Determination of dimenhydrinate in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a relative bioavailability study

Here we present a sensitive and specific liquid chromatography-tandem mass spectrometric method for the quantification of dimenhydrinate (I) in human plasma. Sample preparation is conducted using citalopram (II) addition as an internal standard (IS), liquid-liquid extraction with basified plasma using a mixture hexane/acetate (1:1, v/v) as the extracting solvent, and the final extract reconstituted in the mobile phase. I and II (IS) were injected in a C8 column with the mobile phase composed of methanol:isopropanol:water:formic acid (78.00:19.92:2.00:0.08, v/v/v/v) and monitored using a positive electrospray source with tandem mass spectrometry analyses. The selected reaction monitoring (SRM) was set using precursor ion and product ion combinations of m/z 256.0>167.0 and m/z 325.0>109.0 for I and II, respectively. The limit of quantification (LOQ) was 0.4 ng/mL, the dynamic range being 0.4-200 ng/mL. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of plasma samples taken up to 24 h after oral administration of 100 mg of dimenhydrinate in healthy volunteers demonstrated its applicability to bioavailability studies.     

Hepatic-dependent and -independent insulin actions are impaired in the obese Zucker rat model

Objective: Whole‐body insulin sensitivity (IS) depends on a hepatic pathway, involving parasympathetic activation and hepatic nitric oxide (NO) production. Both atropine and N‐monomethyl‐l ‐arginine (l ‐NMMA, NO synthase inhibitor) induce insulin resistance (IR). IR is associated with obesity. Because NO action was shown to be impaired in animal models of obesity, such as the obese Zucker rat (OZR), we tested the hypothesis that the hepatic‐dependent pathway is diminished in OZR, resulting in IR. Research Methods and Procedures: Lean Zucker rats (LZRs) were used as OZR controls. IS was evaluated in terms of glucose disposal [milligrams of glucose per kilogram of body weight (bw)]. Two groups were submitted to two protocols. First, a control clamp was followed by a post‐atropine (3 mg/kg intravenously) clamp. Second, after the control clamp, l ‐NMMA (0.73 mg/kg intraportally) was given, and a second clamp was performed. Hepatic‐dependent IS was assessed by subtracting the response after atropine or l ‐NMMA from the basal response. Results: In the first protocol, basal IS was lower in OZR than in LZR (OZR, 73.7 ± 14.2; LZR, 289.2 ± 24.7 mg glucose/kg bw; p < 0.001), and atropine decreased IS in the same proportion for both groups (OZR, 41.3 ± 8.0%; LZR, 40.1 ± 6.5%). Equally, in the second protocol, OZR presented lower IS (OZR, 79.3 ± 1.6; LZR, 287.4 ± 22.7 mg glucose/kg bw; p < 0.001). l ‐NMMA induced IS inhibition in both groups (OZR, 48.3 ± 6.6%; LZR, 46.4 ± 4.1%), similar to that after atropine. Discussion: We show that the IR in OZR is due to similar impairment of both hepatic‐dependent and ‐independent components of insulin action, suggesting the existence of a defect common to both pathways.     

Reproduction of Blue-black Grassquits in central Brazil.

During the reproductive season Blue-black grassquit (Volatinia jacarina) males are found in clusters, wherein they exhibit a distinctive display that consists of repeated, vertical leaps while simultaneously producing a brief vocalization. The main objective of this study was to describe details of the species' reproductive behavior in a "Cerrado" area of central Brazil and compare these data with some studies carried out in other areas. The data obtained concerning different aspects of nesting, laying and hatching were generally similar to those obtained in previous studies in other areas. However, we found that the typical clutch size of two eggs per nest is lower, and egg and nestling mortality rates higher in our area than what has been reported elsewhere. Our results suggest that males differ in time expended with different activities according to their reproductive condition and also provide extensive parental care. We found that display execution rates peak in the early morning and in the late afternoon and are higher in the middle of the breeding season. We also found that there is an inverse relation between the height of the display leap and the height of the perch.     

Agrometeorological parameters for prediction of the maturation period of Arabica coffee cultivars

The objective of this study was to determine the harvest period of coffee fruits based on the relationship between agrometeorological parameters and sucrose accumulation in the seeds. Over the crop years 2004/2005 and 2006/2007, from 150 days after flowering (DAF) onwards, samples of 50 fruits of cultivars Mundo Novo IAC 376-4, Obat? IAC 1669-20 and Catuaí Vermelho IAC 144 were collected from coffee trees located in Campinas, Brazil. The endosperm of the fruits was freeze-dried, ground and analyzed for sucrose content by high-performance liquid chromatography. A weather station provided data to calculate the accumulated growing degree-day (GDD) units, and the reference (ET(o)) and actual (ET(r)) evapotranspiration rates. The results showed that the highest rates of sucrose accumulation occurred at the transition from the cane-green to the cherry phenological stage. Models for the estimation of sucrose content during maturation based on meteorological variables exhibited similar or better performance than the DAF variable, with better results for the variables GDD and ET(o). The Mundo Novo cultivar reached the highest sucrose level in the endosperm after 2,790 GDD, while cultivar Catuaí attained its maximum sucrose concentration after the accumulated evapotranspiration rate has reached a value of 870 mm. As for cultivar Obat?, the maximum sucrose concentration was predicted with the same degree of accuracy using any of the parameters investigated. For the Obat? cultivar, the values of the variables calculated for the maximum sucrose concentration to be reached were 249 DAF, 3,090 GDD, 1,020 ET(o) and 900 ET(r).     

Hyaluronic acid depolymerization by ascorbate-redox effects on solid state cultivation of <Emphasis Type="Italic">Streptococcus zooepidemicus</Emphasis> in cashew apple fruit bagasse

The cashew fruit (Anacardium occidentale L.) has been used as a promising agricultural resource for the production of low-molecular weight (M_W) hyaluronic acid (HA) (10⁴–10⁵ Da). The cashew juice is a rich source of vitamin C containing, 1.2–2.0 g L⁻¹. This work explores the effects of the initial concentration of the ascorbate on the solid fermentation of the juice-moisturized bagasse from the cashew apple fruit. The results show that the M_W reduction of HA is proportional to the initial ascorbate concentration. The presence of ascorbate did not influence the Streptococcus zooepidemicus metabolism. However, the HA productivity was increased from 0.18 to 0.28 mg g⁻¹ h⁻¹ when the ascorbate concentration ranged from 1.7 to 10 mg mL⁻¹. These findings contribute to the controlled production of HA in a low M_W range, which is important in cell signalization, angiogenesis and nanoparticles production.     

Green coconut fiber: a novel carrier for the immobilization of commercial laccase by covalent attachment for textile dyes decolourization

Commercial laccase formulation was immobilized on modified green coconut fiber silanized with 3-glycidoxypropyltrimethoxysilane, aiming to achieve a cheap and effective biocatalyst. Two different strategies were followed: one point (pH 7.0) and multipoint (pH 10.0) covalent attachment. The influence of immobilization time on enzymatic activity and the final reduction with sodium borohydride were evaluated. The highest activities were achieved after 2?h of contact time in all situations. Commercial laccase immobilized at pH 7.0 was found to have higher activity and higher affinity to the substrate. However, the immobilization by multipoint covalent attachment improved the biocatalyst thermal stability at 50?°C, when compared to soluble enzyme and to the immobilized enzyme at pH 7.0. The Schiff's bases reduction by sodium borohydride, in spite of causing a decrease in enzyme activity, showed to contribute to the increase of operational stability through bonds stabilization. Finally, these immobilized enzymes showed high efficiency in the continuous decolourization of reactive textile dyes. In the first cycle, the decolourization is mainly due to dyes adsorption on the support. However, when working in successive cycles, the adsorption capacity of the support decreases (saturation) and the enzymatic action increases, indicating the applicability of this biocatalyst for textile wastewater treatment.     

Analysis of socio-demographic and systemic health factors and the normative conditions of oral health care in a population of the Brazilian elderly

doi: 10.1111/j.1741‐2358.2010.00446.x
Analysis of socio‐demographic and systemic health factors and the normative conditions of oral health care in a population of the Brazilian elderly Objective: To investigate the association of socio‐demographic and systemic health factors according to the normative conditions of oral health care (dental caries, edentulism, periodontal disease and oral mucosal lesion) in elderly individuals. Material and methods: A cross‐sectional study was carried out in a group of elderly with access to community health care (n = 200). The normative conditions of oral health were then investigated according to the WHO and the SB Brazil criteria. Bivariate analyses were evaluated by the chi‐square test and Fisher’s exact test. An estimation of prevalence for the covariates was performed using Poisson’s regression models. Results: The prevalence of edentulism and oral mucosal lesions was detected in 58% and 21.5% of elderly patients, respectively. In the dentate subjects, the prevalence of dental caries and periodontal disease was 51.2% and 20.8%, respectively. Older men and individuals from lower‐income groups exhibited a higher prevalence of dental caries. Elderly women, illiterate individuals, and individuals over the age of 65 years exhibited a higher prevalence of edentulism. Elderly 60–64 years old and those who are employed had a significant association with periodontal disease. Conclusion: Socio‐demographic factors were associated with some notable oral diseases in the elderly.     

In vitro penetration of fresh and vitrified swine oocytes by homologous spermatozoa using different incubation systems

The present study consisted of two experiments. In the first one, ejaculates from four boars were used to compare in vitro penetration (IVP) rates of fresh and vitrified swine oocytes by homologous spermatozoa in four treatments: fresh oocytes in conventional incubation (CO2 incubator) (FC), vitrified oocytes in conventional incubation (VC), fresh oocytes in submarine (bag) incubation (FS) and vitrified oocytes in submarine incubation (VS). The IVP rates for FC, VC, FS and VS were 46.5, 44.3, 36.9 and 33.1%, respectively. Analysis through Chi-square tests identified no differences in IVP rates between FC and VC and between FS and VS (P > 0.05), but IVP rate for FC was greater (P < 0.05) than those for both FS and VS. Besides IVP rate for VC did not differ (P > 0.05) from those for FC and FS, but it was greater than that for VS (P < 0.05). Logistic regression analysis identified differential effects of treatments dependant on individual boars. The second experiment evaluated the influence of semen storage period on the semen quality of the two boars associated with greater IVP rate in the first experiment. Semen quality was estimated by IVP rate using the VC treatment and by the following methods: sperm motility, sperm morphology, hypoosmotic swelling test (HOST) and thermal stress test (TST). According to analysis using Chi-square tests, IVP rate did not differ (P > 0.05), for the first boar, between 0 (100.0%) and 24 h of semen storage (98.1%) nor after 48 and 72 h (66.0 and 59.3%, respectively), but IVP rates were greater during the 0-24 h period compared with the 48-72 h period (P < 0.05). For the second boar, IVP rate at 0 h (50.6%) was greater (P < 0.05) than at 24, 48 and 72 h of semen storage (34.3, 28.3 and 24.0%, respectively), with no further differences observed after 24 h (P > 0.05). Logistic regression analysis identified that the effect of storage on IVP rate was influenced by the effect of individual boars. No differences in semen quality during the storage period were identified by conventional methods of semen evaluation, for either boar (P > 0.05) using analysis of variance with repeated measures. These results indicate that IVP test can be used to estimate boar fertility, even when vitrified oocytes are used (if using conventional CO2 incubators) or using an alternative submarine incubation system (if using fresh oocytes). The IVP test was the only method of semen evaluation that identified the reduction in semen quality up to 72 h of storage.     

Alterations in Oxidative Markers in the Cerebellum and Peripheral Organs in MPS I Mice

Mucopolysaccharidosis type I is a lysosomal storage disease with alterations in several organs. Little is known about the pathways that lead to the pathology. Evidences point oxidative stress on lysosomal storage diseases and mucopolysaccharidosis type I. The aim of the present study was to evaluate oxidative biomarkers on mucopolysaccharidosis type I mice model. We evaluated antioxidant enzymatic activity, protein damage and lipid peroxidation in the forebrain, cerebellum, heart, lung, diaphragm, liver, kidney and spleen. Superoxide dismutase activity was increased on cerebellum, lung, diaphragm, liver and kidney of mucopolysaccharidosis type I mice. Catalase activity was increased on cerebellum, spleen and lung. There was no alteration on glutathione peroxidase activity on any of the analyzed organs. Mucopolysaccharidosis type I mice showed increased carbonyl groups on cerebellum, heart and spleen. There was a decrease of thiobarbituric acid-reactive substances on the cerebellum of mucopolysaccharidosis type I mice. The results indicate a oxidative imbalance in this model. As lysosomes are very susceptible to oxidative damage, leading inclusive to cellular death, and lysosomal storage diseases present several alterations on this organelles, this finding can help to elucidate the cellular damage pathways on mucopolysaccharidosis type I.