Radiographic images: appearance and reality ( a method of measurement of the 3D coordinates of anatomic points)]

The catch of stereotypes X-ray introduces a conical projection phenomenon which introduce errors from 1 to 5 millimetres. To obtain the real position of anatomical point with precision, we show an original method of co-ordinate 3D calculation which takes account of system radiographic dimensions. A point of space is located compared to the frame of reference of center O (medium of the segment materialized by olives). The frontal stereotype is selected like image of reference after having placed, a 4 mms metal ball on midface of patient. The side stereotype is obtained while making turn the patient of 90 degrees. The axial stereotype is obtained by rotation of the head, around horizontal olives axis. We suppose that the Source-Stereotype unit turns around the patient's head (considered fixed). The protocol comprises a stage of catch of stereotypes X-ray, a stage of digitalization of the sights and initialization of the system and a stage of measurement itself. We describe the setting in equation of real co-ordinate point determination. We apply to the apparent coordinate, the correction formulas we obtain the real co-ordinates of the point.     

A study of 15 cases of primary mediastinal lymphoma of B-cell type.

Fifteen cases of pure supradiapragmatic lymphoma with initial prominent antero-superior mediastinal involvement displaying a B-cell pattern of reactivity were studied. These cases occurred in six men and nine women with a median age of 33 years at diagnosis (range, 23 to 75 years). Supradiapragmatic peripheral lymphadenopathies were present in three cases, and intrathoracic extension to the lung, pericardium, or pleura was possible. In five cases a thymic origin was obvious. All cases exhibited a B-cell pattern of differentiation, with a great variety of histopathologic aspects associated with a high frequency of fibrosis and/or necrosis. Hodgkin's disease was initially misdiagnosed in four cases. The evolution was purely local, with extrathoracic extension in five cases, at the ultimate phase of the disease. The prognosis appeared to be poor with only five patients still alive at a median survival time of 16 months. A complete chemoresistance and radio-resistance was observed in seven cases; only two complete remissions were achieved with aggressive chemotherapy. Prolonged remission could be achieved after surgical reduction of the mass. Primary B-cell mediastinal lymphoma appears to be a distinct clinical entity with local evolution and resistance to therapy. A new therapeutic regimen, which could include surgery in some cases, should be found for this disease.     

Up-regulation of tRNA biosynthesis affects translational readthrough in maf1-delta mutant of Saccharomyces cerevisiae

Maf1p is a negative effector of RNA polymerase III in yeast. The maf1-delta mutation caused an increase in the level of cellular tRNAs, but a decrease of translational readthrough at nonsense codons. Using the lacZ- luc dual gene reporter system, we detected an almost twofold diminution of UAA and UAG readthrough in maf1-delta compared with the parental strain. The maf1-delta mutation did not affect the rate of protein biosynthesis and growth at standard conditions, but resulted in temperature-sensitive growth on non-fermentable carbon sources. We examined the correlation of the temperature sensitive and antisuppression phenotypes of maf1- Delta using a colour phenotype assay in the ade2-1 SUP11 strain. Antisuppression, but not the temperature-sensitive growth defect, was compensated either by increased dosage of SUP11or by [PSI(+)], the prion form of the translation termination factor Sup35p. Summarizing, the elevated tRNA levels in maf1- Delta increase translational fidelity and, independently, affect growth under special conditions.     

Postmitotic differentiation of colon carcinoma caco-2 cells does not prevent reentry in the cell cycle and tumorigenicity

Our purpose was to analyze whether postmitotic Caco-2 colon cancer cells, although they express most of the differentiation characteristics of terminally differentiated intestinal epithelial cells, still maintain, unlike normal cells, a proliferation potential. Experiments were performed with clone TC7 of the Caco-2 cell line. Dividing TC7 cells are undifferentiated and express detectable levels of thymidylate synthase (TS) and cytochrome P450 1A1 (CYP1A1) mRNAs. When reaching confluence TS and CYP1A1 are downregulated, mitosis is no longer detectable, and differentiation takes place, as demonstrated by appearance and increasing levels of differentiation-associated marker mRNAs (e.g., sucrase-isomaltase (SI), dipeptidylpeptidase-IV (DPP-IV) or GLUT5), increasing activities of sucrase and DPP-IV, and increasing expression, on immunofluorescence analysis, of SI on the surface of the cell layer. Trypsinization and seeding of late postconfluent cells (day 30) expressing complete differentiation results within 24 h in upregulation of TS and CYP1A1, a concomitant and dramatic disappearance of differentiation marker mRNAs associated with a decrease in sucrase and DPP-IV activities, and delayed resumption of cell division. This is followed, after the cells have reached confluence again, by downregulation of TS and CYP1A1 and resumption of cell differentiation. The ability of differentiated cells to dedifferentiate was further confirmed by wounding the cell layer of late postconfluent differentiated cultures: within 24 h following the wound, cells migrate from the wound edge and dedifferentiate, as demonstrated by transmission electron microscopy and disappearance of SI from the cell surface of migrating cells. Late postconfluent differentiated cells were tumorigenic in nude mice. These results raise the question of the validity of the concept of differentiation therapy when applied to colon cancer cells.     

Rhabdomyosarcoma and rhabdomyoma associated with nevoid basal cell carcinoma syndrome: Local treatment strategy

This article presents the case of a child presenting with a rhabdomyosarcoma associated with a fetal rhabdomyoma in the setting of nevoid basal cell carcinoma syndrome. Oncologic strategy is discussed.