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[immunologic markers of attenuation in guinea pigs infected with strains or variants of junin virus]. 19816267413
[immunologic markers of attenuation in guinea pigs infected with strains or variants of junin virus]. 19816267413
[tissue selectivity and virulence indicators of 3 strains of junin virus]. 19816268927
immunogenicity of a/ussr (h1n1) subunit vaccine in unprimed young adults.a clinical and serological study was performed on 267 of 636 volunteers vaccinated against argentine hemorrhagic fever with the xjcl3 attenuated strain of junin virus seven to nine years earlier, in order to determine their long-term evolution. this study included a clinical examination, a chest roentgenogram, an electrocardiogram, and the following laboratory determinations: white and red cell count, number of platelets, hematocrit, hemoglobin, sedimentation rate (katz index), urea, nitrogen, g ...19816270279
argentine hemorrhagic fever: a biologic marker.mortality rates and viral replication in blood and brains of wistar rats between 6 h and 26 days of age inoculated with two strains of junin virus of different virulence were compared. viral growth curves in brains showed no differences between strains. however, differences in mortality rates were significant among rats between 1 and 3 days of age. when the intracerebral (i.c.) route was used, high mortality rates were induced by the attenuated xjc13 strain and low mortality rates were induced b ...19816271705
cell-mediated immunity and lymphocyte populations in experimental argentine hemorrhagic fever (junín virus).guinea pigs infected with the xj prototype strain of junín virus reproduce the main features of argentine hemorrhagic fever, showing hemorrhages, leukothrombocytopenia, and focal lymphoid tissue necrosis. viral lymphotropism is shown by the presence of viral antigens, severe cytopathic effect, and high virus titers in lymphoid organs. a pronounced depression of humoral immune response to sheep erythrocytes as well as to the virus is described. this study was carried out to determine whether cell ...19816273314
cell-mediated immunity and lymphocyte populations in experimental argentine hemorrhagic fever (junín virus).guinea pigs infected with the xj prototype strain of junín virus reproduce the main features of argentine hemorrhagic fever, showing hemorrhages, leukothrombocytopenia, and focal lymphoid tissue necrosis. viral lymphotropism is shown by the presence of viral antigens, severe cytopathic effect, and high virus titers in lymphoid organs. a pronounced depression of humoral immune response to sheep erythrocytes as well as to the virus is described. this study was carried out to determine whether cell ...19816273314
junin virus infection of guinea pigs: immunohistochemical and ultrastructural studies of hemopoietic tissue.an association between viral antigens, cytopathic effect (cpe) and viral titers in blood and lymphoid tissues suggests a direct cpe of junin virus on the lymphopoietic organs of guinea pigs infected with 10(3) 50% lethal doses of the xj prototype strain. after seven days of infection, all lymphoreticular organs had infectivity titers higher than those for blood. virus was recovered from bone marrow and lymph nodes at day 5 after infection; peak titers were obtained from bone marrow, spleen, and ...19816260868
junin virus infection of guinea pigs: immunohistochemical and ultrastructural studies of hemopoietic tissue.an association between viral antigens, cytopathic effect (cpe) and viral titers in blood and lymphoid tissues suggests a direct cpe of junin virus on the lymphopoietic organs of guinea pigs infected with 10(3) 50% lethal doses of the xj prototype strain. after seven days of infection, all lymphoreticular organs had infectivity titers higher than those for blood. virus was recovered from bone marrow and lymph nodes at day 5 after infection; peak titers were obtained from bone marrow, spleen, and ...19816260868
[experimental infection of guinea pigs with tacaribe virus: effect on the functioning of the immunocompetent system].tacaribe virus is the member most closely related to junín virus within the tacaribe complex. it has been demonstrated that both viruses are indistinguishable by complement-fixation, due to the high cross-reactivity. however, adult guinea pigs are highly sensitive to infection with the xj pathogenic strain of junín virus whereas tacaribe virus is nonpathogenic for this species. furthermore this last virus protects them against junín virus. the xj strain reduces the immune response of guinea pigs ...19816101101
[experimental infection of guinea pigs with tacaribe virus: effect on the functioning of the immunocompetent system].tacaribe virus is the member most closely related to junín virus within the tacaribe complex. it has been demonstrated that both viruses are indistinguishable by complement-fixation, due to the high cross-reactivity. however, adult guinea pigs are highly sensitive to infection with the xj pathogenic strain of junín virus whereas tacaribe virus is nonpathogenic for this species. furthermore this last virus protects them against junín virus. the xj strain reduces the immune response of guinea pigs ...19816101101
[effect of cyclophosphamide on experimental infection of rats with 2 strains of the junin virus].the course of viral infection in rats of several ages after intracerebral inoculation with two strains of junin virus, as well as the effect of an immunosuppressor was studied. the survival rate in 2-day-old rats was 95%, which fell to 45% in cyclophosphamide-treated infected animals (figure 1a). however, barely 5% of these rats inoculated with the xjcl3 strain survived, while the cyclophosphamide suppressive treatment increased the rate to 36% (figure 1b). this contrasting behaviour suggested t ...19816101102
development of specific immune response in mice infected with junin virus.different parameters of specific immune response involved in the resistance to intracerebral junin virus (jv) infection were studied in adult balb/c mice. the relationship of virus replication to production of antiviral antibodies, to occurrence of cytotoxic t cells and to development of delayed-type hypersensitivity response was evaluated. spleen cytotoxic t cells were assayed by 51cr-release method on virus-infected h2 compatible targets. effector t cells were detected on day 2, reached peak c ...19826127015
junin virus infection of calithrix jacchus: haematological findings.haematological changes produced by experimental junin virus infection of a platyrrhine monkey, callithrix jacchus were studied. normocytic and normochromic anaemia appeared after 7 days post infection (p. i.), and increased steadily until day 21 p. i. reticulocytes and circulating erythroblasts were elevated during the anaemia, reached a peak on day 7 p. i., and disappeared later. platelets and leukocytes showed a significant decrease from days 14 and 18 p. i., respectively. these alterations co ...19826127935
junin virus infection of calithrix jacchus: haematological findings.haematological changes produced by experimental junin virus infection of a platyrrhine monkey, callithrix jacchus were studied. normocytic and normochromic anaemia appeared after 7 days post infection (p. i.), and increased steadily until day 21 p. i. reticulocytes and circulating erythroblasts were elevated during the anaemia, reached a peak on day 7 p. i., and disappeared later. platelets and leukocytes showed a significant decrease from days 14 and 18 p. i., respectively. these alterations co ...19826127935
[inhibition of the production of infectious particles in cells infected with junín virus in the presence of tunicamycin].the antibiotic tunicamycin, an inhibitor of glycoprotein synthesis, suppressed junin virus multiplication in vero cells. no infectious virus was formed if tunicamycin was added, at a concentration of 1 microgram/ml, immediately after virus adsorption and remained up to the end of the replicative cycle. tunicamycin added at 24,48 or 72 hours p.i. immediately stopped virus synthesis. the effect was irreversible. virus grown in the presence or absence of tunicamycin and labelled with 3h-uridine was ...19826101002
in vitro infection of murine macrophages with junin virus.mouse peritoneal macrophages were successfully infected with two strains of junin virus producing high titers with no apparent cell damage. infected cultures survived longer than noninfected cultures. the pattern of virus release suggested a persistent infection. virus replication was delayed in macrophages from mice previously immunized with junin virus. these results support the opinion that macrophages are targets for virus replication in vivo infections.19826274800
cross-protection in nonhuman primates against argentine hemorrhagic fever.the susceptibility of the marmoset callithrix jacchus to tacaribe virus infection was investigated to perform cross-protection studies between junin and tacaribe viruses. five marmosets inoculated with tacaribe virus failed to show any signs of disease, any alterations in erythrocyte, leukocyte, reticulocyte, and platelet counts or any changes in hematocrit or hemoglobin values. no tacaribe virus could be recovered from blood at any time postinfection. anti-tacaribe neutralizing antibodies appea ...19826276301
cross-protection in nonhuman primates against argentine hemorrhagic fever.the susceptibility of the marmoset callithrix jacchus to tacaribe virus infection was investigated to perform cross-protection studies between junin and tacaribe viruses. five marmosets inoculated with tacaribe virus failed to show any signs of disease, any alterations in erythrocyte, leukocyte, reticulocyte, and platelet counts or any changes in hematocrit or hemoglobin values. no tacaribe virus could be recovered from blood at any time postinfection. anti-tacaribe neutralizing antibodies appea ...19826276301
new attenuation marker for junin virus based on immunologic responses of guinea pigs.a new attenuation marker to distinguish a virulent strain (xjjv) from an attenuated strain (xjc13jv or xjojv) of junin virus by means of the humoral and cellular responses to unrelated antigens was studied in guinea pigs. strain xjjv suppressed the humoral immune response, as shown by the lower titers of precipitating antibody to ovalbumin. the concomitant decrease in serum complement level contributed to a milder arthus cutaneous reactivity. in contrast, the attenuated strains did not decrease ...19826278027
new attenuation marker for junin virus based on immunologic responses of guinea pigs.a new attenuation marker to distinguish a virulent strain (xjjv) from an attenuated strain (xjc13jv or xjojv) of junin virus by means of the humoral and cellular responses to unrelated antigens was studied in guinea pigs. strain xjjv suppressed the humoral immune response, as shown by the lower titers of precipitating antibody to ovalbumin. the concomitant decrease in serum complement level contributed to a milder arthus cutaneous reactivity. in contrast, the attenuated strains did not decrease ...19826278027
[infection of new world primates with junin virus: iii. saimiri sciureus]. 19826302438
[infection of new world primates with junin virus: iii. saimiri sciureus]. 19826302438
[action of cyclophosphamide on intracerebral infection of guinea pigs with junin virus]. 19826302439
[action of cyclophosphamide on intracerebral infection of guinea pigs with junin virus]. 19826302439
[prevalence of subclinical junin virus infection in a select population of an endemic area of argentinian hemorrhagic fever]. 19827132697
[response of calomys musculinus to experimental infection with junin virus]. 19826290832
[response of calomys musculinus to experimental infection with junin virus]. 19826290832
[the nursing guinea pig as an indicator of junin virus neurovirulence]. 19826306384
[the nursing guinea pig as an indicator of junin virus neurovirulence]. 19826306384
[pathology of persistent infection of calomys musculinus with an attenuated strain junin virus]. 198215170951
[pathology of persistent infection of calomys musculinus with an attenuated strain junin virus]. 198215170951
[effect of intracerebral inoculation of junin virus in guinea pigs]. 198215170953
[effect of intracerebral inoculation of junin virus in guinea pigs]. 198215170953
[effect of treatment with immune sera in rats infected with junin virus]. 198215170960
[infection of the lung with junin virus in experimental argentinian hemorrhagic fever of the guinea pig]. 19836308382
[infection of the lung with junin virus in experimental argentinian hemorrhagic fever of the guinea pig]. 19836308382
protection against a pathogenic strain of junin virus by mucosal infection with an attenuated strain.in order to determine the degree of mucosal infectivity of the attenuated xjcl3 strain of junin virus, guinea pigs were orally or nasally inoculated. infectivity was 85% for the oral and 100% for the nasal route, as detected by death or serum antibody development. the presence of serum antibodies was closely associated with resistance to challenge with the xj pathogenic strain, which killed 100% of controls when inoculated by the parenteral or nasal route. however, mortality rates after mucosal ...19836309026
protection against a pathogenic strain of junin virus by mucosal infection with an attenuated strain.in order to determine the degree of mucosal infectivity of the attenuated xjcl3 strain of junin virus, guinea pigs were orally or nasally inoculated. infectivity was 85% for the oral and 100% for the nasal route, as detected by death or serum antibody development. the presence of serum antibodies was closely associated with resistance to challenge with the xj pathogenic strain, which killed 100% of controls when inoculated by the parenteral or nasal route. however, mortality rates after mucosal ...19836309026
in vivo replication of pathogenic and attenuated strains of junin virus in different cell populations of lymphatic tissue.lymphatic tissue is one of the main sites for replication of junin virus. to characterize which cells are involved in that replication, the presence of junin virus in purified populations of macrophages and dendritic cells from the spleens of guinea pigs infected with pathogenic and attenuated strains was investigated by immunofluorescence and intracerebral inoculation into newborn mice. the pathogenic strain was present both in macrophages and in dendritic cells, but the attenuated strain selec ...19836309667
in vivo replication of pathogenic and attenuated strains of junin virus in different cell populations of lymphatic tissue.lymphatic tissue is one of the main sites for replication of junin virus. to characterize which cells are involved in that replication, the presence of junin virus in purified populations of macrophages and dendritic cells from the spleens of guinea pigs infected with pathogenic and attenuated strains was investigated by immunofluorescence and intracerebral inoculation into newborn mice. the pathogenic strain was present both in macrophages and in dendritic cells, but the attenuated strain selec ...19836309667
pathogenicity of an attenuated strain (xjcl3) of junin virus. morphological and virological studies in experimentally infected guinea pigs.infection of guinea pigs with an attenuated strain of junin virus (jv) produced 16% mortality between days 17 and 27 postinfection (p.i.). the morphological study showed a marked pancreatitis between days 6 and 23 p.i. and meningoencephalitis between days 17 and 20 p.i. in a large proportion of the animals. these lesions were coincident with the presence of jv antigenic determinants in the pancreatic acinar cells, neurons and blood vessels of the brain. infectious virus could be isolated from ly ...19836317604
pathogenicity of an attenuated strain (xjcl3) of junin virus. morphological and virological studies in experimentally infected guinea pigs.infection of guinea pigs with an attenuated strain of junin virus (jv) produced 16% mortality between days 17 and 27 postinfection (p.i.). the morphological study showed a marked pancreatitis between days 6 and 23 p.i. and meningoencephalitis between days 17 and 20 p.i. in a large proportion of the animals. these lesions were coincident with the presence of jv antigenic determinants in the pancreatic acinar cells, neurons and blood vessels of the brain. infectious virus could be isolated from ly ...19836317604
junin virus activity in two rural populations of the argentine hemorrhagic fever (ahf) endemic area.to determine the prevalence of inapparent infection with junin virus among the rural population and its relation to the clinical disease, a serological study was carried out in two zones of the endemic area of argentine hemorrhagic fever (ahf). from the first appearance of ahf in the zones (1963) and the moment of the survey (1977), 14 years had passed. a total of 695 serum samples were obtained, 540 from córdoba and 155 from buenos aires. of the 695 serum samples, 83 were positive for neutraliz ...19836317799
[chronic infection with junin virus in the rat. pathological and virological studies]. 19836318010
[viral persistence and absence of brain lesions in congenitally athymic mice infected with junin virus]. 19836318011
[different clinical manifestations of suckling mice inoculated with various strains of junin virus]. 19836325846
[neuropathology of the junin virus in the guinea pig: new contributions]. 19836325848
[neuropathology of the junin virus in the guinea pig: new contributions]. 19836325848
junin virus infection in genetically athymic mice.the progression of junin virus infection was studied in congenitally athymic mice. immunocompetent littermates were used as infected controls. as expected, the latter developed lethal encephalitis, with viremia and considerable viral replication in the brain. the mortality rate was almost 100%; the few surviving controls exhibited high serum neutralizing antibody levels and a total absence of virus in blood and brain. in contrast, nude mice did not contract the disease; all survived with persist ...19836298141
cytogenetic effect of two strains of junin virus in the guinea pig.the cytogenetic effect of two strains of junin virus on bone marrow chromosomes of the guinea pig was studied. animals infected with the attenuated strain xj-cl3 showed no differences from control animals. guinea pigs inoculated with the pathogenic strain xj exhibited a significant increase of abnormal cells, chromatid breaks, and chromosome fragments. the clastogenic ability of the xj strain is similar to the reported effect of other viruses, while the xj-cl3 strain does not appear to be clasto ...19836298143
cytogenetic effect of two strains of junin virus in the guinea pig.the cytogenetic effect of two strains of junin virus on bone marrow chromosomes of the guinea pig was studied. animals infected with the attenuated strain xj-cl3 showed no differences from control animals. guinea pigs inoculated with the pathogenic strain xj exhibited a significant increase of abnormal cells, chromatid breaks, and chromosome fragments. the clastogenic ability of the xj strain is similar to the reported effect of other viruses, while the xj-cl3 strain does not appear to be clasto ...19836298143
junin virus infection of callithrix jacchus: pathologic features.infection of callithrix jacchus, a new world primate, with the prototype strain of junin virus produced a severe disease. the animals developed multifocal hemorrhages and characteristic microscopic lesions such as meningoencephalitis, interstitial pneumonia, lymphocytic depletion of lymphatic tissue, hepatocytic necrosis, and a variable decrease in bone marrow cellularity. high virus concentrations correlated with lesions, and with the presence of viral antigenic determinants as revealed by immu ...19836301303
junin virus infection of callithrix jacchus: pathologic features.infection of callithrix jacchus, a new world primate, with the prototype strain of junin virus produced a severe disease. the animals developed multifocal hemorrhages and characteristic microscopic lesions such as meningoencephalitis, interstitial pneumonia, lymphocytic depletion of lymphatic tissue, hepatocytic necrosis, and a variable decrease in bone marrow cellularity. high virus concentrations correlated with lesions, and with the presence of viral antigenic determinants as revealed by immu ...19836301303
congenital and perinatal infection with junin virus in guinea pigs.junin virus infection in guinea pigs is known to be similar to human argentine hemorrhagic fever (ahf). the guinea pig was chosen as a model for transplacental transmission of junin virus, as both guinea pig and man have a similar placental structure. pregnant guinea pigs were infected with the pathogenic xj strain of junin virus intramuscularly route at different stages of pregnancy. the group infected during the last third of pregnancy produced 16 newborn, but mortality reached 100%: 18% were ...19836302220
congenital and perinatal infection with junin virus in guinea pigs.junin virus infection in guinea pigs is known to be similar to human argentine hemorrhagic fever (ahf). the guinea pig was chosen as a model for transplacental transmission of junin virus, as both guinea pig and man have a similar placental structure. pregnant guinea pigs were infected with the pathogenic xj strain of junin virus intramuscularly route at different stages of pregnancy. the group infected during the last third of pregnancy produced 16 newborn, but mortality reached 100%: 18% were ...19836302220
alteration of blood coagulation and complement system in neotropical primates infected with junin virus.the neotropical primate callithrix jacchus infected with junin virus presented an acute disease with hematological and neurological manifestations and died 17 to 24 days after infection. this picture is similar to that of human argentine hemorrhagic fever (ahf). blood coagulation and complement studies were performed in ten c jacchus animals inoculated with 10(3) tcid50 of junin virus, the prototype pathogenic xj strain. four monkeys were used as normal controls. infected monkeys and normal cont ...19836197506
alteration of blood coagulation and complement system in neotropical primates infected with junin virus.the neotropical primate callithrix jacchus infected with junin virus presented an acute disease with hematological and neurological manifestations and died 17 to 24 days after infection. this picture is similar to that of human argentine hemorrhagic fever (ahf). blood coagulation and complement studies were performed in ten c jacchus animals inoculated with 10(3) tcid50 of junin virus, the prototype pathogenic xj strain. four monkeys were used as normal controls. infected monkeys and normal cont ...19836197506
[persistence of junin virus in diploid human cells]. 19836664292
immunoperoxidase study of astrocytic reaction in junín virus encephalomyelitis of mice.intracerebral inoculation of strain xj clon 3 of junín virus into 1-2-day-old mice resulted in the appearance of viral antigen, detectable by means of the peroxidase antiperoxidase (pap) technique, within the cytoplasm of the neurons of the cerebral cortex, the basal nuclei, cerebellum, pons, medulla, spinal cord, and spinal ganglia; junín antigen was likewise observed, although to a lesser extent, in the cytoplasm of astrocytes. the viral antigen was found in highest concentration at the cytopl ...19836303038
[rat-junin virus model: a virulence indicator]. 19836099861
action of antithymocyte serum on junin virus infection in rats.two-day-old rats resistant to intracerebral (i.c.) infection with xj strain of junin virus (jv), were rendered sensitive to jv by treatment with antithymocyte serum (ats). the mortality reached 80%, the virus titres in brain were higher and the serum neutralizing antibodies dropped but brain lesions were absent throughout. the same host was susceptible to xjcl3 strain infection, which induced lethal encephalitis manifested by severe necrotic foci in cerebellum. ats treatment conferred significan ...19836140833
[features of infection in hamsters by junín virus].suckling hamsters infected with three low passaged strains of junin virus by intracerebral route developed a non differentiated illness with about 7 log of virus replication in the brain after which they either died between 6 and 19 days post inoculation or developed cf antibodies. even in suckling hamsters and suckling mice gave similar results for viral titration, isolation attempts were less successful in hamsters. the young hamster response was characterized by a severe neurological disease ...19836101062
[induction of heat-sensitive mutants of junín virus using 5-fluorouracil].this paper presents results concerning production, selection and isolation of conditionally lethal mutants of junin virus. two temperature sensitive (ts) mutants of junin virus, xjcl3 strain, were isolated from a virus population that had been mutagenized with 5-fluorouracil (5-fu). a study of the behaviour of wild-type virus over a range of temperature from 34 degrees c to 40 degrees c was done. in vero cells, the initial cloned junin virus stock gave very turbid plaques at 34 degrees c, more c ...19836101063
[detection of laboratory infections caused by junín virus using the neutralization and immunofluorescence technics comparatively].to study junin virus infection among laboratory workers and to compare immunofluorescence and neutralization tests, blood samples were taken from 48 individuals, of which 42 were considered high risk personnel. none of the 16 low risk workers exhibited antibodies. neutralizing antibodies were detected in 15 high risk laboratory workers. nine of the latter were already known to carry antibodies from a previous survey in 1978. titers detected were either at previous levels or slightly higher. of t ...19836101064
[development of the infection in guinea pigs infected with the attenuated variant xjo of junín virus].as previously shown, the xjo variant of junin virus (jv) is attenuated and elicits in guinea pigs a lasting humoral response and resistance to the challenge with xj pathogenic strain, during at least three months. in this paper the long term evolution of guinea pigs inoculated with xjo by im route was studied. ten animals were infected with 10(3) pfu of xjo at day 0 (group i) and an other 10, at days 0 and 77 (group ii). another 30 guinea pigs were inoculated with 10(2) pfu at day 0 (group iii) ...19836101069
[development of the infection in guinea pigs infected with the attenuated variant xjo of junín virus].as previously shown, the xjo variant of junin virus (jv) is attenuated and elicits in guinea pigs a lasting humoral response and resistance to the challenge with xj pathogenic strain, during at least three months. in this paper the long term evolution of guinea pigs inoculated with xjo by im route was studied. ten animals were infected with 10(3) pfu of xjo at day 0 (group i) and an other 10, at days 0 and 77 (group ii). another 30 guinea pigs were inoculated with 10(2) pfu at day 0 (group iii) ...19836101069
[infection of new world primates with junín virus. iv. aotus trivirgatus].owl monkeys (aotus trivirgatus) were inoculated with xj, a pathogenic strain of junin virus, seeking new animal models for argentine hemorrhagic fever. nine monkeys were inoculated intramuscularly with 30 or 300,000 tcid50 of junin virus. hematological and virological studies showed no alteration in blood elements such as red cell, reticular cell and platelets, up to 28 days after inoculation. hemoglobin and hematocrit determinations also remained constant. however, significant neutropenia was s ...19836101070
[infection of new world primates with junín virus. iv. aotus trivirgatus].owl monkeys (aotus trivirgatus) were inoculated with xj, a pathogenic strain of junin virus, seeking new animal models for argentine hemorrhagic fever. nine monkeys were inoculated intramuscularly with 30 or 300,000 tcid50 of junin virus. hematological and virological studies showed no alteration in blood elements such as red cell, reticular cell and platelets, up to 28 days after inoculation. hemoglobin and hematocrit determinations also remained constant. however, significant neutropenia was s ...19836101070
[infection in rats by the intraperitoneal route with junín virus].the susceptibility of the rat, infected at various ages by intraperitoneal route with the xj prototype strain of junin virus was studied two day-old animals showed maximum mortality, being the most suitable dose 10(3) ld50. antiviral humoral response at 35 days pi was tested in survivors of all ages. highest neutralizing antibody titers were found in those infected up to 4 days of age. this host behaves quite differently when infected by intracerebral route with the same xj strain.19836101071
[experimental infection of a south american primate, the cebus sp, with xj strain of junin virus]. 19836088938
[responsibility of serological variants in chronic junin virus infection]. 19836088939
[analysis of chromosome aberrations and sister chromatid exchanges in human lymphocyte cultures infected with junin virus (strain xj-clone 3)]. 19836088940
[lethality produced by an attenuated junin virus in suckling mice]. 19836088941
the guinea pig model for argentine hemorrhagic fever.guinea pigs infected by the peripheral route with the xj pathogenic strain of junin virus showed viscerotropism mainly in reticulo-phagocytic rich organs. by immunofluorescence, heavy infection of reticular-phagocytic cells was demonstrated, supporting the leading role of these cell types. absence of neurotropism was demonstrated by the inability to recover infectious virus, as well as the absence of antigens, immunoglobulins, or 3rd component of complement deposits, in cells, vessels, or mening ...19846095695
the guinea pig model for argentine hemorrhagic fever.guinea pigs infected by the peripheral route with the xj pathogenic strain of junin virus showed viscerotropism mainly in reticulo-phagocytic rich organs. by immunofluorescence, heavy infection of reticular-phagocytic cells was demonstrated, supporting the leading role of these cell types. absence of neurotropism was demonstrated by the inability to recover infectious virus, as well as the absence of antigens, immunoglobulins, or 3rd component of complement deposits, in cells, vessels, or mening ...19846095695
replication of junin virus in the presence of tunicamycin.in the presence of tunicamycin (tm), an antibiotic which inhibits glycosylation, junin virus-infected cells released 70% as much virus as control cultures, as measured by [35s]-methionine appearing in a sucrose gradient virus particle fraction. in this same fraction, the incorporation of [14c]-glucosamine was inhibited 85% by tm, accompanied by a dramatic decrease in the envelope glycoprotein, gp38, and a marked decrease in virus infectivity. these results indicate that the presence of gp38 on t ...19846096295
importance of dose of neutralising antibodies in treatment of argentine haemorrhagic fever with immune plasma.p6 a retrospective study outcome in patients with argentine haemorrhagic fever was associated with the amount of neutralising antibodies against junin virus present in the transfused units of immune plasma. low doses of neutralising antibodies were associated with higher mortality. a prospective study gave comparable results. a dose of no less than 3000 therapeutic units of neutralising antibodies per kg body weight is recommended. it is also suggested that the lack of effectiveness of immune pl ...19846146809
modification of junin virus neutropism in the guinea pig model.virulent and attenuated junin virus (jv) strains have been employed to study the influence of virus passage history on the neurotropism for guinea pigs. five i.p. successive passages (p1-p5) of the pathogenic jv-xj strain and of the attenuated xjo variant were performed in guinea pig spleen. viral titrations of organ suspensions were made through p1-p5 passages. the xj strain produced a widespread infection in p1 guinea pigs with viral dissemination to all organs except brain, in p5 animals the ...19846147995
modification of junin virus neutropism in the guinea pig model.virulent and attenuated junin virus (jv) strains have been employed to study the influence of virus passage history on the neurotropism for guinea pigs. five i.p. successive passages (p1-p5) of the pathogenic jv-xj strain and of the attenuated xjo variant were performed in guinea pig spleen. viral titrations of organ suspensions were made through p1-p5 passages. the xj strain produced a widespread infection in p1 guinea pigs with viral dissemination to all organs except brain, in p5 animals the ...19846147995
nasal and intrathalamic inoculations of primates with tacaribe virus: protection against argentine hemorrhagic fever and absence of neurovirulence.callithrix jacchus marmosets were inoculated by different routes with two stocks of tacaribe virus, one from suckling mouse brain and another from human diploid mrc5 cells. all 12 primates inoculated by nasal route developed neutralizing serum antibodies without any clinical signs. all 6 primates receiving the mouse brain-tacaribe virus were protected against lethal challenge with pathogenic xj strain of junin virus, while protection was also conferred in 4 out of 6 primates receiving the diploi ...19846148851
nasal and intrathalamic inoculations of primates with tacaribe virus: protection against argentine hemorrhagic fever and absence of neurovirulence.callithrix jacchus marmosets were inoculated by different routes with two stocks of tacaribe virus, one from suckling mouse brain and another from human diploid mrc5 cells. all 12 primates inoculated by nasal route developed neutralizing serum antibodies without any clinical signs. all 6 primates receiving the mouse brain-tacaribe virus were protected against lethal challenge with pathogenic xj strain of junin virus, while protection was also conferred in 4 out of 6 primates receiving the diploi ...19846148851
passive transfer protection against junin virus in cyclophosphamide-suppressed mice. 19846148861
[differentiation among strains of junín virus by intraperitoneal infection in the rat].the 2-day-old rat is known to resist intracerebral infection with the xj prototype strain of junin virus, but 95-100% mortality results when infected with the attenuated xjc13 strain. when this animal was inoculated by intraperitoneal route, behaviour was diametrically opposite: the xj strain proved lethal, while de xjc13 led to low mortality. studies on mortality, virus titer in different organs, and anti-viral humoral response in 2-day-old rats infected with junin virus strains were carried ou ...19846101033
[lack of viral persistence in 2 cebus sp].two cebus sp surviving acute junin virus infection, one after intramuscular inoculation with pathogenic xj and the other after intracerebral inoculation with xj clone 3, failed to exhibit persistent infection. although treatment with immunosuppressive drugs was carried out, no junin virus was detected in blood or organs in spite of blind passages in mice for the former as well as cocultivation with permissive vero cells for the latter. viremia was also ruled out by immunofluorescence on bhk/21 c ...19846101036
[effect of the host cells in the crossed neutralization reactions between junín and tacaribe viruses ].it has been previously reported that guinea pigs inoculated with tacaribe virus grown in suckling mouse brain, develop specific anti-junín neutralizing antibodies (na) after 45 days of infection and a typical secondary response after junín virus challenge. since in these experiments both viruses were grown in suckling mouse brain doubt was raised about the specificity of na, considering the possibility that they were raised against host-cell antigens. in order to test this interpretation the fol ...19846101038
[effect of the host cells in the crossed neutralization reactions between junín and tacaribe viruses ].it has been previously reported that guinea pigs inoculated with tacaribe virus grown in suckling mouse brain, develop specific anti-junín neutralizing antibodies (na) after 45 days of infection and a typical secondary response after junín virus challenge. since in these experiments both viruses were grown in suckling mouse brain doubt was raised about the specificity of na, considering the possibility that they were raised against host-cell antigens. in order to test this interpretation the fol ...19846101038
[effect of various schedules of cyclophosphamide administration on the mortality of the adult mouse infected with junín virus].the object of this paper was to determine the influence of cyclophosphamide immunosuppression on the mortality of 40-45 day old balb/c mice infected intracerebrally with a pathogenic strain of junin virus, using different administration schedules. up to 200 mg/kg of cyclophosphamide were not toxic. results show that, unlike in other experimental models, three or four 50 mg/kg cyclophosphamide doses given both before and after viral infection were required to break-down resistance to junin virus ...19846101041
[suckling guinea pigs as a differential indicator of the virulence of attenuated strains of junin virus]. 19846100499
[suckling guinea pigs as a differential indicator of the virulence of attenuated strains of junin virus]. 19846100499
endogenous interferon in argentine hemorrhagic fever.the induction of endogenous interferon (ifn) was studied in 28 cases of argentine hemorrhagic fever (ahf), a severe systemic disease caused by junin virus. serum samples were taken daily during the acute period, both before and after administration of immune plasma. this form of treatment has been found to reduce mortality when given early in the course of ahf. high titers of circulating ifn were present in the serum samples taken before treatment. ifn titers drastically dropped after transfusio ...19846232326
protection conferred against junin virus infection in rats.2-day-old wistar rats intracerebrally infected with the xjc13 strain of virus exhibited a 5% survival rate which rose to 71% after immune serum treatment. brain viral titers were relatively unaffected by this treatment. histologic studies showed necrosis in the cerebellum and brain cortex with mononuclear cell infiltration in both treated and nontreated groups. beginning on day 16 postinfection, however, intracerebral perivascular gliosis foci and mild meningeal congestion were minimal in the tr ...19846327562
transplacental infection in guinea pigs inoculated with an attenuated strain of junin virus.transplacental infection by the attenuated xjc13 strain of junin virus (jv) in the guinea pig model was evaluated. 5 pregnant guinea pigs were infected intramuscularly at 45 +/- 3 days of pregnancy. 4 animals were killed at 14 days postinfection (p.i.), and 1 was sacrificed at 137 days p.i. at the end of its second pregnancy. evidence of jv was obtained by vero cell cocultivation in all 14 fetuses harvested (brain and/or spleen) and in 10 of 11 placentas. the results strongly suggest that the at ...19846327563
transplacental infection in guinea pigs inoculated with an attenuated strain of junin virus.transplacental infection by the attenuated xjc13 strain of junin virus (jv) in the guinea pig model was evaluated. 5 pregnant guinea pigs were infected intramuscularly at 45 +/- 3 days of pregnancy. 4 animals were killed at 14 days postinfection (p.i.), and 1 was sacrificed at 137 days p.i. at the end of its second pregnancy. evidence of jv was obtained by vero cell cocultivation in all 14 fetuses harvested (brain and/or spleen) and in 10 of 11 placentas. the results strongly suggest that the at ...19846327563
persistence of attenuated junin virus strains in guinea pigs infected by im or ic routes. 19846330233
persistence of attenuated junin virus strains in guinea pigs infected by im or ic routes. 19846330233
[in vivo inhibition of t lymphocyte dth in encephalitis produced by junin virus]. 19853879861
polypeptide synthesis in junín virus-infected bhk-21 cells.analysis by immune precipitation and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page) of intracellular [35s]-methionine-labelled specific junín virus polypeptides demonstrated synthesis of the nucleoprotein (np64) between 24 to 96 hr post-infection (p.i.). two glycoproteins with apparent molecular weights (mr) of 72,000 (gp72) and 38,000 (gp38) were detected by pulse labelling with [35s]-methionine or sugar precursor at about 48 hr p.i. the rate of synthesis of gp38 increase ...19852860803
infection of cebus monkeys with junín virus. 19853020338
[inactivated junin virus antigens]. 19853020339
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