Browsing by Author "Olson, Byron L."

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    Effects of nicotine on osteogenesis
    (2001) Sanoudos, Mattheos; Roberts, W. Eugene; Christen, Arden G.; Garetto, Lawrence P.; Hartsfield, James K.; Olson, Byron L.
    The purpose of this study was to demonstrate the inhibiting effects of systemically administered nicotine on osteogenesis and angiogenesis. The orthopedic expansion of a suture is a non-invasive method directly related to orthodontic treatment. This study examined the actions of nicotine related to the vascularly related osteogenic response elicited by orthopedic expansion. Sixty seven male,6-8 week old, Sprague-Dawley received 2 different dosages of nicotine (6 and 12 mg/kg/day), for a period of 14 days. Nicotine was delivered subcutaneously with the use of Alzet® Osmotic minipumps. Control animals received minipumps filled with saline. Fluorochrome labels were administered during the two-week period to mark bone formation. Ten days after minipump implantation a second surgery was performed and ring-type elastic separators were placed between the maxillary central incisors of forty-six animals. Twenty-three and ninety-five hours after expansion the animals were injected BrdU and terminated 1 hour later. The maxillae were demineralized and embedded in paraffin. The femurs and tibias were cleaned from soft tissue and embedded in methyl methacrylate. The results of this study indicate that nicotine has a dose-dependent inhibiting effect on both the osteogenic and angiogenic process in the expanded suture. After 96 hours of expansion these effects are only partially reversed. Nicotine inhibits vascular invasion and depresses osteoblast recruitment. The study indicated that there may also be a direct suppression of osteoblasts, but the principal anti-osteogenic effect of nicotine is an inhibition of the vascular proliferation and osteoblast histogenesis, associated with mechanically induced osteogenesis
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    Longitudinal Determination of Mutans Streptococci Strain Differences by Pulsed Field Gel Electorphoresis in Orthodontic Patients
    (1997) Jordan, Christopher N.; LeBlanc, Donald J.; Christen, Arden G.; Hartsfield, James K., Jr.; Miller, Chris H.; Olson, Byron L.
    Results of numerous studies have positively correlated the Dentocult® SM test(Ivoclar Vivadent, Amherst, New York) with conventional plating techniques for the enumeration of mutans streptococci in saliva. However, similar studies have not been conducted on saliva samples collected from patients undergoing orthodontic therapy. The hypotheses to be tested in this study were therefore threefold: first, that the Dentocult system is an accurate and reliable method for the determination of salivary counts of mutans streptococci when used with orthodontic patients; second, that a trend (either a general increase or decrease) in levels of mutans streptococci would be seen in orthodontic patients; and third, that because a new surface is presented due to orthodontic appliances, different strains of mutans streptococci, possibly exogenously acquired, might account for increased levels of mutans streptococci, should an increase be seen. Therefore, isolates of these bacteria obtained before and after therapy were examined by Pulsed Field Gel Electrophoresis (PFGE) for detection of strain differences. Two baseline saliva samples, and a saliva, tooth plaque, and appliance plaque sample at 1,2,3, and 4 months after commencement of full orthodontic banding and bonding were obtained from 26 patients in the Indiana University School of Dentistry graduate orthodontic clinic for bacterial enumeration and PFGE analyses. Dentocult was found to correlate extremely well with conventional plating techniques, utilizing Mitis salivarius agar supplemented with bacitracin (MSB), when salivary levels of mutans streptococci were either extremely high(> 10 6 CFU/ml saliva) (91 % correlation) or quite low ( <10 5 CFU/ml saliva) ( 100% correlation). For salivary levels of mutans streptococci between these limits, the percent agreement was not as substantial (49% correlation). Salivary levels >10 6 CFU/ml saliva of mutans streptococci was used as an indicator of caries risk. An increase in the numbers of patients at risk for the development of dental caries was seen at the 2 month sample collection point. Thereafter, the number of patients at risk decreased, so that at completion of the study, the number of patients at risk for caries development was down to near that observed prior to treatment. Fermentation reactions and PFGE analyses were completed for all baseline saliva samples, and all 4 month saliva, tooth plaque, and appliance plaque samples. Fermentative data indicated that 86/102 (84%) of the samples obtained were Streptococcus mutans, and that there were no Streptococcus sobrinus isolates present. The remaining isolates 14/102 (16%) were not characterized further, and were assumed to be viridans streptococci. Results of PFGE indicated that the same, or no more than two different strains of S. mutans predominated in the saliva and plaque of most of the patients examined.
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    The Effect of Nicotine on Human Lymphocyte IL-6 Production
    (2001) Zhang, Shaobin; Olson, Byron L.; Gregory, Richard L.; Hathaway, Ronald; Shanks, James; Katona, Thomas
    Studies have suggested that the immune system may play important roles in the regulation of bone remodeling through cytokines secreted by inflammatory cells migrating from periodontal ligament capillaries after orthodontic force application. There is evidence that tobacco usage has profound effects on bone metabolism. The mechanism of nicotine on bone metabolism is not fully understood. One possibility may be related to certain cytokines. Cytokines are hormone-like molecules. They are important in regulating the development of the immune system and mediating immune responses. Interleukin 6 is an important cytokine secreted by activated T cells. IL-6 is a multifunctional interleukin with significant effects on different cell types. IL-6 can regulate the development and function of osteoblasts and osteoclasts, and thus play important roles in bone remodeling during orthodontic tooth movement. Nicotine is the major pharmacological component of tobacco. It can exert effects directly on lymphocytes by signaling through nicotinic acetylcholine receptors. Nicotine has profound effects on cytokine production in the immune system. The effect of nicotine on T cell IL-6 production may have an important impact on bone remodeling. However, the effects of nicotine on human T cell IL-6 production have not been extensively studied. The purpose of this study was to determine whether nicotine affects T cell proliferation and IL-6 production by activated T cells. Also the effect of nicotine on T cell activation was studied. The H9 cell line derived from a human cutaneous T cell lymphoma was used as the human T cells in this study. 2x106/ml T cells cultured with different mitogens were stimulated with nicotine for 24, 48, and 72 hr. The chosen nicotine concentrations were 0; 1; 10; 100; 1,000; 3,000; and 10,000 ug/ml. The effects of nicotine on T cell proliferation, T cell metabolic activity, and IL-6 production were studied. Also, the effects of different mitogens on T cell activation were studied. The results demonstrated that high concentrations of nicotine (1,000; 3,000; and 10,000 ug/ml) significantly decreased T cell proliferation, T cell metabolic activity, and IL-6 production. A medium concentration of nicotine (100 ug/ml) slightly increased IL-6 production. This study also demonstrated that TP A is essential in induction of IL-6 from activated T cells. PHA has synergistic effects on TPA induced IL-6 production. ConA, PHA, PHA+ IL β and nicotine did not induce IL-6 production from T cells. Signal transduction is probably involved in this complex process. The results of this study suggested that nicotine has adverse effects on T cell functions.