Chromosome abnormalities in peripheral T-cell lymphoma.

We have studied neoplastic lymph nodes from six patients histologically, immunologically and cytogenetically. Histologically all the cases were classified as peripheral T-cell lymphomas. These were subclassified as T-zone lymphomas in three, large cell 'pale cell' variant in one, large cell immunoblastic in one, and small cell, mycosis fungoides in one. Two had features of angioimmunoblastic lymphadenopathy (AILD). Immunologically all cases expressed CD2 (OKT11) and CD4 (T4). All six cases had clonal chromosome abnormalities, although in four cases the majority of cells were chromosomally normal. Chromosome 3 was most often involved in abnormalities, occurring in five patients. The most common single chromosome abnormality, trisomy 3, was seen in all three cases classified as T-zone lymphoma and in no other cases. In the two cases with features of AILD only numerical abnormalities were seen, whereas in the other cases complicated structural rearrangements were present. Recurring structural abnormalities involved bands 1p12or13, 1q32, 3p25 and 14q11. Our data suggest that cytogenetic analysis may assist in diagnosis and classification of the peripheral T-cell lymphomas.

Reaggregates of cells from rat testis resemble developing gonads.

Reaggregates prepared from newborn rat testis cells in Moscona-type rotation cultures were analyzed and compared with normal fetal (12-21 days) and newborn testes at the light and electron microscope level. After 25 h of culture, the aggregates resembled normal testicular tissue. The cells of the surface layer were spindle-shaped and connected by adherent junctions. The epithelial cords were composed exclusively of Sertoli cells and were surrounded by elongated cells resembling the developing myoid cells in newborn testes. The basal aspect of the cords was covered by a layer of flocculent material which, in places, was organized like an ordinary basement membrane. Individual spermatogonia with pseudopodes were observed in the interstitial tissue. Some Leydig cells were organized into small clusters like those typical in newborn testes. The present observations indicate that, histologically, the reaggregation of separated testicular cells resembles the differentiation of embryonic male gonads.

Chromosome abnormalities in 16 Finnish patients with Burkitt's lymphoma or L3 acute lymphocytic leukemia.

Eleven patients with Burkitt's lymphoma (BL), i.e., small noncleaved non-Hodgkin's lymphoma, and 5 patients with Burkitt-type acute lymphocytic leukemia (ALL-L3) were selected for chromosome study. Two of the 16 patients had no B-cell markers, but the erythrocyte marker--glycophorin A--was present on the surface of the leukemic blasts. The critical breakpoint at 8q24 was detected in 14 of the 16 patients, whereas this aberration was not detected in any of the 134 patients belonging to other subgroups of non-Hodgkin's lymphoma or ALL that we studied during the same period. In addition to the t(8;14)(q24;q32), the following translocations with the breakpoint at 8q24 were seen: t(2;8)(p11;q24), t(8;11)(q24;q13) in BL, and t(2;8;14)(p11 or p12;q24;q32) in ALL. Additional aberrations seen more than once were trisomy #7 and abnormalities in chromosomes #1, #11, and #13.

Morphogenesis and fibronectin in sexual differentiation of rat embryonic gonads.

The possible role of fibronectin in the organization of the sex-specific gonadal components was studied by immunocytochemistry combined with electron and light microscopy in rat fetuses at the ages of 12-15 days. Fibronectin was evenly distributed in both sexes under the basal lamina of the surface epithelium. Other basal laminae were not seen using light or electron microscopy inside the gonadal ridges at the age of 12 days. As the first sign of sexual differentiation, fibronectin-negative gonadal cords appeared in 13-day-old fetuses. In the males the cords were bigger than those in the females. The cords were clearly separated from the interstitium in 15-day-old fetuses of both sexes. A continuous layer of fibronectin had formed between the testicular surface epithelium and the elongated cords indicating the formation of a tunica albuginea. In females the surface epithelium-cord connection was maintained at all stages. Connections of the gonadal cords to mesonephric tubuli were seen in the rete region of both sexes. The electron optical basal lamina around the gonadal cords became continuous by the age of 15 days. The present results suggest that fibronectin is intimately involved in the sexual differentiation of the gonads, but not under the regulation of H-Y antigen or other testis-organizing factor.