Showing papers by "Kyushu University published in 1993"

Altered growth of human colon cancer cell lines disrupted at activated Ki-ras

Abstract: Point mutations that activate the Ki-ras proto-oncogene are presented in about 50 percent of human colorectal tumors. To study the functional significance of these mutations, the activated Ki-ras genes in two human colon carcinoma cell lines, DLD-1 and HCT 116, were disrupted by homologous recombination. Compared with parental cells, cells disrupted at the activated Ki-ras gene were morphologically altered, lost the capacity for anchorage-independent growth, grew more slowly both in vitro and in nude mice, and showed reduced expression of c-myc. Thus, the activated Ki-ras gene plays a key role in colorectal tumorigenesis through altered cell differentiation and cell growth.

Evidence of Impaired Endothelium-Dependent Coronary Vasodilatation in Patients with Angina Pectoris and Normal Coronary Angiograms

Abstract: Background A group of patients has been described who have chest pain resembling angina and positive exercise tests, but normal coronary angiograms and no coronary-artery spasm. This constellation of features has sometimes been called syndrome X or microvascular angina. We attempted to determine whether endothelium-dependent vasodilatation of the coronary vasculature was impaired in patients with this syndrome. Methods We infused the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilators papaverine and isosorbide dinitrate into the left coronary artery of 9 patients and 10 control subjects. The diameter of the left anterior descending coronary artery was assessed by quantitative angiography, and changes in coronary blood flow were estimated with the use of an intracoronary Doppler catheter. Results Acetylcholine, given in doses of 1, 3, 10, and 30 μg per minute, increased coronary blood flow in a dose-dependent manner in both groups. However, the mean (±SD) acetylchol...

How sensitive is PCR‐SSCP?

Abstract: Single-strand conformation polymorphism analysis (SSCP) is a rapid method for detection of minor sequence changes in polymerase chain reaction-amplified DNA Since the first reported use of SSCP in 1989 (Orita et al, 1989), this technique has been used widely to detect mutations in oncogenes, tumor suppressor genes, and genes responsible for genetic diseases Published mutations that have been detected using this technique include base substitutions, small insertions and deletions, and rearrangements This technique has also been applied for the detection of DNA polymorphisms at various loci of the human genome (reviewed by Hayashi, 1991; Hayashi, 1993) However, many factors can influence the sensitivity of SSCP, and its optimization is highly empirical In this review, we estimate the percentage of mutations that can be detected by this technique under various controlled conditions, and describe some critical elements affecting sensitivity

A simple method for estimating 24 h urinary sodium and potassium excretion from second morning voiding urine specimen in adults.

Abstract: SUMMARY 1 An assessment was made of the extent sodium (Na) and potassium (K) intake can be estimated from Na, K and creatinine (Cr) content of a second morning voiding urine (SMU) specimen collected within 4 h after the first voiding upon awakening but before breakfast in 159 clinically healthy, free-living individuals (20–79 years) The SMU and the rest of 24 h urine specimens for a 3–5 day period were collected 2 The following equations for estimating 24 h urinary Na (24HUNaV) and K (24HUKV) excretions were developed, and the accuracy and the reliability of these equations were evaluated Estimated value of 24HUNaV (mEq/day) = 163 √XNa; estimated value of 24HUKV (mEq/day) = 72 √XK, where XNa (or XK) = SMUNa (or SMUK)/SMUCr X predicted 24 h urinary Cr excretion 3 Highly statistically significant correlations were detected between the values estimated and measured for both Na (r= 0728, P < 0001, n= 159) and K (r= 0780, P < 0001, n= 159) 4 These equations were applied to Group 1 subjects, who collected the urine for a single day, and to Group 2, for 3 days The correlation coefficients between the values estimated and measured for Na and K were 0531 and 0443 in Group 1, and 0821 and 0590 in Group 2, respectively No statistically significant differences were observed 5 The SMU specimens provide a satisfactory alternative to both 24HUNaV and 24HUKV in adults for extensive epidemiological surveys but also for clinical application

Effects of age on endothelium-dependent vasodilation of resistance coronary artery by acetylcholine in humans.

Abstract: BACKGROUNDIt has been suggested that endothelium-related vasomotion is important in the control of coronary circulation. Our goal was to determine if endothelium-dependent dilation of the coronary vasculature was altered with aging in 18 patients with atypical chest pain (age, 23-70 years) who had angiographically normal coronary arteries and no coronary risk factors.METHODS AND RESULTSWe infused an endothelium-dependent vasodilator acetylcholine (1, 3, 10, and 30 micrograms/min) and an endothelium-independent vasodilator papaverine (10 mg) into the left coronary artery. The large coronary diameter was assessed by arteriography, and the increase in coronary blood flow was measured using the intracoronary Doppler catheter technique. Acetylcholine increased coronary blood flow in a dose-dependent manner with no changes in arterial pressure and heart rate. The maximum increase in coronary blood flow evoked by acetylcholine varied widely among patients (increase in coronary blood flow ranged from 200% to 560%...

Impaired coronary blood flow response to acetylcholine in patients with coronary risk factors and proximal atherosclerotic lesions.

Abstract: We examined whether coronary risk factors and atherosclerotic lesions in the study artery were associated with impaired endothelium-dependent dilation of coronary resistance arteries. Acetylcholine (ACH) at graded doses (1, 3, 10 and 30 micrograms/min) and papaverine (10 mg) were selectively infused into the left anterior descending coronary artery of 28 patients, in whom the study artery was angiographically normal (n = 16) or with mild stenosis or = 50 yr (P < 0.01) and total number of coronary risk factors (r = -0.62, P < 0.001) were associated with the impaired increase in CBF with ACH by univariate analysis. The percent increase in CBF evoked with papaverine did not correlate with these risk factors. The results suggest that mild atherosclerotic lesions in the study artery and coronary risk factors are accompanied by impaired endothelium-dependent dilation of coronary resistance arteries evoked with ACH. Endothelial dysfunction of coronary resistance arteries may result in altered regulation of myocardial perfusion in patients with mild coronary atherosclerosis and coronary risk factors.

Modeling of the deformation of a liquid droplet impinging upon a flat surface

Abstract: This article presents a theoretical study of the deformation of a spherical liquid droplet impinging upon a flat surface. The study accounts for the presence of surface tension during the spreading process. The theoretical model is solved numerically utilizing deforming finite elements and grid generation to simulate accurately the large deformations, as well as the domain nonuniformities characteristic of the spreading process. The results document the effects of impact velocity, droplet diameter, surface tension, and material properties on the fluid dynamics of the deforming droplet. Two liquids with markedly different thermophysical properties, water and liquid tin, are utilized in the numerical simulations because of their relevance in the industrial processes of spray cooling and spray deposition, respectively. The occurrence of droplet recoiling and mass accumulation around the splat periphery are standout features of the numerical simulations and yield a nonmonotonic dependence of the maximum splat radius on time.

Inhibition of nitric oxide formation in the nucleus tractus solitarius increases renal sympathetic nerve activity in rabbits.

Abstract: It has been shown that nitric oxide (NO) is synthesized in the central nervous system as well as in vascular endothelial cells. However, the physiological role of NO in cardiovascular regulation by the central nervous system remains unclear. This objective of this study was to examine the possibility that NO plays a role in neural transmission in the nucleus tractus solitarius (NTS) and thus contributes to control of sympathetic nerve activity in rabbits. We examined the effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO from L-arginine, microinjected into the NTS on arterial pressure (AP), heart rate (HR), and renal sympathetic nerve activity (RSNA). L-NMMA increased AP and RSNA in rabbits with intact as well as denervated sinoaortic baroreceptors and vagi. L-NMMA increased HR only in rabbits with sinoaortic denervation and vagotomy. Pretreatment with L-arginine microinjected into the NTS, which did not alter baseline AP, HR, and RSNA, prevented the increases in AP and RSNA evoked with subsequent L-NMMA. Pretreatment with D-arginine did not alter the effects of subsequent L-NMMA injections into the NTS. The gain of arterial baroreflex control of RSNA assessed by the slope of the regression line relating changes in AP and those in RSNA caused by intravenous phenylephrine or nitroglycerin did not differ before and after microinjections of L-NMMA. L-NMMA microinjected into the area postrema did not alter AP, HR, or RSNA. These results suggest that in rabbits NO is involved in the mechanism in the NTS that mediates tonic inhibition of RSNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Papillary cystic tumors of the pancreas. Assessment of their malignant potential.

Abstract: Background. Although the biologic characteristics of papillary cystic tumors (PCT) generally indicate a good prognosis, a malignant form has been reported. Methods. Twenty-two examples of PCT were examined to assess their malignant potential by histologic, flow cytometric, and immunohistochemical studies. Results. Three had hepatic, peritoneal, and/or lymph node metastases (metastasizing tumors [MT]); the other 19 PCT had no such metastatic features (nonmetastasizing tumors [NMT]). Venous invasion was detected in all three MT and two NMT. Compared with the 19 NMT, the MT had a higher nuclear grade and more prominent necrobiotic nests characterized by aggregates of cells with pyknotic nuclei and eosinophilic cytoplasm. In the flow cytometric analysis of cellular DNA content, one MT was aneuploid, and eight NMT were diploid. Immunohistochemically, there was no difference between the MT and NMT. Conclusions. These results support the assumption that venous invasion, nuclear grade, and prominent necrobiotic nests are useful as histologic parameters to detect the malignant potential of PCT. Cancer 1993; 71:82-92.

Evaluation of the risk of instrumentation as a foreign body in spinal tuberculosis. Clinical and biologic study.

Abstract: The risk of persistence and recurrence of infection in posterior spinal instrumentation surgery for spinal tuberculosis was studied clinically and microbiologically. Eleven patients with thoracic, thoracolumbar, and lumbar spinal tuberculosis treated by debridement, anterior fusion, and combined posterior instrumentation surgery were analyzed. Seven patients had tuberculosis in both anterior and posterior spinal elements. There were no cases of persistence or recurrence of infection after surgery, and instrumentation provided immediate stability and protected against development of kyphotic deformity. The adherence properties of Mycobacterium tuberculosis to stainless steel (SUS 316) was evaluated experimentally. The results showed that posterior instrumentation surgery was not a hazard to spinal tuberculosis infection when combined with radical debridement and intensive anti-tuberculosis chemotherapy.

Thermal conductivity of a polymer composite

Abstract: A prediction equation for thermal conductivity of polymer composites reported in our previous papers has been revised in terms of two view points: (1) estimation of thermal conductivity of a composite using an idea of reduced thermal conductivity; and (2) the effect of ease in forming conductive filler chains on thermal conductivity is related to the CVF value in electric conductivity of the composite. The new equation was confirmed to be adaptable to thermal conductivities of varieties of polymer composite systems filled with spherical or irregular fillers. The equation was also considered to explain thermal conductivity of polymer composites filled with fibers. Further, it was found that thermal conductivities of fiber composites can be estimated by introducing a factor of the CVF value or aspect ratio (L/D) into the new equation. © 1993 John Wiley & Sons, Inc.

Molecular cloning of a human cDNA encoding a novel protein, DAD1, whose defect causes apoptotic cell death in hamster BHK21 cells.

Abstract: The tsBN7 cell line, one of the mutant lines temperature sensitive for growth which have been isolated from the BHK21 cell line, was found to die by apoptosis following a shift to the nonpermissive temperature. The induced apoptosis was inhibited by a protein synthesis inhibitor, cycloheximide, but not by the bcl-2-encoded protein. By DNA-mediated gene transfer, we cloned a cDNA that complements the tsBN7 mutation. It encodes a novel hydrophobic protein, designated DAD1, which is well conserved (100% identical amino acids between humans and hamsters). By comparing the base sequences of the parental BHK21 and tsBN7 DAD1 cDNAs, we found that the DAD1-encoding gene is mutated in tsBN7 cells. The DAD1 protein disappeared in tsBN7 cells following a shift to the nonpermissive temperature, suggesting that loss of the DAD1 protein triggers apoptosis.

Activation of CYP11A and CYP11B gene promoters by the steroidogenic cell-specific transcription factor, Ad4BP.

Abstract: We have examined the transcriptional activity of four cis-elements, Ad1(CRE), Ad2, Ad3, and Ad4, that are present in the promoter of the bovine CYP11B (11 beta-hydroxylase P-450) gene using beta-globin reporter gene constructs and transient transfection into steroidogenic and nonsteroidogenic cell types. Only Ad1(CRE), a CRE homolog, showed forskolin-dependent transcriptional activity in adrenal tumor Y-1 cells, whereas the other elements were not able to stimulate transcription by themselves. As Ad3 and Ad4 had previously been identified as the cis-elements required for full cAMP-dependent transcription of this gene, we examined the effect of combinations of different cis-elements on the transcription of the reporter gene. In Y-1 cells, Ad1(CRE) and four tandem copies of any one of the other cis-elements substantially activated transcription in response to forskolin treatment. The template carrying Ad1(CRE) and Ad4 was also active in testicular Leydig cells, I-10, whereas it was inactive in nonsteroidoge...

Propofol Activates GABAA Receptor-Chloride Ionophore Complex in Dissociated Hippocampal Pyramidal Neurons of the Rat

Abstract: BackgroundThe molecular mechanism of propofol anesthesia has been related to facilitation of the inhibitory neu-rotransmission mediated by γ-aminobutyric acid (GABA). In the current study, the authors examined the direct actions of propofol on the acutely dissociated mammalian central neurons.Method

Use of ESR for deterioration diagnosis of electrolytic capacitor

Abstract: A new deterioration diagnosis method for the electrolytic capacitor is proposed for a forward-type converter and a buck-boost converter. It was observed that the ESR (equivalent series resistance) of the electrolytic capacitor increases as it deteriorates, and the knowledge that ripple varies proportionally to the ESR increase was used. With this method, the electrolytic capacitor life-cycle aging rate can be projected for the active circuit over the system life. This approach to deterioration is valid for any load condition, no matter whether the circuit has feedback control or not. >

Inhibition of Angiotensin I-converting Enzyme by Bacillus licheniformis Alkaline Protease Hydrolyzates Derived from Sardine Muscle

Abstract: Hydrolyzates which inhibit the angiotensin I-converting enzyme (ACE) were prepared from sardine muscle by Bacillus licheniformis alkaline protease. Considering the practical application of preparations as a functional food material, the best proteolytic conditions with respect to taste, solubility and ACE inhibitory activity were a 0.3 wt% addition of the enzyme and 17-h proteolysis at 50°C and pH 9.0. The preparations under these conditions had potent activity (IC50=0.26 mg protein/ml). Fractionation of the preparations on an ODS column with ethanol resulted in the production of more potent inhibitors. The most potent activity was obtained when eluting with 10% ethanol (IC50=0.015 mg protein/ml). This fraction was apparently rich in acidic amino acids, poor in hydrophobic ones, and effective for use as a physiologically functional food material by virtue of little bitterness, a fish odor and powerful ACE inhibitory activity.

Hepatoid Adenocarcinoma of the Stomach A Clinicopathologic and Immunohistochemical Analysis

Abstract: Background. The clinicopathologic and immunohistochemical features of the primary gastric hepatoid adenocarcinomas still remain unclear. Methods. The authors evaluated 28 hepatoid adenocarcinomas (HC) of the stomach on the basis of characteristic histologic features resembling hepatocellular carcinoma, which were selected from the 7200 cases of primary gastric carcinoma in their files. Additionally, 22 alpha-fetoprotein (AFP)-positive adenocarcinomas without hepatoid features (APC) were also selected. Results. The HC cases fell into the following two groups: HC with AFP-positive tumor cells (Group 1; 15 cases) and HC without AFP-positive cells (Group 2; 13 cases). Histologically, the glycogen granules and hyaline globules were common features in HC. The incidence of a venous invasion of HC (Groups 1 and 2) was higher than that of APC (Group 3). There were no significant differences among the three groups regarding clinical features, macroscopic features, and the incidence of lymphatic permeation. An immunohistochemical study showed that HC had differentiation into various directions. As for the advanced carcinomas, the 5-year survival rates of patients with HC (Groups 1 and 2) and those with APC (Group 3) were 11.9% (21.4%, 8.3%) and 38.2%, respectively. The prognosis of Group 1 was similar to that of Group 2, but was poorer than that of Group 3. Conclusions. The findings suggested that HC, as shown by its characteristic histologic features, had a poor prognosis whether producing AFP or not, and that HC should therefore be distinguished from AFP-positive carcinoma without hepatoid features.

Turbulence structure and mass transfer across a sheared air–water interface in wind-driven turbulence

Abstract: The mass transfer mechanism across a sheared air–water interface without bubble entrainment due to wave breaking was experimentally investigated in terms of the turbulence structure of the organized motions in the interfacial region in a wind-wave tank. The transfer velocity of the carbon dioxide (CO2) on the water side was measured through reaeration experiments of CO2, and the fluid velocities in the air and water flows were measured using both a hot-wire anemometer and a laser-Doppler velocimeter. The results show that the mass transfer across a sheared air–water interface is more intensively promoted in wind shear, compared to an unsheared interface. However, the effect of the wind shear on the mass transfer tends to saturate in the high-shear region in the present wind-wave tank, where the increasing rate of mass transfer velocity with the wind shear decreases rapidly. The effect of the wind shear on the mass transfer can be well explained on the basis of the turbulence structure near the air–water interface. That is, surface-renewal eddies are induced on the water side through the high wind shear on the air–water interface by the strong organized motion generated in the air flow above the interface, and the renewal eddies control the mass transfer across a sheared interface. The mass transfer velocity is correlated with the frequency of the appearance of the surface-renewal eddies, as it is in open-channel flows with unsheared interfaces, and it increases approximately in proportion to the root of the surface-renewal frequency. The surface-renewal frequency increases with increasing the wind shear, but for high shear the rate of increase slows. This results in the saturated effect of the wind shear on the mass transfer in the high-shear region in the present wind-wave tank. The mass transfer velocity can be well estimated by the surface-renewal eddy-cell model based on the concept of the time fraction when the surface renewal occurs.

An investigation of ductility and microstructural evolution in an Al−3% Mg alloy with submicron grain size

Abstract: A submicrometer-grained (SMG) Al−3% Mg solid solution alloy, with an initial grain size of ∼0.2 μm, was produced by intense plastic straining. Experiments show that tensile specimens of the SMG alloy exhibit high elongations to failure at low testing strain rates at the relatively low temperature of 403 K. The stress exponent is high (∼7–8) and calculations show deformation is within the region of power-law breakdown. The initial microstructure of the alloy consists of diffuse boundaries between highly deformed grains. At strain rates of ∼10−4 s−1 and lower, plastic deformation leads to dynamic recrystallization and the formation of highly nonequilibrium grain boundaries that gradually evolve into a more equilibrated configuration.

Prevalence of type 2 (non-insulin-dependent) diabetes mellitus and impaired glucose tolerance in the Japanese general population: the Hisayama Study.

Abstract: We determined the population-based prevalence of diabetes mellitus in members of the Japanese community, Hisayama aged 40–79 years old by a 75-g oral glucose tolerance test. The basic population used to calculate diabetic prevalence was 1,077 men (72.8% of the whole population in the same age range) and 1,413 women (80.8%) including ten diabetic patients on insulin therapy. In addition, we compared the prevalence of history of diabetes which was acquired by interview or questionnaire, between participants and non-participants in the 75-g oral glucose tolerance test, but they were not statistically different. The age-adjusted prevalence of diabetes to world population was 12.7% for men and 8.4% for women, and that of impaired glucose tolerance was 19.6% for men and 18.4% for women. These figures were much higher than those previously reported from several Japanese communities. The results obtained from the present study could reveal true prevalence of diabetes among the Japanese population. In addition, the reasons for the increasing prevalence of diabetes among the recent Japanese population are also discussed.

Restriction landmark genomic scanning method and its various applications

Abstract: We have developed a new genome scanning method (restriction landmark genomic scanning (RLGS)), based on the new concept of using restriction enzyme sites as landmarks. RLGS employs direct end labeling of the genomic DNA digested with a restriction enzyme and two-dimensional electrophoresis with high-resolution. Its advantages are: (i) high-speed scanning ability, allowing simultaneous scanning of thousands of restriction landmarks; (ii) extension of the scanning field using different kinds of landmarks in an additional series of electrophoresis; (iii) application to any type of organism because of direct-labeling of restriction enzyme sites and no hybridization procedure; and (iv) reflection of the copy number of the restriction landmark by the spot intensity which enables distinction of haploid and diploid genomic DNAs. The RLGS method has various applications because it can be used to scan for physical genomic DNA states, such as amplification, deletion and methylation. The copy number of the locus of a restriction landmark can be estimated by the spot intensity to find either an amplified or deleted region. The methylation state of genomic DNA can also be discovered by use of a methylation-sensitive restriction enzyme sites as a restriction landmark (restriction landmark genomic scanning for screening methylated sites, RLGS-M). This article introduces the basic principle of RLGS and its applications to the analysis of cancer, mouse mutant DNAs and tissue-specific methylation, showing the usefulness of RLGS for a variety of biological fields.

Importance of the Proline-Rich Region Following Signal-Anchor Sequence in the Formation of Correct Conformation of Microsomal Cytochrome P-450s

Abstract: A proline-rich region is present following the signal-anchor sequence in the amino-terminal portion of all known microsomal cytochrome P-450s. To assess the functional significance of the proline residues in this region, we systematically altered these residues of cytochrome P450(M1) (P450 2C11); one, two, and three proline residues out of the five in the region were exchanged for alanine residues. The wild-type and the mutated proteins were expressed in the fission yeast Schizosaccharomyces pombe under the control of nmt1 promoter. The wild-type and the mutated proteins were all highly expressed in the yeast cells (5-9% of the total membrane protein). The expressed wild-type P450(M1) showed a typical carbon monoxide difference spectrum of P-450 and the activity of testosterone hydroxylation, whereas all the mutated proteins constructed in the present study showed no characteristic P-450 spectrum, suggesting that the substitution of the proline residues in this region resulted in a defect of proper heme incorporation. Furthermore, the mutated proteins in which more than one proline residues had been exchanged were more sensitive to trypsin digestion than the wild type. From these results, we propose that the proline residues in the proline-rich region are crucial for the formation of the correct conformation of microsomal P-450 molecules.

Kinetic analysis of two types of Na+ channels in rat dorsal root ganglia.

Abstract: 1. The gating properties of two types of Na+ channels were studied in neurones isolated from rat dorsal root ganglia using the whole cell variation of the patch electrode voltage-clamp technique. 2. Two types of Na+ currents (INa) were identified on the basis of their sensitivity to tetrodotoxin (TTX). One type was insensitive to TTX (up to 0.1 mM), while the other type was blocked by 1 nM of TTX. Whereas they were both insensitive to 50 microM Cd2+, a high concentration (2 mM) of Co2+ selectively inhibited the TTX-insensitive type. 3. The activation thresholds were about -60 and -40 mV for the TTX-sensitive and the TTX-insensitive INa, respectively. Activation of the TTX-sensitive INa developed with a sigmoidal time course which was described by m3 kinetics, whereas the activation of the TTX-insensitive INa was described by a single exponential function. A deactivation process, as measured by the tail current upon repolarization, followed an exponential decay in either type of INa. 4. The rate constant of activation indicated that under comparable membrane potential conditions, the TTX-insensitive channels open 4-5 times slower than the TTX-sensitive ones upon depolarization. Likewise, the rate constant of inactivation indicated that the TTX-insensitive channels inactivate 3-7 times more slowly than the TTX-sensitive ones upon repolarization. 5. The steady-state activation curve for the TTX-insensitive INa was shifted about 20 mV in the positive direction from that for the TTX-sensitive INa. 6. The steady-state inactivation curve for the TTX-insensitive INa as obtained with a 0.5 s prepulse was shifted about 26 mV in the positive direction from that for the TTX-sensitive INa, indicating a greater availability for the TTX-insensitive INa in depolarized membrane. However, on increasing the duration of prepulse, the inactivation curve for the TTX-insensitive INa, but not for the TTX-sensitive INa, shifted in the negative direction due to an extremely slow inactivation process in the TTX-insensitive INa. Consequently, an overlap between the activation and inactivation curves which causes a steady influx of Na+ (window current) became progressively reduce. 7. The time course of INa decay was best described by a single exponential process in either the TTX-sensitive or TTX-insensitive INa, whereas the development of inactivation and the recovery from inactivation, which were measured by a conventional double-pulse protocol, followed a second order process in either channel type.(ABSTRACT TRUNCATED AT 400 WORDS)