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Biomedical subjects

M Monden

Publications and source records attributed to M Monden.

At least 199 records · Page 11Linked to original sources
PubMed1998

Rho and Rab small G proteins coordinately reorganize stress fibers and focal adhesions in MDCK cells.

The Rho subfamily of the Rho small G protein family (Rho) regulates formation of stress fibers and focal adhesions in many types of cultured cells. In moving cells, dynamic and coordinate disassembly and reassembly of stress fibers and focal adhesions are observed, but the precise mechanisms in the regulation of these processes are poorly understood. We previously showed that 12-O-tetradecanoylphorbol-13-acetate (TPA) first induced disassembly of stress fibers and focal adhesions followed by their reassembly in MDCK cells. The reassembled stress fibers showed radial-like morphology that was apparently different from the original. We analyzed here the mechanisms of these TPA-induced processes. Rho inactivation and activation were necessary for the TPA-induced disassembly and reassembly, respectively, of stress fibers and focal adhesions. Both inactivation and activation of the Rac subfamily of the Rho family (Rac) inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly. Moreover, microinjection or transient expression of Rab GDI, a regulator of all the Rab small G protein family members, inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly, indicating that, furthermore, activation of some Rab family members is necessary for their TPA-induced reassembly. Of the Rab family members, at least Rab5 activation was necessary for the TPA-induced reassembly of stress fibers and focal adhesions. The TPA-induced, small G protein-mediated reorganization of stress fibers and focal adhesions was closely related to the TPA-induced cell motility. These results indicate that the Rho and Rab family members coordinately regulate the TPA-induced reorganization of stress fibers and focal adhesions that may cause cell motility.

Actins↗
PubMed1998

Image guidance of breast cancer surgery using 3-D ultrasound images and augmented reality visualization.

This paper describes augmented reality visualization for the guidance of breast-conservative cancer surgery using ultrasonic images acquired in the operating room just before surgical resection. By combining an optical three-dimensional (3-D) position sensor, the position and orientation of each ultrasonic cross section are precisely measured to reconstruct geometrically accurate 3-D tumor models from the acquired ultrasonic images. Similarly, the 3-D position and orientation of a video camera are obtained to integrate video and ultrasonic images in a geometrically accurate manner. Superimposing the 3-D tumor models onto live video images of the patient's breast enables the surgeon to perceive the exact 3-D position of the tumor, including irregular cancer invasions which cannot be perceived by touch, as if it were visible through the breast skin. Using the resultant visualization, the surgeon can determine the region for surgical resection in a more objective and accurate manner, thereby minimizing the risk of a relapse and maximizing breast conservation. The system was shown to be effective in experiments using phantom and clinical data.

Breast Neoplasms↗
PubMed1998

Cloning and mapping of SMARCA5 encoding hSNF2H, a novel human homologue of Drosophila ISWI.

We have isolated a novel cDNA encoding a peptide with 86% sequence homology to hSNF2L protein, a previously isolated human homologue of Drosophila ISWI. This gene, designated SMARCA5, contained an open reading frame of 3,156 nucleotides encoding a 1,052 amino-acid peptide (hSNF2H). As this product also revealed a significant (73%) identity in amino acid sequence to ISWI, a key component of chromatin-remodeling factors in Drosophila, hSNF2H may be another human homologue of this protein and, as such, could be involved in chromatin remodeling in humans. An ATPase domain characteristic of the SWI2/SNF2 family of proteins was highly conserved in ISWI, hSNF2L, and hSNF2H. Northern-blot analysis demonstrated ubiquitous expression of 5.1-kb and 4.1-kb transcripts of the hSNF2H gene. This gene was mapped by FISH to chromosome bands 4q31.1-->q31.2.

Adenosine Triphosphatases↗
PubMed1998

Possible involvement of m-calpain in vascular smooth muscle cell proliferation.

Vascular smooth muscle cell (VSMC) proliferation still remains a poorly understood process, although it is believed to play a critical role in pathological states, including atherosclerosis and hypertension. Several reports have suggested that proteases may be directly involved in this process; however, it was still unclear which protease is responsible for VSMC proliferation. In this study, by use of a cell-permeable calpain inhibitor (calpeptin; benzyloxycarbonyl-Leu-nLeu-H), its analogue (benzyloxycarbonyl-Leu-Met-H), the cell-impermeable serine protease inhibitor leupeptin, and antisense oligonucleotide against m-calpain to inhibit proliferation of primarily cultured human VSMCs, we investigated whether calcium-activated neutral protease (calpain) is involved in VSMC proliferation. Calpeptin and its analogue, more specific for m-calpain, equally inhibited the proliferation of VSMCs in a dose-related manner, whereas a more limited antiproliferative effect was observed in leupeptin-treated VSMCs. Antisense oligonucleotide against m-calpain, but not scrambled antisense, dose-dependently inhibited m-calpain expression and proliferation of VSMCs. Maximal inhibition was an approximately 50% reduction of cell number and m-calpain antigen observed at 50 micromol/L of antisense oligonucleotide. Calpeptin or antisense oligonucleotide against m-calpain increased the expression of the endogenous calpain substrate pp125FAK (focal adhesion kinase), whereas the expression of the endogenous calpain inhibitor calpastatin was not affected. These results suggest that the proliferation of VSMCs requires protease activity, some of which is due to m-calpain.

Calcium-Binding Proteins↗
PubMed1998

Extraction and analysis of diagnostically useful proteins from formalin-fixed, paraffin-embedded tissue sections.

We describe and discuss a method of protein extraction for Western blot analysis from formalin-fixed, paraffin-embedded tissue sections. From 5-mm2 50-micron-thick tissue sections, an abundance of proteins could be extracted by incubating the sections in lysis buffer containing 2% sodium dodecyl sulfate (SDS) at 100C for 20 min followed by incubation at 60C for 2 hr. Extracts yielded discernible protein bands ranging from 10 kD to 120 kD as identified by SDS-polyacrylamide gel electrophoresis (PAGE). Western blot analysis successfully detected membrane-bound protein such as E-cadherin, cytosolic protein such as beta-catenin, and nuclear proteins including proliferating cell nuclear antigen (PCNA), mutant-type p53, cyclin D1, cyclin E, and cyclin-dependent kinases (CDKs). With this technique, we could examine cyclin D1 and CDK2 expression in small adenomas compared with cancer tissues and normal mucosa. The simple method of protein extraction described here should make it possible to use large-scale archives of formalin-fixed, paraffin-embedded samples for Western blot analysis, and its application could lead to detailed analysis of protein expression. This new technique should yield valuable information for molecular biology.

Adenoma↗
PubMed1998

Cdk2/cdc2 expression in colon carcinogenesis and effects of cdk2/cdc2 inhibitor in colon cancer cells.

Cyclin dependent kinases propel the cell cycle in collaboration with cyclins. We have examined the expression of cdk2/cdc2 in adenoma and focal carcinoma in adenomatous tissue to explore their role in tumorigenesis of colorectum. Immunohistochemical study revealed that cdk2/cdc2 was overexpressed in a subsets of adenoma (14/50; 28.0%) but this overexpression was much more obvious in focal carcinoma (13/15; 86.7%). These results suggest that cdk2/cdc2 is remarkably upregulated together with a malignant change. In an effort to demonstrate a significant role for cdk2/cdc2 in colon cancer, we investigated growth and apoptosis with butyrolactone I, a specific inhibitor for cdk2/cdc2, using 4 colon carcinoma cell lines (HCT116, LoVo, HT29, Colo 320DM). Butyrolactone I inhibited proliferation of all colon carcinoma cell lines at 100 microM and it induced apoptosis in LoVo cell line with induction of p53. Our findings suggest that inhibition of cdk2/cdc2 may be a useful strategy against colon cancer.

4-Butyrolactone↗
PubMed1998

Effect of cyclin D1 and associated proteins on proliferation of esophageal squamous cell carcinoma.

Cyclin D1, which functionally competes with the tumor suppressor genes retinoblastoma (Rb) and p16INK4, is widely recognized as an oncogene. P27KIP1, which inhibits the cyclin D1-CDK4 complex, is also a putative tumor suppressor gene. In order to evaluate the regulatory interaction of these molecules, a retrospective series of tissues from 66 patients with esophageal squamous cell carcinoma was evaluated immunohistochemically for the expressions of cyclin D1, Rb, p16INK4 and p27KIP1. The expressions of these molecules were correlated with the proliferation cell nuclear antigen (PCNA) index as an indicator of cell proliferation. Cyclin D1 was overexpressed (++) in 28 cases (42%), Rb was lost (-) in 19 cases (24%), p16INK4 was lost (-) in 37 cases (56%) and p27KIP1 was lost (-) in 27 cases (41%). Taken together, disorder of at least one or more of these molecules was observed in 62 cases (92%). Expression of cyclin D1 and p16INK4 was negatively correlated (p<0.03), while expression of cyclin D1 and p27KIP1 was positively correlated (p<0.0004). We found strong overall correlation between expression of cyclin D1 and the PCNA index (p<0.0001), however expression of p16INK4 and p27KIP1 was significantly correlated with the PCNA index in tumors devoid of cyclin D1 overexpression (p<0.03 and p<0.02 respectively). Thus, it was found that cyclin D1 plays a major role and closely related to abnormal cell proliferation in esophageal cancer, however assessment of p16INK4 and p27KIP1 status, particularly in tumors devoid of cyclin D1 overexpression, is necessary for comprehensive evaluation of cancer cell proliferation. Furthermore, expression of cyclin D1 is correlated with that of p16INK4 and p27KIP1 in squamous cell carcinoma of the esophagus.

Aged↗
PubMed1998

[Organ preservation].

Organ preservation is currently performed by simple cold storage or continuous hypothermic perfusion. Cold storage using University of Wisconsin (UW) solution greatly prolongs the successful preservation period for abdominal organs such as the kidney, liver, and pancreas. Thoracic organs (heart, lung), however, can be preserved for only several hours even with UW solution. As a result of improvements in organ transplantation, the number of patients on waiting lists has grown rapidly. Unfortunately, many patients die while waiting for donor organs, and expansion of the donor pool is mandatory. Possible solutions to the shortage of donor organs include the use of marginal donors and non-heart-beating donors. For this purpose, more sophisticated methods of organ preservation are needed, and therefore extensive investigations using current technologies including gene transfer should be performed. Every effort should be made to accommodate the preferences of donors.

Adenosine↗
PubMed1998

Detection of K-ras gene mutations in plasma DNA of patients with pancreatic adenocarcinoma: correlation with clinicopathological features.

We investigated the presence of K-ras gene mutation in plasma DNA and assessed its clinical value in patients with pancreatic adenocarcinoma. Mutations in codon 12 of the K-ras gene were examined by mutant allele-specific amplification method using DNA extracted from surgical specimens and plasma samples of 21 patients with pancreatic adenocarcinoma. K-ras gene mutation was detected in 15 of 21 (71%) primary tumors. In 9 of 15 (60%) patients with K-ras gene mutation-positive tumors, an identical mutation was detected in the plasma DNA. None of four patients with chronic pancreatitis or five healthy subjects had such mutations in plasma DNA. Tumors positive for K-ras gene mutation in plasma DNA were significantly larger (P = 0.04) and less likely to result in a curative cure after surgical resection (P = 0.09) than those negative for the mutation. Other clinicopathological features, including age, sex, histological type, mode of invasion, and metastasis, did not correlate with K-ras gene mutations in plasma DNA. Treatment resulted in disappearance of K-ras gene mutations in plasma DNA in six of nine (67%) patients. Three patients with a persistently positive K-ras gene mutation in pre- and post-treatment plasma samples were likely to show early recurrence or have a progressive disease. Our findings suggest that K-ras gene mutation can be detected in plasma DNA of patients with pancreatic adenocarcinoma. Detection of K-ras mutations in plasma may be clinically useful for evaluating tumor burden and efficacy of treatment.

Adenocarcinoma↗
PubMed1998

[Molecular biological assessment of susceptibility to colorectal cancer].

There are two entities in the predisposition for colorectal cancer. One is the hereditary colorectal cancers which include familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC), and others. In the case of these hereditary diseases, genetic testing to detect germline mutation in the causative gene in family members is useful for identifying possible gene carriers. For the diagnosis of HNPCC, the present clinical criteria are not sufficient and analysis of DNA replication error (RER) could be useful. Another entity is genetic sensitivity to environmental carcinogens. In particular, the polymorphism of the genes encoding drug-metabolizing enzymes has been shown to be important in recent years. The fast acetylator genotype of N-acetyltransferase (NAT) genes and the null genotype of the glutathione S-transferase M1 gene have been reported to be associated with increased risk of colon cancer. In the strategy against colon cancer, it is extremely important to identify high-risk individuals so that we can prevent cancers or detect them in earlier stages.

Adenomatous Polyposis Coli↗
PubMed1998

Transaxillary endoscopic partial mastectomy for comparatively early-stage breast cancer. An early experience.

For optimal cosmetic results in breast cancer surgery, we developed an alternative operation using endoscopy to remove tumors through a small single incision remote from the breast itself. The tumor is endoscopically resected with electrocautery and low constant suction through a short incision in the axilla, 5 cm long, after which axillary dissection is performed through the same wound in the usual manner, under visualization by the naked eye. Primary reconstruction of the breast is performed with the remaining mammary gland and a subcutaneous fat flap on the serratus muscle. Seven patients underwent this surgery. The postoperative shape of the breasts was judged to be cosmetically satisfactory, and the surgical wounds were not visible from the front in all cases. This operation has the same therapeutic oncological effect as a standard lumpectomy and, in addition, offers a greater cosmetic advantage in cases of early breast cancer.

Adult↗
PubMed1998

[PyNPase expression and cancer progression in the colorectum].

We analyzed PyNPase expression discriminating between cancer and tumor stroma of the colorectum by Western blotting using a newly developed extraction method from microdissected tissue sections fixed with buffered formalin. Analysis of 98 colorectal cancers revealed that PyNPase was as high as 70.2 +/- 18.5 unit/mg protein in the stroma fraction (SF), whereas it was 45.1 +/- 10.5 in the cancer fraction (CF) (p < 0.0001). Vessel density was correlated with PyNPase in the SF but not in the CF. In stage IIIb, 11 cases expressing a high level of PyNPase in the CF showed poorer prognosis than 10 cases with low-level PyNPase expression (p < 0.05), although the level of PyNPase expression in the SF did not affected the patients prognosis. Immunohistochemical examination indicated that PyNPase in the SF was mainly produced by macrophages (M phi), and therefore we investigated the profile of PyNPase production by M phi. In in vitro experiments PyNPase production by M phi was greatly enhanced by stimulation with OK-432, and the culture supernatant had the ability to convert 5'DFUR to 5-FU.

Antineoplastic Agents↗
PubMed1998

[Results of clinical study with epirubicin hydrochloride injectable solution in hepatoma].

A 10-center cooperative clinical study with a new formulation of epirubicin hydrochloride injectable solution (Epirubicin-RTU) was conducted in patients with hepatocellular carcinoma. Epirubicin-RTU 60 mg/m2 was injected into the hepatic artery and a three-week drug-free interval followed. Of 15 patients with hepatocellular carcinoma registered in this study, 14 patients were eligible, and they all completed the entire course. The objective was to investigate the safety of treatment with Epirubicin-RTU in 14 eligible patients. The adverse drug reactions frequently observed in these 14 eligible cases were leukopenia, neutropenia, thrombocytopenia, alopecia, and fever. They were all reversible and tolerable. With these results. Epirubicin-RTU was considered to be a safe pharmaceutical product to inject into the hepatic artery.

Adult↗
PubMed1998

[Laparoscopic splenectomy for a massive splenomegaly using a transcatheter technique].

Laparoscopic splenectomy can be performed more safely today, and therefore it is becoming the first-choice technique for splenectomy when the spleen is of normal size. However, for massive splenomegaly there have been few reports of the use of this technique and its safety has not been confirmed. We performed laparoscopic splenectomy for massive splenomegaly with transarterial embolization of the splenic artery before surgery. A 37-year-old man underwent splenectomy due to the lack of effect of an approximately 4-month course of chemotherapy for chronic myeloid leukemia whose spleen was over 20 cm in length. Before surgery, splenic artery embolization was performed to prevent intraoperative bleeding and to debulk the spleen. Under general anesthesia the patient was positioned in the lateral decubitus position lying on the right side. There was no bleeding from the capsule of the spleen throughout the procedure and no intraoperative complications occurred. Blood loss was 100 ml, and the weight of the resected spleen was 1,100 g. The postoperative course was uneventful. We conclude that laparoscopic splenectomy is safe and feasible in cases of splenomegaly, when combined with preoperative embolization of the splenic artery.

Adult↗