Hemolymph ionic regulation and adjustments in gill (Na(+), K(+))-ATPase activity during salinity acclimation in the swimming crab Callinectes ornatus (Decapoda, Brachyura)

We evaluate hemolymph osmotic and ionic regulatory abilities and characterize a posterior gill microsomal (Na(+), K(+))-ATPase from the marine swimming crab, Callinectes ornatus, acclimated to 21 parts per thousand or 33 parts per thousand salinity. C ornatus is isosmotic after acclimation to 21 parts per thousand but is hyposmotic at 33 parts per thousand salinity; hemolymph ions do not recover initial levels on acclimation to 21 parts per thousand salinity but are anisoionic compared to ambient concentrations, revealing modest regulatory ability. NH(4)(+) modulates enzyme affinity for K(+), which increases 187-fold in crabs acclimated to 33%. salinity. The (Na(+), K(+))-ATPase redistributes into membrane fractions of different densities, suggesting that altered membrane composition results from salinity acclimation. ATP was hydrolyzed at maximum rates of 182.6 +/- 7.1 nmol Pi min(-1) mg(-1) (21 parts per thousand) and 76.2 +/- 3.5 nmol Pi min(-1) mg(-1) (33 parts per thousand), with little change in K(M) values (approximate to 50 mu mol L(-1)). K(+) together with NH(4)(+) synergistically stimulated activity to maximum rates of approximate to 240 nmol Pi min(-1) mg(-1). K, values for ouabain inhibition (approximate to 110 mu mol L(-1)) decreased to 44.9 +/- 1.0 mu mol L(-1) (21 parts per thousand) and 28.8 +/- 1.3 mu mol L(-1) (33 parts per thousand) in the presence of both K(+) and NH(4)(+). Assays employing various inhibitors suggest the presence of mitochondrial F(0)F(1)- and K(+)- and V-ATPase activities in the gill microsomes. (C) 2009 Elsevier Inc. All rights reserved.

Na(+), K(+)-ATPase activity in gill microsomes from the blue crab, Callinectes danae, acclimated to low salinity: Novel perspectives on ammonia excretion

This investigation provides an extensive characterization of the modulation by ATP, Mg(2+), Na(+), K(+) and NH(4)(+) of a gill microsomal (Na(+),K(+))-ATPase from Callinectes danae acclimated to 15 parts per thousand salinity. Novel findings are the lack of high-affinity ATP-binding sites and a 10-fold increase in enzyme affinity for K(+) modulated by NH4+, discussed regarding NH4+ excretion in benthic marine crabs. The (Na(+),K(+))-ATPase hydrolyzed ATP at a maximum rate of 298.7 +/- 16.7 nmol Pi min(-1) mg(-1) and K(0.5) = 174.2 +/- 9.8 mmol L(-1) obeying cooperative kinetics (n(H) = 1.2). Stimulation by sodium (V = 308.9 +/- 15.7 nmol Pi min(-1) mg(-1), K(0.5) = 7.8 +/- 0.4 mmol L(-1)), magnesium (299.2 +/- 14.1 nmol Pi min(-1) mg(-1), K(0.5) = 767.3 +/- 36.1 mmol L(-1)), potassium (300.6 +/- 153 nmol Pi min(-1) mg(-1), K(0.5) = 1.6 +/- 0.08 mmol L(-1)) and ammonium (V = 345.1 +/- 19.0 nmol Pi min(-1) mg(-1), K(0.5) = 6.0 +/- 0.3 mmol L(-1)) ions showed site-site interactions. Ouabain inhibited (Na(+),K(+))-ATPase activity with K(1) = 45.1 +/- 2.5 mu mol L(-1), although affinity for the inhibitor increased (K(1) = 22.7 +/- 1.1 mu mol L(-1)) in 50 mmol L(-1) NH(4)(+). Inhibition assays using ouabain plus oligomycin or ethacrynic acid suggest mitochondrial F(0)F(1)- and K(+)-ATPase activities, respectively. Ammonium and potassium ions synergistically stimulated specific activity up to 72%, inferring that these ions bind to different sites on the enzyme molecule, each modulating stimulation by the other. (C) 2009 Elsevier Inc. All rights reserved.

The influence of oscillations on global existence for a class of semi-linear wave equations

The goal of this paper is to study the global existence of small data solutions to the Cauchy problem for the nonlinear wave equation u(tt) - a(t)(2) Delta u = u(t)(2) - a(t)(2)vertical bar del u vertical bar(2). In particular we are interested in statements for the 1D case. We will explain how the interplay between the increasing and oscillating behavior of the coefficient will influence global existence of small data solutions. Copyright c 2011 John Wiley & Sons, Ltd.

Structural and Biochemical Correlates of Na(+), K(+)-ATPase Driven Ion Uptake Across the Posterior Gill Epithelium of the True Freshwater Crab, Dilocarcinus pagei (Brachyura, Trichodactylidae)

To better comprehend the structural and biochemical underpinnings of ion uptake across the gills of true freshwater crabs, we performed an ultrastructural, ultracytochemical and morphometric investigation, and kinetically characterized the Na(+), K(+)-ATPase, in posterior gill lamellae of Dilocarcinus pagei. Ultrastructurally, the lamellar epithelia are markedly asymmetrical: the thick, mushroom-shaped, proximal ionocytes contain elongate mitochondria (41% cell volume) associated with numerous (approximate to 14 mu m(2) membrane per mu m(3) cytoplasm), deep invaginations that house the Na(+), K(+)-ATPase, revealed ultracytochemically. Their apical surface is amplified (7.5 mu m(2) mu m(-2)) by stubby evaginations whose bases adjoin mitochondria below the subcuticular space. The apical membrane of the thin, distal ionocytes shows few evaginations (1.6 mu m(2) mu m(-2)), each surrounding a mitochondrion, abundant in the cytoplasm below the subcuticular space; basolateral invaginations and mitochondria are few. Fine basal cytoplasmic bridges project across the hemolymph space, penetrating into the thick ionocytes, suggesting ion movement between the epithelia. Microsomal Na(+), K(+)-ATPase specific activity resembles marine crabs but is approximate to 5-fold less than in species from fluctuating salinities, and freshwater shrimps, suggesting ion loss compensation by strategies other than Na(+) uptake. Enzyme apparent K(+) affinity attains 14-fold that of marine crabs, emphasizing the relevance of elevated K(+) affinity to the conquest of fresh water. Western blotting and biphasic ouabain inhibition disclose two alpha-subunit isoforms comprising distinct functional isoenzymes. While enzyme activity is not synergistically stimulated by NH(4)(+) and K(+), each increases affinity for the other, possibly assuring appropriate intracellular K(+) concentrations. These findings reveal specific structural and biochemical adaptations that may have allowed the establishment of the Brachyura in fresh water. J. Exp. Zool. 313A:508-523, 2010. (C) 2010 Wiley-Liss, Inc.

Assessment of the differential linear coherent scattering coefficient of biological samples

New differential linear coherent scattering coefficient, mu(CS), data for four biological tissue types (fat pork, tendon chicken, adipose and fibroglandular human breast tissues) covering a large momentum transfer interval (0.07 <= q <= 70.5 nm(-1)), resulted from combining WAXS and SAXS data, are presented in order to emphasize the need to update the default data-base by including the molecular interference and the large-scale arrangements effect. The results showed that the differential linear coherent scattering coefficient demonstrates influence of the large-scale arrangement, mainly due to collagen fibrils for tendon chicken and fibroglandular breast samples, and triacylglycerides for fat pork and adipose breast samples at low momentum transfer region. While, at high momentum transfer, the mu(CS) reflects effects of molecular interference related to water for tendon chicken and fibroglandular samples and, fatty acids for fat pork and adipose samples. (C) 2009 Elsevier B.V. All rights reserved.

Mapping changes in coastline geomorphic features using Landsat TM and ETM+ imagery: examples in southeastern Brazil

Multitemporal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) imagery was used to assess coastline morphological changes in southeastern Brazil. A spectral linear mixing approach (SLMA) was used to estimate fraction imagery representing amounts of vegetation, clean water (a proxy for shade) and soil. Fraction abundances were related to erosive and depositional features. Shoreline, sandy banks (including emerged and submerged banks) and sand spits were highlighted mainly by clean water and soil fraction imagery. To evaluate changes in the coastline geomorphic features, the fraction imagery generated for each data set was classified in a contextual approach using a segmentation technique and ISOSEG, an unsupervised classification. Evaluation of the classifications was performed visually and by an error matrix relating ground-truth data to classification results. Comparison of the classification results revealed an intense transformation in the coastline, and that erosive and depositional features are extremely dynamic and subject to change in short periods of time.

Oculometric parameters of hyperopia in children with esotropic amblyopia

Purpose: To study the oculometric parameters of hyperopia in children with esotropic amblyopia, comparing amblyopic eyes with fellow eyes. Methods: Thirty-seven patients (5-8 years old) with bilateral hyperopia and esotropic amblyopia underwent a comprehensive ophthalmic examination, including cycloplegic refraction, keratometry and A-scan ultrasonography. Anterior chamber depth, lens thickness, vitreous chamber depth and total axial length were recorded. The refractive power of the crystalline lens was calculated using Bennett`s equations. Paired Student`s t-tests were used to compare ocular biometric measurements between amblyopic eyes and their fellow eyes. The associations of biometric parameters with refractive errors were assessed using Pearson correlation coefficients and linear regression. Multivariable models including axial length, corneal power and lens power were also constructed. Results: Amblyopic eyes were found to have significantly more hyperopic refraction, less corneal power, greater lens power, shorter vitreous chamber depth and shorter axial length, despite similar anterior chamber depth and lens thickness. The strongest correlation with refractive error was observed for the axial length/corneal radius ratio (r(36) = -0.92, p < 0.001 for amblyopic and r(36) = 0.87, p < 0.001 for fellow eyes). Axial length accounted for 39.2% (R(2)) of the refractive error variance in amblyopic eyes and 35.5% in fellow eyes. Adding corneal power to the model increased R(2) to 85.7% and 79.6%, respectively. A statistically significant correlation was found between axial length and corneal power, indicating decreasing corneal power with increasing axial length, and they were similar for amblyopic eyes (r(36) = 0.53,p < 0.001) and fellow eyes (r(36) = -0.57, p < 0.001). A statistically significant correlation was also found between axial length and lens power, indicating decreasing lens power with increasing axial length (r(36) = -0.72, p < 0.001 for amblyopic eyes and r(36) = -0.69, p < 0.001 for fellow eyes). Conclusions: We observed that the correlation among the major oculometric parameters and their individual contribution to hyperopia in esotropic children were similar in amblyopic and non-amblyopic eyes. This finding suggests that the counterbalancing effect of greater corneal and lens power associated with shorter axial length is similar in both eyes of patients with esotropic amblyopia.

K/DOQI-recommended intact PTH levels do not prevent low-turnover bone disease in hemodialysis patients

The guidelines proposed by the Kidney Disease Outcomes Quality Initiative (K/DOQI) suggested that intact parathyroid hormone (iPTH) should be maintained in a target range between 150 and 300 pg ml(-1) for patients with stage 5 chronic kidney disease. Our study sought to verify the effectiveness of that range in preventing bone remodeling problems in hemodialysis patients. We measured serum ionized calcium and phosphorus while iPTH was measured by a second-generation assay. Transiliac bone biopsies were performed at the onset of the study and after completing 1 year follow-up. The PTH levels decreased within the target range in about one-fourth of the patients at baseline and at the end of the study. The bone biopsies of two-thirds of the patients were classified as showing low turnover and a one-fourth showed high turnover, the remainder having normal turnover. In the group achieving the target levels of iPTH 88% had low turnover. Intact PTH levels less than 150 pg ml(-1) for identifying low turnover and greater than 300 pg ml(-1) for high turnover presented a positive predictive value of 83 and 62%, respectively. Our study suggests that the iPTH target recommended by the K/DOQI guidelines was associated with a high incidence of low-turnover bone disease, suggesting that other biochemical markers may be required to accurately measure bone-remodeling status in hemodialysis patients.

Age-related gray matter volume changes in the brain during non-elderly adulthood

Previous magnetic resonance imaging (MRI) studies described consistent age-related gray matter (GM) reductions in the fronto-parietal neocortex, insula and cerebellum in elderly subjects, but not as frequently in limbic/paralimbic structures. However, it is unclear whether such features are already present during earlier stages of adulthood, and if age-related GM changes may follow non-linear patterns at such age range. This voxel-based morphometry study investigated the relationship between GM volumes and age specifically during non-elderly life (18-50 years) in 89 healthy individuals (48 males and 41 females). Voxelwise analyses showed significant (p < 0.05, corrected) negative correlations in the right prefrontal cortex and left cerebellum, and positive correlations (indicating lack of GM loss) in the medial temporal region, cingulate gyrus, insula and temporal neocortex. Analyses using ROI masks showed that age-related dorsolateral prefrontal volume decrements followed non-linear patterns, and were less prominent in females compared to males at this age range. These findings further support for the notion of a heterogeneous and asynchronous pattern of age-related brain morphometric changes, with region-specific non-linear features. (C) 2009 Elsevier Inc. All rights reserved.

Characterization of the Biocompatible Magnetic Colloid on the Basis of Fe(3)O(4) Nanoparticles Coated with Dextran, Used as Contrast Agent in Magnetic Resonance Imaging

The magnetic resonance imaging contrast agent, the so-called Endorem (TM) colloidal suspension on the basis of superparamagnetic iron oxide nanoparticles (mean diameter of 5.5 nm) coated with dextran, were characterized on the basis of several measurement techniques to determine the parameters of their most important physical and chemical properties. It is assumed that each nanoparticle is consisted of Fe(3)O(4) monodomain and it was observed that its oxidation to gamma-Fe(2)O(3) occurs at 253.1 degrees C. The Mossbauer spectroscopy have shown a superparamagnetic behavior of the magnetic nanoparticles. The Magnetic Resonance results show an increase of the relaxation times T(1), T(2), and T(2)* with decreasing concentration of iron oxide nanoparticles. The relaxation effects of SPIONs contrast agents are influenced by their local concentration as well as the applied field strength and the environment in which these agents interact with surrounding protons. The proton relaxation rates presented a linear behavior with concentration. The measured values of thermooptic coefficient partial derivative n/partial derivative T, thermal conductivity K, optical birefringence Delta n(0), nonlinear refractive index n(2), nonlinear absorption beta` and third-order nonlinear susceptibility vertical bar chi((3))vertical bar are also reported.

Linear IgA dermatosis induced by pregnancy

Linear IgA disease is a rare autoimmune subepidermal bullous disorder characterized by linear IgA deposits at the epidermal basement membrane zone. According to the literature, in patients who have linear IgA disease and become pregnant, the disease tends to improve. We report a case of linear IgA disease induced by pregnancy, successfully treated with dapsone and prednisone with no adverse effects observed in the patient and her newborns.

Leptospirosis pulmonary haemorrhage syndrome is associated with linear deposition of immunoglobulin and complement on the alveolar surface

Leptospirosis is a zoonotic infection associated with severe diseases such as leptospirosis pulmonary haemorrhage syndrome (LPHS). The cause of pulmonary haemorrhage is unclear. Understanding which mechanisms and processes are involved in LPHS will be important in treatment regimens under development for this life-threatening syndrome. In the present study, we evaluated 30 lung specimens from LPHS patients and seven controls using histology and immunohistochemistry (detection of IgM, IgG, IgA and C3) in order to describe the pathological features associated with this syndrome. Immunoglobulin deposits were detected on the alveolar surface in 18/30 LPHS patients. Three staining patterns were observed for the immunoglobulins and C3 in the lung tissues of LPHS patients: AS, delicate linear staining adjacent to the alveolar surface, which was indicative of a membrane covering the luminal surface of type I and II pneumocyte cells; S, heterogeneous staining which was sporadically distributed along the alveolar septum; and IA, weak, focal intra-alveolar granular staining. Human LPHS is associated with individual and unique histological patterns that differ from those of other causes of pulmonary haemorrhage. In the present study, it was found that the linear deposition of immunoglobulins (IgA, IgG and IgM) and complement on the alveolar surface may play a role in the pathogenesis of pulmonary haemorrhage in human leptospirosis.

Metallic Voice: Physiological and Acoustic Features

The metallic voice is usually confused with ring or nasality by singers and nontrained listeners. who are not used to perceptual vocal analysis. They believe a metallic voice results from a rise in fundamental frequency. A diagnostic error in this aspect may lead to lowering pitch, an incorrect procedure that Could Cause vocal overload and fatigue. The purpose of this article is to Study the quality of metallic voice considering the correlation between information of the physiological and acoustic plans, based on a perceptive consensual assumption. Fiberscopic video pharyngolaryngoscopy was performed on 21 professional singers while speaking vowel [e]-in normal and metallic modes to observe muscular movements and structural changes of the velopharynx, pharynx, and larynx. Vocal samples captured simultaneously to the fiberscopic examination were acoustically analyzed. Frequency and amplitude of the first four formants (F(1), F(2), F(3), and F(4)) were extracted by means of linear predictor coefficients (LPC) Spectrum and were statistically analyzed. Vocal tract adjustments such as velar lowering, pharyngeal wall narrowing, laryngeal rise, aryepiglottic, and lateral laryngeal constrictions were frequently found: there were no significant changes in frequency and amplitude of F(1) in the metallic voiced there were significant increases in amplitudes of F(2), F(3), and F(4) and in frequency for F, metallic Voice perceived as louder was correlated to an increase ill amplitude of F(3) and F(4). Physiological adjustments of velopharynx, pharynx, and larynx are combined in characterizing the metallic voice and can be acoustically related to changes in formant pattern.

ADHD in a representative sample of the Brazilian population: estimated prevalence and comparative adequacy of criteria between adolescents and adults according to the item response theory

Background: Attention deficit hyperactivity disorder (ADHD) is a clinically significant disorder in adulthood, but current diagnostic criteria and instruments do not seem to adequately capture the complexity of the disorder in this developmental phase. Accordingly, there are limited data on the proportion of adults affected by the disorder, specially in developing countries. Method: We assessed a representative household sample of the Brazilian population for ADHD with the Adult ADHD Self-report Scale (ASRS) Screener, and evaluated the instrument according to the Rasch model of item response theory. Results: The sample was comprised by 3007 individuals, and the overal prevalence of positive screeners for ADHD was 5.8% [95% confidence interval (CI), 4.8-7.0]. Rasch analyses revealed the misfitt of the overall sample to expectations of the model. The evaluation of the sample stratified by age revealed that data for adolescents showed a signficant fittnes to the model expectations, while items completed by adults were not adequated. Conclusions: The lack of fitness to the model for adult respondents challenges the possibility of a linear transformation of the ordinal data into interval measures and the utilization of parametric analyses of data. This result suggests that diagnostic criteria and instruments for adult ADHD must take into account a developmental perspective. Moreover, it calls for further evaluation of currently employed research methods in light of modern theories of psychometrics. Copyright (C) 2010 John Wiley & Sons, Ltd.

VKORC1 polymorphisms in Brazilians: comparison with the Portuguese and Portuguese-speaking Africans and pharmacogenetic implications

Aims: The heterogeneity of the Brazilian population renders the extrapolation of pharmacogenomic data derived from well-defined ethnic groups inappropriate. We investigated the influence of self-reported `race/color`, geographical origin and genetic ancestry on the distribution of four VKORC1 SNPs and haplotypes in Brazilians. Comparative data were obtained from two major ancestral roots of Brazilians: Portuguese and Africans from former Portuguese colonies. Materials & methods: A total of 1037 healthy adults Brazilians, recruited at four different geographical regions and self identified as white, brown or black (race/color categories), 89 Portuguese and 216 Africans from Angola and Mozambique were genotyped for the VKORC1 3673G>A (rs9923231), 5808T>G (rs2884737), 6853G>C (rs8050894) and 9041G>A (rs7294) polymorphisms using TaqMan (R) (Applied Biosystems, CA, USA) assays. VKORC1 haplotypes were statistically inferred using the haplo.stats software. We inferred the statistical association between the distribution of the VKORC1 polymorphisms among Brazilians and self-reported color, geographical region and genetic ancestry by fitting multinomial log linear models via neural networks. Individual proportions of European and African ancestry were used to assess the impact of genetic admixture on the frequency distribution of VKORC1 polymorphisms among Brazilians, and for the comparison of Brazilians with Portuguese and Africans. Results: The frequency distribution of the 3673G>A and 5808T>G polymorphisms, and VKORC1 haplotypes among Brazilians varies across geographical regions, within self-reported color categories and according to the individual proportions of European and African genetic ancestry. Notably, the frequency of the warfarin sensitive VKORC1 3673A allele and the distribution of VKORC1 haplotypes varied continuously as the individual proportion of European ancestry increased in the entire cohort, independently of race/color categorization and geographical origin. Brazilians with more than 80% African ancestry differ significantly from Angolans and Mozambicans in frequency of the 3673G>A, 5808T>G and 6853G>C polymorphisms and haplotype distribution, whereas no such differences are observed between Brazilians with more than 90% European ancestry and Portuguese individuals. Conclusion: The diversity of the Brazilian population, evident in the distribution of VKORC1 polymorphisms, must be taken into account in the design of pharmacogenetic clinical trials and dealt with as a continuous variable. Warfarin dosing algorithms that include `race` terms defined for other populations are clearly not applicable to the heterogeneous and extensively admixed Brazilian population.