Biomedical subjects

G Dewald

Publications and source records attributed to G Dewald.

8 recordsLinked to original sources

PubMed1979

[C6-polymorphism of the sixth component of complement: application to paternity cases (author's transl)].

The results of a study of the polymorphism of the sixth component of human complement by means of isoelectric focusing in polyacrylamide gels with subsequent C-dependent lysis in an agarose overlay containing C6 deficient rabbit serum are reported. The allele frequencies obtained (C6A = 0.613, C6B = 0.379, C6R = 0.008) are in good agreement with those previously published. The mode of inheritance in 47 families with 173 offspring as well as 26 mother-child combinations is in agreement with a formal genetical model: "C6A, C6B, C6A1 and C6B1 at an autosomal locus". The inclusion of this system into a blood group expertise in Germany can be recommended.

Adult↗

PubMed1979

Polymorphism of the second component of human complement (C2). Observation of the rare phenotype (C2 2 (= C2 B) and data on the localization of the C2 locus in the HLA region.

The polymorphism of the second component of human complement was studied by means of isoelectric focusing in polyacrylamide gels with subsequent complement-dependent lysis of sensitized sheep erythrocytes in an agarose overlay containing C2-deficient or normal human serum. In a material of 289 unrelated individuals the following gene frequencies were observed: C21=0.965 and C22=0.035. The rare phenotype C2 2 (=C2 B) could be seen once in a child of a C2 1--2 heterozygous mother. The investigation of the C2/HLA relationship revealed a very close linkage: Among 62 informative meiotic divisions one recombination between HLA-B and C2 was found (i.e. 1.61%); in addition, C2(2) was significantly associated with HLA-B15 and -Cw3. In a family with an HLA-B/D(DR) crossover C2 segregated together with HLA-D(DR). This supports the assumption of a C2 structural locus outside HLA-B, probably near HLA-D(DR).

Alleles↗

PubMed1978

Replication patterns of three isodicentric X chromosomes and an X isochromosome in human lymphocytes.

Chromosomes from four patients with variants of the Turner syndrome were investigated by G- and C-bandind and DNA replication techniques. Their karyotypes were: 1) 46,X,idic(X)(q28), 2) 45,X/46,X,idic(X)(q24), 3) 45,X/46,X,idic(X)(p11), and 4) 46,X,i(Xq). In patients 1, 2, and 3, the abnormal X was isodicentric, with different break-and-fusion points in each case. In each, the G-band pattern on one side of the breakpoint was a mirror image of that on the other side. Each had two distinct C-bands, only one of which was associated with a primary constriction. The fourth patient had an isochromosome of the long arm of an X in which only one C-band could be discerned. Replication studies were done on lymphocyte cultures by incorporating a thymidine analogue and staining with acridine orange. In addition, replication patterns of normal early- and late-replicating X chromosomes were studied in two normal females. In the four patients, all the normal X chromosomes had normal early-replication patterns. The two idic(X) chromosomes with break-and-fusion points on their long arms almost always had symmetric replication patterns, which demonstrates that the corresponding bands replicated synchronously. In contrast, many of the idic(X)(p11) and i(Xq) chromosomes showed asymmetric or asynchronous replication. In each, the replication pattern of the abnormal X was similar to the equivalent portions of a normal late-replicating X.

Adolescent↗

PubMed1978

Sister chromatid exchanges in Bloom's syndrome.

The importance of chromosome instability in Bloom's syndrome is reviewed, and the recently developed technique for demonstrating sister chromatid exchanges (SCE) is described. In Bloom's syndrome, but not in other heritable syndromes associated with chromosome instability, there is a nine- to ten-fold increase in the frequency of spontaneous SCE. We present a case of Bloom's syndrome in which this test facilitated the diagnosis. In four obligate heterozygotes (the parents of children with Bloom's syndrome), however, an increase in the frequency of spontaneous SCE was not observed.

Abnormalities, Multiple↗

PubMed1977

Exclusion of the HLA locus from a large portion of the long arm of chromosome 6.

HLA antigens were determined in two infants with multiple congenital anomalies and in their healthy parents and one sibling. One infant had a deletion of a major portion of the long arm of chromosome 6. The other child had a translocation of a similar piece of chromosome 6 to the short arm of chromosome 3. The mother and the maternal grandmother showed this translocation in a balanced state. The HLA types of both children and their parents exclude the localization of the major histocompatibility locus from the deleted or translocated portion of the long arm of chromosome 6.

Abnormalities, Multiple↗

PubMed1977

Failure of inactivation of Duchenne dystrophy X-chromosome in one of female identical twins.

Duchenne muscular dystrophy manifested in one of girl twins. The twins were monozygous on the basis of red cell and HL antigens and skin graft compatibility. Karyotyping, including banding techniques, showed a normal number of chromosomes and a normal configuration of the X-chromosome in both twins. The twins were identical in appearance until symptoms of Duchenne dystrophy developed in one at age 4 years. The maternal uncle had classic Duchenne dystrophy; the mother and the nonmanifesting twin showed evidence of being heterozygous for Duchenne dystrophy. The phenotypic difference in monozygous twins is readily explained by lyonization of the X-chromosome after twinning has occurred. The findings substantiate the existence of Duchenne dystrophy manifesting in females with normal karyotypes.

Child↗

PubMed1976

Usefulness of chromosome examination in the diagnosis of malignant pleural effusions.

To determine whether chromosome analysis could facilitate the diagnosis of malignant pleural effusions, we examined chromosomes in effusions from 104 unselected patients. An effusion was regarded as malignant if at least three of 30 metaphase cells were hyperdiploid or contained a marker chromosome. Results were compared with standard cytologic diagnoses. All 22 benign effusions were diagnosed correctly by cytologic examination, but one nosed correctly by cytologic examination, but one (acute rheumatoid lung disease) was misclassified as positive by chromosome criteria. Of the 82 malignant effusions, 53 (65 per cent) were diagnosed correctly by cytologic tests, as compared with 58 (71 per cent) by chromosome analysis (P greater than 0.2). Among patients with malignant neoplasms, 13 had leukemia or lymphoma; only four of these (31 per cent) were diagnosed by cytologic tests as compared with 11 (85 per cent) by chromosome analysis (P less than 0.01). The combination of standard cytologic and chromosome analyses correctly identified 83 per cent of the neoplasms, a result significantly better than that with either technic alone (P less than 0.01).

Aged↗

PubMed1975

A diploid-triploid human mosaic with cytogenetic evidence of double fertilization.

The karyotype 46,XX/69,XXY was found in a 13-year-old mentally subnormal patient with club feet, strabismus, eunuchoid habitus, small penis, midscrotal urethrovaginal opening, small descended left testis, and small undescended right testis; no ovarian tissue could be found at laparotomy. Triploid:diploid cell ratios were 60:40 and 4:96 in skin fibroblasts and curculating lymphocytes, respectively. In the triploid line, two of the no. 13 chromosomes had unusually large satellites and one of the no. 22 chromosomes had a brightly fluorescent zone on its short arms. The patient's father was heterozygous for both these autosomal markers; the mother carried neither marker. This, together with the single Y, indicated that the extra haploid set was derived from the father. Of several possible mechanisms, we favor the suggestion that double fertilization occurred; one sperm nucleus immediately fused with the egg nucleus producing the diploid line; the second sperm nucleus was incorporated later into one of the two cells resulting from the first division of the zygote, producing the triploid line.

Adolescent↗