Prevention by methionine of enhancement of hepatocarcinogenesis by coadministration of a choline-deficient L-amino acid-defined diet and ethionine in rats

The effects of methionine on hepatocarcinogenesis induced by coadministration of a choline-deficient L-amino acid-defined (CDAA) diet and ethionine were examined. F344 male rats were divided into 4 experimental groups. Groups 1 and 2 received the CDAA diet and a choline-supplemented L-amino acid-defined (CSAA)++ diet, respectively. Group 3 received the CDAA diet containing 0.05% ethionine, and group 4 the CDAA diet containing 0.05% ethionine and 0.47% methionine. Animals were killed after 12 weeks of treatment. Histologically, the CDAA diet induced intracellular fat accumulation and foci. In contrast, ethionine caused not only foci, but also hyperplastic nodules, cholangiofibrosis and the proliferation of oval cells without such fat accumulation. Methionine abolished the development of all of the liver lesions induced by coadministration of the CDAA diet and ethionine. To investigate the effects of methionine on induction of c-myc and c-Ha-ras expression, as well as generation of 8-hydroxyguanine (8-OHGua) and 2-thiobarbituric acid-reacting substances (TBARS), by coadministration of the CDAA diet and ethionine, subgroups of 3 to 5 animals were killed at 2, 4, 8, or 11 days after the beginning of the experiment. Coadministration of the CDAA diet and ethionine markedly enhanced the level of expression of c-myc and c-Ha-ras, 8-OHGua formation and TBARS generation as compared with the CDAA or CSAA diet within 11 days, and methionine blocks these actions. These results indicate that addition of methionine prevents the induction of c-myc and c-Ha-ras expression, 8-OHGua formation and TBARS generation, as well as hepatocellular lesions, by coadministration of the CDAA diet and ethionine in rats, and suggest a possible involvement of oxidative stress and gene expression in hepatocarcinogenesis by these agents.

Correlation between the differences in the free energy change and conformational energy in the folded state of hen lysozymes with Gly-Pro and Pro-Gly sequences introduced to the same site

We suggested for the introduction of a prolyl residue into a protein that if the N-terminus residue is glycine, an unfavorable interaction in the folded state caused by the introduction of the prolyl residue can be substantially avoided by use of mutant lysozymes in which Gly-Pro and Pro-Gly sequences are introduced to positions 101-102 in the loop region of the lysozymes [Ueda, T., Tamura, T., Maeda, Y., Hashimoto, Y., Miki, T., Yamada, H., and Imoto, T. (1993) Protein Eng. 6, 183-187]. In order to determine whether or not the information obtained is applicable to other regions, we prepared mutant lysozymes with Gly-Pro and Pro-Gly sequences at position 47, which is located in the beta-sheet, positions 70-71, which are located in the loop, positions 117-118, which are located in the beta-turn, and positions 121-122, which are located in the 3(10)-helix. The free energy changes of the native and mutant lysozymes for unfolding were determined at pH 5.5 and 35 degrees C. However, a mutant lysozyme with the Gly-Pro sequence was not always stabler than that with the Pro-Gly sequence at the same site. On the other hand, in order to determine whether or not strain caused by these sequences exists in the folded or unfolded state, the structures of these mutant lysozymes were determined by use of energy minimization. On comparison of the differences in the free energy change between the mutant lysozymes with Gly-Pro and Pro-Gly sequences at the same site with those in their total local conformational energies, it was found there is a good correlation between them. Therefore, it was suggested that the difference in total local conformational energy caused by the introduction of a Gly-Pro or Pro-Gly sequence could be estimated by use of the energy minimized structure. Moreover, the correlation indicated that the differences in the free energy change between Gly-Pro and Pro-Gly lysozymes may be reflected by the differences in the total local conformational energies in their folded state. It was suggested that the energy levels in the unfolded states of mutant lysozymes with Gly-Pro and Pro-Gly sequences at the same site in a Gdn-HCl solution were almost identical.

Changes in laminin content in livers of patients with alcoholic liver disease

An increase in serum laminin levels has been reported in patients with liver disease; however, the mechanisms for this increase have not yet been clarified. In the present study, the laminin content of liver biopsy specimens obtained from patients with alcoholic liver disease and non-alcoholic liver disease was determined with a one-step sandwich enzyme-immunoassay system, using monoclonal antibodies for human placental laminin. Hepatic laminin content was significantly higher in patients with liver disease than in normal controls. In alcoholic liver disease, the content in patients with mild fibrosis was lower than in patients with advanced types of alcoholic liver disease. In non-alcoholic liver disease, the hepatic laminin content tended to increase in parallel with the progression of fibrosis. The laminin content in alcoholic liver disease was significantly higher than in the corresponding type of non-alcoholic liver disease. The ratio of laminin to total collagen content was highest in alcoholic liver disease showing mild fibrosis and decreased in parallel with the progression of fibrosis. In contrast, the ratio was low in all types of nonalcoholic liver disease. The ratio in patients with alcoholic liver disease was significantly higher than these with the corresponding non-alcoholic liver disease. Hepatic laminin content increased in parallel with the increase in hepatic type IV collagen in alcoholic liver disease, and the correlation was statistically significant. However, similar correlation was not found in non-alcoholic liver disease. These results indicate that the response to laminin synthesis to alcoholic liver disease is strong in mild fibrosis and reached a plateau at a relatively early stage of fibrosis. The stimulation for laminin synthesis in non-alcoholic liver disease is different from that in alcoholic liver disease.

Effects of docosahexaenoic acid (DHA) on intestinal polyp development in Apc delta 716 knockout mice

Epidemiological studies and animal experiments show an association of dietary intake of fish oils and low incidence of several types of cancers. The active ingredients of fish oils appear to be polyunsaturated fatty acids of omega-3 type such as eicosapentaenoic acid and docosahexaenoic acid (DHA). We have investigated chemopreventive effects of DHA on mouse intestinal polyposis using adenomatous polyposis coli (Apc) gene knockout mice. Damage to the human APC gene is responsible for not only familial adenomatous polyposis but also many sporadic cancers of the entire digestive tract. Using homologous recombination in embryonic stem cells, we recently constructed gene knockout mice containing a truncation mutation in the Apc gene at codon 716 (Apc delta 716). The heterozygous mice developed numerous intestinal polyps, and all microadenomas dissected from the earliest polyps had already lost the wild-type allele, indicating the loss of heterozygosity [Oshima et al. (1995), Proc. Natl Acad. Sci. USA, 92, 4482-4486]. We fed Apc delta 716 heterozygotes with AIN-76A purified diet containing 3% DHA for 7 weeks, and scored the number and size of intestinal polyps. Average DHA intakes per day were 4.1 and 4.3 g/kg body wt for males and females, respectively. DHA-fed females had only 31% of polyps compared with the control females that developed about 220 polyps, whereas DHA-fed females showed no significant decrease in the polyp number. As for the polyp size, the proportion of larger polyps decreased more significantly in females than in males. This is the first demonstration that DHA inhibits intestinal polyposis induced by an Apc mutation at both its formation and growth.

Ki-ras mutations and p53 protein expressions in intrahepatic cholangiocarcinomas: relation to gross tumor morphology

BACKGROUND & AIMS

We previously reported that intrahepatic cholangiocarcinomas (ICCs) can be divided into three categories according to their gross appearance with possible links to biological behavior. Ki-ras and p53 gene alterations are thought to be involved in early and late phases of carcinogenesis, respectively. This study was performed to investigate the relationship between the gross appearance and genetic alterations of ICC.

METHODS

We examined 21 patients with ICC. Ki-ras point mutations were assessed by polymerase chain reaction/single-strand conformation polymorphism methods followed by direct DNA sequencing. Expressions of p53 protein were immunohistochemically assessed.

RESULTS

Ki-ras point mutations were found in 10 patients (48%), and expressions of p53 protein were detected in 4 (19%). Applying the gross classification that we previously proposed, Ki-ras mutations were prominent in the periductal extension type (4 of 6; 67%) and the spicula-forming type (6 of 10; 60%). On the other hand, none of the five mass-forming-type tumors harbored Ki-ras mutations. Expressions of p53 protein did not show any clear association with gross appearance.

CONCLUSIONS

Ki-ras gene alterations may be involved in the cholangiocarcinogenesis of periductal extension and spicula-forming but not mass-forming types, suggesting that the underlying processes of development are different.

Initiation of hepatocarcinogenesis by endogenously formed N-nitrosobis(2-hydroxypropyl)amine, N-nitrosodiethanolamine and N-nitroso-2,6-dimethylmorpholine in rats

Initiation activities of endogenously formed N-nitrosobis(2-hydroxypropyl)amine (NBHPA), N-nitrosodiethanolamine (NDELA) and N-nitroso-2,6-dimethylmorpholine (NDMM) were investigated in a modified short-term assay for rat hepatocarcinogenesis. Male Wistar rats were fed 1% bis(2-hydroxypropyl)amine, 0.5% diethanolamine or 0.25% 2,6-dimethylmorpholine in the diet plus 0.3% sodium nitrite in the drinking water. Two weeks after starting the experimental regimen they underwent 2/3 partial hepatectomy and were then maintained on the respective diets for a further week. Following a 2 week recovery period on basal diet rats were subjected to a resistant hepatocyte regimen consisting of 0.02% 2-acetylaminofluorene in the diet for 2 weeks and 1 mg carbon tetrachloride/kg body wt by gavage at the midpoint. Initiation activity was assayed by measuring hepatic foci positive for gamma-glutamyltranspeptidase. Numbers of such foci per cm2 were significantly increased in the groups given the secondary amines together with nitrite compared with values for groups given each precursor or nitrite alone. Further, the numbers of lesions were essentially similar to those found in rats given carcinogenic doses of NBHPA, NDELA and NDMM. The results clearly of demonstrate hepatocyte initiation activities of endogenously formed carcinogens, presumably NBHPA, NDELA and NDMM.

National survey of alcoholic liver disease in Japan (1968-91)

National surveys of alcoholic liver disease (ALD) in Japan were performed in 1978 and 1985 by a previous Japanese study group for ALD (the Takeuchi group). In the present study, a subsequent nationwide survey of ALD in Japan was conducted from 1986 to 1991 and the results compared with the previous studies. In order to clarify the aetiological relationship between hepatitis C virus (HCV) infection and ALD, results were also analysed according to new diagnostic criteria for ALD proposed by the current ALD study group (the Takada group). According to the diagnostic criteria of the Takeuchi group, the incidence of ALD did not differ significantly from 1986 to 1991. However, the incidence of hepatocellular carcinoma (HCC) in alcoholic cirrhosis (AL-LC) clearly increased during this period. The analysis, which included analysis of results from the previous studies, indicated that the incidence of ALD reached a plateau in 1980 and then stabilized. However, HCC in AL-LC continued to show a linear increase from 1976 to 1991. The new diagnostic criteria of the Takada group were used to analyse cases from 1990 and 1991. Approximately two out of every three cases of ALD were caused by alcohol alone, and the remainder were caused by a combination of alcohol and HCV. Cases caused only by HCV were very rare. The main aetiology in patients with alcoholic hepatitis and fibrosis was alcohol alone, and in the case of chronic hepatitis, in heavy drinkers, it was a combination of alcohol and HCV. In half the patients with AL-LC the aetiology was alcohol alone, and in the other half it was a combination of both alcohol and HCV. In the majority of patients with HCC, the aetiology was a combination of alcohol and HCV, indicating that HCV infection may be important in the development of HCC in alcoholics.

[Prognosis after radical surgery in prostatic cancer patients with lymph nodes metastases]

We investigated prognosis of clinically localized prostatic adenocarcinoma patients who revealed to have had lymph nodes metastases by undergoing radical surgery. Eighty six patients were operated during the last 15 years under the clinical diagnosis of A2, 9 patients, B1, 15 B2, 13 and C, 49, respectively. Total prostatectomy was done to 51, total cystoprostatectomy to 33 and total pelvic excentration to 2 patients. Of these patients, 22.2% with stage A2, 20.2% with B1, 7.7% with B2 and 43.8% with C had positive nodes and the rate of positive nodes in stage C was significantly higher than that in other stages (p < 0.01). Regarding histological differentiation, 15.4% of well, 23.7% of moderate and 51.6% of poor by differentiated had positive nodes and the rate of positive nodes in poor by differentiated was significantly higher (p < 0.01). In 2 of 21 cases whose lymph nodes were dissected to the level of the aortic bifurcation, positive nodes were detected only in the external and common iliac areas. These two cases were missed, i.e., "false negative" if limited nodes dissection was performed. All patients with positive nodes were treated with hormonal therapy. The 5-year cancer specific survival rate of patients with positive (n = 27) and negative (n = 59) nodes were 66.4% and 92.4%, respectively. The prognosis of patients with positive nodes were significantly worse than that of patients with negative nodes (p < 0.001). Among 27 patients with positive nodes, significant prognostic factor was not number or extent of positive nodes, but histological differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

p53 mutation without allelic loss and absence of mdm-2 amplification in a transplantable hamster pancreatic ductal adenocarcinoma and derived cell lines but not primary ductal adenocarcinomas in hamsters

An investigation of p53 gene mutation by single-stranded conformation polymorphism analysis of polymerase chain reaction products followed by direct sequencing and of murine double minute 2 (mdm-2) gene amplification by Southern blot analysis was performed, using a series of hamster pancreatic duct adenocarcinomas: 18 primary adenocarcinomas induced by N-nitrosobis(2-oxopropyl)amine, a transplantable adenocarcinoma (HPD), and three cell lines derived from HPD (HPD1NR, HPD2NR, and HPD3NR). A mutation in the p53 gene was detected at codon 197, resulting in an amino acid change from leucine to phenylalanine, in both HPD and the three cell lines but in none of the 18 primary adenocarcinomas. In the three HPD cell lines, which were confirmed to contain only cancer cells, a normal p53 gene allele was retained. Immunohistochemical investigation of p53 expression using polyclonal antibody Ab-7 revealed positive nuclear staining in the HPD and two back-transplanted tumors derived from HPD1NR and HPD2NR but not in the 18 primary adenocarcinomas. mdm-2 gene amplification was not detected in 18 primary adenocarcinomas or any of the tumor cell lines. The results suggest that a p53 gene mutation without allelic loss, together with overexpression of p53 protein, may be a genetic alteration involved in the progression stage of multistep pancreatic carcinogenesis in hamsters and that mdm-2 gene amplification is not important for this process.

Efficacy of combination therapy with interferon and azidothymidine in chronic type C hepatitis: a pilot study

The effects of interferon are seen in only a limited number of patients with hepatitis C virus (HCV) of the K1 type, indicating that a combination therapy with other antiviral drugs may be essential to obtain better results. In the present pilot study, the effects of combination therapy with interferon (IFN) and an antiviral drug azidothymidine (AZT) were analyzed. The combination therapy was conducted in 22 patients with chronic hepatitis C after obtaining their informed consent (combination group). Three or six million units of natural IFN alpha was administered daily for 3 weeks and then three times a week for 21 weeks. Combination therapy was initiated at the beginning of the 8th week of IFN treatment, 500 mg of AZT per day being given for 8 weeks. As a control, changes in HCV-RNA were also analyzed in patients treated with interferon alone (IFN-alone group). At the end of the treatment, blood was negative for HCV in 32.5% of the IFN-alone group and in 50.0% of the combination group, the difference not being significant. However, in patients with HCV-K1, HCV-negative rates were 14.2% in the IFN-alone group and 45.5% in the combination group, showing a significant difference. In patients with other HCV genotypes, HCV-negative rates did not different between the two groups. These results suggest that combination therapy with IFN and AZT may be an effective treatment for chronic type C hepatitis caused by the K1 type virus, although further studies on larger number of patients will be needed to obtain definite conclusions.

Evidence against dominant negative mechanisms of intestinal polyp formation by Apc gene mutations

Mutations in the adenomatous polyposis coli (APC) gene are responsible for not only familial adenomatous polyposis but also many sporadic cancers of the digestive tract. Most mutations found in familial adenomatous polyposis patients are of the truncation type, and the phenotype is affected by the mutation sites in the gene. Truncated APC proteins can associate with the wild-type protein. Accordingly, it has been proposed that the polyposis is caused by a dominant negative mechanism. To test this possibility, we constructed transgenic mice that contained mutant minigenes. They expressed the APC protein truncated either at codon 716 (Apc delta 716) or 1287 (Apc delta 1287) at high levels in the intestinal epithelium. Contrary to our expectation, no intestinal polyps or tumors were found in any of such mice, even after 7 months. These results rule out any dominant negative mechanisms in which the truncated APC protein is directly involved in the formation of intestinal polyps in the mouse.

Relationship between respiratory muscle strength and lean body mass in men with COPD

It has been suggested that low body weight may be associated with decreased respiratory muscle function in COPD, but the precise mechanism is not known. Since body compositional change inevitably accompanies body weight change, we decided to study the possible relationship between respiratory muscle strength and body composition in patients with COPD. We studied respiratory muscle strength, pulmonary function, and body composition in 24 Japanese male patients with COPD. Patients were divided into two groups according to their body weight (group A, body weight lower than 80% of ideal body weight vs group B, 80% or more) and a comparison was made together with age-matched controls (group C). Maximal inspiratory mouth pressure (PImax) and maximal expiratory mouth pressure (PEmax) were measured by a previously reported method. Body compositional analysis was performed using dual energy x-ray absorptiometry (DXA; Norland XR26). It showed significantly lower fat body mass (FAT), FAT/body weight%, and lean body mass (LEAN) in group A than those in group B. The PImax in group A was significantly lower than that in group B and C (44.2 +/- 13.8, 76.4 +/- 29.9, and 88.6 +/- 18.1 cm H2O, respectively). PEmax in group A was also significantly lower than that in group B and group C (61.9 +/- 20.1, 86.7 +/- 26.8, and 90.4 +/- 17.6 cm H2O, respectively). Both PImax and PEmax were significantly correlated with LEAN (r = 0.656, r = 0.591, p < 0.01, respectively) in patients with COPD. These results show that respiratory muscle strength is closely associated with body weight and lean body mass in patients with COPD. The present approach to compare respiratory muscle strength with lean body mass should be useful for studying the mechanism of respiratory muscle weakness in patients with COPD.

The role of angiogenesis in the tumor growth of Syrian hamster pancreatic cancer cell line HPD-NR

BACKGROUND/AIMS

New therapeutic approach is required for pancreatic cancer, one of the most intractable malignancies. The role of angiogenesis in the tumor growth of a Syrian hamster pancreatic cancer cell line HPD-NR, which closely resembles its human counterpart, was investigated.

METHODS

Angiogenic activity was measured as stimulation of growth of human umbilical vein endothelial cells (HUVEC), and angiogenic factors produced by HPD-NR cells were identified by reverse-transcription polymerase chain reaction and Northern blot analysis. Then in vitro and in vivo antitumor effects of a potent angiogenesis inhibitor, O-(chloroacetylcarbamoyl)fumagillol (AGM-1470), were examined.

RESULTS

The conditioned medium of HPD-NR cells stimulated the growth of HUVEC, and four hamster angiogenic factors were detected with an overexpression of transforming growth factor alpha and vascular endothelial growth factor messenger RNAs. AGM-1470 specifically inhibited the growth of HUVEC and that of HPD-NR tumors in vivo with decreased vascularity of the tumors but not the growth of HPD-NR cells in vitro.

CONCLUSIONS

The results suggest that angiogenesis plays an important role in tumor growth of HPD-NR cells and can be a new target of medical therapy for pancreatic cancer.

Establishment of a myeloid leukaemic cell line (SKNO-1) from a patient with t(8;21) who acquired monosomy 17 during disease progression

A novel cell line SKNO-1 was established from the bone marrow cells of a 22-year-old male suffering from acute myeloblastic leukaemia (AML) M2 with t(8;21) whose disease became resistant to chemotherapy after acquisition of 17 monosomy. SKNO-1 has been maintained for more than 36 months as a granulocyte-macrophage colony-stimulating factor (GM-CSF) dependent line. Morphologically, SKNO-1 cells were myeloblasts somewhat matured. The cells grow in suspension with a doubling time of 48-72 h. The survival and growth of SKNO-1 cells was absolutely dependent on granulocyte-macrophage colony stimulating factor (GM-CSF). SKNO-1 cells possessed t(8;21) and monosomy 17 which were observed in original leukaemic cells. We confirmed that the AML1 gene, located on chromosome 21, was rearranged and the AML1-MTG8 fusion transcript was expressed in SKNO-1 cells. Over-expression and mutation of the p53 gene were also detected in SKNO-1. It is likely that alterations of AML1 or MTG8 gene and p53 gene contribute to a disease progression in this case. Since t(8;21) translocation is a common chromosome abnormality in AML, and inactivation of the p53 gene may play a crucial role in disease progression in AML, SKNO-1 would be a useful tool for analysing the molecular mechanisms in myeloid leukaemogenesis.

Efficacy of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl)fumagillol (AGM-1470) on osteosarcoma growth and lung metastasis in rats

The efficacy of the anti-angiogenic agent, O-(chloroacetyl-carbamoyl)fumagillol (AGM-1470), against primary tumor growth and spontaneous lung metastasis was evaluated experimentally using a transplantable osteosarcoma line in rats previously established in our laboratory. Male Fischer 344 rats bearing the tumor with a high potential for metastasis received intermittent or continuous subcutaneous administrations of AGM-1470. Both treatment regimens resulted in significant inhibitions of spontaneous lung metastasis and primary tumor growth in a dose-dependent manner, with continuous administration of AGM-1470 exerting the most pronounced inhibitory effects on both parameters.

Inhibitory effects of sulfation inhibitors on initiation of pancreatic ductal carcinogenesis by N-nitrosobis(2-oxopropyl)amine in hamsters

The effects of dehydroepiandrosterone sulfate (DHAS), a typical hydroxysteroid sulfotransferase (HSTase) inhibitor, and of 3'-phosphoadenosine 5'-phosphate (PAP), a nonspecific sulfation inhibitor on N-nitrosobis(2-oxopropyl)-amine (BOP)-induced initiation were examined in a rapid production model for pancreatic carcinomas in hamsters in order to elucidate the involvement of sulfotransferase in the metabolic activation of beta-oxypropylnitrosamines. While neither low nor high doses of DHAS and PAP exerted any significant influence on the incidence of ductal lesions including carcinomas, the high dose of DHAS (350 mg/kg body wt) and a both low (90 mg/kg) and high (180 mg/kg) doses of PAP reduced the mean numbers of pancreatic ductal adenocarcinomas. The high dose of PAP also reduced the number of all ductal lesions combined. The results thus suggest that metabolic activation with STase is involved in BOP-induced pancreatic ductal carcinogenesis in hamsters, and support the hypothesis that BOP is metabolized to beta-hydroxyalkylnitrosamines followed by activation to proximate sulfuric acid esters by HSTase.

Translational regulation of the gonadotropin-releasing hormone receptor in alpha T3-1 cells

Prolonged exposure of the GnRH receptor to high concentrations of GnRH leads to receptor down-regulation. The role of altered receptor biosynthesis in this agonist-induced receptor down-regulation was investigated in the mouse gonadotrope cell line, alpha T3-1 cells. After exposure to 1 microM GnRH for 24 h, the number of GnRH receptor-binding sites in alpha T3-1 cells decreased to 25 +/- 6% of the control levels. No corresponding changes were observed in GnRH receptor messenger RNA (mRNA) using either quantitative ribonuclease protection/solution hybridization assay or Northern blot analysis. However, when the ability of this RNA to direct the synthesis of functional GnRH receptors was examined by quantitative assessment of the voltage clamp response in Xenopus oocytes, GnRH-induced currents in oocytes injected with RNA isolated from down-regulated cells was reduced to 40 +/- 13% of the response obtained after the injection of RNA from control alpha T3-1 cells. Thus, although GnRH receptor mRNA levels were not altered, the ability of cellular RNA isolated from alpha T3-1 cells to direct the synthesis of functional GnRH receptors was regulated in concert with receptor binding. To investigate the possibility that GnRH receptor mRNA translational efficiency was reduced, the distribution of polyribosome-associated GnRH receptor mRNA was studied. Polyribosome-associated mRNA was separated by linear sucrose gradient, and GnRH receptor mRNA distribution was determined by ribonuclease protection assay. GnRH receptor mRNA distribution shifted from the largest to smaller polyribosome and monosome fractions in cells exposed to GnRH compared to controls. The weighted mean of GnRH receptor mRNA distribution among eight fractions shifted from fraction 5.924 +/- 0.06 in control polysomes to fraction 5.45 +/- 0.219 for polysomes from down-regulated cells (P < 0.05). These results demonstrate that GnRH receptor down-regulation is accompanied by decreased GnRH receptor mRNA translation in the absence of any change in GnRH receptor mRNA levels. These data suggest that decreased efficiency of GnRH receptor mRNA translation contributes to the down-regulation of this receptor in alpha T3-1 cells.

Microstructures in high-Tc Bi(Pb)-family 2212 superconductors as revealed by scanning and transmission electron microscopy

Microstructures of Bi(Pb)-family 2212 superconductors, which were prepared by a sol-gel method with three different compositions, were examined mainly by scanning and transmission electron microscopy. The magnetization of the specimens strongly depends on the ratio between Bi and Pb content, while Tc is almost constant. In specimen 1, prepared with the nominal composition of Bi/Pb = 9/1, small grains of 2212 phase are formed with a minor fraction of some impurity phases. In specimen 2, with Bi/Pb = 17/3, which is optimum from the viewpoint of magnetization, large grains of the 2212 phase are formed during heating at 800 degrees C, also with the impurity phases. In specimen 3, with Bi/Pb = 8/2, the 2212 grains are divided by layers of (Bi0.86, Pb0.14) (Ca0.7, Sr0.3)Ox. Moreover, plate-like 2212 crystals are severely bent so that small cracks appear often with an inclusion of amorphous substance being rich in Ca and Pb. These layers and cracks must degrade the magnetization. A modulated structure of Bi-type is formed in the 2212 grains of specimens 1 and 2, while not only Bi-type but also Pb-type are formed in specimen 3. The wavelength of Bi-type is different for each specimen.

Menopause-related changes in bone mineral density in Japanese women: a longitudinal study on lumbar spine and proximal femur

We investigated 2-year longitudinal changes of bone mineral density (BMD) in lumbar spine and proximal femur in 64 Japanese women aged 38-67. Forty subjects were premenopausal (mean age 44.9) and 24 postmenopausal (mean age 54.6) at enrollment of the study. Six subjects experienced menopause during the 2-year study period and were defined as the perimenopausal group. Measurements of BMD were performed using dual-energy X-ray absorptiometry at L2-4, femoral neck, greater trochanter, and Ward's triangle. Paired t test revealed no significant decrease in BMD at any site in the premenopausal group. Significant annual decrease in BMD was observed in the perimenopausal group at L2-4, femoral neck, and greater trochanter. A similar tendency was observed in Ward's triangle, but did not reach statistical significance. In the postmenopausal group, significant decrease in BMD was found at the proximal femur, but not at L2-4. Significant inverse correlation between age and change rate of BMD was found at L2-4, but not at the proximal femur, in premenopausal women. In postmenopausal women, there was a significant association between body weight (BW) change and change rate in BMD at L2-4, femoral neck, or greater trochanter. This association was not found in the premenopausal group. These results suggest that effect of menopause on BMD may be different in individuals and sites of the skeleton. BW change may affect change in BMD in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

High rates of Ki-ras point mutation in both intra- and extra-hepatic cholangiocarcinomas

The presence of the Ki-ras gene mutations in 14 cases of intrahepatic cholangiocarcinoma (IHC) and nine cases of extrahepatic cholangiocarcinoma (EHC) were investigated by polymerase chain reaction-single strand conformation polymorphism analysis. To obtain enriched tumor cell DNA, the microdissection method was used on formalin-fixed paraffin-embedded tissue sections. Point mutations at codon 12 of the Ki-ras gene were detected in seven (50%) of the 14 cases of IHC and six (67%) of the nine EHC cases. In all but one of the ras gene mutation cases, G to A transitions in the second position of codon 12 were detected, the exception being a G to T transition in the same position in one IHC. No point mutations were detected at codon 13 or 61 in either IHC or EHC. Furthermore, there was no demonstrable correlation between Ki-ras mutation and patient age, tumor Stage, histological findings or prognosis. The present results demonstrated a higher participation of Ki-ras gene mutations in EHC than found in previous studies, and provided a confirmation and extension of the results earlier reported by Tada et al. and Tsuda et al. for IHC.

Genetic polymorphisms of cytochrome P4502E1 related to the development of alcoholic liver disease

BACKGROUND/AIMS

Because heavy drinkers do not always develop alcoholic liver disease (ALD), genetic factors may be involved. Cytochrome P4502E1 is the main enzyme that oxidizes ethanol in the non-alcohol dehydrogenase pathway. Recently, the presence of genetic polymorphisms of this enzyme was confirmed. In the present study, the genotypes of P4502E1 were analyzed in patients with or without ALD.

METHODS

After extraction of DNA from white blood cells, genotypes of P4502E1 were determined by restriction fragment length polymorphisms using two endonucleases. The genotypes were separated into three types: type A, type C (homozygous for the c1 or c2 gene), and type B (heterozygous for both genes).

RESULTS

In 50 patients with ALD, the prevalence of type A was 16% and that of the c2 gene was 84%. The genotypes in 10 heavy drinkers without ALD were all type A. In 34 patients with non-alcoholic liver disease and in 88 patients without hepatobiliary disease, the prevalence of type A was 65% and 71%, respectively, indicating a significantly higher prevalence of the c2 gene in ALD. In healthy nonalcoholics, the prevalence of type A was 62%-68%.

CONCLUSIONS

These results suggest that polymorphisms of P4502E1 may be related to the development of ALD.

Full-length sequence of the genome of hepatitis C virus type 3a: comparative study with different genotypes

Hepatitis C virus (HCV) type K3a (type 3a), which represents a minor genotype in Europe, the U.S.A. and Asia, appears to be significantly distributed throughout Australia and Brazil. We amplified the HCV-K3a/650 genome by reverse transcription polymerase chain reaction in ten overlapping fragments and determined the nucleotide sequences. The total sequence was 9454 bases in length and contained an open reading frame of 3021 amino acids, which is 10 or 11 amino acids longer than in HCV type 1 and 12 amino acids shorter than the sequence of type 2. These differences were due to the different lengths of both the putative envelope protein E2 and the NS5A regions, whose nucleotide lengths differ between types 1 and 2 also. Phylogenetic analysis of the putative core region and a portion of NS5B encoding the Gly-Asp-Asp motif indicated that HCV-K3a closely matched the corresponding type 3a group. The deletion and addition of amino acids in both E2 and NS5A may be associated with their pathobiological features.