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21.
ABSTRACT: A Male rabbit was immunized with rat testicular cytochrome (Cyt) ct and mated with normal, unimmunized females. The matings resulted in abnormal pregnancies: no offspring or stillborn or undersized liveborn offspring weighing 25–30 gm each. Another unusual observation was that fur-pulling behavior, normally exhibited by pregnant female rabbits at the end of the gestational period, was absent in all of these pregnancies. Therefore, immunization of a normal rabbit with testicular cyt ct appeared to interfere with physiological and behavioral aspects of pregnancy in normal female rabbits. The immunological basis of these findings remains to be determined. 相似文献
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Meyer-Fernandes JR Saad-Nehme J Peres-Sampaio CE Belmont-Firpo R Bisaggio DF Do Couto LC Fonseca De Souza AL Lopes AH Souto-Padrón T 《Parasitology research》2004,93(1):41-50
In this work, we describe the ability of living epimastigotes of Trypanosoma cruzi to hydrolyze extracellular ATP. In these intact parasites, there was a low level of ATP hydrolysis in the absence of any divalent metal (2.42±0.31 nmol Pi/h×108 cells). ATP hydrolysis was stimulated by MgCl2, and the Mg-dependent ecto-ATPase activity was 27.15±2.91 nmol Pi/h×108 cells. The addition of MgCl2 to the extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. This stimulatory activity was also observed when MgCl2 was replaced by MnCl2, but not by CaCl2 or SrCl2. The apparent Km for Mg-ATP2– was 0.61 mM, and free Mg2+ did not increase the ecto-ATPase activity. This ecto-ATPase activity was insensitive to the inhibitors of other ATPase and phosphatase activities. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, DIDS (4, 4.diisothiocyanostylbene 2-2-disulfonic acid) as well as suramin, an antagonist of P2 purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg2+-dependent ATPase activity in a dose-dependent manner. A comparison among the Mg2+-ecto-ATPase activities of the three forms of T. cruzi showed that the noninfective epimastigotes were less efficient at hydrolyzing ATP than the infective trypomastigote and amastigote stages. 相似文献
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Survey of rotavirus G and P types associated with human gastroenteritis in São Paulo, Brazil, from 1986 to 1992.
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Rotavirus strains causing gastroenteritis in Brazilian children were characterized by PCR-based typing assays. In addition to strains bearing the major human G and P types, large numbers of strains bearing P3 (M37-like), P6 (HCR3-like), untypeable P and G types, and complex mixtures of P and G types not previously recognized were present in the community. 相似文献
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Rubem Carlos Araujo Guedes Romualdo José do Carmo 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1980,39(3):341-349
Summary The ionic composition of the internal environment was altered in rabbits by means of gastric washing, combined with intramuscular administration of 3-Beta-aminoethylpyrazole. The effects of this treatment on cortical spreading depression (SD) were studied. C1- and Na+ concentrations decreased significantly in serum and in cerebrospinal fluid after the treatment. This made the animals much more susceptible to SD, as established by the high incidence of spontaneous SD, increased SD velocity of propagation and facilitated its interhemispheric transfer. An intensification of the epileptiform activity associated with SD was also observed. Intravenous replacement of NaCl abolished the above effects on SD. When the intravenous replacement was done with Na-Isethionate, those effects were enhanced. It is concluded that chloride deficiency was the main factor responsible for the observed facilitating effects.This work was supported by grants from the BNDE (FUNTEC-74 e 143), CNPq and CAPES 相似文献
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Calabrese KS Paradela AS do Valle TZ Tedesco RC Leonardo R Mortara RA Gonçalves da Costa SC 《Pathologie-biologie》2003,51(3):129-134
In this article, we have characterized cell subpopulations found in the hearts of mice presenting acute Chagas' disease by immunocytochemistry and subjected to different schedules of an immunosuppressive therapy with cyclophosphamide (CY). In this comparative study, CY treatment with different doses was carried out before or after infection with Trypanosoma cruzi Y strain trypomastigotes, enabling us to discriminate the parasitemic kinetics and inflammatory processes in the heart, 12 d after infection. Animals treated with 200 mg/kg of CY 2 d before infection presented high parasitaemia as well as heavy inflammation and low parasite loads in the heart. Mice treated 5 d after infection with the same dose, developed the same parasitaemic peak but were not able to control it. Their heart did not present inflammation, but a high number of parasites could be seen. Animals treated with five 3 mg/kg doses of CY every other day presented heavy inflammatory reaction and low parasitaemia. In this group, as well as the one treated before infection, immunocytochemistry studies have shown predominance of CD8(+) T cells in the myocardium. On the other hand, mice treated with 200 mg/kg of CY 5 d after infection, presented small amounts of CD4(+) T cells while no CD8(+) could be found. These results have confirmed the dose dependence influence of this drug on the T cell populations in the inflammatory infiltrates as well as the importance of the schedule employed. 相似文献
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H. REIJONEN S. NEJENTSEV J. TUOKKO S. KOSKINEN E. TUOMILEHTO-WOLF H. K. KERBLOM J. ILONEN THE CHILDHOOD DIABETES IN FINLAND STUDY GROUP 《International journal of immunogenetics》1997,24(5):357-363
We determined the distribution of DR4 subtypes in 309 DQB1*0302-positive haplotypes found in insulin-dependent diabetes mellitus (IDDM) patients and 70 control haplotypes present only in healthy family members. An increased frequency of DRB1*0401 allele (74.4% vs. 55.7%, P = 0.003) and a decrease of DRB1*0404 allele (23.6% vs. 40.0%, P = 0.0064) was revealed. A further analysis of extended haplotypes demonstrated strong linkages between various B alleles and DRB1*04 subtypes. HLA-B39 was more frequent in DRB1*0404–DQB1*0302-positive IDDM haplotypes compared with control ones (37.0% vs. 14.3%, P = 0.049), suggesting an involvement of the region telomeric to HLA-DRB1 in the susceptibility to IDDM. 相似文献