Influence of enamel thickness on quantification of mineral loss in enamel using laser-induced fluorescence

The objective of this study was to evaluate the effect of enamel thickness on the quantification of white-spot lesions with laser fluorescence. One hundred and twenty 3-mm-diameter human ground and polished enamel specimens were used. Specimens were illuminated by a 488-nm argon laser, images were acquired through a 540-nm high-pass filter and stored on the Quantitative Light-Induced Fluorescence (QLF) program. Specimens were divided into two groups and demineralized for 48 or 96 h and QLF images were again acquired. Fluorescence radiance (FR) of both sound (FR(s)) and demineralized (FR(d)) enamel was determined using the QLF program. Change in fluorescence radiance (Delta FR, %) was determined as follows: Delta FR = FR(d)/FR(s) x 100. One thin section was obtained for transverse microradiography analysis. Enamel and dentin thickness of the thin sections were measured. There was a good correlation between QLF parameters and enamel thickness. It can be concluded that the FR observed for similar lesions depends on the actual enamel thickness.     

Heat shock protein of Mycoplasma salivarium and Mycoplasma orale strains isolated from HIV-seropositive patients

It has been suggested that infection by some mycoplasma species can act as possible cofactors in the acceleration of immunodeficiency in HIV-infected patients. The present study was designed to examine infections by oral mycoplasma species in HIV-seropositive (HIV(+)) patients. Mycoplasma salivarium and Mycoplasma orale were isolated from 59.5% and 16.7% of 42 HIV(+) patients, respectively. Non-M. salivarium and non-M. orale species were isolated from 40.5% of saliva samples from the HIV(+) group and 20.8% of those from 24 HIV-seronegative (HIV(-)) subjects, respectively. Although the production of superantigen by human peripheral lymphocytes in the isolated mycoplasma species from HIV(+) and HIV(-) subjects was evaluated, none of the examined mycoplasma strains, including ATCC strains of M. salivarium, M. orale, Mycoplasma buccae and Mycoplasma penetrans, were found to produce superantigen. Production of heat shock proteins (HSPs) by isolated mycoplasma strains was examined by immunoblotting using monoclonal antibodies against Helicobacter pylori HSP60. It was found that all the strains of M. salivarium, M. orale, and unidentified mycoplasma species isolated from HIV(+) and HIV(-) groups produced heat shock proteins. HSP production by oral mycoplasma may play a role in the immunomodulation of HIV(+) patients.     

Covariates of tooth-brushing frequency in low-income African Americans from grades 5 to 8

PURPOSE: The purpose of this study was to examine tooth-brushing frequency in 575 urban and nearby suburban African American children as part of a comprehensive risk-reduction study for students at high risk for violence, drugs, school delinquency, and unsafe sexual behaviors to determine which covariates predicted tooth-brushing frequency. METHODS: Students were surveyed 5 times, from the beginning of grade 5 and the end of each year through grade 8, and parents were surveyed at the beginning of grade 5. Peer influence, importance of being liked, self-esteem, attitudes towards tooth-brushing, oral health knowledge, self-efficacy, parental attitudes, and other covariates were examined for the ability to predict self-reporting of tooth-brushing frequency. RESULTS: In the fifth grade, peer influence, the importance of being liked, and physical self-esteem were the significant predictors, and peer influence continued to predict tooth-brushing in the eighth grade. Oral health knowledge and parental influence were not significant. CONCLUSION: Peer influence is an important factor in tooth-brushing behavior in metropolitan African American preadolescent children.     

Antimicrobial effect of triclosan and triclosan with Gantrez on five common endodontic pathogens

Microbial control of the root canal system is one of the key objectives of root canal therapy. Triclosan is a widely accepted broad spectrum antimicrobial agent proven to be effective against many gram-positive and gram-negative bacteria. Triclosan acts by blocking bacterial fatty acid biosynthesis. The addition of Gantrez copolymer has been shown to enhance the antimicrobial activity of triclosan. The purpose of this study was to determine the minimum inhibitory and bactericidal concentrations of triclosan and triclosan with Gantrez against Prevotella intermedia, Fusobacterium nucleatum, Actinomyces naeslundii, Porphyromonas gingivalis, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) of both test solutions was determined for each of the 5 microorganisms by using microtiter serial dilutions. Samples were streaked on 5% sheep blood agar plates and placed in an anaerobic incubator to determine the minimum bactericidal concentration (MBC). The MBC of triclosan ranged from 12-94 microg/mL. The MBC of triclosan with Gantrez ranged from <0.3-10.4 microg/mL. The addition of Gantrez enhanced the bactericidal activity of triclosan. Both triclosan and triclosan with Gantrez demonstrated bactericidal activity against the 5 specific endodontic pathogens.     

Comparison of different methods involved in the planning of clinical crown lengthening surgery

There is little material in the literature that compares biological width measurements in periapical and bite-wings radiographs with clinical measurements. The purpose of this study was to compare measurements of biological width taken by three different methods which are frequently used for planning periodontal surgery - periapical radiograph, bite-wing radiograph and transperiodontal probing - with the trans-surgical measurements. Thirty-four sites from twenty-one subjects were analyzed. The intra-class correlation coefficients between measurements obtained trans-surgically (gold standard) and those obtained by transperiodontal probing, periapical radiography and bite-wing radiography were determined. Average measurements were compared using the Wilcoxon test at a significance level of 0.05. Also, the frequency distribution of differences between test measurements and the gold standard was calculated. The results showed that transperiodontal probing (mean 2.05 mm) was the most accurate measurement, as compared to the gold standard (mean 1.97 mm), with no statistically significant difference observed. On the other hand, periapical and bite-wing radiographic mean values (1.56 mm and 1.72 mm, respectively) were smaller than the gold standard, with statistically significant differences (p < 0.05). It was concluded that transperiodontal probing was the most accurate measurement, as compared to the gold standard, followed by that obtained with the bite-wing radiograph. The clinical relevance of these results could be that planning for crown lengthening surgery should, preferably, include transperiodontal probing.     

Tumor-induced mechanical hyperalgesia involves CGRP receptors and altered innervation and vascularization of DsRed2 fluorescent hindpaw tumors

Functional and anatomical relationships among primary afferent fibers, blood vessels, and cancers are poorly understood. However, recent evidence suggests that physical and biochemical interactions between these peripheral components are important to both tumor biology and cancer-associated pain. To determine the role of these peripheral components in a mouse model of cancer pain, we quantified the change in nerve and blood vessel density within a fibrosarcoma tumor mass using stereological analysis of serial confocal optical sections of immunostained hind paw. To this end we introduced the Discoma coral-derived red fluorescent protein (DsRed2) into the NCTC 2472 fibrosarcoma line using the Sleeping Beauty transposon methodology, thus providing a unique opportunity to visualize tumor-nerve-vessel associations in context with behavioral assessment of tumor-associated hyperalgesia. Tumors from hyperalgesic mice are more densely innervated with calcitonin gene related peptide (CGRP)-immunoreactive nerve fibers and less densely vascularized than tumors from non-hyperalgesic mice. As hyperalgesia increased from Day 5 to 12 post-implantation, the density of protein gene product 9.5 (PGP9.5)-immunoreactive nerves and CD31-immunoreactive blood vessels in tumors decreased, whereas CGRP-immunoreactive nerve density remained unchanged. Importantly, intra-tumor injection of a CGRP1 receptor antagonist (CGRP 8-37) partially blocked the tumor-associated mechanical hyperalgesia, indicating that local production of CGRP may contribute to tumor-induced nociception through a receptor-mediated process. The results describe for the first time the interaction among sensory nerves, blood vessels and tumor cells in otherwise healthy tissue, and our assessment supports the hypothesis that direct tumor cell-axon communication may underlie, at least in part, the occurrence of cancer pain.     

Acute effects of hyperglycemia and hyperinsulinemia on hepatic oxidative stress and the systemic inflammatory response in rats

OBJECTIVES: Intensive blood glucose control to a target value of 80-110 mg/dL has been shown to reduce morbidity and mortality in surgical intensive care unit patients. This was attributed predominantly to correction of hyperglycemia, based on multivariate regression analysis. However, the effects of glucose and insulin have not been independently evaluated. This study investigated the development of hepatic oxidative processes and systemic inflammatory response in rats with different levels of induced hyperglycemia and hyperinsulinemia. The effects of a modest increase in blood glucose following glucose infusion at a level adequate to meet energy requirements, hyperinsulinemia induced by a hyperinsulinemic euglycemic clamp with administered glucose in similar amounts, and marked hyperglycemia and hyperinsulinemia secondary to glucose infusion on hepatic oxidative stress and systemic inflammatory response in vivo were examined. DESIGN: Controlled laboratory study. SETTING: Medical school laboratory. SUBJECTS: Specific pathogen-free male Sprague-Dawley rats. INTERVENTIONS: Blood glucose was monitored over 3 hrs. At the end of study, the serum concentrations of insulin, tumor necrosis factor-alpha, interleukin-1, and alpha1 acid glycoprotein were determined. Malondialdehyde and total glutathione content were measured in the liver. MEASUREMENTS AND MAIN RESULTS: Glucose infusion adequate to provide energy requirements resulted in a modest increase in blood glucose (143+/-8 mg/dL) and hyperinsulinemia (45 microU/mL) and did not induce measurable hepatic oxidative stress or systemic inflammation. A hyperinsulinemic euglycemic clamp (insulin 112+/-9 microU/mL) resulted in evidence of increased oxidative processes in the liver but no change in hepatic antioxidant capacity or evidence of systemic inflammation. When hyperglycemia (approximately 350 mg/dL) and hyperinsulinemia (167+/-9 microU/mL) were induced by excess glucose infusion, rats manifested hepatic oxidative stress, antioxidant depletion, and a mild systemic inflammatory response. CONCLUSIONS: Hyperglycemia is a major cause of the systemic inflammatory response. Maintaining normal blood glucose, by avoiding overfeeding and providing insulin therapy when necessary, appears key to minimizing oxidative stress and systemic inflammation when intravenous nutrition is provided.     

Cefaclor revisited

OBJECTIVE: This paper describes the rationale for choosing cefaclor for the management of respiratory tract infections. BACKGROUND: Since 1979, cefaclor has established a record of efficacy in the management of respiratory tract infections. Factors contributing to the efficacy and tolerability of this drug include its molecular stability, activity against the most prevalent gram-positive and gram-negative respiratory tract pathogens, rapid absorption, >90% bioavailability, and good penetration into respiratory mucosa. After 2 decades of widespread use, this agent remains clinically effective in patients with respiratory tract infections, making it competitive with other cephalosporins and with macrolides and fluoroquinolones, including many newer agents used for respiratory tract infections. Cefaclor extended-release tablets, the newest formulation, retain the positive efficacy and tolerability attributes of immediate-release cefaclor, varying mainly in the rate of dissolution. The approved indications for extended-release cefaclor include bacterial bronchitis, pharyngitis, and skin infections. METHODS: A MEDLINE search showed that the few adverse effects related to therapy with cefaclor are usually minor and transient and that drug-drug interactions involving cefaclor are rare. CONCLUSIONS: Multiple clinical trials have shown that extended-release cefaclor in 375-mg and 500-mg doses BID demonstrates tolerability and efficacy comparable to those of immediate-release cefaclor 250 mg TID. Extended-release cefaclor is indicated for BID dosing, which should encourage greater compliance.     

Tidal breathing flow-volume loops in bronchiolitis in infancy: the effect of albuterol [ISRCTN47364493]

Objectives  

To evaluate the effect of nebulized albuterol on tidal breathing flow-volume loops in infants with bronchiolitis due to respiratory syncytial virus.