Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 325 records · Page 18Linked to original sources

PubMed1996

Nucleotide sequence of the 5' noncoding region of hepatitis G virus isolated from Japanese patients: comparison with reported isolates.

The nucleotide sequences of the 5' noncoding region (NCR) of hepatitis G virus (HGV) from sera of Japanese patients were determined. Among these isolates, there was a high degree (> 96.9%) of sequence identity, whereas identity with previously reported GB virus-C or HGV strains was low (> 87.0%). Phylogenetic analyses showed that the HGV strains from Japanese patients clustered in groups distantly separated from previously reported strains. Among the Japanese HGV isolates, the genetic distances corresponded to subtype differences observed within hepatitis C virus (HCV) isolates, whereas the differences between the Japanese isolates and the prototypes corresponded to genetic distances observed between HCV genotypes. The Japanese HGV isolates found in this study should be placed in a new genotype distinct from previously described isolates.

Base Sequence↗

PubMed1996

Somatostatin neurons form a distinct peptidergic neuronal group in the rat suprachiasmatic nucleus: a double labeling in situ hybridization study.

Accumulating evidence indicates that somatostatin (SS) is a key substance for the circadian rhythm of rodents. In the present study, we investigated whether SS mRNA coexists with arginine-vasopressin (AVP) mRNA, vasoactive intestinal peptide/peptide histidine isoleucine amide (VIP/PHI) mRNA and glutamate decarboxylase (GAD) mRNA in neurons of the rat suprachiasmatic nucleus (SCN) by double labeling in situ hybridization technique. SS mRNA-positive neurons were scattered in the whole region of rostral SCN, in the intermediate region between dorsomedial and ventrolateral region at the middle level, and in the mid to lateral region at the caudal level. These neurons were located in the close vicinities of the dorsomedial AVP and ventrolateral VIP/PHI mRNA-positive cell clusters. They rarely coexpressed AVP mRNA or VIP/PHI mRNA, but mostly coexpressed GAD mRNA. Thus, SS-synthesizing neurons are GABAergic and form a distinct cell group different from AVP or VIP/PHI cell groups.

Animals↗

PubMed1996

Identification of nasal epithelial cells with carbonic anhydrase activity.

Although carbonic anhydrase (CA) plays an important role in respiration, there is little information about CA in the respiratory system except for the lung. We examined the entire nasal cavity of guinea pig to identify CA activity using an enzyme-histochemical method. CA activity was detected in a group of morphologically distinct nasal epithelial cells. These cells were singly and sparsely distributed mainly in the olfactory epithelium and their number increased rostrocaudally. These cells were also detected in the apical portion of the nasal turbinate, particularly on the nasal endoturbinate, with a more complicated structure, rather than on the nasal septum and the roof of nasal cavity. Although the physiological role of these cells in unknown, based on the morphological and histochemical characteristics and the distribution of these cells, we speculated that they may represent a specialized chemoreceptors.

Animals↗

PubMed1996

Cloning of the cDNA for human IFN-gamma-inducing factor, expression in Escherichia coli, and studies on the biologic activities of the protein.

We have recently reported that a novel molecule, murine IFN-gamma-inducing factor (IGIF) produced by mouse liver cells, possesses potent biologic activities, including the induction of IFN-gamma production by spleen cells and the enhancement of NK cell cytotoxicity. In this paper, we report on the isolation of human IGIF cDNA clones from normal human liver cDNA libraries using murine IGIF cDNA as a probe. The amino acid sequence deduced from the human cDNA clones indicated a 193-amino acid precursor peptide and revealed 65% homology with that of murine IGIF. The amino acid sequence of IGIF also included an IL-1 signature-like sequence. Subsequently, the cloned cDNA was expressed in Escherichia coli, and preliminary studies on the biologic activities of the recombinant protein were performed. The recombinant human IGIF induced IFN-gamma production by mitogen-stimulated PBMC and enhanced NK cell cytotoxicity, in a manner similar to murine IGIF. In addition, recombinant human IGIF also augmented granulocyte-macrophage-CSF production and decreased IL-10 production, but had no effect on IL-4 production by Con A-stimulated PBMC. Based on these pleiotropic effects of IGIF, we propose that this novel cytokine be designated as IL-18.

Adult↗

PubMed1996

Tyrosine hydroxylase-immunoreactive cells in the nodose ganglion for the canine larynx.

Several substances have been reported as candidates for the neurotransmitter in the laryngeal afferent system. In the present study we demonstrated that catecholamine is also a candidate neurotransmitter in the canine laryngeal afferent system using tyrosine hydroxylase (TH) immunochemistry in combination with retrograde labelling with cholera toxin B in subunit-conjugated gold (CTBG). A few cells in the nodose ganglion labelled by application of CTBG to the internal branch of the superior laryngeal nerve were also TH-immunoreactive. These cells were also labelled following application of CTBG to the nucleus of the solitary tract. These results indicate that some of the TH-IR cells in the nodose ganglion could be primary afferent neurones for the canine larynx.

Animals↗

PubMed1996

Nitrergic neurons in the canine intrinsic laryngeal muscle.

Nitrergic ganglionic cells located in the canine intrinsic laryngeal muscle were studied by NADPH-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. Cells intensely stained by NADPH-d histochemistry were found between the striated muscle fibers of the intrinsic laryngeal muscle. Most of these cells were bipolar or pseudounipolar in form. Some NADPH-d negative cells were observed to be enveloped in a mesh by varicose NADPH-d positive nerve fibers. The findings obtained by nNOS immunohistochemistry corresponded well with those obtained by NADPH-d histochemistry, indicating that NADPH-d activity in the ganglion in the intrinsic laryngeal muscle is nNOS. The present findings clearly indicate that some of the ganglion cells located in the canine intrinsic laryngeal muscle are nitrergic, and that the ganglionic cells synapse together with the participation of nitric oxide in integrating ganglionic cells.

Animals↗

PubMed1996

Estrogen receptor (ER) and its messenger ribonucleic acid expression in the genital tract of female mice exposed neonatally to tamoxifen and diethylstilbestrol.

BACKGROUND: Tamoxifen (Tx) is known as an antiestrogen because of its competitive inhibition of estrogen binding to estrogen receptor (ER), and it is used as an estrogen antagonist in the human breast. However, Tx is known to have estrogen agonist activity in the human fetal reproductive tracts and vaginal epithelium and endometrium of postmenopausal women as has been known in the mouse uterus. Therefore, we examined estrogenic potency of Tx on the uterus and vagina in newborn mice and adult ovariectomized mice. METHODS: Using immunohistochemistry and in situ hybridization, we studied changes in expression of ER protein and ER mRNA in the uterus and vagina of C57BL/Tw mice exposed neonatally to 100 micrograms Tx and 0.03-3 micrograms diethylstilbestrol (DES), and changes in expression of ER mRNA in the ovariectomized adult mice given injections of 100 micrograms Tx and 3 micrograms DES. RESULTS: Nuclei of the epithelial and stromal cells in the vagina and of the stromal cells in the uterus showed strong ER immunostaining on the day of birth (= day 0), whereas nuclei of the epithelial cells in the uterus exhibited the ER immunostaining by day 5. In uterine epithelial cells, however, ER was induced by DES, 17 beta-estradiol, testosterone or Tx 24 h after a single injection on day 0, but not by the injection of 5 alpha-dihydrotestosterone, progesterone, or epidermal growth factor. ER in uterine epithelial cells was detected even 12 h after a single injection of 3 micrograms DES on day 0. ER mRNA expression of uterine and vaginal epithelial cells of newborn mice increased 4 h after a single injection of 3 micrograms DES. ER mRNA expression of uterine and vaginal stromal cells in neonatal mice increased 4 h after a single injection of 100 micrograms Tx. In uterine epithelial and stromal cells and vaginal epithelial cells of ovariectomized adult mice, ER mRNA expression increased 12 h after a single injection of 3 micrograms DES and 100 micrograms Tx. CONCLUSIONS: The present study indicates that Tx acts as ER inducer in the uterus and vagina of neonatal and ovariectomized adult mice. However, responsiveness of reproductive tracts to Tx is different between newborn and adult mice.

Animals↗

PubMed1996

Usage of haloperidol for delirium in cancer patients.

Although haloperidol is mainly used for the medical treatment of delirium in cancer patients, there are no universally accepted guidelines for its usage. We accordingly assessed the usefulness in managing delirium of a haloperidol treatment regimen in ten delirious cancer patients. The results of this preliminary study suggest that, in the management of delirium, appropriate usage of haloperidol on the first day is important as it affects the dosage thereafter.

Aged↗

PubMed1996

Histochemical localization of carbonic anhydrase in the trachea of the guinea pig.

Tissue specimens from guinea pigs were examined using an enzyme-histochemical reaction to explore the presence of carbonic anhydrase (CA) activity in the trachea. CA activity was detected in a group of morphologically distinct epithelial cells, in goblet cells, and in glands of the tracheal mucosa. The epithelial cells showing CA activity were distributed singly and sparsely throughout the entire trachea. These cells showed a wide morphological variability and were clearly different from those forming the pseudostratified ciliated epithelium. Their number was higher in sections closer to the tracheal bifurcation than in those near the larynx. Although the nature of these cells is unknown, based on their morphological and histochemical characteristics and their distribution, they may represent a specialized chemoreceptor. To our knowledge, this is the first report of CA localized in tracheal epithelial cells.

Animals↗

PubMed1996

Reserpine-induced immunocytochemical change of neuropeptide Y in the hypothalamic arcuate nucleus.

The effect of reserpine on neuropeptide Y immunoreactive (NPY-IR) neurons in the rat hypothalamic arcuate nucleus was examined by immunocytochemical techniques. Although only NPY-IR fibers and terminals were distributed in this nucleus in untreated and saline treated rats, single treatment of reserpine (10 mg/kg, i.p.) visualized abundant NPY-IR neuronal cell bodies: the increase began at 12 h of postinjection, reached its maximal level at 48 h, and returned to its normal level at 96 h. Pretreatment of nialamide, a monoamine oxidase inhibitor, prevented these acute reserpine-induced changes, suggesting reserpine acts on NPY neurons through monoaminergic mechanism. Chronic treatment of haloperidol (5 mg/kg, once daily for 5 days) a dopamine receptor antagonist, could induce the similar increase of NPY immunoreactivity. However, interruption of adrenergic and serotonergic neurotransmissions by chronic treatment of propranorol and methysergide, or chemical lesions of ascending noradrenergic and serotonergic pathways by 6-hydroxydopamine and 5,6-dihydroxytryptamine, could not induce any immunoreactive increase of NPY in arcuate neurons. These findings strongly suggest that reserpine-induced NPY increase occurs through dopaminergic afferents in hypothalamic arcuate neurons.

Animals↗

PubMed1996

Effects of the synthesized growth hormone releasing peptide, KP-102, on growth hormone release in sodium glutamate monohydrate-treated low growth rats.

KP-102 (D-Ala-D-beta-Nal-Ala-Trp-D-Phe-Lys-NH2), a new second generation hexapeptide, has a potent growth hormone (GH)-releasing action in vivo and in vitro. Here, we evaluated the GH-releasing action of KP-102 under pentobarbital (PB) anesthesia in neonatally sodium-glutamate-monohydrate-treated low growth (NMSG-LG) rats. The plasma GH level in NMSG-LG rats after i.v. administration of KP-102 at 100 micrograms/kg was 1/6.7 (95% C.L. 1/14.7 - 1/3.0) of that in normal rats given the same dose (p < 0.01). However, the increase was significant compared with that in normal rats after saline administration (p < 0.01). The plasma GH releasing action of KP-102 at 100 micrograms/kg i.v. in rats with lesions in the bilateral hypothalamic arcuate nuclei (ARC), was about 1/6.3 (95% C.L. 1/12.4 - 1/3.2) of that in normal rats under PB anesthesia (p < 0.01). When KP-102 was injected into the ARC at doses of 0.0002, 0.02 and 2 micrograms/rat, GH release was dose-related (p < 0.01) under PB anesthesia. KP-102 at 2 micrograms i.c.v. also increased the plasma GH levels (p < 0.01) to about 1/8.3 (95% C.L. 1/22.7 - 1/3.1) of that by systematic administration, at the same potency as the ARC injection (1/13.7 and 95% C.L. 1/37.2 - 1/5.0). These findings suggest that KP-102 potently stimulates the GH release by a direct or indirect antagonism of somatostatin (SRIF) and growth hormone releasing hormone (GHRH) release in the hypothalamus and by a direct action on the pituitary. Furthermore, the GH-releasing action of KP-102 was similar and additive upon both regions in vivo at the maximum effective dose. Moreover, since the GH-release in response to KP-102 administration differed between NMSG-LG and normal rats, and since KP-102 increased the GH release even in NMSG-LG rats, it should be evaluated in the hypophysial GH secretion tests, and may be used to treat the hypophysial GH secretion insufficiency.

Animals↗

PubMed1996

Neurobiology of L-DOPAergic systems.

L-DOPA is proposed to be a neurotransmitter and/or neuromodulator in CNS. It is released probably from neurons, which may contain L-DOPA as an end-product, and/or from some compartment other than catecholamine-containing vesicles. The L-DOPA itself produces presynaptic and postsynaptic responses. All are stereoselective and most are antagonized by competitive antagonist. In striatum, L-DOPA is neuromodulator, mother of catecholamines, not only a precursor for dopamine but also a potentiator of children for presynaptic beta-adrenoceptors to facilitate dopamine release and postsynaptic D2 receptors, and ACh release inhibitor. All may cooperate for Parkinson's disease. Meanwhile, supersensitization of increase in L-glutamate release to nanomolar levodopa was seen in Parkinson's model rats, which may relate to dyskinesia or "on-off" during chronic therapy. In lower brainstem, L-DOPA tonically activates postsynaptic depressor sites of NTS and CVLM and pressor sites of RVLM. L-DOPA is probably a neurotransmitter of primary baroreceptor afferents terminating in NTS. GABA, the inhibitory neuromodulator for baroreflex in NTS, tonically functions to inhibit, via GABAA receptors, L-DOPA release and depressor responses to levodopa. Levodopa inversely releases GABA. L-DOPAergic monosynaptic relay from NTS to CVLM and from PHN to RVLM is suggested. Tonic L-DOPAergic baroreceptor-aortic nerve-NTS-CVLM relay seems to carry baroreflex information. Disturbance of neuronal activity to release L-DOPA in NTS, loss of the activity in CVLM, enhancement of the activity with decreased decarboxylation and increase in sensitivity to levodopa in RVLM may be involved in maintenance of hypertension in SHR. This is a story of "L-DOPAergic receptors" with extremely high affinity and low density.

Afferent Pathways↗

PubMed1996

Evaluation of endometriosis in uterosacral ligaments by transrectal ultrasonography.

Uterosacral ligaments are one of the common targets of pelvic endometriosis, which is usually clinically rather than surgically diagnosed. This study was performed to determine if uterosacral ligaments infiltrated by endometriosis could be detected by transrectal ultrasonography. Uterosacral ligaments in non-endometriosis subjects (n = 64) were observed as low echoic homogeneous arcs in both sides of the uterine cervix. Patients who had endometriosis (n = 29) on the ligaments showed thick and irregularly-shaped uterosacral ligaments by the transrectal ultrasound examination. The results also suggested that the thickness of uterosacral ligaments was associated with the clinical symptoms. Transrectal ultrasonography may provide quantitative information to manage patients with infiltrating endometriosis.

Adult↗

PubMed1996

Follicular development and ovulation in macrophage colony-stimulating factor-deficient mice homozygous for the osteopetrosis (op) mutation.

To clarify the role of macrophages and macrophage colony-stimulating factor (M-CSF) in follicular development and ovulation, the processes of folliculogenesis and ovulation, numerical changes in macrophages, and proliferative capacity of granulosa cells were examined in op/op mice before or after daily M-CSF administration. The natural estrous cycle was determined daily by means of vaginal smears. The number of ovulated ova in both fallopian tubes was significantly smaller in op/op mice than in normal littermates. Such ova markedly increased in number after daily M-CSF administration. The numbers of both antral and mature follicles in the proestrous ovary were markedly lower in op/op mice than in the controls and increased after daily M-CSF administration. Flash-labeling with [3H]thymidine showed that the proliferative capacity of granulosa cells in antral follicles was reduced in op/op mice but elevated after daily M-CSF administration. Numbers of granulosa cells and macrophages in the antral follicles were significantly decreased in op/op mice but were increased after M-CSF treatment. All these data provide evidence that macrophages are implicated in the process of folliculogenesis and ovulation.

Animals↗

PubMed1996

Role of macrophages in ovarian follicular development.

The effects of macrophages on granulosa cell proliferation were examined using gonadotropin-primed immature female rats and osteopetrotic (op/op) mice, a model defective in monocyte-macrophage lineage cells. Macrophages were found in the follicles at various developmental stages in rats and mice. The labeling index with [3H]thymidine of cultured rat granulosa cells was maximal when they were cultured with peritoneal macrophages at a macrophages:granulosa cell ratio of 0.01. This ratio was similar to those in rat preantral and antral follicles in vivo. In op/op mice, the number of developing follicles was markedly reduced, but increased after daily macrophage-colony-stimulating factor (M-CSF) administration. In the antral follicles of op/op mice, both granulosa cells and macrophages were significantly decreased in number but were increased after M-CSF treatment. Double immunohistochemical staining revealed that epidermal growth factor (EGF)-positive cells were macrophages in the developing rat follicles. These findings suggest that macrophages are located in the developing follicles and participate in promoting granulosa cell growth through a paracrine mechanism by secreting EGF and other cytokines.

Animals↗

PubMed1996

Nitrergic innervation of the rat larynx measured by nitric oxide synthase immunohistochemistry and NADPH-diaphorase histochemistry.

We evaluated the involvement of nitric oxide (NO) in the laryngeal innervation of rats using NADPH-diaphorase (NADPH-d) histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. The findings obtained by NADPH-d histochemistry were identical with those obtained by nNOS immunohistochemistry, indicating that NADPH-d is nNOS in the laryngeal innervation system. We found NADPH-d-positive nerve fibers in every region of the larynx. In the epithelia of the mucosa, a small number of NADPH-d-positive nerve fibers were detected. The plexus of NADPH-d-positive nerve fibers was commonly found in the lamina propria, and some of these fibers were clearly associated with blood vessels. We also noted NADPH-d-positive nerve fibers in the region of laryngeal glands. Some of these fibers appeared to terminate in the glandular cells. We found NADPH-d-positive nerve fibers with varicosities in the intrinsic laryngeal muscle and free-ending nerve fibers on the muscle fiber. Motor end plate-like structures were positive for NADPH-d histochemistry. The NADPH-d-positive nerve fibers appeared to terminate at motor end plate-like structures in two of nine rats examined. A cluster of NADPH-d-positive neurons were occasionally present in the lamina propria of the laryngeal mucosa, in the connective tissue between the thyroid cartilage and intrinsic laryngeal muscle, and in the connective tissue near the cricoarytenoid joint. The present findings suggest that NO participates in the autonomic, sensory, and motor innervation of the larynx.

Animals↗

PubMed1996

[BCG vaccination to Mycobacterium leprae infection in mice].

BCG vaccine (Tokyo strain) was given in BALB/cA mice intradermally 1 or 3 months before Mycobacterium leprae (M. leprae) challenge as modified Shepard's method. The vaccine dosage was 10(7-8) or 10(6). The BCG gave good protection in both dosages and both challenges against M. leprae infection. Lymphocytes proliferations of BCG-vaccinated splenocyte cultures in response to M. leprae lysate or BCG components (hsp65, 38 kD, 30 kD or 12 kD protein) were tested, and potent proliferative responses were seen in the cultures with M. leprae lysate and hsp65. Furthermore, gamma-IFN productions were positive in the cultures with M. leprae lysate or hsp65, but negative with other antigens. The production of gamma-IFN with hsp65 was never inhibited with polymyxin B, but inhibited with IL-10. These results show that BCG (Tokyo strain) is a useful vaccine for M. leprae infection in mice, and one of the components of BCG, hsp65, may be a effective antigen component for protection of M. leprae infection inducing Th1 type cytokine.

Animals↗

PubMed1996

[Interaction between nutrition and production of IL-1 beta, TNF alpha, and IL-6 by peripheral blood monocytes in patients with lung cancer].

Altered nutrient intake and metabolism are responsible for the progressive loss of body weight observed in most patients with advanced cancer, but the precise mechanism is still controversial. Under stressful conditions, some inflammatory cytokines such as IL-1 beta, TNF alpha, and IL-6 have a hypermetabolic effect and cause proteolysis and lipolysis in muscle and in fat tissues. To elucidate the mechanism of malnutrition in patients with lung cancer and normal food intake, we focused on the relationship between abnormal metabolism and these inflammatory cytokines. Patients with lung cancer were confirmed to be malnourished, and this malnutrition was found to be caused by hypermetabolism as estimated with visceral proteins, plasma levels of amino acids, and anthropometric indices. The production of IL-1 beta, TNF alpha, and IL-6 by blood monocytes was significantly higher in these patients than in healthy controls, and it correlated significantly and inversely with indices of nutrition. The present results suggest that nutritional status and these cytokines are closely related in patients with lung cancer. IL-1 beta, TNF-alpha, and IL-6 may serve as anti-cancer bioactive molecules, but "overfunctioning" of these cytokines may induce a hypermetabolic status that causes malnutrition, i.e. cancer cachexia.

Adult↗