic, 92 (30.66%) had vomiting and 36 (12%) had palpitation. In electrocardiogram (ECG), 138 (46%) revealed varying types of arrhythmias including sinus bradycardia in 68 cases (49.27%). Ischaemic changes were present in 118 cases (39.33%). Number of seeds ingested did not bear any relationship with ECG changes in YOI. All 14 cases of death were autopsied. Subendocardial and perivascular haemorrhage with focal myocardial oedema was present in all. Median hospital stay was 5 days (range 2 to 24). During discharge, 256 (85.33%) had normal ECG, 14 (4.66%) had sinus bradycardia and 16 (5.33%) demonstrated ischaemic changes.

Adolescent↗

Role of closed mitral commissurotomy for mitral restenosis.

Out of 1184 consecutive cases of rheumatic mitral stenosis treated surgically by closed mitral commissurotomy (CMC) at NRS Medical College and Hospital, Calcutta, 20 (1.68%) were mitral valve restenosis. Twelve cases (60%) were females, The median age was 32 years. Duration between the first operation and reappearance of symptoms varied with a mean of 8 years. The previous operations were digital dilatation and instrumental dilatation in 6 and 14 cases respectively. History of thromboembolism was present in 4 cases. On echocardiography, calcification of the mitral valve was present in 2 cases, left atrial clot in 4 cases, associated mild to moderate mitral regurgitation in 6 cases and mild aortic regurgitation in 4 cases. All cases presented with New York Heart Association (NYHA) III and IV symptoms. Critical stenosis (mitral valve orifice less than 0.5 cm2) was present in 12 cases. Re-do CMC was undertaken in all cases with Tubb's dilator. Median operating time was 2.5 hours. Satisfactory split was achieved in 13 cases. One patient died during surgery. Four cases having less than satisfactory split were asymptomatic on follow-up. In one case no split was possible and in another, gross mitral regurgitation was noted postoperatively. These 2 cases had to undergo open heart surgery. It is concluded that re-do CMC is a feasible and suitable alternative in mitral restenosis even in the presence of complications.

Adult↗

Studies with recombinant proteins of Ehrlichia risticii: identification of strain-specific antigen as a protective antigen.

Ehrlichia risticii is the causative agent of Potomac horse fever, an acute infectious disease of equines. To study the role of major antigens of E. risticii in protective immune response, we have expressed the genes of the 55 kDa, 51 kDa and 85/50 kDa-strain-specific antigens of the 90-12 (85 kDa antigen) and 25-D (50 kDa antigen) strains in Escherichia coli using pRSET A, B, C system (Invitrogen, San Diego, CA). Mice immunized with these purified recombinant proteins of E. risticii developed strong and specific humoral immune response. The recombinant 85 kDa antigen of the 90-12 strain protected mice against challenge infection with both E. risticii strains, whereas its homologue from the 25-D strain, the recombinant 50 kDa antigen, protected mice against only the homologous strain challenge, but not against the heterologous 90-12 strain. Sera from mice immunized with the 85- or 50-kDa antigens did not inhibit the replication of cell-free Ehrlichiae in in vitro neutralization assays. Sera from normal mice and mice immunized with other antigens caused non-specific neutralization of E. risticii. Immunoglobulin G from mice immunized with the 51 kDa protein of the 90-12 strain caused partial in vitro neutralization of both strains of E. risticii. These studies demonstrate that the 85/50-kDa-strain-specific antigen of E. risticii is involved in immunoprotection against PHF.

Animals↗

Cloning and molecular analysis of genes encoding two immunodominant antigens of Ehrlichia risticii.

Ehrlichia risticii, the causative agent of Potomac horse fever, is an obligate intracellular rickettsial organism. To understand the role of 55 and 51 kilodalton immunodominant antigens of E. risticii in strain variation, their genes from the 25-D and 90-12 strains were cloned, sequenced, and expressed in E. coli. Sequence analysis revealed that the gene for the 55 kDa antigen was present in a heat shock operon along with the gene for a ;10 kDa protein. Homology searches indicated that the 55 kDa antigen and the 10 kDa protein were homologues of E. coli GroEL and GroES proteins, respectively. There was no nucleotide sequence difference between the genes of the 55 kDa antigen, nor between the entire operons, from both strains of E. risticii. The sequence-based estimation of the sizes of the putative mature 51 kDa antigens of the 90-12 and 25-D strains were 52.7 kDa and 52.9 kDa, respectively. The 51 kDa antigens from the 90-12 and 25-D strains shared a 98% identity in their deduced amino acid sequences. The difference in some of the amino acids may be responsible for variation in their mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, where the 51 kDa antigen of the 25-D strain migrates towards a ;2 kDa lower molecular weight region. In Western blots, a 155 kDa protein that appeared to be a trimer product of the 51 kDa antigen was identified. The 55 and 51 kDa antigens were overexpressed in E. coli using a commercial expression system, pRSET A,B,C (Invitrogen Inc., San Diego, CA, U.S. A.). The purified recombinant proteins cross-reacted with antisera to E. canis and E. sennetsu.

Amino Acid Sequence↗

Molecular basis for antigenic variation of a protective strain-specific antigen of Ehrlichia risticii.

Ehrlichia risticii, the causative agent of Potomac horse fever, has recently been isolated from many vaccinated horses with typical clinical signs of the disease. The heterogeneity of the E. risticii isolates obtained from the vaccinated horses necessitates the identification of the molecular basis of strain variations to elucidate the vaccine failure and to aid in the development of an efficient vaccine against this disease. As an attempt, two major cross-reacting surface antigen genes of 50- and 85-kDa antigens, present separately in strains 25-D (isolated in 1984) and 90-12 (isolated in 1990 from a vaccinated horse), respectively, were cloned and sequenced. A comparative sequence analysis revealed differences and similarities between these two antigens with strain-specific sizes (SSA). The 2.5- and 1.6-kb genes coding for the 85- and 50-kDa proteins, respectively, contained many different tandem repeats. The identical repeat motifs were more frequent in the middle of both genes, but the numbers and positions of the repeats were altogether different in the genes. Many of these direct repeats of both genes had exact sequence homology and coded for the same amino acids. The homology of the 5'- and 3'-flanking regions of the two genes was greater than that of the regions in the central part of the genes. A comparative analysis of the deduced amino acid sequences of these two antigen genes indicated eight common domains, which were designated identical domains. Although the sequence homologies of these identical domains were the same, the positions of the domains in their respective strains were completely different. This finding might be one of the bases of antigenic variation between the strains. In addition, there were a few unique regions in both antigen genes where no sequence homology existed. These specific regions were designated unique domains. The 50-kDa protein had two such unique domains, and the 85-kDa protein had six such unique domains. The presence of such unique domains contributed to the large size variation of these SSA. The cross-reactivity of recombinant proteins confirmed the presence of conserved epitopes between these two antigens. The SSA have been determined to be apparent protective antigens of E. risticii.

Amino Acid Sequence↗

Association of deficiency in antibody response to vaccine and heterogeneity of Ehrlichia risticii strains with Potomac horse fever vaccine failure in horses.

Ehrlichia risticii is the causative agent of Potomac horse fever (PHF), which continues to be an important disease of horses. Commercial inactivated whole-cell vaccines are regularly used for immunization of horses against the disease. However, PHF is occurring in large numbers of horses in spite of vaccination. In a limited study, 43 confirmed cases of PHF occurred between the 1994 and 1996 seasons; of these, 38 (89%) were in horses that had been vaccinated for the respective season, thereby clearly indicating vaccine failure. A field study of horses vaccinated with two PHF vaccines indicated a poor antibody response, as determined by immunofluorescence assay (IFA) titers. In a majority of horses, the final antibody titer ranged between 40 and 1,280, in spite of repeated vaccinations. None of the vaccinated horses developed in vitro neutralizing antibody in their sera. Similarly, one horse experimentally vaccinated three times with one of the vaccines showed a poor antibody response, with final IFA titers between 80 and 160. The horse did not develop in vitro neutralizing antibody or antibody against the 50/85-kDa strain-specific antigen (SSA), which is the protective antigen of the original strain, 25-D, and the variant strain of our laboratory, strain 90-12. Upon challenge infection with the 90-12 strain, the horse showed clinical signs of the disease. The horse developed neutralizing antibody and antibody to the 50/85-kDa SSA following the infection. Studies of the new E. risticii isolates from the field cases indicated that they were heterogeneous among themselves and showed differences from the 25-D and 90-12 strains as determined by IFA reactivity pattern, DNA amplification finger printing profile, and in vitro neutralization activity. Most importantly, the molecular sizes of the SSA of these isolates varied, ranging from 48 to 85 kDa. These studies suggest that the deficiency in the antibody response to the PHF vaccines and the heterogeneity of E. risticii isolates may be associated with the vaccine failure.

Animals↗

Long-circulating bacteriophage as antibacterial agents.

The increased prevalence of multidrug-resistant bacterial pathogens motivated us to attempt to enhance the therapeutic efficacy of bacteriophages. The therapeutic application of phages as antibacterial agents was impeded by several factors: (i) the failure to recognize the relatively narrow host range of phages; (ii) the presence of toxins in crude phage lysates; and (iii) a lack of appreciation for the capacity of mammalian host defense systems, particularly the organs of the reticuloendothelial system, to remove phage particles from the circulatory system. In our studies involving bacteremic mice, the problem of the narrow host range of phage was dealt with by using selected bacterial strains and virulent phage specific for them. Toxin levels were diminished by purifying phage preparations. To reduce phage elimination by the host defense system, we developed a serial-passage technique in mice to select for phage mutants able to remain in the circulatory system for longer periods of time. By this approach we isolated long-circulating mutants of Escherichia coli phage lambda and of Salmonella typhimurium phage P22. We demonstrated that the long-circulating lambda mutants also have greater capability as antibacterial agents than the corresponding parental strain in animals infected with lethal doses of bacteria. Comparison of the parental and mutant lambda capsid proteins revealed that the relevant mutation altered the major phage head protein E. The use of toxin-free, bacteria-specific phage strains, combined with the serial-passage technique, may provide insights for developing phage into therapeutically effective antibacterial agents.

Animals↗

Purification of acid phosphatase I from germinating seeds of Vigna sinensis.

Acid phosphatase I (AP-I) is the major isoform of Vigna acid phosphatase. It is constitutively expressed in seed cotyledons during germination. AP-I was separated from other isoforms and purified to homogeneity by three simple purification steps; (NH4)2SO4 precipitation, and phosphocellulose and DEAE-cellulose column chromatography. The activity of AP-I was not affected by 1 mM Mg2+, Mn2+, Ca2+, Co2+ or Pb2+, but severely inhibited by 1 mM Cu2+, Fe3+, Hg2+, Mo6+ or Zn2+. AP-I has both phosphatase and pyrophosphatase activities, and is highly stable even at 50 degrees.

Acid Phosphatase↗

Hydroalcoholic human placental extract: skin pigmenting activity and gross chemical composition.

BACKGROUND: Vitiligo is a pigmentary disorder of the skin of unknown etiology. It is thought to be of autoimmune origin after demonstration of antibody-mediated destruction of melanocytes. Photochemotherapeutic PUVA therapy is widely used in vitiligo with about 33% success. Aqueous or hydroalcoholic extracts of human placenta of ill-defined composition have also been used therapeutically for vitiligo. A hydroalcoholic human placental extract has been developed by us with pigmenting activity based on experimental therapies. Its chemical analysis was the primary objective of this study. METHODS: For the guinea pig experiment, 20 drops of the extract or vehicle (60% alcohol) as control was topically applied around the nipples covering the areola zones of male immature white guinea pigs (wt. 175-250 g) daily for 60 days with 15 minutes infrared (IR) exposure used for vascular dilatation and enhancement of the absorption of the extract. Standard methods have been followed for all chemical analyses. RESULTS: The guinea pig experiment showed clear pigmentation and hypertrophy of the experimental nipples to varying degrees. Chemical analysis of the extract revealed the presence of small-molecular-weight proteins/peptides, lipids (including glycosphingolipids), carbohydrates, sialic acids, cholesterol, triglycerides, high density lipoproteins (HDL), and others, including amino acids, nucleotides, carotenes, vitamins, etc. CONCLUSION: Glycosphingolipids, known modulators of B and T cells, were reported capable of inducing adhesion, spreading, and motility of melanoma. It is present in the extract and, therefore, may lead to skin pigmentation through induction of melanocytes. Endothelin, a 21-amino acid peptide, detected in human placenta and possibly extractable by our process, has been reported to be indispensable for melanocyte growth.

Absorption↗