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Biomedical subjects

H Ihara

Publications and source records attributed to H Ihara.

At least 37 records · Page 2Linked to original sources
PubMed2001

The differential effect of angiotensin II and angiotensin 1-7 on norepinephrine, epinephrine, and dopamine concentrations in rat hypothalamus: the involvement of angiotensin receptors.

Angiotensin 1-7 has been recently claimed the active member of the angiotensins' family. In the present study we compared the effect of angiotensin II and angiotensin 1-7 on the concentration of dopamine, serotonin, epinephrine, and norepinephrine and some of their metabolites in the rat hypothalamus, where the levels of angiotensins are particularly high. Intracerebroventricular injection of angiotensin II, but not angiotensin 1-7, time-dependently elevated the levels of both epinephrine (p < 0.05) and norepinephrine (p < 0.05) in the hypothalamus and both effects could be prevented by intracerebroventricular injection of either AT(1) (candesartan), AT(2) (PD123319) or AT(1-7) (A-779) receptor antagonist. Neither angiotensin II nor angiotensin 1-7 produced any changes in the level of dopamine, dihydroxyphenylacetic acid, homovanilic acid, serotonin, 5-hydroxyindoleacetic acid, or tryptophan at any time point in comparison with the control groups. However, AT(1) but not AT(2) receptor blockade, unmasked the stimulatory effect of angiotensin 1-7 on dopamine concentration in the hypothalamus. Thus, angiotensin II and its active metabolite angiotensin 1-7 regulate selectively, albeit differentially, adrenergic, noradrenergic and dopaminergic systems in the hypothalamus, the effects that involve AT(1), AT(2) and AT(1-7) angiotensin receptors.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2001

Successful treatment of low-flow priapism associated with phenothiazine therapy.

We present a case of low-flow priapism that was successfully treated. A 21-year-old man with a history of schizophrenia was admitted with a painful complete erection. He had taken propericiazine, phenothiazine derivatives, before hospitalization and was treated with a glandular-cavernosal shunt (El-Ghorab's procedure). Currently, he is able to have erections without any changes in his quality of life.

Adult↗
PubMed2001

Comparison of the sensitivity of NAT using pooled donor samples for HBV and that of a serologic HBsAg assay.

BACKGROUND: Studies were conducted using samples from early and late-stage HBV-infected persons to determine the pool size at which PCR had better sensitivity than a sensitive HBsAg chemoluminescence immunoassay (CLIA-HBsAg). STUDY DESIGN AND METHODS: HBV seroconversion panels were tested for HBsAg by CLIA and for HBV DNA by nested PCR (95% hit rate: 100 copies/mL); PCR was carried out at various dilutions. HBV serologically positive samples that were detected from the simultaneous screening of 540,161 routine whole-blood donations using CLIA-HBsAg and agglutination assays were also characterized for additional markers of HBV infection. RESULTS: In 9 of 10 HBV seroconversion panels, PCR had better sensitivity than CLIA-HBsAg at dilutions of 1-in-25 or lower. Of 65 CLIA-only confirmed-positive donor samples (agglutination assay-negative), 8 represented early infection, 2 of which were PCR positive at a 1-in-50 dilution but negative at a 1-in-100 dilution. Only 2 of 47 samples from probable late-stage HBV infection that were positive on CLIA only were PCR positive with 0.1-mL sample volume and the S-region primer; the remaining 45 samples required a 1.0-mL sample input and C-region primer for increased PCR positivity. The remaining 10 CLIA-only confirmed-positive donor samples were from HBV vaccine recipients. None of the 12 CLIA- and HBsAg-negative donor samples that were strongly anti-HBc reactive could be detected by PCR at any dilution; all 12 were PCR positive when undiluted, but 4 required a 1.0-mL input volume for PCR positivity. CONCLUSION: For the detection of samples representing early-stage HBV infection, PCR at dilutions of 1-in-25 or lower (equivalent to a pool of < or =25 members) had greater sensitivity than CLIA-HBsAg. In contrast, samples from late-stage HBV infection were detected by PCR only with undiluted samples (0.1-mL or 1.0-mL input volumes), regardless of CLIA-HBsAg reactivity. Therefore, although NAT using minipools of 25 donations or less may be effective for the detection of early-stage HBV infection, it may not be effective for the detection of persistent HBV infection.

Blood↗
PubMed2001

Tissue-type plasminogen activator is involved in the process of neuronal death induced by oxygen-glucose deprivation in culture.

Effect of tissue-type plasminogen activator (tPA) on oxygen-glucose deprivation (OGD) was studied in cultured cortical neurons prepared from tPA gene knockout (tPA-KO) and wild-type (Wt) mice. Three hours of OGD induced 45% and 23% of neuronal death in Wt and tPA-KO mice, respectively. Neuronal death in tPA-KO mice was increased to 42% by additional tPA. Six hours of OGD induced 80% and 40% of neuronal death in Wt and tPA-KO mice, respectively, whereas the addition of tPA increased to 62% in tPA-KO mice. These results suggest that tPA is directly involved in the process of neuronal death induced by ischemia-mimic stress without involving vascular or circulatory components.

Animals↗
PubMed2001

[A case of pheochromocytoma with von Recklinghausen's and review of 67 Japanese cases].

A 19-year-old woman with von Recklinghausen's disease was referred to our hospital because of right adrenal pheochromocytoma. The tumor was detected incidentally with the abdominal ultrasonography when she complained epigastralgia to the home doctor who treated her hypertension. Plasma and urinary catecholamines level were elevated. The tumor was removed by laparoscopy assisted adrenalectomy without pneumoperitoneum. The resected specimen was 35 x 60 x 75 mm in size and weighed 70 g. Pathological diagnosis was adrenomedullary pheochromocytoma. Postoperative course was uneventful. She has been well with no signs of recurrence after 7.5 years. We reviewed 67 Japanese patients previously reported as von Recklinghusen's disease with pheochromocytoma. Of the 60 patients whose details were described, 16.7% had metastases and pathological malignancy from pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed2000

Retention versatility of silica-supported comb-shaped crystalline and non-crystalline phases in high-performance liquid chromatography.

Silica-supported comb-shaped polymer (Sil-ODA18) provided a specific selectivity towards aromatic and non-aromatic solutes. Selectivity of Sil-ODA18 and ODS (polymeric and monomeric) columns towards polycyclic aromatic hydrocarbons and geometric isomers have been discussed in respect of molecular shapes and sizes. The retention versatility of this phase arises from the orientation change on transition from the ordered crystalline to the less ordered non-crystalline state. Selectivity in the crystalline and non-crystalline regions of Sil-ODA18 is similar to that of polymeric and monomeric ODS phases, respectively. Sil-ODA18 column also exhibited the characteristic temperature dependency of liquid-crystalline phases, i.e., an increase in retention with increasing temperature on transition from crystalline to isotropic state.

Chromatography, High Pressure Liquid↗
PubMed2000

Differential effects of nicotine against stress-induced changes in dopaminergic system in rat striatum and hippocampus.

A number of studies have shown an increase in nicotine self-administration among smokers when exposed to stress. Since it is well known that nicotine or stress alter the dopaminergic system, we examined the effect of chronic nicotine administration on the dopamine level and its metabolism in the striatum and the hippocampus during stressful conditions in rats. Nicotine (0.4 mg/kg, i.p. for 14 days) increased the dopamine level in the striatum (P<0. 05) and decreased it in the hippocampus (P<0.05) in comparison with the effect of saline. Three hours of water-immersion restraint stress sharply elevated the dopamine level (P<0.05) and reduced the 3-methoxytyramine level (P ranged from 0.05 to 0.001 depending on the area and time point) in both brain regions studied, while dihydroxyphenylacetic acid and homovanilic acid levels were not altered. Nicotine pretreatment attenuated some of these changes in a region- and time-dependent manner. However, stress induced a decrease in dopamine turnover in the hippocampus (P<0.05) but not in the striatum, and nicotine failed to prevent this effect. Stress-induced alterations gradually returned toward normal during the 48-h observation period, and in some cases this was facilitated by nicotine. Thus, we demonstrated differential, region- and time-dependent protective effects of chronic nicotine administration against stress-induced changes in dopamine levels and release in brain regions critically affected by stress.

Animals↗
PubMed2000

An automated assay for measuring serum ascorbic acid with use of 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy, free radical and o-phenylenediamine.

We developed a novel, cost-effective, and automated assay for ascorbic acid (AsA) in serum using a COBAS MIRA S analyzer (Roche Diagnostic System). Our method has a wide dynamic range and covers AsA concentrations from well below the lower reference interval to well above it. AsA is oxidized by 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy, free radical (TEMPO) to dehydroascorbic acid (DAsA). The latter condenses with o-phenylenediamine (OPDA) to form a quinoxaline derivative that absorbs light at 340 nm. The change in absorbance at 340 nm is proportional to the concentration of AsA in the specimen. The automated system permitted the assay of 65 specimens per hour at a cost of approximately US$ 0.01 per specimen for reagents. The assay can be applied directly to serum specimens (direct method) and also to sera with a prior deproteinization step with metaphosphoric acid. The detection limit for the direct serum assays is 0.8 vs. 0.4 mg/l with the deproteinization method. The recovery of AsA from a supplemented serum pool was of >95% for both procedures. We used four distinct methods on 66 patients sera. The direct method for AsA correlated well with an HPLC method (r=0.964, P<0.001); the direct method also correlated well with a method that uses AsA oxidase (r=0.975, P<0. 001). The deproteinization method correlated well with HPLC (r=0.981, P<0.001), and with the AsA oxidase procedure (r=0.994, P<0.001). Ten within-day determinations on a serum pool gave a C.V. <4.3% for both the direct and deproteinization procedures. The between-day assays of the same serum pool over 10 days gave a C.V. of <6.7% by both methods.

Artifacts↗
PubMed2000

Correlation dimension of the human sleep electroencephalogram.

Sleep electroencephalogram (EEG) was analyzed by nonlinear analysis. Polysomnography of a healthy male subject was analyzed and the correlation dimension was calculated. The mean correlation dimensions decreased from stage 'awake' to stages 1, 2 and 3, and increased during rapid eye movement (REM) sleep. These results were also seen at every sleep cycle. During each sleep cycle the correlation dimensions decreased for slow wave sleep, then increased for REM sleep. The mean correlation dimension of the sleep EEG in the second half of the night was significantly higher than those in the first half of the night. A significant change was seen both during REM sleep as well as in sleep stage 2. Nonlinear analysis may be a useful method in the analysis of the entire sleep electroencephalogram.

Adult↗
PubMed2000

Analysis of the human sleep electroencephalogram by the correlation dimension.

Sleep electroencephalograms (EEG) of healthy male subjects were analyzed by the correlation dimension. The mean correlation dimensions significantly decreased from stage 'awake' to stages 1, 2 and 3 and increased during rapid eye movement sleep. The mean correlation dimensions of the sleep EEG in the second half of the night were significantly higher than those in the first half of the night. These significant changes were also seen during sleep stage 2.

Adult↗
PubMed2000

Coagulation-associated enhancement of fibrinolytic activity via a neutralization of PAI-1 activity.

Total fibrinolytic activity in the vasculature is finely tuned by the balance between tissue plasminogen activator and plasminogen activator inhibitor type 1 (PAI-1). Although PAI-1 targets plasminogen activators, it also reacts with other serine proteases such as thrombin and factor Xa. The latter was shown to interact with PAI-1 only when a physiological concentration of calcium ions (Ca++) is present. Through such interaction, thrombin and Ca++-bound factor Xa shortened fibrin clot lysis times in a purified system by neutralizing PAI-1 activity. Both unfractionated heparin and vitronectin were shown to enhance the clot lysis further. Together with the cleavage and inactivation of PAI-1 by human neutrophil elastase, which was reported previously from our laboratory, such neutralization of PAI-1 activity by these serine proteases was shown to be strongly involved in the coagulation-associated enhancement of fibrinolytic activity.

Anticoagulants↗
PubMed2000

Genomic structure and promoter analysis of the human alpha1, 6-fucosyltransferase gene (FUT8).

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1,6-fucosyltransferase (alpha1,6FucT) catalyzes the transfer of a fucosyl moiety from GDP-fucose to the asparagine-linked GlcNAc residue of complex N-glycans via alpha1,6-linkage. We have cloned the genomic DNA which encodes the human alpha1,6FucT gene ( FUT8 ) and analyzed its structure. It was found that the gene consists of at least nine exons spanning more than a 50 kbp genomic region, and the coding sequence is divided into eight exons. The translation initiation codon was located at exon 2, and thus exon 1 encodes only 5'-untranslated sequences. Transcription initiation site of FUT8 was determined by 5'-rapid amplification of the cDNA end and a primer-extension analysis using the total RNA isolated from SK-OV-3 cells, which have a high level of alpha1,6FucT activity. We then characterized the FUT8 promoter region by a reporter gene assay. The luciferase reporter assay indicated that the 5'-flanking region of exon 1, which covered about 1 kbp, conferred the promoter activity in SK-OV-3 cells. This region contains potential binding sites for some transcription factors, such as bHLH, cMyb, GATA-1, as well as a TATA-box, but not a CCAAT motif. 5'-Untranslated sequences found in ESTs and the cDNA for the FUT8 suggest the presence of an additional exon(s) at the upstream of the first exon identified in this study, and therefore, the transcription of the gene would be regulated by multiple promoters.

Base Sequence↗
PubMed2000

Kinetic basis for the donor nucleotide-sugar specificity of beta1, 4-N-acetylglucosaminyltransferase III.

The kinetic basis of the donor substrate specificity of beta1, 4-N-acetylglucosaminyltransferase III (GnT-III) was investigated using a purified recombinant enzyme. The enzyme also transfers GalNAc and Glc moieties from their respective UDP-sugars to an acceptor at rates of 0.1-0.2% of that for GlcNAc, but Gal is not transferred at a detectable rate. Kinetic analyses revealed that these inefficient transfers, which are associated with the specificity of the enzyme, are due to the much lower V(max) values, whereas the K(m) values for UDP-GalNAc and UDP-Glc differ only slightly from that for UDP-GlcNAc. It was also found that various other nucleotide-Glc derivatives bind to the enzyme with comparable affinities to those of UDP-GlcNAc and UDP-Glc, although the derivatives do not serve as glycosyl donors. Thus, GnT-III does not appear to distinguish UDP-GlcNAc from other structurally similar nucleotide-sugars by specific binding in the ground state. These findings suggest that the specificity of GnT-III toward the nucleotide-sugar is determined during the catalytic process. This type of specificity may be efficient in preventing a possible mistransfer when other nucleotide-sugars are present in excess over the true donor.

Acetylgalactosamine↗
PubMed2000

Group and case study of the dysexecutive syndrome in alcoholism without amnesia.

OBJECTIVES: To test the dysexecutive syndrome (DES) hypothesis of chronic alcoholism by the neuropsychological group and case study approaches. METHODS: A comprehensive neuropsychological assessment, including the "behavioural assessment of dysexecutive syndrome", a battery of tests recently designed to be "ecologically valid", was administered to 17 patients with chronic alcoholism without amnesia to examine executive functions, intelligence, and memory. In terms of each neuropsychological measure, reciprocal analyses of group means and individual case profiles were conducted: for the first contrasting the alcoholic patients with 17 age matched healthy subjects; and for the second making intersubject and intrasubject comparison of the patients, according to percentile basis impairment indices obtained from the control subjects. RESULTS: Despite relatively unimpaired memory and intelligence, the patients as a whole had the impairment of a wide range of executive domains, extending to "everyday" problem solving as well as more elementary aspects of executive functions, such as visuospatial performance, mental set shifting, and the inhibition of habitual behaviour. The profile analysis divided individual patients into four groups: the representative DES characterised by a clear dissociation between impaired executive functions and preserved intelligence and memory; the group of a modified dysexecutive pattern in which memory as well as executive functions were impaired with intelligence preserved; the group of general cognitive deterioration; and the group of unimpaired cognitive functioning. About two thirds of the patients were categorised into either the first or the second type of DES. CONCLUSION: DES characterised by the even more pronounced impairment of executive functions than of intelligence and memory afflicts a considerable proportion of patients with chronic alcoholism. Due to its subtlety, this would be potentially left out, unless appropriate behavioural measures were administered. This condition may prevent patients with alcoholism from achieving full recovery and benefiting from rehabilitation.

Activities of Daily Living↗
PubMed2000

Removal of parvovirus B19 from hemoglobin solution by nanofiltration.

Parvovirus B19 (B19), which may contaminate red cell components for blood transfusion, is known to be resistant to several viral inactivation methods. To increase the safety of hemoglobin solutions as a source of red cell substitutes, we investigated the removal of parvovirus B19 from hemoglobin solution using nanofiltration. The hemoglobin solution spiked with parvovirus B19 was tangentially filtered using the BMM-35 filter (mean pore size of 35 nm) followed by BMM-15. The parvovirus B19 of 10(8.5) PT50 (median PCR titer)/10 microL was not changed after the BMM-35 filtration. However, the BMM-15 filtration decreased the parvovirus B19 from 10(8.3-8.7) PT50 to 10(1.3-2.2) PT50, indicating more than 6 log10 reduction. When the initial parvovirus B19 of 10(6.0) PT50 was subjected to the BMM-15 filtration, the residual virus was 10(-0.3-0.5) PT50 orundetected in some fraction of the filtrate. Hemoglobin recovery was 70.4 +/- 3.4%. The ratio of methemoglobin was not changed during the filtration. These findings indicate that the BMM-15 filtration is a promising approach to prepare a safer hemoglobin solution for red cell substitutes.

Blood Substitutes↗
PubMed2000

Clinical and analytical evaluation of the simultaneous HPLC assay of retinol and alpha-tocopherol.

We describe a method for the simultaneous assay of retinol and alpha-tocopherol using normal-phase, high-performance liquid chromatography (HPLC). Our normal-phase HPLC method gave better resolution (Rs) of retinol (Rs= 1.58) and alpha-tocopherol (Rs = 1.40) when compared with the Rs values for a-tocopherol and retinol from literature. Also, the alpha-tocopherol concentrations obtained by our method agreed well with another normal-phase HPLC method that used fluorometric detection (r = 0.951, p<0.001. Sy.x=0.58 mg/L). The concentrations of retinol in our method agreed well with those determined by a reversed-phase HPLC procedure, although the correlation (r=0.646, p<.001, Sy.x=62 microg/L) was not as good as the method proposed. Our procedure gave acceptable precision: the within-run CV was 7.7% for alpha-tocopherol and 5.9% for retinol. The between-day CV was 9.0% for alpha-tocopherol and 6.8% for retinol. The mean recoveries were 97% for alpha-tocopherol and 107% for retinol. Our assays were linear for alpha-tocopherol concentrations from 0.1 to 30 mg/L and for retinol concentrations from 20 to 2,000 microg/L. In children ages 7 to 12 y, and in adolescents ages 14 to 16 y, the alpha-tocopherol and retinol concentrations in the blood were significantly lower than the concentrations in normal adults. Individuals over 70 y old also showed alpha-tocopherol and retinol values that were lower than those of normal adults between ages 30 and 40 y. In female university students, the inter-individual variation of alpha-tocopherol was reduced by dividing the alpha-tocopherol results by their total cholesterol or total lipid concentrations; however, this was not obtained for retinol. In cancer patients undergoing surgery, the ratio of retinol to retinol-binding protein (RBP) remained fairly constant, although the concentrations of both retinol and RBP decreased to about one-half the preoperative values after surgery. We conclude that our normal-phase HPLC method is a stable and reproducible method for alpha-tocopherol and retinol, and is an easy-to-use analytical tool.

Adolescent↗
PubMed2000

A simple and rapid method for the routine assay of total ascorbic acid in serum and plasma using ascorbate oxidase and o-phenylenediamine.

A simple and rapid analysis of total ascorbic acid (AsA) in serum and plasma and its automated analysis are described. AsA is oxidized by ascorbate oxidase (AsA oxidase) to dehydroascorbic acid that then reacts with o-phenylenediamine (OPDA) to form a quinoxaline derivative that absorbs at 340 nm. The change in absorbance is directly proportional to the total AsA concentration. The assay was validated with a linear concentration range of 0.8-80 mg/L, and the within-day and between-day assays precision did not exceed 8.6% and 12.5%, respectively. On 47 sera, the manual enzymatic procedure gave 0.2 mg/L on average lower values than those of an automated enzymatic procedure with a correlation coefficient of 0.847. On another 66 sera, results by automated enzymatic method correlated well with the HPLC method and the regression equation is Y (enzymatic, automated)=0.97 X (HPLC)+0.1, r=0.980, Sy.x=0.6 mg/L. An experienced analyst can perform about 24 manual assays per hour whereas the automated procedure gave a rate of 100 assays per hour.

Ascorbate Oxidase↗