Determination of ibogaine in plasma by gas chromatography--chemical ionization mass spectrometry.

Ibogaine is naturally occurring indole alkaloid that is currently being considered as a treatment medication for drug dependence. Although there have been a variety of investigations regarding the mechanisms of action and pharmacology of ibogaine, relatively little has been reported regarding quantitative methods. Because of the paucity of analytical methodologies, studies involving the pharmacokinetics and metabolism of ibogaine have also been limited. A method is described for the determination of ibogaine levels in plasma by gas chromatography -- methane chemical ionization mass spectrometry. [13C2H3]Ibogaine was synthesized and used as an internal standard to control for recovery during sample preparation. The assay requires one ml of plasma and is shown to be a selective and sensitive means of ibogaine quantitation.

The effect of Parodontax dentifrice on gingival bleeding.

In this study on twenty-two adult subjects, the effectiveness of Parodontax dentifrice was compared to a control dentifrice on gingival bleeding parameters. The periodontal probe bleeding index of Ainamo and Bay, modified to evaluate slight and moderate bleeding, was used to evaluate efficacy. There was no significant difference between the two groups at baseline. After four weeks, Parodontax dentifrice produced a significant decrease (p < 0.01) in bleeding on probing compared both to baseline (p < 0.01) and to the control group (p < 0.05), and an increase (p < 0.05) in the number of sites with no bleeding compared to the control dentifrice. The control had no significant decrease in bleeding on probing from baseline to four weeks. The number of bleeding sites were significantly reduced in the Parodontax dentifrice group from baseline to week four (p < 0.001), and there was no significant statistical change in the number of bleeding sites for the control group. The Parodontax dentifrice group bleeding sites at four weeks were significantly lower than the control group (p < 0.05).

The effect of two toothpastes on plaque and gingival inflamation.

In this study on 60 adult subjects, the effective of Parodontax, a dentifrice containing herbal ingredients and sodium bicarbonate abrasive, was compared to a non-marketed new toothpaste containing herbal ingredients and calcium hydrogen phosphate as the abrasive. Plaque, gingivitis and gingival bleeding parameters were scored. The periodontal probe bleeding index of Ainamo and Bay was modified to score slight and moderate bleeding. In this first four-week period all subjects used the new toothpaste. After this period the new toothpaste produced a significant decrease (p<0.01) in gingivitis and bleeding on probing, but no effect on plaque was observed. During the second period of eight weeks the subjects were randomly divided into two groups, one using Parodontax and the other group continuing with the new toothpaste. The study design was a double-blind procedure. At the end of the 12-week study period the plaque index showed no changes in both groups. The gingivitis and bleeding indices decreased significantly (p<0.001) by 40% in both groups compared to the baseline examination.

Comparison of a double-textured prototype manual toothbrush with 3 branded products. A professional brushing study.

BACKGROUND: The consensus has been that there is no one superior design of manual toothbrush for plaque removal, despite, in some cases, encouraging findings from laboratory studies. The user appears the major variable and may mask differences in brush efficacy. AIMS: The aim of this study was to compare 2 new double-filament texture brushes with 3 established brands for plaque removal, under standardised conditions of professional brushing. METHOD: The study was a blind, randomised crossover design, balanced for residual effects. A panel of 15 subjects suspended tooth cleaning for 3 days. On day 4, plaque was scored from 6 sites per tooth before and after a 2-min professional toothbrushing. A washout period of at least 3 days was allowed between study periods. RESULTS: Overall plaque removal was 50% with no significant differences between brushes, a 3% absolute difference in average total mouth plaque separating brushes. However, at upper- and mid-buccal sites, a not significant 8% and a significant 9% difference, respectively, in plaque removal were recorded in favour of one of the prototype brushes, and at the mid-lingual site, there was a non-significant 10% difference in favour of one branded brush. Other sites were cleaned similarly by all brushes except for reduced plaque removal from buccal compared to lingual surfaces and interproximal compared to mid-surface sites. Highly significant subject differences in plaque removal were noted which may be relevant to inherent anatomical difficulties in tooth cleaning for some individuals. Period effects were not significant, supporting the consistency in brushing by the professional brusher. CONCLUSION: The method appeared capable of detecting small benefits of brush design. However, the benefits reported must be taken within the context of an overall lack of difference between brushes. The method could be used to set and record a minimum level of efficacy for toothbrushes.

The use of professional brushing to compare 3 toothbrushes for plaque removal from individuals with gingival recession.

BACKGROUND: Toothbrush filament configuration now varies considerably, usually with the intention of improving plaque removal overall or from specific sites. AIMS: The aim of the study was to compare 2 branded toothbrushes with a brush designed with a convex filament head arrangement to improve plaque removal from teeth with buccal gingival recession. METHODS: The study was a randomised, 3-treatment, double-blind crossover design balanced for residual effects and involving 18 healthy volunteers. On day 1, subjects suspended toothcleaning and returned to the clinic on day 4. Plaque was scored by area and index before and after 2 min of toothbrushing with the allocated brush. Brushing was performed by a hygienist allocating a timed 15 s to each of the 8 buccal and lingual quadrants. 3 days was allowed between treatment periods. RESULTS: Plaque accumulation differed considerably by site as did plaque removal. Overall plaque removal was 40%. Analysis showed significant subject differences but, no significant period or treatment differences. CONCLUSIONS: Consistent with other reports, it must be concluded that brush design is not a major variable in plaque removal. However using this "robot"-like model, the dentition of some individuals and specific dental surfaces are inherently more difficult to clean than others.

Comparative professional plaque removal study using 8 branded toothbrushes.

BACKGROUND AND AIM: Considerable interest has been shown in the plaque removal properties of modern toothbrush designs. The primary aim of the study was to compare the plaque removal properties of 8 relatively recent designs of manual toothbrush using a professional tooth brusher and within a commonly used time frame. A secondary aim was established to utilise the data to observationally appraise plaque accumulation together with the patterns of removal as a consequence of using the timed professional tooth brusher. METHOD: The method was an 8-period, single-examiner, randomized, blind cross-over study involving 24 healthy volunteers, balanced for residual effects. Subjects accumulated plaque over a 4 day no oral hygiene period. On day 4, the accumulated plaque was scored by plaque index at the mesial, mid and distal sites of each of the buccal and lingual surfaces of the assessed teeth. Subjects were then removed from the assessment area where they received a professional brushing timed to last 48 s. Brushing was completed according to pre-study training without toothpaste and was followed by a re-scoring of the remaining plaque. A washout period of 3 days was then allowed prior to the next period during which normal oral hygiene was resumed. RESULTS: Similar quantities of plaque accumulated in each arch, although the difference between the buccal and lingual surfaces was of the order of 30%. The professional toothbrusher removed approximately 40% of the accumulated plaque in the 48 s allocated. The buccal surfaces were most effectively cleaned (approximately 45%) compared with the lingual (approximately 25%), with the plaque removal in the mesial and mid sections approaching 40% and 60% respectively. The difference in performance between the test brushes corresponded to 5% of the residual plaque values with none being significantly more efficient overall. Pair wise site comparisons did produce differences of the order of 10% (p=0.004) at the mesio-buccal, and 8% (p=0.030) at the mid-buccal sites respectively in favour of 2 brushes compared to one other brush. CONCLUSIONS: These data derived from a standardized brushing method support the contention of many researchers that there is no one superior design of manual toothbrush. The minor and few site differences in favour of some brushes are unlikely to be of clinical significance to gingival health. This leaves uncontested the conclusion that the user is by far the most significant variable. Perhaps methods such as used in the present study could be more gainly employed to set a minimum standard of toothbrush efficacy.

Mortality from cardiovascular diseases among potash miners exposed to heat.

We assessed mortality rates in a cohort of French potash miners between 1977 and 1987. The cohort comprised all workers of a potash mine active on January 1, 1977, or subsequently hired, with at least 3 years of employment. We compared the mortality of the subcohort exposed to heat from underground work (U) with the mortality of those who had never worked underground (D). The overall mortality was low [standardized mortality ratio (SMR) = 0.89, based on 570 deaths] and was lower among underground workers (age-standardized mortality rate = 660 per 100,000 person-years, 266 deaths) than among daylight workers (age-standardized mortality rate = 710 per 100,000 person-years, 304 deaths). Mortality from ischemic heart diseases (IHD) was higher for underground workers than for daylight workers (relative risk = 1.6). As exposure to heat decreased over time, we analyzed the mortality according to period of hire: within underground workers, we observed a downward trend for mortality from IHD which contrasted with a stable mortality from IHD among daylight workers. Among subjects who left for medical reasons, IHD mortality was five times greater in the heat-exposed group compared with daylight workers. The data are consistent with an increased risk of ischemic heart diseases from a hot environment that is offset by a strong healthy worker effect.

The use of gamma radiation for the elimination of Salmonella from frozen meat.

The use of a gamma radiation process for the elimination of Salmonella from frozen meat is considered with particular reference to the treatment of boned-out horsemeat and kangaroo meat imported into the UK and intended for use as pet meat.Examination of dose/survival curves produced for several serotypes of Salmonella in frozen meat shows that a radiation dose of 0.6 Mrad. will reduce a population by at least a factor of 10(5). The influence on the radiation resistance of salmonellas of such factors as preirradiation growth in the meat and temperature during irradiation have been examined and considered. It is also demonstrated with both preinoculated and naturally contaminated meat that postirradiation storage in the frozen state does not lead to the revival of irradiated salmonellas.The properties of Salmonella survivors deliberately produced in meat using conditions of irradiation designed to simulate a commercial process are studied after six recycling treatments through the process. There were no important changes in characteristics normally used for identification of Salmonella but radiation resistance was lowered. Survivors grown in situ in meat after irradiation showed an abnormally long lag phase, and removal of competitive microflora in meat by the radiation treatment can influence the growth of salmonellas.

Abrasion and stain removal by different manual toothbrushes and brush actions: studies in vitro.

BACKGROUND AND AIMS: A limited amount of data using flat trim multitufted toothbrushes shows that abrasion of substrate surfaces by a standard toothpaste varies dependent on filament stiffness and configuration; soft brushes producing the most abrasion. The aims of these studies in vitro were to assess toothpaste abrasion of acrylic and stain removal by 5 proprietary medium toothbrushes with different head filament arrangements, and a prototype brush with rectangular filaments. The prototype brush had a medium texture in the long axis and soft texture at right angles to the long axis. MATERIAL AND METHOD: Optically clear acrylic was used as the substrate for abrasion by a standard toothpaste. Loss of substrate was determined by profilometry after 5000, 10000, 15000 and 20000 linear or rotary brushing actions. Stain removal was determined spectrophotometrically from optically clear acrylic specimens stained by chlorhexidine tea soaking sequences. Stained specimens were brushed with water using linear or rotary actions and measurements taken every 10 s to 60 s. RESULTS: Abrasion was progressive with increasing strokes and the pattern for each brush and brush action was to a first approximation linear. Overall, abrasion was significantly greater with linear compared to rotary action. Also overall brushes differed in the abrasion produced with both actions and particularly at greater exposure times. Within brush differences for the two motions were all significant by 20000 strokes except for the prototype brush. Stain removal was progressive over time with each brush but the pattern was non-linear. For the proprietary brushes the rotary motion removed less stain. For the prototype brush more stain was removed with the rotary action. Overall brushes differed significantly in stain removal within each motion and for each motion most differences between the proprietary and prototype brushes reached significance. CONCLUSIONS: The differences between brushes for both abrasion and stain removal must in large part relate to the filament contact area with the substrate surface. Whilst the model may not be predictive of clinical differences, it could find use to establish minimum criteria for toothbrush action.

Dentine hypersensitivity in subjects recruited for clinical trials: clinical evaluation, prevalence and intra-oral distribution.

Relatively few studies have reported on the frequency, distribution and severity of dentine hypersensitivity (DH) in subjects recruited for clinical trials of desensitizing agents. Potential subjects (n= 48 M, 81 F, mean age 35.1 years) for inclusion into such a study were screened to determine the extent of the problem. 117 subjects (41 M, 76 F) mean age 24.9 years were clinically examined. Evaluation by questionnaire indicated that the prevalence of DH was proportionately higher in the 20-29.9 years (34.9%), and 30-39.9 years groups (33.3%), respectively. Sensitivity to cold was the main presenting symptom. Tactile (probe) and cold air (dental air syringe) stimuli were used to clinically evaluate DH. Of the teeth eligible for evaluation 1561/3136 (49.8%) responded to either one or both of the test stimuli; 274/3136 (8.7%) responded to tactile only stimulation, 779/3136 (24.8%) to thermal only stimulation and 508/3136 (16.2%) to both tactile and thermal stimulation. Of those teeth responding to the stimuli, 477 (30.6%) were premolars, 437 (28%) incisors, 415 (26.8%) molars and 232 (14.9%) canines. The results agree with those of previously reported studies in that DH is most frequently observed on premolars and that proportionately more teeth are sensitive to evaporative than to tactile stimulation. Furthermore it would appear from the results of the study that tactile is less effective than thermal/evaporative stimulation in the evaluation of DH.

[In-vitro activity of enoxacin: a multicenter study]. / In vitro-Aktivität von Enoxacin: Eine multizentrische Studie.

The in vitro activity of enoxacin was tested in 14 German microbiological centers shortly after the introduction of the drug in Germany. 2748 unselected clinical isolates including 15 bacterial species were analysed using microtiter plates. The MIC90-values were as follows: Staphylococcus aureus 4 mg/l, Enterococcus faecalis 16 mg/l, Enterobacteriaceae 0.5 mg/l, Pseudomonas aeruginosa 8 mg/l. There is good correlation between these results and those of former investigations. It is known that quinolones are only moderately active against enterococci. 8.5% of S. aureus, and 1.4% of Enterobacteriaceae were found to be resistant (MIC greater than 4 mg/l). As to P. aeruginosa, the study revealed that despite a generally low rate of resistance in specific clinical settings, specific problems can arise: in one institution, the MIC90 of P. aeruginosa was 32 mg/l, with a resistance rate of 56.1% (n = 57). In the other centers the MIC90 was 2 mg/l and the resistance rate 5.0% (n = 302). In the first center, many of the isolates were from paraplegic patients or patients with cystic fibrosis pretreated with quinolones. This study will be repeated in two years' time in order to determine an eventual change in resistance.