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Biomedical subjects

M Ishihara

Publications and source records attributed to M Ishihara.

At least 73 records · Page 4Linked to original sources
PubMed2000

Measurement of human plasma phospholipid transfer protein by sandwich ELISA.

BACKGROUND: Plasma phospholipid transfer protein (PLTP) plays a central role in the remodeling of HDLs. Reliable and accurate methods for assaying PLTP concentration are required. METHODS: A sandwich ELISA for PLTP has been developed, using two monoclonal antibodies against recombinant human PLTP (rhPLTP) expressed in Chinese hamster ovary cells. The ELISA allows for the quantification of PLTP in the range 0.625-15.0 ng/assay (1.2-30.0 mg/L). Intra- and interassay CVs were <3.0% and <4.2% respectively. The assay was used to quantify plasma PLTP concentrations in 132 Japanese subjects (75 males and 57 females). RESULTS: PLTP concentrations were 12.0 +/- 3. 0 mg/L (mean +/- SD; range, 4.9-20.5 mg/L). No sex difference was observed. Plasma PLTP concentration was positively correlated with HDL-cholesterol (r = 0.72; P: <0.001), apolipoprotein (apo) A-I (r = 0.62; P: <0.001) and HDL(2)-cholesterol (r = 0.72; P: <0.001), and was negatively correlated with triacylglycerol (r = -0.45; P: <0. 001). There was no correlation with plasma apo A-II. These results agree with other evidence that plasma PLTP is associated with large apo A-I-containing lipoproteins. There was no correlation (r = -0. 01) between plasma PLTP and plasma phosphatidylcholine transfer activity (range, 3.5-10.5 micromol. mL(-1). h(-1)), suggesting that PLTP may exist in active and inactive forms. CONCLUSION: This new ELISA will be of value for further studies of PLTP in health and disease.

Adult↗
PubMed2000

Radical generation, radical-scavenging activity, and cytotoxicity of eugenol-related compounds.

To clarify the possible link between radicals and cytotoxicity of eugenol-related compounds, dimeric compounds were synthesized from eugenol (4-allyl-2-methoxy-phenol), butylated hydroxyanisole (BHA) (2-t-butyl-4-methoxyphenol) or MMP (2 methoxy-4-methylphenol); bis-EUG (3,3'-dimethoxy-5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol), bis-BHA (3,3'-di-t-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diol), and bis-MMP (3,3'-di-methoxy-5,5'-dimethyl-1,1'-biphenyl-2,2'-diol). The cytotoxic activity of these compounds was determined using a salivary gland tumor cell line (HSG), oral squamous cell carcinoma cell line (HSC-2) and human promyelocytic leukemia cell line (HL-60). A parabolic relationship between the cytotoxicity and log P (the octanol-water partition coefficient) was observed, showing that both BHA and bis-MMP, with a log P of 3-4, were the most cytotoxic. The cytotoxic activity of the 2-methoxy derivatives, eugenol, MMP and bis-MMP, against HSG cells was significantly enhanced by visible-light irradiation, possibly due to their high redox potential. Electron spin resonance (ESR) spectroscopy indicated that eugenol and BHA alone produced radicals under alkaline conditions (pH > 9.5), and eugenol most efficiently scavenges reactive oxygen species (O2-). Antioxidative reactivity of eugenol-related compounds was determined by measuring the inhibiting periods of the AIBN (2,2'-azobisisobutyronitrile)/MMA (methyl methacrylate) polymerization system, and the number of moles of peroxy radical trapped by moles of the relevant phenols (stoichiometric factor, n). It was found that the n values of eugenol and MMP were approximately 1, whereas those of BHA >2, suggesting that eugenol and MMP undergo dimerization through radical-radical couplings through quinone methides, whereas BHA undergoes the competitive interaction with poly-MMA radicals after oxidation by AIBN-peroxy radicals. BHA was an efficient peroxy radical-scavenger, but possibly reacted with polymer radicals of the lipid, thus mediating the cytotoxicity. The n value of bis-BHA was two, whereas those of bis-EUG and bis-MMP were 1.6-1.7, suggesting that the latter were further oxidized. The enthalpies of phenoxyl radical formation were determined using the semi-empirical PM3 quantum-mechanical method and the possible link to redox potential was discussed.

Adenocarcinoma↗
PubMed1999

Expression of a chitinase gene and lysis of the host cell wall during Chlorella virus CVK2 infection.

A chitinase gene (vChti-1) encoded by the Chlorella virus CVK2 was cloned and characterized. The vChti-1 open reading frame consisted of 2508 bp corresponding to 836 amino acid residues. The predicted amino acid sequence contained two sets of a family 18 catalytic domain that is responsible for chitinase activity. Northern blot analysis revealed that the vChti-1 gene was expressed in virus-infected Chlorella cells late in infection, when a single transcript of about 2.5 kb appeared at 120 min postinfection. This result was confirmed by Western blotting with a specific anti-vChti-1 protein antibody; a protein of about 94 kDa was detected specifically beginning at 240 min postinfection and was present until cell lysis. The protein was not incorporated into viral particles but remained in the medium after cell lysis. The vChti-1 protein produced in virus-infected cells showed chitinase activity on zymogram assays.

Amino Acid Sequence↗
PubMed1999

Loss of transcription factor IRF-1 affects tumor susceptibility in mice carrying the Ha-ras transgene or nullizygosity for p53.

The transcription factor IRF-1 has been implicated in tumor suppression: IRF-1 suppresses cell transformation and mediates apoptosis in vitro. Here we show that the loss of IRF-1 alleles per se has no effect on spontaneous tumor development in the mouse but dramatically exacerbates previous tumor predispositions caused by the c-Ha-ras transgene or by nullizygosity for p53. Grossly altered tumor spectrum, as compared to p53-null mice, was also observed in mice lacking both IRF-1 and p53, and cells from these mice show significantly higher mutation rate. Our results suggest that IRF-1 is a new member of the tumor susceptibility genes.

Animals↗
PubMed1999

Long-term prognosis of late spontaneous reperfusion after failed thrombolysis for acute myocardial infarction.

BACKGROUND: Early reperfusion improves left ventricular (LV) function and survival after acute myocardial infarction (MI). Thrombolytic therapy achieves early patency of the infarct artery in about two-thirds of patients. In nearly half of the remaining patients, in whom early reperfusion was not achieved with thrombolytic therapy, the infarct artery might reopen by the time of predischarge angiography. However, the impact of such late spontaneous reperfusion after failed thrombolytic therapy on LV function and long-term survival remained unclear. HYPOTHESIS: This study was undertaken to assess implication of late spontaneous reperfusion after failed thrombolytic therapy on LV function and long-term survival after acute MI. METHODS: The study consisted of 198 patients with anterior acute MI who underwent thrombolytic therapy and predischarge angiography: 160 patients with infarct artery patent early and late after therapy (persistent patency), 17 patients with infarct artery occluded early after therapy but patent at predischarge angiography (late spontaneous reperfusion), and 21 patients with infarct artery occluded early and late after therapy (persistent occlusion). RESULTS: Persistent patency was associated with enhanced improvement in LV ejection fraction (7.7 +/- 11.8%) compared with late spontaneous reperfusion (0.0 +/- 9.6%, p = 0.03) and persistent occlusion (-1.4 +/- 9.7%, p = 0.003). Persistent patency was associated with better long-term survival than with late spontaneous reperfusion (p < 0.001) and persistent occlusion (p < 0.001). Multivariate analysis comparing persistent patency and late spontaneous reperfusion showed that early reperfusion was an independent predictor of long-term survival. CONCLUSION: Late spontaneous reperfusion after failed thrombolytic therapy was associated with poor LV function and long-term survival, emphasizing the importance of early reperfusion.

Aged↗
PubMed1999

Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies.

BACKGROUND/PURPOSE: This report describes the results of a group study of the Japanese Study Group of Anorectal Anomolies (JSGA) to determine the relative incidence of specific types of anorectal anomaly in Japan, and includes discussion of rectourethral fistula regarding the relationship between the levels of the fistula and blind end of the rectum, low type deformity, rare types, and associated anomalies. METHODS: A total of 1,992 patients (1,183 boys and 809 girls) registered from 1976 to 1995 were analyzed. RESULTS: High-type deformities accounted for 26.0% of cases, intermediate 10.7%, low 57.2%, miscellaneous 4.5% and unclassified 1.8%. The most frequent deformity was male anocutaneous fistula (n = 364), followed by male rectourethral fistula (n = 333), and female anovestibular fistula (n = 241). There were 42 rectovesical fistulas in boys and 93 rectocloacal fistulas in girls. Covered anus complete occurred at the same frequency (10.1% of low deformities) as covered anal stenosis. In rectourethral fistula, the blind end of the rectum lay at or above the level of the P-C line in 40.3% of cases, at or above the M line in 39.6% and at the vicinity of the I line in 20.2%, respectively. There was no parallel relationship between the site of the fistula opening and the level of the rectal pouch. The overall incidence of patients having one or more associated anomalies was 45.2%: 70.6% in high deformity, 60.7% in intermediate, and 31.3% in low. The rate of association of Down's syndrome with deformities without fistula (40.3%) was significantly higher than with deformities with fistula (0.3%). CONCLUSIONS: Rectovesical fistula and covered anus complete were not infrequent deformities in this series. We consider that at least 20% of rectourethral fistula should be categorized as intermediate or low deformity from the viewpoint of the position of the rectal pouch. A significant preponderance of Down's syndrome in the deformities without fistula suggests that further investigation of associated anomalies in comparision with other congenital diseases may provide insights into the pathogenesis of anorectal malformation in the field of molecular genetics.

Anal Canal↗
PubMed1999

Disintegration of uncooked rice by carboxymethyl cellulase from Sporotrichum sp. HG-I.

A thermostable carboxymethyl cellulase (CMCase) was purified to homogeneity from a wheat bran culture of the thermophilic fungus Sporotrichum sp. HG-1, an isolate from a compost heap. The enzyme had a molecular weight (M(r)) of 33,000 by SDS-PAGE. The optimum temperature and pH for enzyme activity were 70 degrees C and 4.5-5.0, and the enzyme was heat stable. Uncooked Thai rice was digested so as to cause its disintegration by the addition of purified CMCase, but not by the addition of xylanase purified from strain HG-1. Ferulic acid conjugated to oligosaccharide was released significantly by the combined action of CMCase and xylanase, but the free form of ferulic acid was not detectable.

Journal Article↗
PubMed1999

Sex ratio distortion and severe inbreeding depression in the gypsy moth Lymantria dispar L. in Hokkaido, Japan.

An abnormal female producing only female progeny was found in Lymantria dispar in Hokkaido, Japan, in July 1996. Similarly, its progeny produced only females. Egg hatch rates were near 50% in all-female matrilines. Therefore, a certain cytoplasmic factor was thought to kill males in eggs differentially, resulting in only female hosts. In the next generation, the field population was estimated to contain 9.1% abnormal females. Severe inbreeding depression was also observed in egg hatch rates during confirmation of maternal inheritance. The cost of inbreeding was estimated at 0. 395, which is one of the highest in insects. Inbreeding avoidance by their host has been cited as one of the advantages of a male-killing factor, but we suggest that this is not applicable in this moth.

Animals↗
PubMed1999

Structural features in heparin that interact with VEGF165 and modulate its biological activity.

The 165 amino acid form of vascular endothelial growth factor (VEGF165) is a heparin-binding growth factor with mitogenic activity for vascular endothelial cells. We examined activities of various heparin derivatives toward their interactions with VEGF165 using an enzyme-linked immunosorbent assay and elucidated the structural features in heparin for the interactions. Native heparin interacted with VEGF165, whereas N-desulfated, N-acetylated (N-DS, N-Ac-) heparin, and 6-O-desulfated (6-O-DS-) heparin did not. The 2-O-desulfated (2-O-DS-) heparin retained the ability for the interaction with VEGF165. In contrast, the 2-O-DS-heparin exhibited no ability for the interaction with FGF-2 and HGF. Thus, structural requirements in heparin for the specific interaction with VEGF165 are distinct from those with FGF-2 and HGF which require a high content of 2-O-sulfate groups. In a cell proliferation assay, native heparin and 2-O-DS-heparin exhibited inhibitory abilities for VEGF165-induced proliferation of human umbilical vein endothelial cells (HUVECs) with their high concentrations (more than 64 microg/ml), while only native heparin could enhance the proliferation of the chlorate-treated cells. These results suggested that a high content of 2-O-sulfate groups is not required for the specific interaction with VEGF165alone, although it is essential for the mitogenic activity of the growth factor.

Binding Sites↗
PubMed1999

Crossed cerebellar diaschisis: the role of motor and premotor areas in functional connections.

The authors assessed the relationship between crossed cerebellar diaschisis (CCD) and cortico-pontine cerebellar pathway (CPCP) damage in 29 chronic supratentorial infarct patients to elucidate the role of motor and premotor areas for functional cerebro-cerebellar connections. The CCD rate was calculated from side-to-side cerebellar count differences on 123I-IMP single-photon emission computerized tomography images. Neuronal damage was estimated by the three scores of computed tomography density from equal to normal brain tissue (score 0) to equal to cerebrospinal fluid (score 2) in the 4 major regions on CPCP; frontal association, motor and premotor, sensory and parietal associations, and the posterior limb of the internal capsule. Two-factor factorial ANOVA by the score and the region revealed significant differences of the CCD rate in the score factor (score 0 or 1 vs. score 2, p = < 0.05) and the independency of these two factors. Categories determined by the scores in each region were analyzed by multiple stepwise regression analysis using the theory of quantification I, in which significant correlation only between CCD and the necrotic density (score 2) in motor and premotor areas were demonstrated (r = 0.515, p = < 0.05). The authors conclude that neuronal loss in motor and premotor areas seem to contribute significantly to functional cerebro-cerebellar disconnections.

Adult↗
PubMed1999

Impeding O(2) unloading in muscle delays oxygen uptake response to exercise onset in humans.

We tested whether the leftward shift of the oxygen dissociation curve of hemoglobin with hyperpnea delays the oxygen uptake (VO(2)) response to the onset of exercise. Six male subjects performed cycle ergometer exercise at a work rate corresponding to 80% of the ventilatory threshold (VT) VO(2) of each individual after 3 min of 20-W cycling under eupnea [control (Con) trial]. A hyperpnea procedure (minute ventilation = 60 l/min) was undertaken for 2 min before and during 80% VT exercise in hypocapnia (Hypo) and normocapnia (Normo) trials. In the Normo trial, the inspired CO(2) fraction was 3% to prevent hypocapnia. The subjects completed two repetitions of each trial. To determine the kinetic variables of VO(2) and heart rate (HR) at the onset of exercise, a nonlinear least-squares fitting was applied to the data averaged from two repetitions by a monoexponential model. The end-tidal CO(2) partial pressure before the onset of exercise was significantly lower in the Hypo trial than in the Con and Normo trials (22 +/- 1 vs. 38 +/- 3 and 36 +/- 1 mmHg, respectively, P < 0.05). The time constant of VO(2) and HR was significantly longer in the Normo trial (28 +/- 7 and 39 +/- 18 s, respectively) than in the Con trial (21 +/- 7, 34 +/- 16 s, respectively, P < 0.05). The VO(2) time constant of the Hypo trial (37 +/- 12 s) was significantly longer than that of the Normo trial, although no significant difference in the HR time constant was seen (Hypo, 41 +/- 28 s). These findings suggested that respiratory alkalosis delayed the kinetics of oxygen diffusion in active muscle as a result of the leftward shift of the oxygen dissociation curve of hemoglobin. This supports an important role for hemoglobin-O(2) offloading in setting the VO(2) kinetics at exercise onset.

Adult↗
PubMed1999

Effects of various kinds of dietary amino acids on the hepatotoxic action of D-galactosamine in rats.

The protective effects of various kinds of dietary amino acids against the hepatotoxic action of D-galactosamine (GalN) were examined. Male Wistar rats fed with 20% casein diets containing 10% or 5% amino acid for one week were injected with GalN (800 mg/kg body weight), and the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities, the hepatic glycogen concentration, and the serum glucose-level were examined 20 hours after the injection. In the groups with the 10% amino acid diets, activities of AST, ALT, and LDH in serum of 10% L-glutamine (Gln), 10% L-asparagine (Asn), and 10% L-serine (Ser) groups were significantly lower than those of the control group, and in the groups with the 5% amino acid diets, those activities of 5% L-histidine (His), 5% L-tyrosine (Tyr), 5% L-lysine (Lys), and 5% L-glycine (Gly) groups were also lower than those of the control group. The concentration of liver glycogen of 10% Gln-, 10% Asn-, and 10% Ser- groups and those levels of 5% His-, 5% Tyr-, 5% Lys-, and 5% Gly-groups were also significantly higher than that of the control group. As a result, it was found that some kinds of dietary amino acid such as L-Ser, L-Asn, L-His, L-Lys, L-Tyr, and L-Gly, in addition to L-Gln were effective to protect the rats from GalN-induced injury.

Alanine Transaminase↗
PubMed1999

Effect of luminance contrast on the motion aftereffect.

The effects of luminance contrast and spatial frequency on the motion aftereffect were investigated. The point of subjective equality for velocity was measured as an index of the motion aftereffect. The largest effect was observed when a low contrast grating (5%) was presented as a test stimulus after adaptation to a high contrast grating (100%) in the low spatial frequency condition (0.8 cycle deg.-1). On the whole, the effect increased with increasing adapting contrast and with decreasing test contrast or spatial frequency. Small effects were observed at high test contrasts. These results were inconsistent with those of Keck, Palella, and Pantle in 1976. Analysis showed that there was no saturation on velocity of the motion aftereffect above 5% of the contrast although Keck, et al. (1976) found that the incremental increases of the effect above 3% adapting contrast were small.

Afterimage↗
PubMed1999

[Relationship between plasma hormones and ventricular premature contractions in extracorporeal shock wave lithotripsy--significance of human atrial natriuretic peptide (hANP)].

Extracorporeal shock wave lithotripsy (ESWL) is a safe and effective treatment for upper urinary tract stones. However, the mechanism by which this treatment may be involved in causing ventricular premature contractions (VPC) is unknown. We evaluated the relationship between VPC and plasma hormones in patients treated by ESWL. Holter monitoring was performed on 61 outpatients undergoing ESWL with electrocardiographic synchronization for upper urinary tract stones. The levels of cathecolamine, plasma renin activity (PRA), plasma aldosterone concentration (PAC), and human atrial natriuretic peptide (hANP) were measured before, immediately after, and 7 days after ESWL. Systolic blood pressure increased significantly immediately after, and decreased 7 days after ESWL. VPC occurred during 23 treatments (37.7%) but during ESWL no significant relationship was observed with the treatment side or location. Epinephrine increased significantly immediately after ESWL. hANP increased significantly immediately after ESWL, and decreased 7 days later. VPC occurred in all patients who had an hANP value above 40 pg/ml before ESWL. These results suggest that VPC is related to hemodynamic changes, and that hANP can predict VPC during ESWL.

Adult↗
PubMed1999

[Composition of vascular tree using moving-table MR angiography: development and preliminary clinical experience with a semi-automated program combining stacks of MR angiographic images].

Moving-table MR angiography, combining a contrast enhanced MRA approach with table movement, has recently become available. This technique allows imaging of long, longitudinal anatomical regions of vasculature. We have developed a semi-automated program combining stacks of MRA images obtained from different image stations, and applied it to the reconstruction of vascular trees in twenty-five patients with peripheral arterial occlusive disease. Using this program, continuous vascular trees, extending from the abdominal aorta to lower leg (up to 124 cm), were semi-automatically reconstructed within two minutes from six different projection angles. Extensive vascular lesions were recognized three-dimensionally by moving image display mode.

Arterial Occlusive Diseases↗