PubMed Health⌕ Search

Biomedical subjects

R Shimada

Publications and source records attributed to R Shimada.

At least 19 recordsLinked to original sources
PubMed2006

Cloning, functional expression and promoter analysis of xylanase III gene from Trichoderma reesei.

In this study, the xyn3 gene from the filamentous mesophilic fungus Trichoderma reesei (Hypocrea jecorina) PC-3-7 was cloned and sequenced. Analysis of the deduced amino acid sequence of XYN III revealed considerable homology with xylanases belonging to glycoside hydrolase family 10. These results show that XYN III is distinguishable from XYN I and XYN II, two other T. reesei xylanases that belong to the glycosidase family 11. When xyn3 was expressed in Escherichia coli, significant activity was observed in the cell-free extract, and higher activity (13.2 U/ml medium) was recovered from the inclusion bodies in the cell debris. The sequence of the 5'-upstream region of the gene in the parent strain QM9414 is identical to that of PC-3-7, although the expression level of xyn3 in PC-3-7 has been reported to be at least 1,000 times greater than in QM9414. These results suggest that xyn3 expression in T. reesei QM9414 is silenced. The consensus sequences for ACEI, ACEII, CREI, and the Hap2/3/5 protein complex are all present in the upstream region of xyn3. Deletion analysis of the upstream region revealed that two regions containing consensus sequences for the known regulatory elements play important roles for xyn3 expression.

Amino Acid Sequence↗
PubMed2001

A study of factors influencing prognosis after resection of hepatic metastases from colorectal and gastric carcinoma.

OBJECTIVE: The aim of this study is to determine the absolute contraindication for hepatic resection for colorectal metastases and investigate the value of hepatectomy for gastric metastases by comparing it with the results of colorectal metastases performed with the same criteria. METHODS: A retrospective cohort study was conducted in patients undergoing hepatic resection for metastatic colorectal (n = 64) and gastric (n = 17) carcinomas. Common predictive factors for both metastases were analyzed by the stratified Cox proportional hazard model. In this model, the different baseline hazard was set for each disease, whereas the risk of each covariate was assumed to be equal in both gastric and colorectal metastases. RESULTS: Overall 1-, 2-, and 5-yr survival rates after hepatectomy for colorectal and gastric metastases were 90%, 73%, 42%, and 47%, 22%, 0%, respectively. Factors controlling prognosis were as follows: age > or = 60, extrahepatic metastases, serosal invasion, grade of lymph node metastases, tumor cell differentiation of the primary lesion(s), carcinoembryonic antigen level, tumor-exposed surgical margin, and blood transfusion. In particular, presence of extrahepatic metastases showed the markedly high-risk ratio among these eight variables. CONCLUSIONS: Hepatectomy, if possible, is indicated in patients with hepatic metastases from colorectal carcinoma if there are no extrahepatic metastases and if the primary disease is controlled. It is indicated only in carefully selected patients with metastases from gastric carcinoma.

Adult↗
PubMed2001

Denaturing gradient gel electrophoresis analyses of microbial community from field-scale composter.

The diversity of microbial community during the decomposition of waste in a field-scale composter (Hazaka system) was investigated by denaturing gradient gel electrophoresis (DGGE). The composter operates at a high temperature through a self-heating system, creating a thermophilic (60-76 degrees C) stage during the initial phase and a mesophilic (45 degrees C) stage towards the later phase of the composting period. The pH of the system (pH 7.75-8.10) did not vary significantly during the process while moisture content was reduced from 48.8% to 25.1%. DGGE and 16S rDNA analyses showed that the following genera were found throughout the process: Propionibacterium sp., Methylobacterium sp., Pseudomonas sp., and Bradyrhizobium sp. Different Bacillus spp. thrive at the thermophilic or the mesophilic stage while Clostridium sp. was only found at the initial phase of the process. Staphylococcus sp. and Caulobacter sp. or Brevundimonas sp. existed during the later phase of the composting period.

Journal Article↗
PubMed2000

Suppression of azoxymethane-induced colon carcinogenesis in male F344 rats by mandarin juices rich in beta-cryptoxanthin and hesperidin.

We have reported protective effects of dietary administration of a powder "CHRP" containing high amounts of beta-cryptoxanthin and hesperidin prepared from a Satsuma mandarin (Citrus unshiu Marc.) juice on azoxymethane (AOM)-induced rat aberrant crypt foci through suppression of crypt cell proliferation and/or induction of detoxifying enzymes. In the present study, we investigated the modifying effects of a commercial Satsuma mandarin (Citrus unshiu Marc.) juice (MJ) and those of MJ2 and MJ5, which were prepared from MJ and are richer in beta-cryptoxanthin and hesperidin than MJ, on the occurrence of colonic tumors induced by AOM in male F344 rats. Rats were given 2 weekly s.c. injections of AOM (20 mg/kg body weight) to induce colonic neoplasms. They also received MJ, MJ2, or MJ5 as a drinking water at night for 36 weeks, starting 1 week after the last dosing of AOM. AOM exposure produced colonic adenocarcinoma with an incidence of 69% and a multiplicity of 0.76 +/- 0.57/rat at week 38. MJ, MJ2, and MJ5 administration significantly reduced the frequency of colonic carcinoma [MJ: 35% (49% reduction), p < 0.02; MJ2: 20% (64% reduction), p = 0.0028; and MJ5: 15% (78% reduction), p < 0.00021] and multiplicity [MJ: 0.40 +/- 0.58 (47% reduction), p < 0.05; MJ2: 0.25 +/- 0.43 (67% reduction), p < 0.005; and MJ5: 0.15 +/- 0.36 (80% reduction), p < 0.001]. Also, the numbers of cancer cells positive for proliferative cell nuclear antigen (PCNA) and cyclin D1 in colonic tumors were lowered by these treatments. In addition, treatment with MJ, MJ2, or MJ5 significantly increased apoptotic index in colonic adenocarcinoma. These findings might suggest effective chemopreventive ability of MJs, especially MJ5, in colon tumorigenesis.

Adenocarcinoma↗
PubMed2000

Aggressive surgical approach to recurrent tumors after hepatectomy for metastatic spread of colorectal cancer to the liver.

BACKGROUND: Liver resection is currently accepted as the only potential cure for patients with metastases of colorectal tumors in the liver. However, cancer will recur in more than 70% of patients. METHODS: In the 7 years to December 1997, 60 patients underwent liver resections for colorectal metastases at our institute. Of these, 20 patients had repeated surgical resections for recurrent disease of the liver and other organs. Another 2 patients had undergone previous hepatectomy elsewhere. The clinical data for these patients were reviewed. RESULTS: The median interval between the 2 resections was 16 months. Eighteen hepatectomies, 6 lung resections, and 1 pancreatoduodenectomy were performed in 22 patients. Operative mortality and complication rates were 0% and 18%, respectively. At a median follow-up of 25 months after repeated resection, the survival rate in these patients was 73% at 2 years (12 of 16 evaluable patients are surviving) and 22% at 5 years (2 of 10 evaluable patients are surviving); the median survival time was 44 months. CONCLUSIONS: Repeated resections for recurrent colorectal metastases yield comparable results to first liver resections in operative mortality and morbidity rates, survival time, and pattern of recurrence. Although the number of patients surviving more than 5 years is still limited, the absence of other proven treatments supports the concept of an aggressive resectional approach for these patients.

Adult↗
PubMed2000

Prevention of colonic aberrant crypt foci by dietary feeding of garcinol in male F344 rats.

The modifying effects of dietary feeding of a polyisoprenylated benzophenone, garcinol, isolated from Garcinia indica fruit rind on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. We also assessed the effects of garcinol on proliferating cell nuclear antigen (PCNA) index in ACF and activities of detoxifying enzymes of glutathione S-transferase (GST) and quinone reductase (QR) in liver. In addition, we examined the effects of garcinol on 12-O-tetradecanoylphorbol-13-acetate-induced O(2)(-) generation in differentiated human promyelocytic HL-60 cells and lipopolysaccharide (LPS)- and interferon (IFN)-gamma-induced nitric oxide (NO) generation in mouse macrophage RAW 264.7 cells. Western blotting analysis of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression was done in LPS- and IFN-gamma-treated mouse macrophage RAW 264.7 cells. Rats were given subcutaneous injections of AOM (15 mg/kg body wt) once a week for 3 weeks to induce ACF. They also received the experimental diet containing 0.01 or 0.05% garcinol for 5 weeks, starting 1 week before the first dosing of AOM. AOM exposure produced 97 +/- 15 ACF/rat at the end of the study (week 5). Dietary administration of garcinol caused significant reduction in the frequency of ACF: 72 +/- 15 (26% reduction, P < 0.01) at a dose of 0.01% and 58 +/- 8 (40% reduction, P < 0.001) at a dose of 0.05%. Garcinol administration significantly lowered PCNA index in ACF. Feeding of garcinol significantly elevated liver GST and QR activities. In addition, garcinol could suppress O(2)(-) and NO generation and expression of iNOS and COX-2 proteins. These findings might suggest possible chemopreventive ability of garcinol, through induction of liver GST and QR, inhibition of O(2)(-) and NO generation and/or suppression of iNOS and COX-2 expression, on colon tumorigenesis.

Animals↗
PubMed1999

Bone marrow pre-B-1 (Bomb1): a quantitative trait locus inducing bone marrow pre-B-cell expansion in lymphoma-prone SL/Kh mice.

Abnormalities of regulatory genes in early B-cell development often lead to lymphomagenesis. Our previous study showed that there is an abnormal transient expansion of bone marrow (BM) pre-B cells in lymphoma-prone SL/Kh strain mice. Such expansion is a genetic property of SL/Kh stem cells rather than BM microenvironments. Using the percentage of BP1+ B220+ pre-B cells in total BM lymphoid cells as a quantitative parameter, we studied the genetic control of BM pre-B cells in 159 F2 offspring of crosses between SL/Kh and NFS/N mice and 334 back-crosses to SL/Kh mice. A highly significant quantitative trait locus was identified on the distal segment of chromosome 3, showing logarithm of odds scores of 22.7 in the F2 cohort and 10.7 in back-cross mice. This quantitative trait locus, named bone marrow pre-B-1, colocalized with lymphoid enhancer factor-1, which encodes a high mobility group DNA-binding protein that is expressed in T and pre-B cells.

Animals↗
PubMed1999

Preoperative portal vein embolization: an audit of 84 patients.

Preoperative portal vein embolization (PVE) was performed in 84 patients before extensive liver resection for various diseases. By the criteria of liver volumetric determination, some patients were candidates for PVE, whereas others were not, even though the same surgical procedure, such as extended right lobectomy (ERL), was scheduled. PVE using gelatin sponge powder induced hypertrophy in the nonembolized lobe (0%-171%; median, 30%) and proportional atrophy in the embolized lobe in 2 weeks without eliciting any major inflammatory or necrotic reaction, as evidenced histologically and by the minimal elevations in the serum aspartate transaminase (AST) and alanine transaminase (ALT) values. Alterations in the total bilirubin level and prothrombin time were also insignificant and transient, indicating that hepatocyte functions were not impaired by PVE. Not all patients who undergo PVE proceed with the scheduled hepatic resection procedure, so it is a great advantage that gelatin sponge causes minimal damage compared with other embolizing materials such as cyanoacrylate and absolute ethanol, which have been reported to induce an inflammatory reaction or histological alteration. Our multiple regression analysis showed that three factors, diabetes mellitus, a high total bilirubin level at the time of PVE, and being male, each reduced the extent of hypertrophy in the nonembolized lobe (r2 =.30). By contrast, cholestasis appeared to accelerate the process of atrophy in the embolized lobe (r2 =.16). In conclusion, PVE by gelatin sponge powder is a safe and effective preoperative maneuver that induces hypertrophy of the section of the liver that will remain after partial hepatectomy.

Adult↗
PubMed1999

Prognostic significance of anatomical resection and des-gamma-carboxy prothrombin in patients with hepatocellular carcinoma.

BACKGROUND: Portal venous tumour extension and intrahepatic metastasis result in a poor prognosis following hepatectomy for hepatocellular carcinoma (HCC). Anatomical resection is, in theory, preferable for eradicating these types of invasion. Des-gamma-carboxy prothrombin (DCP) has been reported to be associated with adverse pathological variables. This study investigated the significance of anatomical resection and DCP as predictive factors for postoperative recurrence of HCC. METHODS: A retrospective cohort study was carried out in 138 consecutive patients who underwent hepatectomy for HCC smaller than 5 cm using the Cox proportional hazards model. RESULTS: Eight factors were univariately related to poor prognosis (in decreasing order of hazard ratio): intrahepatic metastasis, multiple tumours, alpha-fetoprotein 32 ng/ml or more; DCP greater than 0.1 arbitrary units (AU), tumour-exposed surgical margin, vascular invasion, non-anatomical resection and tumour 2.5 cm or more. Three variables (DCP, vascular invasion and tumour-exposed surgical margin) were excluded by a stepwise procedure in multivariate analysis. Although DCP was not an independent prognostic factor, a model replacing intrahepatic metastasis with DCP showed similar predictive accuracy in a receiver-operating characteristic curve. CONCLUSION: Anatomical resection appeared to have a beneficial effect on recurrence-free survival after hepatectomy for HCC. DCP measurement was effective in predicting HCC recurrence and had the advantage that it can be assessed before operation.

Biomarkers↗
PubMed1999

Proximal bile duct stricture disguised as malignant neoplasm.

BACKGROUND: Discrimination of malignant proximal bile duct (PBD) stricture from a benign lesion is difficult with nonsurgical methods; indeed, 8% to 13% of PBD strictures prove to be benign after histologic examination of the surgically resected specimen. METHODS: In a 7-year period 178 patients with PBD stricture were admitted, and 99 of them underwent radical resection for presumably malignant lesions. In 14 of these patients the stenotic lesions were proved to be benign by postoperative histologic assessment. We reviewed these patients retrospectively by collecting data from their charts. RESULTS: Preoperative radiologic findings including cholangiography and angiography were compatible with malignancy in all 14 patients. Preoperative histologic studies suggested malignancy in 2 of 8 examined. Findings at laparotomy could not allow differentiation between malignant and benign lesions in any of the patients and strongly suggested malignancy in 3. Histologic examination of the resected specimens revealed extensive fibrosis with inflammatory cellular infiltration in all patients. There was 1 episode of significant morbidity postoperatively (transient cholangitis) but no mortality. CONCLUSION: Benign PBD strictures, although rare, are usually indistinguishable from malignant PBD strictures by preoperative or perioperative investigation. Given the minimal morbidity, all PBD strictures should be presumed malignant and managed accordingly, even at the risk of overtreating some benign cases.

Aged↗
PubMed1998

Relationship between doubling time of liver metastases from colorectal carcinoma and residual primary cancer.

BACKGROUND: The doubling times of liver metastases were calculated in order to clarify their usefulness in predicting the presence of residual cancer in the abdominal cavity in patients who had undergone curative resection of primary colorectal cancer. PATIENTS AND METHODS: Tumor doubling times were calculated retrospectively in 22 patients by serial measurement of the size of their liver metastases. RESULTS: Patients with a tumor doubling time of less than 92.4 days had a significantly poorer prognosis than those with a doubling time more than or equal to 92.4 days (p < 0.05). Local recurrence or peritoneal dissemination was significantly more likely to occur when the tumor doubling time was less than 92.4 days than when it was more than or equal to 92.4 days (p < 0.01). CONCLUSION: The doubling time of hepatic metastases in patients with colorectal carcinoma may be a useful prognostic indicator, with patients who have a shorter tumor doubling time carrying a greater risk of residual primary cancer in the abdominal cavity.

Cell Division↗
PubMed1998

Staged hepatectomy after emergency transcatheter arterial embolization for ruptured hepatocellular carcinoma.

BACKGROUND: Staged hepatectomy after emergency transcatheter arterial embolization (TAE) has been advocated in ruptured hepatocellular carcinoma (HCC). However, there have been no reports of clinical series of this strategy. The purpose of this study was to evaluate the protocol of this therapeutic strategy. METHODS: Sixteen patients with suspected rupture of HCC were included in the study. After emergency TAE, tumor resectability was assessed, followed by staged hepatectomy or repeated TAE. The patients were reevaluated with regard to rupture of HCCs. RESULTS: Primary hemostasis was achieved successfully in all patients. Eleven patients were finally judged to have experienced HCC rupture. Seven of them underwent staged hepatectomy; the other four underwent repeated TAE because their tumors were considered unresectable. Survival time tended to be longer, but not to a significant extent, in patients who underwent hepatectomy (range, 139 to 1527 days; median, 375 days) than in those treated by TAE alone (range, 43 to 1317 days; median, 158 days). CONCLUSIONS: Staged hepatectomy after TAE is a rational treatment for patients with ruptured HCC. Although TAE is highly effective for initial hemostasis, hepatectomy appears to provide better long-term survival.

Adult↗
PubMed1997

The structure and organization of the human NPAT gene.

Ataxia telangiectasia (AT) is an autosomal recessive gene disorder, and ATM, a housekeeping gene, has been identified as the gene responsible for AT. Recently we found that another housekeeping gene, NPAT, is located upstream of ATM on human chromosome 11. The two housekeeping genes are transcribed in opposite directions and share a 0.5-kb 5' flanking sequence. The structure and organization of NPAT were determined by direct sequencing of cosmid clones carrying the gene and by application of the long and accurate (LA)-PCR method to amplify regions encompassing the exon/intron boundaries and all of the exons. The gene spans at least 44 kb and consists of 18 exons and 17 introns. It has been suggested that AT heterozygotes have an increased risk of developing cancer, especially breast cancer in women. Frequently, loss of heterozygosity at loci on 11q22-q24 has been observed in DNA isolated from tumors of the breast, uterine cervix, and colon, perhaps suggesting the location of a tumor suppressor gene in 11q22-q24. For investigation of the role of NPAT in AT and these tumors with allelic loss of 11q22-q24, appropriate primer sequences and PCR conditions for amplification of all the NPAT exons from genomic DNA were determined. We previously reported that no recombinations are found among Atm, Npat, and Acat1 (acetoacetyl-CoA thiolase) loci as determined by fine genetic linkage mapping of the mouse AT region. The results of the LA-PCR analysis using NPAT- and ACAT-specific primers and human genomic DNA allowed us to map ACAT 12 kb centromeric to NPAT.

Animals↗
PubMed1997

Plasma concentration of endothelin-1 does not reflect renal vasoconstriction as estimated by duplex ultrasonography in cirrhosis.

Endothelin, a potent vasoconstrictor, is thought to play a role in liver cirrhosis-related functional kidney failure. Our aim was to investigate the correlation between renal vasoconstriction, as detected by a Doppler ultrasound technique, and plasma concentrations of endothelin in cirrhotic patients. Fifty cirrhotic patients underwent Doppler examinations to detect renal vasoconstriction. The plasma concentration of endothelin was measured in 10 patients who exhibited vasoconstriction of the renal microvessels diagnosed by Doppler waveform analysis and was compared to that of patients in whom there was no sign of such vasoconstriction. No difference was observed in the plasma concentration of endothelin between patients in whom renal vasoconstriction was diagnosed and those in whom it was not. Our results suggested that the circulating endothelin does not reflect renal vasoconstriction, at least in the early phase of the functional renal failure associated with cirrhosis of the liver.

Endothelin-1↗
PubMed1989

[In vitro hemodynamic characteristics of prosthetic heart valves].

The functional characteristics of the prosthetic heart valve are the hemodynamic characteristics when it has been ideally attached; in clinical practice, however, it is seldom that this artificial valve is ideally put in position because of the modality of changeable valve angle in deformed annulus and the narrow aortic root, orientation of the valve, anatomical factors, etc. Thus, we devised an attachment head for the prosthetic valve whose angle can freely be varied in order to evaluate the hemodynamic characteristics of five clinically-available mechanical prosthetic valves and two xenografts in the pulsatile circulation system in the mitral position by changing the angle and orientation of the valve attachment. The prosthetic valves used were St Jude Medical (SJM), Starr-Edwards ball (S-E), monostrut Björk-Shiley (mB-S), Omniscience (OS), Omnicarbon (OC), Carpentier-Edwards Supra-annular (C-Es) and Carpentier Edwards Pericardial (C-Ep) whose tissue annulus diameter was 27 mm. The experimental instrument similar to that of Umezu et al. was prepared to determine the mean pressure gradient, output and calculated orifice area of each valve. At the same time, a recently-manufactured valve attachment head was employed to measure the output, pressure gradient and orifice area by altering the valve attachment angle and orientation and increasing the number of heart beats from 60 bpm to 160 bpm, and the following results were obtained: With the changeable angle valve, an angle was determined whose end was parallel to the flow path in association with changes in the attachment angle, and the orientation was such that the pressure gradient was reduced and the orifice area was increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioprosthesis↗