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Biomedical subjects

A Koestner

Publications and source records attributed to A Koestner.

At least 91 records · Page 5Linked to original sources
PubMed1977

Comparison of canine distemper virus strains in gnotobiotic dogs: effects on lymphoid tissues.

The effects of infection on various aspects of lymphoid function in gnotobiotic dogs with 2 virulent strains of canine distemper virus (CDV), Snyder-Hill CDV and R252-CDV, were compared. Both infections resulted in a viremia-related lymphopenia which was nonselective in that the percentages of B and T cells remained unchanged throughout the observation period. Nonfatal Snyder-Hill-CDV infection resulted in a transient depression of in vitro lymphocyte responses to phytohemagglutinin-P, whereas R252-CDV produced prolonged in vitro suppression of phytohemagglutinin-P stimulation. The differences observed are of minor significance and do not explain the differences in central nervous system demyelinating potential between these 1 strains of CVD.

Animals↗
PubMed1977

Experimental and naturally occurring transplacental transmission of canine distemper virus.

In the present study, 2 different effects of experimentally induced infection with virulent canine distemper virus (CDV) on pregnant CDV-susceptible dogs were studied. In 1 bitch, abortion occurred 7 days after viral inoculation and there was no evidence of fetal infection. Another bitch had subclinical infection and delivered 3 CDV-infected pups. Sequential clinical, immunologic, and virologic studies of a litter of gnotobiotic pups (3rd bitch) that were congenitally infected with CDV demonstrated the heightened susceptibility to CDV in the neonatal period. The data presented add canine distemper to the list of transplacental infectious diseases in the canine species.

Abortion, Veterinary↗
PubMed1977

Intradermal mitogen response in dogs: correlation with outcome of infection by canine distemper virus.

Gnotobiotic and conventional dogs of different ages were examined for intradermal skin test responses and in virtro peripheral blood lymphocyte responses to the phytomitogens, phytohemagglutinin-P (PHA-P) and pokeweed mitogen (PWM). All adult dogs skin tested with these mitogens demonstrated a positive skin reaction consisting of erythema and induration within 24 hours. In contrast, a positive reaction was obtained only with PHA-P when both mitogens were tested in conventional and gnotobiotic neonatal dogs. Lymphocytes from both adult and neonatal dogs underwent blastogenesis if cultured with PHA-P and PWM. Infection of gnotobiotic dogs with canine distemper virus (CDV) resulted in depression of PHA-P skin test response along with in vitro depression of lymphocyte blastogenesis. Persistent loss of skin test response correlated with eventual death due to CDV-associated encephalitis, whereas dogs which responded to PHA-P 14 to 21 days after viral inoculation survived CDV infection. The results of this study indicated that intradermal mitogen tests can be used as a rapid method for in vivo assessment of cell-mediated immunity in this species.

Animals↗
PubMed1976

Age-related susceptibility to infection with canine distemper virus in gnotobiotic dogs.

The influence of age on the susceptibility of gnotobiotic dogs to infection with virulent canine distemper virus (R252-CDV) was studied. Of the dogs infected at less than one week of age, 85% died of acute encephalitis two to five weeks after infection. In contrast, only 28.5% of infected weanling and 33.3% of infected adult dogs died after receiving inoculations of R252-CDV. Furthermore, about one-half of the fatally infected weanling dogs developed chronic encephalitis characterized by infiltration of lymphocytes and plasma cells in areas where demyelination of the central nervous system had occurred. Age-related susceptibility correlated with in vitro responses of peripheral blood lymphocytes to phytomitogens. The results of this study suggest that physiological immaturity of the immune system of neonatal dogs may account for their increased susceptibility to infection with CDV.

Acute Disease↗
PubMed1975

Primary lymphoreticuloses of the nervous system in animals.

Lymphoreticular proliferative disorders occur in most species of animals including submammalian vertebrates but only occasionally affect the nervous system. Primary lymphoreticular disorders of the nervous system have been recognized in chickens as a herpesvirus-induced avian neurolymphomatosis and in mammals, patricularly in the dog, as reticulum cell sarcomas originating from perivascular mesenchymal precursor cells. Criteria have been discussed to distinguish neoplastic from inflammatory lymphoreticuloses but borderline cases exist where a clear distinction is not always possible.

Animals↗
PubMed1975

Serologic response to canine distemper viral antigens in gnotobiotic dogs infected with canine distemper virus.

The humoral immune response to canine distemper viral antigens in gnotobiotic dogs experimentally infected with canine distemper virus was studied by the complement fixation and serum neutralization tests. Antibody titers measured by both serologic methods varied inversely with the severity of disease produced. Recovered dogs demonstrated the highest titers of antibody, whereas fatally infected dogs had little or no antibody activity in their sera. A third group of dogs, characterized by chronic persistent infection, had intermediate levels of anitbody to canine distemper virus. Preliminary characterization of the viral antigens involved in the complement fixation test indicated that at least two antigenic components were involved. One antigen was soluble in ether and was heat-labile, whereas the other was relatively heat-stable and was unaffected by treatment with ether. No evidence for serologic cross-reaction between viral and central nervous system components was found. A vigorous antibody response to envelope antigen determinants in addition to core determinants distinguished immune dogs from persistently infected dogs. The results of this study suggest that the inability to produce antibodies to envelope antigens may be a crucial factor in the establishment of a persistent infection with canine distemper virus in these dogs.

Animals↗
PubMed1975

Differential oncogenic effects of methylnitrosourea.

We investigated differences in the oncogenic effects of methylnitrosourea (MNU) which were induced by varying dose schedules and changing administration routes. The nervous system represented the target organ when MNU was given intravenously to rats. Carcinogen by other routes resulted in decreased numbers of neurogenic tumors and the appearance of neoplasms at the injection site. Increased oral doses of MNU caused shorter survival times, a decreased incidence of neuroglial tumors, and increased numbers of thymic lymphomas and mesenchymal tumors of the nervous system. The results suggest that many tissues are susceptible to the oncogenic effects of MNU, but the degree of exposure necessary for neoplastic transformation varies.

Administration, Oral↗
PubMed1975

Biological properties of a canine distemper virus isolate associated with demyelinating encephalomyelitis.

A canine distemper virus (CDV), DESIGNATED R252, originally recovered from a dog with demyelinating encephalomyelitis was shown to reproduce this disease in gnotobiotic dogs with a high incidence as compared to other CDV strains, which produced an acute fatal infection. In this investigation, R252 was propagated for the first time in Vero cells and compared to two known strains of CDV, Snyder-Hill (SH) and Onderstepoort (Ond). The results of this study revealed that intracellular R252 accumulated more slowly than either SH or Ond. There was extensive destruction of Vero monolayers infected with either R252 or SH. Each virus induced the formation of intracytoplasmic and intranuclear inclusions. Ond infection resulted in minimal cytopathic changes and intracytoplasmic inclusions. Immunofluorescence studies indicated that the spread of R252 infection within the monolayers was intermediate between the rapidly spreading SH and slowly spreading Ond. R252-infected cells developed characteristic immunofluorescent cytoplasmic inclusions. Initially, each stained homogeneously and later appeared as a non fluorescent body surrounded by a fluorescent ring. This characteristic pattern of fluorescence was observed only infrequently in thelate stage of SH infection and was absent in Ond-infected cultures. Reciprocal neutralization studies indicated that the three strains are of one serotype. These findings suggest that R252-CDV has biological properties which differ from two other strains of CDV and which may have bearing upon the in vivo capability of this virus to produce demyelinating encephalomyelitis.

Animals↗
PubMed1975

Effects of canine distemper virus infection on lymphoid function in vitro and in vivo.

In the present study, the immunodepressive effects of canine distemper virus (CDV) infection of dogs on two parameters of lymphocyte function, namely phytomitogen-induced cellular proliferation and skin allograft rejection, were investigated. Infection of susceptible gnotobiotic dogs with virulent R252-CDV resulted in a depression of peripheral blood lymphocyte mitogen response as measured by (3H)thymidine incorporation for up to 10 weeks after inoculation. This effect coincided with the appearance of viral antigen by immunofluorescence in leukocytes but persisted after the virus was no longer detectable. Loss of mitogen reactivity was seen in all infected dogs. However, when these same CDV-infected dogs were challenged with foreign skin allografts, no significant retention of grafts over controls was observed despite the depressed lymphocyte activity. Considering the in vitro and in vivo data it was concluded that, although immunodepressive effects of CDV were demonstrated in vitro, paralled in vivo experiments indicated that less than complete suppression of immune functions occurs during the course of CDV infection.

Animals↗
PubMed1975

Tumor-specific transplantation immunity to intracerebral challenge with cells from a methylnitrosourea- induced brain tumor.

Tumor-specific transplantation immunity was demonstrated in syngenic rats immunized and challenged with tumor cells (T9) from an N-methyl N-nitrosourea-induced brain tumor. All unimmunized rats and rats pretreated with normal glial cells in complete Freund's adjuvant or with adjuvant alone died of intracerebral (i.c.) neoplasia at approximately 3 weeks post-challenge. Rats which were immunized with T9 cells with or without adjuvant failed to develop i.c. tumors by 6 weeks even though the challenge dose was 2 logs greater than a dose which consistently resulted in neoplasia in unimmunized rats.

Animals↗
PubMed1975

Comparison of canine distemper viral strains: an electron microscopic study.

A canine distemper (CD) viral strain, designated R252, originally obtained from a dog with demyelinating encephalomyelitis has been shown to reproduce this disease in gnotobiotic dogs in a high incidence in contradistinction to other CD viral strains which produce an acute fatal disease. Because comparision of R252 strain with the Snyder Hill (SH) and Onderstepoort (Ond) strains revealed differences in in vitro behavior, the 3 viruses were ultrastructurally investigated. The results revealed differences among the 3 viruses: Cytoplasmic nucleocapsid aggregates were characteristic of R252, diffuse aggregates of nucleocapsids were characteristic of SH, and although budding viral particles were recognized in Ond-infected cells, few nucleocapsids were seen in the cytoplasm. Cytoplasmic fibrillar structures were characteristic of R252- and Ond-infected cells. The budding viral particles observed with R252 and SH were similar, whereas Ond budding particles seemed to contain fewer nucleocapsids. Intranuclear inclusions recognized in R252- and SH-infected cultures appeared as areas of clearing of nucleoplasm along with disruption of the nucleolus. The presence of nucleocapsid-like structures was variable. Ultrastructurally, the cytoplasmic inclusions in cells infected with all 3 viruses progressed from focal aggregates of nucleocapsids to electron-dense bodies.

Animals↗