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Biomedical subjects

T Ishikawa

Publications and source records attributed to T Ishikawa.

At least 343 records · Page 19Linked to original sources
PubMed2000

The human multidrug resistance-associated protein (MRP) gene family: from biological function to drug molecular design.

The ATP-binding cassette transmembrane proteins play an important role in transport of drugs as well as of biologically active endogenous substances. The human multidrug resistance-associated protein (MRP) subfamily consists of at least six members, exhibiting a wide spectrum of biological functions. MRP1 operates as an ATP-dependent primary active transporter for substrates conjugated with glucuronide, sulfate or glutathione. Leukotriene C4 is an important endogenous substrate for MRP1. Glutathione serves as a cofactor in MRP1-mediated drug transport as well. Genes encoding both MRP1 and the catalytic subunit of gamma-glutamylcysteine synthetase (gamma-GCS) are coordinately regulated in cultured cancer cell lines as well as colorectal cancer tissues from colon cancer patients. The induction of MRP1 and gamma-GCS expression by oxidative stress varies among different cell lines, and p53 mutations are associated with elevated levels of induction. To modulate the transport function of MRP1, we have synthesized novel glutathione derivatives as photoreactive biochemical probes targeting the transporter protein. GIF-0019 restored the cellular sensitivity of MRP1-overexpressing drug-resistant cancer cells to anticancer prostaglandins in vitro, which was characterized by enhanced mRNA levels of the cyclin-dependent kinase inhibitor p21, suppressed c-myc expression and G1 arrest.

ATP-Binding Cassette Transporters↗
PubMed2000

High prevalence of hepatitis C in patients with thalassemia and patients with liver diseases in Myanmar (Burma).

We conducted Myanmar-Japan cooperation studies on hepatitis B and hepatitis C virus markers in patients with thalassemias and those with liver diseases. Among the 102 patients with liver diseases, 92% had a history of hepatitis B virus infection (antibody to hepatitis B core antigen positive), 35% were hepatitis B surface antigen positive, 39% were positive for anti-HCV. Among 28 patients with hepatocellular carcinoma, 46% had hepatitis B surface antigen, 21.4% had antibody to hepatitis C virus, and 7% were positive for both hepatitis B surface antigen and anti hepatitis C virus. The history of HCV infection among blood recipients at the Haematology Department of the Yangon General Hospital and at the Yangon Children's Hospital was found to be 55.5% and 46.7%, respectively, which is comparable to the history of hepatitis B infection (66.7% and 46.7%, respectively). This preliminary survey also encountered 2 cases positive for anti-HCV among 34 voluntary blood donors. This survey is the first one to report that hepatitis C is at the epidemic stage in Myanmar. As there is no effective treatment for hepatitis C in this country, a screening program for blood used in transfusion should be started immediately.

Adult↗
PubMed2000

Relations of empathy and social responsibility to guilt feelings among undergraduate students.

Empathy and social responsibility as related to guilt feelings were investigated among undergraduate students. Subjects (337 men and 353 women) were assessed for guilt feelings, empathy, and social responsibility. The Guilt Inventory was used to assess guilt feelings. Analysis indicated that scores on the two empathy subscales, Fantasy and Personal Distress, were related to rated Trait Guilt and State Guilt, whereas Social Responsibility scores were associated with those on Moral Stan dards of the Guilt Inventory.

Adolescent↗
PubMed2000

Change and 1-year maintenance of nutrient and food group intakes at a 12-week worksite dietary intervention trial for men at high risk of coronary heart disease.

We examined how dietary habits (i.e., intake of nutrients and food groups) were changed by intervention and how once adopted diets were maintained thereafter using the data of a 12-wk worksite dietary intervention trial for men at high risk of coronary heart disease (i.e., hypercholesterolemia, hyperglycemia, and/or overweight). Dietary habits were assessed pre- and post-intervention and 1 y follow-up points using a self-administered diet history questionnaire. The intervention method was a brief individual counseling based on the results of a pre-intervention assessment and a weekly distribution of newsletters. At the pre- and post-intervention points, a control group selected from the workers was used for comparison. The Keys score, and the changes in intake of saturated fatty acids (SFA), monounsaturated fatty acid, total fat, and cholesterol (the decrease), as well as dietary fiber, potassium, calcium, and iron (the increase) were significantly different between the intervention (n = 63) and control (n = 123) groups (p < 0.05). The changes were almost maintained with little recidivism at the 1 y follow-up point in the intervention group (i.e., for the decrease in SFA and Keys score, p < 0.001). The decrease in serum cholesterol level expected from the change in Keys score and body weight, taking possible regression to the mean into consideration, was almost identical to and slightly greater than (18%) those observed at the post-intervention and 1 y follow-up points, respectively. The results suggest that the favorable changes in dietary habits adopted during an intervention period were almost maintained for the subsequent 1 y period.

Adult↗
PubMed2000

Effect of alcohol intake on the levels of plasma homocysteine in healthy males.

Hyperhomocysteinemia in chronic alcoholics has been reported, but it remains unclear whether relatively low alcohol intake compared with the previous reports affects the plasma homocysteine level. To investigate this issue, we performed two studies, a population-based study and an alcohol withdrawal study. An analysis of plasma homocysteine levels in a population of 236 healthy males showed no significant association between alcohol consumption and other tested parameters. In the withdrawal study, the subjects with a history of daily alcohol consumption (81.8 +/- 33.0 g/d, mean +/- SD, 40-150g/d, range) abstained from alcohol for 4 wk. After withdrawal, the levels of serum gamma-glutamyl transpeptidase, aspartate aminotransferase, triglycerides, and high-density lipoprotein cholesterol significantly decreased, but the plasma homocysteine level did not change. These results suggest that alcohol intake, at least as far as the amount of beverages our study subjects consumed, has no effect on the plasma homocysteine level in healthy males.

Adult↗
PubMed2000

Contribution of angiogenesis to the progression of colon cancer: possible inhibitory effect of angiogenesis inhibitor TNP-470 on tumor growth and hepatic metastasis.

The contribution of angiogenesis to tumor growth and hepatic metastasis of colorectal cancer was investigated by means of immunohistochemical study and in vitro and in vivo experiments. Colorectal cancer specimens from 30 patients with hepatic metastasis and 39 patients without hepatic metastasis were studied by staining with antibodies against factor VIII-related antigen. Microvessel count in patients with liver metastasis was significantly higher than in those without liver metastasis (p<0.005). The effect of TNP-470 was evaluated with in vitro and in vivo experiments using human colon cancer cell line, LM and the highly hepatic metastasis cell line, LM-H5. The effect of TNP-470 on the proliferation of the cancer cells and human umbilical vein endothelial cells (HUVECs) was examined. TNP-470 inhibited more sensitively the proliferation of HUVECs than cancer cells in vitro. IC50 was approximately 3 pg/ml in HUVECs and approximately 2 microg/ml in cancer cells. The effect of TNP-470 on the growth of xenografts and liver metastases by LM-H5 in nude mice was examined. TNP-470 (30 mg/kg) was administered by subcutaneous injection every third day for 4 weeks. TNP-470 inhibited both the growth of xenograft and the hepatic metastasis. The number of metastatic foci in the liver was 78.2+/-30.1 in the control group and 20.6+/-16.5 in the treated group. These results suggest that TNP-470 is a potent agent to inhibit tumor growth and hepatic metastasis of colon cancer.

Adult↗
PubMed2000

Studies on anti-MRSA parenteral cephalosporins. I. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)- hydroxyiminoacetamido]-3-(substituted imidaz.

In order to improve the antibacterial activity of cefozopran (CZOP) against methicillin-resistant Staphylococcus aureus (MRSA), we initiated chemical modification to introduce a 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-hydroxyimino acetyl group at the C-7 position and a 3- or 6-substituted imidazo[1,2-b]pyridazinium or 5-substituted imidazo[1,2-a]pyridinium group at the C-3' position. Although this approach successfully enhanced the anti-MRSA activity of CZOP two to eight times, a slight decrease in the activity against Gram-negative bacteria including Pseudomonas aeruginosa was involved. Among the novel derivatives, 3-(6-aminoimidazo[1,2-b]pyridazinium-1-yl)methyl-7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)hydroxyiminoacetamido]-3-cephem-4-carboxylate (44a) showed an excellent balance of activity against MRSA and Gram-negative bacteria.

Animals↗
PubMed2000

Studies on anti-MRSA parenteral cephalosporins. II. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4- thiadiazol-3-yl)-2(Z)-alkoxyiminoacetamido]-3-(substituted imidaz.

In an effort to discover a novel cefozopran (CZOP) derivative having excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), we performed chemical modification of the alkoxyimino moiety and imidazo[1,2-b]pyridazinium group of CZOP. Among the prepared compounds, the cyclopentyloxyimino derivative 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-cyclopentyloxyiminoacetamido]-3-(3,6-diaminoimidazo[1,2-b]pyridazinium-1-yl)methyl-3-cephem-4-carboxylate (20 g) showed the most potent anti-MRSA activity, reflecting its high affinity (IC50 = 1.6 microg/ml) for penicillin binding protein 2' (PBP2'), although its anti-MRSA activity was slightly inferior to that of vancomycin (VCM). In experimental systemic infection in mice, however, 20 g showed activity comparable to that of VCM against MRSA. In addition, 20 g showed activity similar or slightly inferior to that of CZOP against Pseudomonas aeruginosa both in vitro and in vivo. Considering its favorable antibacterial activity profile, 20 g was considered to be the most promising CZOP derivative for further studies.

Animals↗
PubMed2000

Arborcandins A, B, C, D, E and F, novel 1,3-beta-glucan synthase inhibitors: production and biological activity.

Arborcandins A, B, C, D, E and F, which possess potent 1,3-beta-glucan synthase inhibitory activity, were isolated from the culture broth of a filamentous fungus, strain SANK 17397. Arborcandins are novel cyclic peptides, that are structurally different from known glucan synthase inhibitors such as echinocandins. The 1,3-beta-glucan synthases of Candida albicans and Aspergillus fumigatus were inhibited by arborcandins with IC50 ranging from 0.012 to 3 microg/ml. The apparent Ki value of arborcandin C for C. albicans and A. fumigatus were 0.12 microM and 0.016 microM, respectively. The inhibition against these two 1,3-beta-glucan synthases by arborcandin C was noncompetitive. These compounds exhibited potent fungicidal activity against Candida spp. with MIC ranging from 0.25 to 8 microg/ml. The growth of A. fumigatus was suppressed by arborcandins with concentrations ranging from 0.063 to 4 microg/ml.

Anti-Bacterial Agents↗
PubMed2000

Cytofluorometric nuclear DNA content analysis of breast tissues after frozen section diagnosis.

OBJECTIVE: To establish a suitable method for measurement of nuclear DNA content in breast tissues from frozen storage after frozen section diagnosis. STUDY DESIGN: For fundamental research, rat liver samples preserved in a deep freezer were used. Four protocols were used (1. fixation with 70% ethanol followed by naked nuclei preparation; 2. fixation with 10% neutral buffered formalin followed by naked nuclei preparation; 3. preparation for naked nuclei prior to fixation with 70% ethanol; and 4. preparation for naked nuclei prior to fixation with 70% neutral buffered formalin). For clinical research, 13 separate fresh frozen breast tissue samples were analyzed after frozen section diagnosis. One contained a malignant phyllodes tumor (MPT) consisting of 2 components, benign epithelial cells and malignant stromal cells; 3 were benign tumors containing fibroadenoma; and 9 cases were carcinomas, consisting of 5 scirrhous, 3 papillotubular and 1 mucinous. RESULTS: Protocols 1, 2 and 3 were not suitable methods for our purpose because remaining cytoplasm or cohesive nuclei were observed. In protocol 4 the cytoplasm was completely undetectable, and nuclei were suitably separated for nuclear DNA content measurement. Benign epithelial cell component nuclei presented a diploid pattern, and the malignant stromal cell component nuclei indicated a euploid pattern in MPT. All 3 cases of benign constituents in fibroadenoma showed a diploid pattern, as did the 3 carcinoma cases (1 mucinous, 1 scirrhous and 1 papillary). Four scirrhous and 2 papillary carcinomas showed an aneuploid pattern. CONCLUSION: Our findings show that it is possible to measure nuclear DNA content of human frozen storage tissues after frozen section diagnosis.

Animals↗
PubMed2000

Clinical significance of serum soluble intercellular adhesion molecule 1 in gastric cancer.

We studied the correlation between serum soluble intercellular molecule 1 (sICAM-1) and clinicopathological features in patients with gastric cancer. The impact of sICAM-1 on prognosis was also evaluated. The sera from 224 patients with gastric cancer, 44 healthy individuals, and 35 patients with benign gastrointestinal diseases (4 patients with submucosal stomach tumors, 6 patients with gastric ulcers, 1 patient with Crohn disease, 2 patients with ulcerative colitis, 7 patients with gall stones, 5 patients with chronic pancreatitis, and 10 patients with liver cirrhosis) were measured for sICAM-1 titer using a sandwich enzyme immunoassay method. There was no correlation between the serum titer of sICAM-1 and the age or gender of healthy controls. Among patients with benign gastrointestinal diseases, the patients with liver cirrhosis had a significantly higher mean serum sICAM-1 titer than that of healthy controls (P < 0.0001). The mean serum sICAM-1 titer of all patients with gastric cancer was not significantly different from that of healthy controls. However, among the patients with stage IV and recurrent disease, the serum sICAM-1 titer of those with hematogenous metastasis was significantly higher than that of patients without hematogenous metastasis (P = 0.001). The patients with a high serum sICAM-1 titer of more than 304 ng/ml (mean of healthy controls plus SD) showed a significantly worse prognosis than patients with a low serum sICAM-1 titer (P = 0.010). Nevertheless, serum sICAM-1 titer was not an independent predictor of prognosis by multivariate analysis. In conclusion, serum sICAM-1 cannot be used as a tumor marker for early diagnosis. However, sICAM-1 in sera may still be worthwhile to measure for monitoring hematogenous metastasis.

Adult↗
PubMed2000

Properties of hepatitis B virus genome recovered from Vietnamese patients with fulminant hepatitis in comparison with those of acute hepatitis.

Among the many mutations found in the hepatitis B virus (HBV) genome, some have been associated with fulminant hepatitis, as exemplified by precore-defective mutations. The aim of this study was to determine whether such mutations also are found in Vietnamese cases of fulminant hepatitis B. The full-genome nucleotide sequence of HBV in three patients with fulminant hepatitis (F-2, F-3, and F-6) and one with acute hepatitis (A-3), who were admitted to Cho Ray Hospital, Ho Chi Minh City, Vietnam was ascertained. Additionally, two patients with fulminant hepatitis (F-1 and F-7) and three with acute hepatitis (A-1, A-2, and A-5) were examined only for the precore/core region of HBV. Remarkably, the nonsense mutation at precore codon 28 (Trp82Stop) was found in four of the five patients with fulminant hepatitis, while all the acute hepatitis patients harbored wild type (one had a mixture of wild and mutant types). The missense mutations within the core region, Ile97Leu and Pro130Ile/Thr/Ser, were also remarkable in fulminant hepatitis. Only F-2 was free from these precore/core mutations, but F-2 was unique in that it possessed a chimeric genotype: it could be classified into genotype C as a whole, but its X region was of genotype B, like the other four fulminant hepatitis isolates (F-1, F-3, F-6, and F-7). The codon 41 of the X protein was Pro in all three fulminant hepatitis cases examined for this region, while it was Ser in the wild-type isolates of genotype B. Of note as negative data, the mutations C1653T and T1753M of the enhancer II (Enh II) and A1762T and G1764A of the precore/core promoter regions, once reported to be relevant to severe or fulminant hepatitis, were not found in the present cases. The results with the Vietnamese cases of fulminant hepatitis corroborated results of previous studies with respect to the mutations Trp28Stop of precore and Ile97Leu and Pro130Ile/Thr/Ser of core, but not for the mutations within Enh II and precore/core promoter region. Whether the Ser41Pro mutation in the X region of genotype B HBV is Vietnam-specific or disease-specific deserves further investigation.

Adult↗
PubMed2000

[Intraocular lens calculation for cataract treated with photorefractive keratectomy using ray tracing method].

PURPOSE: Conventional methods (such as the SRK-II formula) do not accurately calculate the power of the intraocular lens (IOL) after refractive surgery. Therefore, we compared a new formula including a ray tracing method to the conventional method for foldable IOL lens implantation. METHOD: Foldable IOLs (MA 60 BM) were implanted in 26 patients (32 eyes) using the phakoemulsification technique. The power of the IOL was measured preoperatively using the SRK-II formula in all cases. From the results of postoperative refractive errors of these cases, the power of IOL calculated by the ray tracing method was compared to the SRK-II formula. Cataract patients first treated with photorefractive keratectomy (PRK) received IOL implants using our ray tracing method and their postoperative refraction was measured. RESULTS: The average postoperative refractive error was 1.32 D in SRK-II formula, 0.95 D in the ray tracing method with Ray 1 used and 0.89 D with Ray 2 used. Postoperative refraction of both eyes first treated with PRK was--1.00 D. CONCLUSION: The average postoperative refractive error was reduced in the ray tracing method using Olsen's predicted ACD (Ray 2) compared to SRK-II formula. This new tracing method appears to be useful for determination of IOL power and it may be applied for IOL calculation for cataract surgery after refractive surgery.

Cataract↗
PubMed2000

Marked increase of trypsin(ogen) in serum of linitis plastica (gastric cancer, borrmann 4) patients.

Linitis plastica, or Borrmann 4 gastric cancer, shows very poor prognosis, and the reason has not been understood. In the present study, we examined serum levels of trypsin(ogen) in 44 gastric cancer patients, including 17 early gastric cancer, 18 non-Borrmann 4 advanced gastric cancer, and 9 Borrmann 4 gastric cancer, by using the RIA gnost Trypsin kit (Hoechst Japan, Tokyo, Japan), which was expected to detect trypsin-1, trypsin-2, trypsinogen-1, and trypsinogen-2 in sera. The trypsin(ogen) concentration was much higher in the patients with linitis plastica than in the other gross types of gastric cancer. Hypertrypsinemia was identified in approximately 60% of advanced gastric cancer cases. Lymph node involvement, liver metastasis, or poorly differentiated adenocarcinoma is an important factor of hypertrypsinemia. The serum trypsin(ogen) level in linitis plastica patients was 3484.4 +/- 2319.7 ng/ml (mean +/- SD), which was significantly higher not only than that of the early gastric cancer (384.1 +/- 92.1) but also the stage IV gastric cancer patients (578 +/- 440.4), excluding those with linitis plastica. The elevated serum trypsinogen level in linitis plastica patients may be related to the malignant behavior of this type of cancer cell. Serum trypsin(ogen) of linitis plastica shows significantly higher concentrations than do the other types of advanced gastric cancer. Therefore, serum concentration of trypsin(ogen) might be a good marker of gastric cancer of linitis plastica.

Humans↗
PubMed2000

[Efficacy of UFT in the treatment of para-aortic lymph node metastasis following gastric cancer surgery: case report].

The patient was a 68-year-old man who underwent pyloric gastrectomy for advanced stomach cancer on December 6, 1996. The histopathological diagnosis was poorly differentiated adenocarcinoma, ss, ly3, v1, n2 (+), and stage IIIa. Postoperative adjuvant chemotherapy consisted of short-term intravenous infusion of 5-FU, 320 mg/m2/day (= 480 mg/body) for 5 days beginning on postoperative day (POD) 1, and oral 5-FU, 200 mg/day, for 1 year beginning on POD 14. The preoperative CEA value was 316.2 ng, but it fluctuated below 10 ng postoperatively. About one year after the operation, the patient began to complain of epigastric pain, loss of appetite, and general malaise. CT of the upper abdomen revealed a 1.5-cm para-aortic lymph node, and the CEA value of 319.0 ng was abnormally high. 5-FU was stopped, oral UFT at 300 mg/day was started, and the patient's course was followed. Three months after the start of UFT, the lymph node had shrunk on CT (shrinkage rate: 66.7%), and the CEA value had decreased to 14.3 ng. As though corresponding to these changes there was a gradual decrease in the epigastric pain, general malaise, etc., and the patient's appetite also returned. There were no subsequent elevations in the CEA values or increases in the size of the para-aortic lymph nodes, and the patient's general condition was favorably maintained. UFT appeared to be effective against the lymph node metastasis around the aorta in this case.

Adenocarcinoma↗