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Biomedical subjects

K Omori

Publications and source records attributed to K Omori.

At least 109 records · Page 6Linked to original sources
PubMed1997

Expression of rat cGMP-binding cGMP-specific phosphodiesterase mRNA in Purkinje cell layers during postnatal neuronal development.

The cDNA encoding rat cGMP-binding, cGMP-specific phosphodiesterase (cGB-PDE) was isolated from a rat lung cDNA library. Although the deduced amino acid sequence showed 93.4% similarity with that of bovine cGB-PDE, the N-terminal portion of rat cGB-PDE was extremely different from that of bovine. Northern blot analysis indicated that cGB-PDE transcripts in rats were expressed not only in aorta and lung, but also in several other tissues including cerebellum. In situ hybridization analysis demonstrated that cerebellar expression of cGB-PDE was confined to Purkinje cell layers in adult rats. To clarify the role of cGB-PDE in the cerebellum, we investigated expression of cGB-PDE mRNA in rats of various ages. cGB-PDE mRNA was not observed in the cerebellum of newborn rats, but levels of a cGB-PDE mRNA were markedly increased between 4 days and 28 days of age and reached a maximum in eight-week-old rats. In this study, we suggest that cGB-PDE plays important roles not only in regulating the relaxation of vascular vessels, but also in establishing neuronal networks in the cerebellum at an early postnatal stage. In addition the NO/cGMP/cGB-PDE pathway appears to be essential for the induction of long-term depression.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1997

Inwardly rectifying potassium channels expressed by gene transfection into the green Monkey kidney cell line COS-1.

1. cDNA encoding a functional inwardly rectifying K+ (IRK1) channel was transfected into COS-1 cells (a Green Monkey kidney cell line) using the liposome method, and voltage clamp experiments were done after 48-72 h. 2. Transfected cells showed inward rectification under whole-cell recording. The unitary current-voltage relationships in the inside-out configuration were almost linear in the absence of internal Mg2+ and polyamines, and the channel conductance averaged 34.1 +/- 2.0 pS (n = 15) at 23-26 degrees C. 3. Internal Mg2+ (2-10 microM) induced sublevels in the outward current with one-third and two-thirds of the unitary amplitude as in native channels. 4. To determine the subunit stoichiometry, we constructed tandem multimeric cDNAs consisting of the coding sequences of the IRK1 gene linked in a head-to-tail fashion. Cells transfected with tandem homomultimers up to octamers showed similar inwardly rectifying K+ channels. 5. A mutation (E138Q) eliminated the ionic conductance of the channel. Channels expressed by dimeric constructs containing a single mutant have a conductance ranging between 5 and 35 pS. 6. The E138Q mutant cotransfected with a wild-type dimeric, trimeric or tetrameric construct did not alter the channel conductance. The results do not support the notion that IRK1 channel proteins consist of four subunits.

Animals↗
PubMed1997

Vascular endothelial growth factor expression in choroidal neovascularization in rats.

BACKGROUND: The pathogenesis of choroidal neovascularization is largely unknown. We investigated vascular endothelial growth factor (VEGF) expression in laser-induced choroidal neovascularization (CNV) in rats. METHODS: Intense krypton laser photocoagulation was applied to the posterior poles of the eyes of pigmented rats to induce CNV, which was confirmed by fluorescein angiography and histopathology. The eyeballs were enucleated 1, 3, 7, 14 and 28 days after laser photocoagulation. Cryostat sections were prepared for immunofluorescence staining using anti-VEGF and macrophage marker (ED1) antibodies. The posterior segments of eyeballs pooled from photocoagulated and control rats were submitted for immunoprecipitation and immunoblotting by the anti-VEGF antibody, and reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of VEGF mRNA. RESULTS: Very weak immunoreactivity for anti-VEGF antibody was found in the ganglion cell layer, inner nuclear layer, and retinal pigment epithelium (RPE) in the normal retina. In the development of CNV, strong positive staining for anti-VEGF antibody was found in photocoagulated areas in the subretinal space and choroid. Double immunofluorescence staining showed that many cells in lasered lesions were positive both for anti-VEGF and macrophage marker ED1 antibody staining in the early stage of this model. Immunoblots showed a positive band for the VEGF molecule in treated but not control animals. RT-PCR results demonstrated upregulation of VEGF transcripts in the CNV model compared with normal animals. CONCLUSIONS: Our findings showed the upregulation of VEGF expression in experimentally induced CNV, where it may be involved in promoting choroidal angiogenesis. Macrophages may be one of the main sources of VEGF in the early stage of the disease.

Animals↗
PubMed1997

Acoustic characteristics of rough voice: subharmonics.

This study investigates the relationship between rough voice and the presence of subharmonics, which correspond to smaller yet distinct peaks located between two consecutive harmonic peaks in the power spectrum. Spectrum analysis was undertaken in 389 pathologic voices, of which 20 had subharmonics. Although all 20 voices had roughness perceptually, 8 had normal jitter and/or shimmer. The degree of roughness had a significant inverse relationship with the frequency of subharmonics. By digital signal processing, sound samples with various types of subharmonics were synthesized and perceptually analyzed. Power and frequency of subharmonics in the synthesized sound also had significant relationships with the degree of roughness. Rough voice is acoustically characterized not only by jitter and shimmer but also by the presence of subharmonics in the power spectrum. Subharmonics are important acoustic properties for objective evaluation of rough voices.

Adult↗
PubMed1997

Use of hydroxyapatite for reconstruction after surgical removal of intraosseous hemangioma in the zygomatic bone.

Two rare cases of intraosseous hemangiomas in the zygomatic bone that were repaired after surgical removal of the tumor with hydroxyapatite implants are reported. Case 1 is a 42-year-old woman, and case 2 is a 46-year-old man. They complained of swelling in the right cheek. An intraosseous tumor in the right zygomatic bone was observed in both patients. The tumor was resected, and hydroxyapatite was employed to repair the defect caused by removal. After 4 years since the operation in case 1 and 8 months in case 2, the patients show satisfactory cosmetic appearance. Hydroxyapatite implant was useful for reconstruction of the defect after surgical removal of hemangiomas in the zygomatic bone.

Adult↗
PubMed1997

Lipase secretion by bacterial hybrid ATP-binding cassette exporters: molecular recognition of the LipBCD, PrtDEF, and HasDEF exporters.

Serratia marcescens secretes several proteins, such as the lipase LipA, the metalloprotease PrtA, and the heme-binding protein HasA, which is required for heme acquisition, through two N-terminal signal peptide-independent systems that are classified as bacterial ATP-binding cassette (ABC) exporters. One is the ABC exporter for HasA, consisting of the ABC protein HasD, the membrane fusion protein (MFP) HasE, and the outer membrane protein (OMP) HasF. The second, composed of LipB (an ABC protein), LipC (an MFP), and LipD (an OMP), promotes secretion of LipA and PrtA in Escherichia coli recombinant clones. PrtA, which shows homology to the Erwinia chrysanthemi metalloproteases, is efficiently secreted by E. coli cells carrying the E. chrysanthemi ABC exporter PrtD (ABC protein)-PrtE (MFP)-PrtF (OMP). The existence of distinct systems in this bacterium and of various substrates for these systems allowed the study of protein secretion by heterologous Has, Lip, and Prt systems and by Has-Lip and Lip-Prt hybrid exporters in the genuine host as well as in E. coli. For that purpose, lipB-, lipC-, and lipD-deficient mutants were isolated from S. marcescens 8000 and their secretion of LipA and PrtA was analyzed. This demonstrated that a unique exporter, the Lip apparatus, in S. marcescens secretes both LipA and PrtA. Hybrid exporters were tested for secretion of HasA and LipA. The LipB-HasE-HasF exporter allowed secretion of LipA but not HasA, showing that the ABC protein LipB is responsible for the substrate specificity. LipA, HasA, and E. chrysanthemi PrtC were secreted via heterologous exporters and via some hybrid exporters. Analysis of secretion via hybrid exporters showed that specific interactions occur between MFPs and OMPs in these systems. These genetic experiments demonstrated that specific interactions between the ABC protein and the MFP are required for the formation of active exporters.

ATP-Binding Cassette Transporters↗
PubMed1997

Vocal fold atrophy: quantitative glottic measurement and vocal function.

Videostroboscopic glottic measurements and vocal function were evaluated in 41 vocal fold atrophy patients with bowed vocal folds. The amount of bowing in the resting position and the glottal gap area and vibratory amplitude during phonation were measured from digitized videostroboscopic images. Vibratory amplitude was not decreased on atrophic vocal folds. With the same amount of total bowing, the glottal gap area for bilateral atrophy was smaller than for unilateral atrophy. These results suggest that vocal fold atrophy is not disadvantageous to thyroplasty type I, and that bilateral procedures may produce a better outcome than a unilateral procedure in the treatment of bilateral atrophy. Acoustic, aerodynamic, and perceptual parameters of vocal function were measured. The acoustic high-frequency power ratio and the H-index correlated with the glottal gap area. The mean flow rate correlated with the amount of bowing. The degree of dysphonia was related to the size of the glottal gap and bowing.

Adult↗
PubMed1997

[A case of primary fibrous histiocytoma of the lung].

Fibrous histiocytoma is non-epithelial malignant tumor mainly arising from soft tissue in extremities and body. Those derived from lung are rare. A 71-year-old female was admitted to our hospital because of an abnormal shadow on chest X-ray film. Preoperative diagnosis was not obtained by various examination. The tumor was located in right upper lobe (S2) and partial resection of right upper lobe was performed. Pathological diagnosis was fibrous histiocytoma of borderline malignancy. After the operation, adjuvant therapy was not done. The patient is doing well without recurrence and metastasis, during 4 years after the operation. However, careful follow-up should be necessary for long term.

Aged↗
PubMed1996

Structure of the 5'-flanking regulatory region of the mouse gene encoding the clearance receptor for atrial natriuretic peptide.

A full-length cDNA, encoding the mouse atrial natriuretic peptide clearance receptor (ANP-CR), was isolated from a mouse lung cDNA library. The deduced amino acid sequence of the mouse ANP-CR, showing a typical tripartite organization which lacks a guanylyl cyclase domain, was extremely well conserved compared with the ANP-CR homologs. To understand the molecular mechanisms underlying the regulation of mouse ANP-CR gene expression and to define the essential DNA sequences for the transcriptional activity, a genomic clone containing over 9 kb of the 5'-flanking region of the mouse ANP-CR gene has been isolated from a mouse genomic library. Sequence analysis revealed that the 2.3-kb region upstream from an ATG codon of the mouse ANP-CR gene contained a number of putative regulatory elements; TATA box, CAAT box, cAMP response element, AP-1 and two shear stress responsive elements. Additionally, an unusual feature was the presence of the tandem-repeated AP-2-like elements, which were closely overlapped with SP-1 element. Promoter analysis using deletion plasmids in mouse Balb/3T3 cells, highly producing ANP-CR mRNA, demonstrated that deletion of the sequence from -144 to +46 relative to the transcription start point caused a dramatic decrease of the transcriptional activity and that the TATA box at -269 was not essential for the basal transcriptional activity. Primer extension analysis indicated that transcription of the mouse ANP-CR gene starts from at least two major sites, suggesting that the sequence from -144 to +46, which was shown to involve a novel sequence composed of tandem-repeated TATA-box-like elements, contained promoter sequences. Furthermore, cis-acting negative elements were shown to be situated in three regions (from -1178 to -708, from -707 to -625 and from -248 to -145) of the mouse ANP-CR gene promoter.

Amino Acid Sequence↗
PubMed1996

Singing power ratio: quantitative evaluation of singing voice quality.

This paper presents a parameter for objectively evaluating singing voice quality. Power spectrum of vowel sound /a/ was analyzed by Fast Fourier Transform. The greatest harmonics peak between 2 and 4 kHz and the greatest harmonics peak between 0 and 2 kHz were identified. Power ratio of these peaks, termed singing power ratio (SPR), was calculated in 37 singers and 20 nonsingers. SPR of sung /a/ in singers was significantly greater than in nonsingers. In singers, SPR of sung /a/ was significantly greater than that of spoken /a/. By digital signal processing, power spectrum of sung /a/ was varied, and the processed sounds were perceptually analyzed. SPR had a significant relationship with perceptual scores of "ringing" quality. SPR provides an important quantitative measurement for evaluating singing voice quality for all voice types, including soprano.

Adult↗
PubMed1996

Quantitative criteria for predicting thyroplasty type I outcome.

The purpose of this study was to ascertain the relation between preoperative glottal gap and postoperative vocal function in thyroplasty type I. Twenty-two of 64 patients who underwent thyroplasty type I between 1987 and 1994 were studied. In preoperative digitized laryngostroboscopic images, the glottal-gap, width (GGW), shape, and area were examined at the maximum closure of vibration and normalized by membranous vocal-fold length (MVFL). Postoperative vocal function analysis was performed with aerodynamic and acoustic measurements and compared with preoperative videostroboscopic images. In patients with preoperative posterior GGW of less than 10% of MVFL, postoperative vocal function was significantly better than in other patients. Although thyroplasty type I is an excellent medialization technique, it may need to be combined with a posterior closure procedure in patients with large posterior gaps.

Adult↗
PubMed1996

Quantitative videostroboscopic measurement of glottal gap and vocal function: an analysis of thyroplasty type I.

The goal of surgical medialization of the vocal fold is to attain complete glottic closure. The purpose of this study is to quantify the glottal gap and to examine the relationship between glottal gap and vocal function perioperatively in thyroplasty type I. Glottal gap area was measured in 20 patients at the point of maximum closure of vocal fold vibration in digitized laryngeal stroboscopic images and was normalized by the square of vocal fold length. Glottal gap area thus measured was correlated with results obtained from well-accepted acoustic, aerodynamic, and perceptual measures of vocal function. The glottal gap was significantly reduced after thyroplasty type I. In patients with small preoperative glottal gaps, the amplitude of vocal fold vibration was significantly improved. This study verifies that quantitative videostroboscopic measurement of the glottal gap is a useful means of objective evaluation of glottic incompetence and of the results of thyroplasty type I.

Acoustics↗
PubMed1996

Omohyoid muscle transposition for the treatment of bowed vocal fold.

Imperfect glottal closure is usually the most important factor causing dysphonia in patients with bowing of the vocal folds. We have performed laryngeal framework surgery, which allows the medialization of the vocal folds from the outside without creating any scar tissue on them. Over the past 6 years, however, we encountered three cases with marked bowing of the vocal folds that could not be cured by laryngeal framework surgery alone. We used an open laryngeal procedure in these cases, even though such procedures had been considered contraindicated in the treatment of hoarseness. After performing a laryngofissure, we made a small pocket beneath the vocal fold mucosa at the anterior commissure. The superiorly based omohyoid muscle flap was then transposed into the mucosal pocket and sutured to the vocal process. This procedure should be considered an option in treating highly bowed vocal folds.

Adult↗
PubMed1996

[Na, K-ATPase--its structure, function and intracellular transport].

Na, K-ATPase is an integral plasma membrane protein and plays essential roles such as maintaining sodium and potassium ion gradients across the plasma membrane. The enzyme consists of the alpha and the beta subunits with the stoichiometry of one to one. Three alpha subunit and two beta subunit isoforms have been detected in animal cells with the tissue-specific expression of both subunits. Recent advances in molecular biological studies on the Na, K-ATPase enable us to understand the structure-function relationships and mechanisms of intracellular transport of the enzyme. In this article we review the findings deduced from these studies, especially on the assembly and transport to the plasma membrane of the alpha and beta subunits.

Animals↗
PubMed1995

Distribution of neurone-specific clathrin light chain b between clathrin-coated vesicle subclasses.

The clathrin light chains (LCs) may serve to introduce diversity into the structure and/or function of clathrin-coated vesicles (CVs). To understand such involvement of LCs, it is advantageous to study the distribution of various LC subclasses among CV populations with specified structure and/or function. We have previously separated three populations of CV from rat brain, the small- and medium-sized populations originated from neurones and large-sized one from glial cells. In the present study, we examined whether the neurone-specific LCb is localized in either or both of those neuronal CV populations by immunogold electron microscopy, and showed the distribution of the LCb between both CVs. These findings suggest that the neurone-specific LC subclass does not specify morphologically distinct subtype of neuronal CVs but plays a role in constructing the CVs generally smaller than those from other tissues and/or in neurone-specific mechanisms associated with both of the neuronal CVs.

Animals↗
PubMed1995

Divergence of a flagellin protein in Serratia marcescens.

A gene (hag) encoding the flagellin (Fla) protein was cloned from Serratia marcescens (Sm) 8000, the wild-type strain of Sr41. The hag gene codes for a 348-amino-acid (aa) protein of 36.7 kDa. The predicted aa sequence showed 79% homology compared with the Fla of Sm 274 which has been reported previously [Harshey et al., Gene 79 (1989) 1-8]. Dot-matrix analysis of the Sm 8000 Fla showed that the N- and C-terminal regions of this protein were highly similar to those of other bacterial Fla. However, the aa sequence of the middle portion was quite different from that of a variant strain of the same species, Sm 274.

Amino Acid Sequence↗