Asymmetric Total Synthesis of Brasiliquinones B and C via Oxidative Cyclization of a Hydroquinone-Silyl Enol Ether Hybrid.

The asymmetric total synthesis of angucycline antibiotics (S)-brasiliquinones B and C was accomplished. The benz[a]anthraquinone core was constructed via oxidative cyclization of a hydroquinone-silyl enol ether hybrid. The resultant pentacyclic acetal was converted to the silyl enol ether, which was treated with Pd(II)/O2 to afford brasiliquinone C, after multistep conversion including dehydrogenation, desilylation and deacetalization, and hydroquinone oxidation. The (S)-configuration of natural brasiliquinones was confirmed based on the stereochemical correlation with the synthetic products.

An insight on acyl migration in solvent-free ethanolysis of model triglycerides using Novozym 435.

In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20mg), reaction time (30-90min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase.

Biodiesel from uncommon fatty acids.

Ethyl esters from uncommon fatty acids, such as valproic, azelaic, and sorbic acids, were chemically synthesized and identified by gas chromatography or liquid chromatography coupled to mass spectrometry. Some properties were evaluated to determine their potential for use as biofuels or in other commercial applications. They have remarkable and pleasant odors and, in the case of ethyl ester in valproic acid, display marked resistance to clouding and crystallization.

Reproducibility of sterilized rubber impressions.

Impressions, dentures and other dental appliances may be contaminated with oral micro-flora or other organisms of varying pathogenicity from patient's saliva and blood. Several approaches have been tried to control the transmission of infectious organisms via dental impressions and because disinfection is less effective and has several drawbacks for impression characterization, several sterilization methods have been suggested. This study evaluated the reproducibility of rubber impressions after sterilization by different methods. Dimensional accuracy and wettability of two rubber impression materials (vinyl polysiloxane and polyether) were evaluated after sterilization by each of three well-known methods (immersion in 2% glutaraldehyde for 10 h, autoclaving and microwave radiation). Non-sterilized impressions served as control. The effect of the tray material on impression accuracy and the effect of topical surfactant on the wettability were also evaluated. One-way ANOVA with Dunnett's method was used for statistical analysis. All sterilizing methods reduced the reproducibility of rubber impressions, although not always significantly. Microwave sterilization had a small effect on both accuracy and wettability. The greater effects of the other methods could usually be overcome by using ceramic trays and by spraying impression surfaces with surfactant before pouring the gypsum mix. There was one exception: glutaraldehyde still degraded dimensional accuracy even with ceramic trays and surfactant. We conclude that a) sterilization of rubber impressions made on acrylic trays was usually associated with a degree of dimensional change; b) microwave energy seems to be a suitable technique for sterilizing rubber impressions; c) topical surfactant application helped restore wettability of sterilized impressions.

Propriedades da anestesia inalatória com éter sulfúrico em ratos / Properties of the inhalatory anesthesia with sulfuric ether in rats

O éter etílico em cirurgia experimental, continua a ser utilizado, principalmente por apresentar baixo custo e fácil manuseio. No entanto, o controle rigoroso de sua comercializaçäo pela Polícia Federal, dificultou sosbremaneira sua aquisição. Desta maneira, o objetivo do presente é estudar as propriedades da anestesia inalatória com éter sulfúrico em ratos. Foram utilizados 20 Ratus norvegicus albinus, machos, adultos, pesando em média 278,6g. Distribuídos em dois grupos: Grupo Éter Sulfúrico (GS7)(n=10) e Grupo Éter Sulfúrico (GS14)(n=10), cujos animais receberam éter sulfúrico inalatório, por 45 minutos diários, durante 7 e 14 dias consecutivos, respectivamente. A anestesia inalatória foi dividida em três períodos: indução, manutenção e recuperação pós-anestésica. Durante a anestesia foram monitorados a frequência respiratória, volume total de éter consumido, tempo de recuperação e presença de intercorrências. A freqüência respiratória e o tempo de recuperação não sofreram modificação estatisticamente significante da 1ª para 2ª semana do experimento, enquanto que o volume total de éter consumido foi significamente maior na 2ª em relação a 1ª semana do estudo. Houve um aumento da dificuldade de manutenção anestésica e uma diminuição da secreção traqueo-brônquica, significantes, da 1ª para 2ª semana. A anestesia inalatória com éter sulfúrico manteve a FR no limiar de 100 ipm, não causou óbito, demonstrou segurança a facilidade de manuseio da droga e um possível mecanismo de tolerância, induzindo pelo uso prolongado do éter sulfúrico por via inalatória, em ratos

Efeito de cálculos biliares humanos na cavidade peritoneal de ratos / Effects of human gallstones on the peritoneal cavity of rats

Este estudo tem por objetivo analisar experimentalmente as características macroscópicas e microscópicas de cálculos biliares humanos na cavidade peritoneal de ratos. Foram utilizados 32 ratos Wistar, machos, pesando entre 205 e 268 g. Estes animais foram distribuídos em dois grupos e o procedimento cirúrgico foi realizado em cada grupo: no grupo A (n=16), os animais foram submetidos a manipulaçao intestinal; no grupo B (n=16), cálculos biliares humanos foram colocados na cavidade peritoneal. Os ratos foram avaliados no 21º e 42º dias do período pós-operatório. Os resultados mostraram que a simples manipulaçao causou aderências no animais (n=10). As aderências foram notadas em 11 cálculos no grupo B. Histologicamente nao houve fibrose intensa em torno do cálculo, principalmente no 42º dia do período pós-operatório. Nao foram observados macro ou micro abscessos e nao houve evidências de fluído livre intra-peritoneal. Este estudo demonstra que apesar da baixa incidência de complicaçoes, todas as tentativas devem ser feitas para recuperar cálculos perdidos durante colecistectomia.

Alteraçöes histopatológicas em ratos anestesiados com éter sulfúrico / Hystopathological alterations in rats anesthetized with sulfuric ether

O rato é o animal preferencialmente utilizado, tanto no âmbito anestésico como no cirúrgico experimental. Neste animal várias drogas e técnicas anestésicas têm sido utilizadas, dentre elas o éter por via inalatória, com uso de câmaras de induçäo e de vaporizadores de fluxo contínuo. Desta forma, o objetivo deste trabalho foi estudar a estrutura histológica de órgäos de ratos anestesiados com éter sulfúrico por via inalatória. Foram utilizados 24 Rattus norvegicus albinus, machos, adultos, pesando 285 (+/-20) gramas, com 120 a 150 dias de vida, distribuídos em dois grupos: Grupo A (n=12), no qual foi utilizado éter sulfúrico como agente anestésico inalatório, e Grupo C, grupo controle (n=12), em cujos animais näo foi realizado nenhum anestésico, sendo submetidos à eutanásia com injeçäo de 5 ml de cloreto de potássio a 10 por cento por via intra-peritonial. O grupo A foi dividido em 3 subgrupos: A1 (n=4), A7 (n=4) e A15 (n=4), cujos animais receberam anestesia por 30 minutos diários durante, um, sete e quinze dias consecutivos. Completado o ciclo anestésico de cada subgrupo, os animais foram submetidos à eutanásia com dose inalatória letal de éter sulfúrico, sendo retiradas vísceras (cérebro, fígado, pulmäo, rim e traquéia), para análise macroscópica e estudo histopatológico. Dentre os resultados observados, fígado e encéfalo mostraram-se normais em ambos os grupos...

Biomorphological alterations induced by an anti-juvenile hormonal compound, 2-(2-ethoxyethoxy)ethyl furfuryl ether, on three species of triatominae larvae (Hemiptera, Reduviidae).

Applied topically to larvae of Rhodnius prolixus Stal, Triatoma infestans (Klug) and Panstrongylus herreri Wygodzinsky, vectors of Trypanosoma cruzi, the causative agent of Chagas' disease, a synthetic, furan-containing anti-juvenile hormonal compound, 2-(2-ethoxyethoxy)ethyl furfuryl ether induced a variety of biomorphological alterations, including precocious metamorphosis into small adultoids with adult abdominal cuticle, ocelli, as well as rudimentary adultoid wings. Some adultoids died during ecdysis and were confined within the old cuticle. The extension of these biomorphological responses is discussed in terms of the complexity of the action of anti-juvenile hormonal compounds during the development of triatomines.

Ether and immobilization stress effects on pituitary adrenal function in hemidecorticate rats.

Hemidecortication (HD) (left cerebral hemisphere) was performed in rats with the aim of analyzing the modulating effect of the cerebral cortex on the hypothalamic-pituitary-adrenal axis. Corticosterone release induced either by ether or immobilization stress was evaluated in control (C) and HD rats. The percentage increase in corticosterone was greater in HD than in C rats after 15 min of ether stress (HD = 142%, C = 50%) and after 60 min of immobilization stress (HD = 197%, C = 126%). An in vitro test showed that the release of ACTH induced by corticotropin releasing hormone (CRH) from hemipituitary fragments from HD rats was not different from that in control rats. These results suggest an inhibitory effect of the cerebral cortex on the hypothalamus which may modulate the secretion of corticotropin releasing peptides.

Ventajas del etil acetato frente al eter etílico en el procesamiento del examen parasitológico de depocisiones mediante el método de Telemann modificado (MTM) / Advantages of ethyl acetate in face of ethyl eter in the procesing of parasitological examination of feces through the modified Telemann's method

Em 62 muestras de deposiciones, se practicó el método de Telemann Modificado (MTM) usando etil acetado como solvente orgánico. Se comparó su rendimiento con el MTM tradicional procesado con éter etílico en la pesquisa de parásitos intestinales. No se obtuvo diferencias en la morfología, capacidad tintorial frente a la tinción de MIF, ni en la frecuencia de hallazgos de quistes de E. histolytica, E. coli, E. nana y G. lamblia. Puesto que el etil acetato presenta ventajas prácticas sobre el eter etílico tales como su menor grado de inflamabilidad y otros, podría reemplazarlo en el procesamiento del MTM

[The ether test in leprology]. / Prova do eter em hansenologia.

The author introduces a new diagnostic technique to test skin sensitivity in hanseniasis. Sulphuric ether boils at 35 degrees C, i.e., practically at skin temperature. One gram of vaporized ether applied to the skin substracts 90 calories and causes a clear ice-cold sensation. By touching the cooled area with his fingertip the observer provokes a warm sensation. In hyposthetic skin that sensation of cold is diminished and in anesthetic areas there is no feeling of cold at all with this ether technique. The test is made with a small cotton ball wetted in sulphuric ether, which is lightly passed over the patient's skin. The subjective cooling sensation depends on the patient's information but sometimes it is accompanied by an objective "goose skin" aspect, which is especially useful when testing children and other non-cooperative persons. The technique is quite simple and much more practical and precise than the classic warm/cold tubes. It permits the mapping of the whole skin surface for disesthesic areas in a few minutes. Precautions regarding the use of ether are given.