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Biomedical subjects

R G Olsen

Publications and source records attributed to R G Olsen.

At least 91 records · Page 5Linked to original sources
PubMed1983

Immunoglobulin class response to canine distemper virus in gnotobiotic dogs.

Serial serum samples from 27 gnotobiotic dogs infected with R252-canine distemper virus (CDV) were tested for anti-viral IgG, IgM and IgA immunoglobulins using an enzyme-linked immunosorbent assay (ELISA). The results were compared retrospectively to clinicopathological course of disease and to previously reported patterns of complement-fixing and virus neutralizing antibody titers determined in these same sera. Virus-specific IgA was never detected in the sera. High levels of IgG correlated with recovery from disease, whereas the antiviral IgM levels were equivalent in both persistently infected animals and those animals which recovered from disease. The inability to sustain a significant antiviral antibody response in either IgM or IgG classes was characteristic of dogs with fatal encephalitis. The data suggests that IgG is the most important Ig class for recovery from disease.

Acute Disease↗
PubMed1983

Feline complement dependent binding in the Raji cell assay is insufficient for the quantitation of immune complexes.

A comparison was made of the binding of radiolabeled heat aggregated cat immunoglobulin G (125I-ACG) to Raji cells using normal or heat-inactivated cat or human serum. The binding with normal or heated cat serum, as well as heated human serum were essentially identical. The binding using normal human serum was 2.5- to 3-fold greater than observed with heated human serum. These results suggest that feline complement associated with 125I-ACG does not bind to Raji cells via complement receptors, but only by receptors for the Fc portion of IgG. Human serum and 125I-ACG can bind to both Fc and complement receptors on Raji cells.

Animals↗
PubMed1983

Effects of retrovirus protein on the feline one-way mixed leukocyte reaction.

The objective of this study was to evaluate the effects of feline retrovirus protein on cat lymphocyte recognition of allogeneic cells in the mixed leukocyte reaction (MLR), using u.v.-inactivated feline leukaemia virus (FeLV) and a non-disease-producing endogenous cat virus (RD-114). Twenty micrograms of u.v.-inactivated virus protein from each virus were added to mixed leukocyte cultures. FeLV induced significant suppression of the MLR (P less than 0.005) whereas no significant suppression was found using RD-114. Since feline leukaemia infection is associated with immunosuppression, the retrovirus proteins may be interfering with the response of immunocompetent cells when they are confronted with an altered host cell.

Leukemia Virus, Feline↗
PubMed1983

Lichen planus dermopathy: demonstration of a lichen planus specific epidermal antigen in affected patients.

Lichen planus is a common papulosquamous disorder of skin and mucous membranes of unknown etiology. Studies reported here demonstrate a lichen planus specific antigen (LPSA) in granular and deep prickle epithelial cells from the lichen planus lesion. Sera from seven out of eight lichen planus patients tested contained an antibody to LPSA. The LPSA was not detected in normal skin tissues from lichen planus patients, or in skin from normal donors and skin from patients with skin disorders other than lichen planus. A serologic survey of serum from people with no clinical history of lichen planus revealed approximately a 7% incidence of antibody to LPSA. These studies suggest that LPSA may be of exogenous origin.

Adolescent↗
PubMed1983

Systemic and local intestinal antibody response in dogs given both infective and inactivated canine parvovirus.

Systemic and local immune responses were evaluated in dogs given infective canine parvovirus (CPV) and 2 administrations of inactivated CPV 6 months later. Before the inactivated CPV was given, a jejunal cannulation was performed on the animals. During infective CPV administration, concentrations of class-specific copro- and sero-immunoglobulin (Ig)G, IgA, and IgM were determined by enzyme-linked immunosorbent assay. High concentrations of both copro- and sero-IgM, as well as a moderate increase in the concentrations of sero-IgG and copro-IgA, were detected within 3 days after experimental challenge. Hemagglutination inhibition titers correlated with both serum anti-CPV IgG and IgM early and serum anti-CPV IgG in the later states of infection. After 2 oral administrations of inactivated CPV, class-specific jejuno-, copro-, and sero-IgG, IgM, and IgA anti-CPV antibodies also were determined by enzyme-linked immunosorbent assay. High concentrations of jejuno-IgM and moderate levels of jejuno-IgG and IgA were found. Copro-IgM was not detected in the feces; however copro-IgG and IgA were. Also, no correlations were found to exist when sero-IgM and IgG were compared with jejuno- and coproantibody concentrations throughout the experimental period. Thus, it appears that the immune responses to CPV include both a secretory component of the intestinal mucosa and a systemic component of peripheral lymphoid tissues. Application of the modified Witzel's enterostomy to this study of local intestinal immunity proved beneficial. The technique was well tolerated by experimental animals and allowed for simple, multiple sample collections of intestinal contents for virus and antibody determinations with apparently minimal alterations in the luminal environment.

Animals↗
PubMed1982

Reactivation of latent feline leukaemia virus infection.

In most cats exposed to the contagious feline leukemia virus (FeLV), viral replication is contained in target haematopoietic tissues and elicits humoral immunity to FeLV and to the feline oncornavirus-associated cell membrane antigen (FOCMA). Recently, we and others have considered that these ostensibly self-limiting infections might be persistent nonproductive (latent) infections in certain haematopoietic cells. This hypothesis could account for the relapsing viraemias, protracted incubation periods, persistently high titres of antiviral and anti-FOCMA antibodies, appearance of FeLV p27 antigen in serum of otherwise non-viraemic animals and occurrence of FeLV-negative but FOCMA-positive leukaemias in naturally infected pet cats. Here we describe the reactivation of latent FeLV from myelomonocytic and lymphoid cells of cats immune to FeLV, cats bearing FeLV-negative tumours, and kittens congenitally exposed to FeLV. Furthermore, the reappearance of FeLV infection is suppressed by the Host's immune system but his can be altered by adrenal corticosteroid hormones in vivo and in vitro.

Adrenal Cortex Hormones↗
PubMed1982

Canine parvovirus infection potentiates canine distemper encephalitis attributable to modified live-virus vaccine.

Twelve gnotobiotic dogs from 2 litters were allotted to 3 groups. Group A dogs received a modified-live polyvalent (canine distemper, adenovirus type 2, and parainfluenza virus and Leptospira -canicola-icterohemorrhagiae bacterin) vaccine 3 days prior to oral inoculation with canine parvovirus (CPV). Group B dogs received CPV alone. Group C dogs received 1 dose of vaccine only. In none of the 9 CPV-inoculated dogs did clinical signs of CPV infection develop, although high serum antibody titers for CPV developed in all of them. However, in 2 of the 5 CPV-inoculated vaccinates, canine distemper virus encephalomyelitis subsequently developed. The results suggested that CPV exerts an immunomodulating effect on canine immune responses and may be responsible for vaccination failures in dogs.

Animals↗
PubMed1982

Electromagnetic dosimetry in a sitting rhesus model at 225 MHz.

Dosimetric measurements in a 9.5-kg tissue-equivalent rhesus model were conducted at 225 MHz using a nonperturbing temperature probe and a gradient-layer calorimeter. Temperature probe measurements showed deep penetration of electromagnetic energy, and calorimeter experiments showed an average SAR (0.285 W/kg per mW/cm2) that was nearly three times greater than that observed for the same model at 1.29 GHz.

Animals↗
PubMed1982

Far-field dosimetric measurements in a full-sized man model at 2.0 GHz.

Electromagnetic dosimetry was conducted in a tissue-equivalent full-sized model of man irradiated at 2 GHz inside a microwave-anechoic chamber. A nonperturbing temperature probe and a gradient-layer calorimeter were used to determine local and whole-body specific absorption rate (SAR), respectively. Relatively high SAR values were found in the limbs compared to the axis of the trunk of the model. The calorimeter experiments yielded an average SAR about three times higher than that estimated theoretically for a prolate spheroidal model of man. It is suggested that resonant interactions involving the limbs may be responsible for the disparity between theory and experiment.

Humans↗
PubMed1982

In vivo and in vitro effects of 1,1-dimethylhydrazine on selected immune functions.

The in vivo phase of the experiments reported here include the evaluation of immune function after short-or long-term treatment of mice with 1,1-dimethylhydrazine (UDMH). Long-term exposure (3 injections/week for 14 weeks) resulted in increased numbers of Jerne plaque-forming cells, a trend toward decreased induction of suppressor cell activity by concanavalin A (Con A), and no effects on mitogen-induced lymphocyte blast transformation (LBT), compared to saline-treated control mice. These effects were greatest at doses of 10 or 50 mg/kg, while higher doses had less of an effect. In vitro experiments were performed by adding UDMH to normal murine splenocytes in the LBT assay and con A-induced suppressor cell assay. The UDMH induced a significant enhanced response to lipopolysaccharide (LPS) at 10 and 50 micrograms/ml, and a suppressed response to both Con A and LPS at higher concentrations. The UDMH also caused a decrease in suppressor cell activity at 25 micrograms/ml. Selective abrogation of suppressor activity or alteration of the suppressor cell-helper ratio were suggested as possible mechanisms for the enhancement effect associated with UDMH.

Animals↗
PubMed1982

Comparison of systemic and local immunity in dogs with canine parvovirus gastroenteritis.

To determine whether resistance to canine parvovirus (CPV) gastroenteritis is mediated by local or systemic immunity or both, an enzyme-linked immunospecific antibody assay (ELISA) was developed that quantitated different classes of antibody to CPV. Antibody levels in serum and feces of dogs with CPV-associated gastroenteritis were compared with their clinical signs and viral hemagglutination (HA) titers. Dogs with high levels of CPV coproantibody had a favorable clinical prognosis, high serum antibody levels (hemagglutination inhibition [HI] and ELISA), and low viral HA titers in feces. Conversely, dogs with little or no detectable CPV coproantibody had severe clinical signs and associated mortality rates and high viral HA titers in feces. Many of these dogs had high HI antibody titers. Statistical analysis revealed that only coproantibody level correlated (inversely) with HA titer; serum antibody, whether measured by HI or ELISA, did not. These data suggest that local intestinal immunity is more important than humoral immunity in developing immunological resistance to CPV gastroenteritis.

Animals↗
PubMed1982

Characterization and mitogenesis of feline lymphocyte populations.

Feline lymphocyte populations from blood, spleen, lymph node, thymus and bone marrow were examined for the following markers: rosette formation with guinea pig erythrocytes (GPE-T cells); surface feline thymocyte antigen (T cells); surface immunoglobulin (B cells); cytoplasmic immunoglobulin (preB cells, plasma cells); receptors for the Fc portion of IgG (FcyR-positive T and B cells), and the third component of complement (CR-positive cells - primarily B cells). The blastogenic responses of feline lymphocytes from peripheral blood, spleen, lymph node (LN), thymus and marrow were investigated using the following mitogens: Escherichia coli lipopolysaccharide (LPS), dextran sulfate (DxS), concanavalin A (conA), phytohemagglutinin (PHA) and pokeweed mitogen (PWM). Feline T lymphocytes identified by rosette formation with GPE and surface thymocyte antigen were present in thymus, spleen, LN, blood and, rarely, in marrow. T cell subsets, but not B cell subsets, were differentiated according to mitogen activation. Cells responding to PHA were immature, nonrecirculating cells, which were most strongly activated in thymus [stimulation index (SI) = 12], lymph node (SI = 11) and spleen (SI = 6). PWM-responsive cells were relatively mature, recirculating lymphocytes of widespread distribution and blastogenesis was greater in spleen (SI = 36) and LN (SI = 29), followed by thymus (SI = 23) and blood (SI = 15). Con A was a potent mitogen for cells of spleen (SI = 113), blood (SI = 80) and LN (SI = 77), but not thymus (SI = 7), suggesting that the con-A-inducible cell was a mature, recirculating, postthymic cell. Optimal mitogenic response to the B cell mitogen, LPS, was dependent upon increased cell concentrations (3 x 10(5) versus 1 x 10(5) per microtiter well) and increased incubation time (5 days versus 3 days). Surface IgG- and IgM-bearing lymphocytes and CR-bearing cells from spleen and blood were stimulated preferentially. DxS was moderately mitogenic for CR-bearing lymphocytes in spleen (SI = 4), LN (SI = 3) and blood (SI = 3), but not marrow (SI = 1).

Animals↗
PubMed1982

Loss of the short-lived suppressive function of peripheral leukocytes in feline retrovirus-infected cats.

Normal feline peripheral blood mononuclear cells demonstrated increased phytomitogen blast transformation after a 24 hr delay in mitogen addition as compared to 0 hr mitogenesis. Increased stimulation after 24 hr which is not due to enhancing factors accumulating in the culture medium has been attributed to a short-lived suppressor cell which loses its effect after 24 hr in culture. This short-lived suppressive phenomenon was studied in normal specific-pathogen-free cats and compared to experimental animals infected with retrovirus (FeLV). Experimental cats demonstrated a subsequent loss of this function following acquisition of a persistent viremia.

Animals↗
PubMed1981

Protection against feline leukemia by vaccination with a subunit vaccine.

An effective vaccine against feline leukemia virus infection has been developed by the collection and concentration of tissue culture medium harvested from a tumor cell line. Lymphoid cells were grown to near saturation density in a normal growth medium and then transferred to a serum-free medium. The serum-free medium was collected, concentrated, and evaluated for its vaccine potential. Cats receiving the vaccine emulsified in complete Freund adjuvant developed high antiviral and antitumor titers and were protected (81%) against virus challenge. Cats receiving the vaccine without an adjuvant developed lower antibody levels and lower protection (53%) from viremia. Age-matched and litter-matched controls developed no antibody to test antigens before the challenge, and 100% became persistently viremic after the challenge. Vaccination with the soluble tumor cell antigen vaccine proved successful in preventing the induction of feline leukemia virus infection.

Adjuvants, Immunologic↗
PubMed1981

Induction of retinal degeneration in cats by methylnitrosourea and ketamine hydrochloride.

Persistent mydriasis seen in cats used in an oncology study apparently was not related to neoplasia. Ophthalmoscopically, the cats had severely atrophic retinas and clinically observable visual impairment. These findings were confirmed by electroretinographic and histologic examination. Cats with these retinal lesions had received combinations of methylnitrosourea, ketamine hydrochloride, and feline leukemia virus. Retinopathy was not seen in ketamine-anesthetized cats receiving feline leukemia virus. To test the nature of this phenomenon, four cats were given both drugs and three received methylnitrosourea alone. The four cats developed severe generalized retinal degeneration by day 5, whereas the three cats given methylnitrosourea alone had normal retinas. Histologic changes in the affected cats were extensive loss of rods and cones, and of the outer nuclear layer. The electroretinographic responses to white light were depressed or extinguished. Retinal degeneration, therefore, appeared to be dependent upon administration of both methylnitrosourea and ketamine hydrochloride.

Animals↗
PubMed1981

Infection of feline embryo adherent cells with feline leukemia virus: feline oncornavirus-associated cell membrane antigen expression and morphologic transformation.

Feline embryo adherent cells were infected with the Richard or Kawakami-Theilen strains of feline leukemia virus (FeLV) and examined for feline oncornavirus-associated cell membrane antigen (FOCMA), viral group-specific antigen (gsa) production, and in vitro evidence of transformation. As early as 10 days after infection, when more than half of the infected cells were gsa positive, FOCMA was detected on 5-10 percent of the cells. Transitory morphologic alterations (epithelioid appearance and rounding) were first noted in most cultures around 20-30 days post infection. At this time, approximately 50% of the cells in infected cultures expressed FOCMA. Morphologic characteristics of transformed fibroblastic cells (rounded shape, disordered alignment, and low adhesion to substratum), as well as enhanced agglutinability by plant lectins and ability to grow in agar, were demonstrated in one of four FeLV-infected, FOCMA-positive cultures. Findings showed that FOCMA may be expressed in FeLV-infected monolayer cells independent of transformation as assessed by in vitro criteria.

Agglutination Tests↗