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Biomedical subjects

V Gupta

Publications and source records attributed to V Gupta.

At least 19 recordsLinked to original sources
PubMed2000

Insect cells as HLA-restricted antigen-presenting cells for the IFN-gamma elispot assay.

Measurement of specific cellular immune responses in patients undergoing immunotherapy is difficult. Established approaches, including cytotoxicity (e.g., 51Cr release) and cytokine release assays, require in vitro culturing for several weeks or more of patients' peripheral blood mononuclear cells (PBMC) and the addition of exogenous cytokines. Therefore, the immunological response does not reflect in vivo conditions. To address these disadvantages, we have used an interferon-gamma (IFN-gamma) Elispot assay for detecting peptide-specific CD8(+) lymphocytes in PBMC. A limitation of this assay is the lack of a reproducible source of antigen-presenting cells (APCs). Currently available APCs often lead to significant background levels. It has been shown that transfected insect cells can express empty MHC class I molecules on their surface. We have transfected Drosophila melanogaster S2 cells and the Lepidopteran line Sf9 with the gene encoding human HLA-A2.1. We demonstrate that insect cells expressing a human HLA molecule effectively function as APCs in the IFN-gamma Elispot assay. Initially the feasibility of the assay was assessed using CD8(+) T cells from HLA-A2.1(+) donors with known reactivity against an HLA-A2.1-binding epitope of the influenza matrix protein. Use of insect cells as APCs abrogated background spots, increasing sensitivity. We further observed that a short-term prestimulation of PBMC with peptide-pulsed insect cells markedly enhanced the frequency of peptide-specific T cells that could be measured in the Elispot assay without increasing the background. This approach was then used to measure CD8(+) T cell reactivity to a peptide from tyrosinase, an antigen that is processed and presented by melanoma cells. Insect cells expressing human HLA molecules provide a standard APC for monitoring CD8(+) T cell responses to tumor and viral peptides during immunotherapy.

Animals↗
PubMed2000

Influence of ethanol on lead distribution and biochemical changes in rats exposed to lead.

In the present study, an attempt has been made to investigate the effect of ethanol consumption on the distribution of lead in different regions of brain and body organs of male albino rats. Lead when administered intragastrically, for a period of eight weeks resulted in almost uniform accumulation of this metal in all the regions of brain, which increased by almost two fold when ethanol was given along with lead. Lead was also seen to compartmentalise in almost all the tissues of the body to varying extents, with the highest accumulation in the kidney. A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in ZPP levels in animals during the course of treatment, which increased further when ethanol was administered along with lead. The activity of delta-ALAD and AChE in blood was significantly decreased in lead as well as ethanol treated animals. However, in animals coexposed to lead and ethanol, the inhibition of delta-ALAD was not significantly different, when compared to only lead-treated animals. The results suggested that animals exposed to ethanol and lead simultaneously accumulate higher levels of lead in blood and brain of animals making them more vulnerable to the haematological and neurological toxic effects of lead.

Acetylcholinesterase↗
PubMed2000

Intra-ocular pressure and haemodynamic changes after tracheal intubation and extubation: a comparative study in glaucomatous and nonglaucomatous children.

This prospective, controlled study was conducted to compare the effects of tracheal intubation and extubation on intra-ocular pressure changes and haemodynamic parameters in paediatric patients with and without glaucoma. The children were scheduled for intra-ocular surgery. Twenty children with normal intra-ocular pressure and 15 with glaucoma were studied. A standardised general anaesthetic was administered to both groups. After 5 min of anaesthesia, intra-ocular pressure, heart rate and noninvasive blood pressure were measured. These measurements were repeated 30 s and 2 min after tracheal intubation. Further measurements were taken before, and 30 s and 2 min after extubation. The increase in intra-ocular pressure after intubation was greater in the glaucomatous group than in the normal group. The increase in intra-ocular pressure was greater after extubation than intubation in both groups, but was similar in the two groups. However, because of the already increased intra-ocular pressure in glaucomatous children, they may be at an increased risk of visual damage after intubation and extubation.

Anesthesia, General↗
PubMed1999

Structure-function analysis of tritrypticin, an antibacterial peptide of innate immune origin.

The structural requirements for the antibacterial activity of a pseudosymmetric 13-residue peptide, tritrypticin, were analyzed by combining pattern recognition in protein structures, the structure-activity knowledge-base, and circular dichroism. The structure-activity analysis, based on various deletion analogs, led to the identification of two minimal functional peptides, which by themselves exhibit adequate antibacterial activity against Escherichia coli and Salmonella typhimurium. The common features between these two peptides are that they both share an aromatic-proline-aromatic (ArProAr) sequence motif, and their sequences are retro with respect to one another. The pattern searches in protein structure data base using the ArProAr motif led to the identification of two distinct conformational clusters, namely polyproline type II and beta-turn, which correspond to the observed solution structures of the two minimal functional analogs. The role of different residues in structure and function of tritrypticin was delineated by analyzing antibacterial activity and circular dichroism spectra of various designed analogs. Three main results arise from this study. First, the ArProAr sequence motif in proteins has definitive conformational features associated with it. Second, the two minimal bioactive domains of tritrypticin have entirely different structures while having equivalent activities. Third, tritrypticin has a beta-turn conformation in solution, but the functionally relevant conformation of this gene-encoded peptide antibiotic may be an extended polyproline type II.

Amino Acid Sequence↗
PubMed1999

The crystal structure of recombinant rat pancreatic RNase A.

The three-dimensional structure of rat pancreatic RNase A expressed in Escherichia coli was determined. The backbone conformations of certain critical loops are significantly different in this enzyme compared to its bovine counterpart. However, the core structure of rat RNase A is similar to that of the other members of the pancreatic ribonuclease family. The structural variations within a loop bordering the active site can be correlated with the subtle differences in the enzymatic activities of bovine and rat ribonucleases for different substrates. The most significant difference in the backbone conformation was observed in the loop 15-25. This loop incorporates the subtilisin cleavage site which is responsible for RNase A to RNase S conversion in the bovine enzyme. The rat enzyme does not get cleaved under identical conditions. Molecular docking of this region of the rat enzyme in the active site of subtilisin shows steric incompatibility, although the bovine pancreatic ribonuclease A appropriately fits into this active site. It is therefore inferred that the local conformation of the substrate governs the specificity of subtilisin.

Amino Acid Sequence↗
PubMed1999

Asymmetric distribution of phosphatidylethanolamine in C. albicans: possible mediation by CDR1, a multidrug transporter belonging to ATP binding cassette (ABC) superfamily.

By using two molecular probes, we demonstrate that only 4% of total phosphatidylethanolamine (PtdEtn) in the plasma membrane (PM) of a human pathogenic yeast, Candida albicans, is present in its external half. Evidence is presented to show that the availability of PtdEtn could be related to the expression of a multidrug transporter CDR1 of C. albicans, and the process is energy-dependent. A homozygous CDR1 disruptant strain of C. albicans shows almost 23% reduction in the external labelling of PtdEtn. This report shows that, similar to human MDRs, yeast multidrug transporter could also be involved in aminophospholipid translocation.

ATP-Binding Cassette Transporters↗
PubMed1999

Grapefruit juice increases the bioavailability of artemether.

OBJECTIVE: To evaluate the effect of grapefruit juice on the pharmacokinetics of artemether in plasma and saliva after a single oral dose and to detect concentration-dependent electrocardiographic changes (bradycardia and QTc prolongation). METHODS: Six healthy male subjects were given a standard breakfast followed by two tablets of 50-mg artemether administered with water; 1 week later, the tablets were administered with 350 ml double-strength fresh frozen grapefruit juice. For 8 h, 17 blood- and saliva samples were collected, and 17 electrocardiograms were recorded. Drug and metabolite concentrations were measured by means of high-performance liquid chromatography with electrochemical detection. The pharmacokinetic parameters were determined using a one-compartment model. RESULTS: Grapefruit juice significantly (P = 0.001) increased the mean peak concentration (Cmax) of artemether more then twofold from 42 (SD 17) ng/ml to 107 (28) ng/ml. The time to reach Cmax (tmax) with grapefruit juice was 2.1 (0.6) h compared with 3.6 (17) h with water (P = 0.02). The area under the concentration time curve (AUC) almost doubled with grapefruit juice from 177 ng x h/ml to 336 ng x h/ml (P = 0.003). The elimination half-life remained unchanged (1.0 h vs 1.3 h). No major changes in the kinetics of the metabolite dihydroartemisinin were detected. Low artemether levels and zero dihydroartemisinin levels were found in saliva. No influences of artemether were observed on 17 electrocardiograms during the 8 h after drug intake in particular there were no signs of bradycardia or QTc prolongation. CONCLUSION: Grapefruit juice significantly increases the oral bioavailability of artemether without an effect on the elimination half-life. It suggests a role for intestinal CYP3A4 in the presystemic metabolism of artemether.

Adult↗
PubMed1999

Radial artery in CABG: could the early results be comparable to internal mammary artery graft?

BACKGROUND: The accidental detection of patency of radial artery grafts, by Acar, which had been labeled as blocked 18 years earlier, has led to its revival as a conduit in coronary artery bypass surgery. We used radial artery as one of the grafts in 287 patients from February 1996 to June 1998. Here we present our early clinical experience and the midterm angiographic follow up of the initial 62 patients. METHODS: A no touch, atraumatic harvesting technique coupled with gentle hydrostatic and pharmacological dilatation of the radial artery graft was employed. Radial artery was used to revascularize coronary vessels with >80% proximal stenosis. Postoperatively, the patients were administered a low dose nifedipine that was continued for 6 months thereafter. The patients were followed up clinically after discharge from the hospital and angiographic evaluation of the grafted radial artery by selective injection was done at a mean interval of 16.2 +/- 5.1 months (3-24 months) postoperatively. RESULTS: There was no perioperative or late myocardial infarction or mortality. No significant complications related to the harvesting of radial artery were encountered. Angiographically, the radial artery grafts were found to be patent in 96.8% of patients (60/62). Mild distal anastomotic narrowing was seen in angiogram of one patient with good filling of the target vessel. Another patient showed diffuse spasm of radial artery graft. The patency of the pedicled left internal mammary grafts was also 98.2% (56/57). All the patients were asymptomatic. CONCLUSIONS: Radial artery seems to be an excellent alternate arterial conduit for myocardial revascularization with early and midterm patency rates equivalent to that of pedicled internal mammary artery, and it should be used more often for myocardial revascularization as an adjunct to pedicled internal mammary artery graft.

Adult↗
PubMed1999

Women's status and the health of women and men: a view from the States.

We examined the status of women in the 50 American states in relation to women's and men's levels of health. The status of women in each state was assessed by four composite indices measuring women's political participation, economic autonomy, employment and earnings, and reproductive rights. The study design was cross-sectional and ecologic. Our main outcome measures were total female and male mortality rates, female cause-specific death rates and mean days of activity limitations reported by women during the previous month. Measures of women's status were strikingly correlated with each of these health outcomes at the state level. Higher political participation by women was correlated with lower female mortality rates (r = -0.51), as well as lower activity limitations (-0.47). A smaller wage gap between women and men was associated with lower female mortality rates (-0.30) and lower activity limitations (-0.31) (all correlations, P < 0.05). Indices of women's status were also strongly correlated with male mortality rates, suggesting that women's status may reflect more general underlying structural processes associated with material deprivation and income inequality. However, the indices of women's status persisted in predicting female mortality and morbidity rates after adjusting for income inequality, poverty rates and median household income. Associations were observed for specific causes of death, including stroke, cervical cancer and homicide. We conclude that women experience higher mortality and morbidity in states where they have lower levels of political participation and economic autonomy. Living in such states has detrimental consequences for the health of men as well. Gender inequality and truncated opportunities for women may be one of the pathways by which the maldistribution of income adversely affects the health of women.

Cause of Death↗
PubMed1999

Efficacy of supratarsal dexamethasone versus triamcinolone injection in recalcitrant vernal keratoconjunctivitis.

PURPOSE: To compare the efficacy of supratarsal injection of short acting dexamethasone sodium phosphate versus intermediate acting triamcinolone acetonide as a new therapeutic modality for treating eyes with recalcitrant vernal keratoconjunctivitis (VKC). METHODS: The study was a prospective, randomized, double blind, case controlled trial, including 38 eyes of 19 patients with recalcitrant VKC. Except for two initial patients who received supratarsal injection of triamcinolone acetonide in both the eyes, one eye of each patient was randomly assigned to receive either 2 mg of dexamethasone sodium phosphate or 20 mg of triamcinolone acetonide. RESULTS: Both the drugs were equally effective with no statistically significant difference in the mean time of resolution of cobblestone papillae, limbal edema, shield ulcer, SPK and relief of symptoms. The recurrence rate of disease was, however, lower following triamcinolone acetonide injection. CONCLUSIONS: Supratarsal injection of corticosteroid is a cheap, effective and safe modality of treatment for managing eyes with recalcitrant VKC. Both short acting dexamethasone and intermediate acting triamcinolone acetonide are equally effective.

Adolescent↗
PubMed1999

Immunoglobulin motif DNA recognition and heterodimerization of the PEBP2/CBF Runt domain.

The polyomavirus enhancer binding protein 2 (PEBP2) or core binding factor (CBF) is a heterodimeric enhancer binding protein that is associated with genetic regulation of hematopoiesis and osteogenesis. Aberrant forms of PEBP2/CBF are implicated in the cause of the acute human leukemias and in a disorder of bone development known as cleidocranial dysplasia. The common denominator in the natural and mutant forms of this protein is a highly conserved domain of PEBP2/CBF alpha, termed the Runt domain (RD), which is responsible for both DNA binding and heterodimerization with the beta subunit of PEBP2/CBF. The three-dimensional structure of the RD bound to DNA has been determined to be an S-type immunoglobulin fold, establishing a structural relationship between the RD and the core DNA binding domains of NF-kappaB, NFAT1, p53 and the STAT proteins. NMR spectroscopy of a 43.6 kD RD-beta-DNA ternary complex identified the surface of the RD in contact with the beta subunit, suggesting a mechanism for the enhancement of RD DNA binding by beta. Analysis of leukemogenic mutants within the RD provides molecular insights into the role of this factor in leukemogenesis and cleidocranial dysplasia.

Cleidocranial Dysplasia↗
PubMed1999

Molecular insights into PEBP2/CBF beta-SMMHC associated acute leukemia revealed from the structure of PEBP2/CBF beta.

PEBP2/CBF is a heterodimeric transcription factor essential for genetic regulation of hematopoiesis and osteogenesis. DNA binding by PEBP2/CBF alpha is accomplished by a highly conserved DNA binding domain, the Runt domain (RD), whose structure adopts an S-type immunoglobulin fold when bound to DNA. The supplementary subunit beta enhances DNA binding by the RD in vitro, but its role in the control of gene expression has remained largely unknown in vivo. Chromosome 16 inversion creates a chimeric gene product fusing PEBP2/CBF beta to a portion of the smooth muscle myosin heavy chain (PEBP2/CBF beta-SMMHC) that is causally associated with the onset of acute myeloid leukemia in humans. The three-dimensional structure of PEBP2/CBF beta has been determined in solution and is shown to adopt a fold related to the beta-barrel oligomer binding motif. Direct analysis of a 43.6 kD ternary RD-beta-DNA complex identifies the likely surface of beta in contact with the RD. The structure of PEBP2/CBF beta enables a molecular understanding of the capacity of PEBP2/CBF beta-SMMHC to sequester PEBP2/CBF alpha in the cytoplasm and therefore provides a molecular basis for understanding leukemogenic transformation.

Binding Sites↗
PubMed1999

The effect of grapefruit juice on the time-dependent decline of artemether plasma levels in healthy subjects.

BACKGROUND: Artemether is a new and effective treatment for malaria, although relapse is a problem in monotherapy. These relapses could be related to a time-dependent decline in artemether plasma levels described in multiple-dose studies and probably caused by autoinduction. The aim of this study was to evaluate the effect of grapefruit juice on the decreasing bioavailability over time of artemether. METHODS: In a randomized, two-phase crossover study, eight healthy male subjects took 100 mg oral artemether with 350 mL water or with 350 mL double-strength fresh frozen grapefruit juice once daily for 5 days. On day 1 and day 5, 17 blood samples were collected over a period of 8 hours. RESULTS: The mean peak artemether plasma concentration (Cmax) and the mean area under the concentration-time curve (AUC) after the last dose at day 5 were about one third compared with day 1, without a change in the elimination half-life after intake with water (P = .006 for Cmax; P = .005 for AUC) and with grapefruit juice (P < .001 for Cmax and AUC). Grapefruit juice increased Cmax (P = .021) and AUC (P < .001) twofold on day 1 (P = .021) and day 5 (P = .05 for Cmax; P = .004 for AUC). Dihydroartemisinin, the active metabolite, showed a twofold increase in Cmax (P = .006) and AUC (P = .001) with grapefruit juice, without time-dependent changes of pharmacokinetic parameters. CONCLUSIONS: Grapefruit juice significantly increased the oral bioavailability of artemether but did not prevent the time-dependent reduction in bioavailability. It suggests that CYP3A4 in the gut wall is one of the metabolizing enzymes of artemether but seems to not be involved in the autoinduction process.

Administration, Oral↗
PubMed1999

Diagnostic efficacy of polymerase chain reaction in granulomatous uveitis.

SETTING: The granulomatous uveitis, multifocal choroiditis and periphlebitis have been suspected to be of tubercular origin but no definitive reports about detection of etiological agents have been documented in the literature. Conventional bacteriological methods are not generally helpful in diagnosing ocular tuberculosis due to difficulty with potential morbidity associated with obtaining the biopsy material from the eye. Thus, the diagnosis of ocular tuberculosis is most often presumptive. OBJECTIVE: We evaluated the role of polymerase chain reaction (PCR) for detection of Mycobacterium tuberculosis in the aqueous humor samples obtained from eyes with active uveitis. METHODS: Aqueous samples from 53 patients having cellular reaction in the anterior chamber along with any one or more of the following: 1) active vasculitis; 2) anterior vitreous cells; 3) snowball opacities; 4) snow banking in the pars plana; 5) retinochoroiditis were withdrawn by anterior chamber paracentesis and subjected to PCR. Seventeen samples from patients with definite clinical diagnoses other than tuberculosis formed a disease control group. Fifteen aqueous samples obtained from healthy subjects undergoing routine cataract surgery served as healthy controls. PCR was performed using primers capable of amplifying a 150 b.p. segment from a conserved repetitive sequence in the genome of M. tuberculosis. RESULTS: Twenty out of the 53 samples (37.7%) in the study group were positive where as only one sample out of 17 in the disease control group (5.7%) showed a weakly positive band. No sample from the healthy control group showed a positive PCR. CONCLUSION: Our study shows that PCR can be effectively used for the diagnosis of intraocular tuberculosis in the presence of uveitis.

Aqueous Humor↗
PubMed1999

Tuberculosis of the foot.

In 44 patients with tuberculosis of the foot we identified five radiological patterns of lesions; cystic, rheumatoid, subperiosteal, kissing and spina ventosa. Cystic destruction had the best outcome and rheumatoid the poorest. All the patients were cured after antituberculous treatment for 18 months, and none required surgery.

Adolescent↗
PubMed1999

Development and implementation of guidelines for management of sedation and agitation in critically ill patients.

The article describes the development, implementation, and success of guidelines for pharmacological management of sedation and agitation in critically ill patients in a community hospital. Guidelines were developed with careful review of published literature and in cooperation with thought leaders in the institution. The primary focus of the guidelines was choice of medication and monitoring parameters and an educational campaign to ensure use of the guidelines. A prospective pharmacist intervention program was initiated for further enforcement of the guidelines. Implementation of these guidelines has resulted in a significant reduction in the cost of sedation and agitation (annual cost savings, > $40,000 per year).

Behavioral Symptoms↗
PubMed1999

School-based health centers in Louisiana: an introduction.

Up to 20% of students in America's public schools suffer from a chronic health condition. Working parents and the behavioral morbidities of the late 20th century put children at risk for poor physical health, poor mental health, and poor educational outcomes. Access to care is poor for adolescents in general and for the uninsured. School-Based Health Centers deliver primary mental and physical health care inside schools where the children are. They are run by interdisciplinary teams of professionals. They focus their efforts on primary care and prevention and collaborate with schools, parents, and the community to deliver this care.

Adolescent↗