Biomedical subjects
Publications and source records attributed to J Charon.
After having defined the conditions that will start the loss of attached gingiva, the author develops the characteristic of the patient at periodontal risk. He then explains the value of the interview as well as that of the clinical and microbiological exams, insisting on the therapeutic outcome of those exams, and on the effect of the flora.
The effectiveness of an ideal antimicrobial agent depends on its ability to kill microbes with minimal toxicity to host cells. Depending on the treatment regimen, antimicrobial agents come into contact with host cells for various intervals of time. Sanguinarium (SANG), chlorhexidine (CHX) and tetracycline (TET) are 3 antimicrobial agents frequently used in the management of periodontal infections. However, their effects on host immune cells during different treatment regimens are not known. Due to their ability to serve as the first line of host defense against microbial infections, we have compared the effects of these antimicrobial agents on human neutrophil functions and viability. The results show that SANG is not lytic to neutrophils from peripheral blood or crevicular fluid, at all concentrations tested. However, exposures of neutrophils to very low concentrations of SANG (0.001%) inhibits neutrophil chemotaxis, oxidative metabolism and degranulation within 5 min. Increasing the exposure time results in a similar inhibition of neutrophil functions, albeit at 50-100 fold lower concentrations of SANG. CHX rapidly disrupts the cell membrane of both crevicular and peripheral blood neutrophils at concentrations above 0.005% within 5 min, and inhibition of all neutrophil functions is due to its lytic properties. While TET is least toxic to neutrophils, a dose dependent inhibition of neutrophil functions is dependent on the calcium concentrations of the cellular environment, and is observed only above 0.04% or higher concentrations in the absence of calcium. The data suggest that a critical cumulative concentration of these drugs is essential for their toxicity and inhibition of neutrophil functions. Therefore, both the length of exposure and the dose of the drug both are critical while considering the effectiveness of SANG, CHX or TET in the treatment of infections. Furthermore, due to differences in their mechanisms of action, the consequences of their effects on neutrophils may have significant bearing on tissue pathology as well as on their therapeutic efficacy.
Polymorphonuclear neutrophils (PMN) are the predominant cell type in the established lesion of recurrent aphthous stomatitis (RAS). The function of these cells was studied in 15 patients with RAS and 15 age and sex matched controls. Production of oxygen radicals was assessed using cytochrome-c and nitroblue tetrazolium dye (NBT) reduction assays. Oxidative metabolism was found to be similar for experimental and control groups in both stimulated and non-stimulated assays. Adherence to glass surfaces by PMN was also measured. Adherence of PMN, both from patients and controls, was significantly reduced by serum, but to a lesser extent by serum from patients compared to controls. This effect of serum on adherence was reversed by phorbol myristate acetate (PMA) stimulation. These studies suggest that increased adherence of stimulated PMN, due to humoral factors, may be involved in perpetuating ulcerative lesions in RAS.
A placebo-controlled, double-blind study with Ems brine inhalations as postoperative treatment after endoscopic endonasal sinus surgery was conducted on 30 patients. After informed consent had been obtained, the patients were treated with either Ems brine or saline solution (200 ml) 3 times a day for 10 days. The parameters measured were rhinomanometry, X-ray films of the sinuses, endoscopy, saccharin clearance and a subjective evaluation by the physician and by the patient based on a visual analogue scale. The difficulty of choosing parameters for assessing the treatment was that comparable clinical studies and a single predictive parameter were not available. The bacteriological test and the saccharin clearance test were not significantly different between the two groups. Recovery, swelling, crusting, bleeding and signs of inflammation, opacity on sinus X-ray films, and nasal flow as measured by rhinomanometry were all significantly better in the group inhaling brine solution (P less than 0.05).
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The survival rate of Bacteroides intermedius was first tested in monoculture, and Streptococcus sanguis was then added in 5 different transport media; 2 nonnutritious media, the viability-preserving medium of the University of Göteborg No. IV (VMG IV), reduced transport fluid (RTF), and 3 nutritious media, thioglycolate medium (TG), peptone yeast extract medium (PY) and PY medium with 1% glucose (PYG). All manipulations were carried out in an anaerobic chamber. After a given transport time (6 or 24 h) aliquots were spread on plates containing solid PY medium by means of an automated spiral system device, thus permitting counts after incubation. The slight variations in the counts of B. intermedius in monoculture, not exceeding 0.5 log10 in the 5 media tested, indicated its good survival capability, i.e. at least 24 h. By contrast, when S. sanguis was added, it was only possible to use nutritious media such as PY or TG for 6 h. In the glocose-containing media (PYG, TG), the multiplication of rapidly glucose-fermenting microorganisms such as streptococci influenced the B. intermedius survival rate. Therefore, the transport time for oral microbiological samples needs to be reduced as much as possible. The use of excessively rich media (particularly media containing a high level of glucose) should be avoided.
Four groups of mice, each of a different genotype, were orally inoculated with Actinomyces viscosus. The resulting periodontal bone loss was monitored and the isotype specific anti-A. viscosus serum humoral immune responses measured by ELISA. Maximum periodontal bone loss occurred in all genotypes with inoculation of 1.6 x 107 colony forming units of A. viscosus. IgG and IgM isotype levels increased with inoculation of 1.6 x 107 colony forming units of A. viscosus in three of the four groups, indicating that IgA may be important in producing periodontal bone loss.
A case of severe dentinal abrasion most probably due to erroneous use of interproximal brushes is shown and discussed as well.
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