RESUMO
Plants used in traditional medicine are rich sources of hemolysins and cytolysins, which are potential bactericidal and anticancer drugs. The present study demonstrates for the first time the presence of a hemolysin in the leaves of Passiflora quadrangularis L. This hemolysin is heat stable, resistant to trypsin treatment, has the capacity to froth, and acts very rapidly. The hemolysin activity is dose-dependent, with a slope greater than 1 in a double-logarithmic plot. Polyethylene glycols of high molecular weight were able to reduce the rate of hemolysis, while liposomes containing cholesterol completely inhibited it. In contrast, liposomes containing phosphatidylcholine were ineffective. The Passiflora hemolysin markedly increased the conductance of planar lipid bilayers containing cholesterol but was ineffective in cholesterol-free bilayers. Successive extraction of the crude hemolysin with n-hexane, chloroform, ethyl acetate, and n-butanol resulted in a 10-fold purification, with the hemolytic activity being recovered in the n-butanol fraction. The data suggest that membrane cholesterol is the primary target for this hemolysin and that several hemolysin molecules form a large transmembrane water pore. The properties of the Passiflora hemolysin, such as its frothing ability, positive color reaction with vanillin, selective extraction with n-butanol, HPLC profile, cholesterol-dependent membrane susceptibility, formation of a stable complex with cholesterol, and rapid erythrocyte lysis kinetics indicate that it is probably a saponin.
Assuntos
Colesterol/metabolismo , Eritrócitos/metabolismo , Proteínas Hemolisinas/farmacologia , Passiflora/química , Saponinas/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Eritrócitos/efeitos dos fármacos , Proteínas Hemolisinas/isolamento & purificação , Hemólise , Bicamadas Lipídicas/metabolismo , Extratos Vegetais/farmacologia , Folhas de Planta/química , Coelhos , Saponinas/isolamento & purificaçãoRESUMO
Plants used in traditional medicine are rich sources of hemolysins and cytolysins, which are potential bactericidal and anticancer drugs. The present study demonstrates for the first time the presence of a hemolysin in the leaves of Passiflora quadrangularis L. This hemolysin is heat stable, resistant to trypsin treatment, has the capacity to froth, and acts very rapidly. The hemolysin activity is dose-dependent, with a slope greater than 1 in a double-logarithmic plot. Polyethylene glycols of high molecular weight were able to reduce the rate of hemolysis, while liposomes containing cholesterol completely inhibited it. In contrast, liposomes containing phosphatidylcholine were ineffective. The Passiflora hemolysin markedly increased the conductance of planar lipid bilayers containing cholesterol but was ineffective in cholesterol-free bilayers. Successive extraction of the crude hemolysin with n-hexane, chloroform, ethyl acetate, and n-butanol resulted in a 10-fold purification, with the hemolytic activity being recovered in the n-butanol fraction. The data suggest that membrane cholesterol is the primary target for this hemolysin and that several hemolysin molecules form a large transmembrane water pore. The properties of the Passiflora hemolysin, such as its frothing ability, positive color reaction with vanillin, selective extraction with n-butanol, HPLC profile, cholesterol-dependent membrane susceptibility, formation of a stable complex with cholesterol, and rapid erythrocyte lysis kinetics indicate that it is probably a saponin.
Assuntos
Animais , Coelhos , Colesterol/metabolismo , Eritrócitos/metabolismo , Proteínas Hemolisinas/farmacologia , Passiflora/química , Saponinas/farmacologia , Cromatografia Líquida de Alta Pressão , Eritrócitos/efeitos dos fármacos , Hemólise , Proteínas Hemolisinas/isolamento & purificação , Bicamadas Lipídicas/metabolismo , Extratos Vegetais/farmacologia , Folhas de Planta/química , Saponinas/isolamento & purificaçãoRESUMO
Concentrations of calcium and magnesium were measured in mature milk, collected between 30 and 90 days after childbirth, from a group of 90 mothers between 14 and 39 years of age, exclusively breastfeeding. The group was divided into three sub-groups: low socioeconomic-level adolescents (LSAd), low socioeconomic-level adults (LSA), and high socioeconomic-level adults (HSA). Each mother's nutritional status was determined using the body-mass index (BMI) and her eating habits, obtained on the basis of a 24-h dietary recall. Adolescent and adult mothers in the low socioeconomic-level group had lower average calcium intake (LSAd = 618.4 +/- 555.2 mg and LSA = 679.4 +/- 411.4 mg) than adult mothers in the higher socioeconomic-level group (853.6 +/- 415.5 mg). The average concentration of calcium in the adolescent mothers' milk (LSAd) was significantly lower (5.30 +/- 1.42 mmol Ca/L, P = 0.01) than that of the two adult groups (LSA = 5.82 +/- 1.55 mmol Ca/L and HSA = 6.40 mmol Ca/L). The average magnesium concentrations for all groups did not show significant differences (LSAd = 1.06 +/- 0.18, LSA = 1.16 +/- 0.23 and HSA = 1.11 +/- 0.23 mmol Mg/L, for P= 0.16). These results indicate that magnesium concentrations in mature human milk do not seem to depend on maternal nutritional status. The condition of adolescence, however, associated with lower calcium intake by the mother, resulted in lower calcium concentrations in the milk secreted when compared to that of adult mothers.
Assuntos
Cálcio da Dieta/análise , Cálcio/análise , Magnésio/análise , Leite Humano/química , Adolescente , Adulto , Fatores Etários , Ingestão de Alimentos , Comportamento Alimentar , Feminino , Humanos , Estado Nutricional , Classe SocialRESUMO
The variation of resistance to (60)Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell (60)Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL(50/30) = 218.2 Gy) was found greater than in cross-fecundation forms. These data point to a low radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon.
Assuntos
Biomphalaria/efeitos da radiação , Raios gama , Animais , Biomphalaria/fisiologia , Dose Letal Mediana , Reprodução/efeitos da radiaçãoRESUMO
Because home total parenteral nutrition (TPN) is not available to most of the Brazilian population, an alternative treatment for short bowel syndrome was evaluated. Four patients ages 40-65 y (mean: 53.75 +/- 10.59), three with mesenteric thrombosis, and one with Crohn's disease were studied. The average length of the remaining small bowel in these patients was 54.5 +/- 6.4 cm; the ileocecal valve was preserved in 3 cases. A progressive step diet was used for intestinal adaptation. Administration of pectin was started at the beginning of the special oral diet (step 1), followed by medium-chain triacylglycerols (MCTs) and complex, nonfermentable sugars (step 2); coconut oil (47% MCTs) and simple sugars (step 3); and long-chain triacylglycerols and lactose (step 4). TPN was interrupted at step 3 or 4 when the energy content of the diet reached 150% of the patient's resting energy expenditure, if serum albumin and weight were stable or increasing, and if the frequency, amount, and consistency of stools remained unchanged. Nutritional follow-up showed that patients responded well to this approach; also, patients returned to their previous professional activities. Thus, enteral formulas were not essential for gastrointestinal adaptation. Home TPN should not be indicated on the basis of strict criteria, but rather when a patient fails to adapt to a progressive, special oral diet.