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Biomedical subjects

O Vainio

Publications and source records attributed to O Vainio.

137 records · Page 8Linked to original sources
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↗
PubMed1979

Formation of germinal centres during neonatal tolerance in the chicken.

Chickens were made tolerant to BSA at the time of hatching. During the tolerance, antigenic stimulation with BSA resulted in poor germinal centre formation as compared to normal immunized control birds. The tolerance persisted for at least 6 weeks. Its breakdown had hardly started at the age of 12 weeks, both IgM and IgG antibody responses against BSA remaining negligible. Stimulation with the unrelated antigens SRBC and Brucella abortus resulted in good antibody responses, but the number of germinal centres was smaller in the tolerant birds than in normal controls.

Animals↗
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↗
PubMed1974

Complete restoration of bursa-dependent immune system after transplantation of semiallogeneic stem cells into immunodeficient chicks.

For transplantation of semiallogeneic bursal stem cells into cyclophosphamide-treated 3-day old chicks, two lines of chickens homozygous at the major histocompatibility locus and their F(1) hybrids were used in reciprocal combinations. The semiallogeneic transplantations resulted in a complete restoration of antibody formation to sheep red blood cells (SRBC) and Brucella, of microscopic morphology of bursa fabricii, and of germinal center formation in the spleen. In contrast, allogeneic bursal stem cells were not effective in restoring secondary response to SRBC and germinal center formation, while they were able to reconstitute anti-Brucella responses and bursal morphology. These findings indicate an effective cooperation of donor and host cells leading to a complete restoration of the bursa-dependent lymphoid system, when the donor and recipient share at least one haplotype determining the major histocompatibility antigen complex.

Animals↗
PubMedDate not supplied

Renewal of thymocyte progenitors and emigration of thymocytes during avian development.

The avian thymus is colonized by three waves of hemopoietic progenitors during embryogenesis. An in vivo thymus reconstitution assay based on intrathymic injection of irradiated chicks showed that cells of para-aortic foci were able to differentiate into T lymphocytes, confirming their putative role in the first wave of thymus colonization. This assay was also used to detect and to characterize T cell progenitors from the bone marrow which are involved in the second and third wave of thymus colonization. In the bone marrow, progenitors that differentiated into T cells were found in a subpopulation that expressed the molecules HEMCAM, c-kit and c128. Engraftment of thymus lobes into thymectomized young chick recipients showed that T cell progenitors are replaced in the thymus by subsequent waves of progenitors after hatching. Finally, analysis of thymocyte differentiation suggested that gamma delta and alpha beta T cells migrate from the thymus to the periphery in alternating waves.

Animals↗
PubMedDate not supplied

Structure and chromosomal localization of chicken CD5.

CD5 is a transmembrane glycoprotein on all T cells and on a subpopulation of B cells. Based on the analysis of chicken CD5-cDNA we have previously shown that the structure of the CD5 protein is conserved between species. Here we report the isolation and chromosomal mapping of the chicken CD5 gene. The gene spans 3.4 kb and is extremely compact with a high GC-nucleotide content. There are 10 exons and the introns are spliced out similarly to those in the human CD5 gene. Each of the three extracellular scavenger receptor cysteine-rich (SRCR) domains is encoded as an exon of its own, as is the proline-rich hinge region that separates the first two membrane-distal SRCR domains. The fluorescence in situ hybridization (FISH) technique was used to map the gene to chromosome five. This is the first report describing the organization of the CD5 gene from a nonmammalian species.

Animals↗
PubMedDate not supplied

The influence of detomidine and epinephrine on heart rate, arterial blood pressure, and cardiac arrhythmia in horses.

Detomidine (10 micrograms/kg and 20 micrograms/kg) was administered to seven horses with and without epinephrine infusion (0.1 microgram/kg/min) from 5 minutes before to 5 minutes after detomidine injection. One or more single supraventricular premature heartbeats were observed in three horses after detomidine administration. Epinephrine infusion did not modify the incidence of cardiac arrhythmias in detomidine-treated horses at the doses tested. Relatively high momentary peak systolic pressures were registered in some horses after detomidine administration during epinephrine infusion. The highest systolic arterial blood pressure was 290 mm Hg, but this value was not higher than that reported in horses during maximum physical exercise. Epinephrine infusion did not alter blood gases, arterial pH, or base excess.

Analgesics↗
PubMedDate not supplied

Detomidine in pregnant cows.

Evidence that the course of gestation in dairy cattle is not influenced by the administration of detomidine, a novel sedative and analgesic agent.

Animals↗