Publications

[vero cells persistently infected with junin virus. i. behavior of the vero ir 58 cell line after superinfection with 2 strains of junin virus].		1972	4559344
the brains of suckling mice infected with junin virus; fractionation and study.		1972	4509283
[protein synthesis and formation of junin virus in bhk cells].		1974	4424508
ultrastructure of junín virus in mouse whole brain and mouse brain tissue cultures.	comparative ultrastructural studies were performed on the development of junín virus in mouse brain and in cerebellum explants and brain monolayers of the same animal. in mouse brain, neurons and astrocytes released virus particles by a budding mechanism identical to that previously described for this virus. in the neurons, the viral multiplication took place in the perikarion as well as in the cytoplasmic processes, including areas near synapses. viral particles were observed emerging from peri ...	1974	4417948
phytohaemagglutinin unresponsiveness in leukopenia induced by junin virus in guinea pigs.		1972	4402253
phytohaemagglutinin unresponsiveness in leukopenia induced by junin virus in guinea pigs.		1972	4402253
nutritional requirements for junin virus production in bhk culture cells.		1974	4377723
[analysis of factors conditioning plaque formation in vero cells infected with tacaribe and junin virus (fha)].		1974	4377464
[purification of junin virus from the brain of infected mice].		1969	4259112
[changes in lipids in the blood of guinea pigs infected with junin virus].		1969	4259111
[changes in lipids in the blood of guinea pigs infected with junin virus].		1969	4259111
[dimensions of the junin virus (argentine hemorrhagic fever)].		1969	4241369
[electrolyte modifications of the plasma of guinea pigs infected by junin virus].		1968	4238205
[electrolyte modifications of the plasma of guinea pigs infected by junin virus].		1968	4238205
[antigenic relations among 7 strains of junin virus isolated during epidemics of several years].		1967	4229417
junín virus.		1974	4213994
immunosuppression by junin virus. ultrastructural study.		1974	4213176
endotoxin-induced protection against experimental junín virus infection.		1973	4199435
[in vivo inhibition of t lymphocyte dth in encephalitis produced by junin virus].		1985	3879861
effect of actinomycin d on arenavirus growth and estimation of the generation time for a virus particle.	in an attempt to define the involvement of host transcription in arenavirus growth, a study was made of the effect of actinomycin d (amd) on the yields of infectious pichinde, tacaribe and junin viruses. the drug was added either immediately after virus adsorption or later after infection, at the stationary phase of virus growth. the time of exposure of the infected cells to the inhibitor was so chosen that the generation and release of virus into the medium took place in the presence of amd. a ...	1986	3765824
geographic patterns of allele frequencies in calomys musculinus reservoir-host of junin virus.		1986	3543610
geographic patterns of allele frequencies in calomys musculinus reservoir-host of junin virus.		1986	3543610
mouse splenocyte transfer effect depends on donor's junin virus infection stage.	splenocytes from junin-virus-persistently-infected euthymic mice taken at 45 days postinfection seemed unable to induce overt signs of disease, to cause death, or to modify brain viral levels when transferred to athymic junin-virus-infected mice. findings differed sharply when the same recipients were transferred with splenocytes taken at 6 or 30 days postinfection from immunocompetent mice infected in adult life, since mortality reached 80 or 50%, respectively, and brain viral titers were signi ...	1988	3260227
effect of polymorphonuclear depletion on experimental argentine hemorrhagic fever in guinea pigs.	the role that polymorphonuclear leukocytes (pmn) may play in argentine hemorrhagic fever (ahf), an endemo-epidemic disease caused by junín virus (jv), was investigated in experimentally infected guinea pigs depleted of pmn by means of specific antiserum. in leucopenic animals the evolution of the infection with a highly pathogenic strain of jv was more severe, with earlier mortality and higher virus yields in blood and viscera. the pathological study showed similar lesions in both the control an ...	1987	3040897
effect of polymorphonuclear depletion on experimental argentine hemorrhagic fever in guinea pigs.	the role that polymorphonuclear leukocytes (pmn) may play in argentine hemorrhagic fever (ahf), an endemo-epidemic disease caused by junín virus (jv), was investigated in experimentally infected guinea pigs depleted of pmn by means of specific antiserum. in leucopenic animals the evolution of the infection with a highly pathogenic strain of jv was more severe, with earlier mortality and higher virus yields in blood and viscera. the pathological study showed similar lesions in both the control an ...	1987	3040897
experimental argentine hemorrhagic fever in rhesus macaques: virus-specific variations in pathology.	two isolates of junin virus (espindola and ledesma) inoculated into rhesus macaques produced distinct lesions which were strain-constant and similar to reported human cases of argentine hemorrhagic fever. the espindola isolate was associated with hemorrhagia, necrosis of bone marrow, and mild hepatocellular necrosis. ledesma isolate was associated with pronounced polioencephalomyelitis and autonomic ganglioneuritis, but very mild or absent hepatocellular necrosis, bone marrow necrosis, and hemor ...	1987	3039051
experimental argentine hemorrhagic fever in rhesus macaques: virus-specific variations in pathology.	two isolates of junin virus (espindola and ledesma) inoculated into rhesus macaques produced distinct lesions which were strain-constant and similar to reported human cases of argentine hemorrhagic fever. the espindola isolate was associated with hemorrhagia, necrosis of bone marrow, and mild hepatocellular necrosis. ledesma isolate was associated with pronounced polioencephalomyelitis and autonomic ganglioneuritis, but very mild or absent hepatocellular necrosis, bone marrow necrosis, and hemor ...	1987	3039051
intracerebral infection of cebus apella with the xj-clone 3 strain of junín virus.	to assess the usefulness of the south american primate cebus apella as a model for neurovirulence of junín virus, eight monkeys were inoculated with 10(5) ld50 of the attenuated xj-clone 3 junín virus strain by the intrathalamic route. after the second week, weight loss and polyadenopathies were observed in most animals, one-half of which had a transient leukothrombocytopenia. moderate clinical central nervous system (cns) involvement was present in four of eight monkeys, while the rest had only ...	1987	3031201
intracerebral infection of cebus apella with the xj-clone 3 strain of junín virus.	to assess the usefulness of the south american primate cebus apella as a model for neurovirulence of junín virus, eight monkeys were inoculated with 10(5) ld50 of the attenuated xj-clone 3 junín virus strain by the intrathalamic route. after the second week, weight loss and polyadenopathies were observed in most animals, one-half of which had a transient leukothrombocytopenia. moderate clinical central nervous system (cns) involvement was present in four of eight monkeys, while the rest had only ...	1987	3031201
in vitro induction of human polymorphonuclear leukocyte damage by junin virus.		1986	3027495
modification of junin virus neurotropism in mice by selective brain or spinal cord passaging.	the percentage of suckling mice that developed paralysis after intracerebral junin virus (xj-jv pathogenic strain) inoculation (13.8%) consistently increased after 5 serial passages of virus-infected brain or spinal cord obtained from paralytic animals, reaching 37.9 and 45.7%, respectively. as expected, all paralytic mice exhibited an identical spinal cord histologic picture, with widespread jv antigen in spinal cord astrocytes and neurons, particularly the large motor neurons of the anterior h ...	1986	3026992
induction of junin virus persistence in adult athymic mice.	to determine the role of t lymphocytes in adult mice infected with junin virus, 60-day-old athymic (nu/nu) mice and their immunocompetent (nu/+) littermates were inoculated intracerebrally with 10(3) tcd50 of the xj strain. none of them exhibited neurologic illness during a 6-month observation period, and mortality was 3% for nu/nu and 7% for nu/+ animals. the main features in infected nu/nu mice were: high viral titers in brain, reaching a late peak (6.5 log/ml) 32 days postinoculation and pers ...	1986	3026991
experimental argentine hemorrhagic fever: myocardial involvement in cebus monkey.	four cebus apella monkeys, to test a recently proposed model for testing neurovirulence of junín virus (jv) strains, were intracerebrally infected with 10(5) ld50 of the xj clone 3 strain of jv. there were no significant electrocardiographic abnormalities or gross lesions, but all infected monkeys exhibited a varying degree of histologic myocardial lesions including focal lymphoblastic infiltrates, vascular ruptures, and mild interstitial reactive change. one cebus showed lymphocytic infiltrates ...	1986	3025446
experimental argentine hemorrhagic fever: myocardial involvement in cebus monkey.	four cebus apella monkeys, to test a recently proposed model for testing neurovirulence of junín virus (jv) strains, were intracerebrally infected with 10(5) ld50 of the xj clone 3 strain of jv. there were no significant electrocardiographic abnormalities or gross lesions, but all infected monkeys exhibited a varying degree of histologic myocardial lesions including focal lymphoblastic infiltrates, vascular ruptures, and mild interstitial reactive change. one cebus showed lymphocytic infiltrates ...	1986	3025446
protection of junín virus-infected marmosets by passive administration of immune serum: association with late neurologic signs.	argentine hemorrhagic fever (junín virus) is a human viral disease for which immune therapy proves effective, though a late neurologic syndrome is occasionally associated with the treatment. we attempted to determine in the infected marmoset callithrix jacchus whether immune therapy leads to protection and/or cns damage. fifteen c jacchus were inoculated with 10(3) tissue culture infectious dose 50% (tcid50) of the xj strain of junín virus. on day 6 post infection (pi), 12 primates were treated ...	1987	3025358
protection of junín virus-infected marmosets by passive administration of immune serum: association with late neurologic signs.	argentine hemorrhagic fever (junín virus) is a human viral disease for which immune therapy proves effective, though a late neurologic syndrome is occasionally associated with the treatment. we attempted to determine in the infected marmoset callithrix jacchus whether immune therapy leads to protection and/or cns damage. fifteen c jacchus were inoculated with 10(3) tissue culture infectious dose 50% (tcid50) of the xj strain of junín virus. on day 6 post infection (pi), 12 primates were treated ...	1987	3025358
[modification of the course of junin virus infection in guinea pigs by administration of immune sera].		1985	3023791
[modification of the course of junin virus infection in guinea pigs by administration of immune sera].		1985	3023791
[mononuclear phagocytes in the resistance of mice to extraneural infection with junin virus].		1985	3023788
therapeutic effect of the antiviral agent ribavirin in junín virus infection of primates.	in order to assess the effect of the antiviral ribavirin on the course of junín virus infection in callithrix jacchus, seven inoculated monkeys were treated with 15 mg of the drug, twice a day, starting 6 days after infection when all animals were viremic. the three untreated controls showed typical signs of junín virus infection at 14 days pi and their mean time of death was 18 days. in contrast, no signs of illness were detected in ribavirin-treated animals until 24 days pi, when marmosets sho ...	1986	3023541
therapeutic effect of the antiviral agent ribavirin in junín virus infection of primates.	in order to assess the effect of the antiviral ribavirin on the course of junín virus infection in callithrix jacchus, seven inoculated monkeys were treated with 15 mg of the drug, twice a day, starting 6 days after infection when all animals were viremic. the three untreated controls showed typical signs of junín virus infection at 14 days pi and their mean time of death was 18 days. in contrast, no signs of illness were detected in ribavirin-treated animals until 24 days pi, when marmosets sho ...	1986	3023541
treatment of junin virus-infected guinea pigs with immune serum: development of late neurological disease.	guinea pigs infected with argentine hemorrhagic fever virus (junin) were treated with pooled, homologous convalescent sera. use of 15,000 or 5,000 therapeutic units of immune sera prevented all signs of illness when administered within 24 hr of infection. we could also prevent illness and death in infected guinea pigs as late as 6 days after infection if we used more antisera (30,000 therapeutic units/kg). in some treatment groups, surviving animals developed a late neurological syndrome with pr ...	1986	3023540
treatment of junin virus-infected guinea pigs with immune serum: development of late neurological disease.	guinea pigs infected with argentine hemorrhagic fever virus (junin) were treated with pooled, homologous convalescent sera. use of 15,000 or 5,000 therapeutic units of immune sera prevented all signs of illness when administered within 24 hr of infection. we could also prevent illness and death in infected guinea pigs as late as 6 days after infection if we used more antisera (30,000 therapeutic units/kg). in some treatment groups, surviving animals developed a late neurological syndrome with pr ...	1986	3023540
[effect of cyclophosphamide on the development of infection in calomys musculinus with junin virus].		1985	3022105
[effect of cyclophosphamide on the development of infection in calomys musculinus with junin virus].		1985	3022105
[junin virus activity in humans and rodents of non-endemic areas of the province of buenos aires].		1985	3020341
[inactivated junin virus antigens].		1985	3020339
infection of cebus monkeys with junín virus.		1985	3020338
chronic neurologic disease in junín virus-infected rats.	the purpose of this study was to determine whether junín virus persistence in cns of rats was capable of inducing late neurologic disease. following intracerebral inoculation of newborn animals with xj strain, three distinct stages could be discerned: an early phase of acute disease, up to 30 days pi, with 5% mortality; an intermediate one, extending to 280 days pi, without clinical signs but with evident viral persistence; and a final period of chronic illness, featuring clinical neurologic syn ...	1986	3020168
partial characterization of two temperature-sensitive mutants of junin virus.	two temperature sensitive (ts) mutants of junin virus, a member of arenaviridae, have been partially characterized. both mutants, named ts-32 and ts-40, had a relative plating efficiency 40 degrees c/34 degrees c lower than 10(-3) an exhibited a leak yield below 10(-4). standard growth curves showed that at 34 degrees c the viral mutants multiplied slower than wt virus and at high multiplicity did not display autointerference. no differences in thermolability were observed between wt and ts muta ...	1986	3018452
macrophage maturity and modulation of response to junín virus in infected rats.	replication of junín virus in peritoneal macrophages from newborn rats was greater for prototype strain xj than for strain xjc13, whereas in cells from adult animals viral multiplication proved minimal. transfer of peritoneal adherent cells from normal adult to strain xj-infected newborn rats lowered mortality significantly. silica blockade of macrophages protected two-day-old strain xj-infected animals and depressed brain titers of virus significantly, whereas treatment had no effect on strain ...	1986	3016114
antigenic variants of junín virus isolated from infected calomys musculinus. brief report.	junín virus establishes a long-term persistent infection in its natural host, calomys musculinus. virus recovered from blood of infected animals from 14 to 61 days p.i. behaved antigenically distinct to parental virus, as shown by cross neutralization assays. the emergence of antigenic viral variants occurs during both the acute and persistent state of infection.	1986	3015087
antigenic variants of junín virus isolated from infected calomys musculinus. brief report.	junín virus establishes a long-term persistent infection in its natural host, calomys musculinus. virus recovered from blood of infected animals from 14 to 61 days p.i. behaved antigenically distinct to parental virus, as shown by cross neutralization assays. the emergence of antigenic viral variants occurs during both the acute and persistent state of infection.	1986	3015087
photodynamic inactivation of junin virus.		1986	3014294
effect of ribavirin and immune serum on junin virus-infected primates.		1986	3014292
damage of human polymorphonuclear leukocytes by junin virus.		1986	3014291
heterogeneity of junin virus strains.		1986	3014289
relationship between junin virus infection of thymus and the establishment of persistence in rodents.		1986	3014287
junin virus isolation from lympho-mononuclear cells of patients with argentine hemorrhagic fever.	detection of viremia was attempted by three different methods in 30 cases of argentine hemorrhagic fever (ahf). cocultivation of peripheral blood mononuclear cells (pbmc) with vero cell monolayers was the most sensitive, detecting junin virus (jv) in 96% of the cases. inoculation of whole blood into suckling mice and on vero cells rendered 53 and 46% of positive isolations, respectively. the results presented suggest that pbmc are infected with jv during the acute period of ahf. jv was isolated ...	1986	3013799
effect of ribavirin and tributylribavirin on argentine hemorrhagic fever (junin virus) in guinea pigs.	subcutaneous injections of ribavirin into guinea pigs infected intraperitoneally or intracerebrally with junin virus significantly increased the mean time to death but did not enhance survival of the animals. we found similar results with tributylribavirin. virus replication was delayed, but not prevented, in ribavirin-treated infected guinea pigs. the animals usually died with high virus titers in their brains and frequently were paralyzed.	1986	3013087
effect of ribavirin and tributylribavirin on argentine hemorrhagic fever (junin virus) in guinea pigs.	subcutaneous injections of ribavirin into guinea pigs infected intraperitoneally or intracerebrally with junin virus significantly increased the mean time to death but did not enhance survival of the animals. we found similar results with tributylribavirin. virus replication was delayed, but not prevented, in ribavirin-treated infected guinea pigs. the animals usually died with high virus titers in their brains and frequently were paralyzed.	1986	3013087
junin virus access to cns by extraneural rat inoculation.	this study was carried out to determine the pathways along which two strains of junin virus (jv), the pathogenic xjv and the attenuated xjc13v, reach the cns following ip inoculation of 2-day-old rats. a sequential study of infectivity and antigen distribution in peritoneal macrophages, spleen, and brain was performed. mortality was 85% with the former strain, but only 15% with the latter. at 4-7 days pi, xjv-infected animals had viral antigen in 10% of peritoneal macrophages. viremia and spleen ...	1986	3009706
experimental infection of akodon molinae (rodentia, cricetidae) with junín virus.	experimental infection with the xj-clone 3 strain of junín virus in laboratory bred akodon molinae, a cricetid rodent inhabiting the borders of endemic argentine hemorrhagic fever areas, was studied. suckling animals inoculated intracerebrally proved sensitive and became chronically infected. sixty percent of the rodents showed neurologic involvement, with mortality reaching 60%. virus was recovered from the brain at 7, 15, 21, 37, and 57 days postinfection (pi). by immunofluorescence (if), vira ...	1986	3009705
experimental infection of akodon molinae (rodentia, cricetidae) with junín virus.	experimental infection with the xj-clone 3 strain of junín virus in laboratory bred akodon molinae, a cricetid rodent inhabiting the borders of endemic argentine hemorrhagic fever areas, was studied. suckling animals inoculated intracerebrally proved sensitive and became chronically infected. sixty percent of the rodents showed neurologic involvement, with mortality reaching 60%. virus was recovered from the brain at 7, 15, 21, 37, and 57 days postinfection (pi). by immunofluorescence (if), vira ...	1986	3009705
role of calomys musculinus peritoneal macrophages in age-related resistance to junin virus infection.	in nature, the cricetid calomys musculinus is the principal host of junin virus, the etiological agent of argentine hemorrhagic fever. in the experimental infection, adult c. musculinus survived whereas newborns died after intraperitoneal inoculation with the xj.cl3 strain of junin virus. the role of peritoneal macrophages in this age-related resistance was studied. junin virus multiplied in cultivated macrophages from either neonatal or adult animals and, therefore, it was not possible to corre ...	1986	3009700
role of calomys musculinus peritoneal macrophages in age-related resistance to junin virus infection.	in nature, the cricetid calomys musculinus is the principal host of junin virus, the etiological agent of argentine hemorrhagic fever. in the experimental infection, adult c. musculinus survived whereas newborns died after intraperitoneal inoculation with the xj.cl3 strain of junin virus. the role of peritoneal macrophages in this age-related resistance was studied. junin virus multiplied in cultivated macrophages from either neonatal or adult animals and, therefore, it was not possible to corre ...	1986	3009700
administration of antithymocyte serum modifies the response of calomys musculinus to junin virus infection.	approximately 80% of calomys musculinus inoculated with an attenuated strain of junin virus (jv) developed a lethal encephalitis. antithymocyte serum, a potent suppressor of t-cell-mediated immunity, was studied for its effect on jv pathogenicity. early administration of an anti-c. musculinus thymocyte serum (acts) to neonatal animals significantly diminished clinical disease and death and abrogated brain damage, which is usually associated with viral presence in the brain. late acts administrat ...	1986	3009353
administration of antithymocyte serum modifies the response of calomys musculinus to junin virus infection.	approximately 80% of calomys musculinus inoculated with an attenuated strain of junin virus (jv) developed a lethal encephalitis. antithymocyte serum, a potent suppressor of t-cell-mediated immunity, was studied for its effect on jv pathogenicity. early administration of an anti-c. musculinus thymocyte serum (acts) to neonatal animals significantly diminished clinical disease and death and abrogated brain damage, which is usually associated with viral presence in the brain. late acts administrat ...	1986	3009353
brain inflammatory exudate in junin virus-infected rats: its characterization by the immunoperoxidase (pap) technique.	morphologic changes in cyclophosphamide (cy)-suppressed vs. control non-suppressed new-born rats infected i.c. with xjc13 strain of junin virus were compared and the cells involved in cns lesions were identified by the pap technique. fifty per cent of the control rats exhibited widespread cerebral necrosis vs. only 15% of the immunosuppressed animals. the first cells to reach junin virus-infected cns in controls were t lymphocytes, which destroyed viral antigen-laden target neurons and astrocyte ...	1986	3005359
junin virus-induced chromosomal aberrations in the guinea pig. synergism between the attenuated strain xj-clone 3 and caffeine.	the frequency of chromosomal aberrations in bone marrow cells of guinea pigs inoculated with the pathogenic xj strain of junin virus increased significantly at 6, 9, and 11 days postinoculation (p.i.). animals inoculated with the attenuated xj-clone 3 strain only showed significant increments of achromatic lesions (gaps) at 9 days p.i. guinea pigs inoculated with the xj-clone 3 strain and then treated with two doses of caffeine 24 and 12 h before killing at 9 days p.i. exhibited a significant in ...	1985	3000979
junin virus-induced chromosomal aberrations in the guinea pig. synergism between the attenuated strain xj-clone 3 and caffeine.	the frequency of chromosomal aberrations in bone marrow cells of guinea pigs inoculated with the pathogenic xj strain of junin virus increased significantly at 6, 9, and 11 days postinoculation (p.i.). animals inoculated with the attenuated xj-clone 3 strain only showed significant increments of achromatic lesions (gaps) at 9 days p.i. guinea pigs inoculated with the xj-clone 3 strain and then treated with two doses of caffeine 24 and 12 h before killing at 9 days p.i. exhibited a significant in ...	1985	3000979
influence of cellular functions on the evolution of persistent infections with junin virus.	vero cell cultures persistently infected with junin virus and subjected to different cultural conditions were established. the production of infectious plaque-forming virus, ts mutants and interfering viral particles was determined at different times during 110 days after infection. carrier cultures maintained in stationary conditions continuously released pfu while proliferating persistent cultures exhibited a cyclical pattern which tends to a rapid pfu disappearance. concomitantly, in stationa ...	1985	2998303
astrocyte differentiation induced by junín virus in rat brain cell cultures.	morphological and immunocytochemical differentiation was observed in astroglial cell cultures of the rat infected with junín virus. from days 3 to 6 postinoculation (p.i.), gfap immunostaining was observed in both the perikaryon and processes of maturated astrocytes, whereas it was limited to the perikaryon in less differentiated cells. the rather slow spontaneous differentiation usually occurring in astroglial cell cultures was seen to be accelerated by viral infection, mimicking the astrocytic ...	1985	2990148
congenital guinea pig infection with attenuated junin virus strains.	guinea pigs born from mothers infected before or during pregnancy with 10(3) pfu of the attenuated xjc13 or xj0 strains of junin virus (jv) by the intramuscular route showed 31.5% mortality that was not attributable to the mothers' clinical condition or to lack of care. there was a slight drop in mortality rate when the mothers were infected at the beginning or end of their gestation period. jv isolation from the 9 offspring killed from 1 to 125 days of age proved that virus transmitted transpla ...	1985	2989214
congenital guinea pig infection with attenuated junin virus strains.	guinea pigs born from mothers infected before or during pregnancy with 10(3) pfu of the attenuated xjc13 or xj0 strains of junin virus (jv) by the intramuscular route showed 31.5% mortality that was not attributable to the mothers' clinical condition or to lack of care. there was a slight drop in mortality rate when the mothers were infected at the beginning or end of their gestation period. jv isolation from the 9 offspring killed from 1 to 125 days of age proved that virus transmitted transpla ...	1985	2989214
mrc-5 cells, a model for junín virus persistent infection.	persistent infection of mrc-5 cells was established following inoculation with attenuated junín virus (jv). in the acute phase of the infection both the pathogenic xj and the attenuated xj0 and xjc13 strains showed severe c.p.e. and free viral titres reached 10(5) p.f.u./ml. recovery and establishment of persistently infected mrc-5 sublines (mrc-5pi) proved a very common event and seemed to be independent of viral strain, m.o.i. employed or virus passage history. these mrc-5pi sublines released ...	1985	2987401
pathogenesis of attenuated junin virus in the guinea pig model.	the purpose of this work was to elucidate the pathogenesis of attenuated junin virus (jv) strains in the guinea pig model. three groups of guinea pigs were infected by the im route with 10(3) pfu of the xjc13 and xjo-attenuated strains or with the xj pathogenic strain of jv, respectively. viremia was studied at 3, 5, 7, 9, 12, and 14 days postinfection (pi) (a) in serum samples of all animals and in washed cells from xjc13-infected guinea pigs by conventional techniques and (b) in whole blood sa ...	1985	2983013
pathogenesis of attenuated junin virus in the guinea pig model.	the purpose of this work was to elucidate the pathogenesis of attenuated junin virus (jv) strains in the guinea pig model. three groups of guinea pigs were infected by the im route with 10(3) pfu of the xjc13 and xjo-attenuated strains or with the xj pathogenic strain of jv, respectively. viremia was studied at 3, 5, 7, 9, 12, and 14 days postinfection (pi) (a) in serum samples of all animals and in washed cells from xjc13-infected guinea pigs by conventional techniques and (b) in whole blood sa ...	1985	2983013
neurotropism of a high-passage xj strain of junín virus.	guinea pig infection with a highly passaged xj prototype strain of junín virus by the intramuscular route (im) was carried out in order to study viral tropism modification in this host. the neurotropism of this strain was demonstrated by viral isolation, meningitis, and by the presence of junín antigens as shown by immunofluorescence. these events, not previously observed with the same lower-passaged strain, revealed the appearance of neurotropism after multiple passages in guinea pigs.	1985	2983010
neurotropism of a high-passage xj strain of junín virus.	guinea pig infection with a highly passaged xj prototype strain of junín virus by the intramuscular route (im) was carried out in order to study viral tropism modification in this host. the neurotropism of this strain was demonstrated by viral isolation, meningitis, and by the presence of junín antigens as shown by immunofluorescence. these events, not previously observed with the same lower-passaged strain, revealed the appearance of neurotropism after multiple passages in guinea pigs.	1985	2983010
infection of pregnant guinea pigs with attenuated junin virus strains.	the effect of the attenuated xjc13 and xj0 strains of junin virus (jv) was studied in guinea pigs infected before and during pregnancy. the 58% mortality rate in animals infected during gestation and the 16.7% mortality rate in chronically infected animals were attributed to a viral effect. an abortion rate of 33% occurred in animals infected before the 7th week of gestation. regardless of the time of infection, jv was isolated from central nervous system tissue, placentas, and fetuses of animal ...	1985	2982762
infection of pregnant guinea pigs with attenuated junin virus strains.	the effect of the attenuated xjc13 and xj0 strains of junin virus (jv) was studied in guinea pigs infected before and during pregnancy. the 58% mortality rate in animals infected during gestation and the 16.7% mortality rate in chronically infected animals were attributed to a viral effect. an abortion rate of 33% occurred in animals infected before the 7th week of gestation. regardless of the time of infection, jv was isolated from central nervous system tissue, placentas, and fetuses of animal ...	1985	2982762
interactions of junin and tacaribe viruses during mixed infections.	the interaction between junin virus (jv) and tacaribe virus (tacv) during mixed infections of rk13 cells was examined. the effects of a prior infection with jv upon tacv replication depended on the time between the two inoculations. simultaneous infection of rk13 cells with tacv and jv did not alter the plaquing efficiency of tacv; but if there was a 1- to 24-hour delay between jv preinfection and tacv superinfection, a variable increase of tacv replication was observed. the enhancement of tacv ...	1985	2982755
effect of staggered cyclophosphamide-immunosuppression on resistance to experimental junin virus infection.	otherwise resistant adult mice were rendered susceptible to intracerebral junin virus (jv) infection only when a staggered cyclophosphamide (cy) schedule was used. forty-five-day old balb/c mice, intracerebrally jv-infected and immunosuppressed with four 50 mg/kg body weight cy doses at days -1, +1, +4, +6 (day 0: viral infection) developed a lethal disease (86.6 per cent mortality) with high cns viral titers and brain lesions. neutralizing antibodies were absent throughout, while immunofluoresc ...	1985	2982356
attenuated junin virus infection in callithrix jacchus.	twenty marmosets, male callithrix jacchus, were used during this study. fifteen of the marmosets were inoculated with 5,000 tcid50 of the attenuated xjc13 strain of junin virus by intramuscular route and five were left as uninoculated controls. animals were observed for a 420-day period. in order to carry out virologic, hematologic, serologic, and histologic studies the animals were bled and/or killed at different days post infection(pi). results obtained showed that the attenuated strain produc ...	1985	2981980
attenuated junin virus infection in callithrix jacchus.	twenty marmosets, male callithrix jacchus, were used during this study. fifteen of the marmosets were inoculated with 5,000 tcid50 of the attenuated xjc13 strain of junin virus by intramuscular route and five were left as uninoculated controls. animals were observed for a 420-day period. in order to carry out virologic, hematologic, serologic, and histologic studies the animals were bled and/or killed at different days post infection(pi). results obtained showed that the attenuated strain produc ...	1985	2981980
effect of immunosuppression on experimental argentine hemorrhagic fever in guinea pigs.	immunosuppression with cyclosporin a or cyclophosphamide had no apparent effect on the disease course of guinea pigs infected with a virulent strain of junin virus. immunosuppression of guinea pigs infected with an attenuated strain of junin virus led to fulminating argentine hemorrhagic fever. all immunosuppressed infected animals died. virus distribution patterns in target organs, as determined by plaque assay and fluorescent antibody procedures, were similar to those from non-immunosuppressed ...	1985	2981364
effect of immunosuppression on experimental argentine hemorrhagic fever in guinea pigs.	immunosuppression with cyclosporin a or cyclophosphamide had no apparent effect on the disease course of guinea pigs infected with a virulent strain of junin virus. immunosuppression of guinea pigs infected with an attenuated strain of junin virus led to fulminating argentine hemorrhagic fever. all immunosuppressed infected animals died. virus distribution patterns in target organs, as determined by plaque assay and fluorescent antibody procedures, were similar to those from non-immunosuppressed ...	1985	2981364
suppressor t-cell population induced by junin virus in adult mice.	intracerebral (i.c.) junin virus (jv) infection of adult balb/c mice is characterized by the absence of morbidity and a low mortality (barely 8-10%). in contrast, the suckling mouse model exhibits almost 100% mortality following central nervous system (cns) alterations consistent with a delayed-type hypersensitivity (dth)-like immune response. besides, jv infection of adult (resistant) mice leads to immunosuppression of dth to unrelated antigens. here we present evidence demonstrating that such ...	1988	2970429
in vivo junin virus-mouse macrophages interaction.	the role of mononuclear phagocytic cells in extraneural infection of the mouse with junin virus (jv) was studied. endpoint susceptibility (4 days of life) was evaluated by intraperitoneal (i.p.) inoculation of suckling mice. by means of immunofluorescence (if) and c3 receptor assays, it was found that macrophages were permissive to viral replication in vivo and fostered the recruitment of inflammatory cells as evidenced by the absence of c3 marker. in support, in vitro infection failed to induce ...	1988	2902768
abrogation of junin virus encephalitis by critical cyclophosphamide timing and dosage.	junin virus-induced encephalitis in suckling mouse is a delayed-type hypersensitivity reaction, whose immunopathologic nature has been proven by suppressing the thymus-dependent response. cyclophosphamide (cy) given at day +6 post-infection (p.i.) has been shown to modulate infection, presumably by tdth lymphocyte inactivation. to determine critical timing and i.p. drug dose, brain histology and survival were studied in 3-day-old balb/c mice, inoculated i.c. with junin virus. optimal protection ...	1987	2888291
junín virus persistence in mice.	newborn mice surviving intracerebral infection with junín virus (jv) strain xj showed viral persistence in brain up to 140 days post-infection (p.i.). mild meningoencephalitis or encephalitis, but not the neutralizing antibody titres (ntab) correlated with virus presence.	1987	2883864
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 ...	1985	2860803
cytolysis of junin infected target cells by immune guinea pig spleen cells.	spleen cells from guinea pigs infected with an attenuated strain of junin virus (the causative agent of argentine hemorrhagic fever) specifically lysed virus-infected syngeneic target cells in vitro. this activity was detected as early as 6 days after infection, reached a maximum on days 10-13, and persisted at lower levels, at least through day 30. monoclonal antibody to guinea pig t cells had no effect on the activity. after b or t cell enrichment techniques, the cytolysis was found with the b ...	1986	2854602
cytolysis of junin infected target cells by immune guinea pig spleen cells.	spleen cells from guinea pigs infected with an attenuated strain of junin virus (the causative agent of argentine hemorrhagic fever) specifically lysed virus-infected syngeneic target cells in vitro. this activity was detected as early as 6 days after infection, reached a maximum on days 10-13, and persisted at lower levels, at least through day 30. monoclonal antibody to guinea pig t cells had no effect on the activity. after b or t cell enrichment techniques, the cytolysis was found with the b ...	1986	2854602
[heterogeneity in the virulence of viral subpopulations derived from an attenuated strain of junin virus].		1987	2854292
susceptible adult murine model for junin virus.	the adult mouse model had been considered resistant to junin virus (jv) infection. however, we found that c3h/hej murine strain proved highly susceptible up to 5 months of age to intracerebral inoculation with the prototype xj jv strain, showing neurological signs and 80-90% mortality within 13 days. neutralizing antibodies (nt ab) were absent, but low immunofluorescent ab levels (1:5) were detected as from day +7. the virus could only be rescued by coculture of brain samples with vero cells. hi ...	1988	2850346
susceptible adult murine model for junin virus.	the adult mouse model had been considered resistant to junin virus (jv) infection. however, we found that c3h/hej murine strain proved highly susceptible up to 5 months of age to intracerebral inoculation with the prototype xj jv strain, showing neurological signs and 80-90% mortality within 13 days. neutralizing antibodies (nt ab) were absent, but low immunofluorescent ab levels (1:5) were detected as from day +7. the virus could only be rescued by coculture of brain samples with vero cells. hi ...	1988	2850346
lectin affinity of junin virus glycoproteins.	we studied the binding of junin virus (arenaviridae) glycoproteins, g1 and g2, to two insolubilized lectins. the results showed that mannose, n-acetyl-glucosamine and galactose residues were exposed on g2, while only the latter predominated on g1. heterogeneity of carbohydrate chains was found in g2, the only glycoprotein that was iodinated by the lactoperoxidase method.	1988	2849965
ribavirin prophylaxis and therapy for experimental argentine hemorrhagic fever.	junin virus-infected rhesus macaques received prophylactic and therapeutic ribavirin to assess the potential of this drug for treating humans with argentine hemorrhagic fever. when ribavirin was administered intramuscularly at the time of experimental infection with the lethal p3790 strain of junin virus, all animals were protected from clinical disease. a delay in the initiation of therapy until after the onset of illness resulted in improvement and resolution of systemic signs of disease; howe ...	1988	2848441