Epigallocatechin-3-gallate local pre-exposure application prevents SHIV rectal infection of macaques.

Epigallocatechin-3-gallate (EGCG), a natural and major ingredient of green tea, has been shown to have anti-inflammation and anti-HIV-1 properties. We demonstrated that the intrarectal administration of EGCG could protect rhesus macaques from repetitive, intrarectal challenges with low-dose SHIVSF162P3N. This protection has a per-exposure risk reduction of 91.5% (P = 0.0009; log-rank test) and a complete protection of 87.5% (P < 0.001; Fisher's exact test). All protected animals showed no evidence of systemic and mucosal SHIV infection as demonstrated by the absence of viral RNA, DNA and antibodies. In contrast, all controls became infected after repeated SHIV challenges (a median of 2.5 times, range of 1-8 times). Mechanistically, EGCG could block the binding of HIV-1 gp120 to CD4 receptor and suppress the macrophage infiltration/activation in the rectal mucosa of macaques. These data support further clinical evaluation and development of EGCG as a novel, safe and cost-effective microbicide for preventing sexual transmission of HIV-1.

Neurotoxic effects of interleukin-6 and sodium nitroprusside on cultured rat hippocampal neurons.

The neurotoxicity of interleukin-6 (IL-6) and sodium nitroprusside (SNP, CAS 13755-38-9) was examined using primary cultures of rat hippocampal neurons. The cell viability was significantly reduced after the cultures were co-incubated with IL-6 4, 40, 400 ng/ml or SNP 1, 10, 100 mumol/l for 24 h. In addition, N omega-nitro-L-arginine (NNA, CAS 2149-70-4) at 0.1 mmol/l, when co-added with IL-6 400 ng/ml in cultures, significantly increased IL-6 reduced viability from 78.3 +/- 6.7% to 113.3 +/- 10.0%. These results indicate that IL-6 exerts neurotoxicity on cultured hippocampal neurons probably via overformation of nitric oxide in cultures.

Effects of intrahippocampal infusion of interleukin-6 on passive avoidance and nitrite and prostaglandin levels in the hippocampus in rats.

Bilateral infusion of interleukin-6 (IL-6) 80 ng into the hippocampus has been shown to impair retention of a step-through passive avoidance task via shortening the step-through latency in testing. This infusion with IL-6 also increased the levels of nitrite and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in rat hippocampus. In addition, intraperitoneal injection of NG-nitro-L-arginine (CAS 2149-70-4) 100 mg/kg for 5 days improved the retention impairment induced by IL-6 and meanwhile antagonized the increase in nitrite levels. Furthermore, intraperitoneal injection with indometacin (CAS 53-86-1) 10 mg/kg daily for 5 days reduced the IL-6-induced increase in 6-keto-PGF1 alpha levels. These results indicate that IL-6 impairs retention of passive avoidance probably via the overproduction of nitric oxide (NO) and suggest that IL-6 may possess an inducible effect on NO synthase and cyclo-oxygenase in the hippocampus. These findings support the hypothesis that central IL-6 participates in the pathogenesis of Alzheimer's disease, and the overproduction of nitric oxide in the brain may partially mediate the amnesic effect of IL-6.

A escuta do discurso instrucional: recurso na formação docente

O processo de formação docente deve incluir atividades que desenvolvam as competências do professor para perceber, compreender e avaliar a linguagem da sala de aula. Por isso, esse trabalho objetivou estruturar um procedimento de escuta de registros audiogravados de episódios de ensino a partir dos quais são descritas possibilidades de mediação pedagógica. Vários episódios são discutidos ilustrando como este material subsidia a atividade prático-reflexiva de alfabetizadores e agentes de formação, evidenciando competências e necessidades de desenvolvimento profissional (AU)

Suppression of lipopolysaccharide-induced impairment of active avoidance and interleukin-6-induced increase of prostaglandin E2 release in rats by indometacin.

The effects of indometacin (CAS 53-86-1) on lipopolysaccharide-induced impairment of active avoidance and on interleukin-6-induced increase of prostaglandin E2 release were investigated in rats. In the experiment on acquisition and retention of one-way active avoidance in a shuttle box model, bilateral infusion of lipopolysaccharides (LPS) into the hippocampus, 1 microgram per side, resulted in a significant impairment both in acquisition and retention by prolonging the latency of avoidance in training and testing. In the meantime, intraperitoneal injection of indometacin 10 mg/kg daily for 7 days, improved the LPS-induced amnesia especially in the testing by shortening the latency from 2.3 to 1.7 s (p < 0.05). In the in vivo microdialysis study in anesthetized rats, intrahippocampal infusion of 80 ng interleukin-6 (IL-6) markedly increased prostaglandin E2 (PGE2) release into hippocampal dialysates which started at 2 h post administration. Perfusion of indometacin (0.3 mol/l) into the hippocampus for 1 h obviously suppressed the IL-6-induced PGE2 response. These findings provide experimental evidence that--assuming that central inflammation may be involved with Alzheimer's disease a non-steroidal anti-inflammatory drug may be used in the treatment of Alzheimer's disease.

Intrahippocampal infusion of interleukin-6 impairs avoidance learning in rats.

AIM: To study the effect of intrahippocampal infusion of interleukin-6 (IL-6) on active avoidance in rats and the possible involvement of nitric oxide (NO). METHODS: Using a shuttle-box model, the effects of bilaterally intrahippocampal infusion of IL-6 3.2, 16, and 80 ng as well as sodium nitroprusside (SNP) 400 ng on active avoidance were studied on d 8 after administration. The levels of nitrite as an index of NO in the hippocampus were detected using a fluorometric assay 24 h after infusion of IL-6 3.2 or 80 ng. RESULTS: IL-6 16 and 80 ng impaired the acquisition performance of active avoidance by prolonging the latency of avoidance in training, but not the retention performance in testing. IL-680 ng and SNP 400 ng also resulted in a marked impairment in acquisition performances by decreasing the rate of avoidance, but not in retention performances. IL-680 ng markedly elevated the nitrite levels from 10.6 +/- 0.7 in control rats to 13.6 +/- 2.0 (nmol/g wet wt) (P < 0.01). IL-6 3.2 ng had no effect on active avoidance nor on nitrite levels. CONCLUSION: Intrahippocampal infusion of IL-6 impaired learning acquisition of active avoidance in rats.

Effect of 20(S)-ginsenoside-Rg2 and cyproheptadine on two-way active avoidance learning and memory in rats.

The effects of 20(S)-ginsenoside-Rg2 (GRg2, CAS 52286-74-5) and cyproheptadine (CYP, CAS 129-03-3) on acquisition, retention and retrieval were examined in male Wistar rats using a two-way active avoidance method. Learning and memory were estimated by the avoidance rate (%) and/or latency (s). Acute administration of CYP 1.0 mg/kg i.p. 30 min prior to training produced a significant impairment in acquisition of 3 d learning and 48 h memory by decreasing the rate from 87.9 +/- 2.1, 75.8 +/- 4.9 in saline rats to 55.8 +/- 9.6, 53.4 +/- 8.4, respectively (F(1,14) = 10.7, 14.8, p < 0.01). The CYP administration immediately following the end of training and 30 min before testing produced the impairments in retention of 24 h memory and in retrieval of 48 h memory by decreasing the rate from 86.7 +/- 1.7, 93.3 +/- 2.7 to 55.0 +/- 5.5, 60.0 +/- 6.8, respectively (F(1,12) = 27.2, 10.5, p < 0.01). Repeated administration of GRg2 20 mg/kg i.p. significantly improved the CYP-induced recognitional deficits by increasing the CYP-decreased rate from 55.8 +/- 9.6 to 80.8 +/- 4.2 in d 3 learning acquisition (F(1,14) = 5.6, p < 0.05), from 53.4 +/- 8.4 to 60.0 +/- 8.2 in 48 h memory acquisition (F(1,14) = 7.5, p < 0.05) and from 55.0 +/- 5.5 to 88.3 +/- 2.5 in 24 h memory retention (F(1,12) 27.5, p < 0.01) as well as from 60.0 +/- 6.8 to 85.6 +/- 6.9 in 48 h memory retrieval (F(1,12) = 5.2, p < 0.05), respectively. The results also provide the suggestive evidence that central serotonin may play a positive modulatory role in the acquisition, retention and retrieval of two-way active avoidance responding in rats.

Effects of ginseng stem-leaves saponins on one-way avoidance behavior in rats.

Using a multiple-trial, training-to-criterion procedure, the effects of repeated administrations of ginseng stem-leaves saponins (GSLS) on learning and memory of one-way avoidance in rats were studied in shuttle-box. In acquisition, GSLS 10, 30, and 60 mg.kg-1 ip shortened the latency of avoidance in a bell-shaped manner from 1.0 +/- 0.2 s in saline rats to 0.8 +/- 0.5, 0.5 +/- 0.1, 0.8 +/- 0.2 s (d 3 learning) and from 0.9 +/- 0.2 s to 0.8 +/- 0.2, 0.7 +/- 0.1, and 0.8 +/- 0.2 s (10 x 24 h memory), and the best dose was 30 mg.kg-1. GSLS 30 mg.kg-1 ip shortened the latency of avoidance prolonged by scopolamine 0.8 mg.kg-1 sc from 5.2 +/- 1.3 s to 3.9 +/- 0.8 s (d 1 learning acquisition) and from 2.2 +/- 0.6 s to 0.8 +/- 0.3 s (3 x 24 h memory acquisition). In retention, GSLS 30 mg.kg-1 ip shortened the latency prolonged by cycloheximide 2.5 and 5 mg.kg-1 ip from 3.4 +/- 1.0 s to 1.4 +/- 0.5 s (4 h memory) and from 1.6 +/- 0.3 s to 0.9 +/- 0.2 s (24 h memory), and increased the avoidance number decreased by cycloheximide 5 mg.kg-1 from 38.1 +/- 8.8% to 72.4 +/- 10.8% (4 h memory). The results indicate that GSLS facilitated the acquisition of learning and memory in rats, and improved the scopolamine amnesia and cycloheximide amnesia.