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Biomedical subjects

S Garg

Publications and source records attributed to S Garg.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparison of seropositivity of HIV, HBV, HCV and syphilis in replacement and voluntary blood donors in western India.

A 5 year retrospective study from June, 1994 to May, 1999 was conducted at Zonal Blood Transfusion Centre, Umaid Hospital and Department of Pathology, Dr. SN Medical College and Associated Group of Hospitals, Jodhpur (Rajastha, Western India. Donors were evaluated for seroprevalence of HIV, HBV, HCV and Syphilis. A Total 46,957 donors were tested, out of which 42,291 (90.1%) were replacement donors and 4666 (9.0%) were voluntary donors. The incidence of HIV was 0.44% in total donors, more in replacement (0.461%) as compare to voluntary (0.279%). The seroprevalence of HBV in total donor was 3.44%. The replacement donors had high incidence (3.52%) as compared to voluntary donors (2.57%). The incidence of HCV seropositivity was 0.285% (5 month data), all were replacement donors (0.328%). The seroprevalence of VDRL in total donor was 0.22%, more in replacement donor (0.239%) as compare to voluntary donors (0.129%). Hence forth, it has been observed that voluntary blood donation is more safe and advocated as compare to replacement donation, as high incidence of HIV, HBV, HCV and Syphilis are observed in replacement donors.

Adolescent↗
PubMed2000

The scope and potential of vaginal drug delivery.

The vagina, in addition to being a genital organ with functions related to conception, serves as a potential route for drug administration. Mainly used for local action in the cervico-vaginal region, it has the potential of delivering drugs for systemic effects and uterine targeting. Currently available vaginal dosage forms have several limitations, necessitating the need to develop novel drug delivery systems. In addition, consideration of the regulatory aspects and consumer preferences for vaginal formulations is also required in the early stages of development.

Journal Article↗
PubMed2000

Occlusive systolic bridging of circumflex artery.

Intramural course of coronary arteries is a well known phenomenon on autopsy. On angiography, however, it is usually seen in relation to the left anterior descending artery. Clinically this entity may be associated with myocardial ischemia, infarction or sudden cardiac death. In this case we report an unusual angiographic finding of circumflex coronary bridging.

Adult↗
PubMed2000

Osmotically controlled oral drug delivery.

It is advantageous to deliver some drugs with short half-life, and which are to be given frequently for chronic ailments, in the form of controlled-release (CR) formulations. The orally administered drugs, in the form of conventional matrix or reservoir type formulations, pose problems of bioavailability fluctuations due to gastric pH variations. Moreover, the release of drug(s) from these systems is affected by the hydrodynamic conditions of the body. Osmotically controlled drug delivery systems utilize the principles of osmotic pressure for the controlled delivery of active agent(s). The release rate of drug(s) from these systems is independent of the physiological factors of the gastrointestinal (GI) tract to a large extent. In the present review, theory underlying the delivery of drugs from osmotic systems is presented. Different types of oral osmotic systems, their advantages over conventional matrix and reservoir types of systems, and their applications are also discussed. Finally, some of the limitations, adverse effects, and patent and market status of these systems are reviewed. These systems form a major segment of drug delivery products. Because of their advantages and strong market potential, it appears that the future of osmotic systems in rate-controlled oral drug delivery is promising.

Administration, Oral↗
PubMed2000

Effect of acetaminophen on the accuracy of glucose measurements obtained with the GlucoWatch biographer.

BACKGROUND: Improved glycemic control significantly reduces long-term microvascular complications of diabetes mellitus associated with chronic hyperglycemia. The GlucoWatch biographer is designed to facilitate intensive diabetes management by providing automatic, frequent, and noninvasive glucose readings up to three times per hour for as long as 12 hours. METHODS: The device extracts glucose through intact skin using reverse iontophoresis and measures the extracted glucose with an electrochemical biosensor. A clinical trial was performed to assess the effect of acetaminophen, a potential interference for traditional blood glucose meters, on the accuracy of the GlucoWatch biographer in adult subjects with diabetes (n = 18). One thousand milligram doses of acetaminophen were administered to subjects in two groups: one to achieve Cmax (peak acetominophen concentration) at the time of biographer calibration and the other to achieve Cmax during the measurement period. The biographer readings were compared to serial fingerstick blood glucose measurements. RESULTS: Time profiles over 9 hours show close tracking of the biographer glucose results with fingerstick blood glucose measurements for all groups. The mean difference between the two measurements is between 8 and 12 mg/dL for all groups. The mean absolute value of the relative difference is less than 20%, and more than 93% of the points were in the clinically acceptable (A+B) region of the Clarke Error Grid. No statistically significant differences were found for any accuracy measurement across all groups. CONCLUSIONS: The GlucoWatch Biographer provides frequent measurements of glucose over a 12-hour period with high accuracy. No effect of therapeutic dosage of acetaminophen on the accuracy of the glucose readings was found.

Acetaminophen↗
PubMed2000

Lipid risk factor correlates of ischemic heart disease as diagnosed by myocardial perfusion scintigraphy.

Patients with known coronary artery disease frequently change their lifestyles (e.g., diet, exercise, and smoking habit) after the diagnosis is made. Such changes can alter lipid risk factor levels and obscure etiologic risk factor associations with the presence of coronary artery disease. It is therefore preferable to determine the contribution of potential risk factors before the diagnosis of coronary artery disease has been established. In this trial, we used stress nuclear myocardial perfusion imaging to diagnose coronary artery disease in patients presenting for evaluation of chest pain. Two groups of age- and sex-matched patients were identified: a normal group (patients with no evidence of coronary artery disease), and an abnormal group (patients whose scans indicated the presence of significant coronary artery disease due to either fixed or reversible perfusion defects). Blood samples were drawn before scanning and analyzed for lipid risk factors. Compared to the normal group, the abnormal group had higher levels of triglycerides (189±91 vs. 135±51 mg/dL, p=0.003), lower levels of high-density lipoprotein cholesterol (39±9 vs. 45±14 mg/dL, p=0.037), and higher levels of small, dense low-density lipoprotein (LDL(3)) (42±18 vs. 32±13 mg/dL, p=0.007). Total cholesterol, low-density lipoprotein, and lipoprotein(a) levels were similar between groups. These findings suggest that ischemic heart disease, as assessed by myocardial perfusion scintigraphy, is more closely associated with the low high-density lipoprotein/high triglyceride syndrome than with increased low-density lipoprotein or total cholesterol levels. (c) 2000 by CHF, Inc.

Journal Article↗
PubMed2000

Effect of timing of ondansetron administration on incidence of postoperative vomiting in paediatric strabismus surgery.

This prospective, randomized, double-blinded study evaluated the effect of the timing of ondansetron administration on its antiemetic efficacy in children undergoing elective strabismus surgery. One hundred and twenty children aged one to 15 years, ASA physical status 1 or 2, were randomly allocated to receive intravenous ondansetron 100 micrograms/kg either at induction (Group 1) or at the end of the surgery (Group 2). All patients had general anaesthesia induced and maintained with nitrous oxide and halothane, muscle relaxation with vecuronium, endotracheal intubation, reversal with neostigmine and glycopyrrolate, and pethidine 0.5 mg/kg analgesia. Episodes of nausea and vomiting were evaluated at 0 to 2, 2 to 6 and 6 to 24 hour intervals by a blinded observer. Demographic data, duration of anaesthesia, type of surgery, incidence of previous postoperative nausea or vomiting and motion sickness and number of patients who developed oculocardiac reflex requiring atropine treatment were similar in both groups. The incidence of emesis in the first 24 hours following surgery was similar in both groups (35% Group 1, 33.3% Group 2, P = 1.00). Severity of emesis (median number of emetic episodes, rescue antiemetic requirement and mean time to the onset of first episode of emesis) and mean time to discharge from the post anaesthesia care unit were also similar in the two groups. We conclude that the timing of ondansetron administration either before or after the surgical manipulation of extraocular muscles had similar antiemetic efficacy following strabismus surgery in children.

Adolescent↗
PubMed1999

Early post implantation contraceptive effects of a purified fraction of neem (Azadirachta indica) seeds, given orally in rats: possible mechanisms involved.

Neem seed and leaf extracts have immunomodulators that induce cellular immune reactions. These aspects of neem were exploited in earlier studies, where the oral administration of the neem seed extracts in rodents and primates could completely abrogate pregnancy at an early post implantation stage. Complete restoration of fertility was observed in the animals treated in the subsequent cycles. For the purpose of using neem as a long term contraceptive, an activity guided fractionation, followed by identification and characterization of the biologically active fraction from neem seeds was carried out. Sequentially extracted fractions of neem seeds were tested orally at an early post implantation stage in rats. The hexane extract of the neem seeds was found to be biologically active and was the precursor for the final active fraction. The active fraction, identified as a mixture of six components, could completely abrogate pregnancy in rodents up to a concentration of 10%. No apparent toxic effects could be seen following treatment with the fraction. The treatment with the active fraction caused a specific activation of T lymphocyte cells of CD8+ subtype as well as phagocytic cells followed by elevation in cytokines gamma-interferon and TNF. The results of the present study show that a pure active fraction of neem seeds could be obtained for the purpose of early post implantation contraception when given orally, and its mechanism of action seems to be by activating cell mediated immune reactions.

Abortifacient Agents↗
PubMed1999

Noninvasive glucose monitoring: comprehensive clinical results. Cygnus Research Team.

CONTEXT: Intensive diabetes management using frequent blood glucose measurements to guide therapy has been shown to significantly improve short- and long-term outcomes. Development of a device that makes possible frequent, automatic, painless, and accurate measurements of glucose would facilitate intensive management. OBJECTIVE: To determine the accuracy of the GlucoWatch automatic glucose biographer (Cygnus Inc) compared with that of serial blood glucose measurements. DESIGN: Multicenter comparative study of the GlucoWatch biographer and the HemoCue blood glucose analyzer (Aktiebolaget Leo) performed between August 29 and October 17, 1998. Participants wore up to 2 biographers during the 15-hour study session and performed 2 fingersticks per hour for comparative blood glucose measurements. The biographers were calibrated with a single HemoCue measurement after a 3-hour warm-up period. Diet and insulin were manipulated to produce a broad glycemic range during the study. SETTING: Controlled clinical environment at 2 diabetes centers and 3 contract research organizations in the United States. PARTICIPANTS: A total of 92 subjects (mean [SD] age, 42.1 [15.1] years; 59.8% women) with type 1 or 2 diabetes requiring treatment with insulin. MAIN OUTCOME MEASURES: Mean error, mean absolute error, correlation, slope, and intercept using Deming regression, and clinical significance of differences between biographer readings and blood glucose measurements using the Clarke error grid. RESULTS: Results showed close tracking of blood glucose over a range of 2.2 to 22.2 mmol/L (40-400 mg/dL) for up to 12 hours using a single point calibration. The biographer readings lagged behind serial blood glucose values by a mean of 18 minutes. An analysis of 2167 data pairs shows a linear relationship (r = 0.88; slope = 1.03; intercept = -0.33 mmol/L [-6 mg/dL]) between biographer readings and serial glucose measurements. The mean absolute error between the 2 measurements was 15.6% (mean error [SD], -0.07 [1.82] mmol/L [-1 [33] mg/dL]), and 96.8% of the data fell in the therapeutically relevant regions of the error grid analysis. CONCLUSION: These results demonstrate close agreement between GlucoWatch biographer readings and blood glucose measurements using repeated fingerstick blood samples. The automatic, frequent, and noninvasive measurements obtained with the biographer provides more information about glucose levels than the current standard of care.

Adult↗
PubMed1999

Distribution of Vibrio cholerae O1 antigen biosynthesis genes among O139 and other non-O1 serogroups of Vibrio cholerae.

The organization and distribution of the genes responsible for O antigen biosynthesis in various serogroups of Vibrio cholerae were investigated using several DNA probes derived from various regions of the genes responsible for O1 antigen biosynthesis. Based on the reactivity pattern of the probes against the various serogroups, the cluster of genes responsible for the O1 antigen biosynthesis could be broadly divided into six groups, designated as class 1-6. The class 3 cluster of genes corresponding to gmd to wbeO, wbeT and a part of wbeU was specific for only the O1 serogroup. The other cluster of genes (class 1, 2, 4-6) reacted with other serogroups of V. cholerae. These data indicate that serotype conversion in V. cholerae does not depend on a simple mutational event but may involve horizontal gene transfer not only between V. cholerae strains but also between V. cholerae and species other than V. cholerae.

Base Sequence↗
PubMed1999

Queuing for coronary angiography during severe supply-demand mismatch in a US public hospital: analysis of a waiting list registry.

CONTEXT: Adverse cardiac events have been reported in patients waiting for either coronary surgery or angioplasty. However, data on the risk of adverse events while awaiting coronary angiography are limited, and none are available from a US population. OBJECTIVE: To quantify cardiac outcomes in patients waiting for elective coronary angiography. DESIGN, SETTING, AND PARTICIPANTS: Observational cohort study of 381 adult outpatients (mean [SD] age, 55 [12] years; 64% male; 61% white) on a waiting list for coronary angiography at a US tertiary care public teaching hospital during 1993-1994. MAIN OUTCOME MEASURES: Rates of cardiac death, nonfatal myocardial infarction, and hospitalizations for unstable angina or heart failure as a function of amount of time spent on a waiting list. RESULTS: Sixty-six patients were dropped from the waiting list but were included in the study analysis. During a mean (SD) follow-up of 8.4 (6.5) months, cardiac death, myocardial infarction, and hospitalization occurred in 6 (1.6%), 4 (1.0%), and 26 (6.8%) patients, respectively. The probability of events was minimal in the first 2 weeks and increased steadily between 3 and 13 weeks. By Cox multivariate analysis, 2 variables independently identified an increased risk of adverse events: a strongly positive treadmill exercise electrocardiogram or positive stress imaging result at referral (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.22-4.16; P=.01) and the use of 2 to 3 anti-ischemic medications (OR, 1.98; 95% CI, 1.19-3.96; P=.04). Among 311 patients who ultimately underwent angiography, those with adverse events had a higher prevalence of coronary disease (96% vs 60%; P<.001), more frequently required revascularization (93% vs 53%; P<.001), and had longer hospital stays (mean [SD], 6.2 [4.3] vs 1.3 [0.7] days; P=.001). CONCLUSION: Our data suggest that in a cohort referred for coronary angiography, delaying the procedure places some patients at risk for death, myocardial infarction, unplanned hospitalization, a longer hospital stay, and, potentially, a poorer prognosis. Waits longer than 2 weeks should be avoided, and patients with strongly positive stress test results and those who require 2 to 3 anti-ischemic medications should be prioritized for early intervention.

Aged↗
PubMed1999

Genetic determination of islet cell autoimmunity in monozygotic twin, dizygotic twin, and non-twin siblings of patients with type 1 diabetes: prospective twin study.

OBJECTIVE: To test the hypothesis that non-diabetic dizygotic and monozygotic twin siblings of patients with type 1 diabetes have a similar high prevalence of islet cell autoantibodies, thus suggesting that islet cell autoimmunity is mainly environmentally determined. DESIGN: Prospective twin study. SETTING: Two specialist centres for diabetes in the United States. PARTICIPANTS: Non-diabetic monozygotic twin (n=53), dizygotic twin (n=30), and non-twin (n=149) siblings of patients with type 1 diabetes; 101 controls. MAIN OUTCOME MEASURES: Analysis of progression to diabetes and expression of anti-islet autoantibodies. RESULTS: Monozygotic twin siblings had a higher risk of progression to diabetes (12/53) than dizygotic twin siblings (0/30; P<0.005). At the last follow up 22 (41.5%) monozygotic twin siblings expressed autoantibodies compared with 6 (20%) dizygotic twin siblings (P<0.05), 16 (10.7%) non-twin siblings (P<0.0001), and 6 (5.9%) controls (P<0.0001). Monozygotic twin siblings expressed multiple (>/=2) antibodies more often than dizygotic twin siblings (10/38 v 1/23; P<0.05). By life table analysis the probability of developing positive autoantibodies was higher among the monozygotic twin siblings bearing the diabetes associated HLA DQ8/DQ2 genotype than in those without this genotype (64.2% (95% confidence interval 32.5% to 96%) v 23.5% (7% to 40%) at 10 years of discordance; P<0.05). CONCLUSION: Monozygotic and dizygotic twins differ in progression to diabetes and expression of islet cell autoantibodies. Dizygotic twin siblings are similar to non-twin siblings. These two observations suggest that genetic factors play an important part in determination of islet cell autoimmunity, thus rejecting the hypothesis. In addition, there is a high penetrance of islet cell autoimmunity in DQ8/DQ2 monozygotic twin siblings.

Adolescent↗
PubMed1999

Study of the vaginal tolerance to Acidform, an acid-buffering, bioadhesive gel.

Vaginal tolerance tests were performed with a new potential microbicidal and spermicidal product, an acid-buffering vaginal gel (Acidform) without or with nonoxynol-9 (N-9). The potential advantages over other vaginal products include keeping a low pH, decrease of the irritating effect of N-9 on the cervix or vaginal mucosa associated with greater retention of the product after application, and decreasing "messiness" as compared to other vaginal products. Three groups of six women were admitted and randomly assigned to use Acidform with 0%, 2.5%, and 5% N-9. Colposcopic evaluation for vulvar, vaginal, and cervical signs of irritation was performed and photographs were taken, following a specific World Health Organization protocol, at time 0, and after 24 h and 6 days of application of the gel. No irritation or symptom was reported by users of Acidform without N-9. A generalized and intense erythema in cervix was observed in 10 of 12 Acidform/N-9 users and abrasion occurred in nine of them. Vulvar irritation was seen in seven of these 10 volunteers. N-9 concentration in the gel (2.5% or 5.0%) was not related to the findings. No ulcer, exulceration, or de-epithelialization was observed. Acidform without N-9 was well tolerated by volunteers, but it was unable to protect the cervix, vagina, and vulva from the N-9 effects.

Adult↗
PubMed1999

Thrombopoietin (Tpo) in the fetus and neonate: Tpo concentrations in preterm and term neonates, and organ distribution of Tpo and its receptor (c-mpl) during human fetal development.

Little is known about thrombopoietin (Tpo) production in human fetuses and neonates. As a step toward determining whether Tpo is relevant to platelet production in the fetus and neonate, we hypothesized that: (1) like other cytokines, Tpo is present in the cord blood in higher concentrations than in adult plasma; (2) Tpo and its receptor (c-mpl) are expressed in fetuses at, and following, 5-6 weeks post-conception (when platelet production begins); and (3) the sites of Tpo and c-mpl production in the fetus are similar to those of adults. We quantified Tpo, by ELISA, in the plasma of 50 adults, as well as in the umbilical cord plasma of 50 preterm and term infants. We also characterized, by RT-PCR, the organ distribution of Tpo and c-mpl during fetal development (at 8 and 16 weeks). Tpo concentrations were measurable (> or =41 pg/ml) in only two of the 50 adult samples (44 and 46 pg/ml), but in 24 of the 50 cord plasma samples (of the 24 samples, the median was 62 pg/ml; mean+/-SD, 80+/-39 pg/ml). Tpo levels did not correlate with either gestational age or platelet count at birth. Similarly to adults, in the fetal tissues, Tpo transcripts were found in all organs tested, but the most dense bands were from liver. C-mpl transcripts were also predominantly from liver. We conclude that: (1) Tpo is present in higher concentrations in cord plasma than in venous plasma of adults; (2) Tpo and c-mpl transcripts are detected in human fetuses as early as the onset of platelet appearance; and(3) Tpo and c-mpl have a similar organ distribution in fetuses and adults.

Adult↗
PubMed1999

Effect of multiple antigenic exposures in the gut on oral tolerance and induction of antibacterial systemic immunity.

We have analyzed oral tolerance of microbial antigens in an experimental model in which mice are treated orally with a single small dose of soluble antigen and challenged systemically with the antigen in complete Freund's adjuvant. We found that, while oral administration of sonicated extracts of either Leishmania major, Leishmania donovani, or Staphylococcus aureus was tolerogenic, as was administration of the nominal antigen ovalbumin or conalbumin, oral administration of Escherichia coli or Salmonella typhimurium sonicated extract was not. Since E. coli is an enteric commensal that colonizes the intestine soon after birth, these data suggested that lack of demonstrable oral tolerance may be related to the frequency of oral exposure to an antigen. In support of this, we found that multiple oral doses of ovalbumin or S. aureus or L. donovani antigens did not increase systemic hyporesponsiveness beyond that achieved with a single oral dose. We have also tested the ability of mice fed with sonicates of the tolerogenic S. aureus or the nontolerogenic S. typhimurium to clear a subsequent systemic infection with the homologous bacteria and found that, while clearance of S. aureus was unaffected by prior feeding, clearance of S. typhimurium was actually enhanced. The data suggest that frequent oral antigenic exposure may eventually lead to induction of systemic immunity in tolerant mice.

Administration, Oral↗
PubMed1999

A mycobacterial extracytoplasmic sigma factor involved in survival following heat shock and oxidative stress.

Extracytoplasmic function (ECF) sigma factors are a heterogeneous group of alternative sigma factors that regulate gene expression in response to a variety of conditions, including stress. We previously characterized a mycobacterial ECF sigma factor, SigE, that contributes to survival following several distinct stresses. A gene encoding a closely related sigma factor, sigH, was cloned from Mycobacterium tuberculosis and Mycobacterium smegmatis. A single copy of this gene is present in these and other fast- and slow-growing mycobacteria, including M. fortuitum and M. avium. While the M. tuberculosis and M. smegmatis sigH genes encode highly similar proteins, there are multiple differences in adjacent genes. The single in vivo transcriptional start site identified in M. smegmatis and one of two identified in M. bovis BCG were found to have -35 promoter sequences that match the ECF-dependent -35 promoter consensus. Expression from these promoters was strongly induced by 50 degrees C heat shock. In comparison to the wild type, an M. smegmatis sigH mutant was found to be more susceptible to cumene hydroperoxide stress but to be similar in logarithmic growth, stationary-phase survival, and survival following several other stresses. Survival of an M. smegmatis sigH sigE double mutant was found to be markedly decreased following 53 degrees C heat shock and following exposure to cumene hydroperoxide. Expression of the second gene in the sigH operon is required for complementation of the sigH stress phenotypes. SigH is an alternative sigma factor that plays a role in the mycobacterial stress response.

Amino Acid Sequence↗
PubMed1999

Expression of growth factor ligand and receptor genes in preimplantation stage water buffalo (Bubalus bubalis) embryos and oviduct epithelial cells.

The temporal pattern of expression of genes for several growth factor ligands and receptors was examined in preimplantation water buffalo embryos and oviduct epithelial cells using RT-PCR. The identity of the resulting PCR products was confirmed by their expected size, restriction analysis, Southern blot hybridization and nucleotide sequence analysis. Preimplantation stage embryos from the one-cell to the blastocyst stage were derived after maturation, fertilization and culture of oocytes in vitro. Expression of members of the insulin-like growth factor (IGF) family was observed predominantly in preimplantation stage embryos and oviduct epithelial cells. Similarly, transcripts encoding insulin and IGF-I receptors were detected at each stage of embryonic development. The mRNA transcript of the IGF-I receptor was not detected in oviduct epithelial cells, but a prominent band corresponding to the insulin receptor was observed. Insulin and IGF-II mRNA were expressed as maternal transcripts that were not detected at the two- to four-cell stage but were present as zygotic transcripts at the eight-cell stage. Transcripts encoding IGF-I were detected in oviduct epithelial cells, but were not observed in any of the preimplantation stage embryos. Transforming growth factor (TGF) alpha and beta and epidermal growth factor mRNA transcripts were not detected in any of the preimplantation stage embryos. These results indicate that IGF-I acts via a paracrine mechanism to promote growth and development of preimplantation water buffalo embryos. Similarly, IGF-II appears to act through a heterologous autocrine mechanism via the IGF-I or the insulin receptor. Furthermore, the presence of TGF-alpha in oviduct epithelial cells indicates that it may have a critical role during development.

Amino Acid Sequence↗