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Biomedical subjects

N C Sharma

Publications and source records attributed to N C Sharma.

At least 19 recordsLinked to original sources
PubMed1997

Isolation of Salmonella senftenberg bacteriophages.

A total of 61 bacteriophages were isolated from 100 strains of Salmonella senftenberg. Six bacteriophages were selected for typing purposes which were specific for S. senftenberg. Five phages, SasL1 to SasL5 were morphologically similar; phage SasL6 was morphologically different from the others. These phages fall into two morphological groups none of which correspond to the known tailed enterobacterial phage species. Hence, two new phage species represented by SasL1 and SasL6 are proposed.

Lysogeny↗
PubMed1996

Adjuvant effect of DEAE-dextran and tetanus toxoid on whole cell heat inactivated phenol preserved typhoid vaccine.

Active mouse protection test (AMPT) and enzyme linked immunosorbent assay (ELISA) were used to determine the immunogenicity of whole cell typhoid vaccine when administered in conjunction with either tetanus toxoid (TT) or DEAE-Dextran (DD). Immunization of mice with whole cell typhoid vaccine showed enhanced potency either when administered in conjunction with TT or DD and values were statistically significant (p < 0.05) in comparison to conventional or standard typhoid vaccines. For ELISA, the mice were immunized with 2 different schedules, one in which a single dose of 0.25 ml subcutaneously (s/c) was administered and in another two doses of 0.25 ml each s/c, 14 days apart. In case of single dose schedule of immunization D vaccine (Whole cell typhoid + 5 mg/ml DD) showed significant increase of immune response (3.201 log10) as compared to plain vaccine (2.550 log10). Two dose schedule further increased the titres to 3.856 log10. DD adjuvanted vaccine showed higher potency by AMPT as compared to the TT adjuvanted vaccine or plain vaccine. The present study clearly demonstrates that a single dose of 0.25 ml which is equivalent to half of the conventionally used single human dose of typhoid vaccine adjuvanted with DD can significantly improve the immunogenicity of the vaccine.

Adjuvants, Immunologic↗
PubMed1994

Bacteriophage typing in Salmonella bareilly.

A total of 675 strains of Salmonella bareilly received from different parts of India and France during 1959-92 were phage typed using six bacteriophages. Overall typability achieved was 90.8% with 23 distinct phage types excluding a group of untypable strains. Phage types have been defined in octal code. Simpson's coefficient was applied for diversity index having a value of 0.839. This system was found to be reproducible, stable and epidemiologically useful.

Animals↗
PubMed1994

Development of a conjoint phage typing & biotyping schema for Salmonella enterica serovar Senftenberg (S. senftenberg) & the correlation of biotypes with phage types.

A total of 287 strains of S. senftenberg received from various parts of India during 1969 to 1992 were phage typed using six lysogenic phages. The typability was 90.3 per cent and 14 different phage types could be defined excluding a small group of untypable strains. A biotyping scheme was developed utilising six characters and 13 biotypes could be defined. Stern's glycerol medium proved to be the best discriminatory medium. Diversity indeces of phage typing and biotyping schemes were 0.868 and 0.503 respectively. Better discrimination was obtained when phage types were subdivided into different biotypes with a diversity index of 0.931. The schemes were found stable, reproducible and epidemiologically useful.

Bacterial Typing Techniques↗
PubMed1994

The clinical effects on plaque and gingivitis over three-month's use of four complex-design manual toothbrushes.

The Colgate Total (formerly Colgate Precision) was evaluated along with the New Improved Crest Complete, Reach Advanced Design and Oral-B Advantage toothbrushes to compare six-week and three-month effects on plaque and gingivitis. One-hundred and ninety-three male and female participants completed a three-month, unsupervised toothbrushing study, brushing their teeth twice daily with one of these four products and a standard fluoride dentifrice. Plaque was quantified using the Rustogi et al. refinement of the Modified Navy Plaque Index. Gingivitis levels were measured using the Lobene et al Modified Gingival index. After initial screening examinations, the qualifying population (0.6 plaque, 1.8 gingivitis) was given a complete oral prophylaxis and instructed to return after forty-eight hours of no oral hygiene for baseline evaluations. The study population was split into four balanced groups after baseline examinations and assigned, by group, to use a particular toothbrush for the study duration. Subjects returned after six weeks and three months for safety and efficacy evaluations. There were no reported or observed untoward effects at any examination time in the study. Plaque and gingivitis mean values were not significantly different at baseline between the four groups. Results from this three-month clinical study demonstrated a significant reduction (p<.0001) in plaque levels and gingivitis for all of the four toothbrushes compared to baseline. At both six weeks and three months, gingivitis and plaque means were significantly lower (p<.01) in the Colgate Total group compared to the other three toothbrushes tested. When changes from six weeks to three months were statistically analyzed only the Colgate Total toothbrush significantly reduced (p<.001) gingivitis mean scores.

Adolescent↗
PubMed1993

Development and verification of the proximal/marginal plaque index.

The purpose of this study was to compare the ability of experienced and newly trained investigators to use the published Global Plaque Index and a newly developed Proximal/Marginal Index (PMI) that focuses on disclosed plaque at clearly defined proximal and marginal surfaces. Four independent clinical studies were performed, two with each index, on 11 subjects per study. In each study, examinations were conducted before and after brushing, to determine inter- and intra-examiner comparisons over a range of plaque levels. Inter-examiner reliability estimates for the PMI were at a level below Global Plaque index means. Intra-examiner agreement values were similar for both indices. Both scoring systems are considered sufficiently validated to detect product differences in clinical studies.

Clinical Competence↗
PubMed1993

A clinical study of comparative plaque removal performance of two manual toothbrushes.

A single-blind, two-phase cross-over clinical trial compared the plaque removal performance of two commercially available manual toothbrushes, Colgate Precision Full Head soft and Crest Complete soft. One hundred and one eligible adult male and female subjects refrained from toothbrushing for 24 hours and were then scored for dental plaque using the Rustogi, et al. refinement of the Modified Navy Plaque Index (Rustogi, et al. Index) on the facial and lingual surfaces of all natural teeth. Upon qualifying, subjects were stratified according to Mean Plaque Index (MPI) values and randomly assigned to one of two balanced groups. Seven days later, having refrained from oral hygiene procedures for a period of 24 hours, subjects returned for plaque scoring and the initial test toothbrushing. Their plaque was disclosed with a red disclosing solution and pre-brushing plaque scores were recorded. Subjects were assigned a test toothbrush (according to group) and brushed for an unsupervised, timed 60 seconds. They returned to the clinic and were again disclosed and evaluated for plaque. These post-brushing plaque scores were also recorded. This completed Visit 1. Subjects were instructed to resume their normal, unsupervised routine and return to the clinical site one week later for Visit 2, again with 24-hour oral hygiene abstention. At that time the alternate test toothbrush was assigned to each group in a cross-over design. Plaque scoring, toothbrushing and repeat plaque scorings were performed and recorded as at Visit 1. Before and after disclosing, plaque scoring and toothbrushing were again performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Transferable colicinogeny in Salmonella bareilly.

Twenty eight (5.6%) of the 500 isolates of S. bareilly studied were found to be colicin producers. Of these 27 (96.4%) were Col V producers. None of these produced aerobactin and 18 (64.3%) were multidrug resistant. Among 23 (85.2%) strains both drug resistance as well as colicinogeny could be transferred by conjugation. This is the first time that the transferable colicinogeny has been demonstrated in S. bareilly.

Colicins↗
PubMed1992

Comparative plaque removal efficacy of three toothbrushes in two independent clinical studies.

Two independent studies were conducted to evaluate and compare the clinical performance of three toothbrushes on plaque removal. Both studies were carried out under the same protocol. A total of 73 adult male and female subjects who met the inclusion/exclusion criteria completed Study I and 78 different subjects completed Study II. Subjects were initially screened for dental plaque eligibility. After plaque was scored on the facial and lingual surfaces of all natural teeth using the Rustogi, et al. index, qualifying subjects were randomly assigned to one of three groups on the basis of initial plaque scores and number of teeth. Subjects were then dismissed and scheduled to return for Visit 1 a week later, having abstained from all oral hygiene procedures for a prior 24-hour period. At Visit 1, each group was evaluated for plaque before brushing with their assigned toothbrush for sixty seconds. They were again scored for plaque after brushing. Subjects were dismissed and instructed to resume their normal routine and return to the clinical site for two more weekly visits. At each visit, a different test toothbrush was assigned to each group in a cross-over design. Plaque evaluations and brushing procedures were performed as in Visit 1 of the study. In both studies, the Colgate Precision toothbrush was significantly more effective (p < 0.01) than both the Oral-B 40 and Reach Full-Head soft toothbrushes in reducing the whole mouth plaque scores, as well as plaque at the gumline and at interproximal areas. The Oral-B 40 and Reach toothbrushes were not significantly different from each other with regard to plaque removal.

Adolescent↗
PubMed1990

Phase I clinical trials with three formulations of anti-human chorionic gonadotropin vaccine.

Comparative phase I clinical trials were carried out in 5 centres with three formulations of beta-hCG-based vaccines inducing antibodies against human chorionic gonadotropin. The objectives of these trials were to determine their relative immunogenicity, duration, reversibility and safety. A total of 116 tubal ligated women volunteers were enrolled in the study and 101 subjects were followed-up for one year or more until the antibody titres declined to near zero levels. Every woman receiving the vaccine produced anti-hCG and anti-tetanus antibodies. Clinical examination carried out at intervals of 4-6 weeks revealed no abnormality. No serious side effects or adverse reactions were reported with any of the formulations during primary immunization with three monthly injections of the vaccine. Eleven women, however, demonstrated hypersensitivity to test dose at the time of the booster injection. The reaction was to tetanus toxoid; gonadotropin subunits conjugated to another carrier did not evoke any such reaction. Progesterone in bleeds taken at midluteal phase, as well as complete progesterone and estradiol done in two immunized women, indicated normal ovulatory cycles. Immunization with these formulations had no significant effect on haematological, clinical chemistry and other metabolic parameters. In summary, the results indicate that none of the three beta-hCG-based contraceptive vaccines had any adverse effects clinically, on endocrine status and metabolic parameters. Formulations A and B induced comparatively higher anti-hCG titres than M. Thus, further work can be undertaken to study the efficacy of these vaccines in humans for preventing pregnancy.

Adult↗
PubMed1989

Antibody response and characteristics of antibodies in women immunized with three contraceptive vaccines inducing antibodies against human chorionic gonadotropin.

Data are presented on antibody titers generated in 88 women immunized with three formulations of antihuman chorionic gonadotropin (hCG) vaccine, namely, beta-hCG (formulation B); beta-hCG associated with alpha-subunit of ovine luteinizing hormone (LH) (formulation A) and beta-hCG + beta-ovine LH (formulation M), each linked to tetanus toxoid and cholera toxin chain B as carriers. Each formulation was tested at two dose levels (100 and 500 micrograms). All women without exception developed anti-hCG antibodies having hCG-binding capacity above 20 ng mL-1 (0.5 nM), a level considered to be the threshold for prevention of pregnancy. Formulations A and B gave relatively better immunogenic response in human subjects than M. In each case, the antibody response was reversible. The mean duration of response above 20 ng was 35 to 37 weeks for formulation A, 34 weeks for B, and 17 to 20 weeks for M. Antibodies induced by three formulations of the vaccine had high-affinity (Ka 10(9)-10(10)M-1) for binding with hCG. They were devoid of cross-reaction with human follicle-stimulating hormone and thyroid-stimulating hormone but, as expected, cross-reacted with human LH. Antibodies were competent to block the hCG induced ovarian hyperemia.

Adult↗
PubMed1987

A new scheme for phage typing Salmonella bareilly and characterization of typing phages.

A new phage typing scheme using wild bacteriophages isolated from sewage for phage typing Salmonella bareilly is described. Six hundred and thirty-seven strains of Salm. bareilly could be separated into 11 different phage types using five wild phages. Overall typability was 94.5%. These phages belonged to two different morphotypes. A1 and B1, and showed varying host range.

Animals↗
PubMed1986

Enhancement of antigonadotropin response to the beta-subunit of ovine luteinizing hormone by carrier conjugation and combination with the beta-subunit of human chorionic gonadotropin.

Previous studies have demonstrated the control of fertility in monkeys on immunization with the beta subunit of ovine luteinizing hormone (beta-oLH) along with Freund's complete adjuvant (CFA). An eventual birth control vaccine would demand immunization without CFA. Beta-oLH linked to tetanus toxoid (TT) adsorbed on alum-induced antibody response in bonnet monkeys with detoxified sodium phthalyl derivative of Salmonella enteritidis lipopolysaccharide added only in the first injection. The antibodies reacted with both LH and human chorionic gonadotropin (hCG). A higher immune response was obtained with the use of a conjugate of beta-oLH and beta-hCG linked to a common carrier (TT) or with a mixture of beta-hCG/TT and beta-oLH/TT. In both cases, the antibodies were of high affinity with Ka ranging from 5 X 10(9) to 6 X 10(10) M-1. The antibodies were devoid of reactivity with human thyroid-stimulating hormone and human follicle-stimulating hormone. Monkeys with titers above 120 ng/ml hCG binding capacity (greater than 60 ng/ml in most cases) were protected from becoming pregnant during repeated mating with males of proven fertility in ovulatory cycles.

Animals↗