Timpanismo espumoso em bovinos leiteiros em pastagens de Trifolium spp. (Leg.Caesalpinoideae)

O pastejo de plantas leguminosas que provocam fermentação excessiva pode causar surtos de timpanismo e mortes em ruminantes. Em uma propriedade no município de São Francisco de Paula, Rio Grande do Sul, oito bovinos de um total de 66 morreram subitamente, ao haverem sido transferidos de um potreiro de campo nativo, para outro cuja pastagem era composta por Trifolium repens e Trifolium pratense. Os animais foram encontrados mortos no amanhecer do dia seguinte à transferência, não foram observados sinais clínicos prévios. Os principais achados macroscópicos incluíram aumento de volume abdominal, protrusão de vagina e língua, distensão ruminal, fígado de coloração pálida e aumento do baço. Na histologia, havia congestão e edema pulmonares e hiperplasia linfóide difusa e acentuada no baço. A evidência de ingestão das leguminosas associada aos achados patológicos e à ausência de microrganismos no exame bacteriológico confirmaram o diagnóstico de timpanismo.

Sheep production as a Senecio spp. control tool

Since poisoning by Senecio spp. is one of the main causes of cattle death in southern Brazil, control of these plants is a priority for the local livestock production. After the pasture has been mowed, grazing by 16 sheep was efficient for controlling Senecio brasiliensis and Senecio madagascariensis populations in a 5.5-hectare area that had long been severely infested with these species. A total of 28,629 plants among S. brasiliensis (flower-of-souls, 10,122) and S.madagascariensis (fireweed, 18,507) were almost completely eliminated in a two-year period. The number of sheep was kept at 3.0 stock units/ha, but a variable number of cattle were temporarily stocked according to pasture availability. The major sanitary practice applied to the sheep was anthelmintic administration. Liver biopsies taken from sheep and cattle before and after experimental period didn't reveal any change associable with seneciosis. The performance levels of the sheep were comparable to those observed in flocks managed under traditional extensive grazing systems in southern Brazil.

GERMINACIÓN Y EMERGENCIA DE Megathyrsus maximus VAR.maximus

RESUMEN Se estudió la germinación de semillas de Megathyrsus maximus al exponerlas a altas temperaturas y el efecto de diferentes profundidades de siembra y cantidades de residuos de cosecha en la emergencia de las plántulas. En laboratorio, se determinó la germinación y biomasa de semillas con y sin glumas y glumelas, expuestas a 0, 40, 60, 80 y 100 oC durante cinco minutos. Se realizaron dos experimentos en invernáculo para evaluar la emergencia de la maleza, primero a diferentes profundidades de siembra: 0, 0.5, 1, 2, 3, 4, 5, 7 y 8 cm. Posteriormente, se evaluó emergencia con diferentes cantidades de residuos de cosecha: 0, 5, 8, 11, 13, 15 y 18 t ha-1. Los resultados de los ensayos de temperatura se analizaron mediante análisis de covarianza y los datos de los ensayos de invernáculo mediante regresión. Los máximos porcentajes de germinación para semillas con y sin glumas y glumelas se obtuvieron a 40 oC y fueron del 35 y 48%, respectivamente; los mínimos valores se registraron a los 80 oC y fueron del 7 y 28%, respectivamente. La profundidad de siembra afectó la emergencia: un 51% se registró en el testigo, valor que disminuyó al 23,3% a los 7 cm y a 0% a los 8 cm. Los residuos de cosecha también afectaron la emergencia: con 0 a 18 t ha-1, esta disminuyó del 64,8 al 0%. Puede concluirse que las estrategias implementadas en el manejo del cultivo de caña de azúcar afectarán la germinación y emergencia de M. maximus

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.

Genetic potential for an acute inflammatory response in IgA glomerulonephritis in mice

Mice selected on the basis of an acute inflammatory response (AIR) can provide information about the immunopathological mechanisms of glomerulonephritis. We studied the differences between mice selected for a maximal AIR (AIRmax that attract more polymorphonuclear cells to the site of injury) or a minimal AIR (AIRmin that attract more mononuclear cells) in an experimental model of IgA nephropathy in order to investigate the effect of genetic background on glomerular disease progression and the participation of the monocyte chemoattractant protein-1 (MCP-1) chemokine. IgA nephropathy was induced by intraperitoneal ovalbumin injection and bile duct ligation in AIRmax and AIRmin mice. Histological changes, urinary protein/creatinine ratio, serum IgA levels, immunofluorescence for IgA, IgG and complement C3 fraction, immunohistochemistry for macrophages and MCP-1, and MCP-1 levels in macerated kidney were determined. Mesangial IgA deposition was seen only in AIRmin mice, which presented more renal lesions. Increased serum IgA levels (1.5 ± 0.4 vs 0.3 ± 0.1 mg/mL, P < 0.001), high glomerular MCP-1 expression and decreased monocyte/macrophage infiltration in the interstitial area (0.3 ± 0.3 vs 1.1 ± 0.9 macrophages/field, P < 0.05) were detected in AIRmin mice compared to AIRmax mice. No glomerular monocyte/macrophage infiltration was detected in either strain. In spite of the absence of IgA deposition, AIRmax mice presented discrete or absent mesangial proliferation. The study showed that there are differences between mice selected for AIRmax and AIRmin with respect to serum IgA levels, histological damage and MCP-1 chemokine production after ovalbumin injection in combination with bile duct ligation.

Prazosin blocks the glutamatergic effects of N-methyl-D-aspartic acid on lordosis behavior and luteinizing hormone secretion in the estrogen-primed female rat

We have observed that intracerebroventricular (icv) injection of selective N-methyl-D-aspartic acid (NMDA)-type glutamatergic receptor antagonists inhibits lordosis in ovariectomized (OVX), estrogen-primed rats receiving progesterone or luteinizing hormone-releasing hormone (LHRH). When NMDA was injected into OVX estrogen-primed rats, it induced a significant increase in lordosis. The interaction between LHRH and glutamate was previously explored by us and another groups. The noradrenergic systems have a functional role in the regulation of LHRH release. The purpose of the present study was to explore the interaction between glutamatergic and noradrenergic transmission. The action of prazosin, an alpha1- and alpha2b-noradrenergic antagonist, was studied here by injecting it icv (1.75 and 3.5 µg/6 µL) prior to NMDA administration (1 µg/2 µL) in OVX estrogen-primed Sprague-Dawley rats (240-270 g). Rats manually restrained were injected over a period of 2 min, and tested 1.5 h later. The enhancing effect induced by NMDA on the lordosis/mount ratio at high doses (67.06 ± 3.28, N = 28) when compared to saline controls (6 and 2 µL, 16.59 ± 3.20, N = 27) was abolished by prazosin administration (17.04 ± 5.52, N = 17, and 9.33 ± 3.21, N = 20, P < 0.001 for both doses). Plasma LH levels decreased significantly only with the higher dose of prazosin (1.99 ± 0.24 ng/mL, N = 18, compared to saline-NMDA effect, 5.96 ± 2.01 ng/mL, N = 13, P < 0.05). Behavioral effects seem to be more sensitive to the alpha-blockade than hormonal effects. These findings strongly suggest that the facilitatory effects of NMDA on both lordosis and LH secretion in this model are mediated by alpha-noradrenergic transmission.

Human prophylactic vaccine adjuvants and their determinant role in new vaccine formulations

Adjuvants have been considered for a long time to be an accessory and empirical component of vaccine formulations. However, accumulating evidence of their crucial role in initiating and directing the immune response has increased our awareness of the importance of adjuvant research in the past decade. Nevertheless, the importance of adjuvants still is not fully realized by many researchers working in the vaccine field, who are involved mostly in the search for better target antigens. The choice of a proper adjuvant can be determinant for obtaining the best results for a given vaccine candidate, but it is restricted due to intellectual property and know-how issues. Consequently, in most cases the selected adjuvant continues to be the aluminum salt, which has a record of safety, but predominantly constitutes a delivery system (DS). Ideally, new strategies should combine immune potentiators (IP) and DS by mixing both compounds or by obtaining structures that contain both IP and DS. In addition, the term immune polarizer has been introduced as an essential concept in the vaccine design strategies. Here, we review the theme, with emphasis on the discussion of the few licensed new adjuvants, the need for safe mucosal adjuvants and the adjuvant/immunopotentiating activity of conjugation. A summary of toxicology and regulatory issues will also be discussed, and the Finlay Adjuvant Platform is briefly summarized.

Effect of huitlacoche (Ustilago maydis DC Corda) paste addition on functional, chemical and textural properties of tortilla chips

AbstractThis study analyzed the addition of huitlacoche paste (HP) in baked tortilla chips (TC), evaluating its effects on functional, physicochemical and structural changes during processing. Two blue corn grains were nixtamalized, stone milled, air dried and milled to obtain flour; commercial blue corn flour (TM1) and commercial TC (TM2) were used as controls. Additions of 0, 3, 6 and 9% of HP were formulated; masas were prepared at 55% moisture content (MC), precooked and baked in an industrial machine. TC crispiness was influenced by grain characteristics and percentage of HP. Huitlacoche paste addition caused an increase in total dietary fiber (from 5.27 to 14.54%), total soluble phenolics content (from 17.52 to 37.60 mg GAE/100 g) and antioxidant capacity (from 6.74 to 7.98 μmol TE/g) in TC. Results suggest that tortilla chips added with huitlacoche can be an alternative to prepare this traditional edible fungus and produce healthier snacks, not fried and enriched with bioactive compounds.

Testes do pH do exsudato para sementes de milho

Com a finalidade de verificar os resultados para genótipos de milho e simplificar o processo por meio da avaliação individual e massal das sementes, desenvolveu-se o presente estudo. Foram utilizados 32 lotes de sementes de milho em dois experimentos. O primeiro visou a avaliação individual do pH do exsudato das sementes, empregando concentrações de uma solução indicadora (SI) composta de carbonato de sódio e fenolftaleína, e períodos de embebição de sementes. O segundo visou a avaliação massal das sementes em duas modalidades: (i) do tempo necessário até desaparecimento da coloração rosa forte do meio contendo sementes, água destilada e SI agregada ao início da prova, (ii) quantidade da SI necessária para colorir o exsudato das sementes após embebição em água destilada. A germinação e o vigor (teste de frio) foram correlacionados com os dados obtidos no teste de pH do exsudato. Baseado nos resultados concluiu-se que é possível determinar a viabilidade das sementes pelo teste de pH do exsudato massal, porém, apresenta relação mediana com o teste de frio. O processo de determinação da viabilidade das sementes pelo teste de pH do exsudato individual que melhor relaciona-se é o utilizado a SI após 20' de embebição. Na avaliação massal, é possível determinar que lotes de sementes de baixa qualidade requerem mais de 0,7ml da SI para mudar de coloração, após 25min. de embebição.