Dermatose responsiva à biotina em cão

Os transtornos da pele e dos pelos são parte importante na prática clínica de pequenos animais. Numerosos fatores nutricionais afetam a homeostase, a qualidade e o aspecto da pelagem. As vitaminas do complexo B incluem compostos hidrossolúveis necessários como coenzimas em diversas funções celulares envolvidas no metabolismo energético e na síntese tecidual. A biotina, em especial, é necessária nas reações de carboxilação, participando da síntese de ácidos graxos, aminoácidos e purinas pelo tecido epitelial. Uma cadela com quadro de cistite recorrente e tumor venéreo transmissível foi tratada com antibioticoterapia prolongada e quimioterapia. Após alguns meses de tratamento, foram observadas lesões no plano nasal e nos coxins plantar e palmar, caracterizadas por hiperceratose, espessamento, fissuras, sangramento e inflamação. O paciente recebeu suplementação de 15mg de biotina por via oral (equivalente a 1,4mg kg-1 de peso corporal), uma vez por dia, durante 60 dias, havendo importante regressão das lesões. Sugere-se que, sob antibioticoterapia e doença, a síntese intestinal de biotina possa não ter sido suficiente, sendo necessária sua suplementação.

Milk fatty acid characterization and genetic parameter estimates for milk conjugated linoleic acid in buffaloes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise de fluxos metabólicos para otimização da síntese do antibiótico cosmomicina por Streptomyces olindensis ICB20

Metabolic flux analysis (MFA) is a powerful tool for analyzing cellular metabolism. In order to control the growth conditions of a specific organism, it is important to have a complete understanding of its MFA. This would allowed us to improve the processes for obtaining products of interest to human and also to understand how to manipulate the genome of a cell, allowing optimization process for genetic engineering. Streptomyces olindensis ICB20 is a promising producer of the antibiotic cosmomycin, a powerful antitumor drug. Several Brazilian researchers groups have been developing studies in order to optimize cosmomycin production in bioreactors. However, to the best of our knowledge, nothing has been done on metabolic fluxes analysis field. Therefore, the aim of this work is to identify several factors that can affect the metabolism of Streptomyces olindensis ICB20, through the metabolic flux analysis. As a result, the production of the secondary metabolite, cosmomycin, can be increased. To achieve this goal, a metabolic model was developed which simulates a distribution of internal cellular fluxes based on the knowledge of metabolic pathways, its interconnections, as well as the constraints of microorganism under study. The validity of the proposed model was verified by comparing the computational data obtained by the model with the experimental data obtained from the literature. Based on the analysis of intracellular fluxes, obtained by the model, an optimal culture medium was proposed. In addition, some key points of the metabolism of Streptomyces olindensis were identified, aiming to direct its metabolism to a greater cosmomycin production. In this sense it was found that by increasing the concentration of yeast extract, the culture medium could be optimized. Furthermore, the inhibition of the biosynthesis of fatty acids was found to be a interesting strategy for genetic manipulation. Based on the metabolic model, one of the optimized medium conditions was experimentally tested in order to demonstrate in vitro what was obtained in silico. It was found that by increasing the concentration of yeast extract in the culture medium would induce to an increase of the cosmomycin production

Low protein diet confers resistance to the inhibitory effects of interleukin1 beta on insulin secretion in pancreatic islets

High protein content in the diet during childhood and adolescence has been associated to the onset insulin-dependent diabetes mellitus. We investigated the effect of interleukin-1 beta (IL-I beta) on insulin secretion, glucose metabolism, and nitrite formation by islets isolated from rats fed with normal protein (NP, 17%) or low protein (LP, 6%) after weaning. Pretreatment of islets with IL-1 beta for 1 h or 34 h inhibited the insulin secretion induced by glucose in both groups, but it was less marked in LP than in NP group. Islets from LP rats exhibited a decreased IL-1 beta -induced nitric oxide (NO) production, lower inhibition of D-[(UC)-C-14]-glucose oxidation to (CO2)-C-14, and less pronounced effect of IL-1 beta on alpha -ketoisocaproic acid-induced insulin secretion than NP islets. However, when the islets were stimulated by high concentrations of K+ the inhibitory effect of IL-1 beta on insulin secretion was not different between groups. In conclusion, protein restriction protects beta -cells of the deleterious effect of IL-1 beta, apparently, by decreasing NO production. The lower NO generation in islets from protein deprived rats may be due to increased free fatty acids oxidation and consequent alteration in Ca2+ homeostasis. (C) 2001 Elsevier B.V. All rights reserved.

Fatty acid composition of mid-trimester amniotic fluid in women of different ethnicities

Objective: To determine whether the fatty acid composition of mid-trimester amniotic fluid differs by ethnicity and pregnancy outcome. Methods: Fatty acid composition was analyzed by gas chromatography in 198 women undergoing amniocentesis at 15-19 weeks gestation. Cytokine levels were determined by ELISA in a subgroup of 52 subjects. Results: The major fatty acids detected were palmitic acid (31.8%) and stearic acid (31.5%). The n-6 polyunsaturated fatty acids (PUFA), linoleic acid (LA, 18: 2) and arachidonic acid (AA, 20: 4), were 11.3%, while the n-3 PUFA fatty acids, alpha linolenic acid (ALA, 18: 3) and docosahexaenoic acid (DHA, 22: 6), were 3.8% of the total. Palmitic acid was a higher percentage in Asians (40.5%) and Whites (34.5%) than in Blacks (22.2%) and Hispanics (23.7%) (p <= 0.0012). Oleic acid (18:1 n-9) was a higher percentage in Blacks (12.2%) and Hispanics (12.1%) than in Whites (9.2%) or Asians (7.5%) (<= 0.0002). LA and AA were higher in Blacks (9.0%, 5.4%) and Hispanics (8.6%, 4.1%) than in Whites (6.1%, 3.7%) and Asians (5.5%, 2.9%) (p <= 0.0002). DHA did not differ among the ethnic groups or according to pregnancy outcome. A reduced palmitic acid percentage was identified in the six women with preeclampsia (p = 0.0233). Tumor necrosis factor-alpha levels were inversely proportional to the palmitic acid percentage (p = 0.0275) and positively associated with the percentages of stearic (18:0) (p = 0.0132) and oleic (p = 0.0290) acids. Conclusions: Amniotic fluid fatty acid composition differed among the ethnic groups and may influence inflammatory mediator production and susceptibility to preeclampsia.

Função ovariana de novilhas Nelore alimentadas com dieta suplementada com gordura protegida ruminal

O objetivo deste trabalho foi avaliar o efeito da suplementação alimentar com gordura protegida ruminal sobre as estruturas ovarianas e sobre a concentração sérica de progesterona, em novilhas Nelore mantidas em pasto. Quarenta novilhas foram divididas em dois grupos: um suplementado com gordura protegida Megalac-E (G); e outro sem suplementação de gordura (C). O grupos foram avaliados em delineamento crossover. Utilizaram-se dietas isoenergéticas e isoproteicas. Após 15 dias de suplementação, os animais foram submetidos a um protocolo hormonal, para avaliação da influência da suplementação com gordura no metabolismo da progesterona. Para isto, em um dia aleatório do ciclo (D0), inseriu-se um implante intravaginal de liberação de progesterona (CIDR), e aplicou-se prostaglandina F2α (PGF2α, i.m.). No D7, o implante foi retirado, e outra aplicaηão de PGF2α foi realizada. No D18, foi feita uma nova aplicaηão de PGF2α e, então, foram observados diariamente os exames ultrassonográficos ovarianos e a ocorrência de estro. Para o ensaio com progesterona, colheu-se sangue 4 dias após a inserção do implante e, novamente, 7 e 14 dias após a ovulação. A concentração de progesterona sérica no D4 foi maior no grupo G. Não houve diferença nas concentrações séricas de progesterona 7 e 14 dias após a ovulação, nem no diâmetro do folículo ovulatório, nem no volume luteal. A suplementação com Megalac-E altera o metabolismo de progesterona, mas não altera a função ovariana em novilhas zebuínas em pasto.

Aplicações clínicas da suplementação de L-carnitina

A carnitina, uma amina quaternária (3-hidroxi-4-N-trimetilamino-butirato), é sintetizada no organismo (fígado, rins e cérebro) a partir de dois aminoácidos essenciais: lisina e metionina, exigindo para sua síntese a presença de ferro, ácido ascórbico, niacina e vitamina B6. Tem função fundamental na geração de energia pela célula, pois age nas reações transferidoras de ácidos graxos livres do citosol para mitocôndrias, facilitando sua oxidação e geração de adenosina Trifosfato. A concentração orgânica de carnitina é resultado de processos metabólicos - como ingestão, biossíntese, transporte dentro e fora dos tecidos e excreção - que, quando alterados em função de diversas doenças, levam a um estado carencial de carnitina com prejuízos relacionados ao metabolismo de lipídeos. A suplementação de L-carnitina pode aumentar o fluxo sangüíneo aos músculos devido também ao seu efeito vasodilatador e antioxidante, reduzindo algumas complicações de doenças isquêmicas, como a doença arterial coronariana, e as conseqüências da neuropatia diabética. Por esse motivo, o objetivo do presente trabalho foi descrever possíveis benefícios da suplementação de carnitina nos indivíduos com necessidades especiais e susceptíveis a carências de carnitina, como os portadores de doenças renais, neuropatia diabética, síndrome da imunodefeciência adquirida e doenças cardiovasculares.

Fatty acid profile of feedlot Brangus bullocks fed with monensin or polyclonal antibodies.

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

Structural insights for fatty acid binding in a Lys49-phospholipase A(2): crystal structure of myotoxin II from Bothrops molojeni complexed with stearic acid

The crystal structure of dimeric Lys49-phospholipase A2 myotoxin-II from Bothrops moojeni (MjTX-II) co-crystallized with stearic acid (C18H36O2) has been determined at a resolution of 1.8 angstrom. The electron density maps permitted the unambiguous inclusion of six stearic acid molecules in the refinement. Two stearic acid molecules could be located in the substrate-binding cleft of each monomer in positions, which favor the interaction of their carboxyl groups with active site residues. The way of binding of stearic acids to this Lys49-PLA(2)s is analogous to phospholipids and transition state analogues to catalytically active PLA(2)s. Two additional stearic acid molecules were located at the dimer interface region, defining a hitherto unidentified acyl-binding site on the protein surface. The strictly conserved Lys122 for Lys49-PLA(2)s may play a fundamental role for stabilization of legend-protein complex. The comparison of MjTX-II/satiric acid complex with other Lys-PLA(2)s structures whose putative fatty acids were located at their active site is also analysed. Molecular details of the stearic acid/protein interactions provide insights to binding in croup I/II PLA(2)s and to the possible interactions of Lys49-PLA(2)s with target membranes. (c) 2004 Elsevier SAS. All rights reserved.

Metabolic responses to glucoprivation induced by 2-deoxy-D-glucose in Brycon cephalus (Teleostei, Characidae)

The effects of functional cytoglucopenia provoked by 2-deoxy-D-glucose (2-DG) were studied in adult Brycon cephalus, an omnivorous fish from the Amazon Basin in Brazil. Glycogen content in liver and muscle as well as plasmatic glucose, free fatty acids (FFA), insulin, and glucagon were measured. After 48 h fasting, an intraperitoneal saline injection (NaCl 0.6 g/100 ml) was administered to control fish, whereas the experimental group received 2-DG, dissolved in saline, in the dosage of 80 mg/kg (0.487 mmol/kg) or 150 mg/kg (0.914 mmol/kg) body weight; injection volume was 5 ml in all treatments. Blood and tissue samples were taken immediately before, and 2, 8, 10, and 24 h after administration of the drug or saline. Fish injected with both doses of 2-DG showed a marked increase in glycemia levels. Liver and muscle glycogen decreased after 2-DG administration and reached their lowest values 10-24 h after injection, while in control animals no significant changes were observed. Elevation in plasma glucagon was observed only in response to the maximum dosage of 2-DG administered, especially 10 h and 24 h post-injection. Plasma insulin levels were lower in animals treated with the glucose analogue but only statistically significant 24 h after drug administration. In conclusion, the administration of the non-metabolizable glucose analogue 2-DG in B. cephalus is a stimulus to generate responses towards an increase in the glucose available to tissues, which is a characteristic of a fasting situation. All the above data support the interest of 2-DG administration as a model to study carbohydrate metabolism adjustment mechanisms in fish.

Metabolic changes in Brycon cephalus (Teleostei, Characidae) during post-feeding and fasting

Metabolic changes during the transition from post-feeding to fasting were studied in Brycon cephalus, an omnivorous teleost from the Amazon Basin in Brazil. Body weight and somatic indices (liver and digestive tract), glycogen and glucose content in liver and muscle, as well as plasma glucose, free fatty acids (FFA), insulin and glucagon levels of B. cephalus, were measured at 0, 12, 24, 48, 72, 120, 168 and 336 h after the last feeding. At time 0 h (the moment of food administration, 09.00 h) plasma levels of insulin and glucagon were already high, and relatively high values were maintained until 24 h post-feeding. Glycemia was 6.42 +/- 0.82 mM immediately after food ingestion and 7.53 +/- 1.12 MM at 12 h. Simultaneously, a postprandial replenishment of liver and muscle glycogen reserves was observed. Subsequently, a sharp decrease of plasma insulin occurred, from 7.19 +/- 0.83 ng/ml at 24 h of fasting to 5.27 +/- 0.58 ng/ml at 48 h. This decrease coincided with the drop in liver glucose and liver glycogen, which reached the lowest value at 72 h of fasting (328.56 +/- 192.13 and 70.33 +/- 14.13 mumol/g, respectively). Liver glucose increased after 120 h and reached a peak 168 h post-feeding, which suggests that hepatic gluconeogenesis is occurring. Plasma FFA levels were low after 120 and 168 h and increased again at 336 h of fasting. During the transition from post-feeding to fast condition in B. cephalus, the balance between circulating insulin and glucagon quickly adjust its metabolism to the ingestion or deprivation of food. (C) 2002 Elsevier B.V. All rights reserved.

Proteomic analysis of kidney in rats chronically exposed to fluoride

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