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Biomedical subjects

J German

Publications and source records attributed to J German.

At least 109 records · Page 6Linked to original sources
PubMed1975

A patient with the Larsen syndrome.

A child with the Larsen syndrome is described. His multiple malformations included a flattened nasal bridge and other unusual facial features, a cleft palate, a poorly developed larynx and dislocations involving several joints.

Abnormalities, Multiple↗
PubMed1974

Mapping human autosomes: evidence supporting assignment of rhesus to the short arm of chromosome No. 1.

Rh-negative erythrocytes were found in the blood of an Rh-positive man suffering from myelofibrosis. Nucleated hemopoietic precursors were also circulating in his blood, and these cells had an abnormal chromosome complement from which identifiable chromosome segments had been deleted. Correlation of the serological and cytogenetic findings, combined with previous data, indicates that the Rhesus blood group locus is on the distal portion of the short arm of chromosome No. 1.

Chromosome Aberrations↗
PubMed1974

A manyfold increase in sister chromatid exchanges in Bloom's syndrome lymphocytes.

Dividing cells from persons with Bloom's syndrome, an autosomal recessive disorder of growth, exhibit increased numbers of chromatid breaks and rearrangements. A highly characteristic feature of the chromosome instability in this syndrome is the tendency for exchanges to occur between chromatids of homologous chromosomes at homologous sites. In the present experiments, a cytogenetic technique by which the sister chromatids of a metaphase chromosome are stained differentially has been used to demonstrate a striking and possibly specific, but hitherto unrecognized, increase in the frequency with which sister chromatids also exchange segments. The cells were grown in bromodeoxyuridine and stained with 33258 Hoechst and Giemsa. Whereas phytohemagglutinin-stimulated lymphocytes from normal controls had a mean of 6.9 sister chromatid exchanges per metaphase (range 1-14), those from persons with Bloom's syndrome had a mean of 89.0 (range 45-162). Normal frequencies of sister chromatid exchanges were found in cells heterozygous for the Bloom's syndrome gene, and also in cells either homozygous or heterozygous for the genes of the Louis-Bar (ataxia telangiectasia) syndrome and Fanconi's anemia, two other rare disorders characterized by chromosome instability. In a differentially stained chromatid interchange configuration discovered during the study, it was possible to determine the new distribution of both sister and non-sister-but-homologous chromatids that had resulted from numerous exchanges. By following shifts in the pattern of staining from chromatid to chromatid, visual evidence was obtained that the quadriradial configurations long recognized as characteristic of Bloom's syndrome represent exchanges between homologous chromosomes, apparently at homologous points. We postulate that the increase in the frequency of exchanges between nonsister-but-homologous chromatids and those between sister chromatids in Bloom's syndrome represents aspects of one and the same disturbance. A study of this phenomenon in relation to the clinical features of Bloom's syndrome may be helpful eventually in understanding the biological significance of chromatid exchange in somatic cells.

Abnormalities, Multiple↗
PubMed1974

The Roberts syndrome.

The Roberts syndrome appears to follow an autosomal recessive mode of inheritance. The cause of the abnormalities probably exerts its effect prior to the seventh week of gestation and only on a few organ systems undergoing development during this time. The peculiar morphologic features of metaphase chromosomes of the one individual who has been studied extensively are unexplained.

Abnormalities, Multiple↗