Benzene is a human leukemogen and the metabolites are thought to be deeply involved in benzene leukemogenesis. In a previous study we reported the molecular analysis of p-benzoquinone (p-BQ) mutagenesis by using a supF shuttle vector plasmid and here we report the mutagenesis of the other metabolites, hydroquinone (HQ) and trans, trans-muconaldehyde (MUC). HQ is a precursor of p-BQ and MUC is produced by a ring-opening metabolic pathway. We found that the HQ redox cycle produced an oxidative lesion in plasmid DNA and significant differences among the mutagenic potentials of MUC, HQ and p-BQ. HQ has stronger mutagenicity than the others. It is about 20 and 600 times stronger than p-BQ and MUC, respectively. Furthermore, we found notable differences in each mutational feature. The MUC mutational type was characterized by a high frequency of tandem base substitutions that could be due to crosslinks produced by its aldehyde moieties, while HQ was characterized by frequent deletion. This HQ feature is the same as in vivo benezene mutagenesis of Big Blue mice reported by Provost et al. in 1996 and is also quite similar to a hydrogen peroxide mutational feature. Therefore, we presume that HQ and reactive oxygen species may play an important role in benzene carcinogenesis. 相似文献
A case of recurrent soft part sarcoma with focal areas showing epithelial differentiation in the right thigh in a 78-year-old woman is reported. The primary tumor consisted of myxoid areas and solid areas, in which relatively uniform epithelioid tumor cells were arranged in sheets, whereas pleomor-phism and a storiform pattern appeared in the recurrent tumors. Thus this tumor was suspected to be a malignant fibrous histiocytoma. However, further studies showed unexpected ultrastructural and immunohistochemical features. Cytokeratin immu-noreactivity and tonofilamentlike structures probably indicated epithelial differentiation of some tumor cells. From the clinical and histological findings, this tumor should be identified as a malignant fibrous histiocytoma with phenotypic expressions of epithelial cell. 相似文献
Summary: Energy‐filtering transmission electron microscopy (EFTEM) was employed for the analysis of polymer‐polymer interfaces. To attain imaging and spectral analyses with a spatial resolution of 10 nm, problems arising in the EFTEM analysis for polymer specimens were investigated. Interfaces in poly(methyl methacrylate)/polystyrene‐co‐polyacrylonitrile random copolymer (PMMA/SAN) bilayer films annealed at different temperatures were analyzed by means of elemental mapping and Image‐EELS on EFTEM and the effect of the annealing temperature on the interfacial structures was also investigated.
ABSTRACT: Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM. 相似文献
After I graduated from Nagoya University School of Medicine in 1979, I was trained as a resident and physician at Nagoya Ekisaikai Hospital for 4 years. Then, I was trained as an anatomic pathologist by individual discussions of diagnostic problems using a multi-headed microscope at the Division of Pathology, Clinical Laboratory, Nagoya University Hospital for 5 years. When I entered the field of clinical pathology, there were few experienced clinical pathologists in Nagoya, so I needed the support of medical technologists for training in this field. Recently, I have been advancing my career as a clinical pathologist by offering consultations to physicians and holding a reversed clinico-pathological conference for medical technologists. It took me about 20 years to become a fully qualified pathologist. I think that a systematic curriculum for postgraduate training in anatomic pathology/clinical pathology should be indispensable to pathologists. 相似文献
In order to obtain a gelatin hydrogel crosslinked by a reagent-free method, gamma-ray and electron beam radiation was applied to porcine, bovine and fish gelatin gels and the products were characterized by measuring the gel fraction, the swelling ratio and the enzymatic degradability. On increasing the radiation dose, the gel fraction increased and both the swelling ratio and the enzymatic degradability decreased. The transition temperature from gel to sol of the hydrogel containing more than 5% mammal gelatins increased up to more than 90 degrees C when gamma-ray or electron beam were irradiated by more than 10 kGy. The results show that the degree of crosslinking of irradiated gelatin hydrogels increases with increasing irradiation dose and with decreasing concentration. It is suggested that the radiation crosslinking occurs around the physical crosslinking point or multiple helix structure of gelatin gel. 相似文献
On February 13, 2002, a public health center in Hiroshima Prefecture, Japan, was notified that many individuals living at the Japan Maritime Self-Defence Force base had symptoms resembling those of food poisoning. Self-administered questionnaires requesting information regarding meal consumption and symptoms were distributed to all 281 members at the base. A case of the illness was defined as a member who had had watery or mucousy stool, or loose stool with abdominal cramps, more than twice a day after consuming dinner on February 12. Control of the illness was defined as a member with no symptoms. The dinner on February 12 was significantly associated with the illness (Mantel-Haenszel odds ratio: 3.59, 95% confidence interval: 1.06-12.20). A case-control study showed that, among the food supplied at dinner on February 12, the braised chop suey was significantly associated with the illness (odds ratio: 12.30, 95% confidence interval: 1.90-521.00). The braised chop suey had been stored in a chafing dish. An environmental investigation indicated that Clostridium perfringens (C. perfringens) in the chafing dish proliferated under an inappropriate heat-retention temperature, and the contaminated braised chop suey could have caused the food poisoning. This study demonstrated that the recommended heat-retention temperature (over 65 degrees C) should be confirmed thoroughly. 相似文献
We investigated the relationship between somatosensory event-related potentials (ERP) and the variation of reaction time (RT).
For this purpose, we recorded the ERPs (N250 and P300) in fast- and slow-reaction trials during a somatosensory discrimination
task. Strong, standard, and weak target electrical stimuli were randomly delivered to the left median nerve at the wrist with
a random interstimulus interval (900–1,100 ms). All the subjects were instructed to respond by pressing a button with their
right thumb as fast as possible whenever a target stimulus was presented. We divided all the trials into fast- and slow-RT
trials and averaged the data. N250 latency tended to be delayed when the RT was slow, but not significantly. P300 latency
was delayed significantly when the RT was slow, but to a much lesser extent than the RT delay, so we concluded that the change
of RT was not fully determined by the processes reflected by the somatosensory N250 or P300. Furthermore, the larger and earlier
P300 in the fast-RT trials implied that when larger amounts of attentional resources were allocated to a given task, the speed
of stimulus evaluation somewhat increased and RT was shortened to a great extent. N250 amplitude did not significantly vary
in the two RT clusters. In conclusion, the somatosensory N250 reflects active target detection, which is relatively independent
of the modulation of the response speed, whereas the somatosensory P300 could change without manipulation of either the stimulus
or the response processing demand.
Electronic Publication 相似文献
The post-operative pain state results from a barrage of primary afferent inputs exposed to products of tissue damage such as bradykinin and prostaglandins and the central sensitization by the continuing inputs. This provides the rationale for preemptive analgesia, whereby the blockade of primary afferent inputs prior to injury may result in a reduction of post-operative pain. 2-(10,11-dihydro-10-oxo-dibenzo[b,f]thiepin-2-yl) propionic acid (zaltoprofen) is a unique compound that inhibits cyclooxygenase (COX) and exhibits anti-bradykinin activity. The present study evaluated the preemptive analgesic effect of zaltoprofen in a post-operative pain model produced by plantar incision. When orally, but no intrathecally, administered 30 min prior to incision, zaltoprofen significantly increased the withdrawal threshold 2 h and 1-3 days after incision at 10 mg/kg. While the bradykinin B1 antagonist des-Arg10-HOE-140, the selective COX-1 inhibitor SC-560, and the selective COX-2 inhibitor celecoxib did not affect post-operative pain, the B2 antagonist HOE-140 dose-dependently relieved the post-operative pain at 2-200 microg/kg with a time course similar to that of zaltoprofen. The B2 receptor mRNA was expressed in the hindpaw and the expression did not change before and 24 h after surgery. These results suggest that zaltoprofen produces the preemptive analgesic effect peripherally by blocking the B2 pathway. 相似文献