Ionizing radiation is a well known risk factor of thyroid cancer development, but the mechanism of radiation induced carcinogenesis is not clear. The RET/PTC oncogene, an activated form of the RET proto-oncogene, is frequently observed in papillary thyroid carcinoma (PTC); RET/PTC1, -2 and -3 are known to be the three major forms. High frequencies of RET/PTC rearrangements have been observed in radiation-associated PTC, such as those appearing post-Chernobyl or post-radiotherapy, but the rearrangement types dier between these two populations. We investigated whether a speci®c type of RET/PTC rearrangement was induced by X-rays in vivo and in vitro. In human normal thyroid tissues transplanted in scid mice, the RET/PTC1 rearrangement was predominantly detected throughout the observation period (up to 60 days) after X-ray exposure of 50 Gy. On the other hand, RET/PTC3 was detected only 7 days after X-irradiation, and no transcript of RET/PTC2 was detected. These results are supported by the results of an in vitro study. The RET/PTC1 rearrangement was preferentially induced in a dose-dependent manner by X-rays within a high dose range (10, 50 and 100 Gy) in four cell lines. On the other hand, RET/PTC3 was induced at a much lower frequency, and no induction of RET/PTC2 was observed. These results suggest that the preferential induction of the RET/PTC1 rearrangement may play an important role in the early steps of thyroid carcinogenesis induced by acute X-irradiation. Oncogene (2000) 19, 438 ± 443.

The SC rate of VSD by mean age of 6.9 years was 48%, but it was 72% in patients without CHF. In patients with CHF, SC was seen only in patients with a perimembranous VSD. The rate of SC was 10% in subpulmonary VSD. The authors contend that SC probably occurred by growth of muscular septum surrounding VSD. Muscular VSD spontaneously closed earlier than perimembranous VSD.

We examined the etiology of a long-term postoperative complication, pulmonary arteriovenous malformation (PAVM), in a patient who underwent total cavopulmonary shunt (TCPS). The patient underwent TCPS at the age of 3 years and 1 month, and a PAVM developed. At the age of 10 years, TCPS was switched to total cavopulmonary connection to facilitate circulation of hepatic venous blood to the pulmonary artery. As a result, oxygen saturation increased. These findings suggest that the absence of pulmonary circulation of hepatic venous blood is involved in the development of PAVM.

Metaphase chromosome configurations of 23 species and subspecies belonging to five subgroups of the immigrans species group of Drosophila were examined by the Giemsa staining method, from the point of view of the phylogenetic relationships in this species group.New to science are the descriptions of the karyotypes of five species, Taxon-C, Taxon-F, D, nivei f rons,, D. quadrilineata and D, neohypocausta which are 2n=8, 2R+1V+1D; 2n=8, 2R+1V+1D; 2n=8, 2R+1V+1D; 2n =12, 4R+ 1V+ 1D; and 2n = 6, 2R+ 1V, respectively.The karyotypes of the other species were also examined and compared with earlier descriptions. Some of our observations agreed with earlier ones but the remainder showed some major or minor differences from the previous reports.The basic karyotype of the species belonging to the immigrans species group was 2n=8, 2R+1V+1D (or short rod). The karyotypes of D. annul ipes and D. quadrilineata of the D. quadrilineata subgroup, of D, argentostriata and D, silvistriata of the D, lineosa subgroup and of D, neohypocausta of the D. hypocausta subgroup differed fundamentally from the basic type of the immigrans species group. These five species might be somewhat remote from the other species of the immigrans group.Some species exhibited intraspecific variations among the forms of the Y chromosome and Chromosome 4, with additional heterochromatin.In the D. nasuta subgroup, it seemed that fusions were important factors in their evolution. D, albomicans is the most advanced species, and from considerations of morphological similarities, results of hybridization tests, karyotypes, and geographical distribution, D, nasuta is the most plausible species from which D, albomicans originated. D, albomicans collected from the Chiangmai population in Thailand had supernumerary chromosomes, the most peculiar phenomenon among the karyotype variations of the immigrans species group. These chromosomes may be maintained consistently in this population.

SUMMARY In a patient with Turner mosaicism who had mental retardation, epilepsy and cerebellar ataxia, MRI showed cerebellar atrophy and a bizarre cortical dysgenesis of the cerebrum, which was considered to comprise a mixture of relatively normal gyri and structures resembling pachygyria and Iissencephaly. The karyotype of the patient was 45.X/47.XXX, but the brain dysgenesis could not be explained solely on the basis of this mosaicism, which is rarely associated with a gross abnormality in brain pathology. Abnormality of the X chromosome seems to have some potential for inducing cortical dysgenesis, and this case may be partially attributable to an abnormal locus on the X chromosome. RÉSUMÉ Dysgénésie corticale chez un sujei avec un Turner mosaïque Chez un patient avec Turner mosaïque présentant un retard mental, une épilepsie et une ataxie cérébelleuse, l'IRM révéla une atrophie cérébelleuse et une dysgénésie corticale bizarre du cerveau, qui fut considérée comme un mélange d'un gyrus relativement normal et de structures ressemblant à une pachygyrie et une lissencéphalie. Le caryotype du patient était 45,X/47,XXX, mais la dysgénésie cérébrale ne pouvait pas étre expliquée seulement par la mosaïque, rarement associée à une anomalie sévère dans la pathologie cérébrale. L'anomalie du chromosome X semblc présenter un potentiel d'induction de la dysgénésie corticale, et ce cas peut étre partiellement attribuable à un locus anormal du chromosome X. ZUSAMMENFASSUNG Kortikale Dysgenesie bei einem Patienten mil Turner Mosaik Bei einem Patienten mit Turner Mosaik mit geistiger Retardierung, Epilepsie und cerebellärer Ataxie fand sich im MRI eine cerebelläre Atrophie und cine seltsame kortikale Dysgenesie des Gehirns, was als eine Mischung aus relativ normalen Gyri und Strukturen wie bei der Pachgyrie und Lissenzephalie angesehen wurde. Der Karyotyp des Patienten war 45, X / 47, XXX, aber die Dysgenesie ließ sich nicht nur auf der Basis dieses Mosaiks erklären, da bei diesem selten auffällige Anomalien in der Hirnpathologie auftreten. Durch eine Anomalie des X Chromosoms könnte eine kortikale Dysgenesie hervorgerufen werden, und dieser Fall könnte einem abnormen Locus auf dem X Chromosom zugeschrieben werden. RESUMEN Dysgenesia conical en un paciente con mosaicismo de Turner En un caso de mosaicismo de Turner con retraso mental, epilepsia y ataxia cerebclosa. la IRM mostró una atrofia cercbelosa y una disgenesia cortical rara que comprendía una mezcla de circulvoluciones relativamerite normales y estructural que semejaban paquigiria y lisencefalia. El cariotipo del caso era 45.X/47.XXX, pero la disgenesia cerebral no podía ser expresada nicamente sobre la base del mosaicismo, que raramente va asociado a anomalias groseras del cerebro. La anomalia del cromosoma X parece tener una capacidad para inducir una disgenesia cortical y este caso puede ser parcialmente atribuible a un locus anomalo en el cromosoma X.