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Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 253 records · Page 14Linked to original sources

The Vienna classification of gastrointestinal epithelial neoplasia.

BACKGROUND: Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions. AIM: To develop common worldwide terminology for gastrointestinal epithelial neoplasia. METHODS: Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology. RESULTS: The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond). CONCLUSION: The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.

Adenoma↗

Cardiac dysfunction and long-term prognosis in patients with nonobstructive hypertrophic cardiomyopathy and abnormal (123)I-15- (p-Iodophenyl)-3(R,S)-methylpentadecanoic acid myocardial scintigraphy.

To evaluate the relationship between myocardial scintigraphic abnormalities based on (123)I-radioiodinated 15-(p-iodophenyl)-3(R, S)-methylpentadecanoic acid (BMIPP) uptake and cardiac function and the relationship between these abnormalities and long-term prognosis in patients with hypertrophic cardiomyopathy (HCM), 27 patients with nonobstructive HCM underwent BMIPP myocardial scintigraphic study, echocardiography, and exercise radionuclide study. Based on the extent of BMIPP scintigraphic defects, the patients were divided into two groups: Group A (n = 19) patients had no or small defects, and group B (n = 8) patients had moderate to large defects. Cardiac events were recorded over an average period of 64 months. The left ventricular end-diastolic and end-systolic dimensions were significantly greater in group B than in group A. The fractional shortening in group B was less than in group A (p = 0.0002). The BMIPP score and fractional shortening at rest correlated significantly (p < 0.05). The BMIPP score and the change in ejection fraction between rest and peak exercise correlated significantly (p < 0.05). While only 1 cardiac event occurred in the 19 patients in group A during a mean follow-up period of 64 months, 6 cardiac events occurred in the 8 patients in group B. The 84-month event-free survival rate was 94.4% in group A and 14.6% in group B (p < 0.01). These results suggest that patients with HCM and moderate to large defects as assessed by BMIPP myocardial scintigraphy have decreased cardiac function and a poor prognosis.

Adult↗

Neutralization of prostaglandin E1 intravenous solution reduces infusion phlebitis.

Previous studies have shown moderate or severe phlebitis at the site of venipuncture in some patients who receiving prostaglandin E1 (PGE1) infusion therapy. Such phlebitis is sometimes severe enough to necessitate the cessation of PGE1 therapy. This study investigated how to continue PGE1 infusion therapy for 3 weeks with tolerable phlebitis. Although a 60 microg dose of PGE1 is usually dissolved in 500 mL of fluid to avoid phlebitis, we used 200 mL to prevent volume overload. This PGE1 solution was neutralized to pH 7.4 with 4 mL of 7% sodium bicarbonate. We examined the frequency and severity of phlebitis among patients who received a 2-h PGE1 infusion twice daily. Eighteen patients who were hospitalized for peripheral vascular disease between June 1998 and May 1999 were studied. All of them were men and their mean age was 63.3 +/- 8.9 years (range: 47-78 years). Fourteen patients had arteriosclerosis obliterans and four had Buerger's disease. When the severity of phlebitis was determined according to Dinley's criteria, two patients (11%) had grade 0, four patients (22%) had grade 1, eleven patients (61%) had grade 2, and one patient (6%) had grade 3 phlebitis. Usually, PGE1 infusion therapy is stopped when phlebitis reaches grade 4 or more, but there were no such cases in this study. We also found that aging was significantly correlated with a decrease in the severity of phlebitis (Spearman's rank correlation test: r = -0.545, p = 0.0193).

Adult↗

Identification of an alpha-tubulin mutant of fission yeast from gamma-tubulin-interacting protein screening: genetic evidence for alpha-/gamma-tubulin interaction.

gamma-Tubulin has been determined to be a central element of microtubule nucleation and, thus, indispensable for cellular organization of the microtubule. Utilizing the fact that human gamma-tubulin can function in the fission yeast Schizosaccharomyces pombe, we have generated a unique mutant screening procedure which can specifically select mutants of genes encoding gamma-tubulin-interacting proteins. One of the isolated mutants, cs76, turned out to carry a mutation in the alpha 1-tubulin gene (nda2(+)). This result suggests a direct interaction between the alpha- and gamma-tubulins. We located the mutation site in the nda2 gene and characterized the mutant phenotype. Our results demonstrate the importance of the alpha-/gamma-tubulin interaction in microtubule nucleation and should complement previous knowledge.

Alleles↗

A computer program for pharmacokinetics based on maximum likelihood estimation using the gamma distribution with a probability density function: comparison with the normal distribution.

A computer program is described for maximum likelihood estimation within the gamma or normal distribution which can be used to estimate pharmacokinetic parameters. Pharmacokinetic analysis using this proposed program was investigated by the Monte Carlo method. The assumed pharmacokinetic models were a one-compartment intravenous model and an oral model. The simulated drug concentrations were generated using a 10% S.D. based on the gamma or normal distribution. The gamma or normal distribution was adopted as the probability density function (p.d.f.) to estimate model parameters. The Powell method was used to maximize the logarithmic likelihood. There were no differences in the estimated parameters in terms of statistical and frequency distributions between the gamma and normal distributions using the generated data and the p.d.f. distributions. However, the number of failures to calculate the parameters using the p.d.f. with the normal distribution was more than five times that using the gamma distribution. This result suggests that it may be necessary to evaluate the validity of results computed using the maximum likelihood estimation based on a normal distribution as a data error distribution and p.d.f.

Algorithms↗

Synthesis of (10Z)- and (10E)-19-fluoro-1alpha,25-dihydroxyvitamin D3: compounds to probe vitamin D conformation in receptor complex by 19F-NMR.

To study the interaction of vitamin D with its receptor by 19F-NMR, (5Z,10Z)- and (5Z,10E)-19-fluoro-1alpha,25-dihydroxyvitamin D3 were synthesized starting from vitamin D2 via electrophilic fluorination of vitamin D-SO2 adducts as the key step. Regio- and stereoselective electrophilic fluorination at C(19) of vitamin D-SO2 adducts was achieved under the conditions using (PhSO2)2NF and bulky bases. The stereochemistry of the addition and elimination of SO2 of various vitamin D derivatives was studied in detail. SO2 causes Z-E isomerization of the 5,6-double bond of vitamin D and adds to the resulting (5E)-isomer from the sterically less hindered side opposite to the substituent at C(1). Elimination of SO2 from 19-substituted vitamin D-SO2 adducts proceeded exclusively in a suprafacial manner with respect to the diene part under either thermal or reductive conditions. Dye-sensitized photochemical isomerization of 19-fluorovitamin D derivatives was studied in detail. The rapid isomerization at the 5,6-double bond was followed by the slow isomerization at the 10,19-double bond to yield the (5E,10Z)-isomer (by nomenclature of the 1-OH derivatives) as the major product. (10Z)- and (10E)-19-Fluorovitamin Ds were also interconverted thermally probably via the corresponding previtamin D by 1,7-sigmatropic isomerization.

Fluorine↗

Endothelial nitric oxide synthase gene mutation and human leukocyte antigen analyzed in three cases of familial vasospastic angina pectoris.

A 50-year-old woman with rest angina underwent cardiac catheterization; coronary angiography in the presence of acetylcholine revealed 99% coronary spasm of the proximal left anterior descending artery. The patient's 82-year-old mother was also admitted to hospital with rest angina. Her Holter electrocardiogram showed ST-segment elevation during the attack at rest and coronary angiography showed 99% spasm of the right coronary artery and 90% spasm of the left coronary artery. Both women complained of chest pain during the spasm, which was accompanied by ST-segment depression. The 62-year-old brother of the original patient was also found to have coronary spasm of the left coronary artery. Human leukocyte antigen was analyzed in the 2 women: A2, B51, CW1, DR8 and DQ1 were common factors. A Glu298Asp point mutation of the endothelial nitric oxide synthase gene was investigated in both parents, their 2 daughters and 2 sons, but was not detected in the 3 patients, and was detected only in the 90-year-old father who did not suffer from angina. Nor was the T-786-C mutation found in the 3 cases. Other causes of familial spasm need to be elucidated.

Aged↗

Slowly progressive heart failure due to subepicardial myocardial fibrosis in a patient with chronic pericardial effusion.

A 65-year-old woman was admitted to hospital because of orthopnea. She had been followed-up for chronic pericardial effusion detected by echocardiography 10 years previously. Initial echocardiography showed that the left ventricular diastolic diameter (LVDd) was 39 mm and percent fractional shortening (%FS) was 33.3%. Neither fluid samples nor a pericardial biopsy specimen identified the etiology. Cardiac tamponade was not evident, and C-reactive protein and creatine-kinase values were within normal limits. During follow-up, the %FS decreased gradually, but the LVDd remained unchanged. On admission, echocardiography showed that the %FS was 12.5% and LVDd was 40 mm. She developed intractable hyponatremic heart failure with bilateral pleural effusion. Autopsy findings revealed that infiltration of small lymphocytes in the epicardium had penetrated into the subepicardial myocardium. The subepicardial myocardium and the interventricular septal myocardium were diffusely replaced by fibrosis, which could have induced restrictive diastolic heart failure and reduced left ventricular contractility. The fibrosis was not detected in the epicardium itself nor the subendocardial myocardium. This is the first report describing diffuse subepicardial myocardial fibrosis in a patient with chronic pericardial effusion and progressive heart failure.

Cardiac Output, Low↗

Microvascular ischemia in patients with myotonic dystrophy.

Two women with myotonic dystrophy underwent dipyridamole thallium-201 (201Tl) myocardial perfusion imaging, after which one patient developed flat T waves in lead I and aV(L), and inverted T waves in leads V(2-6). The other patient developed a nonspecific intraventricular block that progressed to complete left bundle branch block and was associated with chest discomfort. Reversible scintigraphic defects were observed in both women. Although there was evidence that suggested myocardial ischemia on the ECG changes and 201Tl scintigraphic findings, coronary angiography demonstrated no significant stenoses in either patient. These findings suggest that microvascular dysfunction may lead to myocardial ischemia and conduction disturbances in patients with myotonic dystrophy.

Electrocardiography↗

Diagnostic usefulness of the post-exercise systolic blood pressure response for the detection of coronary artery disease in patients with diabetes mellitus.

Patients with diabetes mellitus (DM) often have a positive result on exercise testing despite a normal coronary arteriogram, which indicates that exercise-induced ST depression is not always an accurate indicator of the presence of coronary artery disease (CAD) in such patients. The present study evaluated the usefulness of the post-exercise systolic blood pressure (SBP) response for the detection of CAD in 47 consecutive patients with DM. Significant stenotic lesions were detected by angiography in 25 patients; 18 of these had true positive (TP) exercise testing results, and 7 had false negative (FN) results. No significant stenotic lesions were detected in the remaining 22 patients and of these 10 had true negative (TN) exercise testing results, and 12 had false positive (FP) results. The SBP ratio (SBP after 3 min of recovery divided by the SBP at peak exercise) was significantly higher in patients with coronary stenoses than in those without. Analysis of the relative cumulative frequency revealed that a SBP ratio greater than 0.87 was associated with significant stenoses. The sensitivity, specificity, and accuracy of ST change combined with a SBP ratio greater than 0.87 for detecting stenoses in patients with DM were 68%, 82%, and 74%, respectively. These results suggest that calculating the SBP ratio, in combination with monitoring for ST depression, improves the accuracy of treadmill exercise testing for the detection of CAD in patients with DM.

Adult↗

L-DOPA cyclohexyl ester is a novel potent and relatively stable competitive antagonist against L-DOPA among several L-DOPA ester compounds.

We explored L-DOPA esters with chemically bulky structures to find a potent stable competitive antagonist against L-DOPA, compared to DOPA methyl ester (DOPA ME). In anesthetized rats, DOPA cyclohexyl ester (DOPA CHE), DOPA cyclopentyl ester (DOPA CPE) and DOPA cyclopentyldimethyl ester (DOPA CPDME) at 1 microgram microinjected into depressor sites of the nucleus tractus solitarii elicited or tended to elicit more marked antagonism against depressor responses to 60 ng L-DOPA, compared to DOPA ME. At 100 ng, DOPA CHE elicited the most potent antagonism. At 1 microgram, duration of the antagonistic activity of DOPA CHE was approximately three times longer than that of DOPA ME. During microdialysis of the nucleus accumbens, conversion from DOPA CHE at 1 microM perfused via probes to extracellular L-DOPA was the lowest among these compounds and less than one half of that from DOPA ME. Binding studies showed that the recognition site for L-DOPA differs from ionotropic glutamatergic, dopaminergic D1 and D2 receptors. We recently found that L-DOPA evoked by transient ischemia may act as a DOPA CHE-sensitive causal factor for glutamate release and resultant neuronal cell death. DOPA CHE is the most potent, relatively stable competitive antagonist against L-DOPA and is a useful mother compound to develop neuroprotective drugs.

Animals↗

Accumulated lipids, aberrant fatty acid composition and defective cholesterol ester hydrolase activity in cholesterol ester storage disease.

We confirmed accumulation of glycogen and lipids, particularly cholesterol esters, in the liver of a patient with cholesterol ester storage disease (CESD). Hepatic cholesterol ester concentration was 100-200 times that found in normal livers. Analysis of the fatty acid composition indicated a higher proportion (41%) of cholesterol linoleate (C18-2), a slightly lower proportion (33%) of cholesterol oleate (C18-1) and normal proportions (14%) of cholesterol palmitate (C16-0) in the CESD patient compared with the control. This fatty acid composition of cholesterol esters and the fatty acid composition of other classes of lipids in the patient's liver resembled that of LDL. We also found that acid cholesterol ester hydrolase activity in the CESD liver was reduced to 5% of that in the control liver, while neutral cholesterol ester hydrolase activity remained at the control level. These results suggest that accumulated cholesterol esters were derived mainly from serum LDL and that the accumulation resulted from lack of acid cholesterol ester hydrolase.

Child, Preschool↗

Factors affecting attitudes towards mother-to-child transmission of HIV among pregnant women in a maternal and child hospital in Thailand.

This study determines the factors which correlate with attitudes towards mother-to-child transmission of HIV in pregnant women. Using a structured questionnaire, 527 pregnant women who visited a hospital to have prenatal checkups were interviewed. The survey items were: sociodemographic characteristics, experiences of pre-test counselling, knowledge of mother-to-child transmission, and attitude towards termination of pregnancy. Results showed that many pregnant women (80%) did not have proper knowledge of the possibility of mother-to-child transmission. Logistic regression analysis also indicates that age and knowledge of the possibility of mother-to-child transmission were the significant determinants of attitudes towards termination of pregnancy. Older women who believe that all the babies of pregnant women with HIV will be infected are most likely to terminate their pregnancy when they are diagnosed as HIV positive. Considering the importance of informed decisions regarding pregnancy, this study must have important implications for future support programmes for HIV-positive pregnant women.

Adolescent↗

Identification of a taurine transport inhibitory substance in sesame seeds.

An ethanol extract from sesame seeds inhibited the taurine uptake in human intestinal epithelial Caco-2 cells. The uptake of such alpha-amino acids as leucine and glutamic acid was not inhibited by the extract, indicating that this inhibition is specific to the taurine uptake. The unknown inhibitor in the sesame extract was purifled by reversed-phase HPLC by monitoring the inhibitory effect on taurine uptake. The isolated substance was identified as lysophosphatidylcholine, linoleoyl (Lyso-PC), by NMR and MS analysis. Lyso-PC inhibited the taurine uptake in a dose-dependent manner with an IC50 value of approximately 200 microM. Although Lyso-PC is known to be a surface active and cell lytic compound, neither damage nor loss of integrity of the Caco2 cell monolayer was apparent after treating with 200 microM Lyso-PC. Inhibition was observed by incubating cells with Lyso-PC for only 1 min prior to the uptake experiments. These results suggest the direct effect of Lyso-PC on the cell membrane to be the main mechanism for this inhibition. Lyso-PC may play a role in the regulation of certain intestinal transporters.

Biological Transport, Active↗

Characteristics of the biotin enhancement of glucose-induced insulin release in pancreatic islets of the rat.

Perifused isolated rat islets were used to show that biotin plus 16.5 mM glucose evoked more insulin secretion than 16.5 mM glucose alone. Whether or not this reinforcement of glucose-induced insulin secretion by biotin is unique was studied by using perifused islets stimulated with 16.5 mM glucose plus 100 microM of one of various components of the vitamin B group. No effect of any of these vitamins was found on glucose-induced insulin secretion. These results indicate that biotin is unique among the members of the vitamin B group in enhancing glucose-induced insulin secretion. Static incubation experiments showed that biotin did not potentiate insulin release when the islets were incubated with an experimental solution containing either no or 2.8 mM glucose. The addition of biotin to 27.7 mM glucose, which is the maximal concentration for stimulating insulin release, did not significantly enhance the effect of the glucose on insulin release (although it did at 16.5 mM glucose). These findings indicate that biotin, by itself, does not stimulate insulin secretion, and does not enhance glucose-induced insulin secretion beyond the ability of glucose itself to stimulate insulin secretion.

Animals↗

Regression of prostatic hypertrophy by osaterone acetate in dogs.

The prostatic regression effect of oral administration of a new steroidal anti-androgen, osaterone acetate, was investigated in dogs with prostatic hypertrophy. To dogs with prostatic hypertrophy, 0.1-1.0 mg/kg of osaterone acetate was orally administered for one week, and the regression rate was observed. It was shown that administration of osaterone acetate at 0.2 mg/kg or higher, sharply regressed prostatic hypertrophy during the early stage. Therefore, this agent may be clinically applicable as a therapeutic agent for benign prostatic hypertrophy.

Administration, Oral↗

Identical twins with long QT syndrome associated with a missense mutation in the S4 region of the HERG.

Familial long QT syndrome (LQTS) is caused by mutations in genes encoding ion channels important in determining ventricular repolarization. Mutations in at least five genes have been associated with the LQTS. Fire genes, KCNQ1, HERG, SCN5A, KCNE1, and KCNE2, have been identified. We have identified a missense mutation in the HERG gene in identical twins in a Japanese family with LQTS. The identical twins in our study had QT prolongation and the same missense mutation. However only the proband had a history of syncope. Although many mutations in LQT genes have been reported, there are few reports of twins with LQTS. This is the first report, to our knowledge, of identical twins with a HERG gene mutation.

Adult↗