Search PubMed⌕ Search

Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 253 records · Page 14Linked to original sources
PubMed1996

[Higher expression levels of alternatively spliced pX mRNA in human T lymphotropic virus type I (HTLV-I) asymptomatic carriers positive for antibodies to p40tax protein].

We cloned and sequenced complementary DNA (cDNA) of human T lymphotropic virus type I (HTLV-I) pX gene mRNA expressed in peripheral blood lymphocytes of asymptomatic carriers and searched for a possible correlation between HTLV-I pX mRNA expression levels to viral load and anti-p40tax status. Nine cDNA clones had four alternatively spliced forms of mRNA, three forms were identical to the reported cDNA sequences. One cDNA clone contained a novel splicing acceptor site, thereby indicating an unidentified form of pX mRNA, termed as pX delta 17 delta 37. These results, together with previous observations, suggest that HTLV-I has complex pattern of splicing. The expression levels of the five pX mRNAs, pX, pX delta 17, p21rex, orf II, and pX delta 17 delta 37, were examined in twenty-one asymptomatic carriers. Alternatively spliced pX mRNA species were detected in all the carriers. Semiquantitation of pX mRNAs revealed that pX and pX delta 17 were the dominant mRNA species among alternatively spliced pX mRNA. All pX mRNAs but the orf II message correlated with amounts of proviral DNA significantly (p < 0.05). The levels of proviral DNA and mRNAs were significantly higher in anti-p40tax positive carriers than in negative ones. These observations suggest that the alternatively spliced pX mRNAs are expressed ubiquitously in the peripheral blood lymphocytes of HTLV-I asymptomatic carriers with complex pattern of splicing and that the presence of anti-p40tax may be a marker for a higher viral load and viral replication levels in HTLV-I asymptomatic carriers. Our observations may explain previous finding that the carriers rate is higher in the offspring of anti-p40tax positive mothers than those of anti-p40tax negative mothers.

Aged↗
PubMed1996

Acetohexamide reductase activities in liver microsomes and cytosol of cisplatin-treated male rats: cisplatin indirectly modulates the microsomal enzyme activity.

Treatment with cisplatin, at a dose of 7.2 mg/kg body weight, caused a significant decrease of acetohexamide reductase activity in liver microsomes of male rats at 4 and 7 days after its treatment; this dose of cisplatin has been reported to decrease testosterone levels in serum of male rats. However, the treatment with cisplatin could not decrease acetohexamide reductase activity in liver cytosol of male rats at the days tested. Although acetohexamide reductase activity in liver microsomes of male rats, as described above, was decreased by the treatment with cisplatin, the decreased microsomal enzyme activity was nearly restored when testosterone propionate was given once daily for 7 days after cisplatin treatment. Based on these results, it is reasonable to postulate that cisplatin indirectly decreases the microsomal enzyme activity which is regulated by androgens, by causing a significant decrease of the testosterone level in serum of male rats.

Alcohol Oxidoreductases↗
PubMed1996

[Sarcoidosis in an 82-year-old woman who presented with ocular symptoms].

An 82-year-old woman with blurred vision consulted an ophthalmologist. She was admitted to the hospital (internal medicine) for further examination because of uveitis and cataracts. A chest X-ray film and a CT scan showed interstitial infiltration in the right middle lung field, and a Ga-scintigram showed abnormal accumulation in the same area. The mediastinal lymph nodes were not swollen, and the left lung appeared to be normal. We diagnosed her illness as sarcoidosis because the CD4/CD8 of bronchoalveolar lavage fluid from the right B4 was greater than 5.0 and because examination of a specimen obtained by transbronchial lung biopsy from the right B4 showed many non caseous epithelioid granulomas. In contrast bronchoalveolar lavage fluid from the left B4 had a CD4/CD8 of less than 2.0 and examination of a biopsy specimen from the left B4 showed normal lung tissue. The lesion in this patient was only in the right lung, and was classified as Stage 3. However, because the lung fibrosis and the reduction in pulmonary function were minimal, the disease in this case did not fit the conventional classification into stages.

Aged↗
PubMed1995

Purification, characterization, and cDNA cloning of a 27-kDa lectin (L10) from horseshoe crab hemocytes.

We separated granular components of horseshoe crab hemocytes by a combination of centrifugation on sucrose density gradient and high performance liquid chromatography, and a 27-kDa protein termed L10 was found to be a major component in the large granules (Shigenaga, T., Takayenoki, Y., Kawasaki, S., Seki, N., Muta, T., Toh, Y., Ito, A., and Iwanaga, S. (1993) J. Biochem. (Tokyo) 114, 307-316). In the present work, lectin activity of this protein and its unique primary structure were elucidated. L10 was purified by four steps of chromatography, including dextran sulfate-Sepharose CL-6B, CM-Sepharose CL-6B, Sephacryl S-200, and Mono S. At least three 27-kDa isoproteins, named L10a, L10b, and L10c, were isolated. Their amino acid compositions were almost indistinguishable, and there were no amino sugars. All the isoforms had hemagglutinating activity against human A-type erythrocytes, in a Ca(2+)-independent manner with L10b showing the highest activity. The L10b-mediated hemagglutination was inhibited in the presence of N-acetylglucosamine or N-acetylallolactosamine, and the association constant (Ka) between L10b and N-acetylglucosamine was 1.95 x 10(4) M-1. Furthermore, L10b specifically agglutinated Staphylococcus saprophyticus KD. Ultracentrifugation analysis revealed that L10b is present in monomer form in solution. A cDNA coding for an isoform of L10 was isolated from a hemocyte cDNA library. The open reading frame of the 768-base pair cDNA coded for the signal sequence of 19 residues. The mature protein had 236 residues with the calculated molecular weight of 26,757. Amino acid sequences of the peptides derived from L10c exactly corresponded to the predicted sequence of the cDNA, whereas amino acid replacements of Ile-129 to Val and His-213 to Tyr existed both in L10a and L10b, suggesting that the cDNA codes for L10c. Cysteine was absent and there were five tandem repeats with 47 amino acids in each segment with internal sequence identities of 49-68%. The entire amino acid sequences had no significant sequence similarity with other known proteins.

Agglutination Tests↗
PubMed1995

Human pancreatic phospholipase A2 stimulates the growth of human pancreatic cancer cell line.

Phospholipase A2 (PLA2) from human pancreas, designated hPLA2-I, functions as a digestive enzyme. Interestingly, the present study demonstrated that the mature form of hPLA2-I stimulated the growth of a human pancreatic cancer cell line MIAPaCa-2, whereas the pro-form was ineffective. PLA2s from Laticauda semifasciata fraction I, Crotalus adamanteus venom, Streptomyces violaceoruber and bee venom, showed no proliferative effect to the growth of MIAPaCa-2. The Scatchard plot analysis revealed that the MIAPaCa-2 cell had a specific binding site for the mature hPLA2-I. The equilibrium binding constant (Kd) and the maximum binding capacity (Bmax) were 2.6 nM and 0.4 fmol/10(6) cells, respectively. These results suggest that the mature hPLA2-I, but not the pro-form, may function as a growth factor of pancreas carcinoma via the specific binding site.

Bee Venoms↗
PubMed1995

Inositol 1,4,5-trisphosphate binding to porcine tracheal smooth muscle aldolase.

A cytoskeletal fraction of porcine tracheal smooth muscle (PTSM) was found to contain > 90% of total cellular aldolase (fructose 1,6-bisphosphate aldolase, EC 4.1.2.13) activity. PTSM aldolase was purified by DEAE and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) affinity chromatography and found to react with an antibody directed against human aldolase C, but not anti-aldolase A and B. The molecular mass of native aldolase was about 138 kDa (on Sephacryl S-300); SDS-denatured enzyme was 35 kDa (comigrated with rabbit skeletal muscle aldolase). Total cellular aldolase tetramer (aldolase4) content was 34.5 pmol/100 nmol lipid P(i). Ins(1,4,5)P3) binding activity coeluted with aldolase during Sephacryl 300, DEAE, and Ins(1,4,5)P3 affinity chromatography. Ins(1,4,5)P3 bound to purified aldolase (at 0 degree C) in a dose-dependent manner over the range [Ins(1,4,5)P3] 20 nM to 20 microM, with maximal binding of 1 mol of Ins(1,4,5)P3/mol aldolase4 and a Kd of 12-14 microM. Fru(1,6)P2 and Fru(2,6)P2 displaced bound Ins(1,4,5)P3) with a 50% inhibition at 30 and 170 microM, respectively. Ins(1,3,4)P3 (20 microM) and glyceraldehyde 3-phosphate (2 mM) were also potent inhibitors of Ins(1,4,5)P3 binding, but not inositol 4-phosphate or inositol 1,4-bisphosphate (20 microM each). Aldolase-bound Ins(1,4,5)P3 may play a role in phospholipase C-independent increases in free [Ins(1,4,5)P3].

Animals↗
PubMed1995

A novel type of limulus lectin-L6. Purification, primary structure, and antibacterial activity.

Lipopolysaccharide (LPS)-binding protein(s) was first screened in the detergent extract of horseshoe crab (limulus) hemocytes using LPS-immobilized agarose. A protein, designated L6 (M(r) = 27,000), was found to bind to LPS-agarose and was eluted with EDTA or o-phenanthroline. The L6 protein, however, did not inhibit the LPS-mediated activation of a limulus serine protease zymogen factor C. L6 had an affinity to the matrix of Sepharose CL-6B itself, and it could be eluted with high concentrations of monosaccharides (0.5-1.0 M), such as glucose, mannose, and galactose, suggesting a lectin-like nature. The entire amino acid sequence of L6 was determined by sequencing peptides derived from CNBr and enzymatic cleavages. L6 contained 7 half-cystines, and 1 cysteine residue at position 201 had a free SH-group. In addition, positions of the remaining three intrachain disulfide bonds were assigned by amino acid and sequence analyses of three cystinyl peptides produced by lysyl endopeptidase digestion. These results indicated that the entire sequence of L6 consisted of 221 residues with no N-linked sugar and was composed of six tandem repeats, each consisting of 33-38 amino acid residues. Inductively coupled plasma spectrometry of L6 indicated the presence of 0.75 mol zinc/mol of protein. No significant sequence homology was observed between L6 and other proteins, including various animal lectins and LPS-binding proteins. However, L6 showed agglutinating activity on LPS-coated sheep erythrocytes and Gram-negative and Gram-positive bacteria, it inhibited the growth of Gram-negative bacteria, and thus it presumably recognizes carbohydrate components in the cell wall of bacteria.

Amino Acid Sequence↗
PubMed1995

D-myo-inositol 1,4,5-trisphosphate analogues substituted at the 3-hydroxyl group.

D-myo-Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) analogues derived at 3-OH with a bulky substituent were chemically synthesized and structural features of vicinity surrounding the 3-OH of Ins(1,4,5)P3, recognized by metabolic enzymes and by the receptor were explored. 3-Benzoyl-, 3-methylbenzoyl- and 3-para-aminobenzoyl-Ins(1,4,5)P3 inhibited the dephosphorylation of [3H]Ins(1,4,5)P3 by the 5-phosphatase present in erythrocyte ghosts, but the potency varied. The inhibitory potency for the former two compounds was slightly lower than that for Ins(1,4,5)P3, while that for the latter compound was higher. Transfer of the amino group to the meta-position of the benzoyl group led to a less potent analogue. In an assay of [3H]Ins(1,4,5)P3 3-kinase at a low Ca2+ concentration, catalyzed by rat brain cytosol, 3-meta-aminobenzoyl-Ins(1,4,5)P3 was the most potent among compounds examined, including Ins(1,4,5)P3 in inhibiting the phosphorylation, whereas both 3-benzoyl- and 3-methylbenzoyl-Ins(1,4,5)P3 at concentrations up to 30 microM, were without effect. All analogues examined were effective in inhibiting [3H]Ins(1,4,5)P3 binding to purified Ins(1,4,5)P3 receptor, but all 3-derived analogues were less potent and 3-benzoyl-Ins(1,4,5)P3 was the least potent. It would thus appear that the space in the vicinity surrounding the 3-hydroxyl group of Ins(1,4,5)P3 is sterically restrictive with regard to recognition by metabolic enzymes and the receptor, whereas the amino group providing arms for either the electrostatic interaction or the hydrogen bond, makes the analogues more potent.

Calcium Channels↗
PubMed1995

Sexual transmission of human T-lymphotropic virus type I among female prostitutes and among patients with sexually transmitted diseases in Fukuoka, Kyushu, Japan.

The authors investigated the prevalence of antibody to human T-lymphotropic virus type I (anti-HTLV-I) in 409 female prostitutes, 446 patients with an episode of sexually transmitted diseases, and 17,345 control blood donors. All subjects were Japanese and all studies were done in Fukuoka, Kyushu, Japan, in 1989. The prevalence of anti-HTLV-I was significantly higher in the prostitutes (5.1%, p < 0.001), in the male patients (2.8%, p < 0.05), and in the female patients (5.7%, p < 0.05) than in the controls (males 1.4%, females 2.2%). Prevalence of anti-HTLV-I in the prostitutes increased with the number of years spent in prostitution, but the increase was not statistically significant. Among the subjects with sexually transmitted diseases, female prostitutes with syphilis, male patients with non-gonococcal urethritis, female patients with syphilis, and female patients with gonorrhea had a significantly higher prevalence of anti-HTLV-I than did the controls. A longitudinal study was done on the 168 prostitutes. Two (1.3%) of the 158 initially seronegative subjects seroconverted over the period of 2 years. These data suggest that the risk of male-to-female transmission of HTLV-I through sexual contact is high among high risk groups in Japan, and they support the possibility of female-to-male transmission of HTLV-I.

Adolescent↗
PubMed1995

Involvement of the central nervous system in vibration syndrome.

In order to clarify the involvement of the central nervous system (CNS) in vibration syndrome (VS), patients with VS and age-matched controls were given a questionnaire and neurophysiological tests on auditory brainstem response (ABR), event-related potential (P300), short-latency somatosensory evoked potentials (SLSEP), and blink reflex (BR). Twenty-eight patients with a mean age of 56.3 (SD = 3.01, range 48-65) years from western Japan were examined. They had been on sick leave for an average of 6.13 (SD = 3.2, range 1-13) years at the time of the testing. Almost all were experiencing Raynaud's phenomenon in the winter of 1990-1991. They were not suffering from diseases or injuries which might have affected the CNS function. These patients were divided into two subgroups, one with more symptoms related to the CNS, especially memory and judgment (n = 13, group A), and the other with fewer symptoms (n = 15, group B). Normal controls with an average age of 55.8 (SD = 4.8, 48-65) years were people from the same area who met similar criteria. The ABR parameters of the patients were slightly, but not significantly, delayed compared with those of the controls. The SLSEP and BR parameters of the patients were not delayed. The latencies of P300 in group A were significantly delayed compared with those in the controls. The findings suggest that VS involves the cognitive and attention functions of the cerebral higher function, but not the conduction function in the auditory and somatosensory ascending tract and facial nerve reflex tract in the brainstem.

Central Nervous System↗
PubMed1995

Correlation between lead in plasma and other indicators of lead exposure among lead-exposed workers.

In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary delta-aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.

Adult↗
PubMed1995

Evaluation of radioiodinated iodoclorgyline as a SPECT radiopharmaceutical for MAO-A in the brain.

An in vivo estimation of the newly synthesized MAO-A specific inhibitor, [125I]-labeled N-[3(2,4-dichloro-6-iodophenoxy)propyl]-N-methyl-2- propynylamine ([125I]-iodoclorgyline), was performed. Retention of the radioactivity of this radioligand was observed in the brain from 1 h post-injection. Pretreatments with clorgyline and l-deprenyl showed selective binding of [125I]-iodoclorgyline to MAO-A in the brain at 24 h post-injection. Moreover, a good correlation (r = 0.907) between the uptake of [125I]-iodoclorgyline and MAO-A enzyme activity in the cortex was observed in the pretreatment study with several doses of clorgyline. Although improvement to increase the brain/blood ratio is desirable because of slow blood clearance of the radioactivity, radioiodinated iodoclorgyline may serve as a useful SPECT radiopharmaceutical for quantitative analysis of MAO-A in the brain.

Animals↗
PubMed1995

Induction of cytochrome P-450 isoenzymes in cultured monkey hepatocytes.

The effect of phenobarbital (PB), beta-naphthoflavone (beta-NF) and rifampicin (Rif) on the drug-metabolizing activity of cultured squirrel monkey hepatocytes was examined. The drug metabolizing activity (e.g. alkoxycoumarin dealkylase or steroid hydroxylase) gradually decreased during the culture period with 40-70% activity remaining at 72 hr. When 0.5 mM PB was added to the culture, the activities of 7-methoxycoumarin O-demethylase (MCOD) and 7-ethoxycoumarin O-deethylase (ECOD) increased to 6-7 fold higher level than those of control at 72 hr. Testosterone 6 beta-hydroxylase (6 beta-OH-T) and testosterone 16 beta-hydroxylase (16 beta-OH-T) activities were approx. 3-fold higher than those of the control. Addition of beta-NF significantly increased the activities of 7-ethoxyresorufin O-deethylase (EROD) and ECOD. Though statistically insignificant, Rif slightly increased 6 beta-OH-T activity. Western blot analysis indicated PB induced production of the CYP 2B and 3A subfamilies, while beta-NF and Rif induced that of the CYP 1A and the CYP 3A subfamily, respectively.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1995

Anti-microbial activity of human CAP18 peptides.

BACKGROUND: CAP18 derived from rabbit leukocytes is a 142-amino acid protein recently demonstrated to have Lipopolysaccharide (LPS) binding and anti-microbial activity. The C-terminal 37 amino acids of rabbit CAP18 (CAP18(106-142) comprise the LPS-binding and anti-microbial domain. The homologous domain of human CAP18 (huCAP18(104-140) was identified from the recently cloned human CAP18 cDNA. OBJECTIVES: To evaluate the antimicrobial activity of C-terminal peptides derived from human CAP18. STUDY DESIGN: Prepare synthetic human CAP18(104-140) and study anti-microbial activity versus various gram-negative and gram-positive bacteria. RESULTS: Synthetic human CAP18(104-140) has broad anti-microbial activity versus both gram-positive (IC50 = 2.5 micrograms/ml) and gram-negative bacteria (IC50 = 0.5-5 micrograms/ml). Susceptible strains include Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium. A 32-amino acid peptide lacking five amino acids from the C-terminus of CAP18(104-140) has higher activity. Unlike previously characterized anti-microbial peptides derived from granulocyte proteins, CAP18(104-140) is active in serum. CONCLUSIONS: Human CAP18(104-140) or a derivative peptide may have therapeutic potential for bacterial sepsis.

Amino Acid Sequence↗
PubMed1995

Higher expression levels of alternatively spliced pX mRNA in human T lymphotropic virus type I asymptomatic carriers positive for antibodies to p40tax protein.

cDNA of human T lymphotropic virus type I (HTLV-I) pX gene mRNA expressed in peripheral blood lymphocytes of asymptomatic carriers was sequenced. One cDNA clone contained a novel splicing acceptor site, indicating an unidentified form of pX mRNA: pX delta 17 delta 37. All 21 asymptomatic carriers expressed some level of alternatively spliced pX mRNA (pX, pX delta 17, p21rex, orfII, or pX delta 17 delta 37). pX and pX delta 17 were the dominant mRNA species among the five pX mRNAs. All pX mRNAs but orfII correlated significantly with amounts of provirus DNA (P < .05). Levels of provirus DNA and pX mRNAs were significantly higher in anti-p40tax-positive carriers than in negative ones. These observations suggest that the pX mRNAs are expressed ubiquitously, with a complex pattern of splicing, and that the presence of anti-p40tax may serve as a marker for a higher virus load and viral replication levels in asymptomatic HTLV-I carriers.

Aged↗