Arterial acid-base status during digestion and following vascular infusion of NaHCO3 and HCl in the South American rattlesnake, Crotalus durissus

Digestion is associated with gastric secretion that leads to an alkalinisation of the blood, termed the alkaline tide. Numerous studies on different reptiles and amphibians show that while plasma bicarbonate concentration ([HCO3-](pl)) increases substantially during digestion, arterial pH (pHa) remains virtually unchanged, due to a concurrent rise in arterial PCO2 (PaCO2) caused by a relative hypoventilation. This has led to the suggestion that postprandial amphibians and reptiles regulate pHa rather than PaCO2.Here we characterize blood gases in the South American rattlesnake (Crotalus durissus) during digestion and following systemic infusions of NaHCO3 and HCl in fasting animals to induce a metabolic alkalosis or acidosis in fasting animals. The magnitude of these acid-base disturbances were similar in magnitude to that mediated by digestion and exercise. Plasma [HCOT] increased from 18.4+/-1.5 to 23.7+/-1.0 mmol L-1 during digestion and was accompanied by a respiratory compensation where PaCO2 increased from 13.0+/-0.7 to 19.1+/-1.4 mm Hg at 24 h. As a result, pHa decreased slightly, but were significantly below fasting levels 36 h into digestion. Infusion of NaHCO3 (7 mmol kg(-1)) resulted in a 10 mmol L-1 increase in plasma [HCO3-] within 1 h and was accompanied by a rapid elevation of pHa (from 7.58+/-0.01 to 7.78+/-0.02). PaCO2, however, did not change following HCO3- infusion, which indicates a lack of respiratory compensation. Following infusion of HCl (4 mmol kg(-1)), plasma pHa decreased by 0.07 units and [HCO3-](pl) was reduced by 4.6 mmol L-1 within the first 3 h. PaCO2, however, was not affected and there was no evidence for respiratory compensation.Our data show that digesting rattlesnakes exhibit respiratory compensations to the alkaline tide, whereas artificially induced metabolic acid-base disturbances of same magnitude remain uncompensated. It seems difficult to envision that the central and peripheral chemoreceptors would experience different stimuli during these conditions. One explanation for the different ventilatory responses could be that digestion induces a more relaxed state with low responsiveness to ventilatory stimuli. (C) 2005 Elsevier B.V. All rights reserved.

In situ hybridization of bat chromosomes with human (TTAGGG)n probe, after previous digestion with Alu I

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

Evaluation of simulated external root resorptions with digital radiography and digital subtraction radiography

Introduction: Root resorption can cause damage in orthodontic patients. Digital subtraction radiography (DSR) is a useful resource for the detection of mineral losses. The purpose of this study was to compare the efficacy of digital radiography (DR) and DSR in detecting simulated external root resorption. Examiner agreement between the 2 techniques was also evaluated. Methods: Root resorptions of various sizes were simulated on the apical and lingual aspects of 49 teeth from 9 dry human mandibles. The teeth were radiographed in standardized conditions. The radiographs were registered with Regeemy Image Registration and Mosaicking (version 0.2.43-RCB, DPI-INPE, Sao Jose dos Campos, São Paulo, Brazil) and subtracted with Image Tool (University of Texas Health Science Center at San Antonio). The subtracted images and the digital radiographs were evaluated by 3 oral radiologists. Results: No statistically significant differences were found for the methods in the detection of apical root resorptions, independently from lesion size, and of lingual resorptions of 1.2 mm or greater. DSR was significantly better than DR for detection of lingual resorptions up to 1 mm. Resorptions less than 0.5 mm were not precisely detected by either method. DSR provided better intraexaminer and interexaminer agreement than did DR. Conclusions: Both methods are precise for detection of apical root resorptions as small as 0.5 mm and lingual resorptions of 1 mm or more. However, DSR frequently performed better than did DR. (Am J Orthod Dentofacial Orthop 2011;139:324-33)

Simultaneous removal of chromium and leather dye from simulated tannery effluent by photoelectrochemistry

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

Relative antioxidant activity of Brazilian medicinal plants for gastrointestinal diseases

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

Gastrointestinal helminths in calves and cows in an organic milk production system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ruminal parameters analyzed in remaining digestion residue of roughages in the in vitro/gas system

O desempenho animal é a medida mais direta de se avaliar a qualidade dos alimentos. Entretanto, dados de desempenho são insuficientes para se detectar as possíveis interações que possam ocorrer no ambiente ruminal. O objetivo do presente trabalho foi avaliar os possíveis efeitos associativos nas concentrações de ácidos graxos voláteis (AGVs), nitrogênio amoniacal (N-NH3) e pH da fração líquida remanescente da digestão da matéria seca (MS) de volumosos exclusivos (cana-de-açúcar= CN; capim-elefante com 60 dias= CP60 e 180 dias= CP180 de crescimento; e silagem de milho= SIL) e suas combinações (cana-de-açúcar+silagem de milho= CNSIL; cana-de-açúcar+capim-elefante-60d= CNCP60; cana-de-açúcar+capim-elefante-180d= CNCP180; silagem de milho+capim-elefante-60d= SILCP60; silagem de milho+capim-elefante-180d= SILCP180) na proporção de 50% na MS, que levam a resultados de desempenhos positivos ou negativos de bovinos. As concentrações de AGVs, N-NH3 e pH dos tratamentos foram: CN= 56,9 mmol L-1, 50,1 mg dL-1, 5,7; CNSIL= 61,4 mmol L-1, 50,7 mg dL-1, 5,8; CNCP60= 54,7 mmol L-1, 47,6 mg dL-1, 5,8; CNCP180= 45,4 mmol L-1, 49,4 mg dL-1, 6,0; SIL= 57,2 mmol L-1, 54,0 mg dL-1, 5,8; SILCP60= 57,1 mmol L-1, 53,1 mg dL-1, 5,9; SILCP180= 55,9 mmol L-1, 52,3 mg dL-1, 6,0; CP60= 58,1 mmol L-1, 49,4 mg dL-1, 5,9; CP180= 44,0 mmol L-1, 46,4 mg dL-1, 6,1. Os carboidratos não estruturais e amido, aliados à fibra e proteína, contribuíram para que ocorresse o efeito associativo positivo na mistura 50:50 cana/silagem. Isso pode ter propiciado os melhores resultados de desempenho em bovinos devido ao elevado padrão fermentativo.

Valor nutritivo e estudo cinético do trato digestivo de dietas contendo grãos secos ou ensilados de sorgo de baixo e alto tanino para eqüinos

Quatro éguas sem raça definida (idade e peso corporal médios de seis anos e 400 kg) foram distribuídas em delineamento experimental em quadrado latino para se avaliar o valor nutritivo e o estudo cinético do trato digestivo de grãos secos ou ensilados de sorgo de baixo e alto conteúdos de tanino na alimentação de eqüinos. Os tratamentos consistiram de dietas contendo dois híbridos de grãos de sorgo (baixo e alto níveis de tanino) e dois métodos de conservação (secos e ensilados). As dietas foram isoprotéicas (12,4% PB), com ingestão diária de MS estabelecida em 1,5% PV (relação feno:concentrado de 50: 50). Os parâmetros de trânsito gastrintestinal avaliados foram: k1 (taxa de passagem pelo intestino grosso), k2 (taxa de passagem pelo estômago), TT (tempo de trânsito), TMR (tempo médio de retenção) e TMRT (tempo médio de retenção total). Os tratamentos não afetaram os coeficientes de digestibilidade aparente (CDa) da MS e do amido, cujos valores médios foram 54,04 e 98,91%, respectivamente. Verificou-se efeito benéfico da ensilagem dos grãos de sorgo de alto conteúdo de tanino sobre a digestibilidade da PB e FDN. A CDa da PB e FDN para a dieta contendo grãos secos de sorgo de alto teor de tanino foi de 49,76 e 32,20% e para as dietas com grãos de sorgo de baixo conteúdo de tanino (seco ou ensilado) e grãos ensilados de sorgo de alto teor de tanino foi de 65,63 e 43,32%, respectivamente. Obteve-se somente efeito do método de conservação dos grãos de sorgo (secos vs ensilados) sobre o TMR, em que o valor para as dietas com silagens de grãos ensilados e secos foi, respectivamente, de 40,08 e 37,9h. Concluiu-se que os grãos de sorgo secos de alto teor de tanino não devem ser usados como principal grão energético nos concentrados para eqüinos, por diminuírem a digestibilidade da proteína e fibra.

Rendimento dos componentes não-carcaça de cordeiros alimentados com silagem de milho ou cana-de-açúcar e dois níveis de concentrado

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

Ultrastructural evidences of the occurrence of digestion and absorption of organic solutes in bees ileum (Melipona quadrifasciata anthidioides - Hymenoptera, Apidae)

The ultrastructural aspects of the ileum of Melipona quadrifasciata anthidioides, a stingless bee whose workers obtain their protein requirements from pollen, present morphological evidences of digestion and absorption. These evidences are represented by special relationships between food particles and the bacterial nora present and between their assemblage and the ileum wall, mainly in the ileum three anterior fourths. The apical features of the epithelium also are indicative of organic material absorption.

Analytical procedure for total mercury determination in fishes and shrimps by chronopotentiometric stripping analysis at gold film electrodes after microwave digestion

A method for the total mercury determination in fish and shrimps employing chronopotentiometric stripping analysis on gold film electrodes is described. Fish and shrimp tissues were digested using a microwave oven equipped with closed vessels. We developed a microwave heating program which decomposed all the samples employing diluted nitric acid and hydrogen peroxide. The proposed method was validated by analyzing a certified reference material and then applied for different fish species from fresh water and seawater acquired in local markets of São Paulo city, Brazil. The Brazilian legislation establishes 0.5 and 1 mg per kilogram of fish as upper limit of mercury for omnivorous and predator species, respectively. Except for blue shark tissues, the mercury content was situated below 0.5 mu g g(-1) for all the analyzed samples. The detection limit of the proposed method was calculated as 5 ng g(-1) of sample utilizing 5 minutes of electrodeposition (+300 mV vs. Ag/AgCl) on the gold electrode. (c) 2006 Elsevier Ltd. All rights reserved.

Effect of anaerobic digestion and initial pH on metal bioleaching from sewage sludge

The effects of anaerobic digestion and initial pH on the bioleaching of metals from sewage sludge were investigated in shake flask experiments. A strain of Acidithiobacillus thiooxidans was employed in the assays using secondary and anaerobic sludges, which resulted in similar solubilization yields of the metals chromium, copper, lead, nickel, and zinc for both the sludges investigated. The effect of initial pH (7.0 and 4.0) on metal bioleaching was assayed by using the anaerobic sludge inoculated with indigenous sulfur-oxidizing thiobacilli. Although the time required to reach the end of the experiment (final pH close to 1.0) was shortened at initial pH of 4.0, final metal solubilization was not significantly different for both initial pH values, resulting in higher solubilization yields for copper, nickel, and zinc (higher than 80%). Chromium and lead presented solubilization yields close to 50%. The results obtained in this work showed that the metal bioleaching process can be applied to sewage sludge regardless of the type of sludge and without the requirement of pH adjustment.

Chitinolytic activities in the gut of Aedes aegypti (Diptera : Culicidae) larvae and their role in digestion of chitin-rich structures

Mosquito larvae are believed to be capable of digesting chitin, an insoluble polysaccharide of N-acetylglucosamine, for their nutritional benefit. Studies based on physiological and biochemical assays were conducted in order to detect the presence of chitinase activities in the gut of the detritus-feeding Aedes aegypti larvae. Larvae placed for 24 h in suspensions of chitin azure were able to digest the ingested chitin. Semi-denaturing PAGE using glycol chitin and two fluorogenic substrate analogues showed the presence of two distinct chitinase activities: an endochitinase that catalyzed the hydrolysis of chitin and an endochitinase that cleaved the short substrates [4MU(GlcNAc)(3)] and [4MU(GlcNAc)(2)] that hydrolyzed the chitobioside [4MU(GlcNAc)(2)]. The endochitinase had an extremely broad pH-activity against glycol chitin and chitin azure, pH ranging from 4.0 to 10.0. When the substrate [4MU(GlcNAc)(3)] was used, two activities were observed at pH ranges 4.0-6.0 and 8.0-10.0. Chitinase activity against [4MU(GlcNAc)(3)] was detected throughout the gut with the highest specific activity in the hindgut. The pH of the gut contents was determined by observing color changes in gut after feeding the larvae with color indicator dyes. It was observed a correlation between the pH observed in the gut of feeding larvae (pH 10-6.0) and the optimum pH for gut chitinase activities. In this work, we report that gut chitinases may be involved in the digestion of chitin-containing structures and also in the partial degradation of the chitinous peritrophic matrix in the hindgut. (C) 2003 Elsevier B.V. All rights reserved.