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Biomedical subjects

K Omori

Publications and source records attributed to K Omori.

At least 19 recordsLinked to original sources
PubMed2002

Potential role of phosphodiesterase 7 in human T cell function: comparative effects of two phosphodiesterase inhibitors.

Even though the existence of phosphodiesterase (PDE) 7 in T cells has been proved, the lack of a selective PDE7 inhibitor has confounded an accurate assessment of PDE7 function in such cells. In order to elucidate the role of PDE7 in human T cell function, the effects of two PDE inhibitors on PDE7A activity, cytokine synthesis, proliferation and CD25 expression of human peripheral blood mononuclear cells (PBMC) were determined. Recombinant human PDE7A was obtained and subjected to cyclic AMP-hydrolysis assay. PBMC of Dermatophagoides farinae mite extract (Df)-sensitive donors were stimulated with the relevant antigen or an anti-CD3 monoclonal antibody (MoAb). PBMC produced IL-5 and proliferated in response to stimulation with Df, while stimulation with anti-CD3 MoAb induced CD25 expression and messenger RNA (mRNA) synthesis of IL-2, IL-4 and IL-5 in peripheral T cells. A PDE inhibitor, T-2585, which suppressed PDE4 isoenzyme with high potency (IC50 = 0.00013 microM) and PDE7A with low potency (IC50 = 1.7 microM) inhibited cytokine synthesis, proliferation and CD25 expression in the dose range at which the drug suppressed PDE7A activity. A potent selective inhibitor of PDE4 (IC50 = 0.00031 microM), RP 73401, which did not effectively suppress PDE7A (IC50 > 10 microM), inhibited the Df- and anti-CD3 MoAb-stimulated responses only weakly, even at 10 microM. PDE7 may play a critical role in the regulation of human T cell function, and thereby selective PDE7 inhibitors have the potential to be used to treat immunological and inflammatory disorders.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Substitution of Dmo1 with normal alleles results in decreased manifestation of diabetes in OLETF rats.

AIM: Dmo1 (Diabetes Mellitus OLETF type I) is a major quantitative trait locus for dyslipidaemia, obesity and diabetes phenotypes in the Otsuka Long Evans Tokushima Fatty (OLETF) rat strain. To evaluate possible metabolic and pathological improvements generated by correction of the Dmo1 genetic pathway, we produced congenic lines, in which both OLETF Dmo1 alleles are replaced by the F344-derived genome. METHODS: Congenic animals were produced by introgressing F344-derived Dmo1 alleles into the OLETF rat. Congenic animals of the fourth generation (BC4) were intercrossed to obtain F1 animals (BC4:F1). Animals of the next generation, BC4:F2, were used for this study. We used 23 BC4:F2 males harbouring homozygous replacement of the OLETF Dmo1 region with the F344-derived genome. Seven animals with OLETF-derived Dmo1 alleles were used as controls. RESULTS: Dmo1-F344/F344 congenic rats showed significant decreases in body weight, abdominal fat weight, serum triacylglycerols, total cholesterol, food consumption and blood glucose after glucose loading (13%, 39%, 45%, 27%, 18% and 27% respectively; p < 0.05) compared with Dmo1-OLETF/OLETF animals. Furthermore, histopathological analysis of the kidney showed that mesangial sclerosis, hyalin deposits and deposition of PAS-positive substance were significantly lower in Dmo1-F344/F344 animals (p < 0.05). CONCLUSION: Improvements in metabolic parameters and histopathological scores show that correction of the Dmo1 genetic pathway in the diabetic and mildly obese OLETF rat strain produces wide-ranging therapeutic effects. Thus, this pathway might represent a new drug target also applicable to humans.

Animals↗
PubMed2001

Utilization of ATP-binding cassette exporter for hyperproduction of an exoprotein: construction of lipase-hyperproducing recombinant strains of Serratia marcescens.

The Serratia marcescens extracellular lipase (LipA) is an enzyme applicable to enantioselective hydrolysis of racemic substrates. The enzyme is secreted through an ATP-binding cassette (ABC) exporter, the Lip system, encoded by the lipBCD genes. The S. marcescens recombinant carrying pLIPE121, which encodes the lipA gene in pUC19, exhibited a higher LipA production level than the wild-type strain. However, the level was lower than expected, and secretion was suggested to be a bottleneck. lipBCD plasmids were introduced into S. marcescens recombinants harboring lipA plasmids and the effectiveness of the lipBCD plasmids in elevating LipA productivity was investigated. S. marcescens strains harboring both lipA and lipBCD plasmids showed sevenfold greater extracellular LipA activity than the strain harboring the lipA plasmid alone. A high level of extracellular LipA production (1,300 kU/ml) and high plasmid stability (enough to carry out large-scale cultivation) were observed under non-selective conditions. Addition of L-proline and Tween 80 was effective in increasing cell growth of the recombinant, which led to high LipA production. In batch cultivation using a 30-l jar fermentor, LipA production was achieved at a high level of 5,200 kU/ml. This is the first report describing utilization of ABC exporter for the overproduction of an industrially important extracellular protein.

ATP-Binding Cassette Transporters↗
PubMed2001

Molecular cloning and characterization of the Cl(-) pump-associated 55-kDa protein in rat brain.

The Cl(-)-ATPase/pump in the plasma membrane of the rat brain is a candidate for active outwardly directed Cl(-) translocating systems. We recently isolated a Cl(-) pump, 520- or 580-kDa protein complex, which consisted of 51-, 55-, 60-, and 62-kDa proteins. In this study, we cloned a cDNA encoding a 55-kDa glycoprotein, designated as ClP55, which contained an open reading frame of 1512 base pairs encoding a protein of 504 amino acids including a signal peptide of 28 amino acids. Northern and Western blot analyses demonstrated expression of ClP55 mainly in the cerebrum. Application of antisense phosphorothioate oligonucleotides to cultured neurons resulted in a marked increase in the intracellular Cl(-) concentration ([Cl(-)](i)). Immunohistochemical analysis indicated that ClP55 was localized to the plasma membranes of neurons such as hippocampal pyramidal neurons and cerebellar Purkinje cells. Taken together, these results suggest that ClP55 is one of the Cl(-) pump subunits responsible for Cl(-) pump activity.

Adenosine Triphosphatases↗
PubMed2001

Novel, potent, and selective phosphodiesterase 5 inhibitors: synthesis and biological activities of a series of 4-aryl-1-isoquinolinone derivatives.

A novel class of potent and selective phosphodiesterase 5 (PDE5) inhibitors, 4-aryl-1-isoquinolinone derivatives, which have been designed by the comparison of the structure of cGMP and a previously reported 1-arylnaphthalene lignan, was disclosed. Among these compounds, methyl 2-(4-aminophenyl)-1,2-dihydro-1-oxo-7-(2-pyridinylmethoxy)-4-(3,4,5-trimethoxyphenyl)-3-isoquinoline carboxylate dihydrochloride (36a) exhibited potent PDE5 inhibitory activity (IC(50) = 1.0 nM) with high isozyme selectivities (IC(50) ratio: PDE1/PDE5 = 1300, PDE2/PDE5 > 10 000, PDE3/PDE5 > 10 000, PDE4/PDE5 = 4700, PDE6/PDE5 = 28). Compound 36a also showed the most potent relaxant effect on isolated rabbit corpus cavernosum (EC(30) = 7.9 nM). Compound 63 (T-1032), the sulfate form of 36a, was selected for further biological and pharmacological evaluation of erectile dysfunction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2001

Serratia ATP-binding cassette protein exporter, Lip, recognizes a protein region upstream of the C terminus for specific secretion.

Serratia marcescens ATP-binding cassette (ABC) exporter, the Lip system, secretes lipase (LipA(SM)), metalloproteases, and a cell surface layer protein homologue but not a heme acquisition protein, HasA (HasA(SM)). Secretion of HasA(SM) is limited to the Has(SM) system. However, HasA proteins from Pseudomonas fluorescens (HasA(PF)) and Pseudomonas aeruginosa were exported through the Lip and Has(SM) systems. To investigate the specificity in Lip exporter-mediated secretion, secretion analysis was performed using chimeras containing the HasA(PF) and HasA(SM) sequences. The segment Val-Ala-Leu (designated R1 to R3 sites), which is present close to the C terminus of HasA(PF) but not HasA(SM), was revealed to be involved in the substrate specificity of the Lip exporter. Introduction of amino acid substitutions into the R1-R5 region demonstrated that R1, R3, R4, and R5 sites require some specific amino acid residues for Lip-mediated secretion. The amino acid sequence of the region was conserved considerably among the proteins secreted by the Lip exporter. On the contrary, the region was not related to HasA secretion through the Has(SM) system. Interestingly, a typical C-terminal motif, so far regarded as a secretion signal, was not necessary for secretion through either the Lip or the Has(SM) exporter. In LipA(SM) secretion via the Lip system, the typical C-terminal motif was not essential either, but the presence of a sequence similar to Val-Ala-Leu and its location from the C terminus greatly affect the secretion level. Secretion analyses using hybrid exporters and competitors exhibited that the R1-R5 region was recognized by an ABC protein of the Lip exporter, LipB, and that the mutations aborting Lip-mediated secretion in the region resulted in a loss of the affinity to LipB. Thus, a determinant within the secretory protein for Lip-mediated secretion was fully defined.

Amino Acid Sequence↗
PubMed2001

Developmental changes in Cl(-)-ATPase activity in rat brains.

Developmental changes in brain Cl(-)-ATPase activity were examined using fetal, neonatal and adult rats. The Cl(-)-ATPase activity rapidly increased over 20 postnatal days to a level four-fold higher than that in an 18-day-old fetus. On Western blot analysis using an anti-Cl(-)-ATPase/pump 51 kDa subunit (ClP51) antibody, the amount of ClP51 protein increased in parallel with Cl(-)-ATPase activity. Immunohistochemistry using the same antibody showed Cl(-)-ATPase-like immunoreactivity on the cell membranes of neurons such as cerebral and hippocampal pyramidal cells and cerebellar Purkinje cells, where the immunoreactivity increased with developmental changes in the size and shape of the neurons. These findings suggest that neuronal Cl(-)-ATPase activity markedly increases during early postnatal development with an increase in the amount of Cl(-)-ATPase protein, which may support the formation of inwardly directed neuronal Cl(-) gradients.

Adenosine Triphosphatases↗
PubMed2001

Expression of TMEFF1 mRNA in the mouse central nervous system: precise examination and comparative studies of TMEFF1 and TMEFF2.

TMEFF1 and TMEFF2 are putative transmembrane proteins comprised of one epidermal growth factor (EGF)-like domain and two follistatin-like domains. Both TMEFF1 and TMEFF2 are predominantly expressed in the brain. We previously demonstrated that recombinant TMEFF2 protein can promote survival of neurons in primary culture and determined expression sites of TMEFF2 mRNA in the mouse central nervous system. To extend our understanding of TMEFF protein functions, we compared precise sites of expression of TMEFF1 and TMEFF2 mRNA using in situ hybridization analysis. Although both TMEFF genes are widely expressed in the brain, they exhibit different patterns of expression. TMEFF1 showed comparatively higher signals in the pyramidal cells of fifth layer of the cerebral neocortex, CA3, CA1 and subiculum regions of the hippocampus, locus coeruleus, and dentate cerebellar nucleus. In contrast, TMEFF2 is highly expressed in the medial habenular, CA2, CA3 and dentate gyrus region of the hippocampus, corpus callosum, cerebellar cortex and cranial nerve nuclei (III, IV, VII, X, XII). The results presented here indicate that expression of TMEFF1 and TMEFF2 are regulated differently and that they play region-specific roles in the central nervous system.

Animals↗
PubMed2001

Human Ca2+/calmodulin-dependent phosphodiesterase PDE1A: novel splice variants, their specific expression, genomic organization, and chromosomal localization.

We report here the identification of novel human PDE1A splice variants, their tissue distribution patterns, genomic structure, and chromosomal localization of the gene. We identified one N-terminus (N3) and one C-terminus (C3) by cDNA library screening and dbEST database search. These N- and C-termini, including the reported N-termini (N1 and N2) and C-termini (C1 and C2), combined to generate nine different PDE1A cDNAs. N1 and N2 are similar to the 5' ends of the bovine PDE1A proteins of 61 kDa and 59 kDa, respectively, and C1 and C2 are the 3' ends of the reported human PDE1A variants. The results of PCR and Southern blot analysis show that nine PDE1A splice variants exhibit distinctive tissue distribution patterns by the difference of the N-terminus. PDE1As with N2 were widely expressed in various tissues, mainly in the kidney, liver, and pancreas. On the other hand, PDE1As with N1 and N3 were particularly expressed at a high level in the brain and testis, respectively. These findings suggest that the distinct expression patterns among PDE1A variants depend on the several promoters situated upstream of exons encoding 5' ends of the variants. The PDE1A gene spans over 120 kb of genomic DNA, and consists of at least 17 exons and 16 introns. The PDE1A gene was located on human chromosome 2q32 by fluorescent in situ hybridization analysis.

Amino Acid Sequence↗
PubMed2001

Inhibition of cardiac delayed rectifier K+ currents by an antisense oligodeoxynucleotide against IsK (minK) and over-expression of IsK mutant D77N in neonatal mouse hearts.

The IsK (minK or KCNE1) protein is known to co-assemble with the KvLQT1 (KCNQ1) protein to form a channel underlying the slowly activating delayed rectifier K+ current (IKs). Controversy remains as to whether the IsK protein assembles with ERG (the ether-a-go-go-related gene) products to form or modulate the channel-underlying the rapidly activating delayed rectifier K+ current (IKr). We investigated the effects of antisense oligodeoxynucleotides (AS-ODN) against IsK and its mutant D77N [which underlies a form of long QT syndrome (LQT5) in humans] on the delayed rectifier K+ current (IK) of neonatal mouse ventricular myocytes in primary culture. Patch-clamp experiments on these cells showed that IK consists of IKs and IKr. IK was not recorded from ventricular cells transfected with AS-ODN, while it was recorded from cells transfected with the corresponding sense oligodeoxynucleotides (S-ODN). IK was not recorded from cells transfected with the D77N mutant, and the action potential duration was much longer than in cells transfected with wild-type IsK. Furthermore, HERG could not induce currents in COS-1 cells co-expressed with the D77N mutant and HERG (the human form of ERG). These results indicate that the IsK protein associates with both KvLQT1 and ERG products to modulate IKr and IKs in cardiac myocytes.

Action Potentials↗
PubMed2001

Genetic polymorphisms in the promoter and 5' UTR region of the Fc alpha receptor (CD89) are not associated with a risk of IgA nephropathy.

The molecular mechanisms of immunoglobulin A glomerulonephritis (IgAN), the most prevalent form of primary glomerulonephritis, remain poorly understood. Recently, the essential role of soluble Fc alpha receptor (FcalphaR) in the formation of the pathogenic immune complex has been revealed. We screened genomic DNA samples from patients with IgAN and those with other glomerular diseases for polymorphisms in the promoter and the 5'-untranslated region region of the FcalphaR gene by direct nucleotide sequencing. We found three common polymorphisms in this region, T-114C, T-27C, and T+56C from the putative transcription initiation site. Each genotype was determined in 151 patients with IgAN and 163 patients with other glomerular diseases shown to have no mesangial IgA deposition by renal biopsy. The haplotype analysis revealed tight linkage disequilibrium among them. An association study for the genotype, allele, and haplotype frequencies of the polymorphisms between the patients with histologically proven IgAN and those with other glomerular diseases showed no significant difference in the genotype, allele, and haplotype distributions between the two groups. The present study indicates that the analyzed polymorphisms of the FcalphaR gene do not appear to be primarily involved in the susceptibility to IgAN.

5' Untranslated Regions↗
PubMed2001

Geomagnetic disturbance associated with decrease in heart rate variability in a subarctic area.

BACKGROUND: Physical environmental variables, such as the natural variation in the geomagnetic field in and around the earth, influence biological processes and human health. The effect of geomagnetic disturbances on heart rate variability (HRV) in healthy students in a subarctic area is studied herein. SUBJECTS AND METHODS: Seven-day records by Holter ECG were obtained from eight clinically healthy subjects in Alta, Norway (70 N). Frequency- and time-domain measures of HRV were compared between 24-hour spans of high geomagnetic disturbance versus quiet conditions. RESULTS: A 5.9% increase in the 24-hour average of HR (P = 0.020) and a 25.2% decrease in HRV (P = 0.002) were documented on days of high geomagnetic disturbance. The decrease in spectral power was found primarily at frequencies lower than 0.04 Hz and was not statistically significant around 3.6 sec. CONCLUSIONS: The physiological mechanism involved may be other than the parasympathetic, usually identified with spectral power centered around 3.6 sec, a spectral region wherein no statistically significant differences were found.

Adult↗
PubMed2001

An evaluation of elastomeric impression materials based on surface compressive strength.

The setting times of seven commercially available elastomeric impression materials were determined using Wilson's reciprocating rheometer at temperatures 23 +/- 0.5 or 32 +/- 0.5 degrees C. The surface compressive strength and depression of these materials after setting time were measured using a rheometer (Fudoh). Each material was mixed according to the mixing proportion (base/accelerator or catalyst ratio) recommended by the manufacturer. The surface compressive strength and the depression of each material were measured by using a method which pressed the material to the edge of a sensitive rod (2.0 mm in diameter) connected to a load cell. In the case of silicone impression materials (additional type) at a temperature of 23 +/- 0.5 degrees C, the surface compressive strength and the depression of these materials were extremely stable after the setting time. However, the surface compressive strength of other materials except additional type materials increased markedly after setting time and the depression corresponding to the surface compressive strength decreased. These increased largely with the increase, in pressing speed to the sensitive rod. At 450 s from the setting time of all materials, there was an adequate correlation (r = 0.84) between measured values and theoretical values derived using the theory of elasticity.

Compressive Strength↗
PubMed2001

Genomic organization of the human phosphodiesterase PDE11A gene. Evolutionary relatedness with other PDEs containing GAF domains.

PDE11A is a dual-substrate, cAMP and cGMP, cyclic nucleotide phosphodiesterase (PDE). Presently four unique variants carrying distinct GAF sequences in the N-terminal region have been identified. While human PDE11A3 and PDE11A4 are known to be specifically expressed in testis and prostate, respectively, PDE11A1 was mainly detected in skeletal muscle. The human PDE11A gene was investigated and revealed to span > 300 kb, contain 23 exons and be mapped on chromosome 2q31. The transcription start sites of PDE11A1, PDE11A3 and PDE11A4 were determined, and the promoter sequences were revealed. Although 5' flanking genomic regions of PDE11A1 and PDE11A3 had a consensus TATA motif, that of PDE11A4 was a TATA-less but contained CCAAT box and Sp1-binding sequence. Interestingly, we found that the exon 2 sequence for N-terminal region of PDE11A3 encoded an N-terminal sequence of the cytochrome c pseudogene in an alternate reading frame, and that C-terminal region of the cytochrome c pseudogene in intron 2 was disrupted by the insertion of Alu repetitive sequence. Furthermore, we examined the exon-intron organization of the PDE2A gene and compared the exon organization among GAF-PDE family. The exon organization of the PDE11A catalytic domain was very similar to those of PDE5A and PDE6B. However, other GAF-PDEs, PDE2A and PDE10A, displayed different exon organization from PDE11A although these three PDEs are similar in their amino-acid sequences to each other. The findings suggested that PDE11A has a common ancestral gene with PDE5A and PDE6s, whereas PDE2A and PDE10A are generated separately from these three GAF-PDEs.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2001

Identification of rat cyclic nucleotide phosphodiesterase 11A (PDE11A): comparison of rat and human PDE11A splicing variants.

We have isolated and characterized rat cyclic nucleotide phosphodiesterase (PDE)11A, which exhibits properties of a dual-substrate PDE, and its splice variants (RNPDE11A2, RNPDE11A3, and RNPDE11A4). The deduced amino-acid sequence of the longest form of rat PDE11A splice variant, RNPDE11A4, was 94% identical with that of the human variant (HSPDE11A4). Rat PDE11A splice variants were expressed in a tissue-specific manner. RNPDE11A4 showed unique tissue distribution distinct from HSPDE11A4, which is specifically expressed in the prostate. Rat PDE11A splice variants were expressed in COS-7 cells, and their enzymatic characteristics were compared. Although the Km values for cAMP and cGMP were similar for all of them (1.3-1.6 and 2.1-3.9 microM, respectively), the Vmax values differed significantly (RNPDE11A4 >> RNPDE11A2 > RNPDE11A3). Human PDE11A variants also displayed very similar Km values and significantly different Vmax values (HSPDE11A4 >> HSPDE11A2 > HSPDE11A3 >> HSPDE11A1). The Vmax values of HSPDE11A4 for cAMP and cGMP were at least 100 times higher than those of HSPDE11A1. These observations indicate unique characteristics of PDE11A splicing variants.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2001

Antidesmoglein autoantibodies in silicosis patients with no bullous diseases.

BACKGROUND: Pemphigus is an autoimmune bullous disease characterized by the presence of antidesmoglein autoantibodies. However, the mechanism of its autoantibody production remains unknown. In previous reports, we have described rare cases of pemphigus and pemphigoid associated with silicosis. It is well known that during long-term silicosis, some autoimmune diseases, such as systemic sclerosis, systemic lupus erythematosus or rheumatoid arthritis, can occur. OBJECTIVE: The aim of this study was to explore the presence of pemphigus or pemphigoid autoantibodies in silicosis patients without clinical bullous diseases or collagen diseases. METHOD: The presence of pemphigus antibodies was examined in 54 silicosis patients with no associated bullous diseases, using immunofluorescence, the enzyme-linked immunosorbent assay (ELISA) for desmoglein 1 and 3, and immunoblotting methods. In the antibody-positive cases, HLA genotyping of peripheral lymphocytes was performed with PCR-RFLP. RESULTS: Seven out of the 54 patients were found to be positive for pemphigus antibodies and 1 for bullous pemphigoid by immunofluorescence. In addition, by ELISA, 6 patients were found to be positive against the desmoglein 1 antigen, 2 against the desmoglein 3 antigen and 2 against both desmoglein 1 and desmoglein 3. CONCLUSION: The results of the present study strongly suggest the occurrence of pemphigus and pemphigoid autoantibodies in patients with silicosis. It remains unclear whether such patients will develop an autoimmune bullous disease in the future. Accordingly, long-term follow-up of antibody-positive patients is required.

Aged↗
PubMed2001

[Special categories of elderly patients with intractable neurological diseases (NANBYO) in Toyama, Japan].

The purpose of this study was to elucidate special categories of elderly patients with intractable neurological diseases (NANBYO) in Toyama, Japan. This goal was accomplished through comparisons of data gathered in 1991 and 1997. Forty-eight (20 males, 28 females) with such diseases were recruited for the study and agreed to be interviewed. The surveys were performed by three public health center nurses. The same questionnaire was used in both years. The surveys show that the number of jobless patients and those who needed total support increased by approximately 20% from 1991 to 1997. In addition, it appears that the ratio of hospitalized patients and those who needed medical equipment installed at home increased considerably. The number of patients with caregivers increased by approximately 30%. As the caregivers got older, it was observed that the patients became more anxious about their health condition. Also, in both years, both patients and caregivers showed the highest concern about a sudden change in the patients' conditions. In conclusion, an assessment of patient and family needs is important for the development of a community health care system. It is also essential for all the parties in the field of health, medicine, and welfare, as well as volunteer groups, to have a good understanding of each other's services and to have a cooperative relationship coordinated by health centers through discussion of each individual case.

Adult↗