Tributyltin (TBT) toxicity: Effects on enteric neuronal plasticity and intestinal barrier of rats' duodenum.

Tributyltin (TBT) is a biocide used in the formulation of antifouling paints and it is highly harmful. Despite the ban, the compound persists in the environment, contaminating marine foodstuffs and household products. Therefore, considering the route of exposure to the contaminant, the gastrointestinal tract (GIT) acts as an important barrier against harmful substances and is a potential biomarker for understanding the consequences of these agents. This work aimed to evaluate histological and neuronal alterations in the duodenum of male Wistar rats that received 20 ng/g TBT and 600 ng/g via gavage for 30 consecutive days. After the experimental period, the animals were euthanized, and the duodenum was intended for neuronal histochemistry (total and metabolically active populations) and histological routine (morphometry and histopathology). The results showed more severe changes in neuronal density and intestinal morphometry in rats exposed to 20 ng/g, such as total neuronal density decrease and reduction of intestinal layers. In rats exposed to 600 ng/g of TBT, it was possible to observe only an increase in intraepithelial lymphocytes. We conclude that TBT can be more harmful to intestinal homeostasis when consumed in lower concentrations.

Forage sources in total mixed rations early in life influences performance, metabolites, and behaviour of dairy calves.

The objective of this study was to evaluate effects of forage inclusion and sources on performance, metabolism, and feeding behavior of dairy calves. Forty-eight Holstein calves were blocked and randomly assigned to 1 of 4 dietary treatments according to sex, and body weight (BW) at 28 d of life to determine the effects of feeding forage sources (ensiled and dry), with different quality on performance, metabolites, and behavior. Treatments consisted of a no-forage coarsely ground starter (CON); or total mixed ration containing 7.5% on DM basis of Tifton hay of either medium quality (MH) or low quality (LH); or 10% on DM basis of corn silage (CS). During the first 28 d of life, all calves received 3 L of whole milk twice daily, a commercial pelleted starter and no forage, and water ad libitum. After that, the solid diet was changed to the respective dietary treatments. Calves were gradually weaned from 52 to 56 d of age, and followed for 14 d post-weaning. Individual solid feed and milk intakes were recorded daily, and BW and metabolic indicators of intermediate metabolism were recorded weekly. Behavior was recorded, and the analysis was conducted on wk 7 (preweaning) and 10 (post-weaning). Solid feed intake increased at wk 7 and 8 when MH, LH, and CS were included in TMR; the same results were observed post-weaning. The diets did not affect the average daily gain and body weight, but the feed efficiency increased with the CON diet. The ß-hydroxybutyrate concentration was greater in calves receiving TMR containing forage than CON diet. Furthermore, calves supplemented with forage had a greater rumination time. In conclusion, all forage sources included in the TMR showed feed intake and behavior benefits, reinforcing the need for fiber from forage in pre- and post-weaning diets.

Impact of Treatment on Host Responses in Young Individuals with Periodontitis.

Grade C periodontitis in young individuals is characterized by severe/rapid periodontal destruction, usually early onset, in systemically healthy individuals. An individual's host response, triggered by a dysbiotic subgingival biofilm, has been reported as a contributor to the tissue destruction, although mechanisms of this response and contributions to such disease remain poorly understood. Nonsurgical treatment has resulted in positive clinical responses for both localized (now molar-incisor pattern) and generalized forms of grade C periodontitis, especially when adjunctive systemic antibiotics are used. Nonsurgical treatment may also affect host responses, although mechanisms leading to significant changes in this response remain unclear. Significant effects on inflammatory response to antigens/bacteria have been described posttreatment, but evidence for long-term effects remains limited. Nonsurgical treatment in these individuals may also modulate a variety of host markers in serum/plasma and gingival crevicular fluid along with clinical parameter improvements. The impact of other adjuncts to nonsurgical treatment focusing on controlling exacerbated immunoinflammatory responses needs to be further explored in grade C periodontitis in young individuals. Recent evidence suggests that nonsurgical treatment with adjunctive laser therapy may modulate host and microbial responses in those subjects, at least in the short term. Available evidence, while very heterogeneous (including variations in disease definition and study designs), does not provide clear conclusions on this topic yet provides important insights for future studies. In this review, studies within the past decade evaluating the impact of nonsurgical treatment on systemic/local host responses in young individuals with grade C periodontitis, as well as long-term clinical responses posttreatment, will be critically appraised and discussed.

Effect of the intra-alveolar administration of dexamethasone on swelling, trismus, and pain after impacted lower third molar extraction: a randomized, double-blind clinical trial.

BACKGROUND: To evaluate the efficacy of intra-alveolar administration of dexamethasone 4 mg in the control of edema, trismus, and pain resulting from the extraction of impacted lower third molars and the drug permeability through the oral mucosa by in silico prediction. MATERIAL AND METHODS: The randomized, double-blind, split-mouth clinical trial included patients who had both impacted lower third molars in equivalent positions. Hemiarches were divided into control side when dexamethasone was administered orally and experimental side when dexamethasone was administered using the intra-alveolar route. Patients were evaluated considering edema, trismus, and pain. The permeability of dexamethasone through the oral mucosa was assessed by in silico prediction. Student's t-test was selected for comparative analysis of edema and trismus, and the chi-square test analyzed the distribution of postoperative pain between the sides. RESULTS: There were no significant differences between the routes of administration in measuring symptoms between the pre and postoperative times (p>0.05). In silico prediction suggested that dexamethasone molecular characteristics facilitate intra-alveolar administration. CONCLUSIONS: Intra-alveolar administration had similar efficacy to oral administration in controlling symptoms of post-surgical inflammation of impacted lower third molars.

Involvement of monoaminergic targets in the antidepressant- and anxiolytic-like effects of the synthetic alkamide riparin IV: Elucidation of further mechanisms through pharmacological, neurochemistry and computational approaches.

Despite recent advances, current antidepressants have considerable limitations: late onset of action and the high profile of refractoriness. Biomedical research with natural products has gained growing interest in the last years, and had provide useful candidates for new antidepressants. Riparins are a group of natural alkamides obtained from Aniba riparia, which had marked neuroactive effects, mainly as antidepressant and antinociceptive agents. We made modifications of the basic structure of riparins, originating a synthetic alkamide, also known as riparin IV (RipIV). RipIV demonstrated a superior analgesic effect than its congeners and a marked antidepressant-like effect. However, the basic mechanism for the central effects of RipIV remains unknown. Here, we aimed to investigate the participation of monoaminergic neurotransmission targets in the antidepressant-like effects of RipIV. To do this, we applied a combined approach of experimental (classical pharmacology and neurochemistry) and computer-aided techniques. Our results demonstrated that RipIV presented antidepressant- and anxiolytic-like effects without modifying locomotion and motor coordination of mice. Also, RipIV increased brain monoamines and their metabolite levels. At the higher dose (100 mg/kg), RipIV increased serotonin concentrations in all studied brain areas, while at the lower one (50 mg/kg), it increased mainly dopamine and noradrenaline levels. When tested with selective receptor antagonists, RipIV antidepressant effect showed dependence of the activation of multiple targets, including D1 and D2 dopamine receptors, 5-HT2A/2, 5-HT3 receptors and α2 adrenergic receptors. Molecular docking demonstrated favorable binding conformation and affinity of RipIV to monoamine oxidase B (MAO-B), serotonin transporter (SERT), α1 receptor, D2 receptor, dopamine transporter (DAT) and at some extent GABA-A receptor. RipIV also presented a computationally predicted favorable pharmacokinetic profile. Therefore, this study demonstrated the involvement of monoaminergic targets in the mechanism of RipIV antidepressant-like action, and provide evidence of it as a promising new antidepressant.

Bacteriophage amplification assay for detection of Listeria spp. using virucidal laser treatment

A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO) were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring a total reduction in titer phage (ca. 10(8) pfu/mL) without affecting the viability of L. monocytogenes cells. Artificially inoculated skimmed milk revealed mean populations of the bacteria as low as between 13 cfu/mL (1.11 log cfu/mL), after a 10-h assay duration. Virucidal laser treatment demonstrated better protection of Listeria cells than the other agents previously tested. The protocol was faster and easier to perform than standard procedures. This protocol constitutes an alternative for rapid, sensitive and quantitative detection of L. monocytogenes.

Bacteriophage amplification assay for detection of Listeria spp. using virucidal laser treatment.

A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO) were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring a total reduction in titer phage (ca. 10(8) pfu/mL) without affecting the viability of L. monocytogenes cells. Artificially inoculated skimmed milk revealed mean populations of the bacteria as low as between 13 cfu/mL (1.11 log cfu/mL), after a 10-h assay duration. Virucidal laser treatment demonstrated better protection of Listeria cells than the other agents previously tested. The protocol was faster and easier to perform than standard procedures. This protocol constitutes an alternative for rapid, sensitive and quantitative detection of L. monocytogenes.

Efeito da Lecitina de Soja sobre os Lipídeos e Proteína C reativa e na prevenção da Hipertrofia Ventricular Esquerda de Camundongos Hiperlipidêmicos / Effect of soy lecithin on lipids and C-reactive protein and the prevention of Left Ventricular Hypertrophy in hyperlipidemic mice

A regulação do metabolismo lipídico com drogas ou alimentos naturais é um alvo importante para diminuir o risco de doenças cardiovasculares. O objetivo deste estudo foi verificar o efeito da lecitina de soja na dislipidemia e na hipertrofia ventricular de camundongos hipercolesterolêmicos. Utilizaram-se quatro grupos de camundongos LDLr-/- com 3 meses de idade que receberam a seguintes dietas: Grupo S- ração padrão; Grupo S+Lec- ração padrão e lecitina de soja; Grupo HL- ração hiperlipídica; e Grupo HL+Lec- ração hiperlipídica e lecitina de soja. Após 15 dias, o sangue foi coletado para análise sérica dos lipídeos e da proteína C reativa. O ventrículo esquerdo foi separado, a proporção peso ventricular (mg) pelo peso do animal (g) foi calculada e, em seguida, processado histologicamente. Cortes histológicos foram corados com hematoxilina/eosina e picrosírius red para avaliar alterações morfológicas e morfométricas ventriculares. A lecitina de soja apresentou efeito antidislipidêmico e aumentou os níveis séricos de HDL nos camundongos do grupo S+Lec. Entretanto, nos camundongos do grupo HL+lec, a lecitina de soja não preveniu a dislipidemia, apenas aumentou o nível sérico do HDL. Este efeito nestes animais influenciou no processo inflamatório cardiovascular, reduzindo o nível sérico de proteína C reativa; e prevenindo a hipertrofia ventricular esquerda. A utilização da lecitina de soja representa um tratamento e/ou uma prevenção alternativa de baixo custo para as dislipidemias não associadas com dieta hiperlipídica. Contudo, a lecitina de soja aumenta os níveis séricos do HDL prevenindo o desenvolvimento da HVE mesmo em dislipidemias associadas com dieta hiperlipídica.

The regulation of lipid metabolism with drugs or natural foods is an important target for reducing the risk of cardiovascular disease. The aim of this study was to investigate the effects of soy lecithin on left ventricular hypertrophy (LVH) and dyslipidemia in hypercholesterolemic mice. We used four experimental groups of LDLr-/- mice (aged 3 months), which received the following diets: Group S: standard diet, Group S+Lec: standard diet and soy lecithin; Group HL: hyperlipidic diet and Group HL+Lec: hyperlipidic diet and soy lecithin. After 15 days on these diets, blood was collected for analysis of serum lipids and C-reactive protein. The left ventricle was dissected out and weighed and the ratio of its weight to the body weight of the animal was calculated, after which it was processed histologically. Sections were stained with hematoxylin-eosin and picrosirius red, to assess morphological and morphometric changes in the ventricle. In Group S+Lec, the soy lecithin had an antidyslipidemic effect and enhanced the serum levels of HDL. However, in the mice in group HL+Lec, soy lecithin did not prevent dyslipidemia, only increasing the serum level of HDL. These effects in these animals influenced the cardiovascular inflammatory process, reducing the level of serum C-reactive protein and preventing LVH. Soy lecithin could thus be used as a treatment or a low-cost alternative preventative measure against dyslipidemia associated with a non-fat diet. However, soy lecithin increases the serum level of HDL, reducing the risk of LVH even in dyslipidemia associated with a high-fat diet.

Virulence characteristics of genetically related isolates of group B streptococci from bovines and humans.

The present study had the objective of evaluating the pathogenic potential of the genetically related strains of Streptococcus agalactiae no. 80427 (human origin) and no. 87159 (bovine origin), and comparing the results with two other strains isolated from bovine mastitis (no. 87244) and invasive human infection (no. 90356), with no genetic or epidemiologic relationship between them or with the first 2 isolates. Virulence genes hylB (hyaluronidase) and lmb (laminin-binding protein) were detected in the 4 strains, and genes bac (beta protein) and bca (alpha protein) were only detected in human strains. The protein profile obtained using SDS-PAGE did not indicate any differences between the 4 strains. No significant difference was detected between human and bovine strains in the assays of adherence to and invasion of 16HBe cells, as well as in the resistance assay for intracellular bacterial survival in macrophages. However, the strain 87159 exhibited a greater survival in the killing test with whole human blood and was more virulent in newborn mice than the 80427 strain. The strain 87244 was not virulent in mice. These data suggest that isolates of human and bovine origins may express similar virulence attributes, leading to a possible, however limited, dissemination.

Genotyping of Streptococcus agalactiae strains isolated from fish, human and cattle and their virulence potential in Nile tilapia.

Streptococcus agalactiae (Lancefield group B; GBS) is a pathogen that causes meningoencephalitis in fish, mastitis in cows, and neonatal sepsis in humans. The objective of this study was to characterize S. agalactiae isolated from fish (n=27), cows (n=9), and humans (n=10) using pulsed-field gel electrophoresis (PFGE) and to investigate the virulence of the identified strains in Nile tilapia (Oreochromis niloticus). The PFGE types were determined by dendogram analyses and the in vivo virulence was evaluated by experimental infection (using i.p. and immersion routes) of Nile tilapia. Among the fish strains, 5 different PFGE patterns were observed and 21 strains showed the same genetic pattern. In some farms two or three profiles occurred simultaneously. The bovine and human strains exhibited high genetic diversity and few relationships were established among S. agalactiae strains from the three host origins analyzed. Eight S. agalactiae strains from fish caused high mortality of Nile tilapia. Three bovine strains infected Nile tilapia (by i.p. route) and two of those strains caused clinical signs of meningoencephalitis. All human strains (n=5) infected Nile tilapia (by i.p. route) and meningoencephalitis was induced by one strain (by both i.p. and immersion routes). In conclusion, the analyzed strains from the three natural hosts did not show genetic relatedness, yet some of the bovine and human strains were able to infect fish and cause meningoencephalitis. We suggest that genetic linkage is not a prerequisite for S. agalactiae to cross the host-specific barrier.

Genetic relatedness between group B streptococci originating from bovine mastitis and a human group B Streptococcus type V cluster displaying an identical pulsed-field gel electrophoresis pattern.

Twenty isolates of group B streptococcus (GBS) were recovered from the milk of cows with bovine mastitis on three farms located in the south and south-east of Brazil between 1987 and 1988. These isolates were characterised by molecular methods and compared with a collection of 103 human GBS isolates from colonised and infected patients in the same region between 1980 and 2003. Some of the bovine isolates shared identical or similar pulsed-field gel electrophoresis (PFGE) patterns with a PFGE clone of human GBS type V. In addition, these bovine and human isolates also possessed the same ribotype. Multilocus sequence typing (MLST) of representative isolates confirmed the genetic relationship between the human and bovine GBS isolates with identical PFGE patterns, which clustered in the same ST-26 clonal complex. These data support the hypothesis that some bovine GBS strains are related closely to human isolates and may infect humans, or vice versa. Further comparative genomic analyses of GBS isolates from bovine and human origins are required to investigate this hypothesis further.

Pulsed-field gel electrophoresis of human group B streptococci isolated in Brazil.

The present study addresses epidemiological aspects of Brazilian human group B streptococci (GBS). GBS (103 isolates) were serotyped with specific rabbit anticapsular antibodies by double diffusion in agarose gels. They represented 3 serotypes: 26 II, 41 III, and 36 V. Thereafter, the strains were characterized by pulsed-field gel electrophoresis (PFGE) of DNA treated with SmaI. DNA restriction band sizes were compared and displayed 54 PFGE profiles that were arranged into 18 patterns. Of the predominant patterns detected for the 41 type III isolates 4 were observed in 15 strains from individuals with infections whereas only 3 were identified in 22 streptococci from healthy carriers. Such differences did not separate types II and V streptococci from carriers and patients. The PFGE method is a sensitive, precise, and powerful tool for discriminating streptococcal strains for epidemiological purposes.

Grid requirements for the integration of biomedical information resources for health applications.

OBJECTIVES: The goal of this paper is to identify how Grid technology can be applied for the development and deployment of integration systems, bringing together distributed and heterogeneous biomedical information sources for medical applications. METHODS: The integration of new genetic and medical knowledge in clinical workflows requires the development of new paradigms for information management in which the ability to access and relate disparate data sources is essential. We adopt a requirements perspective based on the user needs we have identified in the development of the INFOGENMED system to assess current Grid technology against those requirements. RESULTS: The gap between Grid features and distributed biomedical information integration needs is characterized. Results from prospective studies are also reported. CONCLUSIONS: Grid infrastructures offer advanced features for the deployment of collaborative computational environments across virtual organizations. New Grid developments are in line with the problem of multiple site information integration. From the INFOGENMED point of view, Grid infrastructures need to evolve to implement structured data access services and semantic content description and discovery.

Freqüência de anemia infecciosa em eqüinos no Acre, 1986 a 1996 / Frequency of equine infectious anemia in the State of Acre, Brazil, from 1986 to 1996

Foram analisadas as fichas de 9.963 eqüídeos do Acre, submetidos ao teste de imunodifusäo em gel de ágar (IDGA) para anemia infecciosa eqüina (AIE), no período de 1986 a 1996. As regiöes sócio-ecológicas da Bacia do Alto Juruá, Alto Acre e Alta Bacia do Purus apresentaram os maiores índices da doença, o que caracteriza a associaçäo entre regiäo e positividade. Essas áreas säo fronteiriças com o Peru, Bolívia e o Estado do Amazonas, säo distantes de Rio Branco, capital do Estado, onde muitas vezes é difícil o acesso pelas estradas, revelando serem áreas de risco. As regiöes Oriental e Rio Branco apresentaram baixos índices de positividade. Näo se observou diferença estatística entre animais positivos e negativos quanto à espécie, sexo, raça e idade

Metabolite and light regulation of metabolism in plants: lessons from the study of a single biochemical pathway

We are using molecular, biochemical, and genetic approaches to study the structural and regulatory genes controlling the assimilation of inorganic nitrogen into the amino acids glutamine, glutamate, aspartate and asparagine. These amino acids serve as the principal nitrogen-transport amino acids in most crop and higher plants including Arabidopsis thaliana. We have begun to investigate the regulatory mechanisms controlling nitrogen assimilation into these amino acids in plants using molecular and genetic approaches in Arabidopsis. The synthesis of the amide amino acids glutamine and asparagine is subject to tight regulation in response to environmental factors such as light and to metabolic factors such as sucrose and amino acids. For instance, light induces the expression of glutamine synthetase (GLN2) and represses expression of asparagine synthetase (ASN1) genes. This reciprocal regulation of GLN2 and ASN1 genes by light is reflected at the level of transcription and at the level of glutamine and asparagine biosynthesis. Moreover, we have shown that the regulation of these genes is also reciprocally controlled by both organic nitrogen and carbon metabolites. We have recently used a reverse genetic approach to study putative components of such metabolic sensing mechanisms in plants that may be conserved in evolution. These components include an Arabidopsis homolog for a glutamate receptor gene originally found in animal systems and a plant PII gene, which is a homolog of a component of the bacterial Ntr system. Based on our observations on the biology of both structural and regulatory genes of the nitrogen assimilatory pathway, we have developed a model for metabolic control of the genes involved in the nitrogen assimilatory pathway in plants

Metabolite and light regulation of metabolism in plants: lessons from the study of a single biochemical pathway.

We are using molecular, biochemical, and genetic approaches to study the structural and regulatory genes controlling the assimilation of inorganic nitrogen into the amino acids glutamine, glutamate, aspartate and asparagine. These amino acids serve as the principal nitrogen-transport amino acids in most crop and higher plants including Arabidopsis thaliana. We have begun to investigate the regulatory mechanisms controlling nitrogen assimilation into these amino acids in plants using molecular and genetic approaches in Arabidopsis. The synthesis of the amide amino acids glutamine and asparagine is subject to tight regulation in response to environmental factors such as light and to metabolic factors such as sucrose and amino acids. For instance, light induces the expression of glutamine synthetase (GLN2) and represses expression of asparagine synthetase (ASN1) genes. This reciprocal regulation of GLN2 and ASN1 genes by light is reflected at the level of transcription and at the level of glutamine and asparagine biosynthesis. Moreover, we have shown that the regulation of these genes is also reciprocally controlled by both organic nitrogen and carbon metabolites. We have recently used a reverse genetic approach to study putative components of such metabolic sensing mechanisms in plants that may be conserved in evolution. These components include an Arabidopsis homolog for a glutamate receptor gene originally found in animal systems and a plant PII gene, which is a homolog of a component of the bacterial Ntr system. Based on our observations on the biology of both structural and regulatory genes of the nitrogen assimilatory pathway, we have developed a model for metabolic control of the genes involved in the nitrogen assimilatory pathway in plants.

Genomic characterization of wild-type measles viruses that circulated in different states in Brazil during the 1997 measles epidemic.

Despite the marked reduction in the incidence of measles in Brazil, a measles epidemic occurred in this country in 1997. The measles cases observed during this epidemic began to reappear in large numbers in São Paulo, and spread to Rio de Janeiro and other Brazilian states. In the present study molecular biology techniques were used for the detection and genomic characterization of measles viruses from clinical samples such as urine and nasopharyngeal secretions collected in the states of Rio de Janeiro, Minas Gerais and Paraná, during the 1997 epidemic. RT-PCR and nucleotide sequence analysis of part of the carboxyl-terminal region of the nucleoprotein gene of measles viruses obtained directly from clinical samples or from infected cell cultures during this epidemic classified all as wild-type of genotype D6. As the genotype D6 was identified in different Brazilian states, this study demonstrated that this genotype was circulating in Brazil during the 1997 epidemic.

Carbon and amino acids reciprocally modulate the expression of glutamine synthetase in Arabidopsis.

In bacteria and yeast, glutamine synthetase (GS) expression is tightly regulated by the metabolic status of the cell, both at the transcriptional and posttranscriptional levels. We discuss the relative contributions of light and metabolic cues on the regulation of members of the GS gene family (chloroplastic GS2 and cytosolic GS1) in Arabidopsis. These studies reveal that the dramatic induction of mRNA for chloroplastic GS2 by light is mediated in part by phytochrome and in part by light-induced changes in sucrose (Suc) levels. In contrast, the modest induction of mRNA for cytosolic GS1 by light is primarily mediated by changes in the levels of carbon metabolites. Suc induction of mRNA for GS2 and GS1 occurs in a time- and dose-dependent manner. Suc-induced changes in GS mRNA levels were also observed at the level of GS enzyme activity. In contrast, amino acids were shown to antagonize the Suc induction of GS, both at the level of mRNA accumulation and that of enzyme activity. For GS2, the gene whose expression was the most dramatically regulated by metabolites, we used a GS2 promoter-beta-glucuronidase fusion to demonstrate that transcriptional control is involved in this metabolic regulation. Our results suggest that the metabolic regulation of GS expression in plants is controlled by the relative abundance of carbon skeletons versus amino acids. This would allow nitrogen assimilation into glutamine to proceed (or not) according to the metabolic status and biosynthetic needs of the plant. This type of GS gene regulation is reminiscent of the nitrogen regulatory system in bacteria, and suggests an evolutionary link between metabolic sensing and signaling in bacteria and plants.