High incidence of meningioma among Hiroshima atomic bomb survivors.

Since the atomic bomb explosions in Hiroshima and Nagasaki, high incidences of leukemia, thyroid cancer and other tumors have been reported as atomic bomb-induced tumors. We investigated the incidence of meningioma among Hiroshima atomic bomb survivors. Sixty-eight patients surgically treated for meningioma who had been within 2.0 km of the hypocenter of the explosion were identified. Six hundred and seven non-exposed patients with meningioma were also studied. Treatment dates were from 1975 to 1992. The incidences of meningioma among 68 subjects within 2.0 km and 607 non-exposed patients were 8.7 and 3.0 cases per 10(5) persons per year, respectively. The incidences of meningioma among the survivors of Hiroshima in 5-year intervals since 1975 were 5.3, 7.4, 10.1, and 14.9, respectively. The incidences of meningioma classified by distances from the hypocenter of 1.5-2.0 km, 1.0-1.5 km and less than 1.0 km were 6.3, 7.6 and 20.0, respectively. The incidences of meningioma classified by doses to the brain of 0-0.099 Sv, 0.1-0.99 Sv and more than 1.0 Sv were 7.7, 9.2 and 18.2, respectively. The incidence of meningioma among Hiroshima atomic bomb survivors has increased since 1975. There was a significant correlation between the incidence and the dose of radiation to the brain. The present findings strongly suggest that meningioma is one of the tumors induced by atomic bombing in Hiroshima.     

Radiological states around the Kraton-4 underground nuclear explosion site in Sakha

A radiological survey around the site of Kraton-4, an underground nuclear explosion (Yield of 20 kt, depth of 560 m, 1978) in Sakha was carried out in March 1998. Gamma survey and in-situ spectroscopy on the ground exhibited quite normal levels: a dose rate of 0.022 microSv/h and Cs-137 surface contamination of less than 1.1 kBq/m2 around the hypocenter. The results suggested no remarkable leakage of radioactivity from the epicenter to the ground surface at least not for non-rare gas elements as of 1998.     

Synthesis and biological activity of 1-N-[4-(substituted)amidino and guanidino-2-hydroxybutyryl]kanamycins A and B

The synthesis and biological properties of 1-N-[4-(substituted)amidino and guanidino-2-hydroxybutyryl]kanamycins A and B are described. Reaction of 3,3",6'-tri-N-tert-butoxycarbonyl-amikacin with an appropriate amidinating or guanidinating reagent and subsequent deblocking gave a series of amikacin derivatives having an amidino or guanidino group on the 4"'-position. The corresponding kanamycin B analogs were also prepared by a similar procedure. Among these derivatives, 1-N-(4-formamidino- and guanidino-2-hydroxybutyryl)kanamycins A (7a and 7k) and B (11 and 14) exhibited antibacterial activity similar to the corresponding 4-amino analogs. The nephrotoxic potential of selected compounds is also briefly discussed.     

Intraoperative radiation-therapy combined with hyperthermia for pancreatic-carcinoma

Seventeen patients with pancreatic carcinoma were treated with intraoperative radiation therapy (IORT) combined with hyperthermia. Their treatment results were compared with those of 56 patients treated with the IORT alone (control group). The pain relief rate and the local tumor control rate of the hyperthermia group were slightly better than the control group. The survival rate of all patients was 13.7% at one year, 1.4% at two years (median, 5.0 months). The survival of the hyperthermia group was marginally better than that of the control group. Only 29% of the patients of the hyperthermia group was successfully heated, and if hyperthermia were given successfully to all patients, their prognoses would have been possibly improved.     

Hypoglossal neurinoma--two case reports

Two patients presented with hypoglossal neurinoma extending both intra- and extracranially. A 63-year-old male presented with right trigeminal neuralgia and hypoglossal nerve paresis. The intracranial part of the tumor was removed totally via a suboccipital craniectomy. Over-coagulation of the venous collaterals, particularly the emissary veins, resulted in dural venous sinus thrombosis and cerebellar infarction. Unfortunately this patient died. A 48-year-old male presented with pareses of the VII, IX, X, XI, and XII cranial nerves and cerebellar sign. The tumor extended both extra- and intracranially, and was completely removed by opening the hypoglossal canal and the jugular foramen without over-coagulation of the venous collaterals. Preservation of the venous collaterals is very important for the prevention of postoperative venous complications.     

Suppressive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the high-affinity antibody response in C57BL/6 mice.

In the humoral immune response to an invasion of foreign antigens, B cells differentiate into low-affinity antibody-forming cells (AFCs) that mainly secrete IgM or, through germinal center (GC) formation, into high-affinity AFCs that secrete IgG-class antibodies with a higher affinity for the antigen. Previous studies have established the suppressive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on low-affinity antibody responses to antigens. However, whether and how TCDD affects the high-affinity antibody response to antigens has not yet been clarified. In this paper we investigate the effects of TCDD on GC formation, high-affinity AFC generation, and high-affinity antibody production in the primary humoral immune response. C57BL/6 mice were orally administered 0 or 20 microg/kg of TCDD and subsequently immunized with alum-precipitated ovalbumin (OVA) on day 0. Then the GC formation in the spleen and OVA-specific antibodies in the plasma, was evaluated until day 14 postimmunization. TCDD exposure reduced the production of OVA-specific IgG1 on days 10 and 14. GC formation in the spleen was also suppressed by TCDD exposure, and the suppression persisted from day 7 until day 14. In TCDD-administered mice, on day 7, cellular proliferation in the GCs was significantly suppressed, although apoptosis was not markedly affected. In order to measure high-affinity antibody and high-affinity AFCs, the mice were administered TCDD followed by immunization with alum-precipitated (4-hydroxy-3-nitrophenyl) acetyl linked to chicken gamma-globulin (NP-CG). The frequency of high-affinity NP-specific AFCs that bind to low-haptenated antigen was clearly shown to be reduced in the spleen on days 10 and 14. Furthermore, the high-affinity anti-NP IgG1 levels on days 10 and 14 postimmunization were significantly reduced by TCDD exposure. Taken together, the results of this paper demonstrate that TCDD exposure inhibits the generation of high-affinity AFCs and high-affinity antibody production during the primary humoral immune response and suggest that these alterations were caused by the suppression of antigen-responding B-cell proliferation induced by TCDD during GC formation.