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C Johnsson

Publications and source records attributed to C Johnsson.

52 records · Page 3Linked to original sources
PubMed1994

MC 1288--a vitamin D analogue with immunosuppressive effects on heart and small bowel grafts.

The vitamin D analogue MC 1288 (20-epi-1 alpha,25-dihydroxycholecalciferol) was tested here for its possible immunosuppressive properties in vivo using different rat transplantation models. MC 1288, in a dose of 0.1 microgram/kg daily, administered intraperitoneally for 10 days, was found to be effective in prolonging cardiac allograft survival. Untreated recipients rejected their grafts around day 8 while MC 1288 treatment delayed rejection until day 22 (P < 0.001). Addition of the immunostimulatory drug LS-2616 (Linomide) reduced the immunosuppressive effect of MC 1288 and rejection occurred around day 11. The immunosuppressive effect of MC 1288 on rejection following small bowel transplantation was determined by measuring the amounts of hyaluronan (HA) secreted into the intestinal lumen. On day 6 post-transplantation the amounts of intraluminal HA in untreated animals was 29.2 +/- 5.3 ng/min and cm, while in MC 1288-treated animals it was just 5.0 +/- 1.6 ng/min and cm (P < 0.01). We conclude that MC 1288 has immunosuppressive effects that may make it suitable for the prevention of graft rejection.

Adjuvants, Immunologic↗
PubMed1994

The immunomodulator LS-2616 (linomide) more effectively than sensitization of the donor enhances graft-versus-host reaction after small bowel transplantation.

The effects of the immunomodulating substance LS-2616 (linomide) on graft-versus-host reaction (GVHR) were investigated in a semi-syngeneic small bowel transplantation model. The entire bowel of Lewis donors were transplanted heterotopically into (Lewis x BN) F1 hybrids. Both untreated animals and animals treated with LS-2616, in a daily dose of 160 mg/kg, developed a lethal GVHR. The median survival time in untreated animals was 14.5 days while in LS-2616 treated animals it was just eight days (p < 0.01). LS-2616 in combination with cyclosporin A (CyA), 15 mg/kg given orally on days 0-20, did not seem to alter the survival times compared with CyA treatment alone; 56% of the animals treated with CyA survived for more than 100 days and after combined treatment with CyA/LS-2616 there were 50% permanent survivors. Also the effect of earlier sensitization of the donor on the course of GVHR was investigated. Hearts from BN rats were transplanted heterotopically to the neck vessels of Lewis rats. The hearts were rejected on about day six; five days later the bowels were harvested and transplanted into (Lewis x BN) F1 hybrids. The median survival time in this group was 12.5 days. Taken together our results, in combination with earlier findings, suggest that, at the level of effector mechanisms, GVHR is not an exact mirror image of rejection. Also, LS-2616 appears to be a useful tool for further studies of the mechanisms of action of GVHR.

Adjuvants, Immunologic↗
PubMed1993

Recovery of hyaluronan during perfusion of small bowel transplantation reflects rejection.

Rejection seen after small bowel transplantation (SBT) in the rat is associated with an accumulation of hyaluronan (HA) in the lamina propria of the graft. In this study the intestinal intraluminal content of this connective tissue component was measured in order to determine if HA could be used as an index of rejection following SBT. Syngeneically and semiallogeneically transplanted rats were investigated by perfusion of a 4-cm segment of the intestinal graft on days 2, 4, and 6 posttransplantation. The amounts of HA recovered during perfusion were analyzed using a radiometric assay. In rejecting grafts the recovered HA amounts increased 15 times from day 2 to day 6, although after syngeneic transplantation there was only a minor increase from day 2 to day 4 and no further increase on day 6. Thus, the recovery of HA during perfusion of transplanted small bowel grafts has the potential value to reflect rejection.

Animals↗
PubMed1991

Intravenous or cold ex vivo administration of monoclonal antibodies for conditioning of rat small-bowel allografts.

The following study describes cold ex vivo or intravenous infusion of monoclonal antibodies (MCAB) for lymphocyte target cells of rat small-bowel grafts. The MCAB Ox8, directed against CD8+ T lymphocytes, is used here as a model antibody. We demonstrate that Ox8 antibodies administered during cold ex vivo perfusion are able to reach the target cells in the small-bowel mucosa and the mesenteric lymph nodes of rat small-bowel grafts. Thus, cold perfusion of the vascular system for 20-60 min resulted in good labelling of the CD8+ T cells as analysed on cryostat tissue sections using immunoperoxidase staining. Rats treated with Ox8 intravenously 60 min before taking of specimens showed similar labelling. Additional staining of the tissue sections with Ox8 antibody resulted in no further labelling, thus indicating that nearly all CD8+ T cells were labelled both after ex vivo perfusion and after intravenous treatment of the donor. It is concluded that MCAB can, as an alternative to the intravenous route, be administered ex vivo after organ harvesting.

Animals↗
PubMed1987

Two highly polymorphic minisatellites from the pseudoautosomal region of the human sex chromosomes.

Two pseudoautosomal loci DXYS15 and DXYS17 from the pairing region of the human sex chromosomes display a high variability with at least eight alleles each. The structural elements responsible for the polymorphisms have been isolated and sequenced. In both cases the variations result from DNA rearrangements occurring in tandemly repeated sequences (minisatellites) of 21-29 nucleotides for DXYS15 and 28-33 nucleotides for DXYS17. At reduced stringency, the DXYS15 minisatellite detects other hypervariable sequences located in other parts of the genome and hence represents a new family of minisatellites. In contrast to most other known hypervariable families, the DXYS15 hypervariable sequence displays a very high AT content.

Alleles↗
PubMed1986

A DNA probe detecting multiple haplotypes of the human Y chromosome.

We have characterized a DNA probe (49f) that detects about 15 Y-specific TaqI bands corresponding to a low-copy number sequence. Five of these bands, each representing a single DNA fragment, can either be present, absent, or variable in length. Familial segregation studies have shown that the variations of these fragments are inherited in a Mendelian fashion and strictly Y-linked. A survey of 44 male individuals indicated that the five variable TaqI fragments detected by probe 49f can be considered as five independent allelic series. Each series represents the different and mutually exclusive allelic forms observed for a single DNA fragment. A total of 16 haplotypes, each defined by a different combination of the various forms of each of these five restriction fragment length polymorphisms, were observed among the 44 scored individuals. These TaqI restriction polymorphisms are not observed with other restriction digests and have therefore been attributed to point mutations. The five polymorphic fragments map to Yq11, a region that does not recombine with the X chromosome and are therefore not redistributed. This implies that an apparently independent reassortment of one of these series with respect to the others can be explained only on the basis of mutations that occurred several times (or reverted) during evolution of the Y chromosome. However, an examination of the different combinations of two or more allelic series suggests that some alleles are not randomly distributed and raises the possibility of establishing a genealogy of the human Y chromosome.

Alleles↗
PubMedDate not supplied

A gradient of sex linkage in the pseudoautosomal region of the human sex chromosomes.

Three independent pseudoautosomal loci are linked to sex determination at frequencies which define a gradient of linkage. The segregation patterns of these loci indicate that X/Y recombination results from a single obligatory meiotic crossing-over in the pseudoautosomal region. Recombination in male germ cells in the terminal regions of the short arms of the X and Y chromosomes in 10-fold greater than between the same regions of the X chromosomes in female germ cells.

Animals↗