Management of defoliation in Trifolium vesiculosum S. for the production of seeds / [Manejo da desfolha em Trifolium vesiculosum Savi para a produção de sementes]

The present study aims to determine the appropriate defoliation management for the production of seeds and forage in arrowleaf clover via trail analysis. The results obtained demonstrated that defoliation practices have a great influence on the composition of seed yield and germination power. In addition, when the goal is the maximum balance between dry matter production and seed yield, this can be achieved in up to two defoliation practices. These results are confirmed by analyzing the positive association between the weight of a thousand seeds and the seed yield. When the third defoliation practice is performed, it negatively correlates with the weight of a thousand seeds, suggesting that, with the increase in defoliation frequency, there is a lower weight of a thousand seeds, and, therefore, lower seed yield. Therefore, management planning in Trifolium vesiculosum Savi that aims at natural reseeding, maximum yield and seed germination must prioritize one to two defoliation practices, aiming to promote favorable conditions for the perennialization of the species. In this context, the trail analysis proved to be a useful tool as a criterion for obtaining the ideal management aiming at the production of seeds and forage in vesicular clover.(AU)

O presente estudo visa determinar o manejo de desfolha adequado para a produção de sementes e de forragem em trevo-vesiculoso via análise de trilha. Os resultados obtidos demonstraram que as práticas de desfolha possuem grande influência na composição do rendimento de sementes e no poder germinativo. Além disso, quando o objetivo for o máximo equilíbrio entre a produção de matéria seca e o rendimento de sementes, esse pode ser alcançado em até duas práticas de desfolha. Esses resultados são confirmados ao se analisar a associação positiva entre o peso de mil sementes e o rendimento de sementes. Quando realizada a terceira prática de desfolha, esta se correlaciona negativamente com o peso de mil sementes, sugerindo que, com o aumento da frequência de desfolha, ocorre menor peso de mil sementes e, por conseguinte, menor rendimento de sementes. Portanto, o planejamento do manejo em T. vesiculosum Savi que objetive a ressemeadura natural, o máximo rendimento e a germinação de sementes deve priorizar até duas práticas de desfolha, visando promover condições favoráveis para a perenização da espécie. Nesse contexto, a análise de trilha demonstrou ser uma ferramenta útil como critério para obtenção do manejo ideal visando à produção de sementes e de forragem em trevo-vesiculoso.(AU)

Pharmacological approaches to induce follicular growth and ovulation for fixed-time artificial insemination treatment regimens in ewes.

In Experiment I, during the non-breeding season, after intravaginal devices containing progesterone (P4) were withdrawn (n = 28), estrous rates were greater with treatment with 400 IU eCG (P < 0.05) than with FSH (10 and 15 mg) and no treatment. During the breeding season (n = 147), estrous and pregnancy rates after fixed-time artificial inseminations (FTAI) were similar among groups: 300 IU eCG; 10 mg FSH; and control (P > 0.05). In Experiment II (non-breeding season), ewes of one group were treated with 300 IU eCG (n = 8) and of two groups were treated with 10 mg FSH. In one FSH group, 250 µg estradiol benzoate (EB) were administered after 24 h (n = 9); in the other, 4 µg GnRH were administered after 36 h (n = 10). Serum P4 concentrations were greater in eCG-treated ewes (P < 0.05). Estrous rates were similar for the eCG- and FSH plus EB-treated ewes (P > 0.05). In Experiment III (breeding season), the treatments were: 300 IU eCG; 250 µg estradiol cypionate; 250 µg EB; or control (n = 22). Follicular growth was greater for eCG-treated ewes within 0-24 h and for control ewes within 48-72 h (P = 0.001). Although estrous and ovulation rates did not differ (P > 0.05), all eCG-treated ewes had ovulations. During the non-breeding season, FSH treatment promoted follicular growth but did not induce ovulations. For FTAI regimens, eCG was more effective than FSH plus GnRH and estradiol esters in inducing estrus and ovulation.

Beneficial effects of enriched environment following status epilepticus in immature rats.

BACKGROUND: There is increasing evidence that enriching the environment can improve cognitive and motor deficits following a variety of brain injuries. Whether environmental enrichment can improve cognitive impairment following status epilepticus (SE) is not known. OBJECTIVE: To determine whether the environment in which animals are raised influences cognitive function in normal rats and rats subjected to SE. METHODS: Rats (n = 100) underwent lithium-pilocarpine-induced SE at postnatal (P) day 20 and were then placed in either an enriched environment consisting of a large play area with toys, climbing objects, and music, or in standard vivarium cages for 30 days. Control rats (n = 32) were handled similarly to the SE rats but received saline injections instead of lithium-pilocarpine. Rats were then tested in the water maze, a measure of visual-spatial memory. A subset of the rats were killed during exposure to the enriched or nonenriched environment and the brains examined for dentate granule cell neurogenesis using bromodeoxyuridine (BrdU) and phosphorylated cyclic AMP response element binding protein (pCREB) immunostaining, a brain transcription factor important in long-term memory. RESULTS: Both control and SE rats exposed to the enriched environment performed significantly better than the nonenriched group in the water maze. There was a significant increase in neurogenesis and pCREB immunostaining in the dentate gyrus in both control and SE animals exposed to the enriched environment compared to the nonenriched groups. Environmental enrichment resulted in no change in SE-induced histologic damage. CONCLUSIONS: Exposure to an enriched environment in weanling rats significantly improves visual-spatial learning. Even following SE, an enriched environment enhances cognitive function. An increase in neurogenesis and activation of transcription factors may contribute to this enhanced visual-spatial memory.

Timing of cognitive deficits following neonatal seizures: relationship to histological changes in the hippocampus.

Neonatal seizures are frequently associated with cognitive impairment and reduced seizure threshold. Previous studies in our laboratory have demonstrated that rats with recurrent neonatal seizures have impaired learning, lower seizure thresholds, and sprouting of mossy fibers in CA3 and the supragranular region of the dentate gyrus in the hippocampus when studied as adults. The goal of this study was to determine the age of onset of cognitive dysfunction and alterations in seizure susceptibility in rats subjected to recurrent neonatal seizures and the relation of this cognitive impairment to mossy fiber sprouting and expression of glutamate receptors. Starting at postnatal day (P) 0, rats were exposed to 45 flurothyl-induced seizures over a 9-day period of time. Visual-spatial learning in the water maze and seizure susceptibility were assessed in subsets of the rats at P20 or P35. Brains were evaluated for cell loss, mossy fiber distribution, and AMPA (GluR1) and NMDA (NMDAR1) subreceptor expression at these same time points. Rats with neonatal seizures showed significant impairment in the performance of the water maze and increased seizure susceptibility at both P20 and P35. Sprouting of mossy fibers into the CA3 and supragranular region of the dentate gyrus was seen at both P20 and P35. GluR1 expression was increased in CA3 at P20 and NMDAR1 was increased in expression in CA3 and the supragranular region of the dentate gyrus at P35. Our findings indicate that altered seizure susceptibility and cognitive impairment occurs prior to weaning following a series of neonatal seizures. Furthermore, these alterations in cognition and seizure susceptibility are paralleled by sprouting of mossy fibers and increased expression of glutamate receptors. To be effective, our results suggest that strategies to alter the adverse outcome following neonatal seizures will have to be initiated during, or shortly following, the seizures.

Interictal hyposexuality in male patients with epilepsy.

The purpose of this study was to compare the serum levels of androgens between hyposexual and non-hyposexual patients with epilepsy. Adult male patients with epilepsy were investigated. Serum levels of testosterone (T) and free-T, estradiol, and sex hormone binding globulin (SHBG) were measured and the free androgen index (FAI) was calculated. While there were no differences between hyposexual and non-hyposexual patients in the serum levels of T, free-T, and estradiol, or to the FAI, the serum levels of SHBG were significantly higher in hyposexual patients than in non-hyposexual patients. Thus, the effects of increased SHBG upon serum levels of testosterone biologically active in patients with epilepsy and hyposexuality were not detected by the methods used in this study. Four (44%) of nine hyposexual patients who were re-evaluated after two years follow-up improved sexual performance. Thus, clinical treatment that results in good seizure control may improve sexual performance in some patients with epilepsy.

Flurothyl-induced seizures in rats activate Fos in brainstem catecholaminergic neurons.

Autonomic changes accompany seizures in both animals and humans. While ictal autonomic dysfunction can be life-threatening, the participating neural networks involved are poorly understood. In this study we examined the activation of Fos following generalized seizures in brainstem structures known to mediate autonomic function. Adult female rats were sacrificed 2 h after flurothyl-induced seizures. Double-immunostaining for c-Fos and dopamine-beta-hydroxylase (DBH), and c-Fos and phenylethanol-N-methyl-transferase (PNMT) were performed in brainstem slices. Numbers of DBH-labeled neurons expressing Fos-like immunoreactivity (FLI) (DBH/Fos) and PNMT labeled neurons expressing FLI (PNMT/Fos) were counted in the noradrenergic (A1, A2, A5, A7) and adrenergic (C1, C2) cell groups localized in pons and medulla oblongata. Among the experimental animals, the highest degree of co-localization of DBH/Fos neurons was observed in the locus coeruleus (A6; 87.7%), and in the A1(72.8%) cell group located in the caudal ventrolateral medulla (VLM). No co-localization of DBH/Fos neurons was observed in control animals. The highest degree of co-localization of PNMT/Fos neurons was observed in the C1 adrenergic cell group (84.2%) located in the rostral VLM. Control animals showed very few (5.5%) PNMT/Fos co-localized neurons in the C1 adrenergic cell group. Our results indicate that flurothyl-induced generalized seizures in rats activate catecholaminergic neurons in the pons and medulla oblongata. Further studies are necessary to determine whether activation of brainstem catecholaminergic neurons contribute to the autonomic manifestations that frequently accompany epileptic seizures.

Consequences of recurrent seizures during early brain development.

It is well documented that prolonged seizures (status epilepticus) can cause neuronal injury and result in synaptic reorganization in certain brain regions. However, the effect of recurrent, relatively short seizures in young animals on subsequent brain development is not known. To study the consequences of recurrent seizures on the developing brain, we subjected immature rats to a total of 50 flurothyl-induced seizures from postnatal day 11 until day 23. Immunohistochemistry for c-fos was performed to characterize the pattern of neuronal activation following the seizures. Cell counting of dentate granule cells, CA3, CA1, and hilar neurons, using unbiased stereological methods, and the silver impregnation method were used to evaluate neuronal death following the recurrent seizures. Timm and Golgi staining were performed four weeks after the 50th seizure to evaluate the effects of recurrent seizures on synaptic organization. Our results show that recurrent flurothyl-induced seizures progressively increased excitability of the brain, as revealed by a dramatic increase in the extent and intensity of c-fos immunostaining. While no cell loss was detected in the hippocampus with either Cresyl Violet or silver stains, animals experiencing multiple daily seizures developed increased mossy fiber sprouting in both the supragranular layer of the dentate gyrus and the infrapyramidale layer of the CA3 region. Golgi staining confirmed that there was an increase in mossy fibers in the pyramidal cell layer. Our results suggest that serial recurrent seizures in the immature brain can lead to significant changes in mossy fiber distribution even though the seizures do not cause significant hippocampal cell loss.

Acoustic brainstem nuclei express Fos after flurothyl-induced generalized seizures in rats.

The inferior colliculus (IC) plays a key role in modulating audiogenic seizures (AS) in rats. We investigated whether acoustic brainstem nuclei express Fos-like immunoreactivity (FLI) after flurothyl-induced generalized seizures in rats. Compared to controls, experimental animals showed significantly (P<0.05) more FLI in the dorsal and external cortex of the IC, as well as in the medial part of the medial geniculate body (MGB), perigeniculate area, and dorsal cochlear nucleus. No significant increase of FLI was observed in the central nucleus of the IC, ventral and dorsal parts of the MGB, dorsal nucleus of the lateral lemniscus, or ventral cochlear nucleus. Because this pattern of FLI closely resembles that observed after AS in previous studies, these results suggest that Fos expression in acoustic brainstem nuclei is not specific for AS.

Activation of the locus coeruleus after amygdaloid kindling.

PURPOSE: Substantia nigra (SN) and locus coeruleus (LC) neurons are implicated in the propagation and suppression of amygdaloid seizures. Both structures are activated concomitant with amygdaloid seizure discharges. Their mechanisms of activation, however, remain to be elucidated. SN firing is not associated with the induction of Fos immunoreactivity (ir), a marker of excitatory neuronal activation. LC has not been studied. The purpose of this investigation was to determine if amygdala-kindled generalized seizures could induce Fos-ir in the LC. METHODS: Female Sprague-Dawley rats were killed after generalized seizures induced by amygdala electrical stimulation and stained by using Fos immunocytochemistry. The number of Fos-ir neurons was compared between 15 animals with generalized seizures and four implanted, unstimulated controls. RESULTS: LC-ir neurons were significantly (p < 0.05) more prevalent after seizures than in control animals. Their numbers correlated very highly with Fos-ir in the central nucleus of the amygdala (p < 0.0001). No Fos induction was observed in LC in controls or in the SN in either group. CONCLUSIONS: Amygdala-induced generalized seizures result in Fos-ir in the LC but not in the SN. This is consistent with different mechanisms of activation possibly involving disinhibition in the SN and direct excitation in the LC.

Seizures in rats treated with kainic acid induce Fos-like immunoreactivity in locus coeruleus.

Kainic acid-triggered seizures (KATS) induce Fos-like immunoreactivity (FLI) in limbic structures, which send efferents to the locus coeruleus (LC). Following KATS, brain stem sections were stained for Fos immunocytochemistry and double immunostained for Fos and dopamine beta-hydroxylase (DBH). KA-treated animals showed significantly greater numbers of FLI neurons in the LC than control animals (p < 0.05). Co-localization of DBH/Fos was observed in 89.7% of the LC neurons in KA-treated animals and in 1.4% of LC neurons in control animals. Thus, KATS heavily induce Fos in DBH-containing neurons in the LC, which are known to project to the hippocampus. However, the role of activation of the LC noradrenergic neurons during KATS is not well understood at this present time.

Epilepsias recém-diagnosticadas: aderência, tolerância e prognóstico com a primeira droga / Recently diagnosed epilepsy: adherence, tolerance, and prognostic with the first drug

Há poucos dados no nosso meio sobre epilepsias recém-diagnosticadas (ERD). Com o objetivo de avaliar a aderência, a tolerância e a eficácia da primeira droga antiepiléptica receitada, seguimos 78 pacientes de 6 a 61 anos de idade (média: 17.96 anos) com ERD por um tempo médio de 12.68 meses (1 a 29 meses). Estes pacientes apresentavam crises parciais, com ou sem generalizaçäo secundária, e crises generalizadas tônico-clônicas com um tempo médio de epilepsia de 7.68 meses (4 dias a 7 anos). Encontramos 11 pacientes (14.10 por cento ) näo aderentes ao tratamento e 14 (17,94 por cento ) com efeitos colaterais que justificaram a troca da medicaçäo. Os efeitos colaterais mais prevalentes foram alteraçöes dismórficas como hirsutismo e hiperplasia gengival, síndrome dispéptica, reaçöes idiossincrásicas e sedaçäo. Sessenta e seis por cento dos pacientes mantiveram-se completamente controlados por um período de 8 semanas e 63.88 por cento por 56 semanas. Estes dados säo consistentes com os achados da literatura internacional. A taxa de näo aderência ao tratamento foi relativamente alta (14,10 por cento ), possivelmente devido aos aspectos sócio-econômicos e culturais da populaçäo estudada. Ressaltamos que 17,94 por cento dos pacientes näo toleraram a primeira droga, necessitando de substituiçäo. Aproximadamente 2/3 dos pacientes com ERD obtém controle satisfatório com a primeira medicaçäo