A-raf oncogene localizes on mouse X chromosome to region some 10–17 centimorgans proximal to hypoxanthine phosphoribosyltransferase gene

The localization of the A-rafcellular oncogene on the mouse X chromosome has been determined using Xbal-restricted DNAs prepared from progeny of an interspecies backcross between the B6.CBA.R1 and the Spe/Pas mouse strains. This localization to the proximal part of the mouse X chromosome has been confirmed by the use of somatic cell hybrids, carrying partially deleted X chromosomes and suggests that the A-raf oncogene localizes to a region lying some 10–17 centimorgans proximal to the hypoxanthine phosphoribosyltransferase (Hprt) gene between the locus DXPas4and the locus DXPas7defined by the cross-reacting human X chromosome-specific probe DXS32 (M2C). This localization on the mouse X chromosome is compatible with the presence of the A-rafoncogene on the short arm of the human X chromosome between the centromere and Xp21.     

Autosome and Sex Chromosome Diversity Among the African Pygmy Mice, Subgenus Nannomys (Murinae; Mus)

The African pygmy mice, subgenus Nannomys, constitute the most speciose lineage of the genus Mus with 19 recognized species. Although morphologically very similar, they exhibit considerable chromosomal diversity which is here confirmed and extended by the G-banding analysis of 65 mice from West and South Africa. On the basis of their karyotype and distribution area, the specimens were assigned to at least five species. Extensive differentiation both within and between species was observed that involved almost exclusively Robertsonian translocations, 23 of which are newly described. Two of the rearrangements were sex chromosome-autosome translocations, associated in some cases with partial deletions of the X or Y chromosomes. Several authors have predicted that the highly deleterious effect of this rearrangement would be reduced if the sex and autosomal segments were insulated by a block of centromeric heterochromatin. The C-banding analyses performed showed that among the species carrying X-autosome translocations, one followed the expected pattern, while the other did not. In this case, functional isolation of the sex and autosome compartments must involve other repetitive sequences or genomic traits that require further molecular characterization. Such studies will provide insight into the causes and consequences of the high diversity of sex chromosome rearrangements in this subgenus.     

Unusual site of an embryonal rhabdomyosarcoma of the mesenchymal hepatic pedicle

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of children. Tumors arising in the extrahepatic biliary tree are extremely rare (less than 1% of cases). In this location, most are RMS of the botryoid type. We report a case of a 10-year-old child with embryonal RMS arising in the mesenchyma of the hepatic pedicle. Most tumor cells were large, round with abundant eosinophilic cytoplasm. A few cells were small round or spindle-shaped. Tumor cells showed positive immunostaining for muscle markers: desmin and sarcomeric actin. Electron microscopy revealed 2 types of cells: some were undifferentiated and others showed striated muscle differentiation features.     

Why we prefer the thin layer technique to conventional Pap smears. A double-blind study of 473 specimens

The study evaluated the feasibility of a thinlayer technique on a routine basis for cervical smears and compared 473 ThinPrep preparations to the matched conventional Papsmears. The interpretation was double-blind and performed according to the Bethesda system. A consensus was established in discordant cases. The technique was easily mastered by gynecologists and technicians. Main advantages of the thinlayer technique were: a low number (1%) of unsatisfactory samples; a constant quality; homogeneity of cell distribution; the disappearance of problems of interpretation due to fixation or smear artifacts, red cells, polymorphs; a more precise interpretation, a firmer diagnosis; less visual fatigue; a shorter time of interpretation; the possibility of preparing more slides and performing special techniques on the same specimen. Main disadvantages were a higher cost and a necessary period of learning for cytologists.     

Concentration of zinc, copper, selenium and aluminium in nutritive solutions for parenteral administration]

Total parenteral nutrition (TNP) therapy is widely used. However the quantitative requirements or the toxicity of trace elements in parenteral solutions are difficult to assess. This paper deals with a study performed by the Trace Element Commission of the Société Fran?aise de Biologie Clinique. Trace metals (zinc, copper, selenium and aluminium) which are mainly involved in TPN solutions are analyzed in 12 different parenteral nutrition solutions commercially available. This multicentric assay (5 different sites of analysis) shows that a slight pollution can be noted for nearly all the solutions examined. But at this level (10 mumol/l for the most concentrated solution), the zinc intake cannot induce any toxicity. For copper and selenium the results indicated a negligible pollution. Small-volume solutions added with zinc, copper and selenium are correctly supplemented. As regard aluminium pollution, 4 solutions among 12 contain non negligible amounts of aluminium. The consequences of this TPN overload especially for young infants, indicate that the struggle against this pollution has to be strengthened.     

Partial purification and characterization of B cell growth factor constitutively secreted by human T-cell hybridoma

Human T cell hybridomas were established by fusion of PHA-activated PBL with the 8-azaguanine resistant human T-leukemic cell line CEM-CM3. High levels of B cell growth factor (BCGF) activity were detected in the supernatants of hybridoma C8-2B2 and its subclones. Hybridoma C8-2B2, in addition to the Leu 3a, also expressed the OKT11 surface marker which was not detectable on the parent CEM-CM3 cells. BCGF from the culture supernatant was purified by combined use of salt fractionation and gel filtration to 36.6 fold with 23.9% recovery of activity. The BCGF produced by hybridoma C8-2B2 has a molecular weight range of 16,000–20,000 in two major electrophoretically different forms with pI values of 6.4 and 7.4.     

Serum trace elements and myocardial infarction

The authors report trace elements concentrations (zinc, nickel, selenium, copper, manganese and chromium) during myocardial infarction described in some publication. Serum zinc decreases during the first two days after acute myocardial infarction and returns to normal level in two weeks. Serum nickel increases during the first 36 hours and copper during the first four days. The different explanations of these disturbances are also exposed.