RESUMO
ABSTRACT The virulence of four entomopathogenic nematodes strains against Bradysia mabiusi (Lane) 3º 4º instar larvae in laboratory conditions and the persistence of Heterorhabditis indica Poinar et al. 1992 on organic substrates, in the greenhouse, were evaluated. For the virulence test, four nematodes strains were used: Heterorhabditis indica IBCB-n05, Heterorhabditis sp. IBCB-n10, Steinernema glaseri CCA and S. carpocapsae CCA. These nematodes were evaluated at the dosage of 200 infective juveniles (IJ)/ larvae. For the persistence study, the nematode H. indica was selected and two tests were carried out. In the first test, the nematode was applied at the dosages of 5.7 and 22.6 IJ/cm2, and in the second, at the dosages of 10 and 50 IJ/cm2. For both tests, two evaluations were done, releasing insect larvae on the treated and nontreated substrate at 24 hours and 15 days after the application. The nematode H. indica IBCB-n05 was the most virulent, causing 100% mortality of larvae, but did not differ statistically from Heterorhabditis sp. IBCB-n10 and S. carpocapsae(96% and 83% mortality, respectively). For the first persistence test, H. indica IBCB-n05 at the dosages of 5.7 and 22.6 IJ/cm2 afforded, respectively, 67 and 80% mortality of larva (corrected by Abotts formula) 24 hours after the application. For the other persistence test, the nematode at the dosages of 10 and 50 IJ/cm2 afforded, respectively, 69 and 97% mortality (corrected by Abotts formula) 24 hs after application. The persistence of the neiological control, Sciaridae, Steinernema sp., Heterorhabditis sp., Bradysia mabiusi.
RESUMO Foi avaliada, em condições de laboratório, a virulência de quatro isolados de nematóides entomopatogênicos contra larvas de 3º e 4º instares de Bradysia mabiusi Lane, e a persistência de Heterorhabditis indica Poinar et al. 1992 em substratos orgânicos, dentro de casa de vegetação. No teste de virulência, foram avaliados os isolados H. indica IBCB-n05, Heterorhabditis sp. IBCB-n10, Steinernema glaseri CCA e S. carpocapsae CCA. Os nematóides foram usados na dosagem de 200 juvenis infectivos (JI)/larva. Para a avaliação de persistência, foi selecionado o nematóide H. indica IBCB-n05, sendo realizados 2 testes em casa de vegetação. Em um teste, o nematóide foi aplicado nas dosagens de 5,7 e 22,6 JI/cm2 e, em outro, nas dosagens de 10 e 50 JI/cm2. Nos dois testes, foram feitas duas avaliações, liberando-se larvas do inseto nas amostras tratadas do substrato após 24 horas e 15 dias da aplicação. O nematóide H. indica IBCB-n05 provocou 100% de mortalidade dos insetos, mas não diferiu significativamente do Heterorhabditis sp. IBCB-n10 e S. carpocapsae (96% e 83% de mortalidade, respectivamente). No estudo de persistência, o nematóide H. indica, nas dosagens de 5,7 e 22,6 JI/cm2, proporcionou, respectivamente, 67 e 80% de mortalidade corrigida das larvas (formula de Abott) após 24 horas da aplicação. Em outro teste, o nematóide, nas dosagens de 10 e 50 JI/cm2, proporcionou, respectivamente, 69% e 97% de mortalidade corrigida após 24 horas da aplicação. A persistência do nematóide nos testes em casa de vegetação foi bastante afetada já que a mortalidade do inseto, 15 dias após a aplicação, não passou de 15%.
RESUMO
Xylan is the principal type of hemicellulose. It is a linear polymer of beta-D-xylopyranosyl units linked by (1-4) glycosidic bonds. In nature, the polysaccharide backbone may be added to 4-O-methyl-alpha-D-glucuronopyranosyl units, acetyl groups, alpha-L-arabinofuranosyl, etc., in variable proportions. An enzymatic complex is responsible for the hydrolysis of xylan, but the main enzymes involved are endo-1,4-beta-xylanase and beta-xylosidase. These enzymes are produced by fungi, bacteria, yeast, marine algae, protozoans, snails, crustaceans, insect, seeds, etc., but the principal commercial source is filamentous fungi. Recently, there has been much industrial interest in xylan and its hydrolytic enzymatic complex, as a supplement in animal feed, for the manufacture of bread, food and drinks, textiles, bleaching of cellulose pulp, ethanol and xylitol production. This review describes some properties of xylan and its metabolism, as well as the biochemical properties of xylanases and their commercial applications.
Assuntos
Endo-1,4-beta-Xilanases/metabolismo , Fungos/enzimologia , Xilanos/metabolismo , Xilosidases/metabolismo , Endo-1,4-beta-Xilanases/química , Microbiologia Industrial , Estrutura Molecular , Xilosidases/químicaRESUMO
Pathogenesis of chronic Chagas' heart disease may include various disturbances in the coronary circulation, that could be responsible for the myocardial lesions seen in human hearts and in experimental models of the disease. In this paper we critically reviewed the anatomical and functional abnormalities described in chronic chagasic patients, pertaining to the so-called vascular pathogenetic theory of Chagas' disease. The epicardial coronary arteries are usually free of significant obstructive disease in nonselected groups of chagasic patients examined at autopsy or by coronary angiography. However, chagasic patients who were studied after an episode of acute myocardial infarction, show the same patterns of atherosclerotic coronary artery disease seen in the general nonchagasic population. Studies of chagasic patients with angiographically normal coronary arteries, by several scintigraphy methods, revealed myocardial perfusion abnormalities which may be caused by the microcirculatory derangements described in animals experimentally infected with the T. cruzi. Since hypoperfusion has been detected in regions with normal or mildly impaired wall motion, it is likely that the microvascular disturbances precede and may be causative mechanism for the subsequent myocardial damage. We speculate that hibernating ventricular areas may occur in chagasic patients, on the basis of the evidence gathered from these studies. Recent investigations of chronic patients with Chagas' disease and chest pain showed attenuation of the vasomotor responses to physiological and pharmacological stimuli, in the epicardial coronary arteries.
Assuntos
Cardiomiopatia Chagásica/fisiopatologia , Circulação Coronária/fisiologia , Animais , Cardiomiopatia Chagásica/patologia , Doença Crônica , Angiografia Coronária , Circulação Coronária/efeitos dos fármacos , Humanos , Pessoa de Meia-Idade , Infarto do Miocárdio/patologiaAssuntos
Alergia e Imunologia , Parasitologia/métodos , Filogenia , Animais , Humanos , Técnicas Imunológicas , Projetos de PesquisaRESUMO
Although few studies have reported on relatively preserved ventricular function in patient with peripartum cardiomyopathy, the condition is usually believed to have the typical low-output congestive hemodynamic pattern of the dilated congestive cardiomyopathies. Two groups of patients, 14 with peripartum cardiomyopathy and 12 with dilated congestive cardiomyopathy who were matched for gender and age, were studied. They had normal blood pressure and similar New York Heart Association functional class, nutritional status, thyroid function and routine laboratory evaluation. All patients were catheterized during stable in-hospital compensation of heart failure, which was achieved by bed rest, sodium restriction, and administration of digoxin and diuretics long (more than 3 months) after delivery. Significant differences (p less than 0.05) between patients with peripartum cardiomyopathy and those with dilated congestive cardiomyopathy were observed in regard to: (1) cardiac index: 3.34 +/- 1.36 L/min/m2 versus 2.24 +/- 0.72 L/min/m2, (2) systemic vascular resistance: 1713 +/- 567 dynes.sec.cm-5 versus 2194 +/- 603 dynes.sec.cm-5, (3) right ventricular stroke work index: 8.6 +/- 4.2 g.M/m2 versus 14.8 +/- 8.2 g.M/m2 in the peripartum cardiomyopathy and the dilated congestive cardiomyopathy groups, respectively. Three of the patients with peripartum cardiomyopathy had resting cardiac index values that were even higher than the normal upper limit for our laboratory (4.5 L/min/m2): 4.80, 5.70, and 5.63 L/min/m2. They also had nearly normal left ventricular ejection fractions: 0.68, 0.41, and 0.51, respectively. These results indicate that, unlike the common dilated cardiomyopathy, the hemodynamic pattern in patients with peripartum cardiomyopathy is not homogeneous, and some patients have high-output failure and near normal left ventricular function.
Assuntos
Débito Cardíaco , Cardiomiopatias/fisiopatologia , Cardiomiopatia Dilatada/fisiopatologia , Complicações Cardiovasculares na Gravidez/fisiopatologia , Transtornos Puerperais/fisiopatologia , Adulto , Feminino , Humanos , Gravidez , Terceiro Trimestre da Gravidez , Volume Sistólico , Resistência Vascular , Função Ventricular Esquerda , Função Ventricular DireitaRESUMO
1. It has been demonstrated that chronotropic responses differ in healthy elderly subjects compared to those in younger normal adults. To evaluate the involvement of the autonomic nervous system, we determined the number of neurons in right atrial strips from six elderly individuals (aged 77 +/- 3.4 years) five of whom had died as the result of extracardiac causes, and from younger adult controls (aged 44.0 +/- 6.0 years) who had died in traffic accidents. 2. There was a significant reduction in the number of neurons of the group of hearts from the elderly (3587 +/- 445, mean +/- SEM) compared with the control group (6412 +/- 377) of five hearts from younger adults (P less than 0.001). 3. It is suggested that this decrease in the number of neurons contributes to the reduced chronotropic responses in the aged. The mechanisms responsible for the neuronal depopulation was not determined.
Assuntos
Átrios do Coração/inervação , Neurônios/citologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Contagem de Células , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
It has been demonstrated that chronotropic responses differ in healthy elderly subjects compared to those in younger normal adults. To evaluate the involvement of the autonomic nervous system, we determined the number of neurons in right atrial strips from six elderly individuals (aged 77 + or - 3.4 years) five of whom had died as the result of extracardiac causes, and from younger adult controls (aged 44.0 + or - 6.0 years) who had died in traffic accidents. There was a significant reduction in the number of neurons of the group of hearts from the elderly (3587 + or - 445, mean + or - SEM) compared with the control group (6412 + or - 377) of five hearts from younger adults (P<0.001). It is suggested that this decrease in the number of neurons contributes to the reduced chronotropic responses in the aged. The mechanisms responsible for the neuronal depopulation was not determined
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Envelhecimento/fisiologia , Átrios do Coração/citologia , Neurônios/análise , Idoso de 80 Anos ou mais , Contagem de Células , Frequência CardíacaRESUMO
Standardized handgrip at 100% of maximal voluntary capacity was used to study heart rate responses to isometric exercise in patients with the digestive form of Chagas' disease. The chronotropic responses of the group were significantly lower (P less than 0.001) than those exhibited by control subjects, and comparable to those observed in a group of cardiac chagasic patients. These results show that severe impairment of autonomic control of the heart may occur in chagasic patients apparently having only digestive tract involvement.
Assuntos
Doença de Chagas/fisiopatologia , Acalasia Esofágica/fisiopatologia , Frequência Cardíaca , Contração Isométrica , Megacolo/fisiopatologia , Contração Muscular , Pressão Sanguínea , Cardiomiopatia Chagásica/fisiopatologia , HumanosRESUMO
Standardized handgrip at 100% of maximal voluntary capacity was used to study heart rate responses to ismetric exercise in patients with the digestive form of Chagas" disease. The chronotropic responses of the group were significantly lower (P < 0.001) than tyhose exhibited by control subjects, and comparable to those observed in a group of cardiac chagasic patient. these results show that severe impairment of autonomic control of the heart may occur in chagasic patients apparently having only digestive tract involvement
Assuntos
Humanos , Acalasia Esofágica/fisiopatologia , Doença de Chagas/fisiopatologia , Frequência Cardíaca , Contração Isométrica , Megacolo/fisiopatologia , Pressão Sanguínea , Cardiomiopatia Chagásica/fisiopatologiaAssuntos
Miocardite , Miocárdio/patologia , Animais , Gatos , Bovinos , Cricetinae , Cães , Vírus da Encefalomiocardite , Infecções por Enterovirus , Feminino , Humanos , Camundongos , Miocardite/etiologia , Miocardite/patologiaRESUMO
The results presented here show the inadequate attention that has been paid to myocarditis as a clinical entity and to employing endomyocardial biopsy examination as a valuable tool for diagnostic and research purposes. The results must be interpreted with caution, as otherwise false conclusions may be drawn as far as the epidemiological profile of cardiovascular diseases in Brazil is concerned. The data are likely to be influenced by the striking regional differences in development which are reflected in the scientific output. The high incidence of positive serology in patients in endemic areas of Trypanosoma cruzi infection is a further complication. It is possible that Chagas' disease may be overestimated clinically, decreasing therefore the interest in clarifying diseases with comparable clinical features. Myocarditis (excluding a protozoal etiology) and dilated (congestive) cardiomyopathy may serve as examples. Considering these various points, together with the complex and multi-disciplinary requirements of obtaining and interpreting catheter biopsies of the heart explains the limited clinical application of this technique in Brazil.
Assuntos
Biópsia , Endocárdio/patologia , Miocardite/patologia , Miocárdio/patologia , Biópsia/métodos , Brasil , Cardiomiopatia Dilatada/epidemiologia , Cardiomiopatia Dilatada/patologia , Cardiomiopatia Chagásica/epidemiologia , Cardiomiopatia Chagásica/patologia , Fibrose Endomiocárdica/epidemiologia , Fibrose Endomiocárdica/patologia , Humanos , Miocardite/epidemiologiaRESUMO
The sensitivity of baroreflex bradycardia and tachycardia was determined in fourteen patients with Chagas' disease who seemed to be normal with respect to cardiac autonomic control evaluated in terms of heart rate responses to the conventional atropinization and Valsalva maneuver tests. Eleven normal subjects were studied for comparison. Baroreflex sensitivity was determined by relating the beat-to-beat pulse intervals to systolic pressure values during transient phenylephrine- and amyl nitrite-induced changes in arterial pressure. Chagasic patients showed mean bradycardia sensitivity (10.1 +/- 1.3 ms/mmHg) which was significantly lower than that obtained for the control group (16.7 +/- 2.1 ms/mmHg). When only the subgroup of ten patients with overt disease (cardiac and/or digestive form) was considered, the value fell to 8.6 +/- 1.4 ms/mmHg. The lowest individual values were exhibited by the majority of patients with exclusive cardiac or associated cardiac and digestive disease. Patients with only digestive disease or without overt disease (indeterminate form) had values within the normal range. Tachycardia sensitivity (6.3 +/- 0.8 ms/mmHg) was similar to that obtained for the control group (6.6 +/- 1.0 ms/mmHg). Only one patient with associated disease presented a reduced value. These data show that the estimation of baroreflex sensitivity can be used to identify impaired cardiac autonomic control in chronic Chagas' disease not detectable by conventional tests. The reduced baroreflex sensitivity appears to be due to the subtle impairment of the parasympathetic influence on the heart. Furthermore, there is a relationship between the degree of baroreflex sensitivity and the clinical form of organic involvement in Chagas' disease.