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S Akiba

Publications and source records attributed to S Akiba.

At least 19 recordsLinked to original sources

Mobile phone use and acoustic neuroma risk in Japan.

OBJECTIVES: The rapid increase of mobile phone use has increased public concern about its possible health effects in Japan, where the mobile phone system is unique in the characteristics of its signal transmission. To examine the relation between mobile phone use and acoustic neuroma, a case-control study was initiated. METHODS: The study followed the common, core protocol of the international collaborative study, INTERPHONE. A prospective case recruitment was done in Japan for 2000-04. One hundred and one acoustic neuroma cases, who were 30-69 years of age and resided in the Tokyo area, and 339 age, sex, and residency matched controls were interviewed using a common computer assisted personal interview system. Education and marital status adjusted odds ratio was calculated with a conditional logistic regression analysis. RESULTS: Fifty one cases (52.6%) and 192 controls (58.2%) were regular mobile phone users on the reference date, which was set as one year before the diagnosis, and no significant increase of acoustic neuroma risk was observed, with the odds ratio (OR) being 0.73 (95% CI 0.43 to 1.23). No exposure related increase in the risk of acoustic neuroma was observed when the cumulative length of use (<4 years, 4-8 years, >8 years) or cumulative call time (<300 hours, 300-900 hours, >900 hours) was used as an exposure index. The OR was 1.09 (95% CI 0.58 to 2.06) when the reference date was set as five years before the diagnosis. Further, laterality of mobile phone use was not associated with tumours. CONCLUSIONS: These results suggest that there is no significant increase in the risk of acoustic neuroma in association with mobile phone use in Japan.

Adult↗

Group IVA phospholipase A2-mediated production of fibronectin by oxidized LDL in mesangial cells.

The deposition of atherogenic lipoproteins such as oxidized low-density lipoprotein (oxLDL) within the mesangium is involved in the overproduction of extracellular matrix proteins, a key event in the progression of glomerular diseases including glomerulosclerosis. To clarify the mechanisms underlying the oxLDL-induced production of extracellular matrix proteins, we examined the possible involvement of group IVA phospholipase A(2) (PLA(2)) using human mesangial cells and group IVA PLA(2)-deficient mouse mesangial cells. oxLDL accelerated the production of fibronectin and collagen (type IV), components of extracellular matrix proteins, with the preceding release of arachidonic acid. Methyl arachidonyl fluorophosphonate (MAFP), known as an inhibitor of group IVA PLA(2), markedly suppressed the oxLDL-induced production of fibronectin as well as the release of arachidonic acid, whereas it did not inhibit the production of collagen. The inhibitory effect of MAFP on the production of fibronectin was reversed by adding arachidonic acid and 12-hydroxyeicosatetraenoic acid. Furthermore, we found that in group IVA PLA(2)-deficient mouse mesangial cells, the production of fibronectin in response to oxLDL was weak as compared with that in wild-type cells. However, the production by oxLDL of collagen was not suppressed in the group IVA PLA(2)-deficient cells. These findings suggest that group IVA PLA(2) is involved in the production of fibronectin in oxLDL-stimulated mesangial cells.

Arachidonic Acid↗

Nasal natural killer/T-cell lymphoma and its association with type "i"/XhoI loss strain Epstein-Barr virus in Chile.

BACKGROUND: Nasal T/natural killer (NK)-cell lymphoma is an aggressive type of non-Hodking's lymphoma associated with Epstein-Barr virus (EBV) and striking geographical variations worldwide. AIM: To characterise nasal NK/T-cell lymphoma associated with genotypes of EBV in Chile, a Latin American country, where multiple strains of EBV, including two new recombinant strains, in healthy individuals were recently found. METHODS: Cases with diagnosis of primary nasal lymphoma were selected for histological and immunohistochemical analysis (CD3, CD3e, CD4, CD8, CD79a, CD56, CD57 and TIA-1) and in-situ hybridisation, serology and genotyping analysis for EBV. RESULTS: Out of 22 cases, 9 (41%) cases fulfilled the World Health Organization criteria for nasal NK/T-cell lymphoma; of these 7 (78%) cases were positive for EBV. Genotyping analysis revealed 6 cases of type 1 EBV and wildtype F at the BamHI-F region, 4 cases type "i" EBV at the BamHI-W1/I1 region; XhoI wild type was found in 2 and XhoI loss in 4 cases, respectively. Cosegregation analysis of the BamHI-W1/I1 region and XhoI restriction site showed the new recombinant strain type "i"/XhoI loss in 3 cases and type "i"/XhoI wild-type strain in 1 case. Most patients were treated with combined anthracycline-containing regimens. Half of the cases attained complete remission. CONCLUSION: Although nasal NK/T-cell lymphomas from Chile share similar clinicopathological features, high association with EBV and unfavourable prognosis with those described elsewhere, genotype analysis shows that the new recombinant type "i"/XhoI loss strain might contribute to explain the intermediate incidence of nasal NK/T-cell lymphomas in Latin America.

Adult↗

Epstein-Barr virus-associated gastric carcinoma in Lima, Peru.

We examined 254 gastric carcinomas (GCs) diagnosed in four hospitals in Lima, Peru, and its suburban area during the period between 1994-2001. Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) was identified by the in situ hybridization (ISH) technique to detect EBV-encoded small RNA (EBER) in gastric tissue. EBVaGCs, where EBER ISH staining was observed in all carcinoma cells, accounted for 3.9% (10/254) of gastric adenocarcinomas, the lowest frequency ever reported in Latin American countries. EBVaGC incidence rates in Peru, which we estimated on the basis of the present study and cancer incidence in Lima, were 0.8 per 100,000 among men and 0.5 per 100,000 among women. These estimates are much lower than those reported in our previous studies in Colombia (4.1 and 1.4 per 100,000 among men and women, respectively), a neighboring country, and in Japan (6.4 and 1.1 per 100,000 among men among women, respectively). Interestingly, EBVaGC in Peru showed no evident male predominance, as opposed to the findings reported in a majority of studies. Other clinicopathological features of EBVaGC in Peru were similar to those found in literature: EBVaGC showed no age dependence, a predominance in the non-antrum part of the stomach, and high frequencies in histological subtypes of moderately differentiated tubular adenocarcinoma and solid poorly differentiated adenocarcinoma. There was a case of well-differentiated adenocarcinoma showing a partial EBER-1-positive staining. In this carcinoma, the tumor in the body (middle third of the stomach) was EBER-1 positive but the tumor in the stomach antrum showed no noticeable EBER-1 ISH staining. We suspect this was a case of synchronous double carcinomas. Further studies are needed to identify the cause of the low frequency and lack of male predominance of EBVaGC in Peru.

Aged↗

Epstein-barr virus detection in tumors of upper gastrointestinal tract. An in situ hybridization study in Pakistan.

To examine the potential role of Epstein-Barr virus (EBV) in the carcinogenesis of upper gastrointestinal tract, we conducted an in situ hybridization assay for EBV-encoded small RNA (EBER) expression in the tumors of 56 oral and 50 esophageal squamous cell carcinoma (SCC) cases, and 52 stomach adenocarcinoma cases diagnosed in the King Edward Medical College and Allama Iqbal Medical College Lahore, Pakistan between 1996-2002. There were no malignancies with positive EBER expression in oral and esophageal SCC. Only one out of the 52 gastric adenocarcinoma cases (1.9%) was positive for EBER expression, and this frequency was relatively low as compared to cases reported worldwide. The case was a 42 year-old male patient and histologically classified as moderately differentiated tubular adenocarcinoma. In conclusion, the frequency of EBV-associated gastric carcinoma was relatively low in Pakistan. The present study could not confirm the involvement of EBV in the carcinogenesis of oral and esophageal SCC.

Adenocarcinoma↗

Environmental factors related to Epstein-Barr virus-associated gastric cancer in Japan.

Epstein-Barr virus (EBV)-encoded small RNA can be detected in about 1-17% of gastric carcinomas. To elucidate the lifestyles and other factors related to the EBV-associated gastric carcinoma (EBV-GC), we interviewed 43 EBV-GC cases and 162 non EBV-GC cases in Kagoshima Prefecture, Japan from 1996-2001. We mainly focused on lifestyles predominant among men because of its male predominance. Although the prevalence of smokers in EBV-GC cases was higher than among non EBV-GC cases, the difference was not significant (P = 0.131). Frequent drinking of coffee and high-temperature drinks, as well as frequent intake of salty and spicy foods, were more prevalent among EBV-GC cases, but only frequent intake of salty food showed a significant difference between EBV-GC and non EBV-GC cases (P = 0.026). In addition, EBV-GC cases tended to be exposed to wood dust and/or iron filings (P = 0.068) and tar (P = 0.097). These findings, together with a high frequency of EBV-GC among remnant cancers after partial gastrectomy, suggest an association between mechanical injuries to the stomach membrane and the high frequency of EBV-GC. The present study also showed that EBV-GC cases tended to be elder brothers/sisters (P for trend = 0.029) suggesting that age at primary infection with EBV may be older in EBV-GC cases than non EBV-GC cases.

Age Factors↗

Body mass index, serum sex hormones, and breast cancer risk in postmenopausal women.

BACKGROUND: Obesity is associated with increased breast cancer risk among postmenopausal women. We examined whether this association could be explained by the relationship of body mass index (BMI) with serum sex hormone concentrations. METHODS: We analyzed individual data from eight prospective studies of postmenopausal women. Data on BMI and prediagnostic estradiol levels were available for 624 case subjects and 1669 control subjects; data on the other sex hormones were available for fewer subjects. The relative risks (RRs) with 95% confidence intervals (CIs) of breast cancer associated with increasing BMI were estimated by conditional logistic regression on case-control sets, matched within each study for age and recruitment date, and adjusted for parity. All statistical tests were two-sided. RESULTS: Breast cancer risk increased with increasing BMI (P(trend) =.002), and this increase in RR was substantially reduced by adjustment for serum estrogen concentrations. Adjusting for free estradiol reduced the RR for breast cancer associated with a 5 kg/m2 increase in BMI from 1.19 (95% CI = 1.05 to 1.34) to 1.02 (95% CI = 0.89 to 1.17). The increased risk was also substantially reduced after adjusting for other estrogens (total estradiol, non-sex hormone-binding globulin-bound estradiol, estrone, and estrone sulfate), and moderately reduced after adjusting for sex hormone-binding globulin, whereas adjustment for the androgens (androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone) had little effect on the excess risk. CONCLUSION: The results are compatible with the hypothesis that the increase in breast cancer risk with increasing BMI among postmenopausal women is largely the result of the associated increase in estrogens, particularly bioavailable estradiol.

Aged↗

Ceramide accelerates dephosphorylation of extracellular signal-regulated kinase 1/2 to decrease prostaglandin D(2) production in RBL-2H3 cells.

In the present study, the effect of ceramide on antigen-stimulated phosphorylation of extracellular signal-regulated kinase (ERK) in the mechanism responsible for regulating production of prostaglandin (PG) D(2) was investigated in the mast cell line, RBL-2H3 cells. Cell-permeable C(6)-ceramide (N-hexanoylsphingosine) suppressed antigen-stimulated phosphorylation of ERK1/2 and p38 mitogen-activated protein kinase. Ceramide also inhibited production of PGD(2) and an increase in the activity of cytosolic phospholipase A(2) (cPLA(2)), whereas it did not influence the tyrosine phosphorylation of major cellular proteins in response to antigen. The ceramide-induced inhibition of ERK1/2 phosphorylation and of cPLA(2) activation was suppressed by orthovanadate, a tyrosine phosphatase inhibitor, but not by okadaic acid, a serine/threonine phosphatase inhibitor. Addition of ceramide to the lysate prepared from antigen-stimulated cells reduced the phosphorylated ERK1/2, and orthovanadate effectively prevented the reduction. These results suggest that ceramide accelerates the dephosphorylation of phosphorylated ERK1/2 via activation of a protein tyrosine phosphatase, thus preventing activation of cPLA(2) and production of PGD(2).

Animals↗

Expression of functional lung resistance--related protein predicts poor outcome in adult T-cell leukemia.

Chemotherapy of patients with adult T-cell leukemia (ATL) has been unsuccessful. The poor outcome is thought to be caused mainly by the drug resistance of ATL cells. Lung resistance-related protein (LRP) is a novel protein associated with drug resistance. The expression of LRP messenger RNA (mRNA) was evaluated by slot blot analysis in 55 patients with ATL. Of these patients, 36 had acute, 12 chronic, and 7 lymphoma-type ATL. The expression levels of LRP mRNA were significantly higher in chronic ATL than in lymphoma-type ATL (P =.007). The expression of LRP mRNA was higher in patients with white blood cell counts above 30,000/microL (P =.038) or with abnormal lymphocyte counts above 10,000/microL (P =.007) than in the remaining patients. The enhanced efflux of [(14)C]doxorubicin from nuclei isolated from ATL cells that expressed high levels of LRP was inhibited by a polyclonal antibody against LRP, and the accumulation of doxorubicin in the isolated nuclei was increased by the anti-LRP antibody. In acute and lymphoma-type ATL patients, high expression of LRP mRNA at diagnosis correlated with shorter survival, and a Cox proportional hazards model showed that LRP expression is an independent prognostic factor. These findings suggest that functionally active LRP is expressed in some ATL cells and that it is involved in drug resistance and poor prognosis in ATL. (Blood. 2001;98:1160-1165)

Active Transport, Cell Nucleus↗

Relation between cyclooxygenase-2 expression and tumor invasiveness and patient survival in transitional cell carcinoma of the urinary bladder.

BACKGROUND: Expression of the inducible form of cyclooxygenase (COX)-2 is known to correlate with development of transitional cell carcinoma (TCC) of the human urinary bladder. However, the clinical significance of COX-2 expression with respect to clinicopathologic findings and patient survival is unknown. METHODS: COX-2 expression was examined immunohistochemically in tumor tissues obtained from 108 patients who underwent radical cystectomy for TCCs, without knowledge of clinicopathologic findings. Correlation between COX-2 expression and clinicopathologic findings and patient survival was determined. RESULTS: COX-2 expression was detected in 34 of 108 (31%) tumors but in none of 10 normal uroepithelial samples. Univariate logistic regression analysis showed a significant correlation between COX-2 expression and local invasion, infiltration pattern, lymphatic invasion, and venous invasion. However, multivariate logistic regression analysis revealed that only local invasion correlated significantly with COX-2 expression (P = 0.047). Cox proportional hazards regression analysis showed that both local invasion (P = 0.008) and lymph node metastasis (P = 0.001) were independent prognostic factors; however, COX-2 expression (P = 0.16) was not. CONCLUSIONS: The authors showed that COX-2 overexpression plays a role in development and invasion of TCCs, but not prognosis of patients with TCC. COX-2 inhibitors may be useful for chemoprevention of TCCs and treatment of invasive disease.

Adult↗

Secretory phospholipase A2 mediates cooperative prostaglandin generation by growth factor and cytokine independently of preceding cytosolic phospholipase A2 expression in rat gastric epithelial cells.

Transforming growth factor (TGF)-alpha and interleukin (IL)-1beta are responsible for the healing of gastric lesions through, in part, prostaglandin (PG) generation. We examined the contribution of cytosolic and secretory phospholipase A(2)s (cPLA(2) and sPLA(2)) to the PG generation by rat gastric epithelial cells in response to both stimuli. Stimulation with TGF-alpha for 24 h increased cPLA(2) and cyclooxygenase (COX)-2 markedly, PGE(2) slightly, and type IIA sPLA(2) and COX-1 not at all, whereas IL-1beta increased sPLA(2) only. Both stimuli synergistically increased PGE(2), sPLA(2), and the two COXs but not cPLA(2). The onset of the PGE(2) generation paralleled the sPLA(2) release but was apparently preceded by increases in cPLA(2) and the two COXs. The increase in PGE(2) was impaired by inhibitors for sPLA(2) and COX-2 but not COX-1. cPLA(2) inhibitors suppressed PGE(2) generation by TGF-alpha alone but not augmentation of PGE(2) generation or sPLA(2) release by IL-1beta in combination with TGF-alpha. Furthermore, despite an increase in cPLA(2) including its phosphorylated form (phosphoserine), -induced arachidonic acid liberation was impaired in the TGF-alpha/IL-1beta-stimulated cells, in which p11, a putative cPLA(2) inhibitory molecule, was also increased and co-immunoprecipitated with cPLA(2). These results suggest that synergistic stimulation of sPLA(2) and COX-2 expression by TGF-alpha and IL-1beta results in an increase in PGE(2). Presumably, the preceding cPLA(2) expression is not involved in the PGE(2) generation, because of impairment of its hydrolytic activity in the stimulated cells.

Animals↗

Epstein-Barr virus in gastric carcinoma is associated with location in the cardia and with a diffuse histology: a study in one area of Chile.

Epstein-Barr virus (EBV) has been associated with the most common form of stomach neoplasms, the gastric carcinoma (GC). The presence of EBV-encoded small RNAtype-1 (EBER-1), a marker for EBV infection was analyzed by in situ hybridization (ISH) in 185 formalin-fixed and paraffin-embedded cases of GC from a high risk region. We found 31 (16.8%) EBV-positive cases with no relationship to age. Although male predominance (19% in males and 12.5% in females) was observed, the gender difference did not achieve statistical significance. Odds ratio (OR) for cardia location was 5.4 (95% CI 1.7-17.3) when antrum was used as referent category and the effects of gender and age were taken into account. The proportion of EBV-positive cases in diffuse histology was higher than intestinal type (OR = 4.8, 95% CI = 2.0-11.1). Our findings are contrary to a previously accepted hypothesis, that high-risk countries for GC have low rates of EBV-associated GC. In addition, our findings regarding location, histology and weak male predominance are different from what has been described in Asian and European countries, but similar to those described in Mexico and Mexican descendants living in the U.S. suggesting unique characteristics of EBV-associated GC in Latin-America.

Adult↗

Preoperative assessment of vascularity by color Doppler ultrasonography in human rectal carcinoma.

PURPOSE: Although angiogenesis assessed by immunostaining endothelial cells (microvessel density) is a well-known prognostic factor in a wide variety of human solid tumors, preoperative determination of microvessel density seems to be difficult in rectal carcinoma. Thus, we performed transanal color Doppler ultrasonography in 46 patients with rectal carcinoma to assess preoperative angiogenic status and compare it with microvessel density in surgical specimens. METHODS: Time-averaged maximal velocity, peak systolic velocity, number of vascular points, and vascular point index were conducted by color Doppler ultrasonography in 46 patients with rectal carcinoma. Number of vascular points was defined as the number of vessels with pulsation in the section of tumor. Vascular point index was defined as the average number of vascular points divided by the area assessed by color Doppler ultrasonography in the section of tumor. The profiles of number of vascular points were similar to those assessed by microangiography in five rectal carcinomas. RESULTS: Vascular point index significantly correlated with microvessel density (P < 0.0001). No significant correlation was found between microvessel density and time-averaged maximal velocity or peak systolic velocity. Vascular point index was also a better indicator of lymph node metastasis and venous invasion than microvessel density. In addition, 11 of 46 cases with postoperative hematogenous metastasis (23.9 percent) were observed prospectively. Vascular point index may be a best predictor for hematogenous metastasis from rectal carcinoma compared with peak systolic velocity, time-averaged maximal velocity, and microvessel density by receiver operating characteristic analysis. CONCLUSION: These results suggest that preoperative quantification of angiogenesis using color Doppler ultrasonography will provide quick and useful information in the management of rectal carcinoma.

Blood Flow Velocity↗

Quantitative evaluation of skin condition in an epidemiological survey of females living in northern versus southern Japan.

Image analysis and biophysical methods were used to compare the skin condition of a group of females ranging in age from 5 to 65 years who had lived all of their lives in either Kagoshima (n=300), located in southern Japan, or Akita (n=302), located in northern Japan. Kagoshima annually receives approximately 1.5 times more solar UVB radiation than Akita. The methods used and corresponding skin parameters reported in this survey were: high resolution digital imaging followed by computer analysis of facial images for facial skin wrinkling and hyperpigmentation; silicone skin replicas followed by Moiré interferometry for facial skin surface roughness (texture); the Minolta Chromameter for skin color (L*a*b*) on sun-exposed (forehead) and sun-protected (upper inner arm) skin sites; the Corneometer for skin capacitance (hydration) on the cheek and ventral forearm; the Sebumeter for sebum excretion rate on the forehead; and the Minolta Spot Thermometer for skin temperature on the upper cheek. Compared with Japanese women living in Akita, Japanese women living in Kagoshima had significantly longer facial wrinkles, higher number of wrinkles, larger hyperpigmented spots, higher number of spots, rougher facial skin texture, more yellow foreheads and upper inner arms, darker foreheads, and less stratum corneum hydration in the cheeks and arms. When compared on an age-for-age basis, the average 40-year-old Kagoshima women has the same level of facial wrinkling as a 48-year-old Akita women, a delay of 8 years for living in the northern latitude. For facial hyperpigmentation, the delay is 16 years; the average 40-year-old Kagoshima women has the same level of facial hyperpigmentation as a 56-year-old Akita women. The results further testify to the skin damaging effects of sun exposure and may be useful in public health education to promote everyday sun protection.

Adolescent↗

Patterns of pelvic invasion are prognostic in the treatment of locally recurrent rectal cancer.

BACKGROUND: Local recurrence of rectal cancer after curative resection remains a difficult clinical problem. The aim of this study was to elucidate prognostic risk factors after resection of recurrent cancer. METHODS: Between January 1983 and December 1999, 83 patients with locally recurrent rectal cancer were studied retrospectively for survival benefit by re-resection. Sixty patients underwent resection for recurrent cancer, including total pelvic exenteration in 30 patients and sacrectomy in 23 patients. The extent of locally recurrent tumour was classified by the pattern of pelvic invasion as follows: localized, sacral invasion and lateral invasion. RESULTS: Multivariate analysis showed that the pattern of pelvic invasion was a significant prognostic factor which independently influenced survival after resection of recurrent cancer (P < 0.001). The 5-year survival rates were 38 per cent in the localized type (n = 27), 10 per cent in the sacral invasive type (n = 16) and zero in the lateral invasive type (n = 17). CONCLUSION: Resection for locally recurrent rectal cancer is potentially curative in patients with localized or sacral invasive patterns of recurrence. Alternatives should be explored in patients with recurrence involving the lateral pelvic wall.

Adult↗

HTLV-I proviral load correlates with progression of motor disability in HAM/TSP: analysis of 239 HAM/TSP patients including 64 patients followed up for 10 years.

To clarify clinical and laboratory findings that may be related to the pathomechanism of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we analyzed these findings in 239 patients with HAM/TSP, including 64 patients followed up for 10 years after their first examinations, with special interest in the HTLV-I proviral load in peripheral blood mononuclear cells (PBMCs). The proviral load in PBMCs did not differ in terms of modes of HTLV-I transmission. However, the proviral load in patients with age of disease onset greater than 65 years tended to be higher than those with a younger age of onset. In the 64 patients followed up for 10 years, the clinical symptoms deteriorated in 36 patients (56%), unchanged in 26 patients (41%), and improved in 2 patients (3%). HTLV-I proviral load also appeared to be related to the deterioration of motor disability in these patients. To our knowledge, the present study is the first longitudinal study concerning the relationship between the clinical course of HAM/TSP and HTLV-I proviral load. It is suggested that HTLV-I proviral load is related to the progression of motor disability and is an important factor to predict prognosis of patients with HAM/TSP.

Age of Onset↗

Epstein-Barr virus-associated gastric carcinoma in Japanese Brazilians and non-Japanese Brazilians in São Paulo.

The proportion of Epstein-Barr virus-associated gastric carcinoma (EBV-GC) was examined in 149 Japanese-Brazilian and 151 non-Japanese-Brazilian gastric-carcinoma cases using in situ hybridization (ISH) assay to detect EBV-encoded small RNA (EBER), and the results were compared with our referent Japanese data. We found that 4.7% of cases in Japanese Brazilians were EBER-positive. This frequency was slightly lower than that of the referent Japanese, among whom 6.2% of 2038 gastric-carcinoma cases were EBER-positive. On the other hand, the non-Japanese-Brazilian series showed a significantly higher proportion of EBV-GC (11.2%) than the referent group did (P = 0.01). Although EBV-GC was predominant in males among non-Japanese Brazilians (M / F = 3.6, P = 0.047), as was the case in Japanese (M / F = 2.7), Japanese Brazilians did not show such a male predominance. The sex-ratio difference between the Japanese Brazilians and Japanese was statistically significant (P = 0.005). In conclusion, the present study in Japanese Brazilians and Japanese yielded no evidence suggesting any change in the frequency of EBV-GC caused by migration, except the absence of male predominance, which was observed both in Japanese and non-Japanese Brazilians.

Adenocarcinoma↗

Cloning of a gene encoding a highly stable endo-beta-1,4-glucanase from Aspergillus niger and its expression in yeast.

A gene encoding an endo-beta-1,4-glucanase, which is highly resistant to high temperature, protease and surfactant treatment, was isolated from Aspergillus niger IFO31125 and designated as eng1. The deduced amino acid sequence encoded by eng1 showed high homology with the sequence of a not-well-characterized cellulase encoded by eglB which has not yet been shown to be a stable enzyme. To confirm the sequence of the gene encoding the highly stable endo-beta-1,4-glucanase, the cloned gene was expressed in the yeast Saccharomyces cerevisiae, in which no cellulase activity was found, and the gene product was purified and subjected to enzymatic characterization. The enzyme retained 56% of the initial activity after 1 h of incubation at 80 degrees C and was stable in the range of pH 3.0-10.0. The optimal temperature for enzyme activity was 70 degrees C and the optimal pH was 6.0. The enzyme was highly protease-resistant and retained more than 80% of the initial activity after protease treatment for 3 d at 40 degrees C. The enzyme was also resistant to various surfactants. From these results, eng1 was confirmed to encode a very stable endo-beta-1,4-glucanase.

Journal Article↗