Nicotine increases the collagen-degrading ability of human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: The objective of this study was to determine the effects that nicotine and the combination of nicotine and Porphyromonas gingivalis supernatant have on human gingival fibroblast-mediated collagen degradation. MATERIAL AND METHODS: Human gingival fibroblasts were cultured with 25-500 microg/ml of nicotine in collagen-coated six-well plates. On days 1-5, the conditioned media was collected for zymography and western blot analyses of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). The cells were then removed and the collagen cleavage visualized by Coomassie blue staining. To examine the combined effect, 250 microg/ml of nicotine and 10% v/v culture supernatant of P. gingivalis ATCC 33277 were added to the human gingival fibroblasts. The mRNA levels of multiple MMPs and TIMPs were monitored. RESULTS: Nicotine increased the human gingival fibroblast-mediated collagen cleavage. The MMP-14 and MMP-2 produced by the nicotine-treated human gingival fibroblasts more readily underwent zymogen activation. Nicotine treatment resulted in TIMP-2 redistribution to the cell surface. The mRNAs of multiple MMPs and TIMPs were unaltered by nicotine. An additive collagen cleavage effect was observed when the human gingival fibroblasts were treated with both nicotine and P. gingivalis. CONCLUSION: Nicotine increased human gingival fibroblast-mediated collagen degradation, in part through the activation of membrane-associated MMPs. Nicotine and P. gingivalis had an additive effect on human gingival fibroblast-mediated collagen degradation.

Scaling for the VO2-to-body size relationship among children and adults.

The purpose of this study was to examine the relationship between oxygen consumption (VO2) and both body surface area (BSA) and body size among 30 prepubertal children, 30 circumpubertal children, and 30 adults to determine which scaling model is most appropriate for making comparisons between these populations. All subjects participated in maximal treadmill testing and submaximal treadmill testing at two absolute work rates. Resting metabolic rate was measured on a subset of 48 subjects. It was determined that the submaximal VO2 (VO2 sm)-to-body size relationship provided the most appropriate model for comparisons. Analyses revealed a stronger linear relationship between VO2 sm and BSA than VO2 sm and body mass. Logarithmic transformation of the data revealed an allometric exponential relationship between VO2 sm and body mass. The exponent relating body mass to VO2 sm at 3 mph (1.34 m/s) was 0.60, whereas the exponent at 5 mph (2.24 m/s) was 0.75. VO2 values at 5 mph were significantly less variable (P < or = 0.05) than those at 3 mph. Therefore the exponent of body mass to the 0.75 power was considered a more appropriate basis for analysis. It was determined that, overall, a scaling factor of BSA or body mass to the 0.75 power both provide a more appropriate method of comparison than a simple ratio standard of body weight.

Induction of nuclear aberrations by smokeless tobacco in epithelial cells of human oral mucosa.

Cytologic and cytogenetic studies were performed to assess the prevalence of somatic cell genetic damage in 48 young adults equally divided to represent users and nonusers of smokeless tobacco. Exposure was ascertained by measuring saliva cotinine using capillary gas chromatography. Squamous epithelial cells sampled from the oral mucosa demonstrated significant cytologic alterations associated with tobacco exposure. The frequency of micronucleated cells was significantly (P less than .01) higher in the labial mucosa of exposed (2.22%) compared to unexposed (0.27%) individuals. The frequency of micronuclei varied widely between exposed subjects but was higher in heavily (2.48%) compared to lightly (1.29%) exposed individuals as measured by saliva cotinine levels. Morphologic classification of epithelial cell nuclei showed that the frequency of cells with normal nuclear structure was significantly (P less than .01) reduce in exposed individuals. Analysis of oral epithelial cells of five additional nonusers of smokeless tobacco but wearers of orthodontic appliances to stimulate abrasion demonstrated no difference from the nonexposed control group. Unlike the case with cigarette smokers, peripheral lymphocyte sister-chromatid exchange frequency was not affected by exposure to smokeless tobacco. The oral cytology data, however, support an interpretation of exposure-dependent nuclear alterations, including micronuclei, in the oral epithelium associated with the use of smokeless tobacco. Altogether, results suggest that use of smokeless tobacco may cause genetic damage to cells in the oral epithelium.

Determination of metal stoichiometry in LaSrCu-oxide, YBaCu-oxide, BiCaSrCu-oxide superconducting films and bulk samples.

Metal stoichiometry in superconducting bulk materials and thin films made of LaSrCu-oxides, YBaCu-oxides, and BiCaSrCu-oxides were determined by inductively coupled plasma atomic-emission spectrometry (ICP-AES) after dissolution in a 1:1 mixture of 20% v/v hydrochloric and nitric acids. The method provides reliable results, with which a variety of manufacturing processes can be optimized. The precision of the metal determinations ranges from 3 to 9%.

Smokeless tobacco addiction: a threat to the oral and systemic health of the child and adolescent.

The use of smokeless tobacco (ST) within the United States has increased greatly in recent years, especially among adolescent boys and young men. Recent national data completed from several large scale studies indicate that 10-12 million Americans use some form of ST. Representing a significant systemic and oral health risk, ST usage can produce a wide range of negative effects on both soft and hard oral tissues. These oral conditions include bad breath, discolored teeth and restorative materials, excessive tooth surface wear (abrasion), decreased ability to taste and smell, gingival (gum) recession, advanced periodontal soft and hard tissue destruction, tooth loss, soft tissue erythema and leukoplakia. Long-term ST usage is directly correlated to an increased risk of cancer of the mouth, larynx, throat and esophagus. Much of the destruction of oral tissues is related to the localization of the tobacco quid; i.e., it is habitually held in only one spot in the mouth. Nicotine from ST can activate the sympathetic nervous system thereby significantly increasing heart rate, blood pressure, cardiac stroke volume and output and coronary blood flow. A common misconception is that ST is a 'safe' alternative to smoking cigarettes. Several recent Surgeon General's Reports list ST as being addictive. It is highly possible that ST users will 'graduate' to cigarettes if they eventually conclude that these products are socially unacceptable, inconvenient or out of vogue. Health professionals, educators, parents and schoolchildren need to be informed about the significant health risks associated with ST use.

Overreporting of smokeless tobacco use by adolescent males.

This study evaluates the impact of a pipeline assessment (salivary cotinine determination) on the accuracy of self-reported use of cigarettes and smokeless tobacco by 160 rural seventh- and eighth-grade males ranging in age from 12 to 16. Half of them were randomly assigned to complete a questionnaire on tobacco use prior to revealing the biochemical validation materials and collecting samples. The others had the samples collected prior to receiving and completing the questionnaires. The questionnaire-first group reported significantly greater smokeless tobacco use than did the pipeline-first group. Only for the latter were their self-reports significantly corroborated by the cotinine results. These results suggest that the utilization of a biochemical pipeline not only can improve self-reported tobacco use but also may help identify perceptions about the social desirability of using harmful substances.

Evaluation of biochemical validation measures in determination of smoking status.

This study was designed to evaluate the use of salivary cotinine, salivary thiocyanate, and expired-air carbon monoxide as biochemical validation measures for assessing the smoking status of adults. The participants were 20 known non-smokers plus 216 admitted smokers and 102 proclaimed quitters participating in a clinical trial of approaches to facilitate smoking cessation. Conventional analytical procedures were utilized. By use of data from known non-smokers and admitted smokers, the sensitivity and specificity of the validation measures were as follows: salivary cotinine, 99% and 100%; expired-air carbon monoxide, 96% and 100%; and salivary thiocyanate, 67% and 95%, respectively. The salivary cotinine and expired-air carbon monoxide tests confirmed smoking cessation for 55% and 74%, respectively, of the proclaimed quitters. The length of time since quitting was significantly related to the results observed with the latter measures. Consideration of these observations along with various practical factors suggests that expired-air carbon monoxide assays may be the validation measure of choice for most clinical trials.

How hospitals are fostering effective trusteeship.

More emphasis is being placed on the need for hospitals to establish board development and assessment policies. A 1985 survey of governing boards by the American Hospital Association reveals how many hospitals have continuing education and evaluation programs for their trustees, as well as the tools and criteria they use as the basis for those activities.

Comparisons of various salivary parameters in smokers before and after the use of a nicotine-containing chewing gum.

This study was designed to compare various salivary parameters between smokers and non-smokers and to determine the influence of a nicotine-containing chewing gum (used to aid in quit-smoking efforts) upon these same parameters. At the baseline examination, subjects were assigned to one of three groups: non-smokers who did not utilize any gum, smokers provided a nicotine-containing gum, and smokers provided a placebo gum. Saliva was collected from all subjects and analyzed for acidogenicity and buffer pH as well as for levels of thiocyanate, lactoperoxidase, lysozyme, lactoferrin, and secretory IgA. After 15 weeks of gum usage, saliva was again collected from each subject and the identical analyses performed. Significant differences were observed between smokers and non-smokers with regard to three parameters: The saliva of smokers contained greater concentrations of thiocyanate and lower concentrations of lactoferrin, at the baseline examination and after the 15-week test period. In addition, the CO content of alveolar air was higher in smokers at both examination periods. In contrast, the use of the nicotine gum per se had no effect on any of the test parameters.

Effects of nicotine-containing chewing gum on oral soft and hard tissues: A clinical study.

A double-blind clinical trial was conducted to determine whether the use of a chewing gum containing 2.0 mg nicotine (as an adjunct to a stop-smoking program) had any effects upon oral health. A total of 193 adults who smoked cigarettes volunteered with informed consent, were given routine dental prophylaxes, and were examined for the presence of plaque, stained pellicle, gingivitis, calculus, and general oral pathosis. The subjects were then randomly assigned to use either a nicotine-containing or a placebo chewing gum. After 15 weeks the subjects were recalled and re-examined. Smoking cessation was determined through questionnaire and analysis of the carbon monoxide content of alveolar air. At the completion of the study, 79 subjects had used the placebo gum and 78 had used the nicotine gum. Data analysis indicated that the nicotine chewing gum had no significant influence on any of the oral health parameters graded, as compared to the placebo gum. The continuation of smoking, however, was associated with significant increases in gingivitis and calculus rates.

Influence of lithium upon dental caries in the rat.

Two studies were performed on rats to determine the post-eruptive cariostatic effects of lithium alone and in combination with fluoride. The results failed to demonstrate any cariostatic effects of lithium when evaluated in this manner, nor any enhancement by lithium of the cariostatic activity of fluoride.