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Biomedical subjects

A Toivanen

Publications and source records attributed to A Toivanen.

At least 55 records · Page 3Linked to original sources
PubMed1987

Characterization of circulating Yersinia-specific immune complexes in patients with yersiniosis.

The size of immune complexes (ICs) containing Yersinia enterocolitica antigens was studied by size exclusion high-pressure liquid chromatography and sucrose density gradient ultracentrifugation in sera of patients with recent yersiniosis. The ICs detected were relatively small, i.e., of equal size to or slightly larger than the corresponding anti-Yersinia antibodies. The size of the ICs was equal in the patients with Yersinia-triggered reactive arthritis and in those recovering without complications. No changes were observed during a follow-up. The equal size of ICs in the patients with and without arthritis also suggests that antigens and antibodies involved are similar in both patient groups. Taken together with our earlier findings indicating occurrence of high concentrations of Yersinia IgM ICs in the arthritic patients, the present results suggest that Yersinia--IgM ICs have a role in the pathogenesis of Yersinia-triggered reactive arthritis.

Antibodies, Bacterial↗
PubMed1987

Immunoblot analysis of human IgM, IgG and IgA responses to plasmid-encoded antigens of Yersinia enterocolitica serovar O3.

Human IgM, IgG and IgA responses after infection with Yersinia enterocolitica serovar O3 were studied by immunoblotting sera against whole-cell homogenates of a plasmid-containing strain of Y. enterocolitica O3 and a plasmid-free strain derived from it; each strain was grown in conditions expressive for the plasmid. The antibodies observed were directed against several plasmid-encoded polypeptides. The response against different bacterial components decreased uniformly with time and the persisting antibody production was directed against several epitopes. Strong reactions to the prominent plasmid-specified antigens of mol. wts (10(3] 26, 34, 45 and 52.5 were found more often with IgG-class antibodies than with IgM or IgA; the latter immunoglobulins recognised, respectively, antigens of mol. wt (10(3] 26 and 45 (IgM) and 26, 34 and 52.5 (IgA). Immunoblotting of sera from patients with yersinia-triggered reactive arthritis did not reveal any antigens that were involved additionally or specifically. However, IgA-mediated recognition of certain antigens of mol. wts (10(3] 26, 34 and 52.5 tended to persist longer in the arthritic patients.

Adolescent↗
PubMed1987

Graft-versus-leukaemia activity associated with cytomegalovirus seropositive bone marrow donors but separated from graft-versus-host disease in allograft recipients with AML.

To elucidate whether a relationship existed between bone marrow donor cytomegalovirus (CMV) immune status and the probability of staying in remission after transplantation, a retrospective multicentre analysis was performed in 69 patients who received allogeneic bone marrow transplantation during relapse or second remission of AML, or second remission of ALL. None of 12 AML patients with CMV seropositive donors had posttransplant relapse, in contrast to 7 of 10 AML patients with seronegative donors. Kaplan-Meier estimates of the 2-yr probability of staying in remission for the two groups were 100% and 0%, respectively (p less than 0.0005). This effect was independent of disease stage, donor and recipient age, recipient pretransplant CMV immune status and the occurrence of posttransplant CMV infection in recipients, and was not mediated through an increased occurrence of overt graft-versus-host disease (GvHD) in recipients with CMV seropositive donors. The increased probability of staying in remission was associated with an increased probability of 3-yr disease-free survival (p less than 0.01). No similar effect was observed in patients with ALL. This study may suggest an allograft-versus-leukaemia effect in AML, associated with CMV seropositive donors, which seems separate from GvHD and independent of the occurrence of posttransplant CMV infection.

Adolescent↗
PubMed1987

Immunoblotting analysis of human IgM, IgG and IgA response to chromosomally coded antigens of Yersinia enterocolitica 0:3.

Human antibody response after Yersinia enterocolitica infection was studied by immunoblotting sequentially collected sera against a whole-cell homogenate of Y. enterocolitica serotype 0:3, grown under conditions restrictive for the plasmid. The antibodies observed were directed against a multitude of chromosomally coded antigens, and a considerable individual heterogeneity was found in the reactions of individual sera. The early (0-2 months) and late (greater than or equal to 11 months) responses were directed against the same antigenic determinants. Antibodies against different bacterial epitopes decreased evenly with time, indicating that several, if not all, antigenic epitopes of the bacteria are responsible for the prolonged antibody production. IgM responses by most patients declined within a few months but were surprisingly strong in some even one year after onset of the infection. IgG antibodies showed a strong reaction against a region corresponding to lipid A and core of the bacterial LPS, whereas IgM and IgA recognized this region less often. No other significant differences between IgM, IgG and IgA responses were observed. Immunoblotting of sera from patients with post-infection complications (arthritis, iritis, erythema nodosum) did not reveal any additional or specifically involved antigens. Altogether, these findings suggest that Yersiniae causing the original infection may hide in some of the patients for prolonged periods.

Antibodies, Bacterial↗
PubMed1987

Failure to prevent cytomegalovirus infection by cytomegalovirus hyperimmune plasma: a randomized trial by the Nordic Bone Marrow Transplantation Group.

Bone marrow transplantation recipients who were cytomegalovirus (CMV) seropositive and/or had a CMV seropositive donor were randomized for treatment with CMV hyperimmune plasma (n = 27) or no treatment at all (n = 27). The CMV hyperimmune plasma had neutralization titers greater than 250 and enzyme-linked immunosorbent assay titers greater than 18,000. Plasma (200 mg/kg body weight) was given on four occasions (during 2 days) from day 3 to day 76 after transplantation. Patient characteristics were similar in the two groups. After transplantation, the median CMV titers increased with greater than 100% in the group receiving the CMV plasma and decreased to less than 50% in the controls (p less than 0.01). Asymptomatic CMV infections occurred in 26% of the patients in the plasma group and 33% of the controls. The frequency of patients with symptomatic CMV infections was also the same in the two groups (51% vs 33%). Three patients each in the two groups developed CMV-associated interstitial pneumonitis. Patient survival and causes of death were similar in the two groups. To conclude, no beneficial effect of CMV hyperimmune plasma was seen in patients at high risk of developing CMV infections.

Antibodies, Viral↗
PubMed1986

Restriction map of virulence plasmid in Yersinia enterocolitica O:3.

Restriction map of the 72-kb virulence plasmid isolated from Yersinia enterocolitica O:3 was generated using EcoRI, BamHI, HindIII, and XbaI restriction enzymes. The mapping was done after cloning all of the 13 BamHI fragments of the plasmid in Escherichia coli. In addition, the restriction enzyme analysis revealed two types of virulence plasmids (types I and II) in Y. enterocolitica O:3. No functional differences between the strains bearing type I or type II plasmid were observed.

Arthritis, Infectious↗
PubMed1979

Germinal center formation in BSA-tolerant chickens.

In chickens rendered neonatally tolerant to BSA the germinal center formation was significantly decreased after stimulation with BSA at the age of 3 weeks. At the breakdown of tolerance after the age of 6 weeks the IgG antibody formations recovered before the IgM production. Stimulation of tolerant birds with unrelated antigens resulted in slightly decreased antibody response but the germinal center formation was on the same level as in normal controls.

Aging↗
PubMed1979

Prolonged BCG treatment of melanoma: does it suppress the immune capacity?

The immunological status of seven patients with disseminated melanoma during BCG scarification was followed. As parameters, the total peripheral blood leukocyte and lymphocyte counts, serum immunoglobulin levels, natural ABO blood group antibodies, lymphocyte responses in vitro to PHA and PPD, and skin reactivity against PPD and candidin were followed during a period of 2--36 months. The EAC-rosette-forming cells increased and the E-rosette-forming cells decreased during prolonged BCG therapy. The skin reactions and lymphocyte responses showed in most patients conversion from negative to positive or augmentation at the start of the therapy. Later on, however, the values in most patients dropped before disseminated disease became clinically apparent. In the only surviving patient the values first increased, remained high, and after 100 weeks treatment decreased. After 140 weeks' treatment immunological parameters are similar to pre-treatment levels. The possibility that prolonged intensive BCG treatment might eventually suppress the immune system, and thus result in an enhanced risk of dissemination of the disease, is discussed.

BCG Vaccine↗
PubMed1979

Maturation of bursal stem cells within allogeneic or syngeneic bursal microenvironment: acquisition of postbursal maturity.

Differentiation of bursal stem cells in an allogeneic or syngeneic bursal microenvironment was compared. Bursal stem cells were transplanted into CY-treated 4-day-old recipients and permitted to differentiate in these hosts for 6 weeks. Their maturity degree was thereafter assessed by transplanting them into secondary recipients by using morphologic and functional criteria. As the secondary recipients 4-day-old CY-treated or CY-treated and surgically bursectomized chicks were used. The results obtained demonstrate that bursal stem cells develop to mature postbursal cells also within an allogeneic bursa. They also indicate that although the interaction of different lymphoid cells requires histocompatibility, the interaction between stromal cells in the bursa and lymphoid progenitors is not genetically restricted.

Animals↗
PubMed1978

Is group-specific meningococcal vaccination resulting in epidemics caused by groups of virulent meningococci?

In 1976 routine vaccination against Neisseria meningitidis serogroups A and C was started in the Finnish Armed Forces. A case of fulminant, complicated pneumonia caused by group-Y meningococcus in a vaccinated recruit, prompted a study of the distribution of the meningococcal groups isolated from the recruits in the same unit. 14 (46%) of the 31 isolates from 84 recruits were group Y. Group-Y meningococcus was rarely isolated from unvaccinated controls. These results suggest that widespread vaccination against serogroups A and C may have led to an increase in the frequency of meningococcus group Y.

Bacterial Vaccines↗
PubMed1978

The influence of 5-fluorouracil on cellular and humoral immunity in cancer patients.

The effects of 5-fluorouracil (5-FU) on the immune functions of twelve patients with disseminated cancer were studied, using as parameters the peripheral blood lymphocyte count, serum immunoglobulin levels, titers of natural blood group antibodies, percentages of E and EAC rosette forming cells, and lymphocyte proliferative responses to PHA and PPD. No effects on the humoral immune functions or on the percentages of E and EAC rosette forming cells were observed. 5-FU caused a decrease in the proliferative responses of lymphocytes to PHA and PPD. The patients could be divided into two groups: those surviving for six months or more, and those succumbing earlier. The latter ones had already initially poor proliferative responses, particularly to PPD, and the response strongly decreased during the 5-FU treatment. In the patients with a longer survival time, the effects of 5-FU on the PPD and PHA responses were not as striking.

Antibody Formation↗
PubMed1978

Early ontogeny of germinal center formation in the chicken.

Germinal center formation was studied in the spleen of young chickens immunized in ovo and at the time of hatching. When immunization was performed on day 18 in ovo and on the day of hatching, the first germinal centers were observed at 4 days. This is markedly earlier than in unimmunized chickens, where the first germinal centers appear at the age of 10 days or later. Germinal center formation preceded significant antibody production. The possible role of germinal centers in the generation of immunological memory is discussed in the light of these and earlier observations.

Aging↗