[Role of karyotype in studying male infertility].

The karyotype of 443 infertile males has been studied (infertility of unknown etiology). The sample has been divided in 3 groups according to the data of their spermogram: Gr 1--101 males with a normal spermogramm (selected through the sterility of their couple). Gr 2--185 infertile males with oligospermy (less than 20 millions spermatozoal/ml).

[Reciprocal translocation at the origin of a Robertsonian translocation 15;22 by the loss of a metacentric chromosome. Genetic counseling].

One of the children of a t(15;22) (q111;p11) woman has lost the minute metacentric der(15) without any clinical consequence, indicating the inocuity of the 15pter----q111 and 22pter----p11 monosomies. The segregation mechanism of this monosomy and, from this family, the relation between reciprocal translocations and Robertsonian translocations are discussed. Another subject with r(22) in the same family questions on an hypothetic common origin.

[Cytogenetic analysis of the Bloom syndrome. A study of the exchange-break relationship].

Cytogenetic study of a case of Bloom's syndrome (number 46 of the international registry) confirms the excess of exchanges in all cellular types with the exception of a minority of lymphocytes and of two lymphoblastoid cell lines. These exchanges are produced in an X or U fashion between sister chromatids or between homologous chromatids and produce both simple and complex figures for which symmetry is the common feature. Some of these structures are rearranged secondarily, producing centric or acentric fragments and marker chromosomes.

[Small cell epithelioma in the Rhône-Alp region: changes in incidence between 1970 and 1980].

4 856 cases of primary lung carcinoma in the Rhônes-Alpes area have been collected from 1970 to 1980 by cytological examination. The validity of these data rests upon the fact that they come from the same laboratory. The percentage of small cell carcinomas has been calculated per year and per geographical area.