Search PubMed⌕ Search

Biomedical subjects

P Sarkar

Publications and source records attributed to P Sarkar.

At least 37 records · Page 2Linked to original sources
PubMed1997

Humoral immune response of chicks to different clinical isolates of avian adenovirus type-1.

The humoral immune response of 7-day-old chicks to different strains of avian adenovirus (AAV) type-1 was determined by counter immunoelectrophoresis (CIE) and enzyme-linked immunosorbent assay (ELISA). In CIE antibody was detected 14 days post-infection (PI) whereas in ELISA antibody was detected 7 days PI. The ELISA titre reached its peak at 21 days PI in all groups. The pattern of immune response among the groups was found to be similar.

Adenoviridae Infections↗
PubMed1997

Structural polypeptides of different clinical strains of avian adenovirus type-1.

The polypeptides of two liver strains, two ovarian strains and one standard strain of avian adenovirus-1 (AAV-1) were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot using polyclonal antibodies to all the strains and isoelectric focusing (IEF). All the strains had 11 polypeptides and molecular weight varied between 9 and 100 kDa. The polypeptide pattern was similar in all the strains as revealed by SDS-PAGE and Western blot. However, some differences among the strains on the basis of isoelectric point of polypeptide were observed by IEF.

Antibodies, Viral↗
PubMed1994

Loss of RT6 message and most circulating T cells after thymectomy of diabetes prone BB rats.

T cells expressing the RT6 surface alloantigen perform important immunoregulatory functions in the rat. Diabetes prone (DP) BB rats are deficient in circulating RT6+ T cells and develop spontaneous autoimmune diabetes mellitus. Transfusions leading to engraftment of RT6+ T cells prevent the disease. Coisogenic diabetes resistant (DR) BB rats do circulate RT6+ T cells and are free of disease. We investigated the basis for the deficiency of RT6+ T cells in the DP-BB rat and made the following observations. 1. Thymectomy causes the rapid loss of most peripheral T cells in the DP-BB rat. 2. Concomitant with the loss of T cells is the total loss of mRNA encoding RT6. 3. In contrast to the effects observed in peripheral lymphoid tissues, thymectomy does not lead to a detectable loss in RT6+ protein found in the small intestine. We conclude that the deficiency of RT6+ peripheral T cells in the DP-BB rat is due either to their short life span or to their reduced proliferative capacity following release from the thymus.

ADP Ribose Transferases↗
PubMed1994

An exploratory evaluation of ECT in haloperidol-treated DSM-IIIR schizophreniform disorder.

In a double-blind, prospective study, 30 consecutive treatment-naive adult men with first-onset psychosis and DSM-IIIR provisional schizophreniform disorder (without good prognostic features) were randomized into true electroconvulsive therapy (ECT) and sham ECT groups. Both groups received haloperidol in a fixed dose of 15 mg at night. The ECT schedule comprised six bilateral, sinusoidal wave treatments administered on alternate days, thrice a week. Weekly ratings for the first 6 weeks showed an absence of significant difference between the groups in the number of patients responding and in the rate of attenuation of psychosis; severity of depression, while less in the true ECT group after the first 3 weeks, did not differ between the groups at any subsequent time point. Clinical ratings were repeated at 6 months, and social functioning was assessed; again, no group differences emerged. It is concluded that ECT does not meaningfully improve response in unselected schizophreniform disorder that is treated with an adequate dose of neuroleptic.

Adolescent↗
PubMed1993

An RT6a gene is transcribed and translated in lymphopenic diabetes-prone BB rats.

T-cells expressing the RT6 surface alloantigen appear to perform important immunoregulatory functions in the rat. Diabetes-prone BB rats lack circulating RT6+ T-cells and spontaneously develop autoimmune diabetes mellitus and thyroiditis. The coisogenic diabetes-resistant BB rat does circulate RT6+ T-cells and is free of disease. Transfusions leading to engraftment of RT6+ T-cells prevent both diabetes and thyroiditis in the diabetes-prone rat. To investigate the absence of this subset in the lymphopenic BB rat, we used both molecular and biochemical procedures and made the following observations: 1) an mRNA encoding RT6 protein is present in diabetes-prone spleen cells; 2) nucleotide sequencing of this transcript reveals an intact coding sequence for the RT6.1 alloantigen; 3) sensitive chemiluminescent assay of diabetes-prone lymph node cell detergent extracts shows that diabetes-prone RT6 mRNA is translated in vivo; 4) quantitatively, diabetes-prone lymph node cells express < or = 10% of the RT6.1 protein found on similar numbers of diabetes-resistant BB cells; and 5) finally, we obtained evidence of an intact phosphatidylinositol linkage of the molecule to the cell surface and successfully immunoprecipitated the phosphatidylinositol-linked protein with DS4.23 monoclonal antibody, indicating that the RT6.1 antigen is correctly processed and folded in diabetes-prone lymph node cells. We conclude that the near total absence of RT6+ T-cells in the diabetes-prone BB rat is unlikely to be because of a defect in RT6 gene expression per se. Defects in RT6 gene regulation or other cellular defects leading to premature cell death in the T-cell lineage, alone or in combination, may instead be responsible.

ADP Ribose Transferases↗
PubMed1992

The effect of music on ketamine induced emergence phenomena.

The purpose of this investigation was to assess the influence of music on emergence phenomena after ketamine anaesthesia. Fifty ASA 1 patients undergoing minor gynaecological procedures were randomly divided into two equal groups. Patients in the treated group were played music of their choice through headphones from 5 min before induction of anaesthesia to 15 min postoperatively. Although the incidence of emergence phenomena was similar in both groups the effects tended to be more pleasant and acceptable in those to whom music was played. The majority of patients in the study group (80%) expressed their willingness to have a similar anaesthetic in the future compared to 52% in the control group (p less than 0.05).

Adult↗
PubMed1992

Detection of rabies virus in different tissues of experimentally infected mice at preclinical and postclinical stages of the disease.

Rabies fixed virus (CVS) was passaged 10 times in mice by intramuscular (im) route followed by experimental inoculation of the titrated virus in 4 groups of mice with the dose of 0.1 ml of 1000 mouse (LD50 0.03 ml) using intracerebral (ic), intravenous (iv), intramuscular (im), intraocular (io), and intranasal (in) routes respectively. No marked variation in clinical signs due to variation of routes could be detected. Involvement of brain with io route could be detected even in preclinical stage. Although the virus could be detected in the postclinical stage in all the tissues under study (brain, skin, salivary gland and corneal impression), with io and ic routes spread of the virus was observed in comparatively higher concentrations.

Animals↗
PubMed1989

Developmentally regulated male-specific transfactor(s) enable in vitro transcription of a cloned alpha 2u-globulin gene.

Selected members of the rat alpha 2u-globulin gene family are expressed in several tissues, manifesting characteristic developmental and endocrine transcriptional control. Studies are now underway to identify the responsible cis sequences and transacting factors. We recently reported that the cloned rat alpha 2u-globulin 207 gene manifests tissue-specific androgen-dependent expression; it is expressed in livers of male, but not female, transgenic mice. In the present study a portion of this gene (-639 to +1395) is used as an in vitro template in the presence of nuclear extracts derived from hepatic nuclei of prepubescent and mature male and female rats. alpha-Amanitin-sensitive in vitro transcription of the alpha 2u 207 gene by extracts derived from mature male rats is highly active and is at least 13 times as rapid as that with preparations from mature female or immature animals. In contrast, the rate of transcription of a control template, the adenoviral late promoter, is the same with all of these nuclear extracts. S1 nuclease analysis and the size of the transcript indicate that transcription is initiated in vitro at the same site as it is in vivo and that it continues to the 3' terminus of the alpha 2u-globulin template. Thus, cis sequences are present in this gene fragment which are controlled by developmentally regulated male transacting factors, enabling selective transcription of this alpha 2u-globulin gene. Mixing experiments indicate that this transcriptional control is positive.

Alpha-Globulins↗
PubMed1985

Nucleotide sequence of a major class-III phage-T3 RNA-polymerase promoter located at 98.0% of phage-T3 genetic map.

The entire nucleotide sequence of a 409-bp HincII fragment, located within the MboI-E fragment on bacteriophage T3 DNA and containing a major class-III T3 RNA polymerase promoter positioned at 98% on the standard T3 genetic map, has been determined. Alignment of this class-III promoter with previously determined T3 RNA polymerase promoters, with start points of transcription (+1) in register, indicates high degree of sequence conservation between position -16 to +6 among all T3 RNA polymerase promoters. The conserved portion of the (-) strand sequence is 5'-A-TA-T-AT-A-C-C-C-T-C-A-C-T-A-A-A-G-G-G-A---3'. This fragment also contains an open reading frame (ORF) with a translational start codon located at position +146 which is preceded by a potential ribosome binding site (RBS). There is more than 70% amino acid-sequence homology between the deduced sequences of the -NH2 terminal region of this putative T3 phage protein and the corresponding protein coded by bacteriophage T7 (protein of T7 gene 19.5).

Base Sequence↗
PubMed1984

Locations and nucleotide sequences of three major class III promoters for bacteriophage T3 RNA polymerase on T3 DNA.

The DNA sequences of three major class III T3 RNA polymerase promoters located at 45.0, 55.0, and 64.8% on the standard T3 genetic map have been determined. The precise RNA initiation sites were also determined by 5'-terminal RNA sequence analysis of the transcripts synthesized from the promoter-containing DNA fragments. Alignment of these three class III promoters and a previously determined T3 RNA polymerase promoter at 1.05% on T3 genetic map, with start points of transcription (+1) in register, indicates a high degree of sequence conservation among the four T3 RNA polymerase promoters. The sequences are identical between positions -12 and +4 and are uniformly A-T between -12 and -17. The conserved portion of the (-) strand sequence is 5' (sequence in text) Upstream from -17 and downstream from +4 the sequences diverge. Comparison of this sequence with a prototype 23-base pair promoter sequence for T7 RNA polymerase shows overall homology between positions -17 and +4 with conserved divergence at residues -2 and between -10 and -12. Furthermore, careful examination of the nucleotide sequences around 45.0 and 64.8 T3 map units shows that the putative RNA sequences arising from these regions by overlapping transcription from upstream promoters can be arranged into stable stemloop structures thought to be required for RNase III cleavage. This pattern is similar to those reported for the corresponding T7 RNA polymerase promoters on T7 DNA (Dunn. J. J., and Studier, F. W. (1983) J. Mol. Biol. 166, 477-535).

Base Sequence↗
PubMed1983

Bovine retinal pigment epithelial cells cultured in vitro: growth characteristics, morphology, chromosomes, phagocytosis ability, tyrosinase activity and effect of freezing.

We compared the bovine melanotic and amelanotic retinal pigment epithelial (RPE) cells cultivated in vitro using a number of parameters. Both cell types could be readily harvested from the eye by dissection or by enzyme treatment of the RPE. Both types of cells grew equally well in the primary culture, and in serial subcultures for over 600 days, and also after being stored frozen for over two months. The two types of cells were similar in their growth patterns, morphology, chromosome characteristics and phagocytic activity but they differed in their tyrosinase activity. Although in long-term cultures cells showed chromosome loss, a high proportion of the cells retained their normal diploid chromosome number (2n = 60) with apparently normal karyotype.

Animals↗
PubMed1981

Location, function, and nucleotide sequence of a promoter for bacteriophage T3 RNA polymerase.

The major promoters for bacteriophage T3 RNA polymerase on the T3 genome have been mapped by DNA.RNA filter hybridization. One promoter is located in a 300-base-pair Hpa I restriction fragment near the genetic "left" end of T3 DNA. The sequence in the vicinity of the major initiation site of transcription in this region has been determined. A part of the (-)strand sequence is 5' T-A-T-T-T-A-C-C-C-T-C-A-C-T-A-A-A-G-+1 G-G-A-A-U 3'. Comparison of this sequence with the prototype 23-base-pair promoter sequence for bacteriophage T7 RNA polymerase shows a striking pattern of homology and divergence. Between positions -9 and +4, the sequences are virtually identical, whereas between positions -17 and -10, the sequences are quite different. It is postulated that these sequence subsets may perform different functions in transcription initiation by the phage RNA polymerases.

Base Sequence↗
PubMed1980

Construction of a restriction map of bacteriophage T3 DNA.

A restriction endonuclease cleavage map of bacteriophage T3 DNA has been constructed. The enzymes used and, within parentheses, the number of their cleavage sites on T3 DNA are: HindIII (1), XbaI (1), BglII (1), KpnI (2), MboI (9), and HpaI (17). The size and the relative location of each fragment have been established, defining an accurate physical map of T3 DNA.

Chromosome Mapping↗