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Biomedical subjects

S Ghosh

Publications and source records attributed to S Ghosh.

At least 595 records · Page 33Linked to original sources
PubMed1995

Approach to genotyping errors caused by nontemplated nucleotide addition by Taq DNA polymerase.

Thermostable DNA polymerases can catalyze nontemplated addition of a nucleotide to the 3' end of amplification products. This presents a potential source of error in genotyping studies employing Taq DNA polymerase to amplify microsatellite loci. Although the activity is marker specific, experimental variation is often seen in the degree of modification. Consequently, for a given microsatellite marker, an allele may be inconsistently identified as either the unmodified or modified amplification product. Full automation of high-throughput genotyping has been hampered by the need for manual editing of data because of this source of allele misidentification. In this study we estimate a 1% to 3% error rate attributable to nontemplated nucleotide addition in the ABI PRISM genotyping system. We present a PCR-based strategy to minimize this source of error.

Alleles↗
PubMed1995

A comparison of the ipsilateral cortical projections to the dorsal and ventral subdivisions of the macaque premotor cortex.

The cortical connections of the dorsal (PMd) and ventral (PMv) subdivisions of the premotor area (PM, lateral area 6) were studied in four monkeys (Macaca fascicularis) through the use of retrograde tracers. In two animals, tracer was injected ventral to the arcuate sulcus (PMv), in a region from which forelimb movements could be elicited by intracortical microstimulation (ICMS). Tracer injections dorsal to the arcuate sulcus (PMd) were made in two locations. In one animal, tracer was injected caudal to the genu of the arcuate sulcus (in caudal PMd [cPMd], where ICMS was effective in eliciting forelimb movements); in another animal, it was injected rostral to the genu of the arcuate sulcus (in rostral PMd [rPMd], where ICMS was ineffective in eliciting movements). Retrogradely labeled neurons were counted in the ipsilateral hemisphere and located in cytoarchitectonically identified areas of the frontal and parietal lobes. Although both PMv and PMd were found to receive inputs from other motor areas, the prefrontal cortex, and the parietal cortex, there were differences in the topography and the relative strength of projections from these areas. There were few common inputs to PMv and PMd; only the supplementary eye fields projected to all three areas studied. Interconnections within PMd or PMv appeared to link hindlimb and forelimb representations, and forelimb and face representations; however, connections between PMd and PMv were sparse. Areas cPMd and PMv were found to receive inputs from other motor areas--the primary motor area, the supplementary motor area, and the cingulate motor area--but the topography and strength of projections from these areas varied. Area rPMd was found to receive sparse inputs, if any, from these motor areas. The frontal eye field (area 8a) was found to project to PMv and rPMd, and area 46 was labeled substantially only from rPMd. Parietal projections to PMv were found to originate from a variety of somatosensory and visual areas, including the second somatosensory cortex and related areas in the parietal operculum of the lateral sulcus, as well as areas 5, 7a, and 7b, and the anterior intraparietal area. By contrast, projections to cPMd arose only from area 5. Visual areas 7m and the medial intraparietal area were labeled from rPMd. Relatively more parietal neurons were labeled after tracer injections in PMv than in PMd. Thus, PMv and PMd appear to be parts of separate, parallel networks for movement control.

Animals↗
PubMed1995

Cell-specific expression of the human Na+,K(+)-ATPase beta 2 subunit isoform in the nonpigmented ciliary epithelium.

PURPOSE: To evaluate the patterns of expression of beta subunit isoforms of the Na+,K(+)-ATPase and H+,K(+)-ATPase in the human eye and to determine the cell-specific distribution of the beta 2 subunit in the human ciliary epithelium. METHODS: Total RNA extracted from human ocular tissues was screened by Northern blot analysis with cDNA probes for the human Na+,K(+)-ATPase subunit isoforms (beta 1 and beta 2) or the H+,K(+)-ATPase (alpha and beta) subunits. Antibodies were raised to the amino and carboxyl terminal regions of the human beta 2 isoform. Polymerase chain reaction was used to verify the expression of beta 2 subunit in nonpigmented ciliary epithelial cells (NPE). RESULTS: Transcripts for the Na+,K(+)-ATPase beta 1 and beta 2 subunit isoforms were present at different levels in all the ocular tissues except the lens, which expressed only beta 1. No transcripts for the alpha or beta subunits of the H+,K(+)-ATPase were detected in the eye. Isoform beta 2 specific anti-peptide antibodies V15E (N-terminus) and A18R (C-terminus) recognized a 55- to 60-kDa protein in the ciliary epithelium and the core protein of 32 kDa after N-glycanase treatment. Immunocytochemical localization within the ciliary epithelium indicates that the Na+,K(+)-ATPase beta 2 isoform is expressed preferentially in the NPE cells. The expression of Na+,K(+)-ATPase beta 2 isoform in the human NPE cell line, ODM-2, was confirmed by polymerase chain reaction amplification and Southern blot analysis. CONCLUSIONS: The Na+,K(+)-ATPase beta 2 subunit isoform, but not H+,K(+)-ATPase, was expressed widely in ocular tissues of the human eye. The restricted cellular distribution of beta 2 isoform within the NPE cells represents an important differential gene marker associated with the multiple alpha subunit isoforms of Na+,K(+)-ATPase.

Aged↗
PubMed1995

Survivability and leucocyte migration inhibition in mice immunized with cryotreated ascites fibrosarcoma cells using different freeze-thaw cycles.

Attempts have been made to assess as to what extent in vitro assay of cellular immunity, e.g. leucocyte migration inhibition (LMI) in mice immunized with different freeze-thaw cycles could reflect host resistance in vivo. While survivability of animals improved significantly by immunization with single cycle (P < 0.05) to three cycle (P < 0.001) and programmed three cycle (P < 0.001) cryo-treated tumor cells compared to controls, the percentage LMI in the same groups of animals decreased progressively. The KCl(3M) extracted tumor cell protein (antigen) of both viable and cryo-treated cells showed a progressively increased protein concentrations per 1 x 10(6) tumor cells with viable cells being least and programmed three cycle cryo-treated cells highest. The apparent discrepancy observed between percentage migration inhibition and survivability may be due to the fact that (1) survivability is a function of body's total immune response while LMI represents the response of one effector limb only; (2) immuno-regulatory mechanisms depend on a balance between activation and suppression and suppressor cells being more sensitive and of shorter life span, affect migration inhibition but not the survivability; (3) cryo-treatment alters tumor cell surface antigen affecting immunological balance; and (4) suppressor and antitumor activities against antigenic stimulation develop simultaneously in different organs and LMI performed with sensitized splenic cells, where, perhaps, suppressor cell activity dominates.

Animals↗
PubMed1995

[Ambulatory surgery in Great Britain--an overview].

Day surgery has been practised in Great Britain for many years. However, only in the last few years there has been a great surge of interest in the practice of day surgery. This has taken place despite many obstacles such as clinician's preference for more traditional approaches and initial lack of facilities and resources. Main reason for expansion of day surgery has been due to gradual change in clinical practice with new technology, search for cost efficiency, joint effort by policy makers and professionals and above all positive attitude of patients themselves towards treatment on a day care basis. In the last five years day surgery has nearly doubled in this country. Currently just under half of all elective operations are carried out on a day care basis in Great Britain. However, there is a wide variation in relation to performance of day surgery throughout the country between hospitals. This is true both for total number of surgical patients treated on a day care basis and for individual surgical procedures. Day surgery is now generally accepted as best option of treatment for over 50% of all elective surgical procedures and it is expected that by the end of this decade this figure is likely to be over 60%.

Ambulatory Surgical Procedures↗
PubMed1995

Investigation of neutrophil migration into the gut by cytology of whole gut lavage fluid.

OBJECTIVE: Radiolabelling studies have shown that neutrophils migrate into the gut lumen in inflammatory intestinal diseases. We aimed to establish whether whole gut lavage fluid can be used to investigate intestinal neutrophilia. DESIGN: A prospective single centre study comparing inflammatory bowel disease patients, patients with other gastrointestinal diseases and normal controls. METHODS: Gut lavage with a polyethylene glycol-based solution was performed in 56 patients (29 with inflammatory bowel disease). Gut lavage fluid samples were collected when the rectal effluent was clear. Cells were then separated by density gradient centrifugation, counted, and cytospin preparations examined. RESULTS: High cell counts (> 3.7 x 10(5)/ml), predominantly neutrophils, were present in 12 out of 29 inflammatory bowel disease patients and in two out of 27 others. High cell counts and luminal neutrophilia characterized active ulcerative colitis and active colonic Crohn's disease, but not active small bowel Crohn's disease, or inactive disease. CONCLUSION: Whole gut lavage fluid samples can be used to investigate luminal inflammatory cells. We observed previously unrecognized differences between small bowel and colonic Crohn's disease using this method. The mechanisms of neutrophil migration into the gut lumen may differ with disease distribution.

Cell Count↗
PubMed1995

Higher environmental temperature: effect of multiple exposures on long-term diazepam-induced changes in brain regional GABA.

The measurement of steady state level and accumulation rate of GABA and the activities of GAD and GABA-T in brain regions of adult male albino rats treated with diazepam (diazepam, 5 mg/kg/day, i.p.) and/or exposed (2 h/day) to higher environmental temperatures (higher environmental temperature, 40 degrees C) under long-term conditions (7-30 consecutive days) shows that long-term treatment with diazepam (5 mg/kg/day, i.p., for 15-30 consecutive days) reduced the GABAergic activity in the hypothalamus, corpus striatum (CS) and cerebellum (CM) without any alteration in the cerebrocortical region (CC). Multiple exposures to higher environmental temperatures for 7 consecutive days, on the other hand, enhanced GABAergic activity in hypothalamus, corpus striatum and cerebrocortical region of the rat. This higher environmental temperature-induced increase in GABAergic activity was further enhanced in the hypothalamus, but it was attenuated in the corpus striatum and became normalized in the cerebrocortical region upon the prolongation of exposure (15-30 consecutive days) to higher environmental temperature. The long-term diazepam-induced inhibition in GABAergic activity in hypothalamus and corpus striatum (but not in the cerebellum) disappeared and was finally activated following exposures (2 h/day) to higher environmental temperatures (40 degrees C) along with diazepam-treatment (5 mg/kg day, i.p.) for 7, 15 and 30 consecutive days. In the cerebellum, multiple exposures to higher environmental temperature did not significantly alter the long-term diazepam-induced inhibition of GABAergic activity or GABAergic activity in the normal rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Mechanisms of platelet dysfunction and response to DDAVP in patients with congenital platelet function defects. A double-blind placebo-controlled trial.

To examine the impact of the underlying defective platelet mechanism on the response to 1-desamino-8-D-arginine vasopressin (DDAVP, Desmopressin), we studied the effect of intravenous infusion of 0.3 microgram/kg of DDAVP in a randomized double blind placebo-controlled trial with cross-over in 18 carefully characterized patients with congenital platelet defects (CPD) and BT > or = 9 min. Eleven patients had normal dense granule stores and normal thromboxane A2 (TxA2) production (Group I), 3 patients had normal granule stores but impaired TxA2 production (Group II), and 4 had delta-storage pool deficiency (Group III). DDAVP shortened BT at 50 min (DDAVP 14.6 +/- 2.2 vs placebo 19.6 +/- 2.3 min; n = 18; mean +/- SE; p = 0.003) and 4 h (17.0 +/- 2.2 vs 19.6 +/- 2.1 min, p = 0.055), and raised plasma FVIIIC and von Willebrand factor (vWF). At 50 min DDAVP shortened BT by > or = 5 min in 8 of 11 Group I patients (mean 9.7 +/- 1.3 vs 16.3 +/- 2.8 min; p < 0.008), 1 of 3 Group II patients (11.9 +/- 3.9 vs 17.7 +/- 6.6; p = NS) and none of Group III patients (mean 30 min both arms). Ten patients (Group I or II) were managed successfully during surgical procedures with DDAVP alone. We conclude that DDAVP shortens BT in majority of CPD patients with normal dense granule stores and suggest that BT response may be dependent on the underlying platelet defect. DDAVP is a useful modality in management of selected patients, particularly those with normal dense granule stores.

Bleeding Time↗
PubMed1995

A distributed, scalable, community care network architecture for wide-area electronic patient records: modeling and simulation.

Principal systems issues relative to computerizing patient medical records that are yet to be addressed in the scientific literature include (1) the characteristics of networks, i.e. bandwidth and capacity, and their impact on the performance of the system, (2) the architecture and the underlying algorithm of the system, (3) the location and migration of medical records, (4) scalability of the system, and (5) the nature of the performance variation under heavy and light use of the network. Key parameters that affect performance include the number of patients, doctors, frequency of patient visits, and the number of electronic queries and record entries initiated during a patient-doctor interaction episode. This paper presents AMPReD, a Distributed, Scalable, Community Care Network Architecture that aims to provide Real-Time Access to Geographically-Dispersed Patient Medical Records. The AMPReD model includes stationary hospitals and medical clinics, mobile clinics, migrating doctors as well as patients, the communications network, and the patient medical record database. AMPReD's goals include (1) the accurate modeling of the propagation of medical records and (2) providing real-time access to patient medical records from anywhere in the system. To achieve these goals, an asynchronous, distributed algorithm must be developed that achieves concurrent access of multiple, autonomous databases. AMPReD is modeled and simulated for a representative community care network on a network of workstations configured as a loosely-coupled parallel processor, for different parametric combinations of number of doctors, patients, and number of queries or record entries generated corresponding to every patient-doctor interaction episode. AMPReD defines and obtains key performance measures including the idle times of the doctors, patient waiting times, the access times of queries as functions of their sizes, and the growth of the databases. In addition, AMPReD also measures the deviation of the actual time required for a patient-doctor interaction episode from the scheduled interaction interval, as a function of the network load. For the representative system selected, performance measures indicate that the network, utilizing 1/2T1 links, and the database system poses no bottleneck to the system even where the number of doctors and patients within a 30 minute interval are chosen at 192 and 200 respectively. A T1 is a standard, digital, transmission link that is rated at 1.44Mbits/sec.

Algorithms↗
PubMed1995

Bacteria in surface infections of neonates.

A bacteriological work on surface infections was done among live births (study group I) and neonates admitted in hospital (study group II). Out of 134 cases of conjunctivitis in group I Gram-negative bacilli predominated (48.5%) with Escherichia coli accounting for 29 (14.9%) cases, Klebsiella species 15 (11.2%) cases, Citrobacter freundii 3 (2.2%) cases, Pseudomons aeruginosa 18 (13.4%) cases and Aeromonas hydrophila 3 (2.2%) amongst pure isolates (73.9%). Gonococcus was noted in 2 (1.5%) cases. In group II, 41.7% were Staphylococcus aureus in pure growth (75%), compared to only 9.0% in group I. Skin infections were caused by both Staphylococcus aureus and Staphylococcus epidermidis. Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were the principal insolates from umbilical sepsis. Pseudomonas aeruginosa was isolated as pure growth from local site of noma neonatorum. Anaerobic cultures were negative in all except in 2 cases of umbilical sepsis with tetanus neonatorum revealing Clostridium tetani which however proved to be non-toxigenic. Blood cultures were positive in 4 out of 14 cases bearing 50% correlation with bacteria from surface infections. A source study established partial correlation with the cases of pseudomonas conjunctivitis. Phage typing of Staphylococcus aureus and biochemical typing failed to detect any definite marker of clinical entities, except that the skin infections were caused by group III phages predominantly (65.0%).

Bacteriophage Typing↗
PubMed1995

Deduced amino acid sequence of 2S storage protein from Brassica species and their conserved structural features.

2S seed storage albumin coding regions from five Brassica species, namely Brassica campestris, B. oleracea, B. nigra, B. juncea, and B. carinata have been cloned by PCR amplification of genomic DNA using oligonucleotide primers and their nucleotide sequences have been determined. These sequences showed more than 85% homology amongst themselves and considerable homology with some other crucifer 2S protein coding sequences. The deduced amino acid sequences showed more homology due to some inconsequential mutations in codons without changing the amino acids. Computer analysis of the protein sequences for possible secondary structure revealed a high degree of conservation of hydrophilic and hydrophobic domains and the invariant positions of cysteine residues. Unrooted phylogenic tree based on the coding region of 2S albumin from different Brassica species cloned by us and published sequences from other Cruciferae indicated that these genes originated before the evolutionary divergence of different Brassica species and were conserved due to some stringent structural and functional features required for seed metabolism.

Amino Acid Sequence↗
PubMed1995

Intestinal parasitism: a childhood problem in rural Bengal.

A study was undertaken to assess the parasitic infection rate in a rural community of West Bengal amongst children below four years of age suffering from gastrointestinal complaints. A total of 221 faecal samples were examined during November 1992 to April 1994. G. lamblia (17.2%) and E. histolytica (8.1%) were the predominant protozoas, whereas E. vermicularis (12.2%) and A. lumbricoides (8.1%) were found to be common amongst helminthic infection. A significantly lower infection rate was observed in children below one year (24.4 per cent) as compared to older age groups (66.4 per cent).

Age Distribution↗
PubMed1994

Identification of discrete segments of human Raf-1 kinase critical for high affinity binding to Ha-Ras.

A critical event in a signal transduction pathway downstream of receptor tyrosine kinases is the physical association of GTP-liganded Ras with the serine/threonine kinase, Raf-1. The binding of Raf-1 to Ras results in translocation of the kinase to the plasma membrane and facilitates its activation by an unknown mechanism. A deletion mutagenesis approach was employed to elucidate critical sequences in Raf-1 necessary for binding to Ras and to resolve seemingly contradictory data in the literature. While an N-terminal fragment consisting of residues 2-130 of Raf-1 was able to bind Ras, residues 131-147 were found to be critically important for conferring high affinity binding to Ras. Surprisingly, a second domain between residues 52-64 was an essential element for Raf-Ras interaction, although it did not appear to form an independent binding site for Ras. These findings may prove useful for the design of peptides or peptidomimetic drugs for the modulation of Raf-Ras interaction in neoplastic disorders.

Base Sequence↗