A mechanistic study of reactions of stable disilenes with haloalkanes.

Mechanisms of the reactions of three tetrakis(trialkylsilyl)disilenes and a tetraaryldisilene with various haloalkanes such as carbon tetrachloride, chloroform, dichloromethane, which gave the corresponding 1-alkyl-2-chlorodisilanes and/or 1,2-dichlorodisilanes, were investigated in detail. As evidenced by an ESR observation of an intermediate radical, these reactions were quite unusual, forming neutral radical pairs from two closed shell molecules at the first step; no similar reactions have been observed between alkenes and haloalkanes. Low oxidation potentials of these disilenes, large negative activation entropies, and solvent effects for the rates are in good accord with the direct halogen abstraction of disilenes from haloalkanes instead of single-electron transfer at the rate-determining first step. The structure--reactivity relationship of the reactions and the Hammond postulate suggest that the transition state structures for the first step are similar to those for the halogen abstraction by silyl radicals, but more product-like.

Development of a new triphase catalyst and its application to the epoxidation of allylic alcohols.

[see reaction]. A new triphase catalyst has been developed. When an aqueous solution of H3PW12O40 (1) was added to a solution of the amphiphilic chain copolymer 2, a new self-assembled and macroporous complex 3 was formed. This complex was effective as a catalyst in the epoxidation of allylic alcohols. Even in the use of 2.7 x 10(-5) mole equiv of the catalyst, the epoxidation with aqueous H2O2 proceeded without organic solvents to give the corresponding epoxy alcohols in high yields.

A new pathway in the reaction of disilene with carbonyl compounds: an 'ene' reaction instead of cycloaddition.

The 3H-disilagermirene, (tBu2MeSi)4GeSi2, reacts with alpha-hydrogen containing carbonyl compounds (acetophenone, butane-2,3-dione) by an 'ene'-reaction pathway followed by isomerization or insertion reactions, representing a new mode in the reaction of disilenes with carbonyl compounds.

Case report. Onychomycosis due to Chaetomium globosum successfully treated with itraconazole.

We have experienced a case of toenail infection caused by Chaetomium globosum which we treated with itraconazole 100 mg day-1 for 6 months, after which time the nail lesions were almost cured. Our case is the first reported case of onychomycosis caused by Ch. globosum in Japan, and the seventh in the world.

Synthesis, Characterization, and Crystal Structure of Cyclotrisilene: A Three-Membered Ring Compound with a Si-Si Double Bond.

Red-orange crystals of cyclotrisilene 3 were obtained by the reaction of the dibromotrisilane 1 and the tribromodisilane 2 with sodium in toluene [Eq. (1)]. The X-ray crystal structure of 3 shows that the three-membered ring is almost an isosceles triangle and has a twisted Si-Si double bond with a length of 2.138(2) Å.

A Free Cyclotrigermenium Cation with a 2pi-Electron System

The reaction of tetrakis(tri-tert-butylsilyl)cyclotrigermene with trityl tetraphenylborate in benzene produces tris(tri-tert-butylsilyl)cyclotrigermenium tetraphenylborate [(tert-Bu3SiGe)3+BPh4-], which can be isolated as a yellow solid that is stable in the absence of air. The crystal structure of the cyclotrigermenium ion reveals a free germyl cation with a 2pi-electron system. The three germanium atoms form an equilateral triangle similar to the carbon analog, the cyclopropenium ion.

Observation of positional nystagmus with infrared CCD camera.

Using infrared CCD camera and electronystagmography we analyzed positional nystagmus in 33 patients with peripheral positional vertigo. Patients were classified into three types; (a) lateral type: nystagmus occurs in lateral position, (b) sagittal type: nystagmus occurs in head-hanging position (so-called benign paroxysmal positional vertigo, BPPV), and (c) mixed type. Nystagmus in the lateral type was horizontal and that in the sagittal type was rotatory. In all types, the vertigo and nystagmus began with a few seconds' latency after head tilt and briefly increased to a maximum, and then gradually decreased. The duration of horizontal nystagmus in the lateral and mixed type was significantly longer than that of rotatory nystagmus in the sagittal type mixed type. The mean value of the former was 90.6 s and that of the latter 18.1 s. We suggest that the velocity storage mechanism of the horizontal vestibulo-ocular reflex (VOR) is considerably different from that in the vertical VOR.

Current research on the major nematode problems in Japan.

AMONG IMPORTANT NEMATODE SPECIES OCCURRING IN JAPAN, CURRENT RESEARCH ACHIEVEMENTS WITH THE FOLLOWING FOUR NEMATODES ARE REVIEWED: 1) Soybean cyst nematode (SCN), Heterodera glycines - breeding for resistance, race determination, association with Cephalosporium gregatum in azuki bean disease, and isolation of hatching stimulant. 2) Potato-cyst nematode (PCN), Globodera rostochiensis - pathotype determination (Ro 1), breeding for resistance, and control recommendations. 3) Pinewood nematode (PWN), Bursaphelenchus xylophilus - primary pathogen in pine wilt disease, life cycle exhibiting a typical symbiosis with Japanese pine sawyer, Monochamus alternatus, and project for control. 4) Rice root nematodes (RRN), Hirschmanniella imamuri and H. oryzae - distribution of species, population levels in roots, and role of these nematodes in rice culture.

Allergic bronchopulmonary aspergillosis due to Aspergillus oryzae.

A 19-year-old female student with allergic bronchopulmonary aspergillosis (ABPA) due to Aspergillus oryzae is reported. This organism was used for fermentation starter to make soybean paste in her father's workshop adjacent to the home where she lived. ABPA might be considered an occupational disease in certain situations.

[Study on the toxicity of SF-1008C (II): Subacute toxicity study in rats].

The toxicity of an elemental diet (SF-1008C) for hepatic failure and recovery after administration were investigated in Sprague-Dawley rats. The rats were orally administered the drug in doses of 10, 20 and 30 g/kg/day for five weeks, after which, recovery was studied for five weeks. The results were summarized as below: In the 30 g/kg/day group, decreases in food and water consumption were observed, while the body weight gain and the rate of body weight gain were high compared to the treated control group. In addition, urinary pH and serum total protein were lower, and serum glucose and calcium levels were higher than in the treated control group, but these results were not considered to be due to the drug's toxicity. In the 20 and 10 g/kg/day groups, a slight decrease in food consumption was observed, though the rate of body weight gain was higher than in the treated control group. Slight decreases in urinary pH and serum total protein were observed, but were not considered to be due to the toxic effect of the drug. From the above results, it was concluded that the maximal non-effect dose of SF-1008C in oral administration was 30 g/kg/day, which was the maximally applicable dose in rats.

[Study on toxicity of halopredone acetate. (I) Acute toxicity study in mice and rats].

Since halopredone acetate (THS-201), a synthetic corticosteroid, is expected to be used clinically for intra-articular injections because of its long-lasting activity in the synovial bursa, its acute toxicity was compared with that of triamsinolone acetonide (TA) and methylprednisolone acetate (MPA). The test animals were Jcl: ICR mice and Jcl: Wistar rats, and drugs were administered orally, intraperitoneally and subcutaneously. The LD50 values of THS-201 both in mice and rats were estimated more than 5000 mg/kg at each route, and these are for above larger than those of TA or MPA. Moreover, in oral and subcutaneous administration of THS-201, no severe toxic signs were observed either in mice or in rats. In intraperitoneal injection, a few of mice and rats died after showing several clinical signs and suppression of body weight gain, and their autopsy revealed atrophy of thymus, spleen and adrenal, induction of infection and hemorrhage in digestive tract. On the other hand, the mice and rats administered TA or MPA revealed the severe toxic signs such as loss of hair gloss, marked emaciation, decrease in spontaneous movement, anemia, bloated face, decrease or suppression of body weight gain, atrophy of thymus, spleen and adrenal, severe induction of infection and lesions in digestive tracts. Accordingly, it is concluded that the acute toxicity of THS-201 in mice and rats was lower than that of TA or MPA.

[Study on toxicity of halopredone acetate. (II). Subacute toxicity study in rats].

Halopredone acetate (THS-201), a synthetic corticosteroid, is expected to be used clinically for intra-articular injection because of its long-lasting activity in the synovial bursa. Subacute toxicity study was carried out on THS-201 by using Jcl: Wistar rats. THS-201 was subcutaneously administered to the rat in doses of 0.1, 0.5, 2.5 and 12.5 mg/kg/day, with the periods for administration and recovery being 3 and 2 months, respectively. Methylprednisolone acetate (MPA) was used for the positive control in dose of 0.5 mg/kg/day. In the group of THS-201 12.5 mg/kg, the below findings were observed: thinning of lumbar hair, swelling of injection site, suppression in body weight gain and decrease of food consumption. The lesions to lymphatic system were indicated by the examinations of peripheral blood, autopsy and histopathology. Slight changes in erythrocytic and biochemical values were seen, and foreign body granuloma was observed in injected subcutis. These findings, exception for lesion of injection site, were almost recovered after the 2 month-recovery period. In the group of THS-201 2.5 mg/kg, some of the changes were noted slightly. In the groups of THS-201 0.5 and 0.1 mg/kg, any toxic changes attributable to THS-201 were not observed. On the other hand, in the group of MPA 0.5 mg/kg, similar findings noted in THS-201 12.5 mg/kg group were observed, but these changes were recovered almost completely at the end of the 2 month-recovery period. It was concluded that the non-toxic dose and the defined toxic dose of THS-201 in this study were 0.5 and 2.5 mg/kg/day, respectively.

[Study on toxicity of halopredone acetate. (III). Chronic toxicity study in rats].

Chronic toxicity study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. THS-201 was subcutaneously administered to the rat in doses of 0.02, 0.1, 0.5 and 2.5 mg/kg/day, with the periods for administration and recovery being 12 and 2 months, respectively. In the group of THS-201 2.5 mg/kg, the below findings were observed: thinning of lumbar hair, suppression in body weight gain, decrease of food consumption in both sexes and decrease of water consumption in male. The lesions to lymphatic system were indicated by the examinations of hemogram, organ weight and histopathology. A few changes in urinary and biochemical values were seen, and foreign body granuloma was observed in the injected subcutis. After 2 month-recovery period, above-mentioned findings almost disappeared. In the group of THS-201 0.5 mg/kg, some of the changes were noted slightly and disappeared after the recovery period. In the groups of THS-201 0.1 and 0.02 mg/kg, any toxic changes attributable to THS-201 were not observed. It was concluded that the non-toxic dose and the defined toxic dose of THS-201 in this study were 0.1 and 0.5 mg/kg/day, respectively.