The role of chromosome 15 in murine leukemogenesis. I. Contrasting behavior of the tumor vs. normal parent-derived chromosomes no. 15 in somatic hybrids of varying tumorigenicity

G-banding analysis was carried out on a series of hybrids derived from the fusion of a chromosome 15-trisomic murine T-cell leukemia of AKR origin and normal diploid fibroblasts or lymphocytes of the CBT6T6 strain. Due to the 14; 15 translocation involved in the generation of the T6 marker, the chromosomes No. 15 and 14 derived from the normal and the tumor parent can be distinguished cytogenetically. Highly tumorigenic, in vitro maintained hybrids, and high-tumorigenic segregants of originally low-tumorigenic in vitro hybrids, selected by in vivo passage, showed a similar cytogenetic pattern. It was characterized by the amplification of the tumor-derived chromosomes No. 15 from the expected 3 to 5.5 ± 0.2 copies and a concomitant decrease of the normal derived T(14;15)6 from 2 copies to 0.9 ± 0.2. All other autosomes except No. 14 showed only minor random variations, around the expected number of 4 copies. The tumor-derived chromosome 14 was amplified from the expected 2 to 3 copies. The lowtumorigenic hybrids showed the opposite pattern with a decrease in the number of the tumor-derived 15 chromosome from 3 to 2.6 ± 0.1 and the maintenance of the two normal parent derived T(14;15)6 chromosomes. These findings suggest the existence of a qualitative difference between the 15 chromosomes derived from the tumor vs. the normal parent, due to mutation or proviral DNA insertion in the tumor-derived homologue. Amplification of the changed locus and a decrease in the dosage of its normal counterpart appear to favor tumorigenicity.     

Representation of whisker follicle intrinsic musculature in the facial motor nucleus of the rat

Retrograde transport of wheatgerm-agglutinin horseradish peroxidase (WGA-HRP) and fluorescent tracers (true blue-TB, nuclear yellow-NY, and diamidino yellow-DY) from isolated whisker follicles was used to define the somatotopic organization of the facial (VII) motoneurons which innervate the intrinsic follicle muscles. Motoneurons supplying these muscles were restricted almost completely to the lateral (Martin and Lodge, '77) facial subnucleus and the motoneurons which innervated a given follicle were distributed over the entire length of this subnucleus. Cells projecting to dorsal (A-row) follicles were located in the most lateral part of the lateral subnucleus, while those supplying ventral (E-row) follicles were restricted to the medial part of the subnucleus. Injections of different tracers into rostral and caudal follicles within a given row revealed no somatotopic representation of the rostrocaudal axis of the whiskerpad. Additional control experiments demonstrated that some of the labelling obtained with WGA-HRP resulted from spread of this tracer to extrinsic muscles. This was not the case with the fluorescent tracers. The results of the control experiments suggested further that a significant percentage of the motoneurons in the lateral facial subnucleus innervate only intrinsic follicle muscles.     

Thorn synovitis: CT diagnosis

A case of monoarticular arthritis due to a retained thorn about the left knee is presented. In this case CT was helpful to localize precisely the thorn within the joint whereas other modalities such as plain films, gallium scan, and 99mTc-methylene diphosphonate bone scan were negative.     

Klippel-Trenaunay syndrome associated with urinary tract hemangiomas.

Genitourinary hemangiomas in 2 children with Klippel-Trenaunay syndrome are reported. The presence of cutaneous hemangiomas should alert urologists to the possibility of urinary tract hemangiomas inpatients with gross hematuria. Transurethral manipulation of bladder hemangiomas should be avoided because of the danger of excessive hemorrhage, the treatment of choice being partial cystectomy.     

Pelvic lipomatosis: diagnosis using computed tomography.

Pelvic lipomatosis is a rare, benign disease in which the characteristic roentgenographic findings may mimic those of pelvic malignancy. In the past more than two-thirds of reported cases have been explored surgically for diagnosis. We present 2 cases to demonstrate how the definitive diagnosis of pelvic lipomatosis can be made with the aid of computed tomography to avoid invasive techniques.