Sheep abortion associated with Neospora caninum in Mato Grosso do Sul, Brazil

Canids are the main hosts of Neospora caninum, but cattle, (sheep, goats and horses may serve as intermediary hosts. N. caninum infection of pregnant intermediary hosts may provoke abortion and neonatal infections. This study is the first to report lamb abortion associated with N. caninum in Mato Grosso do Sul. Epidemiological data were obtained from interviews with sheep producers. For microscopic examination, fragments of different organs removed from 4 sheep fetuses, aborted and necropsied, were fixed in 10% formaldehyde, embedded in paraffin and subjected to the hematoxylin-eosin staining protocol and immunohistochemistry (IHC) to test for N. caninum and Toxoplasma gondii. The abortion outbreak studied was reported from a herd of 268 Santa Inês sheep (including 186 pregnant ewes), with 10 abortion cases in the last third of gestation. Four fetuses were examined, 3 from a same ewe. At necropsy, one fetus exhibited crackling in the lung and all its organs were reddish. Histological findings detected mononuclear cell infiltrates among myocardium fibers and around blood vessels, in addition to circular structures with basophilic points resembling protozoans. IHC tests revealed strongly positive staining for N. caninum and weakly positive for T. gondii, characterizing N. caninum infection.

Effect of oral administration of Propionibacterium acnes on growth performance, DTH response and anti-OVA titers in goat kids

Immunostimulants are susbstances that stimuli the response of effector cells to activate the immune response such as antigen uptake, cytokine release or antibody response. These substances can increase resistence to infection by different types of microorganisms, reducing dependence of antibiotics used in livestock animals. Recent reports have demonstrated the positive effect of Propionibacterium acnes (P. acnes) to control animal diseases. In this study, we evaluated the effect of the non-specific immunostimulant P. acnes on immunological functions and growth performance in goat kids. Twenty five goat kids served as control group (A) and another 25 animals received P. acnes being the experimental group (B). Kids were challenged with ovalbumin (OVA) to assess humoral immunity. To assess in vivo cell immunity, delayed type hypersensitivity (DTH) test with phytohemagglutinin (PHA) was used, clinical signs and body weight were recorded each week until 9 weeks of age when the experiment ended. Blood samples were obtained to analyze serum proteins fractions and anti-OVA specific antibodies. No clinical signs of disease and no differences (p>0.05) on body weight between groups were recorded (7.32±0.81 kg in group A, 7.13±0.65 kg in group B). Goat kids from group B had more total protein (59.8±5g/l) and albumin levels (32.8±3.3g/l) than goat kids from group A (56.6±5.7 g/l, 29.6±3.9 g/l respectively) (p<0.05). DTH response in goat kids from group B on day 42 was higher (p<0.05) than group A. At day 63, goat kids from group receiving P. acnes had higher percentage (85.4) of anti-OVA IgM titers (p<0.05) than control group (57.7). In conclusion, the results showed that oral administration of P. acnes to goat kids improved some aspects of the immune system of the animals and it could be used to control goat diseases.

Diffusion Tensor Imaging as a Diagnostic and Research Tool: A Study on Preterm Infants

Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique. DTI is based on free thermal motion (diffusion) of water molecules. The properties of diffusion can be represented using parameters such as fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, which are calculated from DTI data. These parameters can be used to study the microstructure in fibrous structure such as brain white matter. The aim of this study was to investigate the reproducibility of region-of-interest (ROI) analysis and determine associations between white matter integrity and antenatal and early postnatal growth at term age using DTI. Antenatal growth was studied using both the ROI and tract-based spatial statistics (TBSS) method and postnatal growth using only the TBSS method. The infants included to this study were born below 32 gestational weeks or birth weight less than 1,501 g and imaged with a 1.5 T MRI system at term age. Total number of 132 infants met the inclusion criteria between June 2004 and December 2006. Due to exclusion criteria, a total of 76 preterm infants (ROI) and 36 preterm infants (TBSS) were accepted to this study. The ROI analysis was quite reproducible at term age. Reproducibility varied between white matter structures and diffusion parameters. Normal antenatal growth was positively associated with white matter maturation at term age. The ROI analysis showed associations only in the corpus callosum. Whereas, TBSS revealed associations in several brain white matter areas. Infants with normal antenatal growth showed more mature white matter compared to small for gestational age infants. The gestational age at birth had no significant association with white matter maturation at term age. It was observed that good early postnatal growth associated negatively with white matter maturation at term age. Growth-restricted infants seemed to have delayed brain maturation that was not fully compensated at term, despite catchup growth.

Effects of iron-ore particles on propagule release, growth and photosynthetic performance of Sargassum vulgare C. Agardh (Phaeophyta, Fucales)

The effect of iron-ore particles on the propagule release and growth of Sargassum vulgare C. Agardh was tested under treatments with different concentrations of iron-ore particles: 0.1, 1.0, 10.0 g.L-1 and a solution of 10.0 g.L-1 of filtered iron-ore. Filtered seawater was used as control. Photosynthesis vs. irradiance (P-I) curves were calculated for S. vulgare in the presence of iron-ore and in seawater. There was no significant difference in the number of propagules released by the receptacles or in the percentage of zygote formation among the treatments. The released propagules acted like aggregation centers for the particles, those more heavily coated with iron (10.0 g.L-1) exhibiting the highest sinking velocity (32.6 ± 9.8 mm.s-1). No difference in the percentage of embryo survival was detected during the first week in culture. After four weeks the embryos grew in all treatments. Maximum frond development (5.3 ± 0.8 mm) was observed in treatment of seawater enriched with Provasoli's medium (PES) while initial filoids did not develop in three treatments without PES and with iron-ore (0.1 g.L-1, 1.0 g.L-1 and 10.0 g.L-1). The values for Pmax, alpha and respiration showed no significant differences between the P-I curves. The calculated value for I K was 106.26 µmol.m-2.s-1 to the control curve and 981.49 µmol.m-2.s-1 to the iron-ore curve. The results indicate that the iron-ore particles in high concentration reduce the growth of S. vulgare as they recovered the embryos, juveniles and young plants. In contrast, the presence of the particles did not affect the release of gametes, percentage of zygote formation or the percentage of embryo survival.

The Association between Growth and Neurodevelopment in Very Preterm Infants – A Follow-up Study in the PIPARI Study

Placental insufficiency is one major cause of intrauterine growth restriction and also relates to neurodevelopment. Preterm infants with very low birth weight are at risk of postnatal growth restriction as well as neurodevelopmental impairments. However, the optimal postnatal growth for long-term neurodevelopment is still unclear. The objective of this study was thus to investigate the association between growth and neurodevelopment in very preterm infants. The study populations consisted of 83 (I), 55 (II), 36 (III) and 181 (IV) infants with very low birth weight (below 1501 grams), and very or extremely low gestational age (below 32 and 26 weeks). Foetal blood circulation in relation to two-year neurodevelopment and the association between early growth and brain maturation at term age were studied. Postnatal growth, and its association with five-year cognitive outcome, was analysed. Changes in foetal blood circulation related to placental insufficiency associated with an adverse two-year cognitive outcome. Early postnatal growth in extremely preterm infants was comparable to a similar Swedish cohort. Preterm infants with slow intrauterine growth had less mature brains at term age; rapid catch-up growth until term age did not eliminate this difference. Weight gain and head circumference growth from birth until two years of age associated positively with five-year cognitive outcome in appropriate for gestational age infants. In small for gestational age infants, head circumference growth from term age to four months (corrected age) associated positively with their five-year cognitive outcome. The association between postnatal growth and neurodevelopment was different for prenatally normally grown versus slow grown preterm infants.

Increase in skeletal muscle protein content by the ß-2 selective adrenergic agonist clenbuterol exacerbates hypoalbuminemia in rats fed a low-protein diet

This investigation examined how the nutritional status of rats fed a low-protein diet was affected when the animals were treated with the ß-2 selective agonist clenbuterol (CL). Males (4 weeks old) from an inbred, specific-pathogen-free strain of hooded rats maintained at the Dunn Nutritional Laboratory were used in the experiments (N = 6 rats per group). CL treatment (Ventipulmin, Boehringer-Ingelheim Ltd., 3.2 mg/kg diet for 2 weeks) caused an exacerbation of the symptoms associated with protein deficiency in rats. Plasma albumin concentrations, already low in rats fed a low-protein diet (group A), were further reduced in CL rats (A = 25.05 ± 0.31 vs CL = 23.64 ± 0.30 g/l, P<0.05). Total liver protein decreased below the level seen in either pair-fed animals (group P) or animals with free access to the low-protein diet (A = 736.56 ± 26 vs CL = 535.41 ± 54 mg, P<0.05), whereas gastrocnemius muscle protein was higher than the values normally described for control (C) animals (C = 210.88 ± 3.2 vs CL = 227.14 ± 1.7 mg/g, P<0.05). Clenbuterol-treated rats also showed a reduction in growth when compared to P rats (P = 3.2 ± 1.1 vs CL = -10.2 ± 1.9 g, P<0.05). This was associated with a marked decrease in fat stores (P = 5.35 ± 0.81 vs CL = 2.02 ± 0.16 g, P<0.05). Brown adipose tissue (BAT) cytochrome oxidase activity, although slightly lower than in P rats (P = 469.96 ± 16.20 vs CL = 414.48 ± 11.32 U/BAT x kg body weight, P<0.05), was still much higher than in control rats (C = 159.55 ± 11.54 vs CL = 414.48 ± 11.32 U/BAT x kg body weight, P<0.05). The present findings support the hypothesis that an increased muscle protein content due to clenbuterol stimulation worsened amino acid availability to the liver and further reduced albumin synthesis causing exacerbation of hypoalbuminemia in rats fed a low-protein diet.

Postnatal development of rats exposed to fluoxetine or venlafaxine during the third week of pregnancy

The aim of the present study was to compare the toxic effects of fluoxetine (F) (8 and 16 mg/kg) and venlafaxine (V) (40 and 80 mg/kg) administered during the third week of pregnancy on early development of rats. Both antidepressants were administered by gavage on pregnancy days 15 to 20 to groups of 10 to 12 animals each. Duration of gestation, food and water consumption, number of live pups and birth weight were recorded. Litters were culled to six pups at birth (day 1) and followed for growth until weaning (day 25). On day 60, a male and a female from each litter were injected with the 5-HT1 agonist, 5-methoxy-N,N-dimethyltryptamine (6 mg/kg, ip) and the serotonergic syndrome was graded. Fluoxetine but not venlafaxine reduced the duration of pregnancy when compared to the control (C) group (F = 21.1 days and C = 21.6 days, mean, P<0.02; maximum = 22 days and minimum = 21 days in both groups). The highest doses of both fluoxetine, 16 mg/kg (F16), and venlafaxine, 80 mg/kg (V80), reduced the food intake of pregnant rats, resulting in different rates of body weight gain during treatment (from pregnancy day 15 to day 20): F16 = 29.0 g, V80 = 28.7 g vs C = 39.5 g (median). Birth weight was influenced by treatment and sex (P<0.05; two-way ANOVA). Both doses of fluoxetine or venlafaxine reduced the body weight of litters; however, the body weight of litters from treated dams was equal to the weight of control litters by the time of weaning. At weaning there was no significant difference in weight between sexes. There was no difference among groups in number of live pups at birth, stillbirths, mortality during the lactation period or in the manifestation of serotonergic syndrome in adult rats. The occurrence of low birth weight among pups born to dams which did not show reduced food ingestion or reduction of body weight gain during treatment with lower doses of fluoxetine or venlafaxine suggests that these drugs may have a deleterious effect on prenatal development when administered during pregnancy. In addition, fluoxetine slightly but significantly affected the duration of pregnancy (about half a day), an effect not observed in the venlafaxine-treated groups.

Staircase in mammalian muscle without light chain phosphorylation

In disuse atrophied skeletal muscle, the staircase response is virtually absent and light chain phosphorylation does not occur. The purpose of the present study was to determine if staircase could be restored in atrophied muscle with continued absence of myosin light chain phosphorylation, by reducing what appears to be an otherwise enhanced calcium release. Control (untreated) and sham-operated female Sprague-Dawley rats were compared with animals after 2 weeks of complete inactivity induced by tetrodotoxin (TTX) application to the left sciatic nerve. In situ isometric contractile responses of rat gastrocnemius muscle were analyzed before and after administration of dantrolene sodium (DS), a drug which is known to inhibit Ca2+ release in skeletal muscle. Twitch active force (AF) was attenuated by DS from 2.2 ± 0.2 N, 2.7 ± 0.1 N and 2.4 ± 0.2 N to 0.77 ± 0.2 N, 1.05 ± 0.1 N and 1.01 ± 0.2 N in TTX (N = 5), sham (N = 11) and control (N = 7) muscles, respectively. Following dantrolene treatment, 10 s of 10-Hz stimulation increased AF to 1.32 ± 0.2 N, 1.52 ± 0.1 N and 1.45 ± 0.2 N for the TTX, sham and control groups, respectively, demonstrating a positive staircase response. Regulatory light chain (R-LC) phosphorylation was lower for TTX-treated (5.5 ± 5.5%) than for control (26.1 ± 5.3%) and sham (20.0 ± 5%) groups. There was no significant change from resting levels for any of the groups after DS treatment (P = 0.88). This study shows that treatment with dantrolene permits staircase in atrophied muscle as well as control muscle, by a mechanism which appears to be independent of R-LC phosphorylation.

New vaccine strategies against enterotoxigenic Escherichia coli: II: Enhanced systemic and secreted antibody responses against the CFA/I fimbriae by priming with DNA and boosting with a live recombinant Salmonella vaccine

The induction of systemic (IgG) and mucosal (IgA) antibody responses against the colonization factor I antigen (CFA/I) of enterotoxigenic Escherichia coli (ETEC) was evaluated in mice primed with an intramuscularly delivered CFA/I-encoding DNA vaccine followed by two oral immunizations with a live recombinant Salmonella typhimurium vaccine strain expressing the ETEC antigen. The booster effect induced by the oral immunization was detected two weeks and one year after the administration of the DNA vaccine. The DNA-primed/Salmonella-boosted vaccination regime showed a synergistic effect on the induced CFA/I-specific systemic and secreted antibody levels which could not be attained by either immunization strategy alone. These results suggest that the combined use of DNA vaccines and recombinant Salmonella vaccine strains can be a useful immunization strategy against enteric pathogens.

Bi-directional actions of estrogen on the renin-angiotensin system

Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE activity, was significantly reduced by estrogen treatment, further supporting the biochemical significance of estrogen's inhibition of ACE. In ovariectomized transgenic hypertensive (mRen2)27 rats submitted to estrogen replacement treatment for 3 weeks, ACE activity in plasma and tissue (aorta and kidney) and circulating Ang II levels were reduced, whereas circulating levels of angiotensin-(1-7) (Ang-(1-7) were increased. Ang-(1-7), the N-terminal fragment of Ang II, is a novel vasodilator and antihypertensive peptide. Thus, the net balance of these effects of estrogen on the renin-angiotensin vasoconstrictor/vasodilator system is to promote the antihypertensive effect.

Effects of prenatal exposure to a mild chronic variable stress on body weight, preweaning mortality and rat behavior

Early stimulation has been shown to produce long-lasting effects in many species. Prenatal exposure to some strong stressors may affect development of the nervous system leading to behavioral impairment in adult life. The purpose of the present work was to study the postnatal harmful effects of exposure to variable mild stresses in rats during pregnancy. Female Holtzman rats were submitted daily to one session of a chronic variable stress (CVS) during pregnancy (prenatal stress; PS group). Control pregnant rats (C group) were undisturbed. The pups of PS and C dams were weighed and separated into two groups 48 h after delivery. One group was maintained with their own dams (PS group, N = 70; C group, N = 36) while the other PS pups were cross-fostered with C dams (PSF group, N = 47) and the other C pups were cross-fostered with PS dams (CF group, N = 58). Pups were undisturbed until weaning (postnatal day 28). The male offspring underwent motor activity tests (day 28), enriched environment tests (day 37) and social interaction tests (day 42) in an animal activity monitor. Body weight was recorded on days 2, 28 and 60. The PS pups showed lower birth weight than C pups (Duncan's test, P<0.05). The PS pups suckling with their stressed mothers displayed greater preweaning mortality (C: 23%, PS: 60%; c2 test, P<0.05) and lower body weight than controls at days 28 and 60 (Duncan's test, P<0.05 and P<0.01, respectively). The PS, PSF and CF groups showed lower motor activity scores than controls when tested at day 28 (Duncan's test, P<0.01 for PS group and P<0.05 for CF and PSF groups). In the enriched environment test performed on day 37, between-group differences in total motor activity were not detected; however, the PS, CF and PSF groups displayed less exploration time than controls (Duncan's test, P<0.05). Only the PS group showed impaired motor activity and impaired social behavior at day 42 (Duncan's test, P<0.05). In fact, CVS treatment during gestation plus suckling with a previously stressed mother caused long-lasting physical and behavioral changes in rats. Cross-fostering PS-exposed pups to a dam which was not submitted to stress counteracted most of the harmful effects of the treatment. It is probable that prenatal stress plus suckling from a previously stressed mother can induce long-lasting changes in the neurotransmitter systems involved in emotional regulation. Further experiments using neurochemical and pharmacological approaches would be interesting in this model.

Obese women on a low energy rice and bean diet: effects of leucine, arginine or glycine supplementation on protein turnover

This study examined if leucine, arginine or glycine supplementation in adult obese patients (body mass index of 33 ± 4 kg/m²) consuming a Brazilian low energy and protein diet (4.2 MJ/day and 0.6 g protein/kg) affects protein and amino acid metabolism. After four weeks adaptation to this diet, each subject received supplements of these amino acids (equivalent to 0.2 g protein kg-1 day-1) in random order. On the seventh day of each amino acid supplementation, a single-dose 15N-glycine study was carried out. There were no significant differences in protein flux, synthesis or breakdown. The protein flux (grams of nitrogen, gN/9 h) was 55 ± 24 during the nonsupplemented diet intake and 39 ± 10, 44 ± 22 and 58 ± 35 during the leucine-, glycine- and arginine-supplemented diet intake, respectively; protein synthesis (gN/9 h) was 57 ± 24, 36 ± 10, 41 ± 22 and 56 ± 36, respectively; protein breakdown (gN/9 h) was 51 ± 24, 34 ± 10, 32 ± 28 and 53 ± 35, respectively; kinetic balance (gN/9 h) was 3.2 ± 1.8, 4.1 ± 1.7, 3.4 ± 2.9 and 3.9 ± 1.6. There was no difference in amino acid profiles due to leucine, arginine or glycine supplementation. The present results suggest that 0.6 g/kg of dietary protein is enough to maintain protein turnover in obese women consuming a reduced energy diet and that leucine, arginine or glycine supplementation does not change kinetic balance or protein synthesis.