Showing papers by "Universidade Federal de Minas Gerais published in 1977"
TL;DR: In mice experimentally infected with Schistosoma mansoni, praziquantel (2-cyclohexylcarbonyl-1,3,4,6,7,11b-hexahydro-2H-pyrazino[2,1-a]isoquinoline-4-one), administered orally at the levels of 100 and 50 mg/kg, for 5 consecutive days, produces oogram changes in all animals and a pronounced hepatic shift
Abstract: In mice experimentally infected with Schistosoma mansoni, praziquantel (2-cyclohexylcarbonyl-1,3,4,6,7,11b-hexahydro-2H-pyrazino[2,1-a]isoquinoline-4-one), administered orally at the levels of 100 and 50 mg/kg, for 5 consecutive days, produced oogram changes in all animals and a pronounced hepatic shift of schistosomes (97.1 and 89.1, respectively). At lowest levels (12.5 and 6.3 mg/kg), alterations in the oogram could still be detected, although hepatic shift of schistosomes was no more evident. After a single intramuscular injection, the results obtained paralleled those observed with a single-dose oral treatment. The hepatic shift was only moderate at 200 and 100 mg/kg and the percentages of worms retained in the liver, after perfusion, were particularly low. When nasal route in a 1-day regimen was used, the results obtained were slightly less evident as compared with those observed by oral route (5-day schedule). Considering the percentage of oogram changes, the degree of hepatic shift of schistosomes and the percentage of worms fixed in the liver, the antischistosomal activity of praziquantel was greater in hamsters than in mice. Actually, a daily dose as low as 12.5 mg/kg, administered for 5 consecutive days, was sufficient to shift 60.4% of the worms towards the liver and to produce alterations of the oogram in 60% of the animals. In Cebus monkeys orally treated with 10 and 20 mg/kg of praziquantel, given 3 times within a single day (total doses of 30 and 60 mg/kg, respectively), a remarkable reduction in worm burden was observed. A single oral or intramuscular dose of 100 mg/kg was found to be curative. One Cebus dosed with 100 mg/kg, by nasal spray, was found to harbor only female worms at autopsy performed 69 days after treatment.
76 citations
TL;DR: It is concluded that there is a definite increase in negative surface charge during development from epi- to trypomastigote forms of T. cruzi.
Abstract: SYNOPSIS The surface charge of epimastigote and trypomastigote forms of Trypanosoma cruzi was evaluated by means of binding of cationized ferritin to the cell surface as visualized by electron microscopy, and by direct measurements of the cellular microelectrophoretic mobility (EPM). Epimastigote forms had a mean EPM of -0.52 μm.s-1.V-1.cm and were lightly labeled with cationized ferritin. In contrast, bloodstream trypomastigotes had a much higher EPM (-1.14), and the surface was heavily labeled with cationized ferritin. When trypomastigotes from stationary phase cultures were isolated on DEAE cellulose columns, the mean EPM was found to be significantly lower (-0.63), and labeling with cationized ferritin decreased. With a mixed population containing epimastigote, trypomastigote, and intermediate forms, EPM values ranging between -0.70 to -1.14 were found. From these observations we conclude that there is a definite increase in negative surface charge during development from epi- to trypomastigote forms of T. cruzi.
70 citations
TL;DR: In this paper, the structure of (5S,6S)-6(or 5)-hydroxymethyl-5(or 6)-(4″-hydroxy-3″-methoxyphenyl)-2,3:3:4′,4′-(2′)-methoxyxanthono)-1,4-dioxane was proposed for kielcorin by analysis of high resolution MS and PMR spectra.
56 citations
TL;DR: On the basis of present evidence the 5-carbon atom side chain present in naturally occurring lapachol seems to be important for activity, and this is in accord with the previous observation that effective protective agents are liposoluble.
Abstract: Skin penetration by Schistosoma mansoni cercariae may be blocked by 1,4-and 1,2-naphthoquinones applied topically. Of 23 naphthoquinone derivatives synthesized, 15 afforded almost complete protection when applied in solution to the tails of mice 24 hours before exposure to cercariae. On the basis of present evidence the 5-carbon atom side chain present in naturally occurring lapachol seems to be important for activity, and this is in accord with the previous observation that effective protective agents are liposoluble. Topically applied cercarial penetration inhibitors are presently the only prophylactic agents available for use in the field.
45 citations
TL;DR: Protein synthesis during early development of Schistosoma mansoni larva was investigated in vitro and assessed by labelled amino-acid incorporation and proteins of tegument incorporated 2–3 times more isotope than those of the larval body.
Abstract: 1. 1. Protein synthesis during early development of Schistosoma mansoni larva was investigated in vitro and assessed by labelled amino-acid incorporation. 2. 2. The rate of protein synthesis was low at the first 6 hr, increasing gradually as the time elapsed. 3. 3. The rate of 14 C-leucine incorporation was strongly dependent on the enrichment of the incubation media with an amino-acid mixture. 4. 4. The protein synthesis was not affected by the addition of 100 and 200 μg/ml of cycloheximide and chloroamphenicol to the incubation media. On the other hand, puromycin (500 μg/ml) and actinomycin (0.65–1.30 μg/ml) strongly inhibited protein synthesis. 5. 5. Proteins of tegument incorporated 2–3 times more isotope than those of the larval body.
21 citations
TL;DR: In mice whose chronic phase was induced by trypomastigotes of the Y strain, malaria infections did not induce a typical acute phas with high parasitemia by T. cruzi, speculates on mechanisms which allow malaria infections selectively to suppress acquired host resistance to certain strains of T.cruzi.
Abstract: SYNOPSIS. The effect of malaria on the chronic phase of Chagas’disease was investigated in mice. The animals were given Plasmodium berghei-infected red blood cells 2 to 12 months after their initial inoculation with trypomastigotes of 3 different strains of Trypanosoma cruzi (Y, CL and Gilmar). In all the experiments carried out with one of the strains (CL), a somewhat variable but always considerable percentage of mice (average 39%) relapsed in to the acute phase of Chagas’disease. This relapse was characterized by a significant increase in the number of circulating trypomastigotes. Recrudescence was observed also with a 2nd strain of T. cruzi (Gilmar), which is similar in many aspects to the CL strain, e.g. the morphology of blood stages, curve of parasitemia and susceptibility to antibodies in vitro. In mice whose chronic phase was induced by trypomastigotes of the Y strain, malaria infections did not induce a typical acute phase with high parasitemia by T. cruzi. Bloodstream forms of Y parasites differ from those of CL and Gilmar strains morphologically as well as immunologically, i.e. only the Y strain is easily agglutinated and partly inactivated by specific immune serum. In light of this and other known characteristics of the strains used in the present work, the author speculates on mechanisms which allow malaria infections selectively to suppress acquired host resistance to certain strains of T. cruzi.
15 citations
TL;DR: The results indicate that the hypotensive effect and the early respiratory arrhythmias induced by intracerebroventricular TsTX are related to central muscarinic mechanisms.
13 citations
TL;DR: Glycoprotein secretion in the mouse submandibular gland was investigated by light microscope radioautography of semi-thin sections after the administration of L-3H-fucose to find glycoproteins synthesized by the intercalated, secretory, striated and excretory ducts seem to renew continuously.
Abstract: Glycoprotein secretion in the mouse submandibular gland was investigated by light microscope radioautography of semi-thin sections after the administration of L-3H-fucose. The incorporation of the precursor in the acini was negligible. 3H-fucose was taken up in the paranuclear region of the cells lining the intercalated, secretory, striated and excretory ducts. This labeling pattern was interpreted as addition of the precursor to glycoproteins within the Golgi apparatus. Incorporation in the intercalated duct was restricted to the cells with fine cytoplasmic granules. The glycoproteins synthesized by the intercalated and secretory ducts were transported to the saliva by the secretion granules. It is assumed that the glycoproteins synthesized in the striated and excretory ducts are plasma membrane glycoproteins which seem to renew continuously. Quantitation of the radioautographs supplied data concerning the incorporation of 3H-fucose into newly synthesized glycoproteins as well as the renewal of the labeled macromolecules in each duct.
13 citations
TL;DR: In this article, it is shown that in the absence of crystalline distortion induced by the motion of the tunneling ion, the only stable ordered phase is that of symmetry C 3v.
Abstract: Thermodynamical properties of an order-disorder model of ferroelectrics proposed by Comes, Lambert and Guinier for the perovskites BaTiO3 and KNbO3, are discussed It is shown that in the absence of crystalline distortion induced by the motion of the tunneling ion, the only stable ordered phase is that of symmetry C 3v The ferroelectric-paraelectric transition is a “super-singular” point where the paraelectric phase coexists with three ferroelectric phases The lattice distortion breaks this degeneracy; unless the distortion is too drastic the system then shows three ferroelectric phases of symmetries C 3v, C 2v and C 4v, appearing in this order for increasing temperature, in complete agreement with BaTiO3 and KNbO3 The calculated entropy changes associated to the phase transformation are consistently larger than the measured values, showing that a correlation between the configurations of neighboring cells is an essential feature of the model Calculation details were published in Phys Rev B
11 citations
TL;DR: There is a definite need for a large‐scale epidemiological investigation to clarify this possible association with liver tumors associated with the intake of male hormones as anabolic steroids and oral contraceptives.
Abstract: Since 1973, there has been an increase in the reported number of cases of liver tumors (both benign and malignant), associated with the intake of male hormones as anabolic steroids and oral contraceptives. Because these tumors are very rare in the younger age groups, and because there are approximately 50 million women taking oral contraceptives at the present time, there is a definite need for a large-scale epidemiological investigation to clarify this possible association.
9 citations
TL;DR: A trunk wood sample from the vicinity of Manaus was freed from bark, ground and extracted with benzene as mentioned in this paper, the extractor was chromatographed on a silica column, g 1vmg successively with the indicated solvents : A, and A2 (benzene-EtOH 98:2), A3 and A.
Abstract: A trunk wood sample from the vicinity of Manaus was freed from bark, ground and extracted with benzene. The ext ract (8% , 41g) was chromatographed on a silica column, g1vmg successively the following useful fractions with the indicated solvents : A, and A2 (benzene-EtOH 98:2), A3 and A. (benzene·EtOH 96:4), As and As (benzene-EtOH 94:6). A, w as rechromatographed on florisil giving a red band w hich, extruded and extracted with CHCb, gave physcion (1 ,8-dihydroxy-6-methoxy-3-methylanthraquinone, 5 mg), m. p. and l it. [ Eder & Hauser, 1925] m .p . 205-207° . A2 was freed from oil by chromatography on s:lica givi ng I ichexanthone ( 1-hydroxy-3 ,6-di methoxy-8-methylxanthone, 6 mg) m. p. and lit. [Roberts, 1961] m . p. 186-187° . A3 was chromat ographed on a dry silica column giving aliphatic ester (70 mg). lichexanthone (5 mg) and lupenone (50 mg).
TL;DR: A case of centronuclear or myotubular myopathy in a 13-year-old boy who was admitted with hypotonia and congenital ptosis is reported and the diferential diagnosis is discussed.
Abstract: E relatado um caso de miopatia miotubular ou centronuclear em paciente de 13 anos de idade, do sexo masculino, com historia de hipotonia e ptose palpebral congenitas. Estudos clinicos, eletromiograficos e anatomopatologicos (inclusive microscopia eletronica) evidenciaram achados comparaveis aos encontrados na revisao bibliografica. Sao tambem discutidos os diagnosticos diferenciais e os achados de microscopia eletronica.
TL;DR: Determinating the total protein contents by the Meulemans method and using strips of celulose acetate "Cellogel" for electrophoresis the authors have studied the CSF of 19 patients between 10 and 54 years old.
Abstract: Determinating the total protein contents by the Meulemans method and using strips of celulose acetate "Cellogel" for electrophoresis the authors have studied the CSF of 19 patients between 10 and 54 years old. Total proteins was found between 10 and 28 mg%. The proteins were separated in six fractions with the following results: pre-albumin 4.3%; albumin 54.8%; a1-globulin 5.9%; a2, globulin 8.3%; b-globulins 15.57c and d-giobulins 11.2%.
TL;DR: The study of its eggs and pupae revelaed that 80% of pupation occur in the undergrowth and 20% in the eucalyptus (14 m high), 90% of which occurred up to a height of 6 m.
Abstract: Euselasia eucerusHewitson est un ravageur de l'eucalyptus au Bresil. Certains aspects de sa biologie et de son ethologie ont ete abordes sur le terrain et au laboratoire — Une analyse de la distribution verticale des chrysalides et des pontes montre que 80% de la nymphose se fait dans le sous-bois (jusqu'a 1 m de hauteur) et que les 20% restants se fait sur les eucalyptus (de 14 m de hauteur en moyenne). De ces 20%, 90% se fixent jusqu'a 6 m de hauteur. Quant a la ponte, elle se fait sur les feuilles d'eucalyptus, avec 75% entre 2 et 8 m. 31,6% des œufs observes entre 0 et 10 m sont parasites parTrichogramma sp., ce pourcentage diminuant a 12% au-dessus de 10 m. Ce niveau eleve de parasitisme dans la nature nous suggere l'utilisation du trichogramme pour combattre ce defoliateur.
01 Dec 1977
TL;DR: In this article, the authors studied the viminol-p-hydroxybenzoate (RN: Dividol) through some psychopharmacological tests, making its comparison with neuroleptic and narcotic drugs, with the principal aim of determining if its analgesic action is correlated with a narcotic or psychotropic activity or both of them.
Abstract: The authors studied the viminol-p-hydroxybenzoate (RN: Dividol) through some psychopharmacological tests, making its comparison with neuroleptic and narcotic drugs, with the principal aim of determining if its analgesic action is correlated with a narcotic or psychotropic activity or both of them. The results are discussed.
TL;DR: Thiamphenicol injected intramuscularly in male rats 2 hours before Pentobarbital administered by the intraperitoneal route significantly increased the barbituric sleeping time as well as its half-life, and decreased its elimination rate constant.
TL;DR: In four families of color blind subjects, a dermatoglyphic analysis was made and the results compared with data from normal subjects, failing to show any significant differences in the means of the two groups.
Abstract: In four families of color blind subjects, a dermatoglyphic analysis was made and the results compared with data from normal subjects. The Student's t test, howeverf failed to show any significant differences in the means of the two groups.