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Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

At least 649 records · Page 36Linked to original sources
PubMed1991

Reduced midbrain and pons size in children with autism.

Recent reports suggested functional abnormalities of the brain stem in autistic children. Moreover, structural brain abnormalities have also been reported, so we analyzed magnetic resonance imaging (MRI) scan in autistic children. MRI scans for 29 autistic children were compared with 15 control MRI scans. The midbrain and pons were measured. The midbrain and pons size were found to be significantly smaller in the autistic group. This suggests that the structure of the brain stem is anatomically altered in autistic children.

Autistic Disorder↗
PubMed1991

Rheumatoid factors in patients with minimal change nephrotic syndrome.

Several immunological aberrations, especially T-cell abnormalities, have been shown to be involved in the development of the minimal change nephrotic syndrome (MCNS) although the responsible factors have not been identified. We studied rheumatoid factors (RF), thought to be a consequence of polyclonal B-cell hyperactivation, in sera from patients with MCNS using a sensitive fluorescence immunoassay (FIA). Significant increases of IgG and IgM RFs and marginal increase of IgA RF were observed during the nephrotic stages. Some patients still showed high titers of IgM RF in the early remission phases. The levels of RFs were normalized during complete remission. It was suggested that polyclonal B cell activation might be involved in the development of this disorder along with T cell abnormalities.

Adult↗
PubMed1991

[Relation of hepatic protein synthesis and hepatic functional mass in obstructive jaundiced rats].

In obstructive jaundiced rat, the change of hepatic functional mass assessed by [14C]-aminopyrine breath test (ABT) and galactose tolerance test (GaTT) and hepatic protein synthesis measured by [14C]-leucine incorporation into hepatic protein fraction were investigated. Bile duct ligation (BDL) for 5 and 14 days was followed by choledocho-duodenal fistula as the relief of obstruction. Hepatic functional mass measured by ABT and GaTT revealed a remarkable decrease at 5 and 14 days after BDL without differences in grades. These depressed values returned to the preoperative ones in 10 to 20 days after the relief of obstruction. On the contrary, hepatic protein synthesis was reciprocally enhanced after BDL. After the relief of obstruction the enhancement of hepatic protein synthesis was prolonged and then returned to the normal level in 20 days. These data suggested that in obstructive jaundice hepatic protein synthesis was stimulated by several stress and continued to be enhanced even after the relief of obstruction. These enhancement of hepatic protein synthesis would induce to decrease hepatic functional mass.

Aminopyrine↗
PubMed1991

[Hepatic functional evaluation using the galactose tolerance test in patients with obstructive jaundice].

Hepatic functional mass was evaluated in patients with obstructive jaundice using the galactose tolerance test (GaTT), which reflected cytosolic function of hepatocyte. The T-1/2 values as an index on the GaTT were significantly prolonged in patients with obstructive jaundice in comparison with control subjects whether before or after percutaneous transhepatic biliary drainage (PTBD). But in each cases, some showed nearly normal GaTT-T/2 value and others showed severely prolonged value. Patients with obstructive jaundice could be divided into two groups according to the GaTT-T/2 value before PTBD. The decreasing rate of serum bilirubin level "b" after PTBD was significantly fair in the group A patients (good GaTT-T/2 value before PTBD) than the group B (poor GaTT-T/2 value before PTBD) (P less than 0.05). It was that GaTT-T/2 before PTBD which represented hepatic cytosolic functional mass could predict the effect of PTBD in patients with obstructive jaundice.

Aged↗
PubMed1990

Determination of methamphetamine, amphetamine and piperidine in human urine by high-performance liquid chromatography with chemiluminescence detection.

A high-performance liquid chromatographic method for the determination of trace levels of methamphetamine, amphetamine and piperidine in human urine is reported. The three compounds, extracted into diethyl ether from alkaline urine, were derivatized with dansyl chloride, then separated on a reversed-phase column and detected by chemiluminescence after reaction with bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide. The corresponding peaks obtained from human urine were identified as the dansyl derivatives by mass spectrometry. Methamphetamine levels as low as 2 x 10(-10) M in urine were determined. The sensitivity of the method is higher than that of Simon's reagent test and gas chromatography.

Amphetamine↗
PubMed1990

The mitotic apparatus-associated 51-kDa protein from sea urchin eggs is a GTP-binding protein and is immunologically related to yeast polypeptide elongation factor 1 alpha.

We investigated the biochemical characteristics of the 51-kDa protein that is a major mitotic apparatus-associated basic protein of sea urchin eggs (Toriyama, M., Ohta, K., Endo, S., and Sakai, H. (1988) Cell Motil. Cytoskeleton 9, 117-128). The amino acid composition of the 51-kDa protein was apparently different from those of tubulin, actin, histones, and myelin basic protein; yet it was similar to those of polypeptide elongation factors 1 alpha (EF-1 alpha). In addition, antibody to EF-1 alpha from yeast cross-reacted with the 51-kDa protein. [3H] GTP binding activity was detected in the phosphocellulose-purified fraction (PC fraction) which predominantly contained the 51-kDa protein and was shown to be specific to GTP, GDP, guanylyl imidodiphosphate, and ITP. Photo-affinity labeling using [alpha-32P]8-azidoguanosine triphosphate (8-azido-GTP) demonstrated that a 51-kDa polypeptide in the PC fraction specifically bound 8-azido-GTP. This GTP-binding polypeptide was bound to a GTP affinity column, could be eluted by the addition of GTP, and was immunoreactive with anti-51-kDa protein antibodies. When the PC fraction was applied to a gel filtration chromatography column, GTP binding activity was completely coeluted with the 51-kDa protein. Furthermore, the PC fraction and the gel filtration-purified fraction had EF-1 alpha activity: [14C]Phe-tRNA transferring activity to ribosomes in the presence of poly(U) and ribosome-dependent GTPase activity. The results indicate that the mitotic apparatus-associated 51-kDa protein is a GTP-binding protein and suggest that it is structurally and functionally related to yeast EF-1 alpha.

Affinity Labels↗
PubMed1990

Drug resistance to cis-diamminedichloroplatinum (II) in Chinese hamster ovary cell lines transfected with glutathione S-transferase pi gene.

Establishment of Chinese hamster ovary (CHO) cell lines expressing human glutathione S-transferase-pi (GST-pi) was performed after cotransfection of pSV2-neo and human GST-pi cDNA-carrying plasmid p beta actGPi-2. About 30 G418-resistant clones were tested for their expression of GST-pi by Northern blot analysis. Two clones, beta 2-3 and beta 2-5, expressed a significant amount of GST-pi mRNA; and one clone, beta 1-1, that did not was also used for further study. Western blot analysis with anti-GST-pi antibody showed significant increases of GST-pi in beta 2-3 and beta 2-5, but not in beta 1-1. Northern blot analysis with the human GST-pi cDNA probe showed that the increase in the expression of GST-pi-mRNA in beta 2-3 and beta 2-5 was respectively 2- and 4-fold higher than that in beta 1-1. Southern blotting analysis showed that beta 1-1, beta 2-3 and beta 2-5 contained about one copy of the human GST-pi cDNA sequence. beta 2-3 and beta 2-5 were resistant to 1.4- and 3.0-fold higher doses of CDDP than CHO, respectively, but beta 1-1 was not. Increased expression of GST-pi might be associated with CDDP-resistance in CHO cells.

Animals↗
PubMed1990

Studies on the effects of imidazole on the peroxyoxalate chemiluminescence detection system for high performance liquid chromatography.

The catalytic effect of bases (imidazole, pyridine, Tris and triethylamine) on the peroxyoxalate chemiluminescence (PO-CL) reaction for high performance liquid chromatography (HPLC) was investigated. Imidazole increased PO-CL intensity extraordinarily, whereas the other bases (pyridine, Tris and triethylamine) did not. The peak heights of dipyridamole (coronary vasodilator) obtained using the eluents containing buffers were largest at pH 7.0, a few times less at pH 6.0 and pH 5.0, 100 times less at pH 4.0 and a few hundred times less at pH 3.0. The eluents containing buffers at pH 3, 4, 5, 6 or 7 each with imidazole increased the peak heights by a few to ten times as compared with those without imidazole, and those peak heights were within one order of magnitude. On the other hand, the eluent containing buffer at pH 2 did not affect the peak heights with or without imidazole. Bis(4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl) oxalate (TDPO) alone and bis(2,4-dinitrophenyl)oxalate (DNPO) plus TDPO were recommended to be used against eluents containing buffers of pH 5-7 and pH 3-4, respectively. Dipyridamole and benzydamine hydrochloride (anti-inflammatory drug) were separated on the ODS column and detected by the present system. The detection limits of dipyridamole and benzydamine hydrochloride were 40 amol and 270 fmol, respectively.

Chromatography, High Pressure Liquid↗
PubMed1990

Determination of nitrated pyrenes and their derivatives by high performance liquid chromatography with chemiluminescence detection after online electrochemical reduction.

A sensitive and selective high performance liquid chromatographic method for the simultaneous determination of nitrated polycyclic aromatic hydrocarbons and their reduced compounds has been developed. As the model compounds for the proposed method, pyrene, aminopyrene, nitrosopyrene, and several nitrated pyrenes were used. After separation on a reversed phase column, both nitropyrenes and nitrosopyrene which were not fluorescent, were electrochemically reduced to strongly fluorescent aminopyrenes, and detected chemilumigenically by using bis(2,4,6-trichlorophenyl)oxalate and hydrogen peroxide as post column reagents. Their detection limits were all at the fmol levels, which were one or two orders lower than those by fluorescence detection. By the proposed method, nitropyrene, 1,3-, and 1,8-dinitropyrenes were detected in sooty emissions of cars after simple purifications.

Chromatography, High Pressure Liquid↗
PubMed1990

Enhancing effect of S-(1,2-dicarboxyethyl)glutathione on epidermal growth factor-stimulated DNA synthesis in primary cultures of adult rat hepatocytes.

A tripeptide S-(1,2-dicarboxyethyl)glutathione (DCE-GS) has been reported to be present in the lens, liver, and heart. Effects of DCE-GS and its derivatives and analogues on hepatocyte deoxyribonucleic acid (DNA) synthesis were examined using primary cultures of adult-rat hepatocytes. DCE-GS alone had no effect on DNA synthesis of hepatocytes. However, when DCE-GS was added with epidermal growth factor (EGF), the tripeptide effectively enhanced EGF-stimulated DNA synthesis of hepatocytes under the culture conditions of low cell density, but not high cell density. On the other hand, some esters and amides of DCE-GS and DCE-GS analogues showed a suppressive effect on DNA synthesis of hepatocytes in the absence of EGF. The derivatives and analogues together with EGF had no effect or rather a suppressive effect on stimulation of hepatocyte DNA synthesis by EGF. Therefore, the two carboxy groups in the substituent probably play an important role in the stimulative activity of DCE-GS. In addition, it seems likely that one of in vivo physiological roles of DCE-GS is related to liver regeneration.

Animals↗
PubMed1990

Influence of liver tumor promoters and structurally related chemicals on survival of normal adult rat hepatocytes in primary culture.

The influence of four liver tumor promoters and two structurally related chemicals (non-promoters) on survival of normal adult rat hepatocytes was examined in primary culture. Of the four promoters, butylated hydroxytoluene (BHT), dichlorodiphenyltrichloroethane (DDT), barbital sodium and phenobarbital sodium, only phenobarbital efficiently prolonged the hepatocyte survival and maintained the morphological features of the cells. Both BHT and DDT were toxic to hepatocytes within the dose ranges tested. Barbital was also ineffective for maintenance of primary cultured hepatocytes but not toxic to the cells. Of the two non-promoters, barbituric acid and amobarbital, barbituric acid also showed no maintenance effect on hepatocytes. However, amobarbital resembled phenobarbital in its effect on the maintenance of hepatocytes in primary culture. DNA synthesis of primary cultured hepatocytes was severely suppressed by phenobarbital in a dose-dependent manner. The results clearly show that the ability to support long-term survival of primary cultured hepatocytes is a common property of some barbiturates but not of liver tumor promoters, and that the maintenance of hepatocytes by phenobarbital is not due to a counterbalance of stimulated proliferation and death of the cells.

Animals↗
PubMed1990

Adjunctive treatment for recurrent childhood ependymoma of the IV ventricle: chemotherapy with CDDP and MCNU.

The prognosis of recurrent IV-ventricle ependymoma in children is poor. Three cases of recurrent ependymoma were treated with combination chemotherapy using cis-diamine dichloro platinum (II) (CDDP) and methyl-6-(3-(2-chloroethyl)-3-nitrosoureido)-6-deoxy-alpha-D-glucopyrano side (MCNU). The patients were 2-, 3-, and 6-year-old boys. The interval between the first operation with irradiation and recurrence was 1 year and 5 months to 2 years. Two cases showed a recurrence at the original site; in the other case, a right sylvian tumor deposit was found via computed tomography. The therapeutic regiment for recurrent ependymomas was as follows: (1) the tumor was debulked if possible; (2) additional local irradiation of 30 Gy was administered; (3) combined treatment of 100 mg/m2 CDDP and 80 mg/m2 MCNU over 24 h was given 5 times with an interval of 6 weeks between treatments. The patients tolerated the therapy well with only mild side effects. Remission lasted 1 year in two patients and has lasted for 8 months in one.

Antineoplastic Agents↗
PubMed1990

A comparative study of measurement of arterial blood pressure using HEM-802F and arterial cannulation.

Finger arterial blood pressures determined by a newly developed sphygmomanometer, HEM-802F, were compared with arterial pressure obtained from direct measurement of the radial artery. An excellent correlation was found between the two methods (systolic: r = 0.93, diastolic: r = 0.91), although there was a large variability among individual subjects. The range of differences between them are from +32 to -13 mmHg for systolic and +15 to -25 mmHg for diastolic blood pressure measurement. HEM-802F underestimated systolic pressure (-4.0 mmHg) and overestimated diastolic pressure (+6.7 mmHg), compared with intra-arterial readings. The HEM-802F was useful for the non-invasive arterial pressure monitoring during general anesthesia.

Journal Article↗
PubMed1990

Changes in brain monoamines and their metabolites during and after hemorrhagic shock in the rat.

The alteration of monoamines and their metabolites in the brain during and after hemorrhagic shock in the conscious state was measured in rats. Blood pressure was maintained at 40-70 mmHg (5.3-9.3 kPa) for 60 min by withdrawing 8 ml of blood intermittently. The content of monoamines, as well as their metabolites, increased in various brain regions during hemorrhage, compared with the content in the control rats. Sixty min after the end of the bleeding period, almost no significant change in the contents of brain monoamines nor of their metabolites was observed. These results may indicate not only an increased release of monoamines from nerve terminals, but also an increased synthesis of them during hemorrhagic shock. Soon after the bleeding was stopped, the increased monoamine turnover rate returned to almost normal levels.

Journal Article↗
PubMed1990

Hemorrhage-induced regional brain thyrotropin-releasing hormone release in conscious rats measured by microdialysis.

The septum, nucleus accumbens and preoptic area in the brains of conscious, freely moving rats were perfused using microdialysis probes. The TRH concentration significantly increased in the septum after withdrawal of 30% of the total blood volume but remained at constant levels in the other brain areas. Also, high potassium dose-dependently stimulated TRH release in vivo. These results suggest that blood loss stimulates septal TRH release, probably by membrane depolarization of TRH-containing nerve terminals.

Animals↗
PubMed1990

Cranial MR imaging in patients with von Recklinghausen's disease (neurofibromatosis type I).

MR imaging was performed for 24 patients with von Recklinghausen's disease. Twenty of the 24 patients showed abnormal findings in MR imaging. In many cases, the lesions were multifocal. In 14 patients small focal areas of increased signal on T2-weighted images were thought to represent heterotopias or hamartomas. Eight patients had optic tract gliomas. Three patients had parenchymal gliomas. In one patient, white matter showed high intensity on T2-weighted images representing delayed myelination. The rate of abnormal findings was higher for MR imaging than CT. MR imaging was found to be an excellent imaging method for known diseases and for detecting lesions in asymptomatic patients.

Adolescent↗