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Biomedical subjects

Y Morikawa

Publications and source records attributed to Y Morikawa.

At least 55 records · Page 3Linked to original sources
PubMed2000

Regulation of xyn3 gene expression in Trichoderma reesei PC-3-7.

The characteristics of regulation of the gene encoding the third xylanase (Xyn III) of a filamentous fungus, Trichoderma reesei PC-3-7, were studied by Northern blot analysis. A partial DNA sequence (185 bp) of the xyn3 gene was obtained by PCR amplification of genomic DNA of T. reesei PC-3-7 and sequenced. This xyn3 gene fragment was used as a probe for Southern and Northern blot analysis. The expression of the xyn3 gene was regulated at the transcriptional level. The xyn3 mRNA was expressed in mycelia of T. reesei PC-3-7 induced by Avicel, L-sorbose and sophorose, but not by xylose, xylooligosaccharides and birchwood xylan. Furthermore, it was observed that xyn3 was synchronously expressed with egll but not with xyn1 and xyn2 by L-sorbose, indicating that the xyn3 gene may be coordinately expressed with cellulase genes. By Southern blot analysis, the xyn3 gene was confirmed to exist as a single copy in both strains of T. reesei PC-3-7 and QM9414. However, no xyn3 mRNA appeared in the mycelia induced by any kind of inducers in T. reesei QM9414 even when total RNA was used in large excess, suggesting that the xyn3 gene in T. reesei QM9414 is in the dormant state and cannot be expressed. Therefore, T. reesei PC-3-7 may be a very useful strain for elucidating the induction mechanism of xylanase biosynthesis by cellulosic and xylanosic substrates, and also the regulatory correlation between cellulase and xylanase induction.

Amino Acid Sequence↗
PubMed2000

Hyperpolarization is not responsible for the acetylcholine-induced negative chronotropic action in the presence of isoproterenol.

It has been reported that acetylcholine hyperpolarizes the maximum diastolic potential of canine Purkinje fibers through a pathway involving a G protein and induces a decrease in their automaticity. It is unclear, however, whether the negative chronotropic action of acetylcholine in the presence of beta-adrenergic stimulation is due to the hyperpolarization of the maximum diastolic potential or a decrease in the slope of phase 4 depolarization. We used standard microelectrode techniques to study the negative chronotropic mechanism of acetylcholine in the presence of isoproterenol in adult canine Purkinje fibers. Fibers were incubated for 24 hours in Tyrode's solution alone (n = 10) or plus pertussis toxin (n = 10), and then superfused with acetylcholine (10(-9) to 10(-4) M) in the presence of isoproterenol (10(-7) M). Acetylcholine in the presence of isoproterenol significantly decreased automaticity without hyperpolarization of the maximum diastolic potential, and decreased the slope of phase 4 depolarization. The effects of acetylcholine on automaticity and the slope of phase 4 depolarization were attenuated by pertussis toxin. The present findings indicate that the negative chronotropic action of acetylcholine in the presence of isoproterenol is due to the decrease in the slope of phase 4 depolarization through a pathway involving a pertussis toxin-sensitive G protein and that it is not the result of hyperpolarization of the maximum diastolic potential.

Acetylcholine↗
PubMed2000

Expression of interleukin-6 receptor, leukemia inhibitory factor receptor and glycoprotein 130 in the murine cerebellum and neuropathological effect of leukemia inhibitory factor on cerebellar Purkinje cells.

Expression of glycoprotein 130 and the related receptors, including interleukin-6 receptor and leukemia inhibitory factor receptor, was examined in the murine cerebellum at the protein level. Western blot analysis revealed that interleukin-6 receptor, leukemia inhibitory factor receptor and glycoprotein 130 were expressed in the murine cerebellum. Immunoreactivities for interleukin-6 receptor, leukemia inhibitory factor receptor and glycoprotein 130 were strongly localized on the cell body of Purkinje cells, indicating that both interleukin-6 and leukemia inhibitory factor could act directly on Purkinje cells in murine adult mice. The expressions of interleukin-6 receptor, leukemia inhibitory factor receptor and glycoprotein 130 were observed on the cell membranes of Purkinje cells by immunoelectron microscopy. Immunoreactivity for the interleukin-6 receptor was also detected in the cytoplasm of Purkinje cells. Injection of a murine hemopoietic cell line, FDC-P1 cells, transfected with the complementary DNA encoding the leukemia inhibitory factor led to a reduction in calbindin-positive dendrites of the Purkinje cells.The present results suggest that the leukemia inhibitory factor affects cerebellar functions through Purkinje cells.

Animals↗
PubMed2000

Coronary risks after high-dose gamma-globulin in children with Kawasaki disease.

OBJECTIVES: The goals of the present study were to develop a predictive coronary risk scoring system after intravenous gamma-globulin (IVGG) therapy of any dose for the different preparations currently used in the treatment of children with Kawasaki disease and to determine the predictive value of the system. The previously reported scoring systems were based on treatment with high-dose IVGG therapy at limited doses and were determined using investigative methods. METHODS: Four hundred and fifty-one patients were randomized into one of three groups and received either i.v. polyethylene glycol-treated human immunoglobulin at a dose of either 200 (n = 147) or 400 mg/kg per day (n = 152) or freeze-dried sulfonated human immunoglobulin at 200 mg/kg per day (n = 152) for 5 consecutive days. We documented 31 cases of coronary abnormalities (CA). Univariate and multivariate logistic regression was performed using 49 clinical variables and the resulting predictive model was validated. RESULTS: The duration of fever (odds (I day)/odds (- 5 days)= 0.158; 95% confidence interval (CI) 0.0385-0.648), hemoglobin (odds (Q1 = 10.3)/odds (Q3 = 11.6) = 3.97; 95% CI 1.92-8.20), IgG (odds (Q1 = 1,900)/odds (Q3=2,658)=2.72, 95% CI 1.18-6.25) and IgA (odds (Q1 =72)/odds (Q3= 160) = 0.415; 95% CI 0.253-0.680) levels after completion of gamma-globulin infusion were independent predictors. The model is quasi-cross validated and has acceptable sensitivity and selectivity. The estimated risk and observed occurrence of CA coincide. CONCLUSIONS: Determinants of the risk of CA after IVGG therapy are a longer duration of fever, a lower IgG level, a higher IgA level and a lower hemoglobin level after IVGG infusion. This model is applicable for IVGG doses from 1 to 2 g/kg and for at least two different gamma-globulin preparations.

Child↗
PubMed2000

Inflammatory pseudotumor of the bladder in neonates.

Inflammatory pseudotumors of the bladder are rare in children. We describe a 7-day-old male neonate with inflammatory pseudotumor of the bladder. He presented with a 3-day history of macroscopic hematuria. Ultrasonography, computed tomography and cystoscopy showed an intravesical mass arising from the right lateral wall. Pathologic findings obtained by open excision revealed that the tumor had spindle-shaped cells without significant atypia infiltrating into submucosal fibrous tissue. There has been no evidence of recurrent tumor 12 months post-operatively. To our knowledge our case is the first presentation in a neonate among the reported pediatric cases.

Granuloma, Plasma Cell↗
PubMed2000

Roles of matrix, p2, and N-terminal myristoylation in human immunodeficiency virus type 1 Gag assembly.

Human immunodeficiency virus type 1 Gag protein is cotranslationally myristoylated at the N terminus and targeted to the plasma membrane, where virus particle assembly occurs. Particle assembly requires the ordered multimerization of Gag proteins, yet there is little direct evidence of intermediates of the reaction or of the domains that lead to each stage of the oligomerization process. In this study, following the expression in insect cells of C-terminally truncated Gag proteins and their purification, both the multimeric nature of each Gag protein and the ability to form Gag virus-like particles (VLP) were analyzed. Our results show that (i) the matrix (MA) domain forms a trimer and contributes to a similar level of oligomerization of the assembly-competent Gag; (ii) the p2 domain, located at the capsid/nucleocapsid junction, is essential for a higher order of multimerization (>1,000 kDa); (iii) the latter multimerization is accompanied by a change in Gag assembly morphology from tubes to spheres and results in VLP production; and (iv) N-terminal myristoylation is not required for either of the multimerization stages but plays a key role in conversion of these multimers to Gag VLP. We suggest that the Gag trimer and the > 1,000-kDa multimer are intermediates in the assembly reaction and form before Gag targeting to the plasma membrane. Our data identify a minimum of three stages for VLP development and suggest that each stage involves a separate domain, MA, p2, or N-terminal myristoylation, each of which contributes to HIV particle assembly.

Animals↗
PubMed2000

Trends in stroke incidence and acute case fatality in a Japanese rural area : the Oyabe study.

BACKGROUND AND PURPOSE: Stroke mortality in Japan has significantly declined during recent decades. To determine the cause of this decrease, we studied the trends in stroke incidence and case fatality within 28 days after stroke in a rural area in Japan. METHODS: We used a population-based registry during 1977-1991 in Oyabe, a rural area in the central part of Japan. The average population aged 25 years and older numbered 32 859 persons. Changes in age-standardized stroke incidence rate were calculated and compared between the 3 periods 1977-1981, 1982-1986, and 1987-1991. The 28-day case fatality rate was evaluated and also compared between the 3 periods by onset year. RESULTS: The total number of strokes was 2068. The age-standardized incidence rate of all strokes decreased during the 15-year period, from 605 to 417 per 100 000 in men and from 476 to 329 per 100 000 in women. A marked decline was found during 1977-1986 but was not apparent during 1987-1991. Moreover, there was an increase in the group aged 75 years and older. The 28-day case fatality rates for all strokes improved from 18.0% to 14.2% in men and from 26.8% to 19.1% in women during the observation period. CONCLUSIONS: These data indicate that declines in the stroke incidence and the 28- day case fatality have been associated with a marked decrease in stroke-related mortality in Japan.

Acute Disease↗
PubMed2000

Gene expression of receptors for IL-6, LIF, and CNTF in regenerating skeletal muscles.

The biological actions of interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) are mediated via respective functional receptor complexes consisting of a common signal-transducing component, gp130, and other specific receptor components, IL-6 receptor alpha (IL-6R), LIF receptor beta (LIFR), and CNTF receptor alpha (CNTFR). IL-6, LIF, and CNTF are implicated in skeletal muscle regeneration. However, the cell populations that express these receptor components in regenerating muscles are unknown. Using in situ hybridization histochemistry, we examined spatiotemporal expression patterns of gp130, IL-6R, LIFR, and CNTFR mRNAs in regenerating muscles after muscle contusion. At the early stages of regeneration (from 3 hr to Day 2 post contusion), significant signals for gp130 and LIFR mRNAs were detected in myonuclei and/or nuclei of muscle precursor cells (mpcs) and in mononuclear cells located in extracellular spaces between myofibers after muscle contusion, but IL-6R mRNA was expressed only in mononuclear cells. At Day 7 post contusion, signals for gp130, LIFR, and IL-6R mRNAs were not detected in newly formed myotubes, whereas the CNTFR mRNA level was upregulated in myotubes. These findings suggest that the upregulation of receptor subunits in distinct cell populations plays an important role in the effective regeneration of both myofibers and motor neurons. (J Histochem Cytochem 48:1203-1213, 2000)

Animals↗
PubMed2000

Pulmonary hypoplasia induced by liquid paraffin injection into fetal thoracic cavity with special reference to renal development in rats.

The present study was designed to clarify lung-kidney interrelation in fetal rats. On fetal day 20, liquid paraffin (LP) was injected into fetal thoracic cavity to produce pulmonary hypoplasia. No significant difference in body and renal weights were noted between the LP injected and control fetuses. The weight of lung, however, was significantly lower in the LP injected fetuses than in the control ones. Histological examinations on the lung and kidney of the LP injected fetuses revealed that the lung was hypoplastic characterized by rich interstitium and reduced air spaces. In the kidney, mature types of glomeruli and profiles of proximal tubules near them were increased in number. Furthermore, strong expression of EGF immunoreactivity was noted in the apical cytoplasm of epithelium of the proximal tubules in the LP injected fetuses. These findings indicate that lung-kidney interrelation exists in fetal rats during late gestational days, and suggest that interruption of the lung development induces accelerated growth of the kidney in fetal rats.

Animals↗
PubMed2000

Development of SCAR markers to the PVY resistance gene Ryadg based on a common feature of plant disease resistance genes.

Sequence-characterized amplified regions (SCARs) were developed, based on nucleotide differences within resistance gene-like fragments isolated from a potato plant carrying the Ryadg gene, which confers extreme resistance to potato Y potyvirus (PVY). It originates from Solanum tuberosum subsp. andigena, and a susceptible potato plant. SCARs were tested using 103 potato breeding lines and cultivars with diverse genetic backgrounds derived from Europe, North America, and Japan. Two markers showed high accuracy for detection of the Ryadg gene. The SCAR marker RYSC3 was generated only in genotypes carrying Ryadg. The SCAR marker RYSC4 was detected in all genotypes carrying Ryadg but also in four PVY-susceptible genotypes. Neither marker was detected in genotypes carrying other Ry genes originating from different species than S. tuberosum subsp. andigena. Therefore, these SCAR markers should be powerful tools in marker-assisted selection for Ryadg in potato breeding programs, and should also be useful for cloning of the Ryadg gene.

Breeding↗
PubMed2000

[Sarcoidosis associated with lupus pernio and acute pulmonary cavitation].

Lupus pernio, an uncommon skin condition due to sarcoidosis in Japan, is a chronically persistent, violaceous skin lesion primarily involving the nose, cheek, ears, and fingers. It has often been associated with chronic fibrotic non-resolving pulmonary sarcoidosis. We reported a case of sarcoidosis associated with lupus pernio and primary pulmonary cavitation as a rare manifestation in the lung. A 44-year-old man visited our hospital in January 1986 because of a 3-year history of swollen and violaceous cheeks (lupus pernio) and an 8-year history of erythema in both upper and lower limbs. The biopsy specimen obtained from the skin lesion revealed epithelioid cell granulomas without any evidence of Mycobacterium or fungal growth. Serum ACE (45.4 U/ml) was elevated. Chest X-ray films and computed tomographic (CT) scans showed bilateral hilar lymphadenopathy, nodules, multiple small opacities, and reticulo-linear opacities. Gallium scintigraphy demonstrated abnormal uptake in the mediastinal and hilar lymph nodes and lung fields. The patient had not received corticosteroids. Chest X-ray films and CT scans in July 1989 showed increased opacities and cavitation. Because pyogenic bacteria and acid-fast bacilli were not detected by repeated sputum examinations or bronchial washing, we concluded that the cavitary lesions were manifestations of primary pulmonary cavitation due to sarcoidosis. Prednisolone (40 mg daily) was prescribed and the dosage was gradually tapered. The lung lesions gradually resolved and have not recurred.

Adult↗
PubMed2000

Dust exposure and lung cancer mortality in tunnel workers.

The eastern part of the Toyama Prefecture in Japan is one of the high-incidence areas of silicosis due to tunnel construction. In 1977 and 1978, we conducted a questionnaire survey primarily concerning the occupational history of all male inhabitants over 30 years of age living in five villages in this area and found 603 tunnel workers and inhabitants without dust history. These workers have been followed up to 1994 for about 17 to 18 years to clarify the relationship between tunnel work and lung cancer mortality. The SMR's of workers with dust exposure for all causes and for lung cancer was 120 and 188, respectively, which was significantly higher than those of the Japanese general population. After adjustment for age and smoking habits using Cox's proportional hazard model, tunnel work showed a significant relationship to mortality. Mortality risk ratio of tunnel workers was 2.15 compared with that of inhabitants without dust exposure history.

Adult↗
PubMed1999

Molecular cloning of a cDNA encoding mouse A15, a member of the transmembrane 4 superfamily, and its preferential expression in brain neurons.

A15, a member of the transmembrane 4 superfamily (TM4SF), was isolated by differential screening of the cDNAs that are preferentially expressed on immature T cells. As a first step in the study of the biological function of the A15 molecule, we isolated cDNAs encoding the entire coding region of mouse A15. Nucleotide sequence analysis of the cDNAs revealed that mouse A15 shares 97% amino acid sequence identity with its human counterpart. The mouse A15 protein product has not yet been characterized, but is predicted to be 244 amino acids with four hydrophobic domains. Northern blot analysis of the RNA samples from various mouse tissues disclosed that the A15 transcripts are expressed most strongly in the brains, and are detectable in the colon, muscle, heart, kidney, and spleen. In situ hybridization of the mouse brain with ribo-probe established that the A15 transcripts are expressed primarily in neurons of the frontal cortex, olfactory bulb, dentate gyrus, caudoputamen, and CA3 region of the hypothalamus as well as in Purkinje cells in the cerebellar cortex, which strongly suggests that A15 may have a special function in the fundamental neuronal functioning of the higher nervous system.

Amino Acid Sequence↗
PubMed1999

In vitro assembly of human immunodeficiency virus type 1 Gag protein.

Retroviral Gag protein is sufficient to produce Gag virus-like particles when expressed in higher eukaryotic cells. Here we describe the in vitro assembly reaction of human immunodeficiency virus Gag protein, which consists of two sequential steps showing the optimal conditions for each reaction. Following expression and purification, Gag protein lacking only the C-terminal p6 domain was present as a monomer (50 kDa) by velocity sedimentation analysis. Initial assembly of the Gag protein to 60 S intermediates occurred by dialysis at 4 degrees C in low salt at neutral to alkaline pH. However, higher order of assembly required incubation at 37 degrees C and was facilitated by the addition of Mg(2+). Prolonged incubation under these conditions produced complete assembly (600 S), equivalent to Gag virus-like particles obtained from Gag-expressing cells. Neither form disassembled by treatment with nonionic detergent, suggesting that correct assembly might occur in vitro. Electron microscopic observation confirmed that the 600 S assembly products were spherical particles similar to authentic immature human immunodeficiency virus particles. The latter assembly stage but not the former was accelerated by the addition of RNA although not inhibited by RNaseA treatment. These results suggest that Gag protein alone assembles in vitro, but that additional RNA facilitates the assembly reaction.

Animals↗
PubMed1999

Fetal liver development requires a paracrine action of oncostatin M through the gp130 signal transducer.

Fetal liver, the major site of hematopoiesis during embryonic development, acquires additional various metabolic functions near birth. Although liver development has been characterized biologically as consisting of several distinct steps, the molecular events accompanying this process are just beginning to be characterized. In this study, we have established a novel culture system of fetal murine hepatocytes and investigated factors required for development of hepatocytes. We found that oncostatin M (OSM), an interleukin-6 family cytokine, in combination with glucocorticoid, induced maturation of hepatocytes as evidenced by morphological changes that closely resemble more differentiated hepatocytes, expression of hepatic differentiation markers and intracellular glycogen accumulation. Consistent with these in vitro observations, livers from mice deficient for gp130, an OSM receptor subunit, display defects in maturation of hepatocytes. Interestingly, OSM is expressed in CD45(+) hematopoietic cells in the developing liver, whereas the OSM receptor is expressed predominantly in hepatocytes. These results suggest a paracrine mechanism of hepatogenesis; blood cells, transiently expanding in the fetal liver, produce OSM to promote development of hepatocytes in vivo.

Animals↗
PubMed1999

Gene expression of histamine H1 receptor in guinea pig primary sensory neurons: a relationship between H1 receptor mRNA-expressing neurons and peptidergic neurons.

Pharmacological studies have suggested that a subgroup of primary sensory neurons is responsive to histamine via the histamine H1 receptor. We addressed this issue using in situ hybridization histochemistry with a cRNA probe for the guinea pig H1 receptor gene. About 15% of the trigeminal and lumber dorsal root ganglion (DRG) neurons, but none of nodose ganglion neurons, were intensely labeled with this probe. The H1 receptor mRNA-positive neurons were exclusively small in size, and were demonstrated to give rise to unmyelinated fibers by ultrastructural analysis of isolectin B4-labeling. However, the H1 receptor mRNA-expressing DRG neurons were not immunoreactive to substance P (SP) and calcitonin gene-related peptide (CGRP). A marked increase in the number of mRNA-positive DRG neurons were observed 1-5 days after a crush injury of the sciatic nerve (3-4-fold of the control value). These neurons turned mRNA-positive after the nerve crush were also mainly small-sized. The mRNA signals were detected in many peptidergic (SP/CGRP) neurons, in contrast to the normal state. On the other hand, in the neurons which showed intense labeling in the normal condition, the mRNA signals were down-regulated. These results suggest that primary sensory neurons include two kinds of H1 receptor-expressing sensory neurons, one expressing H1 receptor mRNAs in the normal state and the other up-regulating the mRNAs following the peripheral nerve damage.

Animals↗
PubMed1999

Leukemia inhibitory factor, glial cell line-derived neurotrophic factor, and their receptor expressions following muscle crush injury.

Using in situ hybridization histochemistry, we characterized the spatiotemporal gene expression patterns of leukemia inhibitory factor (LIF) and glial cell line-derived neurotrophic factor (GDNF), and their receptor components (LIFR, GFR-alpha1, RET) induced in muscle cells, intramuscular nerves, and motoneurons in the regeneration processes of both muscle cells and nerves following muscle contusion. Muscle contusion induced upregulation of GDNF and GFR-alpha1 mRNAs in Schwann cell-like cells in the intramuscular nerves and of LIFR mRNA in damaged muscle cells. LIFR, GFR-alpha1, and RET mRNA expressions in motoneurons were upregulated following muscle contusion. Muscle contusion also induced more rapid, prominent transactivations of GFR-alpha1 and RET genes in motoneurons than did sciatic nerve axotomy. These findings suggest that rapid and prominent upregulation of the receptor components for LIF and GDNF in motoneurons is important for the regeneration of intramuscular motor nerves damaged by muscle contusion.

Animals↗