Accelerated Appearance of Skin Tumors in Hairless Mice by Repeated UV Irradiation with Initial Intense Exposure and Characterization of the Tumors

Skin tumors were produced on the back of hairless mice, HOS (HR/De), by exposure to ultraviolet B light (UVB, 290–320 nm) with 4 different protocols. The first tumors appeared earlier (in 10 weeks in group I and 7 weeks in group III) when initial intense exposure was given, followed by repeated lower-level exposures, than when the mice were exposed to the repeated UV only (in 16 weeks both in group II and group IV). All mice developed skin tumors earlier in the groups given the repeated UV exposures three times a week than in the groups given the exposures twice a week. Most of the skin tumors produced by the UVB exposure were histologically malignant, being transplantable to nude mice, and the cultured cells grown from the tumors were capable of producing tumors when injected into nude mice. The accelerated development of skin tumors by initial intense exposure and short intervals of repeated exposure observed in this study may have implications for humans who expose themselves to intense sunbathing and UV tanning (burning) by fluorescent sun lamps.     

A case of antiphospholipid syndrome associated with left subclavian artery thrombosis and left external iliac vein thrombosis]

Arterial thrombosis is one of the major symptoms of antiphospholipid syndrome (APS). However, thrombosis in a primary branch of the aorta has rarely been reported in APS. We report here a case of APS complicated by thromboses in both the left subclavian artery and the left external iliac vein. A 32-year-old woman was admitted in May, 1990 complaining of no pulse in the left superficial arteries (e.g., left radial artery) for the past 5 years and acute swelling of the left lower extremity. A left ascending phlebography showed an occlusion of the external iliac vein and arteriography revealed obstruction in the left subclavian artery. Collateral circulations were developed at the site of each thrombus. Clotting and immunological studies revealed a prolonged APTT, a high titer of anticardiolipin antibody and lupus anticoagulant positive. We ruled out various diseases and clinical risk factors predisposing to both arterial and venous thromboses. Accordingly, we concluded that both thromboses were based on APS. Following treatment with anticoagulants, aspirin and corticosteroid, the swelling of her left thigh was diminished and the antibody titer was decreased within 3 months.     

Hemangioma of the Prostatic Urethra: Hematospermia and Massive Postejaculation Hematuria with Clot Retention

The case of a 53-year-old man with hematospermia and massive postejaculation hematuria that caused urinary retention is described. This is the sixth case in the English and Japanese language literature. Cystourethroscopic examination revealed that a solitary raised tumor was present just distal to the vermontanum, and that bleeding was from its apex. Histologic examination of an excisional biopsy sample showed features compatible with hemangioma.     

Uveitis and immune responses in primates immunized with IRBP-derived synthetic peptides

Monkeys immunized with bovine IRBP-derived synthetic peptides R4 (sequence 1158-1180) or R14 (1169-1191) developed EAU which was detected by both clinical and histological examinations. The inflammation localized mainly in the choroid, with only minor changes being noticed in the adjacent retinal tissue. EAU developed in only one of the two monkeys immunized with each of the peptides and the animals with disease also showed higher levels of cellular immunity toward the immunizing peptide than did the monkeys with no disease. The cellular immune responses, measured by the lymphocyte proliferation assay, were specific toward the immunizing peptides, with no cross responsiveness to whole IRBP. This finding suggests that the two uveitogenic peptides were non-immunodominant in the tested monkeys. In contrast, peptide R14 is highly immunodominant in the Lewis rat. Also, the fine specificity of the monkey response to R14 differed from that of the Lewis rat. The possible genetic control of the monkey susceptibility to EAU induction by the peptides is discussed and the unique finding of an autoimmune disease induction by a non-immunodominant peptide is underscored.     

Determination of the exposure concentration of propylene oxide to produce neuropathy in rats

Although propylene oxide, which is similar in chemical structure to ethylene oxide, is expected to produce neuropathy, there is no convincing evidence of the degeneration of the peripheral nervous system. To determine the exposure concentration of propylene oxide necessary to produce neuropathy in male Wistar rats, we subjected them to repeated exposures of propylene oxide at concentrations of 500, 750, 1000, 1500 and 2000 ppm. The test rats were subjected to a single 6 hour exposure of propylene oxide at a concentration of 1500 parts per million 5 times a week for 3 weeks. They developed a significant decrease in body weight, abnormal posture of the hindlegs and axonal degeneration of myelinated fibers in the peroneal and sural nerves, the nerves to the soleus muscle, and in the fasciculus gracilis of the spinal cord. Therefore, it was concluded that propylene oxide induces neuropathy in rats characterized by axonal degeneration, similar to that produced by ethylene oxide, and that the exposure to the higher concentration of propylene oxide is more necessary to produce neuropathy than in the case of ethylene oxide neuropathy in rats.     

Enhancement of the cytotoxicity of cytosine arabinoside by interleukin-3.

We have evaluated the feasibility of enhancing the cytotoxic effect of cytosine arabinoside (ara-C) on acute myeloid leukemia (AML) cells by increasing the proliferative activity with hematopoietic growth factors. Leukemic cells from 8 persons with AML were tested. Preincubation with interleukin (IL)-3 (5 U/ml) for 3 days increased DNA synthesis as measured by tritiated thymidine incorporation and Ki67 expression in cells from 7 out of 8 persons with AML. Leukemic cells preincubated with IL-1 (10 U/ml) or IL-3 (5 U/ml) were subsequently exposed to ara-C (3 micrograms/ml) for the final 24 h and the activity of ara-C against clonogenic acute myeloid leukemia cells was evaluated in terms of the inhibition of colony formation in semisolid media. The exposure to ara-C inhibits the proliferation of a higher proportion of clonogenic cells in culture pretreated with IL-3 than in control or cells pretreated with IL-1. The enhanced cytotoxic effect of ara-C in the cells pretreated with IL-3 correlated with increased formation of intracellular ara-CTP. IL-3-induced recruitment of quiescent blasts into the proliferative compartment will lead to increased formation of ara-CTP in the cells, which would result in an enhanced leukemia cell kill.