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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 127 records · Page 7Linked to original sources
PubMed2001

Enzymatic characterization and interspecies difference of phenol sulfotransferases, ST1A forms.

Cytosolic sulfotransferases, which mediate activation and detoxification of both endogenous and exogenous compounds, consist of at least five different gene families (ST1 to ST5) in mammals. Several cDNAs corresponding to ST1A forms have been reported, but their functional properties are not well characterized. In addition, only a single form of ST1A sulfotransferase has been reported in each experimental animal species despite the expressions of plural forms in humans. Therefore, enzymatic properties of human ST1A3, ST1A5, rat ST1A1, mouse St1a4, and newly isolated rabbit ST1A8 have been characterized and compared by use of their recombinant proteins to clarify the functional difference between human and experimental animal ST1A forms. From the results using more than 25 phenolic chemicals, all the experimental animal ST1A forms showed substrate specificities similar to human ST1A3 rather than ST1A5. They showed high affinities toward p-nitrophenol and 6-hydroxymelatonin as found in human ST1A3. These forms also showed high activities toward umbelliferone and naringenin, but very low activities toward catecholamines, representative substrates of human ST1A5. Hepatic contents of experimental animal ST1A forms varied (66-250 pmol/mg of cytosolic protein) but showed the same order as observed with human ST1A3 (120 pmol/mg). Hepatic content of human ST1A5 was about 19-fold less than that of ST1A3. Therefore, ST1A forms identified in experimental animal species correspond to human ST1A3 functionally. For chemicals such as troglitazone and 2-amino-4'-hydroxy-1-methyl-6-phenylimidazo[4,5-b]pyridine, clear species differences were detected among the ST1A forms examined.

Amino Acid Sequence↗
PubMed2001

The efficacy of nafamostat mesilate on the performance of a hybrid-artificial liver using a polyurethane foam/porcine hepatocyte spheroid culture system in human plasma.

Nafamostat mesilate (FUT) is a protease inhibitor of complement activation. The present study investigates whether FUT protects porcine hepatocytes from being injured by human plasma in a multi-capillary polyurethane foam packed-bed culture system (MC-PUF) such as the hybrid-artificial liver (PUF-HAL). Human plasmas with 1 mM of added ammonia were perfused using a small-scale PUF-HAL with porcine hepatocytes. FUT was continuously infused (10 microg/ml, 50 microg/ml). The ammonia detoxification was maintained in human plasma for 24 hours and for 48 hours with FUT which suppressed the rapid increase of asparaginic acid aminotransferase (AST) and alanine aminotransferase (ALT). After 60 hours of perfusion, hepatocyte spheroids completely collapsed in the human plasma, but a small amount of hepatocyte spheroid was maintained by FUT. The effect of FUT was slightly greater at 50 microg/ml than at 10 microg/ml. Our results suggest that FUT has protective effects against porcine hepatocytes in human plasma, and our PUF-HAL using porcine hepatocytes can function in human plasma for about 48 hours with FUT.

Alanine Transaminase↗
PubMed2001

Correlation between loss of PTEN expression and Akt phosphorylation in endometrial carcinoma.

The tumor suppressor PTEN acts as a lipid phosphatase, regulates the phosphatidylinositol 3-kinase (PI3K)/Akt-signaling pathway, and modulates cell cycle progression and cell survival. Somatic mutations of PTEN have been reported in a variety of cancers, especially in endometrial carcinoma. To clarify whether and how PTEN and the PI3K/Akt pathway relates to endometrial carcinoma, we examined the expression of those pathway-related proteins in patients with endometrial carcinoma. Of 103 endometrial carcinomas, 37 (36%) showed negative immunohistochemical staining of PTEN. Western blotting revealed that the expression of PTEN in PTEN-negative cases was significantly lower compared with that in positive cases. In contrast, phospho-Akt level in negative cases was significantly higher. We found a significant inverse correlation between PTEN and phospho-Akt (r = -0.796). The expression of phospho-Bad was greater in negative cases, suggesting that Bad might be a target for AKT: The present study demonstrates the phosphorylation of Akt accompanied by the loss of PTEN in clinical specimens of endometrial carcinomas.

Carrier Proteins↗
PubMed2001

Lusitropic effect of MCC-135 is associated with improvement of sarcoplasmic reticulum function in ventricular muscles of rats with diabetic cardiomyopathy.

Effects of MCC-135 on contraction and relaxation properties and sarcoplasmic reticulum (SR) function were investigated in the failing ventricular muscle due to diabetic cardiomyopathy. Wistar rats were made diabetic by a single injection of streptozotocin (40 mg/kg i.v.). Seven months later, the left ventricular papillary muscle was isolated and isometric tension was measured. The skinned fiber with functional SR preserved was prepared by treatment of the papillary muscle with saponin and used to study SR Ca(2+) uptake, Ca(2+) release, and Ca(2+) leakage. In diabetic rats, developed tension (DT) was decreased, and 80% relaxation time (TR80) and time to peak tension (TTP) were increased compared with normal rats. MCC-135 decreased TR80 and TTP without significant effect on DT in diabetic rats, but not in normal rats. Isoproterenol increased DT, and decreased TTP and TR80 only in normal rats. In diabetic rats, SR Ca(2+) uptake and SR Ca(2+) release were decreased, and SR Ca(2+) leakage was increased compared with normal rats. MCC-135 increased SR Ca(2+) uptake and decreased SR Ca(2+) leakage in diabetic rats, but not in normal rats. SR Ca(2+) release was not affected by MCC-135 both in normal and diabetic rats. The combination of protein kinase A and cAMP increased SR Ca(2+) uptake only in normal rats. These results suggest that MCC-135 has a positive lusitropic effect that might be associated with enhanced Ca(2+) uptake into the SR and reduced Ca(2+) leakage from the SR. MCC-135 appears to be more beneficial in treating the failing myocardium with lusitropic abnormality than cAMP-increasing drugs.

Animals↗
PubMed2001

[Current status and future of surgical robotic systems].

In this review, we are commenting the current status and the future of surgical robotic systems. AESOP is a voice-controlled laparoscope manipulator that enables the "Solo-surgery". ZEUS is a master-slave manipulator that is characterized by its simplicity and lightness. da Vinci is another master-slave manipulator that has more range of freedom, therefore a surgeon can perform the operation with fewer difficulties. The technological development of high-quality and real-time 3D simulation, minimization of scopes and power saving techniques made these surgical robots realized. Although many pending matters such as lack of safety guideline or lack of accuracy of sensor/monitor have been raised in current surgical robotics, the development of the technologies may promise to resolve such matters in the future.

Forecasting↗
PubMed2001

A case of renal ptosis treated with hochu-ekki-to with improvement confirmed by excretory urography.

A 59-year-old woman visited our clinic with complaints of right back dull pain. Excretory urography showed bilateral renal ptosis (a 6 cm decrease in position of the right kidney and a 5 cm decrease of the left kidney). She was treated with 7.5 g/day of Hochu-ekki-to. After 6 months, her symptoms improved and after 8 months excretory urography showed a 3 cm decrease in the position of both kidneys. Hochu-ekki-to might be useful for the conservative therapy of renal ptosis.

Drugs, Chinese Herbal↗
PubMed2001

p53 gene status and chemosensitivity in ovarian cancer.

Recent studies suggest that drug induced apoptosis relates to the sensitivity. p53 gene, which has a pivotal role in inducing apoptosis, frequently mutates in ovarian cancer. Therefore, p53 gene status and chemosensitivity in epithelial ovarian cancer is discussed. Nonresponders to chemotherapy had mutations of the p53 gene more frequently (83% for nonresponders vs. 16% for responders) in patients with epithelial ovarian cancer undergoing platinum-base chemotherapy. Apoptotic index was significantly greater in tumors with wild-type p53 gene than those without the gene. p53 gene transduction markedly enhanced the sensitivity to cisplatin (CDDP) and CDDP-induced apoptosis, but did not affect the sensitivity to paclitaxel (PTX) nor PTX-induced apoptosis in ovarian cancer cells without p53 gene. The combination treatment with a recombinant adenovirus carrying a wild-type p53 gene (AxCAp53) and CDDP significantly suppressed tumor growth of ovarian cancer cells with and without p53 gene, compared with a single treatment of either AxCAp53 or CDDP in ovarian cancer xenograft. Apoptotic index was significantly higher and proliferating cell nuclear antigen labeling index was relatively lower in an ovarian cancer xenograft without p53 gene receiving combination treatment, compared with a single treatment of either CDDP or AxCAp53, suggesting that the transduction of p53 gene induces apoptosis, but does not enhance the DNA repair system. A significant survival advantage was observed in the combination treatment compared with other treatments in carcinoma peritonitis models. In conclusion, p53 gene status contributes the sensitivity to CDDP in ovarian cancer. Additionally, combination treatment of p53 gene transduction and CDDP may be an effective therapeutic modality for ovarian cancer without wild-type p53 gene.

Adenocarcinoma↗
PubMed2001

[Application of genetic diagnosis for colorectal cancer].

Recently, PCR techniques have been introduced for genetic diagnosis of colorectal cancer. The clinical significance of the genetic diagnosis of cancers includes preclinical diagnosis of hereditary cancers and viral tumors, prediction of malignancy and chemosensitivity focusing on expression profiling of related genes, and detection of micrometastasis in lymph node or bone marrow as well as of circulating tumor cells in peripheral blood targeting tumor-specific mRNA expression such as cytokeratin 19, 20 and CEA. In this report, molecular biological techniques for genetic diagnosis of colorectal cancer are discussed.

Apoptosis↗
PubMed2001

Mass preparation of primary porcine hepatocytes and the design of a hybrid artificial liver module using spheroid culture for a clinical trial.

To isolate a large number of porcine hepatocytes, we originally developed a mass preparation method that combined the usual collagenase perfusion method of a whole liver with a collagenase redigestion method of tissue fragments after liver perfusion. Using a pig of 10kg, collagenase perfusion only resulted in a yield of 63+/-78 x 10(8) total cells with a viability of 69.2+/-25.3 %, but our combined method had a yield of 167+/-31 x 10(8) total cells with a viability of 87.9+/-4.4% (mean +/- SD). Also, the combined method was applied to two pigs of 10kg body weight at the same time, and isolated 387+/-89 x 10(8) hepatocytes with a viability of 87.1+/-6.9% and a purity of 93.6+/-2.8 % in 11 experiments. We designed a large multi-capillary polyurethane foam (MC-PUF) packed-bed module containing 1 x 10(10) porcine hepatocytes on a clinical trial scale. The porcine hepatocytes in the module formed spherical multicellular aggregates (spheroids) of 200 - 500 microm diameter. Most hepatocytes forming spheroids were viable judged by fluorescein diacetate and ethidium bromide staining. The activities of ammonia removal, albumin secretion and oxygen consumption of the large MC-PUF module were the same as for a small MC-PUF module containing 2 x 10(8) porcine hepatocytes, and were maintained for at least 9 days of culture. These results show that a large MC-PUF module is successfully scaled up 50 times. In conclusion, we succeeded in developing a mass preparation method of porcine hepatocytes and a large hybrid artificial liver module on a clinical trial scale.

Animals↗
PubMed2001

Polyurethane foam/spheroid culture system using human hepatoblastoma cell line (Hep G2) as a possible new hybrid artificial liver.

The risk of xenozoonosis infections poses the greatest obstacle against the clinical application of hybrid artificial liver support system (HALSS). Primary human hepatocytes are an ideal source for HALSS, but the shortage of human livers available for hepatocyte isolation limits this modality. To resolve this issue, we used human hepatocytes with replication capacity (fetal hepatocytes, Hep G2, and Huh 7) in a polyurethane foam (PUF)/spheroid culture system in vitro, and analyzed liver functions such as ammonia removal and albumin synthesis capacity; results were compared to those of porcine hepatocytes. Human fetal hepatocytes, Hep G2, and Huh 7 formed spheroids spontaneously within 24 h in a PUF/spheroid culture system; ammonia removal activity (micromol/10(6) nuclei/h) was upregulated, as was albumin synthesis activity (microg/10(6) nuclei/day). In particular, Hep G2 spheroids demonstrated high ammonia removal and albumin synthesis activities: 85% of the ammonia removal activity and 171.7% of the albumin synthesis activity of porcine hepatocytes in the monolayer culture. These results indicate the possibility of the development of a multicapillary PUF (MC-PUF) packed-bed culture system of hepatocyte spheroids as a HALSS using Hep G2.

Albumins↗
PubMed2001

Regional difference in muscle fiber type and glucose uptake of mouse gastrocnemius at rest.

Regional differences in muscle fiber types and their glucose uptake in superficial, middle and deep regions of mouse gastrocnemius at rest were studied. The enzyme activities of succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (alpha-GPDH) and myofibrillar ATPase were used for the classification of each muscle fiber type. For the evaluations of glucose uptake, 2-deoxyglucose (2-DG) microradioautography and expression of the glucose transporter 4 (GLUT4) protein were applied. In superficial region of mouse gastrocnemius, all fibers were IIx or IIb and were low for 2-DG uptake and GLUT4 expression. They were anaerobic and fast twitch. In middle region, fibers showing low 2-DG uptake and small amounts of GLUT-4 protein (IIx and IIb) dominated (80.4%). Most fibers were anaerobic and fast twitch. Others were type IIc and IIa. In deep region, most fibers (86.9%) showed high 2-DG uptake and large amounts of GLUT4 protein (I, IIc and IIa). They were oxidative and slow twitch.

Adenosine Triphosphatases↗
PubMed2000

The impact of donor age on living donor liver transplantation.

BACKGROUND: The impact of the age of the donor on the outcome of living related liver transplantation is yet to be clarified. METHODS: During October 14, 1996 and December 20, 1999, 34 living related liver transplantations were performed. Of these, 26 cases were performed using the extended left lobe graft, which were classified into three groups; younger donor group (group Y, donor age < 30, n = 7), middle-aged donor group (group M, 30 < or = donor age <50, n=13), and older donor group (group O, donor age < 50, n = 6). Early allograft function and regeneration were compared between these groups. RESULTS: There was no difference in standard liver volume, and predicted or harvested graft size between the three groups. Although serum transaminase and total bilirubin levels within postoperative day 7 were not different between the groups, the prothrombin time on postoperative day 3 was significantly longer in group O than in group Y. One week after transplantation, group Y had significantly greater graft/standard liver volume ratio than group O, and greater graft volume than group M and O. One month after transplantation, however, there was no significant difference in such graft size parameters between the groups. Graft and patient survival were comparable between the three groups. CONCLUSION: Although function and regeneration of the allografts from older donors in living donor liver transplantation is worse than those of their younger counterparts, the outcome is not affected by the age of the liver.

Adult↗
PubMed2000

Selection of viable cardiomyocytes for cell transplantation using three-dimensional tissue culture.

BACKGROUND: We developed a three-dimensional cardiac tissue culture system to select viable and contractile cells for the purpose of cardiomyocyte transplantation. In this study we will show that reaggregation of cardiomyocytes in culture is an active process indicative of cardiomyocyte viability and functionality. METHODS: Myocardial tissue from newborn mice has been enzymatically digested, incubated in culture inserts, and studied by phase contrast microscopy, conventional histology, immunohistochemistry, electron microscopy, and TUNEL assay. RESULTS: Cells that are plated on nonadhesive surfaces, reaggregate to spontaneously contracting cell aggregates. The capacity to reaggregate was significantly dependent from the age of the tissue donor (P<0.0001) and on the method of enzymatic dissociation (P<0.0001). The majority of cells within the aggregates consisted of cardiomyocytes. After 24 hr incubation, significant amounts of laminin and fibronectin had been deposited between the cells. Ultrastructural analysis revealed viable cardiomyocytes attached to each other by tight junctions. The apoptotic rate within the aggregates was 11.4+/-4.6 vs. 44.5+/-10.5% immediately after dissociation (P<0.05). CONCLUSIONS: The capacity to form spontaneously contracting aggregates is an inherent characteristic of viable cardiomyocytes in 3-dimensional cultures, which could be successfully exploited for cellular cardiomyocyte transplantation.

Animals↗
PubMed2000

Domino liver transplantation from a living related donor.

BACKGROUND: Although domino liver transplantations (OLT) from cadaveric donors have been performed in about 50 cases since 1995, only one case in the Japanese literature has been reported on a domino OLT from a living related donor. The difficulties of the later surgery lie in the small size of the graft volume and the short length of the vascular cuffs in the graft. METHODS: The left lobe graft was procured from a 43-year-old younger brother of a familial amyloidotic polyneuropathy (FAP) patient. Next, the left lobe graft (510 g, 44% of the estimated standard liver volume of the FAP patient) was implanted into the 48-year-old female FAP patient. At surgery for the FAP patient, a sufficient length of the vascular cuffs was secured by an extended left lobe resection, although the right lobe graft was able to maintain sufficient vascular cuffs. The right lobe graft (720 g, 54% of the recipient's estimated standard liver volume) was then implanted in the 43-year-old male patient with liver cirrhosis and hepatocellular carcinoma (stage IV-A). RESULTS: The two recipients were discharged from the hospital 1 month after OLT. At 7 months after OLT, they are both doing well and the domino recipient is free of any tumor recurrence. CONCLUSION: A domino OLT from the living related donor can therefore be done safely when careful attention is paid to the graft volume and the length of the vascular cuffs for anastomosis.

Amyloid Neuropathies↗
PubMed2000

Amino acid sequence and some properties of phytolacain G, a cysteine protease from growing fruit of pokeweed, Phytolacca americana.

A protease, phytolacain G, has been found to appear on CM-Sepharose ion-exchange chromatography of greenish small-size fruits of pokeweed, Phytolacca americana L, from ca. 2 weeks after flowering, and increases during fruit enlargement. Reddish ripe fruit of the pokeweed contained both phytolacain G and R. The molecular mass of phytolacain G was estimated to be 25.5 kDa by SDS-PAGE. Its amino acid sequence was reconstructed by automated sequence analysis of the peptides obtained after cleavage with Achromobacter protease I, chymotrypsin, and cyanogen bromide. The enzyme is composed of 216 amino acid residues, of which it shares 152 identical amino acid residues (70%) with phytolacain R, 126 (58%) with melain G, 108 (50%) with papain, 106 (49%) with actinidain, and 96 (44%) with stem bromelain. The amino acid residues forming the substrate binding S(2) pocket of papain, Tyr67, Pro68, Trp69, Val133, and Phe207, were predicted to be replaced by Trp, Met, His, Ala, and Ser in phytolacain G, respectively. As a consequence of these substitutions, the S(2) pocket is expected to be less hydrophobic in phytolacain G than in papain.

Amino Acid Sequence↗
PubMed2000

The role of des-gamma-carboxy prothrombin levels in hepatocellular carcinoma and liver tissues.

We aimed to clarify the clinical significance of des-gamma-carboxy prothrombin (DCP) levels in both hepatocellular carcinoma (HCC) and liver tissues with a special reference to the relationship between DCP level in non-cancerous parts of the liver and the multicentric occurrence of HCC. Twenty-eight patients with HCC, who underwent hepatectomy, were studied. Surgical specimens were obtained from both HCC and non-cancerous liver of each patient. After the preparation of the liver tissues, including tissues with HCC, the DCP levels both in HCC and non-cancerous liver tissue were measured using an electro-chemiluminescence immunoassay. The correlation was investigated between DCP levels and other clinicopathological factors. The DCP level of HCC ranged from 55 to 77735 U/0.1 g tissue weight, with a median of 2801, while the DCP level of non-cancerous parts of the liver ranged from 24 to 721 U/0.1 g tissue weight, with a median of 86. The DCP level in the liver tissue in patients having a multicentric occurrence of HCC was significantly higher than that in patients without multicentric occurrence of HCC. The logarithm of the plasma DCP level correlated with that of the DCP level in HCC (correlation coefficient =0.46; P<0.05). No significant correlation was found between the DCP level in HCC and other clinicopathological parameters. The DCP level in non-cancerous parts of the liver with simultaneous multicentric occurrence of HCC was significantly higher than that in the liver without multicentric HCC. Furthermore, the DCP level in non-cancerous parts of the liver was one of the most important predictable factors of the multicentric occurrence of HCCs among various clinicopathological factors. Therefore, the DCP level may have an important role in hepatocarcinogenesis.

Aged↗