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Biomedical subjects

N C Sharma

Publications and source records attributed to N C Sharma.

At least 37 records · Page 2Linked to original sources
PubMed2000

A 3-month comparative investigation of the safety and efficacy of a new toothbrush: results from two independent clinical studies.

PURPOSE: To compare the efficacy of a new toothbrush featuring a novel brush head design with those of two established toothbrushes by measuring plaque and gingivitis over a period of 12 weeks. MATERIALS AND METHODS: The Oral-B CrossAction toothbrush was compared with the Dr. Best InterDent and Crest DeepSweep toothbrushes in two independent, parallel-group, examiner-blind clinical studies. Each study involved approximately 100 healthy individuals from a general population. At baseline, after 23-25 hrs of no oral hygiene, oral hard and soft tissues were examined and whole mouth, marginal and approximal plaque scores and whole mouth gingivitis scores were recorded. Subjects in the two studies were asked to use their assigned toothbrush twice a day. No instruction in brushing technique or brushing time was given. After a period of 6 weeks and finally after 12 weeks, subjects in the studies were reassessed for oral tissue status, and their plaque and gingival indices were rescored. RESULTS: In each of the two studies, the tested toothbrushes significantly reduced levels of plaque and gingivitis. The CrossAction toothbrush was, however, more effective in reducing both plaque and gingivitis over 12 weeks, the differences in favor of the CrossAction being statistically significant. All the toothbrushes tested in this investigation were found to be safe with no evidence of hard or soft tissue trauma.

Adolescent↗
PubMed1999

Identification of bovine sperm specific polypeptides reactive with antisperm antibodies.

The present study was taken to characterize molecular weights of sperm specific polypeptides antigenic to rabbits and calf with the aim to assess their immunoreactivity with IgG antibodies in sera from immuno-infertile cows. Seropositivity for antisperm IgG antibodies in 75 repeat breeder and 15 pregnant control cattle was tested by cellular ELISA using washed spermatozoa antigen from 4 bulls. Molecular weights of bovine sperm polypeptides antigenic to rabbit and calf were determined by 10% SDS-PAGE and Western blotting. Molecular weights of sperm peptides reactive with sera from immuno-infertile cows were also determined. Seropositivity of antisperm IgG antibodies for bull I, II, III and IV was 23.6, 14.6, 26.6 and 20%, respectively. A total of 16 polypeptides were discernible on gel. Out of these, 7 polypeptides were immunoreactive with sera from hyperimmunized rabbits as compared to 3 poly-peptides which reacted with sera from hyper-immunized calf. Only two polypeptides were reactive with sera from immuno-infertile cows. Variable number of sperm polypeptides and their immunoreactivity have been reported in different species. Antigenicity of different polypeptides in sperm needs further investigations.

Animals↗
PubMed1999

A short-term brushing model for assessing antiplaque/antigingivitis dentifrice effectiveness: a pilot study.

This pilot clinical study was conducted to evaluate the utility of a short-term brushing model for assessing the inhibition of supragingival plaque and gingivitis by an essential oil-containing dentifrice formulation. Forty-two qualifying subjects entered and completed this double-blind, parallel group, controlled study. At baseline, subjects received an oral soft and hard tissue examination and were also scored for plaque, gingivitis and bleeding, both visually and invasively. Subjects received a supragingival prophylaxis and were randomly assigned to an experimental essential oil-containing dentifrice or its vehicle control. Subjects brushed unsupervised for one minute, twice daily for three weeks, after which all clinical examinations were repeated. All examinations were performed by a qualified and calibrated examiner. Analyses of covariance were used to compare inter-group means for each of the three outcome variables. Compared to its vehicle control, the experimental dentifrice produced statistically significant (p < 0.0001) reductions of 39.6% for plaque, 10.8% for gingivitis, and 65.4% for bleeding. No adverse events were observed or reported. The results of this pilot study suggest that three weeks of conventional use may be an adequate duration to demonstrate effectiveness of an essential oil-containing dentifrice. Confirmation of these results in a duplicate study is desirable to assess the reliability of the model. Furthermore, the utility of this model to determine the effects of formula modifications to the antiplaque and antigingivitis activity of active agents needs to be explored.

Adolescent↗
PubMed1999

The clinical effectiveness of a dentifrice containing triclosan and a copolymer for controlling breath odor measured organoleptically twelve hours after toothbrushing.

The objective of this double-blind clinical study was to investigate the effectiveness of a dentifrice containing triclosan and a copolymer, Colgate Total Toothpaste, for controlling breath odor twelve hours after brushing the teeth compared to a placebo dentifrice which did not contain triclosan or a copolymer. Breath odor was evaluated by a panel of four expert judges using a nine-point hedonic scale. Following a baseline evaluation of breath odor, prospective study subjects who presented scores above the threshold value for unpleasant breath odor were stratified by score, and randomized into two treatment groups. Subjects were provided with a soft-bristled toothbrush, and brushed their teeth thoroughly in their regular and customary manner with their assigned dentifrice. Subjects refrained from dental hygiene, breath mints, or mouth rinses for the next twelve hours, after which they were once again evaluated for breath odor. Sixty-three (63) adult male and female subjects from the Mississauga, Ontario, Canada area participated in the study. At twelve hours after brushing their teeth, subjects in both dentifrice treatment groups presented mean breath odor scores which were statistically significantly lower than the mean scores observed at baseline. However, the difference between the mean twelve-hour breath odor scores differed significantly between the two dentifrices. The mean twelve-hour breath odor score for the Colgate Total Toothpaste group was 4.77, which is within the range of values corresponding to pleasant breath odor; the mean twelve-hour breath odor score for the placebo group was 6.05, which is above the value corresponding to unpleasant breath odor. Thus, the results of this double-blind clinical study support the conclusion that Colgate Total Toothpaste provides effective control of breath odor at twelve hours after brushing the teeth.

Adolescent↗
PubMed1998

A comparison of two electric toothbrushes with respect to plaque removal and subject preference.

PURPOSE: To compare the safety and plaque removal efficacy, and subject preference of two electric toothbrushes in a single-blind, randomized, split-mouth study. MATERIALS AND METHODS: The devices studied were the Braun Oral-B 3D Plaque Remover and the sonicare electric toothbrush. The 3D toothbrush combines the clinically proven oscillating/rotating action of the D9 with a sonic frequency pulsating action in the direction of the long axis of the bristles, giving a three-dimensional cleaning action. At an initial visit, the subjects (n = 44) were given a baseline examination of the oral soft tissues and a full mouth prophylaxis and instructed in the use of the two products, which was followed by a 4-week training period. After 2 weeks of using each toothbrush on alternate days, brushing technique was checked. After a further 2 weeks, having abstained from oral hygiene for 48 hours, two contralateral quadrants of the mouth were randomly assigned to be cleaned by the subjects with each toothbrush. Plaque assessments and soft tissue examinations were made before and after brushing. Plaque was evaluated according to a refinement of the Modified Navy Plaque Index. At the end of the study, subjects completed a product evaluation questionnaire. RESULTS: Plaque levels were significantly reduced by both toothbrushes (P = 0.001), but the efficacy of the 3D electric toothbrush was significantly greater than that of the sonicare toothbrush (P = 0.001) for all comparisons. Plaque reduction was particularly marked in the interproximal areas, reaching 87% with the 3D product, compared with 68% for sonicare (P = 0.001). In the responses to the questionnaire, the majority of subjects stated that they preferred the 3D toothbrush (88% vs 12%), mainly because of the smaller size of the brush, ease of control and overall maneuverability.

Adult↗
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↗