UVA induces C-->T transitions at methyl-CpG-associated dipyrimidine sites in mouse skin epidermis more frequently than UVB

We studied the kinetics of mutation induction in skin epidermis and dermis of UVA-irradiated transgenic Muta mice and analyzed the sequence changes in 80 lacZ transgene mutants from the irradiated epidermis. The mutant frequency increased linearly in both the epidermis and dermis up to 240 kJ/m2 UVA, twice as efficiently in the epidermis as in the dermis, without provoking any inflammatory reactions in the exposed skin. The 83 mutations detected in the UVA-exposed epidermis were dominated by C-->T transitions (88%), found almost exclusively at dipyrimidine sites, and specified by four occurrences of CC-->TT tandem substitutions, suggesting that UV-specific photoproducts induced in DNA have a major role in the genotoxicity. No T-->G transversions, which have been considered as a UVA signature mutation, and few mutations suggesting the relevance of oxidative damage were recovered in the present study. An analysis of the bases adjacent to the mutated cytosines revealed that the 3'-cytosine of dipyrimidine sites is the preferred target of UVA-induced C-->T transition. Moreover, C-->T transitions were induced at dipyrimidine sites associated with CpG much more frequently by UVA than by UVB, forming hotspots at several of these sites. These results suggest that UVA contributes more to the formation of recurrent or hotspot mutations at methylated CpG sites in the mammalian genome than UVB, since methylation of the CpG motif is observed entirely in the lacZ transgenes and is known to enhance the formation of cyclobutane pyrimidine dimers by longer wavelength UV.     

Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor whose cytologic findings are infrequently reported. We describe scrape and fine-needle aspiration biopsy (FNAB) cytology findings of an extraskeletal osteosarcoma in the right shoulder of a 24-yr-old man. Initial computed tomography revealed multiple ossification foci within the lesion. After excision of the primary tumor, the tumor recurred 13 months later. Scrape smears of both the primary tumor and FNAB smears of the recurrent tumor revealed moderate cellularity, cell clusters, and individual cells, closely associated with dense, homogeneous, acellular matrix material. The cells had elongated, oval, or partially bizarre-shaped nuclei with a coarse chromatin pattern and prominent nucleoli. The scrape smears contained large fragments of matrix material consistent with osteoid.     

Eradication therapy of Helicobacter pylori for elderly patients in Japan

In Japan, an eradication therapy of Helicobacter pylori(H. pylori) for peptic ulcers of stomach and duodenum was approved by a health insurance since November 1, 2000. A method of an eradication therapy is as follows. Adult patients are received lansoprazole 30 mg, amoxicillin 750 mg, clarithromycin 200-400 mg at the same time twice daily for seven days. This therapy is based on a guideline of a Japanese association of Helicobacter Research. Many elderly patients have complications such as hypertension, cerebral vascular disturbance, heart failure and so on. Moreover, they often take a several medicine including NSAIDs(non-steroidal anti-inflammatory drugs). Therefore, you should pay attention especially to interaction of drugs when planning an eradication therapy of H. pylori for elderly patients.     

Effects of clarithromycin and amoxicillin on gastric emptying in rats

The effects of oral administration of clarithromycin (CLR), amoxicillin (AMX), and lansoprazole (LPZ) on gastric emptying in rats were investigated by a glass powder method and a phenol red method. By both test methods, no significant effects on gastric emptying were observed when CLR, AMX, or LPZ was administered alone or when the three drugs were administered concomitantly. The levels of gastrointestinal absorption of [(14)C]CLR and [(14)C]AMX were measured. Four hours after injection of [(14)C]CLR or [(14)C]AMX into the stomach and duodenum loops of rats, 86.63 and 1.27% of the original amount of [(14)C]CLR administered were recovered in the contents of the stomach and duodenum loops, respectively, and 80.01 and 55.88% of the original amount of [(14)C]AMX administered were recovered in the contents of the stomach and duodenum loops, respectively.     

Protection against lethal intra-abdominal sepsis by 1-(3-dimethylaminopropyl)-3-ethylurea

Sodium hyaluronate-carboxymethylcellulose (HA/CMC) formulations are gels that effectively reduce postoperative adhesions in both animals and humans, when placed in the peritoneal or pelvic cavities concomitant with surgical manipulation. However, it has been suggested that the use of these products may increase the risk of peritoneal infection after contamination with intestinal contents during surgery. Using the rat intra-abdominal sepsis model, we found that administration of HA/CMC gels before bacterial challenge did not increase mortality but did significantly protect rats against lethal infection. This effect was dose and time dependent. Protection was conferred not by the HA/CMC gels themselves but by 1-(3-dimethylaminopropyl)-3-ethylurea (EDU), a small molecule released from the gel complex under physiologic conditions. Our results suggest that the protective effect exhibited by EDU is related to down-regulation of T cell-dependent responses and suppression of the proinflammatory-cytokine cascade associated with mortality during the early phase of disease.     

Content and classification of clinical trials at a university hospital in Japan

"Standards on the Implementation of Clinical Trials on Drugs (New GCP)" is a Japanese government policy established in April 1998 with the aim of satisfying scientific and ethical requirements for industry-sponsored research, i.e., registration-directed clinical trials and clinical trials intended to support reexamination or reevaluation applications. Since then, efforts for more effective implementation of clinical trials have been promoted, including establishment of a system to invite more active participation of subjects in clinical trials and improvement of a network of medical institutions conducting clinical trials. These efforts should help to reactivate clinical trials in Japan, which reportedly have become stagnant. Although the New GCP addresses the quality of industry-sponsored clinical trials, investigators also construct study protocols without industry involvement. We reviewed clinical trials submitted by investigators at Gunma University Hospital to institutional review boards (IRBs) from June 1999 to February 2002. Ten clinical research coordinators contributed to the present survey. A total of 151 investigator-initiated clinical trials reviewed included a wide variety of content; and investigators from many institutions and organizations conducted trials. Most of the ethical guidelines for approving proposed trials represented the provisions of the Declaration of Helsinki. However, additional guidelines prepared by the Japanese Ministry of Health, Labour and Welfare were also helpful. Development of a support system for clinical trails requires the contribution of clinical research coordinators. Flexible management and careful attention to both the protocol and its execution by the investigators were also important for promoting clinical trials on the basis of meticulous patient care.     

Limitin, an interferon-like cytokine, transduces inhibitory signals on B-cell growth through activation of Tyk2, but not Stat1, followed by induction and nuclear translocation of Daxx

OBJECTIVE: Limitin, an interferon-like cytokine, suppresses B lymphopoiesis through ligation of the interferon-alpha/beta (IFN-alpha/beta) receptor. The aim of this study was to examine the intracellular signal transduction pathways activated by limitin. MATERIALS AND METHODS: The effects of limitin on cell growth, the activation of Jak kinase and Stat proteins, and the induction of interferon regulatory factor-1 (IRF-1) and Daxx were examined using the mouse pre-B-cell line 18.81, wild-type, and Tyk2-deficient mouse bone marrow cells. In addition, the change of localization of the Daxx protein after limitin treatment in wild-type and Tyk2-deficient mice was examined. RESULTS: Limitin phosphorylates Tyk2, Jak1, Stat1, and Stat2 and rapidly induces IRF-1 mRNA production. Phosphorylation of Stat1 by limitin is partially dependent on Tyk2. Suppression of B-cell growth by limitin, however, is severely impaired in the absence of Tyk2, whereas it is unaffected by the absence of Stat1. Limitin also induces the expression and nuclear translocation of Daxx, which is essential for IFN-alpha-induced inhibition of B-lymphocyte development. The absence of Tyk2 abrogates this induction of Daxx expression and nuclear translocation. CONCLUSIONS: Limitin suppresses B-cell growth through activation of Tyk2, resulting in the up-regulation and nuclear translocation of Daxx. This limitin-mediated signaling pathway does not require Stat1.     

Potential limitations in using minor histocompatibility antigen-specific cytotoxic T cells for targeting solid tumor cells

We have shown previously that KIAA0223, a gene encoding a minor histocompatibility antigen, HA-1, whose expression was believed to be restricted to the hematopoietic cells, is aberrantly expressed in some solid tumor cell lines. However, its significance in tumor immunity needs to be determined. Cytotoxic activity of HA-1(H)-specific cytotoxic T lymphocytes (CTLs) was assessed against solid tumor cell lines expressing KIAA0223 using (51)Cr release assays. Five of seven cell lines were lysed when HLA-A*0201 was adequately expressed. One of the two CTL-resistant cell lines became susceptible after treatment with IFN-gamma and TNF-alpha, while the other was lysed only after pulsing with HA-1(H) peptide. In most cell lines tested, HA-1(H) peptide was properly generated and presented for recognition by the CTL. However, impaired antigen processing and presentation observed in this study may result in escape from CTL recognition in vivo, as well as in vitro, as observed in this study.