Mutagenicity of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid treated with nitrite in the presence of alcohols

The mutagenicity of a product produced from 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), which is a component in soy sauce, after treatment with 50 mM nitrite at pH 3, 37 degrees C, for 60 min in the presence of 7.5% ethanol was much higher than that in the absence of ethanol during the nitrite treatment. The enhancement of the mutagenicity of nitrite-treated MTCCA by ethanol required simultaneous treatment of MTCCA with nitrite and ethanol. The mutagenicity of MTCCA treated with nitrite in the presence and absence of ethanol was detected in the same fractions on HPLC and was highest for Salmonella typhimurium strain YG1029 possessing elevated O-acetyltransferase activity among the several Salmonella test strains, suggesting that the same mutagen belonging to aromatic compounds was produced both in the presence and absence of ethanol. Methanol, n-propanol and isopropanol as well as ethanol were also observed to have an augmenting effect. However, the sugars glucose and sucrose had no effect. When MTCCA was treated with nitrite in the presence of commercial alcoholic beverages equivalent to 1.25-10% ethanol, Japanese 'sake' and 'shochu' were demonstrated to have a highly augmenting effect and beer, wine, whisky and brandy to have a mildly augmenting effect.

ErbB-2 expression is correlated with poor prognosis for patients with osteosarcoma

BACKGROUND

It has been reported that the c-erbB-2 protooncogene is frequently amplified and overexpressed in many types of cancers, except sarcomas and hematological malignancies.

METHODS

Expression of ErbB-2 in the tumors of 26 patients with conventional osteosarcoma was evaluated by immunoblotting. DNA from osteosarcoma tissues that expressed ErbB-2 were analyzed by Southern blot hybridization to examine gross rearrangement of the gene. The DNA was also surveyed for the presence of genetic mutation in the transmembrane domain of ErbB-2 by polymerase chain reaction-single-stranded DNA conformation polymorphism analysis. In addition, possible correlation of ErbB-2 expression with gender, age, histopathologic subtype, and response to chemotherapy was analyzed. Survival analysis was performed by the Kaplan-Meier test using the approximate chi-square statistic for the log-rank test.

RESULTS

The ErbB-2 protein was detected in 11 of 26 osteosarcoma tissues (42%) by immunoblot analysis. Expression of ErbB-2 was confirmed by immunohistochemical studies using specific anti-ErbB-2 monoclonal antibody. However, neither amplification of the c-erbB-2 gene nor evidence of significant genetic mutation was found in these osteosarcomas. Expression of ErbB-2 examined by immunoblotting was most strongly correlated with early pulmonary metastases (P < 0.05). Among the entire group of 26 patients in this study, Kaplan-Meier life table survival of the patients with apparent ErbB-2 expression was significantly worse than that of the patients with little ErbB-2 expression (P < 0.01).

CONCLUSIONS

In 42% of the osteosarcomas, the tumor cells expressed ErbB-2. Expression of ErbB-2 was strongly correlated with early pulmonary metastasis and poor survival rate for the patient. These data suggest that ErbB-2 plays a significant role in aggressive tumor growth and in the promotion of metastatic potential in osteosarcomas. ErbB-2 in the osteosarcoma tissues would be a useful prognostic marker for patients.

Immunohistochemical localisation of aromatase and its correlation with progesterone receptors in ovarian epithelial tumours

Aromatase cytochrome P-450 was immunohistochemically localised exclusively in the cytoplasm of neoplastic cells of benign and malignant nonfunctional ovarian tumours, whilst (progesterone receptors (PR) and estrogen receptors) (ER) were localised exclusively inn the nuclei of neoplastic cells. Aromatase activity and PR were detected in 68% (17/25) and 32% of the malignant tumours and 82% (22/27) and 67% of the benign tumours, respectively. In postmenopausal tumours, the positivity for PR in malignant tumours was less frequent (p < 0.01) than that in benign tumours. The tumours in which both aromatase and PR were positive, were less frequent (p < 0.05) in malignant than in benign tumours. Aromatase activity was detected in 100% (8/8) of the PR-positive tumours but in only 68% (9/17) of the PR-negative tumours. With postmenopausal malignant tumours, there was a positive correlation between aromatase activity and PR level (r = 0.77, p < 0.001). However, there was no significant difference in the positivity of ER. The serum steroid levels did not correlate with the tumour levels of aromatase activity, PR or ER. These findings suggest that aromatase activity is correlated with PR in ovarian tumours of postmenopausal women. In addition to steroid receptor status, aromatase activity may be a useful factor in ovarian cancer.

Regulation of very-low-density lipoprotein receptor in hypertrophic rat heart

To elucidate the regulation of very-low density-lipoprotein (VLDL) receptor, we have studied its gene expression in the heart of spontaneously hypertensive rats-stroke prone (SHR-SP, an animal model for hypertension-induced cardiac hypertrophy) compared with Wistar-Kyoto rats. RNase protection assay showed that ventricular VLDL receptor mRNA falls to 41% of normal levels at 4 weeks when hypertension is not yet fully developed, and drops further to 14% at 13 weeks, when cardiac hypertrophy is established. Lipoprotein lipase mRNA decreases in parallel with VLDL receptor mRNA. In cultured neonatal rat ventricular cardiomyocytes, VLDL receptor mRNA decreases in parallel with the process of cardiocyte hypertrophy during the 24 hours after treatment with 10-8 mol/L endothelin-1, falling to 40% of the initial value. These results demonstrate that there is downregulation of VLDL receptor gene expression in cardiac hypertrophy both in vivo and in vitro and suggest that the regulation of the VLDL receptor is possibly linked with the switch in energy substrate from lipid to glucose known to occur in cardiac hypertrophy.

Long survival in small-cell (neuroendocrine) carcinoma of the mediastinum

Extrapulmonary small-cell carcinoma is uncommon. We report a rare case of small-cell carcinoma located in the mediastinum. The patient is still alive 6 years after combined local resection and chemotherapy. This seems to be the first reported case with such long survival.

VLDL receptor in health and disease: interview with a receptor in avian oocytes and mammalian muscle and fat cells

The VLDL receptor is made up of five functional domains that resemble the LDL receptor. In mammals, the receptor is highly expressed in muscle and fat cells, while in chicken, it is abundant in oocytes. The extremely high degree of amino acid conservation of the VLDL receptor during the evolution suggests that the receptor plays an essential role in vertebrates. Recent studies on the chicken VLDL receptor revealed that the receptor plays a key role in the uptake of yolk precursors in oocytes and mediates the growth of oocytes. The VLDL receptor is an essential receptor in avian species and the receptor-deficient mutant hens are sterile and exhibit severe hyperlipidemia with aortic atherosclerosis.

[Immunological effect of recombinant interferon-gamma on tumor infiltrating lymphocytes of renal cell carcinoma--relationship with clinical stage]

We studied the relationship between clinical stage and tumor infiltrating lymphocytes (TIL) in 26 cases of renal cell carcinoma. In 10 patients, interferon-gamma (IFN-gamma) was administered preoperatively (administration group); 5 patients had low stage (Robson < or = I), and the remaining 5 patients had high stage (Robson > or = II) tumors. The other 16 patients underwent nephrectomy alone without preoperative IFN administration (control group); 11 patients had low stage, and the remaining 5 patients had high stage tumors. Immunohistochemical studies of tumor infiltrating lymphocytes in renal cell carcinoma showed a significantly high incidence of CD3, CD8, CD11b and ICAM-1 in the administration group, while CD4, LFA-1 and Ber-MAC3 were increased without significance (p < 0.05). Concerning clinical stage (Robson), a significant increase in CD3, CD8, CD11b and ICAM-1 was observed in the patients with high-stage tumors in the administration group compared to those in the control group (p < 0.05). This suggested that TIL could be changed by preoperative administration of IFN-gamma.

Fecal incontinence successfully managed by antegrade continence enema in children: a report of two cases

Two children with intractable fecal incontinence after correction of high anorectal malformations were successfully managed by the daily administration of a glycerin enema into the cecum via an appendicocecostomy or tubularized cecostomy, according to the method of Malone's antegrade continence enema (ACE). Fluoroscopic defecography performed during this procedure in each patient disclosed that the glycerin enema promptly evoked cecal peristalsis, which was transmitted to the distal colon and rectum, and squeezed out almost all the fecal matter, evacuating it from the anus. However, two enemas within a short interval were required to achieve a complete washout of feces. Although this report describes only two patients, our experience confirmed that the ACE was very effective and that adding the word "continence" to antegrade enema was justifiable. Moreover, fluoroscopic defecography was proven to play a significant role in determining the appropriate regimens of this technique to achieve complete washout of the feces.

[Evaluation of valvular lesions by three-dimensional echocardiography]

A recently developed, on-line image processing system (Tomtec EchoScan) for three-dimensional (3D) echocardiography was compared with conventional two-dimensional examination and our own off-line 3D system. Transesophageal echocardiography was performed in 10 cardiac patients using an omniplane transducer which was automatically rotated under the control of the 3D system. At each angle of the transducer, the respiration-gated image of one cardiac cycle was acquired and transferred into the computer, where the dynamic 3D images of mitral and/or aortic valve were reconstructed. The EchoScan system enabled 3D recognition of the structural and dynamic abnormalities of the valves, such as mitral valve prolapse, although tissue information, which is expressed as a gray scale in the conventional echocardiography, cannot be evaluated from the 3D image. Average times were 5.4 min for the data acquisition, 11.8 min for the 3D processing and 5.7 min for the rendering. Although it seems necessary to improve the efficacy of data acquisition, to shorten the calculation time and to minimize the artifacts, this system enables assessment of 3D cardiac structures at the bedside and to fully recognize valvular lesions preoperatively in patients with valvular heart disease.

Analysis of of the epitopes recognized by mouse monoclonal antibodies directed to Yersinia enterocolitica heat-shock protein 60

To determine amino acid sequences of the epitopes recognized by monoclonal antibodies (mAbs) 3C8 and 5C3 directed against Yersinia enterocolitica heat-shock protein (HSP60), a dot blot analysis was performed using synthesized peptides of Y. enterocolitica HSP60 such as peptides p316-342, p327-359, p340-366, p316-326, p316-321, p319-323, and p321-326 which represent positions of amino acids in Y. enterocolitica HSP60. The dot blot analysis revealed that 5C3 mAb reacted with p316-342, p316-326 and p321-326, and 3C8 mAb p316-342 and p316-326. These results indicate that the epitopes recognized by the mAbs were associated with eleven amino acids, Asp Leu Gly Gln Ala Lys Arg Val Val Ile Asn, of p316-326. The sequence homology between p316-326 of Y. enterocolitica HSP60 and the rest of the HSP60 family suggests that the five amino acids of Lys, Arg, Val, Ile and Asn, which are highly conserved in the HSP60 family, might be related with the epitope recognized by 3C8. In contrast, it was also demonstrated that three amino acids of Leu, Gly and Val, which are not well conserved in the HSP60 family, might be related to the epitope recognized by 5C3.

Molecular diagnosis of hepatitis C viral infection

With the evolution of confirmatory assays for hepatitis C viral infections, bulk populations of unknown hepatitis were diagnosed as hepatitis C virus (HCV)-mediated chronic liver dysfunction throughout the world. More recently, several systems for molecular diagnosis of hepatitis C viral infections were developed. These are commonly performed for efficient antiviral therapy using interferon. Now we are at the crossroads studying hepatitis virology for the development of sensitive and powerful treatment against HCV-mediated chronic liver dysfunction. Here we introduce the current strategy for the advanced diagnosis of hepatitis C viral infection and discuss the exploration of novel hepatitis viruses.

Suppression of Lck protooncogene expression in murine somatic cell hybrids between T lymphoma cells and fibroblasts

Somatic cell hybrids were obtained by cell fusions between Lck-positive EL4 mouse T lymphoma cells and Lck-negative B82 mouse fibroblasts of S194 mouse plasmacytoma cells to examine negative control of lck gene expression in the resulting hybrids. Western blot analysis using a monoclonal antibody against the Lck protein showed a marked decrease in p56lck expression in B82 x EL4 (BEL) hybrids. In contrast to BEL hybrids, the level of p56lck was not changed significantly in S194 x EL4 (SEL) hybrids and was approximately one-half of that seen in EL4 cells. Diminished expression of the Lck protein in BEL hybrids paralleled downregulation of lck mRNA, which was exclusively transcribed from the distal promoter in EL4 cells. It is unlikely that the suppression was simply a consequence of chromosome segregation critical for lck gene expression, since BEL hybrids retained the EL4-derived lck gene and most of the chromosomes from both parental cells. The results from treatment of BEL hybrids with actinomycin D or cycloheximide suggested that suppression of lck gene expression in the hybrids might not be due to posttranscriptional control. DNA methylation status in the lck distal promoter and the coding regions did not appear to correlate with the expression of the gene. Our results suggest that negative control of lck gene expression differs between fibroblasts and B cells, in that lck gene expression in T cells can be shut down by transfer of a putative repressor factor or factors in fibroblasts but not in B cells.

Purification and characterization of bleomycin hydrolase, which represents a new family of cysteine proteases, from rat skin

Bleomycin (BLM) hydrolase, which hydrolyzes the carboxyamide bond in the beta-amino-alanine moiety, was purified from newborn rat skin. The enzyme was purified 2,500-fold over the crude extract to apparent homogeneity in five steps in the presence of 2-mercaptoethanol: 45-55% ammonium sulfate fractionation, followed by chromatographies on Sephacryl S-200, DEAE-cellulofine, Phe-Superose, and Mono Q ion-exchange. The native enzyme had a molecular mass of 280 kDa according to gel filtration. The subunit molecular mass was estimated as 48 kDa by SDS-PAGE, indicating that the enzyme was comprised of six identical subunits. The amino acid sequence of its NH2-terminus was determined to be acetyl-Met-Asn-Asn-Ala-Gly-Leu-Asn-Ser-Glu-Lys-, which was not found in the amino acid sequence database. The optimum pH of the enzyme was 7.5 with pepleomycin (PLM). The Km and Vmax values were 2.1 mM and 6.8 mu mol center dot mg-1 center dot h-1 for PLM, and 1.8 mM and 7.2 mu mol center dot mg-1 center dot h-1 for BLM-A2, respectively. The enzyme activity was inhibited by iodoacetic acid, N-ethylmaleinimide (NEM), and p-chloromercuribenzoic acid (pCMB) as well as divalent cations such as Cu2+, Cd2+, Hg2+, and Zn2+. It was effectively inhibited by a cysteine protease inhibitor E-64. However, cystatins A and C did not inhibit the activity. BLM hydrolase exhibited broad aminopeptidase substrate specificity towards aminoacyl-beta-naphthylamides such as basic, neutral, and hydrophobic amino acid residues, as well as acidic residues. These results indicated that BLM hydrolase represents a new family of cysteine proteases. Western blotting and immunohistochemical analyses showed that BLM hydrolase is ubiquitous in various rat tissues but at low levels in lung and adult skin tissues, suggesting that this enzyme plays an important role in the metabolism of antibiotics.