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Biomedical subjects

R Arana

Publications and source records attributed to R Arana.

28 records · Page 2Linked to original sources
PubMed1980

Lymphatic tissue in Argentine hemorrhagic fever. Pathologic features.

Spleen and lymph nodes from seven fatal cases of Argentine hemorrhagic fever were studied by light and electron microscopy and by immunofluorescent techniques. In addition, Junin virus infectivity was determined. Destruction of splenic white pulp and of lymph node cortex was observed. The ultrastructural study showed a characteristic cytopathic effect on the macrophages with presence of intracisternal virus-like particles and occasional virions budding from the plasma membrane. The immunofluorescent techniques indicated the presence of Junin virus antigenic determinants in the cytoplasm of macrophages in the examined organs. Junin virus titers were three times higher than in peripheral blood. These results suggest that lymphatic tissue is one of the main sites of viral replication and that the macrophages are the targets of Junin virus.

Antigens, Viral↗
PubMed1975

Ultrastructural and immunohistochemical study of the human kidney in Argentine haemorrhagic fever.

In six lethal cases of Argentine Haemorrhagic Fever (AHF) a disease caused by Junin virus, kidney samples were studied by means of immunofluorescent and electron microscopic techniques.--The ultrastructural studies showed that the distal and collecting tubes presented a large number of virus like intracytoplasmic particles. Those particles were present in the lumen of the endoplasmic reticulum cisternae and showed two distinct morphological aspects. Some of them were of high electron density and contained a few granules. The others were larger in size, electron lucid, and contained a variable number of ribosome like granules. Both types of particles originated from the endoplasmic reticulum wall by a process of budding. The presence of these particles was coincident with a severe cell damage which lead to necrosis and desquamation; and with large quantities of Junin virus antigen as demonstrated by immunofluorescence.--On the basis of these observations it is assumed that in AHF the cell damage is due to direct viral replication within the affected cells.

Antigens, Viral↗
PubMed1967

Antibodies to native and denatured deoxyribonucleic acid in systemic lupus erythematosus.

The relative reactivities with native and denatured DNA of 35 lupus sera were investigated by quantitative complement fixation and precipitin studies and showed great variations. The use of purified native DNA demonstrated that, in at least 22 of these 35 sera, the anti-DNA antibodies reacted with the native form, independently of denatured contaminants. Systemic lupus sera were shown to contain three main types of DNA antibodies: those reacting only with denatured DNA, those reacting to the same extent with both forms of DNA, and those reacting preferentially with native DNA. In some instances, the latter antibodies fix complement and precipitate only with native DNA but are inhibited by the denatured form. This finding points to the importance of conformation in the antigenic structure of DNA. The simultaneous occurrence of different varieties of DNA antibodies was demonstrated in several sera. Evidence was obtained that some of these human antibodies to DNA can belong to the IgM class. Thus, DNA antibodies from systemic lupus patients differ in many respects from most of the experimentally produced antibodies capable of reacting with DNA.

Antibodies↗
PubMedDate not supplied

Circulating antibodies against neonatal cardiac muscarinic acetylcholine receptor in patients with Sjögren's syndrome.

Isolated congenital heart block may be associated with Primary Sjögren's Syndrome. In this work we demonstrated that IgG present in the sera of patients with Primary Sjögren's Syndrome (PSS) could bind and activate muscarinic acetylcholine receptors of rat neonatal atria. These antibodies were able to inhibit in a irreversible manner the binding of 3H-QNB to muscarinic cholinergic receptors of purified rat atria membranes. Moreover, IgG from PSS individuals could modify biological effects mediated by muscarinic cholinoceptors activation, i.e. decrease contractility and cAMP and increase phosphoinositide turnover and cGMP. Atropine blocked all of these effects and carbachol mimicked them; confirming muscarinic cholinergic receptors-mediated PSS IgG action. Neither binding nor biological effect were obtained using adult instead of neonatal rat atria. IgG from sera of normal women were not effective in the studied system. The prevalence of cholinergic antibody was 100% in PSS and was independent of Ro/SS-A and La/SS-B antibodies. It could be concluded that antibody against muscarinic cholinergic receptors may be another serum factor to be considered in the pathophysiology of the development of congenital heart block.

Adult↗
PubMedDate not supplied

Chronic experimental infection by Trypanosoma cruzi in Cebus apella monkeys.

Twenty young male Cebus apella monkeys were infected with CA1 Trypanosoma cruzi strain and reinfected with CA1 or Tulahuen T. cruzi strains, with different doses and parasite source. Subpatent parasitemia was usually demonstrated in acute and chronic phases. Patent parasitemia was evident in one monkey in the acute phase and in four of them in the chronic phase after re-inoculations with high doses of CA1 strain. Serological conversion was observed in all monkeys; titers were low, regardless of the methods used to investigate anti-T. cruzi specific antibodies. Higher titers were induced only when re-inoculations were performed with the virulent Tulahuén strain or high doses of CA1 strain. Clinical, electrocardiographic and ajmaline test evaluations did not reveal changes between infected and control monkeys. Histopathologically, cardiac lesions were always characterized by focal or multifocal mononuclear infiltrates and/or isolated fibrosis, as seen during the acute and chronic phases; neither amastigote nests nor active inflammation and fibrogenic processes characteristic of human acute and chronic myocarditis respectively, were observed. These morphological aspects more closely resemble those found in the "indeterminate phase" and contrast with the more diffuse and progressive pattern of the human chagasic chronic myocarditis. All monkeys survived and no mortality was observed.

Animals↗