Efficacy of screening for gastric cancer in a Korean adult population: a case-control study

While gastric cancer is the most common malignancy in the Korean adult population, little is known of the efficacy of gastric cancer screening among Koreans. To study the efficacy of gastric cancer screening, this case-control study was conducted. From November 1996 to July 1998, 441 newly diagnosed gastric cancer (321 advanced, 120 early) patients were enrolled at the Department of General Surgery and 107 controls were enrolled at the inpatient Department of Family Medicine and Otolaryngology. History of gastric examinations and possible risk factors were collected through interview with a structured questionnaire. Patients with advanced gastric cancer were 61% less likely to have had a gastric examination than those with early gastric cancer (OR 0.39; 95%CI 0.23-0.65). Patients with advanced gastric cancer were 53% less likely to have had a gastric examination within two years of diagnosis (OR 0.47; 95%CI 0.23-0.98) and 69% less likely to have had a gastric examination within three years of diagnosis (OR 0.31; 95%CI 0.11-0.86). The data, showing a significant relationship between the history of gastric examinations and severity of gastric cancer, suggests that gastric cancer screening is effective in catching gastric cancer at early stages. It also suggests less than three years for screening interval.

Phosphatidylinositol 3-kinase stimulates muscle differentiation by activating p38 mitogen-activated protein kinase

The activation of both phosphatidylinositol 3-kinase (PI3-kinase) and p38 mitogen-activated protein kinase (p38 MAPK) is required for muscle differentiation. However, it is not known whether the signals from these two kinases interact during this process. In this work, we have investigated this using H9c2 cardiac myoblasts. The p38 MAPK-specific inhibitor SB203580 blocked muscle differentiation and suppressed the expression of myogenin and myosin heavy chain in a concentration-dependent manner. Consistent with this, expression of a wild-type p38 MAPK (Ha-p38) or a constitutively active MAPK kinase 6 (MKK6(glu)) promoted the rate of differentiation into multinucleated myotubes. LY294002, a PI3-kinase inhibitor, suppressed in a dose-dependent manner not only muscle differentiation but also activation of p38 MAPK. In addition, expression of a constitutively active form of PI3-kinase (p110*) enhanced myotube formation and p38 MAPK activation, while expression of a dominant negative form of PI3-kinase (Deltap85) attenuated these responses. Furthermore, SB203580 suppressed differentiation of H9c2 cells expressing p110*. Interestingly, LY294002 also suppressed differentiation of H9c2 cells expressing Ha-p38 or MKK6(glu). However, SB203580 did not affect PI3-kinase activity, suggesting that PI3-kinase myogenic signaling to p38 MAPK is unidirectional. Taken together, we concluded that PI3-kinase activates p38 MAPK, which in turn stimulates muscle differentiation, but that p38 MAPK does not substitute for PI3-kinase in this process.

Statistical analysis of in vivo rodent micronucleus assay

The in vivo rodent micronucleus assay (MNC) is widely used as a cytogenetic assay to detect the clastogenic activity of a chemical in vivo. MNC is one of three tests in a battery recommended by the fourth International Conference on Harmonization (ICH4) of Genotoxicity Guidelines. As such it has been accepted by many regulatory authorities. However, the determination of a positive result in a genotoxicity test, including MNC, has been an issue of debate among toxicologists and biometricians. In this presentation we compare several statistical procedures that have been suggested for the analysis of MNC data and indicate which one is the most powerful. The standard protocol of MNC has at least three dose levels plus the control dose and uses at least four animals per group. For each animal, 2000 polychromatic erythrocytes (PCE) are counted. Two statistical procedures can be employed, either alone or jointly, for the analysis of the MNC dose-response curve. These are the Cochran-Armitage (C-A) trend test and the Dunnett type test. For performing Dunnett type tests, toxicologists often use negative historical control rate for the estimate of the concurrent negative control rate. Some toxicologists emphasize the reproducibility of assay results instead of the dose-response relationship for the important criterion [J. Ashby, H. Tinwell, Mutat. Res. 327 (1995) 49-55; for the rebuttal see M. Hayashi, T. Sofuni, Mutat. Res. 331 (1995) 173-174]. The following three procedures are currently employed in toxicology labs for the evaluation of MNC result. The assay response is deemed positive if it is detected by (i) the C-A trend test alone, (ii) both the C-A trend test and the Dunnett type test and (iii) either the C-A trend test or the Dunnett type test. Using Monte Carlo simulation, we first find for each procedure, sizes of tests which yield the experiment-wise type I error rate of 0.05 and show that the procedure (ii) is the most powerful against the alternatives of monotone increase. The procedure (ii) which originated from Hayashi's three-step procedure was coded in C and termed 'MNC'. The MNC software program is available in the public domain through the ftp.

The statistical analysis of the in vitro chromosome aberration assay using Chinese hamster ovary cells

The purpose of the in vitro chromosome aberration assay (ABS) is to determine whether the test compound is a clastogen, i.e. induces structural changes in chromosomes. Details of this assay can be found in Galloway et al. [S.M. Galloway, M. Aardema, M. Ishidate Jr, J.L. Ivett, D.J. Kirkland, M. Takeshi, P. Mosesso, T. Sofuni, Mutation Res. 312 (1994) 241-261]. The standard design consists of a negative control and at least three positive dose groups. At each dose, a sample, say 200, of metaphase cells is examined microscopically and cells exhibiting at least one type of chromosome aberration are identified. Using Chinese hamster ovary cells, Margolin et al. [B.H. Margolin, M.A. Resnick, J.Y. Rimpo, P. Archer, S.M. Galloway, A.D. Bloom, E. Zeiger, Environ. Mutagen. 8 (1986) 183-204] and Richardson et al. [C. Richardson, D.A. Williams, J.A. Allen, G. Amphlett, D.O. Chanter, B. Phillips, Analysis of data from in vitro cytogenetic assays, in: D.J. Kirkland (Ed.), Statistical Evaluation of Mutagenicity Test Data, Cambridge University Press, Cambridge, 1989, pp. 141-154] demonstrated that a binomial sampling model could be used to describe the proportion of cells with chromosome aberrations.Statisticians and toxicologists have also suggested evaluation criteria for the dose response pattern of ABS. Margolin et al. [B.H. Margolin, M.A. Resnick, J.Y. Rimpo, P. Archer, S.M. Galloway, A.D. Bloom, E. Zeiger, Environ. Mutagen. 8 (1986) 183-204] suggested one use the Cochran-Armitage trend test. Sofuni et al. [T. Sofuni, A. Matsuoka, M. Sawada, M. Ishidate Jr, E. Zeiger, M.D. Shelby, Mutation Res. 241 (1990) 175-213] considered the dose response to be (strong) positive if it had two significant doses out of three dose groups and decided it was weakly positive if it had only one significant dose and there was a significant trend. The criterion of Galloway et al. for a positive response was a clear dose-related increase in cells with structural aberrations in one experiment or a reproducible single positive dose [S.M. Galloway, M. Aardema, M. Ishidate Jr, J.L. Ivett, D.J. Kirkland, M. Takeshi, P. Mosesso, T. Sofuni, Mutation Res. 312 (1994) 241-261]. We formulate the above three procedures in terms of a Cochran-Armitage trend test and a Dunnett type test. We then compare the performance of these three procedures in terms of a Monte Carlo simulation study. We then develop a software program from the chosen procedure for its ease of use by statisticians and toxicologists.

Tissue urokinase-type plasminogen activator receptor levels in breast cancer

Cancer invasion is induced by several proteolytic enzyme systems associated with the destruction of basement membrane and extracellular matrix. Urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) have been reported as prognostic factors in breast cancer patients and plasminogen activation is regulated by various factors such as uPAR and growth factors. Thus, we examined the tissue levels of urokinase-type plasminogen activator receptor (uPAR) in breast cancer patients. Tissue uPAR levels were measured by ELISA assay in 268 breast cancer patients. The median and mean values of tissue uPAR level in breast cancer were 3.5 ng/mg cytosol protein and 4.8+/-3.6 ng/mg cytosol protein, respectively. Tissue uPAR level was the highest in T1 stage, but there was no statistical significance between the T stages (p>0.05), nor in nodal stage, in the value of uPAR according to progression. And the value of uPAR expression was not associated with estrogen and progesterone receptor status, number of involved node and percent of node involvement. In TNM stage, tissue uPAR levels were higher in patients with stage I-II than in patients with stage III-IV (p=0.027). In univariate analysis, nodal factor (p=0.002) and TNM stage (p=0.0004) were significant. But, multivariate analysis showed that TNM stage was the only significant prognostic factor (p=0.0002). These results suggest that uPAR is mainly associated with initial tumor invasion and other factors might be involved in later stages of cancer progression.

Survival and function of rat hepatocytes cocultured with nonparenchymal cells or sinusoidal endothelial cells on biodegradable polymers under flow conditions

BACKGROUND/PURPOSE

The authors have investigated hepatocyte transplantation using biodegradable polymer scaffolds as a possible treatment of end-stage liver disease. The purpose of this study was to investigate the survival rate and function of hepatocytes alone or cocultured with other cell types on 3-dimensional biodegradable polymers for 7 days under continuous flow conditions in vitro.

METHODS

Hepatocytes (group 1, n = 8), hepatocytes with nonparenchymal cells (group 2, n = 7), or hepatocytes with sinusoidal endothelial cells (group 3, n = 6) were isolated from Lewis rats and seeded onto the polymer scaffolds. The polymer devices subsequently were placed under continuous flow conditions for 7 days. Albumin production from the constructs was measured each day, and urea nitrogen synthesis was examined on day 7. The devices also were examined by histology at day 7.

RESULTS

Histology results showed the presence of numerous viable hepatocytes on polymer devices, with no differences in hepatocyte viability between the 3 groups. Albumin secretion in the culture medium gradually decreased by day 7. There also were no significant differences in albumin production or urea nitrogen synthesis between the 3 groups at day 7.

CONCLUSIONS

Hepatocytes could survive on the 3-dimensional polymer scaffolds under flow conditions for 7 days, and albumin secretion and urea synthesis of hepatocytes were seen at day 7. Nonparenchymal cells and sinusoidal endothelial cells had no measurable effect on hepatocyte function in our continuous flow culture system.

Transduction effect of antisense K-ras on malignant phenotypes in gastric cancer cells

The antitumoral effects of antisense RNA to K-ras were investigated in gastric cancer cell lines by examining the level of K-ras expression and the tumorigenicity in vitro and in vivo. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), DNA sequencing, and immunoblotting analysis revealed that YCC-1 gastric cancer cells overexpressed wild type K-ras, whereas YCC-2 cells had a homozygous mutation in codon 12 from GGT (glycine) to AGT (serine), while SNU-1 cells had a heterozygous mutation to GAT (asparagine) in the identical position. Both YCC-1 and YCC-2 cells were transduced by LNC-AS/K-ras containing the antisense 2.2 kb genomic K-ras DNA fragment covering exon 2 and exon 3 specific for K-ras. The application of antisense K-ras significantly downregulated the expression of K-ras and had no influence on the expression of either H-ras or N-ras. The antisense-transduced YCC-2 cells grew considerably slower than the control group transduced by LNCX, whereas the growth inhibition of antisense-transduced YCC-1 cells was less prominent than that of transduced YCC-2 cells. In addition, the tumorigenicity of YCC-2 cells transduced by LNC-AS/K-ras was totally lost. Therefore, our results imply that the specific inhibition of K-ras p21 protein can be accomplished by introducing the antisense covering the K-ras- specific region to gastric cancer cells with aberrant K-ras expression, resulting in a reduction of the growth rate and suppression of tumorigenicity.

Effects of 5-fluorouracil and leucovorin in the treatment of pancreatic-biliary tract adenocarcinomas

Adenocarcinomas of the pancreas and biliary tract are highly malignant neoplasms, which are found in the advanced stage. Chemotherapy commonly plays a palliative role in the treatment of pancreatic and biliary tract cancers. 5-Fluorouracil (5-FU) is the most widely studied single agent; the response rate of 5-FU is only 20%. Recently, some reports presented interesting results, in which 5-FU, modulated with levofolinic acid (leucovorin), was active in patients with colorectal cancer. In relation, we performed a phase II study of 5-FU, modulated with leucovorin, in patients affected by advanced pancreatic or biliary tract cancer. Fifty-one patients with nonresectable carcinomas of the pancreas or biliary tract admitted to Korea University Hospital between May 1995 and December 1998 were included in this study. Chemotherapy consisted of leucovorin 25 mg/m2/day by 2-hour intravenous infusion, followed by 5-FU 375 mg/m2/day by bolus intravenous infusion, from day I to day 5. The treatment was repeated every 3 to 4 weeks. A total of 51 eligible patients with advanced adenocarcinoma of the pancreas or biliary tract were enrolled. Of 23 enrolled patients with pancreatic adenocarcinoma, one patient showed complete remission with a survival duration of 13 months (response duration was 9 months). Three patients had partial responses (PRs) with survival times of 6, 12, and 15 months, respectively. The overall response rate was 17.4% (95% confidence interval [CI], 7.2%-36.2%). The median time of overall survival was 6 months (range: 1-15 months). Of 28 enrolled patients with biliary tract cancer, complete responses were observed in 2 patients (7.1%) with survival time of 14 and 16 months, respectively. Seven patients had PRs with a median survival of 8 months. The overall response rate was 32.1% (95% CI, 20.3%-57.5%). The median time of overall survival was 6 months (range: 1-16 months). The most prominent toxicity was mucositis. Hematologic toxicity was less severe. 5-Fluorouracil in modulation with intravenous leucovorin is well tolerated by patients with stage IV pancreatic adenocarcinoma or biliary tract cancer. Although the response rate for patients with pancreatic adenocarcinoma is not better than that achieved using 5-FU monochemotherapy, the 32.1% overall response rate achieved in patients with biliary tract cancer suggests that 5-FU modulation with leucovorin is active in biliary tract cancer.

B cell lymphomas of C57L/J mice; the role of natural killer cells and T helper cells in lymphoma development and growth

The Hodgkin's-like Type B neoplasms which arise spontaneously in aging C57L mice (25% incidence at 21 months of age) were first reported over 40 years ago, but since then relatively little has been published about these lymphomas. Based on previous studies in SJL mice, we investigated the phenotypic and functional properties of C57L-derived lymphomas in relation to Mtv29-encoded vSAg expression by the tumor cells, and their ability to stimulate TCR Vbeta-restricted T cells. The cell surface phenotype of the C57L lymphomas indicates a B cell origin (sIg(+), MHC II(+)). These B lymphoma cells also express co-stimulatory molecules [B7-1 (CD80) and HSA (CD24)], and stimulate marked proliferation of syngeneic CD4(+) T cells. C57L B lymphoma cells exhibit Mtv-encoded mRNA by northern analysis, and also stimulate IL-2 production from Vbeta16(+) T cell hybrids, suggesting a role for Mtv 29 in this syngeneic T cell response. After transfer to syngeneic recipients, primary C57L lymphomas grow slowly, if at all. However, tumor growth is greatly accelerated by pretreatment of C57L recipients with anti-asialo GM1 antibody (but not anti-CD8 mAb), suggesting that NK cells play a major role in inhibiting lymphoma growth. If, in addition to anti-asialo GM1, the mice are also pretreated with anti-CD4 mAb, tumor growth is markedly inhibited, indicating that the lymphoma-responsive syngeneic CD4(+) T cells promote tumor growth. Therefore, although the vSAg-induced response stimulated by vSAg29 expressing lymphoma cells in syngeneic TCR Vbeta-restricted CD4(+) T cells is an important etiologic factor in this type of B cell neoplasm both in C57L and in SJL mice, the final outcome of the spontaneous neoplastic process appears strongly influenced by endogenous NK activity in aging mice.

Combining chondrocytes and smooth muscle cells to engineer hybrid soft tissue constructs

Engineering new tissues using cell transplantation may provide a valuable tool for reconstructive surgery applications. Chondrocyte transplantation in particular has been successfully used to engineer new tissue masses due to the low metabolic requirements of these cells. However, the engineered cartilaginous tissue is too rigid for many soft tissue applications. We propose that hybrid tissue engineered from chondrocytes and smooth muscle cells could reflect mechanical properties intermediate between these two cell types. In this study, rat aortic smooth muscle cells and pig auricular chondrocytes were co-cultured on polyglycolic acid fiber-based matrices to address this hypothesis. Mixed cell suspensions were seeded by agitating the polymer matrices and a cell suspension with an orbital shaker. After seeding, cell-polymer constructs were cultured in stirred bioreactors for 8 weeks. The cell density and extracellular matrix (collagen, elastin, and glycosaminoglycan) content of the engineered tissues were determined biochemically. After 8 weeks in culture, the hybrid tissue had a high cell density (5.8 x 108 cells/cm(3)), and elastin (519 microg/g wet tissue sample), collagen (272 microg/g wet tissue sample), and glycosaminoglycan (GAG; 10 microg/g wet tissue sample) content. Mechanical testing indicated the compressive modulus of the hybrid tissues after 8 weeks to be 40.8 +/- 4.1 kPa and the equilibrium compressive modulus to be 8.4 +/- 0.8 kPa. Thus, these hybrid tissues exhibited intermediate stiffness; they were less stiff than native cartilage but stiffer than native smooth muscle tissue. This tissue engineering approach may be useful to engineer tissues for a variety of reconstructive surgery applications.

High-dose mouse immunoglobulin G administration suppresses Theiler's murine encephalomyelitis virus-induced demyelinating disease

We studied the effect of high-dose mouse IgG on TMEV-induced demyelinating disease (TMEV-IDD). We injected TMEV intracerebrally into susceptible SJL/J mice and induced TMEV-IDD. Mouse IgG were injected intraperitonealy, and clinical course and various immunological indicators were studied. The results show that TMEV-IDD was significantly suppressed both clinically and histologically (P<0.01) when IgG were administered in the effector phase. The delayed type hypersensitivity and T cell proliferative response specific for TMEV were decreased by this treatment. In an ELISPOT assay, the number of TNF-alpha producing lymphocytes in the spinal cords was low in high-dose IgG treated mice compared with PBS treated control mice. These data suggest that administration of IgG suppresses TMEV-IDD and may be promising treatment to prevent exacerbation of human multiple sclerosis.

The E-cadherin gene (CDH1) variants T340A and L599V in gastric and colorectal cancer patients in Korea

INTRODUCTION

Germline mutations in E-cadherin (CDH1) have been reported in families with early onset, diffuse gastric cancer. More recently, mutations in CDH1 have been described in colorectal cancer cell lines.

AIMS

We have investigated if germline mutations in CDH1 occur among different groups of Korean gastric and colorectal cancer patients, with and without a positive family history.

METHODS

We studied 131 patients and 168 normal controls (88 Korean and 80 non-Korean). Patients were divided into five groups: group I, 20 gastric cancer patients with a family history; group II, 26 colorectal cancer patients with a family history of gastric cancer (those from familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC) kindred were excluded); group III, 16 HNPCC patients without identified germline mutations in hMLH1 and hMSH2; group IV, 35 gastric cancer patients without a family history; and group V, 34 colorectal cancer patients without a family history. Polymerase chain reaction, single strand conformational polymorphism analysis, direct sequencing, and genotyping for identified variants were performed.

RESULTS

Several germline changes in CDH1 were found. In addition to previously described polymorphisms, we found three novel changes, two of which were missense changes (T340A and L599V). T340A was present in one patient in group III and one in group V. L599V was present in one patient in group II, in two in group III, and in one in group IV. T340A was not found in normal controls while L599V was present in two of 88 Korean controls. Patients with these variants may appear to have a tendency to early onset cancer with a positive family history, although differences in frequencies did not reach statistical significance. Genotyping results suggest that these variants might have a common origin, particularly T340A.

CONCLUSION

We have described two new missense germline variants in CDH1 in various groups of Korean gastrointestinal cancer patients. Further work is required to assess if these variants increase the risk of gastrointestinal cancer.

Clonal expansion of infiltrating T cells in the spinal cords of SJL/J mice infected with Theiler's virus

Intracerebral infection of susceptible mice with Theiler's murine encephalomyelitis virus results in immune-mediated inflammatory demyelination in the white matter and consequent clinical symptoms. This system has been utilized as an important virus model for human multiple sclerosis. Although the potential involvement of virus-specific Th cells has been studied extensively, very little is known about the nature of T cells infiltrating the CNS during viral infection and their role in the development of demyelinating disease. In this study, the clonal nature of T cells in the spinal cord during the disease course was analyzed using size spectratyping and sequencing of the TCR beta-chain CDR3 region. These studies clearly indicate that T cells are clonally expanded in the CNS after viral infection, although the overall TCR repertoire appears to be diverse. The clonal expansion appears to be Ag-driven in that it includes Th cells specific for known viral epitopes. Interestingly, such restricted accumulation of T cells was not detectable in the infiltrates of mice with proteolipid protein peptide-induced experimental autoimmune encephalomyelitis. The initial T cell repertoire (7-9 days postinfection) seems to be more diverse than that observed in the later stage (65 days) of virally induced demyelination, despite the more restricted utilization of Vbeta subfamilies. These results strongly suggest continuous stimulation and clonal expansion of virus-specific T cells in the CNS of Theiler's murine encephalomyelitis virus-infected mice during the entire course of demyelinating disease.

Subcutaneous and musculoskeletal sparganosis: imaging characteristics and pathologic correlation

OBJECTIVE

To document the imaging characteristics of subcutaneous and musculoskeletal sparganosis.

DESIGN AND PATIENTS

Ten patients with musculoskeletal sparganosis were examined, with a variety of imaging modalities including MRI (n=6), ultrasonography (n=8), plain radiography (n=7) and CT (n=1). Pathologic correlation was carried out in all cases.

RESULTS

Nine lesions involved soft tissues, of which seven were in the thigh, two in the trunk and one involved a vertebral body. The majority of the lesions in soft tissue were confined to the subcutaneous layer but two extended deep into underlying muscles. Sonography revealed low-echoic serpiginous tubular tracts (8/8), and an intraluminal echogenic structure (4/8). MRI revealed multiple serpiginous tubular tracts and peripheral rim enhancement. Two patients showed perilesional soft tissue edema. Pathologically, the lesion consisted of a larva surrounded by three layers of inflammation: an inner epithelioid granulomatous cell layer, middle chronic inflammatory cell layers, and an outer fibrous layer.

CONCLUSION

The study suggests that if serpiginous tubular tracts are seen at imaging studies, musculoskeletal sparganosis should be included in the differential diagnosis.

The relationship between virological characteristics of hepatitis C virus (HCV) and reactivity to the regional specific proteins of HCV

BACKGROUND

Although the polyproteins of hepatitis C virus(HCV) are processed and formed in nearly equimolar amounts, individual functional proteins have a discrepancy in their time of appearance following HCV infection and eliciting immune response. This study was conducted to compare the reactivity toward regional specific HCV protein in relation to virological characteristics, including HCV genotype and HCV replication.

METHODS

Sera from forty-five patients with chronic HCV infection were analyzed through the experiments of the recombinant immunoblot assay(RIBA-2), HCV genotyping and HCV RNA quantitation.

RESULTS

The frequencies of seropositivity to C22-3, C33C, C100-3 and 5-1-1 proteins were 91.1%, 91.1%, 64.4% and 53.3%, respectively, of all the patients, and thus the antibodies to C22-3 and C33C proteins were found more frequently (p < 0.05). The antibody responses between core or NS3 proteins and NS4 proteins showed more discrepancy in the HCC group than that in the CH group, implying a possibility of oncogenic potential of core or NS3 gene in hepatocarcinogenesis. The detection rate of antibodies to C22-3 and C33C, in accordance with serum HCV RNA levels, was significantly higher in highly viremic patients than that in low viremic patients (p < 0.05). Antibodies to C22-3, C33C, C100-3 and 5-1-1 were also found more frequently in patients with HCV genotype 1b, compared to those with HCV genotype 2a (p < 0.05).

CONCLUSION

These results suggest that antibody detection of HCV may depend on the virological characteristics of HCV, the levels of HCV replication and HCV genotype and, therefore, HCV RNA detection using RT-PCR technique is essential for confirmatory diagnosis for HCV infection. Furthermore, the HCV core or NS3 Protein may play important role in hepatocarcinogenesis.

Scaffolds for engineering smooth muscle under cyclic mechanical strain conditions

Cyclic mechanical strain has been demonstrated to enhance the development and function of engineered smooth muscle (SM) tissues, but appropriate scaffolds for engineering tissues under conditions of cyclic strain are currently lacking. These scaffolds must display elastic behavior, and be capable of inducing an appropriate smooth muscle cell (SMC) phenotype in response to mechanical signals. In this study, we have characterized several scaffold types commonly utilized in tissue engineering applications in order to select scaffolds that exhibit elastic properties under appropriate cyclic strain conditions. The ability of the scaffolds to promote an appropriate SMC phenotype in engineered SM tissues under cyclic strain conditions was subsequently analyzed. Poly(L-lactic acid)-bonded polyglycolide fiber-based scaffolds and type I collagen sponges exhibited partially elastic mechanical properties under cyclic strain conditions, although the synthetic polymer scaffolds demonstrated significant permanent deformation after extended times of cyclic strain application. SM tissues engineered with type I collagen sponges subjected to cyclic strain were found to contain more elastin than control tissues, and the SMCs in these tissues exhibited a contractile phenotype. In contrast, SMCs in control tissues exhibited a structure more consistent with the nondifferentiated, synthetic phenotype. These studies indicate the appropriate choice of a scaffold for engineering tissues in a mechanically dynamic environment is dependent on the time frame of the mechanical stimulation, and elastic scaffolds allow for mechanically directed control of cell phenotype in engineered tissues.

One-pot construction of medium- and large-sized ring substituted furans. Efficient conversion to dibenzofurans, coumestans, and 4-pyrones

New efficient synthesis of medium- and large-sized ring substituted furans is achieved by 1,3-dicarbonyl compounds with vinyl sulfides in the presence of Ag(2)CO(3)/Celite (Fétizon's reagent) in a one-pot procedure. The synthesized furans can be further converted to biologically interesting compounds such as dibenzofurans, coumestans, benzofuroquinolinone, and 4-pyrone.

Long-term follow-up of tissue-engineered intestine after anastomosis to native small bowel

BACKGROUND

Our laboratory has investigated the fabrication of a tissue-engineered intestine using biodegradable polymer scaffolds. Previously we reported that isolated intestinal epithelial organoid units on biodegradable polymer scaffolds formed cysts and the neointestine was successfully anastomosed to the native small bowel. The purpose of this study was to observe the development of tissue-engineered intestine after anastomosis and to demonstrate the effect of the anastomosis over a 9-month period.

METHODS

Microporous biodegradable polymer tubes were created from polyglycolic acid. Intestinal epithelial organoid units were harvested from neonatal Lewis rats and seeded onto the polymers, which were implanted into the abdominal cavity of adult male Lewis rats followed by 75% small bowel resection (n=24). Three weeks after implantation, the unit/polymer constructs were anastomosed to the native jejunum in a side-to-side fashion. The anastomosed tissue-engineered intestine was measured by laparotomy 10, 24, and 36 weeks after the implantation (n= 14). During the laparotomy, all rats with an obstruction in their anastomosis were killed and excluded from the statistical analysis. Another five rats were also killed at 10 and 36 weeks for histological and morphometric studies.

RESULTS

All analyzed rats survived this study and significantly increased their body weight by 36 weeks. Obstruction of the anastomosis was observed in one rat at 24 weeks and in two rats at 36 weeks; however, the anastomosis was patent in the other 11 rats by 36 weeks. The tissue-engineered intestine of these 11 rats increased in length and diameter at 10, 24, and 36 weeks after anastomosis; there were statistically significant differences between each time point except between the length of 10 and 24 weeks (P<0.016 by Wilcoxon signed rank test). Histologically the inner surface of the tissue-engineered intestine was lined with well-developed neomucosa at 10 and 36 weeks; however, there were small bare areas lacking neomucosa in the tissue-engineered intestine at 36 weeks. Morphometric analysis demonstrated no significant differences in villus number, villus height, and surface length of the neomucosa at 10 and 36 weeks.

CONCLUSIONS

Anastomosis between tissue-engineered intestine and native small bowel resulted in no complications after operation and maintained a high patency rate for up to 36 weeks. The tissue-engineered intestine increased in size and was lined with well-developed neomucosa for the duration of the study.

Structure elucidation and antifungal activity of an anthracycline antibiotic, daunomycin, isolated from Actinomadura roseola

The actinomycete strain Ao108 producing antifungal metabolites active against some plant pathogenic fungi was identified as Actinomadura roseola, based on the analyses of morphological and physiological characteristics. The antibiotic Da2B that showed a strong antifungal activity was isolated from the culture broth and mycelial mats of A. roseola strain Ao108 using various chromatographic procedures. On the basis of (1)H NMR, (13)C NMR, and 2-D NMR correlation data, the antibiotic Da2B was confirmed to have the structure of an anthracycline antibiotic, daunomycin. In vitro antimicrobial spectrum tests showed that the antibiotic Da2B had substantial inhibitory activity (10 microg mL(-)(1) of MICs) against mycelial growth of Phytophthora capsici and Rhizoctonia solani. The antibiotic also showed antiyeast activity against Saccharomyces cerevisiae, but the growth of Candida albicans was not affected. Antibacterial activity was found only against Gram-positive bacteria. In the further evaluation of in vivo efficacy, application of the antibiotic Da2B effectively inhibited the development of Phytophthora blight in pepper plants. However, the control efficacy of the antibiotic against Phytophthora infection was somewhat less than that of metalaxyl. The antibiotic Da2B did not show any phytotoxicity on pepper plants even at 500 microg mL(-)(1).

Microsatellite instability and mutations of E2F-4 in hepatocellular carcinoma from Korea

It has been suggested that genetic changes in cancers are related to genomic instability. To evaluate a possible correlation between growth-regulatory genes and genomic instability in HCC, we investigated microsatellite instability and mutations of TGF-beta type II receptor (TGF-beta RII) and E2F-4 genes in each pair of tumor and surrounding nontumor liver tissues, collected from 19 patients with HCC. By the identification of mutations in six different genetic loci (D1S170, D2S123, D4S395, D13S126, D13S260, and D16S402), one or more alterations in microsatellite markers were identified in 13/19 (68%) hepatocellular carcinoma specimens. When two repeated sequences of TGF-beta RII gene, poly(A)(10) tract in exon 8 and poly(GT)(3) tract in exon 9, were analyzed by polymerase chain reaction-single strand conformational polymorphism, none of the 19 hepatocellular carcinoma specimens showed mutations. When amplicons of poly(AGC)(13) tract of E2F-4 were analyzed by cloning and automated sequencing, 5/19 (36%) hepatocellular carcinomas showed deletion mutation in one or two AGC repeats and such mutations were identified only among cases with microsatellite instability. These results suggest that both microsatellite instability and mutations of E2F-4 occur commonly in hepatocellular carcinoma and play an important role in hepatocarcinogenesis.

Split-step time-domain analysis of optical waveguide devices composed of a directional coupler and gratings

An extended split-step time-domain model for composite coupling structures is reported. Time-dependent coupled-wave equations are solved by splitting of the operators for phase accumulation, forward directional coupling, and reverse Bragg reflection. Through an analysis of an add-drop filter based on a grating-written directional-coupler structure, the proposed modeling method is shown to be an order of magnitude more efficient than the previous methods.

Brainstem frequency-following response and simple motor reaction time

Simple motor reaction times (RT) in humans show marked trial-to-trial variations. In the present study, a brief tone (400 Hz, 37.5 ms duration) that was the imperative stimulus in a RT paradigm evoked the brainstem frequency-following response (FFR). Horizontal and vertical montage FFRs were recorded to evaluate neural responses with putative origins in auditory nerve and central brainstem, respectively. The main question concerned the possible relationship between trial-to-trial variations in RT speed and FFR response properties. The results showed a reliable pattern in which fast RT trials yielded larger amplitudes (relative to slow trials) in earlier milliseconds of the FFR, and slow RT trials yielded relatively larger amplitudes in later milliseconds of the response. These results support the conclusion that early processing in the auditory brainstem is not automatic and invariant. Rather, short-latency evoked potentials appear to reflect trial-to-trial variations related to events far removed from the first synapse of sensory coding, perhaps depending upon cortically mediated influences such as cognition or attention.