Hormonal therapy with estradiol and drospirenone improves endothelium-dependent vasodilation in the coronary bed of ovariectomized spontaneously hypertensive rats

Drospirenone (DRSP) is a progestin with anti-aldosterone properties and it reduces blood pressure in hypertensive women. However, the effects of DRSP on endothelium-dependent coronary vasodilation have not been evaluated. This study investigated the effects of combined therapy with estrogen (E2) and DRSP on endothelium-dependent vasodilation of the coronary bed of ovariectomized (OVX) spontaneously hypertensive rats. Female spontaneously hypertensive rats (n=87) at 12 weeks of age were randomly divided into sham operated (Sham), OVX, OVX treated with E2 (E2), and OVX treated with E2 and DRSP (E2+DRSP) groups. Hemodynamic parameters were directly evaluated by catheter insertion into the femoral artery. Endothelium-dependent vasodilation in response to bradykinin in the coronary arterial bed was assessed using isolated hearts according to a modified Langendorff method. Coronary protein expression of endothelial nitric oxide synthase and estrogen receptor alpha (ER-α) was assessed by Western blotting. Histological slices of coronary arteries were stained with hematoxylin and eosin, and morphometric parameters were analyzed. Oxidative stress was assessed in situ by dihydroethidium fluorescence. Ovariectomy increased systolic blood pressure, which was only prevented by E2+DRSP treatment. Estrogen deficiency caused endothelial dysfunction, which was prevented by both treatments. However, the vasodilator response in the E2+DRSP group was significantly higher at the three highest concentrations compared with the OVX group. Reduced ER-α expression in OVX rats was restored by both treatments. Morphometric parameters and oxidative stress were augmented by OVX and reduced by E2 and E2+DRSP treatments. Hormonal therapy with E2 and DRSP may be an important therapeutic option in the prevention of coronary heart disease in hypertensive post-menopausal women.

Deficiency of sex hormones does not affect 17-ß-estradiol-induced coronary vasodilation in the isolated rat heart

The relaxation of coronary arteries by estrogens in the coronary vascular beds of naive and hypertensive rats has been well described. However, little is known about this action in gonadectomized rats. We investigated the effect of 17-ß-estradiol (E2) in coronary arteries from gonadectomized rats, as well as the contributions of endothelium-derived factors and potassium channels. Eight-week-old female and male Wistar rats weighing 220-300 g were divided into sham-operated and gonadectomized groups (n=9−12 animals per group). The baseline coronary perfusion pressure (CPP) was determined, and the vasoactive effects of 10 μM E2 were assessed by bolus administration before and after endothelium denudation or by perfusion with NG-nitro-L-arginine methyl ester (L-NAME), indomethacin, clotrimazole, L-NAME plus indomethacin, L-NAME plus clotrimazole or tetraethylammonium (TEA). The CPP differed significantly between the female and sham-operated male animals. Gonadectomy reduced the CPP only in female rats. Differences in E2-induced relaxation were observed between the female and male animals, but male castration did not alter this response. For both sexes, the relaxation response to E2 was, at least partly, endothelium-dependent. The response to E2 was reduced only in the sham-operated female rats treated with L-NAME. However, in the presence of indomethacin, clotrimazole, L-NAME plus indomethacin or L-NAME plus clotrimazole, or TEA, the E2 response was significantly reduced in all groups. These results highlight the importance of prostacyclin, endothelium-derived hyperpolarizing factor, and potassium channels in the relaxation response of coronary arteries to E2 in all groups, whereas nitric oxide may have had an important role only in the sham-operated female group.

Premature thelarche: identification of clinical and laboratory data for the diagnosis of precocious puberty

PURPOSE: Two groups of girls with premature breast development were studied retrospectively. We tried to identify clinical, radiological, and hormonal parameters that could distinguish between a benign, nonprogressive premature thelarche and a true precocious puberty. METHODS: The clinical outcome of 88 girls with breast enlargement before 6.1 years of age was analyzed. Taking into account the progression of their sexual maturation, we allocated the children into 2 groups: "Isolated Premature Thelarche" (n = 63) and "Precocious Puberty" (n = 25) groups. Chronological and bone ages, height and growth velocity centiles, computerized tomography of hypothalamus-pituitary area, pelvic ultrasonography, gonadotropin response to luteinizing hormone-releasing hormone stimulation as well as basal levels of luteinizing hormone, follicle-stimulating hormone, estradiol, and prolactin were studied in both groups. Statistical analysis were performed using the Student t test to compare the sample means. Fisher's exact test and chi² test were used to analyze the nonparametric variables. RESULTS: Isolated premature thelarche most frequently affected girls younger than 2 years who presented exaggerated follicle-stimulating hormone response to luteinizing hormone-releasing hormone stimulation test. The precocious puberty group had higher initial stature, accelerated growth rate and bone age, increased uterine and ovarian volumes, high spontaneous luteinizing hormone levels by immunofluorimetric assay, as well as a high luteinizing hormone response and peak luteinizing hormone/follicle-stimulating hormone ratio after luteinizing hormone-releasing hormone stimulation. CONCLUSION: At initial presentation, girls who undergo true precocious puberty present advanced bone age, increased uterine and ovarian volumes in addition to breast enlargement, as well as an luteinizing hormone-predominant response after a luteinizing hormone-releasing hormone stimulation test.

Euglossine Bees (Hymenoptera: Apidae) of Buriticupu, Amazonia of Maranhão, Brazil1

Male euglossine bees attracted to cineole, vanillin, methyl salicylate, eugenol and benzyl benzoate, were collected from October 1995 to September 1996, twice a month, between 06.00 and 12.00 hours, at the Companhia Vale do Rio Doce Forest Reserve, Buriticupu-MA. It were sampled 1740 individuals, 37 species and 4 genera. Euglossa was the most abundant genus (23 species), followed by Eufriesea (8), Eulaema (4) and Exaerete (2). The most frequent species were Euglossa pleosticta (33% of the collected individuals), Euglossa truncata (12,7%), Euglossa avicula (6,3%), Eufriesea superba (5,2%), Euglossa fimbriata (4,8%) Euglossa violaceifrons (4,4%), Eulaema nigrita (4,1%), Euglossa cordata (4,0%), Eulaema meriana (3,4%). Cineole attracted 66% of males and 70% of species, vanillin (20%; 59%), methyl salicylate (7,4%; 54%), eugenol (5,6%; 44%) and benzyl benzoate (0,7%; 10,8%). The highest abundance of individuals (78,3%) and species (34) occurred in the rainy season (January-June). The species of the genus Eufriesea occurred only in this period. Regarding the hourly activity, the euglossine bees were more frequently found between 10.00 and 11.00 hours, accounting for 33,5% of the individuals and 86,4% of the species.

Aspectos reprodutivos e perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas (SCHINZ,1822), em condições de cativeiro

Esta pesquisa teve como objetivo caracterizar a reprodução e o perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas, além de validar um aspecto do dimorfismo sexual secundário. O experimento foi realizado na Fazenda Santo Antônio II, em Presidente Figueredo-AM, no período de fevereiro de 2004 a fevereiro de 2005. Foram selecionados 24 exemplares e divididos em três grupos de oito peixes (grupo "A", "B" e "C" com pirarucus de mais de quatro anos de idade, com três anos e dois anos, respectivamente). Os pirarucus foram estocados em três tanques de 400m², um para cada grupo. Aspectos comportamentais, como o interesse por alimento, brigas, formação de casais e presença de ninhos, foram observados ao longo de todo o experimento. Amostras de sangue foram coletadas mensalmente, de todos os peixes, observou-se a presença de uma mancha alaranjada no macho como uma característica sexual secundária. Foram mensurados os níveis de testosterona (T), 17beta-estradiol (E2) e 17alfa-hidroxi-progesterona (17aOHP) através de radioimunoensaio (RIA) de fase sólida. Todos os machos dos grupos "A" e "B" puderam ser identificados pela mancha alaranjada na região inferior da cabeça, corroborada pela concentração de testosterona, comprovando o conhecimento empírico dos ribeirinhos. Os níveis de T e E2 nos peixes do grupo "A" e "B" tiveram maiores picos no início do período de chuva, enquanto que o 17aOHP teve oscilações constantes e pequenos picos no final do período chuvoso, os peixes do grupo "C" acompanharam essa tendência em concentrações menores.

Enzimas no testículo de ratos em algumas condições experimentais

Dosou-se a atividade da GOT, GPT e ceruloplasmina no testículo de ratos normais (a atividade testicular destas enzimas é relativamente baixa) e injetados com cloreto de cádmio ( que lesa o testículo), assim como em animais com este órgão lesado e que se administrou testosterona, estradiol, progesterona e gonadotrofina coriônica. Pudemos observar alterações significativas das enzimas por ação destes diferentes hormônios. Infelizmente, como pouco se sabe sobre a função destas enzimas neste órgão, torna-se difícil interpretar os nossos achados.

Molecular aspects of Schistosoma mansoni female maturation

Incubation of total protein extracts of Schistosoma mansoni with 3H 17-beta-estradiol and 20-hydroxyecdysone, revealed steroid binding proteins in both, male and female worms. The interaction of nuclear proteins with restriction fragments of the gender and stage-specific gene F-10 was investigated using the "Band-Shift" technique. Distinct male and female nuclear proteins bound to the fragments of this gene. Among the nuclear proteins, only those rich in cysteine residues bound to DNA. In vitro incubation of live worms with the estrogen antagonist Tamoxifen, altered the pattern of the DNA binding proteins, producing in females, a band profile similar to that obtained with male worm protein extracts. When Tamoxifen was injected into schistosome infected mice, the eggs produced by females presented an abnormal morphology, compatible with non-viable eggs. These results suggest that the regulation of transcription of the F-10 gene might involve steroid receptors.

The schistosome enzyme that activates oxamniquine has the characteristics of a sulfotransferase

Available evidence suggests that the antischistosomal drug oxamniquine is converted to a reactive ester by a schistosome enzyme that is missing in drug-resistant parasites. This study presents data supporting the idea that the active ester is a sulfate and the activating enzyme is a sulfotransferase. Evidence comes from the fact that the parasite extract loses its activating capability upon dialysis, implying the requirement of some dialyzable cofactor. The addition of the sulfate donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) restored activity of the dialyzate, a strong indication that a sulfotransferase is probably involved. Classical sulfotransferase substrates like beta-estradiol and quercetin competitively inhibited the activation of oxamniquine. Furthermore, these substrates could be sulfonated in vitro using an extract of sensitive (but not resistant) schistosomes. Gel filtration analysis showed that the activating factor eluted in a fraction corresponding to a molecular mass of about 32 kDa, which is the average size of typical sulfotransferase subunits. Ion exchange and affinity chromatography confirmed the sulfotransferase nature of the enzyme. Putative sulfotransferases present in schistosome databases are being examined for their possible role as oxamniquine activators.

Comunidade de Euglossini (Hymenoptera, Apidae) das dunas litorâneas do Abaeté, Salvador, Bahia, Brasil

Community of Euglossini (Hymenoptera, Apidae) from the coastal sand dunes of Abaeté, Salvador, Bahia, Brazil. The Euglossini community structure was analyzed by attracting males with the scents eucalyptol, eugenol, vanillin, benzyl benzoate and methyl salicylate, and by netting bees on flowers. The samplings took place three times a month along one year from 6:00 a.m. to 6:00 p.m. The scent baits attracted 670 individuals belonging to seven species of three genus. The predominant species were Euglossa cordata (Linnaeus, 1758) (76.6%) and Eulaema nigrita Lepeletier, 1841 (21.8%). Euglossini males visited the scents along the whole year, being more abundant in May and in August. The most efficient fragrance was eucalyptol, attracting 624 individuals of five species. The males abundance fluctuated along the day, being the highest frequency observed between 8:00 a.m. to 10:00 a.m. Forty eigth Euglossini females of four species were netted visiting flowers of 14 plant species belonging to 13 families. Solanaceae and Caesalpiniaceae were the most visited. The species catched on flowers were Euglossa cordata, Eulaema nigrita, Euplusia mussitans (Fabricius, 1787) and Eulaema meriana flavescens Friese 1899. Euglossa cordata was the predominant species on flowers (64.6%), being collected during almost the whole year. Euplusia mussitans was the only species netted on flowers which males were not sampled on the scents.

Comparação dos padrões de atratividade de Hermetia illucens (Diptera, Stratiomyidae) associada a carcaças de Rattus norvergicus enterradas e tratadas com hormônios esteróides

Hermetia illucens (L.) (Diptera, Stratiomyidae) é uma espécie abundante em todo o continente americano. No entanto, ainda há poucos estudos no Brasil abordando aspectos em relação a sua biologia e ecologia, em particular associados a estudos forenses. Neste trabalho, nós observamos os efeitos de hormônios esteróides na decomposição corporal de Rattus norvergicus, variedade Wistar enterrados na atração de H. illucens. Além da presença de diversas espécies de larvas e adultos de insetos freqüentemente encontrados em carcaças nessas condições, observou-se uma grande quantidade de imaturos de H. illucens. Essa espécie representou aproximadamente 22% de todos os espécimes coletados, tendo aparecido somente nos animais que receberam tratamento com esteróides sexuais dos tipos testosterona, progesterona e estradiol. Dentre esses, a maior abundância foi verificada nos que haviam recebido testosterona (68%). A presença de imaturos de H. illucens, apenas nos animais que receberam o tratamento com esteróides, em experimentos realizados em dois anos consecutivos revela uma possível atração/seleção dessa espécie por corpos com quantidades aumentadas de hormônios sexuais. Esse comportamento pode ser particularmente útil para a entomologia forense no que diz respeito à estimativa do intervalo pós-morte (IPM), particularmente quando tem como base informações sobre o ciclo de vida e ecologia de insetos necrófagos.

Desempenho reprodutivo de porcas submetidas a infusões uterinas no início do estro

O objetivo deste trabalho foi avaliar o desempenho reprodutivo de porcas multíparas submetidas à infusão uterina de diferentes soluções, realizada no início do estro. Um total de 1.019 fêmeas foram controladas no período de verão (n=570) e inverno (n=449). Os animais foram submetidos a cinco tratamentos, que consistiram em infusão de plasma seminal (PS), sêmen morto (SM), solução de 17beta-estradiol (SE), solução fisiológica (SS) e um grupo-controle (CO). As fêmeas receberam três inseminações: a primeira, 8-12 horas após a detecção do estro, e as demais, nos turnos subseqüentes. Com relação à taxa de retorno ao estro e taxa de parto ajustada, não ocorreram diferenças entre os tratamentos (p>0,05). Na análise do modelo de regressão adotado para determinar o tamanho da leitegada, foi observada uma interação entre época do ano e tratamento (p<=0,01). No verão, as fêmeas que receberam infusão de PS apresentaram 0,89, 1,20, 1,34 e 2,31 leitões a mais, em relação aos tratamentos SE, SM, SS e CO (p<0,05), respectivamente. No inverno, o grupo submetido ao tratamento SS aumentou a produção em 1,25 e 0,91 leitões, respectivamente, em relação aos tratamentos SM e CO (p<0,05). Este trabalho demonstrou que a infusão uterina de PS foi eficiente somente no verão, para aumentar o número de leitões nascidos. Entretanto, são necessários estudos complementares esclarecendo o efeito deste tratamento em épocas do ano distintas e em diferentes ordens de parto.

Concentrações séricas hormonais em vacas azebuadas submetidas à baixa e alta ingestão alimentar

O objetivo deste trabalho foi avaliar a influência da ingestão alimentar nas concentrações séricas de hormônios reprodutivos e metabólicos em vacas azebuadas. Dezoito vacas foram divididas em dois grupos: 170% (alta ingestão = A) e 66% (baixa ingestão = B) da dieta de manutenção. Com 21 dias nas dietas experimentais, as vacas tiveram o estro sincronizado. Posteriormente, os ovários foram avaliados por ultra-sonografia transretal e sangue foi coletado diariamente até o dia 7 do ciclo (ovulação = dia 1). Na análise estatística, utilizou-se o teste t. As vacas ganharam 1,1 kg por dia no grupo A e perderam 1,5 kg por dia de PV no grupo B. Apesar de não ter havido diferença entre os grupos no diâmetro máximo do folículo ovulatório, o grupo A apresentou pico pré-ovulatório de estradiol sérico menor. Não foi observada diferença entre os grupos quanto ao volume luteal e concentração sérica de progesterona no dia 7 do ciclo e de FSH, IGF-I e insulina séricos no período peri-ovulatório. As dietas experimentais não alteraram a função ovariana e as concentrações séricas de hormônios reprodutivos e metabólicos, com exceção do estradiol, sugerindo que, no grupo de alta ingestão, ocorreu maior metabolismo desse hormônio.

Síntese do isobutileno e seu emprego em reações de esterificação: propostas de aulas práticas de química orgânica para a graduação

An experiment for the synthesis of isobutylene from tert-butanol dehydratation using oxalic acid as catalyst, followed by preparations of tert-butyl benzoate and tert-butyl cinnamate is described. The synthesis are simple, requiring two periods of 4 hours and are suitable for undergraduate organic chemistry experimental courses.

Synthesis, characterization and thermal behaviour of solid-state compounds of benzoates with some bivalent transition metal ions

Solid-state MBz compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu and Zn and Bz is benzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The procedure used in the preparation of the compounds via reaction of basic carbonates with benzoic acid is not efficient in eliminating excess acid. However the TG-DTA curves permitted to verify that the binary compounds can be obtained by thermosynthesis, because the benzoic acid can be eliminated before the thermal decomposition of these compounds. The results led to information about the composition, dehydration, thermal stability, thermal decomposition and structure of the isolated compounds. On heating, these compounds decompose in two (Mn, Co, Ni, Zn) or three (Fe, Cu) steps with formation of the respective oxide (Mn3O4, Fe2O3, Co3O4, NiO, CuO and ZnO) as final residue. The theoretical and experimental spectroscopic studies suggest a covalent bidentate bond between ligand and metallic center.

Piranoflavonas inéditas e atividades tripanocidas das substâncias isoladas de conchocarpus heterophyllus

The phytochemical investigation of trypanocidal extracts from leaves and stems of Conchocarpus heterophyllus (A. St.-Hil.) Kallunki & Pirani (Rutaceae) afforded new pyranoflavones along with the known compounds flavone, 7-methoxyflavone, 5-hydroxyflavone, haplotusine, 1-methyl-2-phenyl-4-quinolone alkaloid, beta-sitosterol, stigmasterol, and beta-sitosteryl benzoate. Their structures were established based on their spectral data. NMR data for the alkaloid haplotusine and the new pyranoflavones are described for the first time herein. These compounds were assayed on the tripomastigote forms of Trypanosoma cruzi. Among them, haplotusine and 1-methyl-2-phenyl-4-quinolone showed moderate values of IC50 136.9 and 144.9 mM, respectively.