The effect of changing the mode of ventilation on the arterial-to-end-tidal CO2 difference and physiological dead space in laterally and dorsally recumbent horses during halothane anesthesia

Objective - To evaluate the effect of changing the mode of ventilation from spontaneous to controlled on the arterial-to-end-tidal CO2 difference [P(a-ET)CO2] and physiological dead space (VD(phys)/VT) in laterally and dorsally recumbent halothane-anesthetized horses. Study Design - Prospective, experimental, nonrandomized trial. Animals - Seven mixed breed adult horses (1 male and 6 female) weighing 320 ± 11 kg. Methods - Horses were anesthetized in 2 positions - right lateral and dorsal recumbency - with a minimum interval of 1 month. Anesthesia was maintained with halothane in oxygen for 180 minutes. Spontaneous ventilation (SV) was used for 90 minutes followed by 90 minutes of controlled ventilation (CV). The same ventilator settings were used for both laterally and dorsally recumbent horses. Arterial blood gas analysis was performed every 30 minutes during anesthesia. End-tidal CO2 (PETCO2) was measured continuously. P(a-ET)CO2 and VD(phys)/VT were calculated. Statistical analysis included analysis of variance for repeated measures over time, followed by Student-Newman-Keuls test. Comparison between groups was performed using a paired t test; P < .05 was considered significant. Results - P(a-ET)CO2 and VD(phys)/VT increased during SV, whereas CV reduced these variables. The variables did not change significantly throughout mechanical ventilation in either group. Dorsally recumbent horses showed greater P(a-ET)CO2 and VD(phys)/VT values throughout. PaCO2 was greater during CV in dorsally positioned horses. Conclusions and Clinical Relevance - Changing the mode of ventilation from spontaneous to controlled was effective in reducing P(a-ET)CO2 and physiological dead space in both laterally and dorsally recumbent halothane-anesthetized horses. Dorsal recumbency resulted in greater impairment of effective ventilation. Capnometry has a limited value for accurate estimation of PaCO, in anesthetized horses, although it may be used to evaluate pulmonary function when paired with arterial blood gas analysis. © Copyright 2000 by The American College of Veterinary Surgeons.

Estimates of covariance functions for growth from birth to 630 days of age in Nelore cattle

Weight records of Brazilian Nelore cattle, from birth to 630 d of age, recorded every 3 mo, were analyzed using random regression models. Independent variables were Legendre polynomials of age at recording. The model of analysis included contemporary groups as fixed effects and age of dam as a linear and quadratic covariable. Mean trends were modeled through a cubic regression on orthogonal polynomials of age. Up to four sets of random regression coefficients were fitted for animals' direct and maternal, additive genetic, and permanent environmental effects. Changes in measurement error variances with age were modeled through a variance function. Orders of polyno-mial fit from three to six were considered, resulting in up to 77 parameters to be estimated. Models fitting random regressions modeled the pattern of variances in the data adequately, with estimates similar to those from corresponding univariate analysis. Direct heritability estimates decreased after birth and tended to be lowest at ages at which maternal effect estimates tended to be highest. Maternal heritability estimates increased after birth to a peak around 110 to 120 d of age and decreased thereafter. Additive genetic direct correlation estimates between weights at standard ages (birth, weaning, yearling, and final weight) were moderate to high and maternal genetic and environmental correlations were consistently high. © 2001 American Society of Animal Science. All rights reserved.

Protein Deficiency Attenuates the Effects of Alloxan on Insulin Secretion and Glucose Homeostasis in Rats

We have investigated the effect of alloxan on insulin secretion and glucose homeostasis in rats maintained on a 17% protein (normal protein, NP) or 6% protein (low protein, LP) diet from weaning (21 days old) to adulthood (90 days old). The incidence of alloxan diabetes was higher in the NP (3.5 times) than in the LP group. During an oral glucose tolerance test, the area under serum glucose curve was lower in LP (57%) than in NP rats while there were no differences between the two groups in the area under serum insulin curve. The serum glucose disappearance rate (Kitt) after exogenous insulin administration was higher in LP (50%) than in NP rats. In pancreatic islets isolated from rats not injected with alloxan, acute exposure to alloxan (0.05 mmol/L) reduced the glucose- or arginine-stimulated insulin secretion of NP islets by 78% and 56%, respectively, whereas for islets from LP rats, the reduction was 47% and 17% in the presence of glucose and arginine, respectively. Alloxan treatment reduced the glucose oxidation in islets from LP rats to a lesser extent than in NP islets (23% vs. 56%). In conclusion, alloxan was less effective in producing hyperglycemia in rats fed a low protein diet than in normal diet rats. This effect is attributable to an increased peripheral sensivity to insulin in addition to a better preservation of glucose oxidation and insulin secretion in islets from rats fed a low protein diet.

Utilização de NaCl no suplemento como alternativa para viabilizar o sistema de alimentação de bezerros em creep-feeding

Thirty two Canchim suckling calves, maintained on rotational grazing system of Brachiaria brizantha cv. Marandu, were divided in three groups corresponding to three evaluated treatments: control (without creep-feeding); SAL5 (addition of 5% of NaCl to concentrate fed in creep-feeding); and SAL10 (addition of 10% of NaCl to concentrate fed in creep-feeding). Feeding in a creep-feeding system lasted 90 days, divided in three subperiods of 30 days. The body weight gain was greater in the subperiods 1 and 2 for SAL10 and SAL5 treatments, respectively. There were no differences in the third subperiod and, in the overall period, the SAL10 treatment (0.91 kg.animal-1.day-1) was better than control treatment (0.81 kg,animal-1.day-1). The monthly remuneration provided by the treatments SAL5 e SAL10 related to the control group were-12.5 and 6.0%, respectively. The body weight differentials at weaning, compared to the control group, for creep-feeding provide a monthly net profit of 0, 0.6, 1.2, and 6.0% should be 10.8, 11.0, 11.2, and 12.8 kg.animal-1 for SAL5 and 7.6, 7.7, 7.8, and 9.0 kg.animal-1 for SAL10. It was concluded that the limited supplement intake in creep-feeding was necessary to obtain economic viability.

Estudo de modelo alternativo para estimação de componentes de (co)variância e predição de valores genéticos de características de crescimento em bovinos da raça Nelore

The objectives of this study were to estimate genetic parameters for non-standardized weights at nursing (PR120), at weaning (PR240), at yearling (PR365) and at post yearling (PR550), and to predict EPD's (expected progeny differences) for these traits using records from 29,769 Nellores. Covariance components and genetic parameters were estimated by mixed-model methodology, REML, using an animal model. Models for PR120, PR240, PR365 and PR455 included the random direct and maternal animal effects, the dam permanent environmental effect and the error. Fixed effects were contemporary group (CG) and age of cow at parturition (CIVP) and the covariate age of the calf at measuring. Two additional models for PR365, PR455 and PR550 analyses were used: the first included CG and CIVP, animal and maternal direct effect, residual and age of the calf (as covariate), and the second included CG and CIVP (as fixed effects), animal direct effect, residual and age of calf at measuring. Observed means±standard deviations were: 127±25kg (PR120); 191±34kg (PR240); 225±42kg (PR365); 266±51kg (PR455) and 310±56kg (PR550). From single-trait analyses, direct and maternal heritabilities for PR120, PR240, PR365 and PR455 were, respectively, .23 and .08; .19 and .10; .24 and .04; .30 and .04. Direct heritabilities were .39; .44 and .43, respectively, for PR365, PR455 and PR550. In the model without permanent effect, direct and maternal heritabilities for PR365, PR455 and PR550 were .25 and .08; .32 and .07; .38 and .03, respectively. When the estimates for standardized traits at the same period were compared, no differences in magnitude were found. Rank correlation had important changes when standardized and non-standardized traits were compared.

Metabolismo oxidativo de neutrófilos em ovelhas naturalmente infectadas por nematódeos gastrintestinais e correlação entre nível sérico de cortisol e carga parasitária

The relationships between neutrophils oxidative metabolism, cortisol serum levels and worm burden, estimated by fecal egg count (EPG), were studied in sheep naturally infected by gastrointestinal parasites at the end of pregnancy, during lactation, and after weaning. Twenty-two Suffolk sheep three to four year old, of same parity and season of parturition were used. Serum cortisol was determined by radioimmunoassay and the neutrophils oxidative metabolism by the nitroblue tetrazolium (NBT) reduction test. The highest EPG values were observed on the fifth week of lactation while the highest rates of cortisol and reduction of NBT occurred on the fourth week after weaning. A positive correlation (r = 0.52; P<0.01) was observed between the neutrophils capacity to reduce the NBT and the serum cortisol concentration in the pre-parturition period. Otherwise, the neutrophils oxidative metabolism decreased near to the parturition. A negative correlation (r = -0.39; P<0.01) between EPG and NBT reduction test was observed after weaning, which was coincident with the increase in the neutrophils capacity to reduce NBT, indicating that animals showing better immune response after weaning have neutrophils with higher oxidative metabolism and lower worm burden.

Uso do óxido nítrico em pediatria

Objective: To review the literature on inhaled nitric oxide and to describe its main clinical applications in pediatrics. Sources of data: A 10 year literature review with selection of the most important publications on inhaled nitric oxide, using the Medline and Cochrane Systematic Review databases. Summary of the findings: This review was organized as follows: introduction; metabolism and biological effects; clinical applications; dosage, gas administration and weaning; precautions and side-effects. Inhaled nitric oxide use was described in persistent pulmonary hypertension and hypoxia of the newborn, acute respiratory distress syndrome, primary pulmonary hypertension, heart surgery, chronic obstructive pulmonary disease, sickle cell anemia, and bronchospastic disease. Conclusions: Inhaled nitric oxide is a therapeutic approach with wide clinical applications in pediatrics. Its use is safe when administered in pediatric intensive care units under strict monitoring. As a pulmonary vasodilator, nitric oxide has beneficial effects on gas exchange and ventilation. Controlled trials, focusing on early gas administration should be performed under many clinical conditions, especially acute respiratory distress syndrome.

Utilization of fish protein hydrolysate in prepared diets for pacu, Piaractus mesopotamicus, larvae

Growth and survival rates of pacu, Piaractus mesopotamicus, larvae fed prepared diets containing different animal protein sources were evaluated. Four diets with the same level of crude protein (CP) (36%) and calories (4.02 kcal gross energy/g of diet) were fed to the larvae. Diets were formulated to contain one of four protein sources: (1) fish meal (FM), (2) tilapia residue silage (TS), (3) protein hydrolysate from tilapia residue (HT), and (4) eviscerated tilapia residue (HET). Larvae were fed Artemia nauplii for six days, prior to the start of the study, and the prepared diet was supplied from day 7 until the study concluded. Variance analysis showed no significant differences (P > 0.05) for survival rates and larval final lengths among treatments. However, final average weights were significantly different (P < 0.05 for larvae fed FM and HT. Average survival rates were relatively high and ranged from 68.1% to 73.9%. After the live food was replaced by prepared diets, no larval growth was observed for any treatment. Fish protein hydrolysate (HT and HET) and fish silage showed potential to be used as ingredients in the diet of pacu larvae. However, hydrolysate inclusion levels, processing methods to minimize nutrient lixiviation, and the best moment to replace live food with an inert diet (weaning) need further investigation. © 2003 by The Haworth Press, Inc. All rights reserved.

Evaluation of a protein deficient diet in rats through blood oxidative stress biomarkers

Protein malnutrition leads to functional impairment in several organs, which is not fully restored with nutritional recovery. Little is known about the role of oxidative stress in the genesis of these alterations. This study was designed to assess the sensitivity of blood oxidative stress biomarkers to a dietary protein restriction. Male Wistar rats were divided into two groups, according to the diet fed from weaning (21 days) to 60 day old: normal protein (17% protein) and low protein (6% protein). Serum protein, albumin, free fatty acid and liver glycogen and lipids were evaluated to assess the nutritional status. Blood glutathione reductase (GR) and catalase (CAT) activities, plasma total sulfhydryl groups concentration (TSG) as well as plasma thiobarbituric acid reactive substances (TBARs) and reactive carbonyl derivatives (RCD) were measured as biomarkers of the antioxidant system and oxidative damage, respectively. The glucose metabolism in soleus muscle was also evaluated as an index of stress severity imposed to muscular mass by protein malnutrition. No difference was observed in muscle glucose metabolism or plasma RCD concentration between both groups. However, our results showed that the low protein group had higher plasma TBARs (62%) concentration and lower TSG (44%) concentration than control group, indicating increased reactive oxygen species production in low protein group. The enhancement of erythrocyte GR (29%) and CAT (28%) activities in this group also suggest an adaptation to the stress generated by the protein deficiency. Taken together, the results presented here show that the biomarkers used were able to reflect the oxidative stress level induced by this specific protein deficient diet.

Acute and sustained effects of early administration of inhaled nitric oxide to children with acute respiratory distress syndrome

OBJECTIVE: To determine the acute and sustained effects of early inhaled nitric oxide on some oxygenation indexes and ventilator settings and to compare inhaled nitric oxide administration and conventional therapy on mortality rate, length of stay in intensive care, and duration of mechanical ventilation in children with acute respiratory distress syndrome. DESIGN: Observational study. SETTING: Pediatric intensive care unit at a university-affiliated hospital. PATIENTS: Children with acute respiratory distress syndrome, aged between 1 month and 12 yrs. INTERVENTIONS: Two groups were studied: an inhaled nitric oxide group (iNOG, n = 18) composed of patients prospectively enrolled from November 2000 to November 2002, and a conventional therapy group (CTG, n = 21) consisting of historical control patients admitted from August 1998 to August 2000. MEASUREMENTS AND MAIN RESULTS: Therapy with inhaled nitric oxide was introduced as early as 1.5 hrs after acute respiratory distress syndrome diagnosis with acute improvements in Pao(2)/Fio(2) ratio (83.7%) and oxygenation index (46.7%). Study groups were of similar ages, gender, primary diagnoses, pediatric risk of mortality score, and mean airway pressure. Pao(2)/Fio(2) ratio was lower (CTG, 116.9 +/- 34.5; iNOG, 62.5 +/- 12.8, p <.0001) and oxygenation index higher (CTG, 15.2 [range, 7.2-32.2]; iNOG, 24.3 [range, 16.3-70.4], p <.0001) in the iNOG. Prolonged treatment was associated with improved oxygenation, so that Fio(2) and peak inspiratory pressure could be quickly and significantly reduced. Mortality rate for inhaled nitric oxide-patients was lower (CTG, ten of 21, 47.6%; iNOG, three of 18, 16.6%, p <.001). There was no difference in intensive care stay (CTG, 10 days [range, 2-49]; iNOG, 12 [range, 6-26], p >.05) or duration of mechanical ventilation (TCG, 9 days [range, 2-47]; iNOG, 10 [range, 4-25], p >.05). CONCLUSIONS: Early treatment with inhaled nitric oxide causes acute and sustained improvement in oxygenation, with earlier reduction of ventilator settings, which might contribute to reduce the mortality rate in children with acute respiratory distress syndrome. Length of stay in intensive care and duration of mechanical ventilation are not changed. Prospective trials of inhaled nitric oxide early in the setting of acute lung injury in children are needed.

Neonatal rat exposure to pyrethroid and organophosphate insecticides: A physiological and biochemical trial of progeny

A manufactured product (Ectoplus®) composed by a cypermethrin (44.7%) and dichlorvos (4.2%) mixture was administered (10mg/kg/day, orally, by gavage) to pregnant rats, during the periods of gestation+lactation, gestation, and lactation. Control mothers received vehicle aqueous solution during the gestation+lactation period. With the progeny, in the 1-15 post-natal days (PNDI-15) there were observed alterations in the periods of occurrence of teeth, hair, unfolding of ears, and in the developmental period for following reflexes: postural, palmar grasp, negative geotaxis, and acoustic startle reflex. After weaning (PND21), there were observed the presence of cypermethrin and dichlorvos in the blood brain and liver; decrease in weight of liver, of cholinesterase activity in the plasma, liver, and brain, and hepatic metabolizing activity of drugs; alterations of levels of gamma glutamyl transferase enzymes, of creatinine, and of potassium in the serum of the animals. In conclusion, neonatal exposure to a formulated mixture of cypermethrin and dichlorvos is inductive to alterations in characteristics that indicate somatic and neuromuscular development of the progeny, and in certain biochemical parameters. The results suggest that enzymatic assessment associated with somatic and neuromotor assessment can be important markers of developmental characteristics in neonatal toxicity by pesticide formulations based on mixtures of insecticides.

Resistance of Santa Inês and Ile de France suckling lambs to gastrointestinal nematode infections.

A trial was carried out to determine the resistance to natural infection by gastrointestinal nematodes in 12 Santa Inês and nine Ile de France lambs before weaning. Faecal samples were obtained for faecal nematode egg counts (FEC). Blood samples were collected to determine packed cell volume (PCV), total plasma protein levels and peripheral eosinophil counts. Most Ile de France lambs (77.8%) were treated with an anthelmintic at 43 days of age, while 50% off Santa Inês lambs were treated at weaning, 57 days of age. The mean PCV values were normal in Santa Inês lambs, while in Ile de France lambs showed lower values reaching 22.3% at 43 days of age. The lowest mean plasma protein values were observed in Ile de France lambs (4.13 g/dl) at 43 days of age and in Santa Inês lambs (5.0 g/dl) at 57 days of age. Before weaning, Santa Inês lambs were susceptible to natural infections by gastrointestinal nematodes but with a greater capacity to stand the adverse effects of parasitism compared to Ile de France lambs.

Tendências genéticas para características relacionadas à velocidade de crescimento em bovinos nelore na região nordeste do brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Intravenous versus nebulized ceftazidime in ventilated piglets with and without experimental bronchopneumonia: Comparative effects of helium and nitrogen

Background: Lung deposition of intravenous cephalosporins is low. The lung deposition of equivalent doses of ceftazidime administered either intravenously or by ultrasonic nebulization using either nitrogen-oxygen or helium-oxygen as the carrying gas of the aerosol was compared in ventilated piglets with and without experimental bronchopneumonia. Methods: Five piglets with noninfected lungs and 5 piglets with Pseudomonas aeruginosa experimental bronchopneumonia received 33 mg/kg ceftazidime intravenously. Ten piglets with noninfected lungs and 10 others with experimental P. aeruginosa bronchopneumonia received 50 mg/kg ceftazidime by ultrasonic nebulization. In each group, the ventilator was operated in half of the animals with a 65%/35% helium-oxygen or nitrogen-oxygen mixture. Animals were killed, and multiple lung specimens were sampled for measuring ceftazidime lung tissue concentrations by high-performance liquid chromatography. Results: As compared with intravenous administration, nebulization of ceftazidime significantly increased lung tissue concentrations (17 ± 13 vs. 383 ± 84 μg/g in noninfected piglets and 10 ± 3 vs. 129 ± 108 μg/g in piglets with experimental bronchopneumonia; P < 0.001). The use of a 65%/35% helium-oxygen mixture induced a 33% additional increase in lung tissue concentrations in noninfected piglets (576 ± 141 μg/g; P < 0.001) and no significant change in infected piglets (111 ± 104 μg/g). Conclusion: Nebulization of ceftazidime induced a 5- to 30-fold increase in lung tissue concentrations as compared with intravenous administration. Using a helium-oxygen mixture as the carrying gas of the aerosol induced a substantial additional increase in lung deposition in noninfected piglets but not in piglets with experimental bronchopneumonia. © 2005 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.

Co-feeding of pacu, Piaractus mesopotamicus Holmberg (1887), larvae with Artemia naupili and a microencapsulated diet

Aiming at a precocious substitution of live prey by artificial diet, a 20-day experiment with pacu, Piaractus mesopotamicus, larvae using co-feeding and abrupt weaning strategies was set up. At the end of the experiment, larvae fed Artemia showed the best results (P < 0.05) in weight, total length and biomass, compared with other treatments. Larvae fed exclusively a microencapsulated diet never ingested the diet. Diet ingestion in co-fed and abrupt-weaned larvae was low, but did increase during the experiment; however, Artemia influenced diet ingestion on co-fed larvae. Careful considerations should be given to diet processing and formulation to ensure survival and growth of larvae fed exclusively on prepared diets. © 2005 by The Haworth Press, Inc. All rights reserved.