Insulin sensitivity in response to a single resistance exercise session in apparently healthy individuals

BACKGROUND: Regular resistance exercise completed for a number of weeks has been shown to increase insulin sensitivity and reduce the risk of diabetes-related complications. However, the acute responses to resistance exercise have not been adequately investigated in relation to training frequency.
AIM: To investigate the changes to insulin sensitivity in apparently healthy individuals following a single session of unaccustomed resistance exercise.
SUBJECTS AND METHODS: Ten sedentary, apparently healthy individuals performed a baseline oral glucose tolerance test and maximal strength testing. Participants then performed a single session of moderate-high intensity resistance exercise which was followed by 4 consecutive days of oral glucose tolerance testing, for which participants replicated their initial diet. Mean estimated insulin sensitivity change scores from baseline values and their 95% confidence intervals were compared to the previously determined values for a clinically meaningful change.
RESULTS: Two participants were identified as having hyperinsulinemia and their data were therefore removed from the main analysis. There was a clinically meaningful increase in insulin response (mean >7237 pmol·l⁻¹·120 min⁻¹) on all days following the exercise session and a clinically meaningful increase in glucose response (mean >81 mmol·l⁻¹·120 min⁻¹) on only the 3rd day following exercise. These changes suggest a potentially adverse short-term effect. Additionally, the 2 individuals with hyperinsulinemia displayed more extreme results.
CONCLUSION: These results suggest that insulin sensitivity may be impaired following a single session of unaccustomed resistance exercise for approximately 4 days in healthy untrained, older individuals. Further research is required for individuals with hyperinsulinemia

Ascorbic acid supplementation improves skeletal muscle oxidative stress and insulin sensitivity in people with type 2 diabetes: findings of a randomized controlled study

AIM/HYPOTHESIS: Skeletal muscle insulin resistance and oxidative stress are characteristic metabolic disturbances in people with type 2 diabetes. Studies in insulin resistant rodents show an improvement in skeletal muscle insulin sensitivity and oxidative stress following antioxidant supplementation. We therefore investigated the potential ameliorative effects of antioxidant ascorbic acid (AA) supplementation on skeletal muscle insulin sensitivity and oxidative stress in people with type 2 diabetes. METHODS: Participants with stable glucose control commenced a randomized cross-over study involving four months of AA (2×500mg/day) or placebo supplementation. Insulin sensitivity was assessed using a hyperinsulinaemic, euglycaemic clamp coupled with infusion of 6,6-D2 glucose. Muscle biopsies were measured for AA concentration and oxidative stress markers that included basal measures (2',7'-dichlorofluorescin [DCFH] oxidation, ratio of reduced-to-oxidized glutathione [GSH/GSSG] and F2-Isoprostanes) and insulin-stimulated measures (DCFH oxidation). Antioxidant concentrations, citrate synthase activity and protein abundances of sodium-dependent vitamin C transporter 2 (SVCT2), total Akt and phosphorylated Akt (ser473) were also measured in muscle samples. RESULTS: AA supplementation significantly increased insulin-mediated glucose disposal (delta rate of glucose disappearance; ∆Rd) (p=0.009), peripheral insulin-sensitivity index (p=0.046), skeletal muscle AA concentration (p=0.017) and muscle SVCT2 protein expression (p=0.008); but significantly decreased skeletal muscle DCFH oxidation during hyperinsulinaemia (p=0.007) when compared with placebo. Total superoxide dismutase activity was also lower following AA supplementation when compared with placebo (p=0.006). Basal oxidative stress markers, citrate synthase activity, endogenous glucose production, HbA1C and muscle Akt expression were not significantly altered by AA supplementation. CONCLUSIONS/INTERPRETATION: In summary, oral AA supplementation ameliorates skeletal muscle oxidative stress during hyperinsulinaemia and improves insulin-mediated glucose disposal in people with type 2 diabetes. Findings implicate AA supplementation as a potentially inexpensive, convenient, and effective adjunct therapy in the treatment of insulin resistance in people with type 2 diabetes.

Repeated exposure of adolescent rats to oral methylphenidate does not induce behavioral sensitization or cross-sensitization to nicotine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da expressão da BMP -2/4 e BMPR-IA em Carcinoma Epidermóide Oral metastático e não metastático

The expression of bone morphogenetic proteins (BMPs) is altered in a variety of human canceres. The BMP-2/4 and BMPR-IA were recently shown to be overexpressed in high-risk premalignant and malignant lesions of oral epithelium. The present study analysed the expression of BMP-2/4 and BMPR-IA in Oral Squamous Cell Carcinoma (OSCC) such as their implications in disease prognostic using munohistochemistry. Ten cases of Oral Fibroepithelial Hiperplasia were selected as a control group. The experimental group included 16 cases of OSCC without metastases and 7 cases of OSCC metastatic. The presence or absence of nodal metastases was used as parameter to evaluated the disease prognostic. The results demonstrated weak immunoreactivity for BMP-2/4 and BMPR-IA in every case of the control group. In the cases of OSCC with metastases an overexpression of BMP-2/4 (71,4%) was observed while the BMPR-IA showed weak expression (85,7%). In the cases of OSCC without metastases BMP-2/4 (62,5%) and BMPR-IA showed strong immunostaining standing out an overexpression of the receptor in all the specimens. Observed statistical significance for correlation between the oral cancer prognostic and the staining intensity of the BMP-2/4 (p=0,002). There wasn t statistical significance for association between the staining intensity of the BMPR-IA and the disease prognostic (p<0,001). In conclusion, this findings suggest that the overexpression of BMP-2/4 associated with the loss of expression of the BMPR-IA in OSCC metastatic has prognostic relevance, as the loss of sensitivity to BMPs can be an indicative of metastases development in OSCC

Estudo de alterações na cavidade oral em pacientes com doença do refluxo gastroesofágico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Enrofloxacin assay validation and pharmacokinetics following a single oral dose in chickens

The pharmacokinetics of enrofloxacin (ENRO), a fluoroquinolone antimicrobial agent, was studied in male broiler chickens (Cobb) after single oral administration of 10 mg of ENRO/kg b.w. A high-performance liquid chromatography-photodiode array detector (DAD) (HPLC-DAD) method was developed and validated and used for quantitation of ENRO and its major metabolite ciprofloxacin in plasma. The HPLC analyses were carried out using a cationic-octadecyl mixed column and 0.05 mol/L phosphate buffer (pH 2.5)/acetonitrile as mobile phase. The sample preparation of plasma consisted of the precipitation of proteins followed by solid phase extraction on cationic-octadecyl mixed cartridges. The method was validated considering linear range, linearity, selectivity, sensitivity, limit of detection (LOD), limit of quantitation (LOQ), intra- and inter-day precisions and accuracy. The LOD and LOQ for both fluoroquinolones were 60 and 200 ng/mL for plasma. The plasma concentration vs. time graph was characteristic of a two-compartment open model. The maximal plasma concentration of 1.5 +/- 0.2 mg/mL was achieved at 9 +/- 2 h. The elimination half-life and the mean residence time of ENRO were 1.5 +/- 0.2 and 15.64 h, respectively. The area under the concentration-time curve was calculated as 35 +/- 4 mg(.)h/mL.

Reliability of toluidine blue application in the detection of oral epithelial dysplasia and in situ and invasive squamous cell carcinomas

Objective, the objective of this study was to evaluate the reliability of in vivo staining with toluidine blue in the detection of oral epithelial dysplasia, in situ carcinoma, and invasive squamous cell carcinomas in potentially malignant epithelial lesions (PMELs) and superficial oral ulcerations suggesting malignancy.Study design. Fifty patients with PMELs and superficial oral ulcerations suggestive of malignancy were selected from those treated at the Oral Medicine Service, Faculty of Dentistry, Araraquara, Brazil. All lesions were submitted to staining with an aqueous solution of 1% toluidine blue, followed by biopsy and histologic analysis. The sensitivity, specificity, and positive and negative predictive values were calculated.Results. Histologic diagnosis revealed that 14% of the lesions analyzed were in situ carcinoma and invasive squamous cell carcinomas, 12% were epithelial dysplasias, 13% were keratosis, 40% were lichen planus, and 8% were other benign lesions. The sensitivity uf the staining was 77%, the specificity 67%, and the positive and negative predictive values 43.5% and 88.9%, respectivelyConclusions, Staining with toluidine blue was demonstrated to be highly reliable in the detection of in situ carcinoma acid invasive squamous cell carcinoma, because false-negative results for the lesions did not occur. Toluidine blue staining is an adjunct to clinical judgment and not a substitute for either judgment or biopsy.

Accurate Approach in the Treatment of Oral Bisphosphonate-Related Jaw Osteonecrosis

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is not completely understood and difficult to treat. Even though the occurrence of BRONJ is mainly related to the therapy with intravenous bisphosphonates (BPs), this article reports a case of long-term oral BP use and BRONJ occurrence. In addition, a literature review provides some additional information about BPs, BRONJ, and also a guideline for the prevention and treatment of BRONJ stages. A 79-year-old patient presented intense and persistent pain, purulent secretion, and exposed bone at the right side of the lower jaw. Thus, she was submitted to anamnesis, radiologic and tomographic examinations, and bacterial culture and sensitivity tests. These procedures were followed by surgical debridement of the bone and surrounding tissues/cyst and antibiotic prescription and histopathologic analysis of the fragments. Together, the examinations performed showed the occurrence of stage 2 BRONJ. Moreover, the antibiotic prescription, discontinuation of oral BP, and surgical procedures ensure that the patient had no more symptoms. Therefore, considering the presented case, we believe that an accurate approach is promising to diagnose and treat stage 2 BRONJ and other associated pathologic findings.

Reproducibility and validity of self-perceived oral health conditions

The reproducibility and validity of self-perceived periodontal, dental, and temporomandibular joint (TMJ) conditions were investigated. A questionnaire was applied in interview to 200 adults aged from 35 to 44, who were attending as casual patients at Araraquara School of Dentistry, Sauo Paulo State University, Sauo Paulo, Brazil. Clinical examination was based on the guidelines of the World Health Organization manual. The interview and the clinical examination were performed in two occasions, by a calibrated examiner. Reproducibility and validity were, respectively, verified by kappa statistics (kappa) and sensitivity (Sen) and specificity (Spec) values, having clinical examination as the validation criterion. The results showed an almost perfect agreement for self-perceived TMJ (kappa=0.85) and periodontal conditions (kappa=0.81), and it was substantial for dental condition (kappa=0.69). Reproducibility according to clinical examination showed good results (kappa=0.73 for CPI index, kappa=0.96 for dental caries, and kappa=0.74 for TMJ conditions). Sensitivity and specificity values were higher for self-perceived dental (Sen=0.84, Spec=1.0) and TMJ conditions (Sen=1.0, Spec=0.8). With regard to periodontal condition, specificity was low (0.43), although sensitivity was very high (1.0). Self-perceived oral health was reliable for the examined conditions. Validity was good to detect dental conditions and TMJ disorders, and it was more sensitive than specific to detect the presence of periodontal disease.

Relative contributions of beta-cell function and tissue insulin sensitivity to fasting and postglucose-load glycemia

We performed hyperglycemic clamps in 283 nondiabetic Caucasians and, with multiple linear regression, determined the contribution of beta-cell function and tissue insulin sensitivity to variations in glycemia and insulinemia during oral glucose tolerance tests (OGTTs). Impaired glucose tolerance (IGT) subjects had reduced insulin sensitivity(P < .02) and beta-cell function (P < .0001). Normal glucose tolerance (NGT) subjects with first-degree type 2 diabetic relatives had reduced first and second phase insulin secretion (both, P < .05), but normal insulin sensitivity(P = .37). beta-Cell function and insulin sensitivity accounted for one fourth of the variability in glucose tolerance. Fasting plasma glucose in subjects with NGT (n = 185) was a function of both phases of insulin secretion and of insulin sensitivity tall, P < .05), whereas, in IGT subjects (n = 98), it was a function of first phase insulin secretion and insulin sensitivity(P < .01). Two-hour glycemia was a function of second phase secretion and insulin sensitivity (P < .01). Fasting and 2-hour plasma insulin levels were determined by insulin sensitivity land glycemia) in NGT subjects (P < .001), but by second phase secretion in IGT (P < .001). We conclude that beta-cell function is reduced in subjects with IGT; glycemia and insulinemia are not regulated by the same mechanisms in IGT and NGT; insulin sensitivity does not contribute to insulinemia in IGT; family history of diabetes influences beta-cell function, but not insulin sensitivity in Caucasians. Copyright (C) 2000 by W.B. Saunders Company.

Antimicrobial activity of Uncaria tomentosa against oral human pathogens

Uncaria tomentosa is considered a medicinal plant used over centuries by the peruvian population as an alternative treatment for several diseases. Many microorganisms usually inhabit the human oral cavity and under certain conditions can become etiologic agents of diseases. The aim of the present study was to evaluate the antimicrobial activity of different concentrations of Uncaria tomentosa on different strains of microorganisms isolated from the human oral cavity. Micropulverized Uncaria tomentosa was tested in vitro to determine the minimum inhibitory concentration (MIC) on selected microbial strains. The tested strains were oral clinical isolates of Streptococcus mutans, Staphylococcus spp., Candida albicans, Enterobacteriaceae and Pseudomonas aeruginosa. The tested concentrations of Uncaria tomentosa ranged from 0.25-5% in Müeller-Hinton agat. Three percent Uncaria tomentosa inhibited 8% of Enterobacteriaceae isolates, 52% of S. mutans and 96% of Staphylococcus spp. The tested concentrations did not present inhibitory effect on P. aeruginosa and C. albicans. It could be concluded that micropulverized Uncaria tomentosa presented antimicrobial activity on Enterobacteriaceae, S. mutans and Staphylococcus spp. isolates.

Influence of lower cutoff values for 100-g oral glucose tolerance test and glycemic profile for identification of pregnant women at excessive fetal growth risk

Objective: To evaluate data from patients with normal oral glucose tolerance test (OGTT) results and a normal or impaired glycemic profile (GP) to determine whether lower cutoff values for the OGTT and GP (alone or combined) could identify pregnant women at risk for excessive fetal growth. Methods: We classified 701 pregnant women with positive screening for gestational diabetes mellitus (GDM) into 2 categories - (1) normal 100-g OGTT and normal GP and (2) normal 100-g OGTT and impaired GP - to evaluate the influence of lower cutoff points in a 100-g OGTT and GP (alone or in combination) for identification of pregnant women at excessive fetal growth risk. The OGTT is considered impaired if 2 or more values are above the normal range, and the GP is impaired if the fasting glucose level or at least 1 postprandial glucose value is above the normal range. To establish the criteria for the OGTT (for fasting and 1, 2, and 3 hours after an oral glucose load, respectively), we considered the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL), mean plus 1 SD (85 mg/dL, 151 mg/dL, 133 mg/dL, and 118 mg/dL), and mean plus 2 SD (95 mg/dL, 182 mg/dL, 153 mg/dL, and 139 mg/dL); and for the GP, we considered the mean and mean plus 1 SD (78 mg/dL and 92 mg/dL for fasting glucose levels and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial glucose levels, respectively). Results: Subsequently, the women were reclassified according to the new cutoff points for both tests (OGTT and GP). Consideration of values, in isolation or combination, yielded 6 new diagnostic criteria. Excessive fetal growth was the response variable for analysis of the new cutoff points. Odds ratios and their respective confidence intervals were estimated, as were the sensitivity and specificity related to diagnosis of excessive fetal growth for each criterion. The new cutoff points for the tests, when used independently rather than collectively, did not help to predict excessive fetal growth in the presence of mild hyperglycemia. Conclusion: Decreasing the cutoff point for the 100-g OGTT (for fasting and 1, 2, and 3 hours) to the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL) in association with the GP (mean or mean plus 1 SD-78 mg/dL and 92 mg/dL for the fasting state and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial values-increased the sensitivity and specificity, and both criteria had statistically significant predictive power for detection of excessive fetal growth. © 2008 AACE.

The in vitro antimicrobial activity of natural infant fluoride-free toothpastes on oral micro-organisms

Purpose: The objective of this study was to evaluate the antimicrobial activity of six toothpastes for infants: 3 fluoride-free experimental toothpastes - cashew-based, mango-based and without plant extract and fluoride compared with 2 commercially fluoride-free toothpastes and 1 fluoridated toothpastes. Methods: Six toothpastes for infants were evaluated in this study: (1) experimental cashew-based toothpaste; (2) experimental mango-based toothpaste; (3) experimental toothpaste without plant extract and fluoride (negative control); (4) First Teeth brand toothpaste; (5) Weleda brand toothpaste; and (6) Tandy brand toothpaste (positive control). The antimicrobial activity was recorded against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus acidophilus, and Candida albicans using the agar plate diffusion test. Results: First Teeth, Weleda, mango-based toothpaste, and toothpaste without plant extract presented no antimicrobial effect against any of the tested micro-organisms. Cashew toothpaste had antimicrobial activity against S mutans, S sobrinus, and L acidophilus, but it showed no antimicrobial activity against C albicans. There was no statistical difference between the inhibition halo of cashew and Tandy toothpastes against S mutans and L acidophilus. Conclusions: Cashew fluoride-free toothpaste had inhibitory activity against Streptococcus mutans and Lactobacillus acidophilus, and these results were similar to those obtained for fluoridated toothpaste.

In vitro susceptibility of oral Candida albicans strains to different pH levels and calcium hydroxide saturated aqueous solution

Candida albicans is present in the oral cavity and in the whole digestive tract of humans and other animals, being frequently related to endodontic treatment failure. The present study determined the incidence of C. albicans in the oral cavity and the susceptibility of isolates to different pH values and saturated calcium hydroxide aqueous solution at pH 12.5. Sixty-five patients attending the Endodontic Clinic at the Sagrado Coração University participated in the study. The collected samples were cultivated in selective media for C. albicans and the isolates were tested in terms of resistance to both alkaline pH and saturated aqueous solution of calcium hydroxide. In relation to time variables, yeast viability was assessed by the Sabouraud's agar culture and fluorescein diacetate and ethidium bromide fluorescent staining method. Results from the different pHs and experimental times, including those from different techniques measuring fungal viability, were compared using the chi-square and Fisher's exact tests (α=0.05). The yeasts became completely inviable after 48 h of contact with the calcium hydroxide solution. On the other hand, when exposed to the alkaline culture broth, the yeasts were found to be viable at pHs 9.5 and 10.5 for up to 7 days. In conclusion, C. albicans can only be completely inhibited by direct contact with saturated calcium hydroxide aqueous solution after 48 h of exposure.