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Biomedical subjects

H Okuno

Publications and source records attributed to H Okuno.

At least 19 recordsLinked to original sources
PubMed2006

Genotyping of congenital adrenal hyperplasia due to 21-hydroxylase deficiency presenting as male infertility: case report and literature review.

We describe here two infertile male patients who were referred to our hospital with azoospermia at the ages of 33 and 30 years, respectively. Hormonal examinations led to a diagnosis of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency in both patients. Genotyping revealed that the patients had a homozygous I172N and a heterozygous compound I172N/IVS2-13A/C>G mutation, respectively. Glucocorticoid replacement therapy succeeded in improving the seminal status of one patient, but not the other. For the latter patient and his wife, a pregnancy was achieved by testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI) following genetic counseling. It is important to investigate genotyping and to classify patients on the basis of genotypic information in order to arrive at better treatment strategies for male infertility; especially in counseling of TESE-ICSI.

Adrenal Hyperplasia, Congenital↗
PubMed2005

Shortening of distal motor latency in anode distal stimulation.

OBJECTIVE: Distal motor latency (DML) is shortened when the anode is held distally instead of the cathode by increasing the stimulus intensity. The objective of this study was to clarify the mechanism responsible for this shortening. METHODS: In seven healthy subjects, compound muscle action potential (CMAP) was obtained from the thenar muscle by bipolar stimulation of the median nerve at the wrist, and the intensity at which the first motor units were stimulated was defined as the threshold. Bipolar stimulation with extended interpole distance was employed to identify the generating site of the CMAP and F-wave. RESULTS: The shortening of DML was dependent on the stimulus intensity and threshold. For the low threshold condition, the CMAP generating site was replaced from the proximal cathodal pole to the distal anodal pole by increasing the stimulus intensity. The generating site of the F-wave remained at the proximal cathodal pole irrespective of stimulus intensity. CONCLUSIONS: Replacement of the generating site results in the shortening of DML. When the F-wave is recorded after being induced by anode distal stimulation, CMAP should not be simultaneously evaluated. SIGNIFICANCE: This study clarified the generation sites of CMAP and the F-wave when induced by anode distal stimulation.

Action Potentials↗
PubMed2003

Measurement of positron production efficiency from a tungsten monocrystalline target using 4- and 8-GeV electrons.

Intense positron sources are being widely investigated for the next-generation linear colliders and B factories. A new method utilizing an axially oriented crystal as a positron-production target is one of the bright schemes, since it provides a powerful photon source through channeling and coherent bremsstrahlung processes when high-energy electrons penetrate the target. A series of positron-production experiments with tungsten crystals hit by 4- and 8-GeV single-bunch electron beams were carried out at the KEKB 8-GeV injector linac. Three tungsten crystals with different thicknesses (2.2, 5.3, and 9.0 mm) and those combined with amorphous tungsten plates were tested on a precise goniometer. The positron-production yields were measured with a magnetic spectrometer in the positron momentum (P(e(+))) range from 5 to 20 MeV/c. The angle of the <111> crystal axis with respect to the electron-beam direction was controlled by measuring the relative intensities of the produced positrons as a function of the rotational angle of the goniometer. The results show that the enhancements of the positron yield from crystal targets compared to amorphous targets of the same thickness at P(e(+))=20 MeV/c are from 1.5 to 3.7 and from 1.8 to 5.1, depending upon the target thickness for 4- and 8-GeV electrons, respectively.

Journal Article↗
PubMed2003

Practical assay and molecular mechanism of aggregation inhibitors of beta-amyloid.

Beta-Amyloid peptide (Abeta) is the main protein component of neuritic plaques in the brain of patients of Alzheimer's disease (AD), and its neurotoxicity would be exposed by the formation of aggregates. The aggregation inhibitors composed of an Abeta recognition element (KLVFF) and a hydrophilic moiety are evaluated by a novel fluorescence assay. These compounds inhibit growth of the model aggregates on the KLVFF immobilized surface. In addition, some compounds also possess disrupting activities of preformed aggregates. These compounds could be a key candidate for therapeutic drugs for AD by their novel molecular mechanisms.

Amino Acid Sequence↗
PubMed2002

Sonolysis of surfactants in aqueous solutions: an accumulation of solute in the interfacial region of the cavitation bubbles.

The sonolysis of surfactants (such as sodium dodecylbenzenesulfonate (DBS), sodium dodecylsulfate (SDS), and polyethylene glycol monostearate), sodium 4-toluenesulfonate (STS), and 1-hexanol in aqueous solutions was investigated under an argon atmosphere with ultrasound of 200 kHz in order to compare the scavenging efficiency of the hydroxyl radical and the accumulation in the gas-liquid interfacial region of the cavitation bubbles. The degradation rate of the solute follows the order 1-hexanol > DBS and SDS > STS. The scavenging efficiency of the hydroxyl radical by non-volatile surfactants was much greater than that of the non-volatile and hydrophilic solute (e.g., STS). The surfactant was accumulated in a relatively high ratio in the interfacial region. The degradation of surfactants occurred by reaction with the hydroxyl radical and also by pyrolysis at high temperature. On the other hand, STS, due to its non-volatile and hydrophilic properties, was principally present in the bulk solution and the degradation by pyrolysis was not observed at the investigated concentration ranges.

Journal Article↗
PubMed2001

Mononuclear platinum(II) complex with 2-phenylpyridine ligands showing high cytotoxicity against mouse sarcoma 180 cells acquiring high cisplatin resistance.

Mouse sarcoma 180 cell with a 25-fold higher cisplatin (CDDP) resistance, termed S-180cisR, is newly established. S-180cisR cells grow quite slowly in the presence of CDDP with high concentration. This may show that S-180cisR cells modulate the cell cycle to acquire CDDP resistance. P-Glycoprotein is selectively expressed on the surface of S-180cisR, which is not on CDDP-sensitive S-180 parent cells. In an experiment using an inhibitor (verapamil) of P-glycoprotein, cytotoxicity of CDDP against S-180cisR is significantly increased (viz., IC(50) value is decreased) and accumulation of CDDP in S-180cisR cells is also increased. These results indicate that enhanced pumping-out of CDDP by P-glycoprotein should be one of the reasons for the CDDP resistance of S-180cisR. A platinum(II) complex with a cyclometalated 2-phenylpyridine ligand and a nonchelated one (complex 5) is synthesized, and its structure is determined by X-ray structural analysis. Complex 5 has a cyctotoxicity against S-180cisR higher than that of CDDP and its derivatives with 2- or 3-substituted pyridine ligands (complexes 2-4, 6, 7). Complex 5 is incorporated in S-180cisR to an enormously greater extent than CDDP; that is, the ratio of accumulated platinum amount after 3 h is 61.9. In S-180 parent cells, on the other hand, the ratio remains 8.1. This high accumulation of complex 5 into S-180cisR must account for the higher activity of complex 5 against S-180cisR compared to CDDP.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Spatiotemporal dynamics of brain-derived neurotrophic factor mRNA induction in the vestibulo-olivary network during vestibular compensation.

Vestibular compensation, which is the behavioral recovery from vestibular dysfunction produced by unilateral labyrinthectomy (UL), is attributed to functional and structural reorganization of neural networks in the central vestibular system. To assess the possible contribution of brain-derived neurotrophic factor (BDNF) to this recovery process, we investigated changes in mRNA expression levels in the central vestibular system after UL. We evaluated BDNF mRNA expression levels by quantitative reverse transcription-PCR and in situ hybridization. We found that BDNF mRNA is differentially induced in the medial vestibular nucleus ipsilateral to UL and in the prepositus hypoglossi and inferior olive on the contralateral side. The BDNF mRNA induction lasted for at least 24 hr and returned to the basal expression level within 72 hr after UL. In contrast to BDNF mRNA induction, the expression of an immediate-early gene, c-fos, quickly reached the maximum level at 3 hr and decreased to the basal level within 24 hr after UL. Neither BDNF or c-fos induction was observed in sham-operated animals. The persistent induction of BDNF after UL temporally corresponded to early behavioral manifestations of vestibular compensation. We further found that trkB mRNA was expressed in the central vestibular network at high levels, although its expression levels did not change over time after UL. Because BDNF is implicated in regulating synaptic structure and function, these results provide support for the hypothesis that BDNF is involved in neuronal reorganization that allows vestibular compensation.

Adaptation, Physiological↗
PubMed2001

Sonochemical degradation of chlorinated hydrocarbons using a batch and continuous flow system.

The sonochemical degradation of chlorinated hydrocarbons such as 1,1,1-trichloroethane, trichloroethylene and tetrachloroethylene in aqueous solution was carried out in the batch and continuous flow systems at an ultrasonic frequency of 100kHz under an air atmosphere. In the batch experiment, the rate of degradation follows the order 1,1,1-trichloroethane>tetrachloroethylene>trichloroethylene, and the chlorinated hydrocarbon were readily degraded by ultrasonic irradiation. The experiments in the continuous flow system were performed in the range of volumetric flow rate from 7 to 30 x 10(-3)lmin(-1). The conversion of the chlorinated hydrocarbons at a steady-state of reactor depended on the volumetric flow rate. The yield of Cl(-) (as a measurement of mineralization of chlorinated hydrocarbons) was 70-90% of the chlorine atoms in the parent chlorinated hydrocarbon molecules. From the viewpoint of the scale-up process, the sonochemical degradation of trichloroethylene was simulated in a three stage reactor, and the conversion (>99%) in a third stage reactor was showed the good results that can be satisfied a desired water quality standard.

Environmental Pollution↗
PubMed2001

Differential induction of brain-derived neurotrophic factor mRNA in rat inferior olive subregions following unilateral labyrinthectomy.

Vestibular compensation, the neuronal process underlying behavioral recovery from vestibular dysfunction produced by unilateral labyrinthectomy, is attributed to functional reorganization of neuronal circuits in the brainstem and cerebellum. Climbing fibers originating from the inferior olive are suggested to play a crucial role in this compensatory process. To assess the possible contribution of brain-derived neurotrophic factor (BDNF) to the function of climbing fibers during vestibular compensation, we investigated the BDNF mRNA expression in the rat inferior olive after unilateral labyrinthectomy by quantitative in situ hybridization. We found several induction patterns depending on the subregions of the inferior olive 6 h after unilateral labyrinthectomy. First, in the dorsal cap and the ventrolateral outgrowth, the expression levels increased on the side contralateral to the lesion and decreased on the ipsilateral side. Second, in the beta nucleus, C subnucleus of the medial accessory olive, and A/B subnuclei of the medial accessory olive, we detected an increase in the mRNA expression level on the side contralateral to the lesion, but no changes in the expression level on the ipsilateral side. In the beta nucleus, where the strongest induction was observed, the mRNA expression level increased nearly five-fold. Third, in the dorsomedial cell column, the mRNA expression levels increased on both sides. Finally, we did not detect significant changes in mRNA expression levels in the other subregions of the inferior olive, the dorsal accessory olive, principal olive and rostral medial accessory olive. The changes in BDNF mRNA expression reverted to control levels by 72 h after the labyrinthectomy. The inferior olive subregions that showed changes in BDNF mRNA expression levels send climbing fibers to the cerebellar cortical regions that, in turn, project to the vestibular nuclei. Therefore, BDNF induced in these subregions could contribute to the functional reorganization of the olivo-cerebellar system for vestibular control.

Animals↗
PubMed2001

Preparation of platinum nanoparticles by sonochemical reduction of the Pt(IV) ions: role of surfactants.

Sonochemical reduction processes of Pt(IV) ions in water have been investigated in the presence of various kinds of surfactants such as sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate (DBS) as anionic surfactants, and polyethylene glycol monostearate (PEG-MS) as non-ionic, dodecyltrimethylammonium chloride (DTAC) and bromide (DTAB) as cationic surfactants. An improved colorimetric determination reveals that Pt(IV) ion is reduced to zero valent metal in two steps: step (1)--Pt(IV) ion to Pt(II) ion, and step (2)--Pt(II) ion to Pt(0), and after the completion of step (1), step (2) sets in. It appears that rapid scrambling reactions among platinum ions and/or atoms, that is, Pt(I) + Pt(IV)-->Pt(II) + Pt(III), etc. take place. In the sonolysis of aqueous solutions of SDS, DBS or PEG-MS, two kinds of organic reducing radicals, R(ab) and R(py), are proposed to contribute to the reduction. Radical R(ab) is formed from the reaction of the surfactants with primary radicals such as hydroxyl radicals and hydrogen atoms originated from the sonolysis of water, and radical R(py) is formed from the direct thermal decomposition of surfactants in the interfacial region between the collapsing cavities and the bulk water. R(ab) is effective for both the reduction steps, whereas R(py) is involved only in the reduction step (1). This fact coincides with the previous reported sonochemical reduction of Pt(II) ions. Hydrogen atoms themselves scarcely participate in the reduction. The average diameter (1.0 nm) of platinum particles prepared from the system of PEG-MS is smaller than those from the aqueous solution of anionic surfactant SDS (3.0 nm) and DBS (3.0 nm).

Journal Article↗
PubMed2001

Identification of the molecular interaction site of amyloid beta peptide by using a fluorescence assay.

Beta-amyloid peptides (Abeta) are the main protein components of neuritic plaques and are important in the pathogenesis of Alzheimer's disease. It is reported that Abeta itself is not toxic; however, it becomes toxic to neuronal cells once it has aggregated into amyloid fibrils by peptide-peptide interactions. In this study, to specify the molecular mechanism of aggregation, a novel fluorescence assay was designed. For this purpose, possible partial peptides (38 types of 5-mer) were synthesized on solid-phase. The molecular interactions were examined by a fluorescence probe possessing Lys-Leu-Val-Phe-Phe (KLVFF) as a molecular recognition site. KLVFF is known to be a minimum sequence for formation of the Abeta aggregate. A specific interaction was observed between labeled and immobilized KLVFF. It suggests that the aggregation of Abeta was controlled by the recognition of KLVFF itself by hydrophobic and electrostatic interactions.

Alzheimer Disease↗
PubMed2001

Expression of Apg-1, a member of the Hsp110 family, in the human testis and sperm.

BACKGROUND: Apg-1 encodes a heat shock protein belonging to the Hsp110 family and is inducible by a 32 degrees C to 39 degrees C heat shock in somatic cells. In mouse testicular germ cells Apg-1 mRNA is constitutively expressed depending on the developmental stage. As human Apg-1 has recently been identified, the expression of Apg-1 in the human testis and sperm was investigated. METHODS: Expression and heat-inducibility of Apg-1 in the human testicular germ cell tumor cell line, NEC8, was analyzed. Using an antimouse Apg-1 antibody, expression of Apg-1 in the human testis and sperm was examined by western blotting after confirmation of the specificity of the antibody. The cells expressing Apg-1 in the testis were further determined by immunohistochemistry. RESULTS: Slight induction of Apg-1 mRNA was detected in NEC8 cells after 32 degrees C to 39 degrees C temperature shift. In the human testis, the antibody specifically recognized Apg-1, which was absent in the testis without germ cells (Sertoli-cell-only syndrome) or arrested at spermatogonia. Spermatocytes and spermatids, but not testicular somatic cells, were positively stained with the anti-Apg-1 antibody. By western blot analysis, Apg-1 was detected in the preparation enriched for sperm from normal volunteers and infertile patients, but not from azoospermia patients. CONCLUSION: Apg-1 is developmentally expressed in human testicular germ cells and sperm, suggesting its role in spermatogenesis and fertilization. Identification of substrates for Apg-1 chaperone activity will help elucidate its function.

Adult↗
PubMed2001

[Progression from adenocarcinoma to small cell carcinoma of the prostate during endocrinotherapy: a case report].

A 72-year-old man had undergone surgical castration for metastatic prostate cancer (stage D2, the PSA value was 4,300 ng/ml) in September, 1997. He was well clinically for 16 months with undetected level of PSA. However, he presented with general malaise and gross hematuria in May, 1999. After admission to our hospital his condition rapidly deteriorated and he died one week later with respiratory failure. Autopsy revealed extensive involvement of the prostate and bladder by solid tumor with multiple metastases in lungs, liver, spleen, kidneys and bone. Histological examination revealed pure small cell carcinoma of the prostate.

Adenocarcinoma↗
PubMed2000

Selective synthesis and kinetic measurement of 1:1 and 2:2 cyclic compounds containing 1,4,7,10-tetraazacyclododecane and azobenzene units

1:1 cyclic compounds 8a-c (51-55%) and 2:2 cyclic compounds 9a-c (20-49%) containing 1,4,7,10-tetraazacyclododecane (cyclen) and azobenzene units were selectively synthesized under UV irradiation (330 nm < lambda < 380 nm) and in the dark. Synthesis depended on the wavelength of irradiation light and the length of methylene chains of the linker between the cyclen and azobenzene units. A study of NMR and UV-vis spectra indicated that properties of 8a-c and 9a-c are closely related to their structural flexibility. Rate constants (k) and thermodynamic parameters (DeltaG(), DeltaH(), and DeltaS()) of 8a-c and 9a-c were studied in nonpolar media (benzene) and polar media (methanol). The cis to trans isomerization rates in the dark for these cyclic compounds increase with ring size or structural flexibility (8a < 8c < 8b < 9a < 9b < 9c). In principle, DeltaS() dominates DeltaG() in cyclic compounds.

Journal Article↗
PubMed2000

Molecular diagnosis of metastatic origin in a patient with metachronous multiple cancers of the renal pelvis and bladder.

It is not uncommon for patients with urothelial cancer to have synchronous and metachronous multifocal invasive tumors of the bladder and upper urinary tract. If a metastatic lesion becomes evident in such a patient, the origin of the metastasis is often not determinable using conventional histopathologic examination of the surgical or autopsy specimen. Here, we report a patient in whom the clonal relationship among the histologically undistinguishable multifocal urothelial cancers and metastatic tumors could be clarified by molecular genetic analysis. Furthermore, the potential role for each genetic alteration in the multifocal and metastatic tumor development and the treatment efficacy for each multifocal tumor were also clearly demonstrated.

Carcinoma, Transitional Cell↗
PubMed2000

Myosin light chain phosphorylation and Mn2+-dependent acetylcholine-induced contractions in guinea pig vas deferens.

We have reported that noradrenaline but not K+ induced a sustained and dose-dependent contraction without extracellular Ca2+ and Mn2+ in Ca2+-depleted Mn2+loaded vas deferens from the guinea pig. The Mn2+dependent noradrenaline-induced contractions developed without an increase in phosphorylation of 20-kDa myosin light chain. To clarify whether such an unusual Mn2+dependent contraction was induced only by noradrenaline or not, we examined effects of acetylcholine on Ca2+-depleted Mn2+-loaded guinea pig vas deferens. Acetylcholine (1 microM(-1) mM) induced a sustained dose-dependent contraction without extracellular Ca2+ or Mn2+. W-7 (10 microM or 100 microM) and wortmannin (1 microM) both reduced the Mn2+dependent acetylcholine-induced contractions similarly to Ca2+-dependent acetylcholine-induced contractions in isolated vas deferens without either Ca2+ depletion or Mn2+ loading. However, the Mn2+-dependent acetylcholine-induced contractions developed without a significant increase in the phosphorylation of the myosin light chain determined by urea-glycerol polyacrylamide gel electrophoresis and immunoblotting. These results indicate that acetylcholine as well as noradrenaline induces Mn2+-dependent contraction and are consistent with our previous assumption that Mn2+ may preferentially support receptor-mediated contractions in the guinea pig isolated vas deferens. The results also suggest that the activation of myosin light chain kinase is essential for the development of Mn2+-dependent acetylcholine-induced contractions, and that Mn2+ may accelerate formation of non-phosphorylated attached cross-bridges during receptor activation.

Acetylcholine↗
PubMed2000

Preparation of functional liposomes with peptide ligands and their binding to cell membranes.

Two novel lipopeptides, which have the peptide ligands [alpha-melanocyte stimulating hormone (alpha-MSH)] sequence and repeated [Gly-Arg-Gly-Asp-Se (GRGDS) sequence], are designed, synthesized by the solid-phase method, and introduced into liposome membranes by the freeze-thaw method. These liposomes bearing the peptide ligands on their surface are expected to bind to cell membranes. We have confirmed that the lipopeptides are introduced into liposome membranes almost quantitatively, while such a high degree of incorporation has not been accomplished in conventional methods. In this respect, the present method is superior to prepare surface-modified liposomes that are applicable to drug carriers and so on. We have also confirmed by using immunoelectron microscopy that the peptide ligands are actually located in an aqueous phase. It has been shown by flow cytometry that the liposome bearing alpha-MSH peptide ligand binds to B16 cells and the liposome bearing the repeated GRGDS sequence binds to NIH3T3 cells.

3T3 Cells↗