PubMed HealthSearch

Biomedical subjects

G R Stalder

Publications and source records attributed to G R Stalder.

9 recordsLinked to original sources

Calculating genetic risk figures using a programmable pocket calculator.

In autosomal irregular dominant as well as in sex-linked recessive inheritance, heterozygosity probabilities for up to six or eight pedigree members with unknown genotype can easily be calculated using a programmable pocket calculator. The application of the underlying combinatorial programs is explained by means of two relevant examples. Genetic counsellors without a computer at hand are provided with a simple and accurate method for calculating genetic risk figures taking into account pedigree data, incidence and/or mutation rate, reproductive fitness, as well as penetrance or results of heterozygosity tests of the disease in question.

Computers

Loss of the Y chromosome from bone marrow cells of males with myeloproliferative disorders. Report of two cases and review of the literature.

Two additional cases of myeloproliferative disorders are described showing as the only chromosome abnormality a loss of the Y chromosome. Comparing these cases with cases reviewed from the literature indicates that a loss of the Y chromosome in Ph1-positive and Ph1-negative CML may cause only a somewhat longer life expectancy following diagnosis. The exact role of the Y chromosome, however, in the initiation or progression of a malignant disorder cannot be stated at this time.

Adult

Trisomy 8 mosaicism. A case report and a proposed list of the clinical features.

A 16-year-old boy with trisomy 8 mosaicism is presented. Increased birth weight, delayed psychomotoric and accelerated somatic development, and mental retardation were noted; he exhibited a prominent forehead, a broad-bridged upturned nose, an everted lower lip, low set dysmorphic ears, strabismus, slender trunk, narrow pelvis, osseous and joint anomalies, clinodactyly, deep skin furrows on the soles, and agenesis of the corpus callosum. The trisomic cell line was observed throughout the follow-up examinations from the fibroblast cultures between 1962 and 1973, but has disappeared from the lymphocyte culture. The clinical picture of this case is compared with the leading clinical signs and symptoms of the 25 cases with confirmed trisomy 8 so far published. A scheme is proposed in order to keep in mind the clinical picture suggesting trisomy 8.

Abnormalities, Multiple

Editorial: Chromosomes and human neoplasms. Achievements using new staining techniques.

Numerical and structural chromosome aberrations are frequently found in neoplastic cells. As demonstrated by the new chromosome banding techniques these aberrations are not random, but tend to show a specific occurrence. A model example is the leukemias where many cytogenetical investigations have been done to date. In leukemia chromosome analysis serves the following purposes: to identify a neoplastic process, to confirm and strengthen the hematological diagnosis, for the early diagnosis of transformation from a chronic leukemia into its blastic phase and for following up the clonal evolution of a leukemic cell line. In the discussion of chromosomes and neoplasms it must be mentioned that individuals demonstrating chromosomal instability and some trisomic patients show a greater tendency toward the development of a malignancy. Malignancy is primarily a cellular phenomenon caused by a disturbance in cellular regulation, whose fine events are not known. Therefore the exact role of the chromosomes in neoplastic processes cannot be stated. From experimental investigations it appears that the affected chromosomes carry cell growth regulating factors and also that a specific aberration is the result of the action of a specific agent.

Acute Disease

Effect of an ergot derivative on human lymphocyte chromosomes in vivo.

Chromosome examination was made from 12 healthy adult male volunteers by using human lymphocyte cultures twice before, and 8 and 12 weeks after continuous intake of 3 X 1.5 mg Hydergine, an ergot derivative, per day orally. The mean frequency of cells with aberrations and the number of aberrations per 100 cells after 12 weeks' medication corresponded well with those of control cultures. However, for unknown reasons, significantly different values were found after 8 weeks of medication at a level of 5%, i.e., the values of capillary blood culture C8W were lower than those of CI, CII and C12W.

Adult

Satellite DNA III and alkaline Geimsa staining.

Satellite DNA III visualized by staining chromosomes with Giemsa at pH 10-12. Evidence is presented that besides the secondary constriction of chromosome 9, satellite III contained in considerable amount in the long arms of chromosome 20, giving rise to a clearly visible secondary constriction just below the centromere. The latter finding confirms that reported by Bobrow et al. (1972). The long arms of the Y chromosome also show strong staining with alkaline Giemsa, the region of staining corresponding exactly with the intensely flourescing area. This is interpreted as possible evidence for the presence of satellite DNA III in the distal long arms of the human Y chromosome.

Chromosomes

[45,X/46,SYq dic-Sexchromosome mosaic].

This is the report on an obese girl with small stature and sexual infantilism. A 45,X/46,XYq dic mosaic was found in blood and fibroblast cultures. A summary is given of the cases so far reported in the literature. The clinical picture does not differ significantly from that of 45,X/46,XY cases. The relationship of phenotype and structural abnormalities of the Y chromosome is discussed.

Adult