Hypermutability of mouse chromosome 2 during the development of x-ray-induced murine myeloid leukemia

In an effort to identify the precise role of a deletion at regions D-E of mouse chromosome 2 [del2(D-E)] during the development of radiation-induced myeloid leukemia, we conducted a serial sacrifice study in which metaphase chromosomes were examined by the G-banding technique. Such metaphase cells were collected from x-irradiated mice during the period of transformation of some of the normal hematopoietic cells to the fully developed leukemic phenotype. A group of 250 CBA/Ca male mice (10-12 weeks old) were exposed to a single dose of 2 Gy of 250-kilovolt-peak x-rays; 42 age-matched male mice served as controls. Groups of randomly selected mice were sacrificed at 20 hr, 1 week, and then at intervals of 3 months up to 24 months after x-irradiation. Slides for cytogenetic, hematological, and histological examination were prepared for each animal at each sacrifice time. An expansion of cells with lesions on one copy of chromosome 2 was evident in 20-25% of treated mice at each sacrifice time. The majority of such lesions were translocations at 2F or 2H, strongly suggesting hypermutability of these sites on mouse chromosome 2. No lesions were found in control mice. The finding leads to the possibility that genomic lesions close to 2D and 2E are aberrants associated with radiation leukemogenesis, whereas a single clone of cells with a del2(D-E) may lead directly to overt leukemia. The data also indicate that leukemic transformation arises from the cumulative effects of multiple genetic events on chromosome 2, reinforcing the thesis that multiple steps of mutation occur in the pathogenesis of cancer.     

The National Cancer Data Base report on the relationship of race and national origin to the histology of nasopharyngeal carcinoma

This study was undertaken to clarify several aspects of morphological and taxonomic characters of Physaloptera bispiculata Vaz and Pereira, 1935, a parasite of the water rat, Nectomys squamipes. The cephalic structures (including lips, papillae, teeth, amphids, and porous areas) and details of the posterior end of male and female adult worms were examined by scanning electron microscopy, leading to the addition of new taxonomic characters for this species. We consider P. bispiculata a valid species, based on a comparative analysis of the specific characters for P. bispiculata and P. getula Seurat, 1917, including the morphology and morphometry of body structures as well as number and disposition of caudal papillae of the males.     

Lens transmission by fluorophotometry after brachytherapy and thermotherapy of choroidal melanoma

We studied the effect of transpupillary thermotherapy (TTT) by a diode laser at 810 nm combined with episcleral ruthenium-106 plaque treatment (106Ru) on lens transparency in patients with choroidal melanoma. Lens transmission of blue-green light was measured by fluorophotometry in 17 patients treated with 106Ru treatment and TTT (measured 0.36 years after treatment), 12 patients treated with 106Ru alone (measured 19 years after treatment) and 25 age-matched healthy controls. Differences in lens transmission were not significant between treated and untreated fellow eyes (p > 0.15) nor between patient and control eyes (p > 0.25). TTT of choroidal melanoma combined with 106Ru plaque irradiation did not have a significant effect on the lens transparency up to 6 years after treatment.     

The 9E3/CEF4 gene product is a chemotactic and angiogenic factor that can initiate the wound-healing cascade in vivo

The chicken gene 9E3/CEF4 codes for a 9-kDa protein that belongs to the C-X-C family of chemokines. This gene is stimulated to high levels by thrombin, and is overexpressed in the granulation tissue of wounds, especially in areas of neovascularization, suggesting that it is importantly involved in wound healing. The authors used the Chorioallantoic Membrane (CAM) assay to examine experimentally the functions of the 9E3 chemokine in vivo. It was shown that at lower doses this protein is chemotactic for monocyte/macrophages and lymphocytes (but not heterophils), and directly or indirectly stimulates the growth of blood vessels towards the pellet containing the protein, causes hyperproliferation of the ectoderm of the CAM, and formation of a tissue that resembles the granulation tissue of wounds. At higher doses, however, it does not stimulate chemotaxis of leukocytes but instead causes the blood vessels of the CAM to undergo sprouting. It was also shown that this protein is found in the endothelial cells of developing blood vessels but not in those of mature blood vessels and that, in the latter, expression can be stimulated by application of agents that cause inflammation or are known to be angiogenic. Because the product of the 9E3 gene has chemotactic and angiogenic properties, it is proposed that it be called the chicken Chemotactic and Angiogenic Factor (cCAF). These observations show that in the absence of wounding, cCAF, by itself, can initiate a complex series of events that strongly resemble those involved in the immune response and granulation tissue formation, suggesting an important role for this and related chemokines in wound healing. Although this chemokine belongs to the C-X-C family it can perform functions of both the C-C (chemotaxis for monocyte/macrophages and lymphocytes) and C-X-C (angiogenesis) families, suggesting that this could be the first of a functionally broader family of chemokines which would be generated as a response to emergency situations.