[Ergocalciferol Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of ergocalciferol was examined for the preparation of "Ergocalciferol Reference Standard (Control 001)". Analytical data obtained were: melting point, 114.8 degrees C; UV and infrared spectra, the same as those of JP Ergocalciferol Reference Standard (Control 971); specific absorbance, E1ca1% = 471(265 nm); optical rotation, [alpha]D20 = +102.4 degrees; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.1%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Ergocalciferol Reference Standard (Control 001).

[Dexamethasone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material for dexamethasone sodium phosphate was examined for the preparation of the "Dexamethasone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 8.0; optical rotation, [alpha]D20 = +79.6 degrees; UV spectrum, lambda max of 242 nm and specific absorbance in water at 242 nm = 313.6; IR spectrum, same as that of the Dexamethasone Sodium Phosphate Reference Standard (Control 893); free phosphoric acid, 0.06%; free dexamethasone, 0.07%; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.2%; residual solvent, 4.3% (ethanol); water, 7.3%. Based on the above results, the raw material was authorized as the Dexamethasone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

[Alprostadil Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of Alprostadil was examined for the preparation of "Alprostadil Reference Standard (Control 001)". Analytical data obtained were: IR spectrum, same as that of the Alprostadil Reference Standard (Control 923); thin-layer chromatography, no impurities were detected until 20 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.2%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Alprostadil Reference Standard (Control 001).

[Hydrocortisone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of hydrocortisone sodium phosphate was examined for the preparation of the "Hydrocortisone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 8.3: optical rotation, [alpha]D20 = +126.2 degrees; UV spectrum, lambda max of 248 nm and specific absorbance in water at 248 nm = 338.6; IR spectrum, same as that of the Hydrocortisone Sodium Phosphate Reference Standard (Control 891); free phosphoric acid, 0.2%; free hydrocortisone, 0.01%; thin-layer chromatography, no impurity was detected until 200 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.2%; residual solvent, 0.0% (acetone) and 0.02% (ethanol); loss on drying, 1.5%. Based on the above results, the raw material was authorized as the Hydrocortisone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

[Cholecalciferol Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of cholecalciferol was examined for the preparation of "Cholecalciferol Reference Standard (Control 001)". Analytical data obtained were: melting point, 83.2 degrees C; UV and infrared spectra, the same as those of JP Cholecalciferol Reference Standard (Control 971), respectively; specific absorbance at 265 nm, E1ca1% = 478; optical rotation, [alpha]D20 = +108.6 degrees; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.05%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Cholecalciferol Reference Standard (Control 001).

[Beclometasone Dipropionate Reference Standard (Control 011) of National Institute of Health Sciences]

The raw material of beclometasone dipropionate was examined for the preparation of the "Beclometasone Dipropionate Reference Standard (Control 011)". The analytical data obtained were: melting point, 208.8 degrees C; optical rotation, [alpha]D20 = +91.7 degrees; IR spectrum, same as that of the Beclometasone Dipropionate Reference Standard (Control 865); thin-layer chromatography, one impurity was detected until 40 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.5%; loss on drying, 0.6%. Based on the above results, the raw material was authorized as the Beclometasone Dipropionate Reference Standard (Control 011) of the National Institute of Health Sciences.

[Berberine Hydrochloride Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of Berberine Hydrochloride was examined for preparation of the "Berberine Hydrochloride Reference Standard". The analytical data obtained were: UV spectrum: lambda max, 420, 345, 263 and 228 nm and specific absorbance (E1ca1%) in ethanol at each lambda max, 155, 724, 796 and 820, respectively; IR spectrum, specific absorptions at 2844, 1635, 1569, and 1506 cm-1; and the spectrum of raw material was consistent with that of Standard (Control 941). Also, thin-layer chromatography, an impurity was detected; high-performance liquid chromatography, several impurities were detected. The amount of each impurity was estimated at less than 0.1% and the total amount of impurities was less than 0.2%. Based on the above results, the candidate material was authorized as the Berberine Hydrochloride Reference Standard (Control 001) of the National Institute of Health Sciences.

Ganciclovir is effective for prophylaxis and treatment of human herpesvirus-6 in allogeneic stem cell transplantation

Human herpesvirus 6 (HHV-6) infection and disease are serious complications of allogeneic hematopoietic stem cell transplantation (allo-SCT). Ganciclovir (GCV) is effective against HHV-6 in vitro but the antiviral susceptibility of HHV-6 has not been well characterized in vivo. We retrospectively compared the HHV-6 reactivation rate in pediatric allo-SCT recipients with and without GCV prophylaxis. The HHV-6 reactivation rate at 3 weeks after allo-SCT in patients without prophylactic GCV administration was significantly higher than that in those receiving prophylactic GCV (11/28 vs 0/13, P < 0.01). Five of 36 patients without prophylactic GCV showed clinical manifestations including skin rash, interstitial pneumonitis, persistent thrombocytopenia, enterocolitis and thrombotic microangiopathy, respectively. HHV-6-associated symptoms were observed in one of the 13 patients receiving prophylactic GCV. This patient showed fever, diarrhea and graft rejection concomitantly with a sudden increase of HHV-6 DNA copy number. Patients who received GCV for treatment of HHV-6 infection showed an improvement in symptoms and/or decrease of HHV-6 copy number. Thus, GCV is effective for treating HHV-6 disease after allo-SCT in vivo.

Proliferative effects of eosinophil lysates on cultured human airway smooth muscle cells

BACKGROUND

The hypertrophy/hyperplasia of airway smooth muscle (ASM) cells is one of the characteristic features of bronchial asthma. This structural change leads to the thickening of airway walls resulting in the amplification of airway narrowing. However, the pathogenesis of this structural change has not yet been determined. Eosinophils, which play a pathogenic role in asthma, have been demonstrated to have proliferative effects on fibroblasts and vascular smooth muscle cells.

OBJECTIVE

We attempted to investigate the potential of eosinophils to induce the proliferation of ASM cells.

METHODS

We examined the effect of lysates of eosinophils purified from peripheral blood of healthy donors on cultured human ASM cell proliferation.

RESULTS

Eosinophil lysates significantly induced ASM cell proliferation in time- and dose-dependent manners, reaching a maximum on day 6 at 50% of eosinophil lysates (6.0 +/- 0.7 x 104 [mean +/- SD] /well, n = 5 vs. 4.5 +/- 1.1 x 104/well, n = 5; P < 0.05). This proliferative activity was heat-sensitive and recovered in the soluble fraction of the eosinophil lysates. Furthermore, the molecular weight of the mitogenic activity in the soluble fraction was identified as lower than 10 kDa. The inhibitory activity to ASM cell proliferation was also found in the insoluble fraction of the lysates.

CONCLUSION

These results indicate that circulating eosinophils store mitogenic activity for ASM cells, suggesting that eosinophils might contribute to the development of the hyperplasia of ASM cells in asthmatics through the release of the stored mitogenic activity upon stimulation at the site of inflammation.

[Bronchoscopic treatment for upper tracheal lesions with a laryngeal mask]

A laryngeal mask provides maintaining airway with a larger inner diameter of the tube. A little information is available about bronchoscopic treatment for upper tracheal lesions. Three patients undergoing bronchoscopic treatment for upper tracheal lesions with a laryngeal mask were reviewed. The patients include 3 women, having 2 thyroid cancers and 1 thyroid goiter. The aims of the procedure were hemostasis and reduction of the tumor with subsequent endotracheal stenting in 2 patients, and endotracheal stenting in one patient. The treatment was performed under general anesthesia using a laryngeal mask. All cases were successfully treated without operative and postoperative complications related to the use of the laryngeal mask placement. Use of a laryngeal mask may facilitate insertion and retrieval of a flexible bronchoscope and instruments with an excellent manipulation in therapeutic bronchoscopy for subglottic and upper tracheal lesions.

Cytomegalovirus hepatitis confirmed by in situ hybridization in 3 immunocompetent infants

We present 3 cases of immunocompetent infants with CMV infection who showed prolonged liver dysfunction. In all cases the CMV genome was detectable in hepatocytes using the in situ hybridization method. Combination therapy with ganciclovir (GCV) and hyperimmune gammaglobulin (HGG) was instituted in 2 cases and successfully suppressed the replication of CMV, with sustained improvement in liver function. In 1 of these cases, signals for CMV DNA were undetectable in the liver 12 months after termination of combination therapy. These results help to confirm the etiology of CMV for persistent hepatitis in immunocompetent infants using the in situ hybridization method and also show the efficacy of combination therapy with a virostatic agent, GCV, and an immune-modulating agent, HGG.

PACS linked to EPR

We developed a new PACS linked to Electronic Patient Record system (EPR). It was a hospital-wide PACS storing all the radiological examinations. The images and reports were linked on EPR. The concept of navigation servers and segment servers was introduced for prefetchig and quick displaying. After the start of operation, increasing retrieval indicated its effectiveness on practical work in spite of remaining delivery of radiographs.

[Tocopherol Acetate Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of tocopherol acetate was examined for the preparation of the "Tocopherol Acetate Reference Standard (Control 001)". Analytical data obtained were: IR spectrum, same as that of the Tocopherol Acetate Reference Standard (Control 974); specific absorbance, E/cm% (284 nm) = 43.7; thin-layer chromatography, no impurities were detected until 50 micrograms of the loaded raw material; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.6%; assay by HPLC, 101.7%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 001).

[Thiamine Hydrochloride Solution Reference Standard (Control 991) of National Institute of Health Sciences]

The raw material of thiamine hydrochloride solution was examined for preparation of the "Thiamine Hydrochloride Solution Reference Standard (Control 991)". The analytical data obtained were: assay by HPLC, 101.0%; spectrophotometric assay, 100.4%. Based on the above results, the raw material was authorized as the Thiamine Hydrochloride Solution Reference Standard (Control 991) of the National Institute of Health Sciences.

[Heparin Sodium Reference Standard (Control 991) of National Institute of Health Sciences]

The National Institute of Health Sciences Reference Standard for Heparin Sodium (Control 991) was prepared. The potency of heparin sodium for the candidate reference standard was assayed against "Heparin Sodium Reference Standard (Control 871)" by JP Method in collaboration with 4 laboratories, and estimated as 1,453 +/- 25 units per ampoule. The filling amounts of heparin sodium in ampoule was estimated as 7.46 +/- 0.15 mg per ampoule, and the precision of filling into ampoule was about 2.0% as C.V. Based on the above results, the candidate was defined as 1450 units per ampoule, and was authorized as the Heparin Sodium Reference Standard (Control 991) of the National Institute of Health Sciences.

[Tocopherol Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material of tocopherol was tested for the preparation of "Tocopherol Reference Standard (Control 991)". Analytical data obtained were: IR spectrum, same as the Tocopherol Reference Standard (Control 941); specific absorbance, E/cm% (292 nm) = 72.9; thin-layer chromatography, no impurities were detected until 50.0 micrograms; high-performance liquid chromatography (HPLC), trace amounts of five impurities were detected and the total amount was estimated to be less than 1.4%; assay by HPLC, 99.9%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 991).

[Prednisolone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences]

The raw material for prednisolone sodium phosphate was examined for the preparation of the "Prednisolone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 7.9; optical rotation, [alpha]D20 = +98.0 degrees; UV spectrum, lambda max of 248 nm and specific absorbance in ethanol at 248 nm = 306.7; IR spectrum, same as that of the Prednisolone Sodium Phosphate Reference Standard (Control 892); thin-layer chromatography, five impurities were detected at 200 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 3.7%; residual solvent, 0.0% (ethanol) and 0.0% (hexane); loss on drying, 2.7%. Based on the above results, the raw material was authorized as the Prednisolone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

Immature glandular features in squamous cell carcinoma of the uterine cervix as an independent indicator of resistance to radiotherapy

Abstract.

Okada S, Tsuda H, Ohmi K, Kasamatsu T, Yamada T, Tsunematsu R, Sumi M, Tokuuye K, Yoshikawa H, Hirohashi S. Immature glandular features in squamous cell carcinoma of the uterine cervix as an independent indicator of resistance to radiotherapy.

The aim of this study was to evaluate the significance of “immature glandular features” in cervical squamous cell carcinoma (SCC) as an indicator of tumor radioresistance. Pretreatment biopsied tissue specimens of cervical SCC from 100 patients who were uniformly treated with radiotherapy alone were classified into clinically radioresistant (cR) and radiosensitive (cS) groups. Seven histologic parameters comprising glassy cells, signet ring cells, squamous differentiation, recognizable gland, nuclear atypia, stromal response, and mitotic counts were examined. Glassy cells and signet ring cells were regarded as “immature glandular features”. The correlation of these seven parameters with tumor response to radiotherapy and patient prognosis was analyzed by univariate and multivariate analyses. As objective indicators of glandular differentiation, alcian-blue staining and immunostaining of cytokeratins 7 and 20 were also performed. It was revealed that immature glandular features, absence of squamous differentiation, and low nuclear atypia were significant indicators of radioresistance of the tumor and of poorer patient prognosis. Combining those histological parameters, the present SCC cases were classified into 26 pathologically radioresistant (pR) and 74 radiosensitive (pS) groups. In the pR group, 54% (14 of 26) were clinically radioresistant, whereas 20% (15 of 74) of the pS group were clinically radioresistant (P = 0.002). The overall prognosis of the pR group was much poorer than that of the pS group (P < 0.0001). This correlation also held true in cases of identical stage and age. We could not show objectively glandular differentiation of “immature glandular features”. Nonetheless, the identification of “immature glandular features” was effective in predicting the radiotherapy resistance of cervical SCC and poorer patient prognosis.

Mitochondrial coupling factor 6 is present on the surface of human vascular endothelial cells and is released by shear stress

BACKGROUND

We showed that mitochondrial coupling factor 6 (CF6), an endogenous inhibitor of prostacyclin synthesis, is present in the systemic circulation as a pressor substance in rats. We investigated the possibility of vascular endothelial cells as a source of circulating CF6.

METHODS AND RESULTS

We used 2 cultured endothelial cell lines, human umbilical vein endothelial cells (HUVECs) and ECV 304 cells (transformed HUVECs), for this study. Immunofluorescence microscopy of both ECV 304 and HUVECs confirmed the surface-associated immunoreactivity of anti-CF6 antibody on the plasma membrane. The concentration of CF6 in the medium increased gradually with time in both ECV 304 and HUVECs in static conditions. Exposure of ECV 304 and HUVECs to a fluid shear stress enhanced the release of CF6: In ECV 304, the concentration of CF6 in the medium (ng. well(-1). 6 hours(-1)) was 2.1+/-0.8 at baseline, 4.3+/-0.8 after shear at 15 dynes/cm(2), and 57.7+/-8.4 after shear at 25 dynes/cm(2). CF6 contents in the cell homogenate and mitochondria were both significantly increased after exposure of ECV 304 to 6-hour shear at 15 dynes/cm(2), whereas they were unchanged after shear stress at 25 dynes/cm(2). The ratio of CF6 to GAPDH mRNA was enhanced significantly, by 1.8+/-0.2-fold, after 6-hour shear stress at 25 dynes/cm(2). Flow cytometry analysis revealed that the surface-associated CF6 was significantly increased in a 3-hour static condition after the previous exposure of the cells to shear stress for 3 hours.

CONCLUSIONS

Vascular endothelial cells are a source of CF6, and shear stress regulates the release of the surface-associated CF6.

Escape from tolerance of organic nitrate by induction of cytochrome P450

The mechanism of organic nitrate tolerance is poorly defined. We studied the rat P450-catalyzed conversion of organic nitrate to nitric oxide (NO) by purified P450 isoforms relationship between P450 expression and nitrate tolerance following continuous infusion of organic nitrates in rats. The hypotensive effect of an nitroglycerin (NTG) bolus injection was abolished in rats that had been previously provided a continuous 48 h infusion of NTG. This effect was accompanied by a gradual but marked decrease in plasma and urinary nitrate levels following a peak at 18-24 h. Nitrate tolerance was reversible; the decline in the hypotensive effect and P450 levels observed after 2 d of continuous infusion was followed by restoration to control levels 2 d after cessation of the infusion. Similarly, the hypotensive action disappeared in P450-depleted, and -inhibited rats. At 48 h after infusion, NTG-induced NO generation of the vessels increased in acetone (a P450 inducer) -pretreated rats. The appearance and disappearance of P450 paralleled the conversion of organic nitrates to NO. Our observations indicate that nitrate tolerance is in large part the result of decreased P450 expression and activity. Interventions that maintain or increase P450 activity may be a strategy to provide relief from ischemic conditions in humans.

Pathology of radiation myelopathy

Radiation myelopathy is principally a white matter injury of the spinal cord induced by ionizing radiation after a certain latent period. It involves myelinated fibers and blood vessels, and the lateral funiculi is most preferentially affected. Several factors, such as radiation dose, fractionation or linear energy transfer, modify its occurrence and severity. Although glial cells and vascular endothelium are proposed to be the main targets, and to play a role in the pathogenesis of radiation myelopathy, experimental researches support that radiation-induced vascular damage resulting in vascular hyperpermeability and venous exudation is a basic process. Effect of ionizing radiation on each cellular component of the central nervous system, their contribution to radiation myelopathy, mechanisms of selective permeability and remaining problems are discussed.

Clinical relevance of in vitro chemoresistance in childhood acute myeloid leukemia

To determine the clinical relevance of in vitro drug chemoresistance in childhood acute myeloid leukemia, we used an MTT assay to test leukemic cells from 132 newly diagnosed children. Patients were diagnosed according to the French-American-British (FAB) classification as follows: M0 (n = 12), M1 (n = 16), M2 (n = 53), M4 (n = 17), M5 (n = 19) and M7 (n = 15). The results revealed that, compared to leukemic cells from complete-responders (n = 107), those from non-responders who failed induction therapy (n = 17) were 1.4 to 5.0 times more resistant in vitro to cytarabine (P = 0.005), melphalan (P = 0.003), etoposide (P = 0.011), L-asparaginase (P = 0.017), aclarubicin (P = 0.026) and dexamethasone (P = 0.039). For seven other drugs tested, the median lethal dose of 70% and leukemic cell survival of non-responders were higher than those of complete-responders, but the difference was not statistically significant. We sought correlations between FAB subtypes and in vitro drug resistance. Leukemias of the FAB M4 and M5 subtype were more sensitive to L-asparaginase (P = 0.01, P = 0.0036) than those of the FAB M2 subtype. FAB M5 leukemia was more sensitive to etoposide than were the FAB M2, M4 and M7 subtypes (P = 0.001, P = 0.034, P = 0.023, respectively). By contrast, FAB M5 leukemia was significantly more resistant to prednisolone and dexamethasone than were the FAB M0, M1, M2, M4 and M7 subtypes. We sought correlations between in vitro drug resistance and long-term clinical outcome, but found no associations in this case. These results suggest that in vitro resistance to cytarabine, melphalan, etoposide, L-asparaginase, aclarubicin and dexamethasone might represent factors that can predict response to the early course of therapy. Selecting an appropriate anti-cancer drug according to the FAB classification together with drug sensitivity testing may contribute to improved prognoses in childhood acute myeloid leukemia.

Mitotic index and ki-67 nuclear antigen labeling index as predictors of chemotherapy response in uterine cervical carcinoma

OBJECTIVE

The aim of this study was to determine if the mitotic index (MI) and the Ki-67 nuclear antigen labeling index (Ki67LI) obtained from biopsy specimens could be used as predictors of chemotherapy response in uterine cervical carcinomas.

METHODS

Six patients with squamous cell carcinoma who received neoadjuvant chemotherapy before radical surgery were entered into the study. The MI and the Ki67LI were evaluated using hematoxylin and eosin (H&E)-stained and immunostained slides before and after chemotherapy. Tumor size was measured three-dimensionally by magnetic resonance imaging. We compared the values of MI and Ki67LI with changes in tumor size.

RESULTS

The cases were classified according to the percentage reduction in tumor mass: one case showed a marked response (98%), four showed a moderate response (53-78%), and one showed a slight response (approximately 0%). In the case with a marked response, the MI values before chemotherapy and 3 and 7 days after chemotherapy were 15, 2, and 0, respectively. The corresponding Ki67LI values were 51, 16, and 0, respectively. In the moderate response cases, the corresponding MI values before and 3 and 7 days after chemotherapy were 3.9-13.6, 0.8-1.6, and 1.6-4.0, respectively. The Ki67LI was 21.8-44.2 before chemotherapy, with two cases increasing and two decreasing at 7 days after chemotherapy. In the case showing a slight response, the MI values before chemotherapy and 3 and 7 days after chemotherapy were 0.5, 0.8, and 1.0, respectively. The Ki67LI was 4.0 before chemotherapy and increased slightly to 6.0 at 7 days after chemotherapy.

CONCLUSIONS

In six cases examined, high MI and Ki67LI values before chemotherapy and a marked decrease in MI shortly after chemotherapy appeared to be predictors of good neoadjuvant chemotherapy response in uterine cervical carcinomas.

Metastasis of renal cell carcinoma to central nervous system hemangioblastoma in two patients with von Hippel-Lindau disease

Here we report tumor-to-tumor metastases identified in two patients with von Hippel-Lindau (VHL) disease. The first patient had bilateral renal carcinomas and multiple cerebellar hemangioblastomas, and the second patient had a renal carcinoma and multiple hemangioblastomas in the retina, cerebellum and spinal cord. A cerebellar lesion from the first patient and a spinal lesion from the second patient contained two distinct components. The inner part of these tumors consisted of a nested mass of polygonal clear cells that expressed cytokeratin and epithelial membrane antigen, while the outer part of the tumors showed proliferation of capillaries and intervening foamy stromal cells that were negative for cytokeratin and epithelial membrane antigen. The tumors were thus considered to be hemangioblastomas complicated by metastatic lesions of renal cell carcinoma of clear cell type. These cases indicate that tumor-to-tumor metastasis should be considered when hemangioblastoma contains a clear cell carcinoma component in the setting of VHL disease, and that immunohistochemical staining for cytokeratin and epithelial membrane antigen is useful for the diagnosis.

Analysis of gene expression of aldose reductase and sorbitol dehydrogenase in rat Schwann cells by competitive RT-PCR method using non-homologous DNA standards

Aldose reductase (AR) and sorbitol dehydrogenase (SDH) are the enzymes constituting the polyol pathway, an alternate route of glucose metabolism. A wealth of experimental data has indicated the involvement of the polyol pathway in the pathogenesis of diabetic complications. However, there has been surprisingly little research on the relative abundance of SDH to AR in the tissues affected in diabetes. We therefore developed a competitive RT-PCR system to simultaneously determine the mRNA levels of these two enzymes in small amounts of samples, and studied their expression in Schwann cells isolated from adult rat sciatic nerves. Although both AR and SDH mRNA were expressed in the Schwann cells, the levels of SDH cDNA were much lower than those of AR cDNA. The induction of AR mRNA expression in the Schwann cells under hyperosmotic conditions was similarly detected by Northern blot analysis and our competitive RT-PCR method. The RT-PCR system developed in this study may be a useful tool in ascertaining the relative contributions of AR and SDH to the metabolic derangements resulting from the acceleration of polyol pathway activity in the target organ of diabetic complications.

Distinctive multidrug sensitivity and outcome of acute erythroblastic and megakaryoblastic leukemia in children with Down syndrome

We assessed the in vitro chemosensitivity of acute erythroblastic and megakaryoblastic leukemia cells from children with Down syndrome (DS) compared to non-DS children. We conducted in vitro tests using the MTT assay of bone marrow samples from 12 children with DS and 16 children without DS. Patients were newly diagnosed based on the morphology and expression of platelet-specific antigens. Induction failure occurred more frequently in the non-DS group (n = 4) than in the DS group (n = 0, P = .053). Children with DS had a superior event-free survival (EFS) probability of 0.750 at 4 years, compared to an EFS probability of 0.375 for non-DS children (P = .049). Blast cells from DS patients were significantly more sensitive to daunorubicin, melphalan, mitoxantrone, 4-hydroperoxy-cyclophosphamide, vincristine, etoposide, bleomycin, and pirarubicin than those from non-DS patients. Four of the 16 non-DS patients were found to have acquired an extra chromosome 21 in their leukemia cells: blasts from these patients also tended to have greater chemosensitivity than those from patients without an extra chromosome 21. Blast cells from DS patients are markedly sensitive to various drugs. These results suggest that the fragility of blast cells derived from DS patients may be related to an increased susceptibility to apoptosis.

Isoform-dependent interaction of BRDG1 with Tec kinase

Tec is the prototype of an emerging family of protein-tyrosine kinases. Tec and Btk, another member of this family, together participate in the development of B-cell immune system. We previously identified one of the downstream messengers for human Tec kinase, BRDG1. BRDG1 is associated with Tec and becomes tyrosine-phosphorylated in B-cells by the engagement of B-cell antigen receptor (BCR). Here we show that overexpression of BRDG1 strongly augments BCR-mediated activation of cAMP-response element binding protein (CREB) but not that of c-Jun and the promoters of c-MYC and BCL-xL genes. Furthermore, we isolated the murine orthologue of BRDG1. Three isoforms of BRDG1 are generated by alternative splicing of the message. Two of them have a deletion of 33 amino acids in a Pleckstrin homology (PH) domain of BRDG1. Both the tyrosine-phosphorylation and CREB-activating ability of BRDG1 were isoform-dependent, suggesting a role of the PH domain of BRDG1. These data have identified a novel regulatory mechanism of CREB family of transcriptional factors.

Mutation of von Hippel-Lindau tumor suppressor gene in a sporadic endolymphatic sac tumor

Endolymphatic sac tumor (ELST) is a low-grade adenocarcinoma of the temporal bone that is presumed to originate from the endolymphatic system. Although ELSTs are extremely rare in the general population, a significant number of studies have documented the occurrence of ELST among patients with von Hippel-Lindau (VHL) disease. Because of the rarity of the tumor, however, few cases of ELST have been analyzed for mutations of the VHL tumor suppressor gene. In this study, we reported a Japanese male patient with sporadic ELST, along with a molecular genetic analysis of the VHL gene. The light microscopic and immunohistochemical features and clinical presentations were typical of ELST. Sequencing studies of the tumor DNA disclosed a G to T substitution of nucleotide 564, which resulted in an amino acid substitution (Trp to Cys). This is the first report of the VHL gene mutation in a sporadic Japanese case of ELST.

Effects of the acyl chain composition of phosphatidylcholines on the stability of freeze-dried small liposomes in the presence of maltose

The effects of the acyl chain composition of phosphatidylcholines (PCs) on the stability of small unilamellar vesicles during freeze-drying and rehydration in the presence of maltose were studied by monitoring the retention of a trapped marker, calcein, in the internal liposome compartment. In dipalmitoyl PC, beta-oleoyl-gamma-palmitoyl-PC and egg yolk PC liposomes, good or fair retentions (>50%) were observed in the presence of maltose, but maltose was ineffective in preserving retention in the dioleoyl PC (DOPC) liposomes (<10%). The extremely low retention in the DOPC liposome was ascribed to neither a formation of the inverted hexagonal phase of the liposomal membrane nor the fusion/aggregation of the liposomes in the drying-rehydration process. Differential scanning calorimetry measurements suggested that interactions of maltose with PC headgroups were essential to stabilizing the dry liposomes. These interactions were significant in the saturated or mixed chain liposomes but were markedly reduced in the DOPC liposomes.

Isolation of X and Y chromosome-specific DNA markers from a liverwort, Marchantia polymorpha, by representational difference analysis

The liverwort Marchantia polymorpha has X and Y chromosomes in the respective female and male haploids. Here we report the successful exploitation of representational difference analyses to isolate DNA markers for the sex chromosomes. Two female-specific and six male-specific DNA fragments were genetically confirmed to originate from the X and Y chromosomes, respectively.

Development and release characterization of hyaluronan-doxycycline gels based on metal coordination

A simple mixing with hyaluronan (HA), doxycycline (DC) and divalent metal cation in an aqueous solution enabled a thermoreversible water-soluble gel to form. For the cross-linking, two kinds of interactions were supposed. One was an electrostatic interaction between a positively charged group in DC and a negatively charged carboxyl function of HA, and the other was a chelation at the phenolic diketone moiety in DC. Since the gel was formed physically, the critical polymer concentration for gelation was present, and it was about 0.05% for HA with a molecular weight of 1.6x10(6). The hydrogel would be formed holding water in the HA entanglement network when DCs on HA chains made coordinate bonds through metal chelation. By changing the mixing ratio, two types of gels with different characteristics in drug release could be prepared. One was a gel with zero-order release prepared by mixing the same amount of HA and DC in equivalent. The other was a gel indicating Fickian diffusion-type release by mixing more DC than HA. Further, by controlling the absolute concentration of HA and DC, or the molecular weight of HA, some gels with desired release profiles could be prepared.

Practical asymmetric synthesis of a selective endothelin A receptor (ETA) antagonist

[structure: see text]. A practical, chromotography-free asymmetric synthesis was developed for the large scale preparation of an endothelin receptor antagonist 2. This synthesis includes a new efficient process for the preparation of 6-bromo-2,3-dihydrobenzofuran, a stereoselective conjugate addition of an aryllithium followed by stereospecific addition of the Grignard reagent of the top aryl bromide, and an aminophosphate-mediated sterospecific intramolecular enolate alkylation, which led to the formation of the five-membered ring bearing three contiguous asymmetric centers.

Bifurcation of osteoclasts and dendritic cells from common progenitors

Osteoclasts and dendritic cells are derived from monocyte/macrophage precursor cells; however, how their lineage commitment is regulated is unknown. This study investigated the differentiation pathways of osteoclasts and dendritic cells from common precursor cells at the single-cell level. Osteoclastogenesis induced by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-kappaB ligand (RANKL) or tumor necrosis factor-alpha (TNF-alpha) is completely inhibited by addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 at early stages of differentiation. GM-CSF-treated cells express both c-Fms and RANK and also low levels of CD11c and DEC205, which are detected on dendritic cells. Addition of GM-CSF also reduces expression of both c-Fos and Fra-1, which is an important event for inhibition of osteoclastogenesis. Overexpression of c-Fos by retroviral infection or induction in transgenic mice can rescue a failure in osteoclast differentiation even in the presence of GM-CSF. By contrast, differentiation into dendritic cells is inhibited by M-CSF, indicating that M-CSF and GM-CSF reciprocally regulate the differentiation of both lineages. Dendritic cell maturation is also inhibited when c-Fos is expressed at an early stage of differentiation. Taken together, these findings suggest that c-Fos is a key mediator of the lineage commitment between osteoclasts and dendritic cells. The lineage determination of osteoclast progenitors seen following GM-CSF treatment functions through the regulation of c-Fos expression.

Synthesis of a muscarinic receptor antagonist via a diastereoselective Michael reaction, selective deoxyfluorination and aromatic metal-halogen exchange reaction

An efficient synthesis of a structurally unique, novel M(3) antagonist 1 is described. Compound 1 is conveniently disconnected retrosynthetically at the amide bond to reveal the acid portion 2 and the amine fragment 3. The synthesis of key intermediate 2 is highlighted by a ZnCl(2)-MAEP complex 19 catalyzed diastereoselective Michael reaction of dioxolane 7 with 2-cyclopenten-1-one (5) to establish the contiguous quaternary-tertiary chiral centers and a subsequent geminal difluorination of ketone 17 using Deoxofluor in the presence of catalytic BF(3).OEt(2). The synthesis of the amine moiety 3 is highlighted by the discovery of a novel n-Bu(3)MgLi magnesium-halogen exchange reaction for selective functionalization of 2,6-dibromopyridine. This new and practical metalation protocol obviated cryogenic conditions and upon quenching with DMF gave 6-bromo-2-formylpyridine (26) in excellent yield. Further transformations afforded the amine fragment 3 via reductive amination with 35, Pd-catalyzed aromatic amination, and deprotection. Finally, the highly convergent synthesis of 1 was accomplished by coupling of the two fragments. This synthesis has been used to prepare multi-kilogram quantities of the bulk drug.

Effect of lactational exposure to 1,2,3,4- tetrachlorodibenzo-p-dioxin on cytochrome P-450 1A1 mRNA in the neonatal rat liver: quantitative analysis by the competitive RT-PCR method

BACKGROUND AND METHODS

The aim of this study was to assess the effect of lactational exposure to dioxins in neonates on the cytochrome P450 1A1 (CYP1A1) induction in the level of gene expression. Maternal rats were treated with a single dose of 50 or 100 micromol/kg 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD), a low potent congener of dioxins, on the first day post-partum (day 1). Induction of CYP1A1 mRNA expression was quantitatively analyzed by the competitive reverse transcription-polymerase chain reaction (RT-PCR) method.

RESULTS

The CYP1A1 mRNA was detectable at extremely low amounts in the liver of control neonates and mothers. The mRNA ratios of CYP1A1 to beta-actin in neonates were dose-dependently increased by the treatment of 1,2,3,4-TCDD of their mothers. Its peak occurred on day 6 and was sustained at the same level on day 10. Increases of the ratio with 100 micromol/kg 1,2,3,4-TCDD on day 2, 6 and 10 were 26-, 40- and 40-fold of the appropriate controls, respectively. These levels paralleled the activity of ethoxyresorufin-o-deethylase, representing CYP1A mediated monooxygenase. In the mother, the mRNA ratio was increased only to threefold of the control, 10 days after treatment.

CONCLUSION

Current RT-PCR procedure enabled to assess both constitutive and induced levels of CYP1A1 mRNA in the neonatal rat livers. Although the dose of 1,2,3,4-TCDD selected in this study was about 5000 times higher than the daily intake of dioxins in breast-fed infants, CYP1A1 mRNA was highly induced for a longer period of time in neonatal rats receiving 1,2,3,4-TCDD via lactation than the treated maternal rats.

Host and geographical factors influence the thermal niche of enteric bacteria isolated from native Australian mammals

The thermal profiles of 118 bacterial strains, representing six species of the family Enterobacteriaceae, isolated from a variety of native Australian mammals were determined under in vitro conditions. Each of the bacterial species had a unique thermal profile and differed in their minimum or maximum temperature for growth and in their response to changing temperatures. The taxonomic classification of the host from which the bacterial strains were isolated explained a significant amount of the variation in thermal profile among strains of a species. Host effects were detected at all taxonomic levels: order, family, genus, and species. The locality (State or Territory) or climate zone from which the strain was collected explained a significant amount of the variation in the thermal profile of Citrobacter freundii, Enterobacter cloacae and Klebsiella pneumoniae strains. Genetically similar strains, as determined by allozyme profiles, had similar thermal profiles for the bacterial species Hafnia alvei and Escherichia coli. The results of this study indicate that there are potentially many aspects of host biology that may determine the thermal profile of these bacteria.

[Thoracoscopic lung resection for a peripheral lung cancer by a single surgeon with a voice-controlled robot]

Thirty patients with a peripheral lung cancer underwent consecutive thoracoscopic lung resections with a voice-controlled robot between October 1998 and February 2001. The patients with a high risk such as cardio-pulmonary dysfunction or the patients aged 80 years or older were included. Patients with stage I cancer of the right lung in which lobectomy with lymph node dissection was anticipated were also included. Thirty thoracoscopic procedures were performed by a single surgeon using a voice-controlled robot. Thoracoscopic lung resection by a single surgeon with a voice-controlled robot was achieved in 27 patients. The postoperative follow-up period ranged from 3 months to 42 months. In all patients, thoracoscopic procedures without no need for a human assistant were achieved. There were no survival differences between the wedge resection group and lobectomy group, in the patients having adenocarcinoma and patients having squamous cell carcinoma, and elderly patients and young group patients. Complications related or unrelated to the maneuvers of a voice-controlled robot were not noted. Postoperative complications occurred in 4 patients (atelectasis 2, postoperative dementia 2). All of the events resolved within one week. Thoracoscopic lung resection such as wedge resection or lobectomy by a single surgeon with a voice-controlled robot may be feasible in selected patients with lung cancers. Its application must be confirmed by further studies.

Detection of numerical alterations of chromosome 1 in cytopathological specimens of breast tumors by chromogen in situ hybridization

To investigate the effectiveness of chromogen in situ hybridization (CISH) in the diagnosis of breast tumors, numerical alterations of chromosome 1 were examined by CISH and fluorescence in situ hybridization (FISH) methods, and the presence of der(16)t(1;16) was also examined by FISH in imprinted cytology specimens from resected tissues of 14 carcinomas and five non-malignant lesions. The modal signal counts of chromosome 1 were compared between the specimens processed by CISH and FISH for each case. Aneusomies of the long arm of chromosome 1 were detected in 10 (71%) carcinomas as the major clones by both methods. In addition, one atypical papilloma demonstrated tetrasomy of 1q12 as a major clone by CISH, but such a clone was at first overlooked by FISH. Four other benign lesions showed disomic 1q12 signals as a major clone by both CISH and FISH. As additional information from FISH, eight cancers showed structural or numerical alterations of chromosome 16, and four showed der(16)t(1;16). In total, 10 carcinomas showed chromosome 16 alterations, and all of these overlapped with the carcinomas with 1q12 aneusomies. The CISH method provided almost the same results as the FISH method, and both methods were considered applicable in supportive diagnosis of cytological specimens of breast tumors. In addition, the CISH method was superior in the detection of numerical alterations in carcinoma cells by referring to the morphology of cells and in the detection of significant clones which might be missed under dark-field microscopy.

Relationship between fear of falling and balancing ability during abrupt deceleration in aged women having similar habitual physical activities

The purpose of this study was to evaluate the influence of fear of falling on balancing ability during abrupt deceleration in aged women. The subjects were 20 women aged between 67 and 75 years. They were classified into two groups, one having a fear of falling (group FF, n = 10) and another without this fear (group NFF, n = 10). The two groups had similar daily physical activities. Changes in the centre of foot pressure (CFP) were measured during postural sway following horizontal deceleration of the force platform on which they were standing, and the response time and CFP displacement were evaluated. In addition, the electromyogram (EMG) onset in the tibialis anterior muscle and medial gastrocnemius muscle during abrupt deceleration, and its difference between the two muscles were measured. and the relative level of co-contraction of antagonistic muscles (the co-contraction index, CCI) in the lower extremity muscle group was calculated. The response time and CFP displacement immediately after abrupt deceleration were significantly higher in group FF than in NFF (P < 0.05). The EMG onset in the two muscles did not significantly differ between the two groups. The difference in EMG onset between the two muscles was significantly lower in group FF than in NFF (P < 0.05). The CCI was significantly higher in group FF than in NFF (P < 0.05). These results suggest that there were negative effects of a fear of falling on the balancing ability immediately after abrupt deceleration. This may be because a fear of falling increases the co-contraction of antagonist muscles in the lower extremity muscle group.

Mitochondrial coupling factor 6 as a potent endogenous vasoconstrictor

We demonstrated recently that coupling factor 6, an essential component of the energy-transducing stalk of mitochondrial ATP synthase, suppresses the synthesis of prostacyclin in vascular endothelial cells. Here, we tested the hypothesis that coupling factor 6 is present on the cell surface and is involved in the regulation of systemic circulation. This peptide is present on the surface of CRL-2222 vascular endothelial cells and is released by these cells into the medium. In vivo, the peptide circulates in the vascular system of the rat, and its gene expression and plasma concentration are higher in spontaneously hypertensive rats (SHRs) than in normotensive controls. Elevation of blood pressure with norepinephrine did not affect the plasma concentration of coupling factor 6. Intravenous injection of recombinant peptide increased blood pressure, apparently by suppressing prostacyclin synthesis, whereas a specific Ab to coupling factor 6 decreased systemic blood pressure concomitantly with an increase in plasma prostacyclin. Interestingly, the antibody's hypotensive effect could be abolished by treating with the cyclooxygenase inhibitor indomethacin. These findings indicate that mitochondrial coupling factor 6 functions as a potent endogenous vasoconstrictor in the fashion of a circulating hormone and may suggest a new mechanism for hypertension.

Multiple hepatic peribiliary cysts discovered incidentally at a medical examination

We report a living patient with multiple hepatic peribiliary cysts. It was discovered incidentally during an ultrasonographic screening at a medical examination. Peribiliary cysts are multiple retention cysts of peribiliary glands. Although many autopsy cases of peribiliary cysts have been reported, there are few clinical cases of it in living patients. A CT performed immediately after drip-infusion cholangiography (DIC) was most useful for diagnosis in various imaging tests we performed.

Treatment strategy for small hepatocellular carcinoma: comparison of long-term results after percutaneous ethanol injection therapy and surgical resection

This comparative study was conducted to clarify the efficacy of percutaneous ethanol injection (PEI) and surgical resection in the treatment of small hepatocellular carcinomas (HCC). Thirty-nine patients treated by PEI and 58 who underwent hepatic resection for small HCC (smaller than 3 cm and 3 or less in number) during the same period were enrolled. The surgery group included more patients with large and multiple bilobar nodules than the PEI group. The histological differentiation of the treated tumors became worse in the surgery patients than in those treated by PEI. On the other hand, the PEI group included more patients with a poor hepatic reserve, according to Child-Pugh grading, the ICG test, and the serum total bilirubin value. The 1-, 3-, and 5-year overall survival rates were almost identical between the 2 cohorts (100%, 82.1%, and 59.0%, respectively, in the PEI group; 96.6%, 84.4%, and 61.5%, respectively, in the surgery group) (P =.96). During the follow-up period, 33 of 39 (85%) and 41 of 58 (71%) patients developed tumor recurrence after PEI and surgery, respectively. Cumulative 1-, 3-, and 5-year tumor-free survival rates in the PEI group were 63.4%, 30.3%, and 9.7 %, whereas those in the surgery group were 75.5%, 44.7%, and 25.7%, respectively (P =.10). Our overall findings show that local therapy can achieve an actual 5-year survival rate of around 60% for patients with small HCC with the proper selection of treatment. A prospective randomized comparative trial is required to settle this longstanding issue.

[Awareness of the health and defecation tendencies among college students by location of domicile]

In order to compare the food habits and defecation tendencies by region, a questionnaire survey was conducted of 1722 college women (18-20 years of age) living in Sapporo (146), Sendai (183), Osaka (1214), and Kumamoto (179). (1) When questioned about food habits, less than 58.5% of the respondents in the four groups considered their food intake to be sufficient to maintain their health. In regard to knowledge about their food intake requirements, the positive response was the highest in Sendai (85.8%), followed by Kumamoto (58.2%) and Osaka (50.9%) with the lowest in Sapporo (41.1%) (p < 0.01, among the four groups). (2) The students in Sendai, Osaka, Kumamoto and Sapporo, 96.2%, 93.5%, 92.9% and 92.5%, respectively, considered that constipation could affect their health (p < 0.05, among four groups). The percentage of those with regular bowel movements every day, tended to decrease in the order of Osaka (22.2%), Sapporo (21.2%) and Sendai (20.8%), with the lowest in Kumamoto (12.3%). Bowel movements of less than three times a week were reported by 24.7% in Sapporo, 24.0% in Sendai, 23.2% in Osaka and 22.3% in Kumamoto (p < 0.01, among the four groups). (3) Of those who defecated every day, in terms of time of day, the percentage was high between waking and after breakfast, with the highest percentage in Kumamoto (72.8%) and the lowest in Sapporo (61.2%) (p < 0.05, among the four groups). For subjects that responded that they should have a bowel movement every day, the highest percentage was in Osaka (91.0%) and the lowest was in Sapporo (83.9%) (p < 0.05, among the four groups).

Role of advanced glycation end products in adynamic bone disease in patients with diabetic nephropathy

Adynamic bone disease and elevated serum levels of advanced glycation end products (AGEs) often are found in patients with renal failure caused by diabetic nephropathy. To clarify the role of AGEs in adynamic bone disease, we investigated the effect of these substances on cultured human osteoblasts and parathyroid cells. After 72 hours of incubation with AGEs-bovine serum albumin (BSA) (1,000 microgram/mL), there was significant inhibition of the synthesis of type I collagen and osteocalcin in response to stimulation with 10(-10) to 10(-8) M of 1,25-dihydroxycholecalciferol. In a human osteoblastic cell line (MG 63), AGEs-BSA did not affect human osteocalcin promoter activity. In human parathyroid cells, a receptor for AGEs was detected by reverse-transcriptase polymerase chain reaction. Incubation with AGEs-BSA for 48 hours significantly inhibited parathyroid hormone secretion in response to a low calcium concentration of 0.81 mM (P < 0.01). In HEK-293 cells, expressing calcium-sensing receptors, the same AGE concentration caused a significant potentiation of the extracellular Ca(2+) induced-intracellular calcium concentration after 24 and 48 hours of incubation (P < 0.05 and P < 0.01). These data suggest that AGEs are involved in the pathogenesis of adynamic bone disease by inhibiting osteoblastic activity and by inhibiting parathyroid hormone secretion in response to hypocalcemia.

Magnetic ordering in hexagonally bonded sheets with first-row elements

We report first-principles total-energy electronic-structure calculations in the density-functional theory performed for hexagonally bonded honeycomb sheets consisting of B, N, and C atoms. We find that the ground state of BNC sheets with particular stoichiometry is ferromagnetic. Detailed analyses of energy bands and spin densities unequivocally reveal the nature of the ferromagnetic ordering, leading to an argument that the BNC sheet is a manifestation of the flat-band ferromagnetism.

A new functional domain of Bcl6 family that recruits histone deacetylases

The proto-oncogene Bcl6 and its family gene, BAZF, encode a sequence-specific transcriptional repressor which contains the BTB/POZ domain in NH(2)-terminal region and zinc finger motifs in COOH-terminal region. The BTB/POZ domain and the middle portion of Bcl6 and BAZF are known to display transrepressor activity. Since we have identified the identical 17-amino acid (aa) sequence in the middle portion of Bcl6 and BAZF, the 17aa region may be another repressive domain of the middle portion. The reporter gene assay indicates that the 27aa sequence including the 17aa region recruits histone deacetylases to express transrepressor activity. Furthermore, overexpression of Bcl6 or Bcl6(POZ-) (Bcl6 deleted with the BTB/POZ domain) induced apoptosis in NIH3T3 cells, and the apoptosis was inhibited by the addition of histone deacetylase inhibitor in the culture. However, apoptosis was not induced in NIH3T3 cells by overexpression of Bcl6(POZ-) deleted with the 17aa region. These results indicate that the 17aa region in the middle portion of Bcl6 is a functional domain of transrepressor activity and is responsible for inducibility of apoptosis in NIH3T3 cells.

Polarized absorption spectra of single-walled 4 A carbon nanotubes aligned in channels of an AlPO(4)-5 single crystal

We report the polarized optical absorption spectra of single-walled 4 A carbon nanotubes arrayed in the channels of an AlPO (4)-5 single crystal. When the light electric field (E) is polarized parallel to the tube direction (c), the spectra display a sharp peak at 1.37 eV, with two broadbands at 2.1 and 3.1 eV. In the E perpendicular c configuration, the tube is nearly transparent in the measured energy region 0.5-4.1 eV. The optical dipole selection rules are discussed, and the absorption bands are assigned to the dipole transitions between the Van Hove singularities. The measured absorption spectra agreed well with the ab initio calculations of band structure based on the local density function approximation.

Oral exposure of dimethylarsinic acid, a main metabolite of inorganic arsenics, in mice leads to an increase in 8-Oxo-2'-deoxyguanosine level, specifically in the target organs for arsenic carcinogenesis

We have proposed that oral administration of dimethylarsinic acid (DMA), a metabolite of inorganic arsenics in mammals, rather than inorganic arsenics themselves, promotes lung and skin tumors by way of the metabolic production of free radicals such as dimethylarsenic peroxy radical [(CH(3))(2)AsOO*]. The purpose of the present study was to examine if dimethylarsenic has the ability to induce oxidative damage. 8-oxo-2'-deoxyguanosine (8-oxodG) was used as a biomarker of DNA oxidation. The oral administration of DMA enhanced significantly the amounts of 8-oxodG specifically in the target organs (skin, lung, liver, and urinary bladder) of arsenic carcinogenesis and also in urine, whereas arsenite did not. The dimethylarsenics thus may play an important role in arsenic carcinogenesis through the induction of oxidative damage, particularly of base oxidation.