Skin morphology of the mutant hairless USP mouse

The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.

Two related thrombin-like enzymes present in Bothrops atrox venom

This article describes the presence of two new forms of a thrombin-like enzyme, both with apparent molecular masses of 38 kDa, in Bothrops atrox venom. Both share the ability to cleave fibrinogen into fibrin and to digest casein. Both present identical Km on the substrate BApNA. Their N-terminal amino acid sequences are identical for 26 residues, sharing 80 percent homology with batroxobin and flavoxobin. Two groups of monoclonal antibodies (mAbs) raised against the purified enzyme forms recognized different epitopes of the putative corresponding enzymes present in B. atrox crude venom. On Western blotting analysis of B. atrox crude venom, mAbs 5DB2C8, 5AA10 and 5CF11, but not mAbs 6CC5 and 6AD2-G5, revealed two or more protein bands ranging from 25 to 38 kDa. By immunoprecipitation assays, the 6AD2-G5 mAb was able to precipitate protein bands of 36-38 kDa from B. atrox, B. leucurus, B. pradoi, B. moojeni, B. jararaca and B. neuwiedii crude venoms. Fibrinogen-clotting activity was inhibited when the same venom specimens were pre-incubated with mAb 6AD2-G5, except for B. jararaca and B. neuwiedii

A new mutant hairless mouse with limph node hyperplasia and late onset of autoimmune pathology

Adult BALB/c male mice were injected with a single dose of ethyl nitroso urea (ENU; 250 mg/Kg, ip) and mated to C57BL/6, DBA/2 AND A/J adult females 13 weeks later. F1 males were mated with BALB/c females and F2 females were then backcrossed to the F1 parents. One BALB/c male mouse thus teated gave origin to a mutant presenting hair and skin alterations similar to those of natural hairless mutants. The new mutation is located on chromosome 14 near the Es10 locus, and probably at the same locus for the hairless mutation. Similar to the hairless mouse, this new mutant has a normal phenotype at birth and after three weeks starts to loose hair which is never replaced. Additionally, the skin becomes thickened and wrinkled. One feature that distinguishes this mutant from other hairless mice is the peculiar enlargement of its axillary and cervical lymph nodes. The new mutant develops membranoproliferative glomerulonephritis similar to the rhino mouse, one of the hariless allele mutants already described in the literature, but with a much later onset

The complement system of calomys callosus, rengger, 1830 (Rodentia, Cricettidae)

The complement system (C) of Calomys callosus, rengger, 1830 (Rodentia, Cricetidae) a wild reservoir for several infectious agents in Latin America, was characterized. Sera from normal adult animals lysed sheep erythrocytes (Es) previouusly sensitized with rabbit serum antii-Es (Ar) in the presence of veronal-buffered saline containing 0.15 mM CaCl2 and 0.5 mM MgCl2, pH 7.4, or unsensitized rabbit erythrocytes (Er) in the presence of one-half isotonic strength veronal-buffered-saline containing 2.5% glucose, 2mM MgCl2 and 10 mM EGTA, pH 7.4. Both hemolytic curves were sigmoidal in shape, withh CH50 values of 30-40 for females and 20-30 for males. C5, determined hemolytically using the intermediate cells EsArClm4m2m3m, was approximately 4.5 x 10 8/ml and 4.0 x 10 8/ml for females and males, respectivelyy. Immunochemical serum analyses by double immunodiffusion or by immunoblotting using polyclonal antisera against human C1s, C1q, C2, C3, C4, C5, C8 and factors B, I and H indicated that C. callosus was found to contain effective classical and alternative pathways (CP, AP) and common pathways, reasonable amounts of C5 and common epitopes in the key C components, factor B, C4 and C3, which were preserved during evolution

Evasion of Trypanosoma cruzi from complement lysis

This review outlines: a) the main biochemical and biological properties of the complement system (C) componentes; b) the manner through which they interact in the two distinct routes of C activation, the classical and the alternative pathways, to generate the enzymes C3 and C5 convertases responsible for release of the peptides C4a, C3a and C5a endowed with the properties of mediating the early events of the inflammatory process or the potentially cytolytic complex C5b-C9; c) the main features of control of these activation processes; d) the identification of cell surface components present in the trypomastigote forms of Trypanosoma cruzi possibly involved in the mechanisms developed by this parasite to evade C lysis; e) the inactivation or removal of these cell surface components by enzymatic (trypsin or papin), chemical (periodate) or physical (heating at 45-C) treatments; f) isolation of these components by chromatographic methods; and, g) demonstration that some of these cell surace components interfere with C3 convertase formation or action in a manner similar to the decay accelerating factor (DAF)

Estudo imunobiológico de estoques de Trypanosoma cruzi isolados de pacientes na fase aguda da doença de Chagas

Estoques de tripanossomas isolados de pacientes na fase aguda da doença de Chagas foram injetados em grupos de camundongos albinos não isogênicos nas doses de 10³, 10(4) e 10(5) parasitas/camundongos. O curso da infecção foi seguido por três meses. A pctrasitemia foi em geral baixa, com picos recorrentes, na maioria das vezes os animais evoluiam para cronicidade. Somente um estoque induziu alto índice de mortalidade. Os parasitas e as lesões apesar de detectadas no pico da parasitemia e restritos ao coração estavam ausentes aos três meses. Nesta época os perfis de Igs apresentaram diferenças marcantes. Grupos de animais que foram inoculados com estes estoques foram desafiados com doses letais da cepa Y ou CL. Em alguns casos obteve-se uma parasitemia, mas patente.

Ten stocks of trypanosomes isolated from patients at the acute phase of Chagas'disease were injected into groups of outbred normal mice at the doses of 10³, 10(4) and 10s5 parasites/mouse and the course of the infections followed up for 3 months. The parasitemia was usually low, with recurrent peaks, the animals evolving to chronicity, only one of them inducing high ratio of mortality. Pattems of parasitemia and mortality were essentially different for each stock studied; only one stock did show similar pattems to well known strains (Yand CL) commonly used in experimental work. Parasites and lesions, although detected at the peak of parasitemia and restricted to heart were absent after three months. At this period the Igs profiles showed striking differences with respect to their distribution. Groups of mice that had been inoculated with one of the stocks were challenged with the Y or CL strains. In some instances low parasitemias although patent were seen after the infecting dose.