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Biomedical subjects

M Harada

Publications and source records attributed to M Harada.

At least 973 records · Page 54Linked to original sources
PubMed1988

Inactivation of tyrosine hydroxylase in rat striatum by 1-methyl-4-phenylpyridinium ion (MPP+).

We report that 1-methyl-4-phenylpyridinium ion (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), inactivated tyrosine hydroxylase (TH) when MPP+ was directly infused into the striatum. We examined both in vitro TH activity and TH content measured by an enzyme immunoassay in the rat striatum after MPP+ was administered by an in vivo brain microdialysis probe. MPP+ caused the inhibition of TH activity but did not influence TH content in the ipsilateral striatum. These results indicate that MPP+ may cause an acute inactivation of TH after continuous exposure at the high concentrations.

1-Methyl-4-phenylpyridinium↗
PubMed1988

Release of acetylhydrolase from platelets on aggregation with platelet-activating factor.

Acetylhydrolase, the enzyme which inactivates platelet-activating factor (PAF, 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine), was selectively released from bovine platelets by aggregation with physiological concentrations (0.1-10 nM) of PAF with no cell lysis. The release of the acetylhydrolase paralleled that of serotonin. The acetylhydrolase released was active over a broad pH range (pH 5.4-8.6) and was not affected by Ca2+ (1-4 mM) or EDTA (1-8 mM). The Km value of the enzyme was 4.6 microM. Net specific acetylhydrolase activity recovered in the 130,000 x g supernatant after stimulation with PAF could be determined in the presence of EDTA without the activity of Ca2+-dependent phospholipase A2 which was also released from the cells at the same concentration of PAF. The acetylhydrolase was inhibited competitively by specific PAF antagonists, rac-3-(N-n-octadecylcarbamoyloxy)-2-methyoxypropyl-2-thiazolioe thyl phosphate (CV-3988) and (2RS)-1-O-hexadecyl-2-O-ethyl-3-O-(7-thiazolinoheptyl)-glycerol methanesulfonate (ONO-6040). Their Ki values for the enzyme were 1.17 microM and 0.84 microM, respectively. The release of the enzyme could also be detected when the platelets were aggregated with ADP (2.3 microM) or thrombin (0.5 unit). These results suggest that the enzyme released from the aggregated platelets to the blood plasma may also have a physiological function cooperating with the plasma acetylhydrolase.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1988

The cataract Shionogi mouse, a sister strain of the non-obese diabetic mouse: similar class II but different class I gene products.

We have studied with a series of monoclonal antibodies and restriction fragment analysis the K, D, and class II region of the major histocompatibility complex of the non-obese diabetic mouse in comparison with its sister strains, the non-obese non-diabetic and cataract Shionogi mouse. (1) K region: Monoclonal antibody 31-3-4S (anti-Kd) reacted with splenocytes from non-obese diabetic mice while other anti-K (Kb, Kk, Kq) monoclonals did not react. Splenocytes from non-obese non-diabetic mice reacted with both anti-Kb and Kk monoclonals while splenocytes from cataract Shionogi mice reacted with anti-Kd and Kk monoclonals. Both sister strains, therefore, differ from the non-obese diabetic and other known mice strains by monoclonal analysis of H-2K. (2) D region: Splenocytes from both non-obese diabetic and non-obese non-diabetic mice reacted with monoclonal antibody 28-14-8S (anti-Db) while splenocytes from cataract Shionogi mice did not react with any anti-D monoclonal antibody tested. (3a) Class II region (non-obese diabetic and non-obese non-diabetic mice): Three of 11 monoclonal antibodies to class II molecules reacted with splenocytes of the non-obese diabetic mouse. The 3 reacting monoclonals have I-Ak primary specificities though additional anti-I-Ak monoclonal antibodies were negative. Among these monoclonals, 39B and 40A reacted with the non-obese diabetic mouse but not with the non-obese non-diabetic mouse, while 10-2-16 reacted with non-obese diabetic, non-obese non-diabetic and cataract Shionogi mice. Monoclonal MKD6 (anti-I-Ad) reacted with non-obese non-diabetic but not non-obese diabetic mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Homospecific activity (activity per enzyme protein) of tyrosine hydroxylase increases in parkinsonian brain.

Tyrosine hydroxylase (TH) contents in the caudate nucleus, putamen, and substantia nigra from control and parkinsonism brains were measured for the first time by a sandwich enzyme immunoassay. Both the TH protein content and TH activity (Vmax) were decreased in parallel in the parkinsonian brains as compared with those of the control brains. In contrast, TH "homospecific activity" (activity per enzyme protein) was significantly increased in the parkinsonian brains. The results indicate that the decrease of TH activity in parkinsonian brains is due to the decrease of TH protein content as a result of cell death. The increase in the "homospecific activity" of residual TH in parkinsonian brain suggests such molecular changes in TH molecules as result in a compensatory increase in TH activity.

Brain Chemistry↗
PubMed1988

Methods of removing external metal contamination from hair samples for environmental monitoring.

Human exposure to trace elements has become a major environmental issue with the growing industrialization and urbanization around the world. Hair samples are the most conveniently obtainable biopsy material and they have been identified as good indicators of the metal pollution in an environment. For their effective use, however, it is necessary to exclude the effect of external contamination of the hair surface by metals. The present investigation compares the different methods of washing hair samples prior to further treatment for elemental analysis. Deionized water, solvents (acetone, ether and carbon tetrachloride), non-ionic detergent, ionic detergent (sodium lauryl sulfate), chelating agent (EDTA-2Na), ultrasonics and combinations of these agents were used in the experiments. EDTA was found to be the most suitable of these washing agents for removing external contaminant metals. Further elucidation, however, is needed before a standard method of hair washing can be established.

Copper↗
PubMed1988

A study of the sources of external metal contamination of hair.

Sources of external metal contamination of hair were examined experimentally by exposing hair samples to soil, hot water from a water boiler for domestic use and household dust and fumes in a kitchen. Copper concentration in the hair increased markedly only when the hair was exposed to hot water from the boiler. Iron concentration in the hair increased markedly after exposure to wet soil, and increased slightly after exposure to hot water from the boiler. There was a slight decrease in zinc in the hair after exposure to wet or moist soil, and a significant increase after exposure to hot water from the boiler. When the hair was exposed to household dust and fumes, zinc showed a slight increase but copper and iron showed no change at all. The experiments with soil demonstrated the importance of water in the movement of iron from soil to hair and the role played in this process by biological factors such as soil bacteria.

Adolescent↗
PubMed1988

Stimulatory effects of bestatin on human B-cell colony formation.

Bestatin, (2S, 3R)-3-amino-2-hydroxy-4-phenylbutyryl-L-leucine, is a small molecular immunomodifier. Effects of this compound on human immune function were studied, in vitro, using the human B-cell colony formation technique. B-cell colonies were obtained from enriched B-cell populations placed in conditioned methylcellulose medium containing stimulators and irradiated T-cells as feeders. Addition to the culture of Bestatin at concentrations of 0.1 microgram/ml and 1 microgram/ml led to a significant increase (P less than 0.05) in the number of B-cell colonies and this effect was abolished when irradiated T-cells were not added to the culture. Bestatin increased soluble factor production induced by phytohemagglutinin (PHA)-stimulated T-cells. Such findings suggest that T-cells probably mediate this stimulatory effect of Bestatin on B-cell colony formation.

Adjuvants, Immunologic↗
PubMed1988

Effect of human G-CSF on clonogenic cells in acute myeloblastic leukemia.

The effects of purified human native granulocyte colony-stimulating factor (G-CSF) on the growth of clonogenic leukemic blast cells from 10 Japanese patients with acute myeloblastic leukemia (AML) were studied, using an in vitro leukemic blast colony assay. The clonogenic leukemic blast cells from six patients with AML were stimulated to form colonies in viscous medium in vitro by the addition of 100 ng/ml G-CSF. The possibility that G-CSF may be a leukemic blast growth factor warrants further attention.

Adult↗
PubMed1988

Establishment of a model to evaluate inhibition of bone resorption induced by human prostate cancer cells in nude mice.

A model system of human prostate carcinoma in nude mice for searching out a method to protect the bone from cancer cells is described, in which the transplanted human prostate cancer cells were inoculated subcutaneously over the calvaria in nude mice after the periosteum wa disrupted. The tumor induced osteolysis associated with osteoclast proliferation accompanied with reactive new bone formation. This osteolysis was evaluated by measuring the increased area of bone resorption by its reduced opacity to X-ray, and histology. Etidronate disodium, a diphosphonate derivative, at a dose of three mg./kg. and 10 mg./kg. s.c. protected the bone by decreasing the extent of osteolysis as judged by the above criteria. This inhibition was obtained with no apparent effect on the growth of the tumor. These results are discussed in light of recent clinical work, showing that this animal model is a useful tool to test the effect of new drugs against osteolysis of cancer as well as to study the biology of local interaction between bone and cancer cell.

Adenocarcinoma↗
PubMed1988

S phase fraction of human bladder tumor measured in situ with bromodeoxyuridine labeling.

A total of 18 patients with transitional cell bladder cancer was given a 0.5-hour intravenous infusion of bromodeoxyuridine at the time of endoscopic biopsy or transurethral resection to label tumor cells in the deoxyribonucleic acid synthesis phase (S phase). The tumor specimens were fixed with 70 per cent ethanol, embedded in paraffin, sectioned and stained by an indirect immunoperoxidase method with anti-bromodeoxyuridine monoclonal antibody as the first antibody. The bromodeoxyuridine labeling index, S phase fraction, was determined by counting the number of bromodeoxyuridine-labeled cells in the tissue sections. All grade 1 tumors had an S phase fraction of lower than 10 per cent. The average S phase fractions for noninvasive (11 cases) and invasive (7) tumors were 9.8 and 20.0 per cent, respectively. Two distant metastatic bladder tumors showed an average S phase fraction of 25.3 and 30.0 per cent. Thus, transitional cell bladder cancers with an S phase fraction of greater than 10 per cent appears to grow faster and be more invasive more often than those with an S phase fraction of less than 10 per cent. The higher S phase fraction may indicate greater biological malignancy. Our preliminary results suggest that measurement of the bromodeoxyuridine labeling index in bladder tumors may be a new objective and quantitative assay of biological potential of individual tumors.

Adult↗
PubMed1988

Effects of systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to mice on tyrosine hydroxylase, L-3,4-dihydroxyphenylalanine decarboxylase, dopamine beta-hydroxylase, and monoamine oxidase activities in the striatum and hypothalamus.

The effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (30 mg/kg subcutaneously per day for 8 days) to C57BL/6N mice were studied on tyrosine hydroxylase (TH), L-3,4-dihydroxyphenylalanine decarboxylase (DDC), and monoamine oxidase (MAO) activities in the striatum, and TH, DDC, dopamine-beta-hydroxylase (DBH), and MAO activities in the hypothalamus. Treatment with MPTP led to a large decrease in TH activity and a parallel decrease in DDC activity in the striatum, as compared with the saline controls. In contrast, MPTP administration did not cause a decrease of the activities of TH, DDC, and DBH in the hypothalamus. There was also no reduction in MAO activities of striatum and hypothalamus. These data indicate that MPTP administration to mice results in specific degeneration of the dopaminergic nigrostriatal pathway and that DDC in the mouse striatum may mainly be localized in the dopaminergic neurons with TH.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

Alteration of amino acid content of cerebrospinal fluid from patients with epilepsy.

The alteration of amino acids content in cerebrospinal fluids (CSF) from 31 cases of epilepsy and 10 cases of headache (as control) was studied using high performance liquid chromatography (HPLC). In patients with epilepsy, it was found that the CSF levels of GABA and aspartic acid had a tendency to decrease, but these changes were not statistically significant. In simple partial seizures, the CSF levels of glutamic acid and glycine also showed a tendency to decrease. The decrease of CSF GABA found in epileptics had a tendency to normalize following treatment with valproic acid. At the same time, administration of valproic acid induced a decrease of aspartic acid in the CSF of epileptics. These results suggest that administration of valproic acid may induce an increase in GABA and a decrease in aspartic acid in the CSF of epileptics.

Adult↗
PubMed1988

The relationship of clinical classification to ras p21 expression in human non-small cell lung cancer.

The relationship of tumor size, status of disease in the TNM classification, and stage of disease to ras oncogene expression was studied in human non-small cell lung cancer materials immunohistochemically using monoclonal antibody rp-35 against ras 21. Materials of adenocarcinoma and squamous cell carcinoma obtained from primary sites larger than 30 mm in diameter exhibited intensely positive reactions with rp-35 significantly more frequently than those with primary sites, 30 mm in diameter or smaller (p less than 0.01). Furthermore in the TNM classification, cases with T2 (with primary sites larger than 30 mm in diameter) or T3 (with direct extension to adjacent structures) showed significantly higher reaction with rp-35 than those with T1 (with primary sites 30 mm in diameter or smaller) (p less than 0.01), although N and M status did not correlate with ras p21 expression. These results suggest that ras oncogene may play a significant role in growth or tumorigenesis at the primary site in human non-small cell lung cancer.

Antibodies, Monoclonal↗