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Biomedical subjects

T Gedde-Dahl

Publications and source records attributed to T Gedde-Dahl.

At least 127 records · Page 7Linked to original sources

Ultrastructural studies in epidermolysis bullosa hereditaria. IV. Recessive dystrophic types with junctional blistering. (Infantile or Herlitz-Pearson type and adult type).

Recessive dystrophic epidermolysis bullosa with junctional blisters includes both the classical epidermolysis bullosa hereditaria letalis Herlitz (Herlitz-Pearson type) and a recently separated more benign adult type. Ultrastructural examination was performed of 13 skin specimens from 3 cases of the Herlitz-Pearson-type and one case of the adult type. Principal ultrastructural changes in involved, intact and experimentally frictioned skin regions, common to all patients, are as follows: In nonseparated areas hypoplasia of the hemi-desmosomes and mild decrease of the tonofibrils are found. Hypoplasia of hemi-desmosomes consists of a marked rudimentary structure of the sub-basal dense plaque and the attachment plaque. Focal widening of the lamina lucida suggesting early blistering occurs exclusively in the areas devoid of hemidesmosomes. In separated areas cleavage always occurs in the plane of lamina lucida, viz. the mode of blistering is junctional. Fragments of basal cells are often encountered still remaining attached to the blister floor ("epidermolytic torn-off phenomenon"). These torn-off portions of basal cells are characterized by relatively rich distribution of hemidesmosomes. Basal cells forming the blister roof frequently show small gaps of basal plasma membrane and rarefaction of the basal part of the cytoplasm, which are thought to be secondary changes. Among the observed alterations, structural defects of hemidesmosomes are considered to play the most important role in the pathogenesis of junctional blisters.

Adult↗

Ultrastructural studies in epidermolysis bullosa hereditaria. III. Recessive dystrophic types with dermolytic blistering (Hallopeau-Siemens types and inverse type).

Ultrastructural examination was performed in 42 biopsy specimens from 22 patients with the Hallopeau-Siemens types or with the inverse type of epidermolysis bullosa dystrophica recessiva. The patient group consists of 8 cases of the localized Hallopeua-Siemens type, 9 of the generalized Hallopeau-Siemens type and 5 of the inverse type. The origins of the biopsy specimens are involved, intact and experimentally frictioned skin from blister-predilected sites, as well as clinically normal skin from nonpredilection sites. It is confirmed that all the blisters initiate below the basal lamina. Anchoring fibrils are moderately to markedly decreased in most cases, while they are normal in 3 other cases. It is thought that secondary degradation of anchoring fibrils and/or collagen fibrils plays an important role in blistering mechanism in the Hallopeau-Siemens and inverse types of recessive dystrophic epidermolysis bullosa, whereas a primary aplasia of anchoring fibrils as causative defect has been out ruled.

Collagen↗

Localization of the human GLO gene locus.

Data on the linkage relation between the GLO locus and the HLA, Bf, and PGM3 loci are presented. The family material includes 49 GLO/HLA-B (and/or Bf) segregating matings with 134 children informative on 199 parental meioses. Of phase-known meioses, 3 are recombinants and 75 nonrecombinants; linkage is therefore proven. From the total material a distance of 2.5 cM between GLO and HLA-B/Bf is calculated; and from the segregation in some informative family groups it is shown that GLO is situated between PGM3 and HLA-B/Bf.

Chromosome Mapping↗

Ultrastructural studies in epidermolysis bullosa hereditaria. II. Dominant dystrophic type of Cockayne and Touraine.

Ultrastructural examination was performed in 9 biopsy specimens from 4 patients with the Cockayne-Touraine type of epidermolysis bullosa dystrophica dominans. The specimens were taken from: 1. clinically normal skin from the blister-nonpredilected sites (trunk) as well as 2. atrophic, 3. intact, and 4. experimentally frictioned skin regions from the blister-predilected sites (extremities). In the frictioned skin a dermolytic blister formations was observed. Development of anchoring fibrils showed a marked regional difference, the counts of fibrils being significantly lower (40%) in the predilection sites than in the nonpredilection sites. In addition the anchoring fibrils showed a variable degree of abnormal structure. The low frequency of often abnormally structured anchoring fibrils in the blister-preferred sites provides a good explanation for the clinical features. More studies are needed to see if regional differences in fibril frequency is a feature also of normal skin, in which case the dominant epidermolysis gene may represent a mutated structural anchoring fibril gene.

Connective Tissue↗

Rga (Rodgers) and the HLA region: linkage and associations.

In 19 families with 97 children the segregation of Rga (Rodgers) was found to be compatible with Mendelian inheritance and five backcross and 14 intercross families were found among HLA and Bf typed families. Close linkage (lods + 17.82) without recombination was found between Rg and the HLA region, with a direct count of 96 nonrecombinant meioses for Rg-HLA-B. Rg- was strongly associated with HLA-B8 (29 of 30 haplotypes) and probably associated with Bw40, but did occur on other HLA-B haplotypes. By inference Rg- is negatively associated with Ch- (Chido). The Rg-Ch- haplotype has not been observed. Rga and Cha may or may not be coded for by different sites of the same cistron closely linked to HLA-B:C and cannot as yet be excluded from being parts of B or C.

Blood Group Antigens↗

The Bf locus in the HLA region of chromosome 6: linkage and association studies.

Bf allele frequencies in a material of 172 unrelated Norwegians are given. Bf/HLA linkage relations in 49 informative matings with 178 children, and Bf/HLA association data of a material of 212 Bf-HLA haplotypes are presented. Of 171 informative meioses, there were no Bf-HLA-B recombinations, while 3 out of 158 Bf-HLA-A informative meioses showed recombination. There is significant association between the BfF and the HLA-BW35 allele. It is concluded that the Bf locus is situated on the HLA-B side of HLA-A within the HLA region, in very close proximity to HLA-B.

Alleles↗

On the localization of the Gb locus within the MHS region of chromosome No. 6.

Further data on the Gb - HL-A linkage relationship are presented. All three GBG informative recombinants investigated are Gb - first HL-A recombinants; therefore Gb must be situated on the second HL-A side of the first HL-A locus. Ninety additional apparently Gb - HL-A non-recombinant offspring from 23 matings indicate that the Gb locus is situated in clsoe proximity to the second HL-A locus.

Adult↗