Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 325 records · Page 18Linked to original sources

PubMed2000

The relationship between chronic hypoxemia and activation of the tumor necrosis factor-alpha system in patients with chronic obstructive pulmonary disease.

Although circulating tumor necrosis factor (TNF)-alpha levels have been found to be increased in weight-losing patients with chronic obstructive pulmonary disease (COPD), the main causes for this phenomenon remain to be elucidated. Since hypoxia itself can enhance the production of the TNF-alpha in vitro, we studied the relationship between hypoxemia and activities of the TNF-alpha system, including circulating TNF-alpha and soluble TNF-receptors (sTNF-R; sTNF-R55 and -R75) levels, in 27 COPD patients and 15 age-matched healthy controls. The COPD patients showed a significant weight loss (body mass index = 18.1 +/- 2.8 versus 22.8 +/- 2.2 [mean +/- SD] kg/m(2); p < 0.0001. % fat = 16.3 +/- 5.9 versus 24.3 +/- 4.9 %; p < 0.001), and hypoxemia (Pa(O2 )= 62.2 +/- 9.5 versus 88.6 +/- 5.9 mm Hg; p < 0.0001) as compared with the healthy controls. Serum TNF-alpha (6.15 +/- 1.08 versus 5.41 +/- 1.60 pg/ml; p < 0.05) and plasma sTNF-R55 (1.15 +/- 0.49 versus 0.67 +/- 0.13 ng/ml; p < 0.0001) and sTNF-R75 (3.54 +/- 1.16 versus 2.25 +/- 0.43; p < 0.0001) levels were significantly higher in the COPD patients than in the healthy controls. There were inverse correlations between Pa(O(2)) and circulating TNF-alpha and sTNF-R levels in patients with COPD (TNF-alpha; r = -0.426, p = 0.0297; sTNF-R55: r = -0.587, p = 0.0027; sTNF-R75: r = -0.573, p = 0.0035). In addition, we found inverse correlations between sTNF-R levels and % fat in COPD patients (sTNF-R55: r = -0.442, p = 0.0272; sTNF-R75: r = -0. 484, p = 0.0155). TNF-alpha levels correlated well with sTNF-R levels (sTNF-R55: r = 0.488, p = 0.0127; sTNF-R75: r = 0.609, p = 0. 0019). These relationships were not observed in the healthy controls. These data suggest that systemic hypoxemia noted in patients with COPD is associated with activation of the TNF-alpha system in vivo, which may be a factor contributing to the weight loss in patients with the disease.

Aged↗

PubMed2000

Interleukin-8 gene repression by clarithromycin is mediated by the activator protein-1 binding site in human bronchial epithelial cells.

Macrolide antibiotics are known to be effective for the treatment of chronic inflammatory airway diseases including diffuse panbronchiolitis, chronic bronchitis, and bronchial asthma. Other than having antimicrobial activities, macrolides have antiinflammatory effects, such as the inhibition of cytokine production. In the present study we investigated the effects of clarithromycin (CAM) on interleukin (IL)-8 gene expression and protein levels, using the human bronchial epithelial cell line BET-1A. Northern blot analyses showed that CAM inhibited tumor necrosis factor (TNF)-alpha-induced IL-8 gene expression in a dose- and incubation time-dependent manner. The half-life of IL-8 messenger RNA transcripts in TNF-alpha-treated BET-1A cells did not change with CAM. Transfection studies with BET-1A cells, using fusion genes composed of the 5'-flanking sequences of the IL-8 gene and a luciferase reporter gene, demonstrated potent promoter activity in a 174-bp segment (-130 to +44 bp relative to the transcription start site). This segment includes activator protein (AP)-1 and nuclear factor (NF)-kappaB-like sites, and exhibited its strongest response to TNF-alpha. TNF-alpha-induced promoter activity in this segment showed a significant repression by CAM. However, a 156-bp segment (-112 to +44 bp) that does not include an AP-1 site but includes an NF-kappaB-like site did not show a significant repression of TNF-alpha-induced promoter activity by CAM. Mutation of the AP-1 binding site abrogated the suppression by CAM of TNF-alpha-induced enhancement of luciferase activity. In accord with promoter analyses, an electrophoretic mobility shift assay showed that CAM repressed AP-1 binding in TNF-alpha-treated BET-1A cells; however, TNF-alpha induced both AP-1 and NF-kappaB binding activities in BET-1A cells. These data suggest that macrolides such as CAM repress IL-8 gene transcription mainly via the AP-1 binding site in human bronchial epithelial cells. Our findings provide a novel mechanism for the antiinflammatory function of macrolides, implicating a target for the development of new drugs for treating chronic airway inflammation.

5' Untranslated Regions↗

PubMed2000

Vitamin D is an important factor in estrogen biosynthesis of both female and male gonads.

In the present study, the role of vitamin D in the regulation of estrogen synthesis in gonads was investigated. Vitamin D receptor null mutant mice showed gonadal insufficiencies. Uterine hypoplasia and impaired folliculogenesis were observed in the female, and decreased sperm count and decreased motility with histological abnormality of the testis were observed in the male. The aromatase activities in these mice were low in the ovary, testis, and epididymis at 24%, 58%, and 35% of the wild-type values, respectively. The gene expression of aromatase was also reduced in these organs. Elevated serum levels of LH and FSH revealed hypergonadotropic hypogonadism in these mice. The gene expressions of estrogen receptor alpha and beta were normal in gonads in these mice. Supplementation of estradiol normalized histological abnormality in the male gonads as well as in the female. Calcium supplementation increased aromatase activity and partially corrected the hypogonadism. When the serum calcium concentration was kept in the normal range by supplementation, the aromatase activity in the ovary increased to 60% of the wild-type level, but LH and FSH levels were still elevated. These results indicated that vitamin D is essential for full gonadal function in both sexes. The action of vitamin D on estrogen biosynthesis was partially explained by maintaining calcium homeostasis; however, direct regulation of the expression of the aromatase gene should not be neglected.

Animals↗

PubMed2000

Identification of novel human GH-1 gene polymorphisms that are associated with growth hormone secretion and height.

Height, which is partially determined by GH secretion, is genetically influenced. The purpose of this study was to identify polymorphisms in the GH-1 gene, which are associated with altered GH production. The subjects included prepubertal short children with GH insufficiency without gross pituitary abnormalities (n = 43), short children with normal GH secretion (n = 46), and normal adults (n = 294). A polymorphism in intron 4 (P-1, A or T at base 1663) was identified. Two additional polymorphic sites (P-2, T or G at base 218, and P-3, G or T at base 439) in the promoter region of the GH-1 gene were also identified and matched with the P-1 polymorphism (A or T, respectively) in more than 90% of the subjects. P-1, P-2, and P-3 were considered to be associated with GH production, and the results of P-2 are explained as a representative in this abstract. For example, the allele frequency of T at P-2 in prepubertal short children with GH insufficiency without gross pituitary abnormalities (58.1%) was significantly different from that in short children with normal GH secretion and normal adults (37.0% and 43.5%, respectively; P < 0.001). Furthermore, significant differences were observed in maximal GH peaks in provocative tests (11.1 vs. 18.2 ng/mL, P = 0.006), insulin-like growth factor I SD scores (SDS) (-2.4 vs. -0.8, P < 0.0001), and height (Ht) SDS (-3.7 vs. -3.0, P = 0/001) in children with the T/T or G/G genotypes at P-2, respectively. In the entire study group, significant differences in insulin-like growth factor SDS (T/T, -0.9; G/G, -0.2; P = 0.0009) and Ht SDS (T/T, -1.0; G/G, -0.4; P = 0.022) were observed between the T/T and G/G genotypes at P-2. These data indicate that GH secretion is partially determined by polymorphisms in the GH-1 gene, which explain some of the variations in GH secretion and Ht.

Adult↗

PubMed2000

Characterization of transactivational property and coactivator mediation of rat mineralocorticoid receptor activation function-1 (AF-1).

The autonomous activation function-2 (AF-2) in the mineralocorticoid receptor (MR) E/F domain is known to play a major role in the ligand-induced transactivation function of MR; however, it remained unclear about the transactivation function of its A/B domain. We therefore tried to characterize the MR A/B domain as the AF-1 and further studied the actions of known coactivators for AF-2 in the E/F ligand-binding domain in the function of the MR A/B domain. Deletion analyses of rat and human MRs revealed that the A/B domains harbor a transactivation function acting as AF-1. The MR mutant (E959Q) with a point mutation in helix 12, which causes a complete loss of MR AF-2 activity, still retained ligand-induced transactivation function, indicating a significant role for AF-1 in the full activity of the ligand-induced MR function. Among the coactivators tested to potentiate the MR AF-2, TIF2 and p300 potentiated the MR AF-1 through two different core regions [amino acids (a.a.) 1-169, a.a. 451-603] and exhibited functional interactions with the MR A/B domain in the cultured cells. However, such interactions were undetectable in a yeast and in an in vitro glutathione-S-transferase pull-down assay, indicating that the functional interaction of TIF2 and p300 with the MR A/B domain to support the MR AF-1 activity require some unknown nuclear factor(s) or a proper modification of the A/B domain in the cells.

Animals↗

PubMed2000

Molecular analysis of external genitalia formation: the role of fibroblast growth factor (Fgf) genes during genital tubercle formation.

The molecular mechanisms underlying the development of the external genitalia in mammals have been very little examined. Recent gene knockout studies have suggested that the developmental processes of its anlage, the genital tubercle (GT), have much in common with those of limb buds. The Fgf genes have been postulated as regulating several downstream genes during organogenesis. Fgf8 was expressed in the distal urethral plate epithelium of the genital tubercle (GT) together with other markers such as the Msx1, Fgf10, Hoxd13 and Bmp4 expressed in the mesenchyme. To analyze the role of the FGF system during GT formation, an in vitro organ culture system was utilized. It is suggested that the distal urethral plate epithelium of GT, the Fgf8-expressing region, regulates the outgrowth of GT. Ectopic application of FGF8 beads to the murine GT induced mesenchymal gene expression, and also promoted the outgrowth of the GT. Experiments utilizing anti-FGF neutralizing antibody suggested a growth-promoting role for FGF protein(s) in GT outgrowth. In contrast, despite its vital role during limb-bud formation, Fgf10 appears not to be primarily essential for initial outgrowth of GT, as extrapolated from Fgf10(-/-) GTs. However, the abnormal external genitalia development of Fgf10(-/-) perinatal mice suggested the importance of Fgf10 in the development of the glans penis and the glans clitoridis. These results suggest that the FGF system is a key element in orchestrating GT development.

Animals↗

PubMed2000

An efficient synthesis of 5-bromo-2-methoxy-6-methylaminopyridine-3carboxylic acid.

An efficient synthesis of 5-bromo-2-methoxy-6-methylaminopyridine-3-carboxylic acid (1), a carboxylic acid moiety of a potent dopamine D2 and D3 and serotonin-3 (5-HT3) receptors antagonist, (R)-5-bromo-N-(1-ethyl-4-methylhexahydro-1 ,4-diazepin-6-yl)-2-methoxy-6-methylaminopyridine-3-carboxamide, is described. Reaction of methyl 2,6-difluoropyridine-3-carboxylate (12) with methylamine in EtOH at -25 degrees C gave a mixture of methyl 2-fluoro-6-methylaminopyridine-3-carboxylate (13) and the regioisomer 14 in a ratio of 57 : 43. On the other hand, reaction of 12 and methyl 2,6-dichloropyridine-3-carboxylate (16) with sodium methoxide in tetrahydrofuran (THF) and CH2Cl2 provided the 2-methoxypyridine-3-carboxylic esters 20 and 23, respectively, as main products. Similar reaction of 16 in N,N-dimethylformamide (DMF) and MeOH proved to be highly regioselective for the 6-position. A much greater regioselectivity for substitution at the 6-position (>97%) was observed when 16 was treated with 4-methylbenzenethiolate anion in DMF (quantitative yield). After methoxylation of methyl 2-chloro-6-(4-methylbenzenethio)pyridine-3-carboxylate (25b) and successive oxidation of the 6-benzenethio moiety, nucleophilic substitution of the sulfoxide derivative 28 with methylamine gave the 6-methylamino derivative 8. Finally, bromination of 8 and alkaline hydrolysis produced the desired product 1 in an overall yield of 67%.

Dopamine Antagonists↗

PubMed2000

Heart disease in Friedreich's ataxia: observation of a case for half a century.

A case of Friedreich's ataxia was followed for 47 years, beginning in 1930; this patient had an abnormal electrocardiogram (flat or inverted T waves in leads II and III with prolonged QT interval) from the very beginning of the onset of neurological symptoms. Cardiac and neurological disturbances progressed slowly but steadily, and the patient died suddenly at the age of 67. The autopsy revealed typical findings of Friedreich's ataxia and hypertrophic cardiomyopathy with thickened left ventricular wall and myocardial fiber disarray. To the authors' knowledge, this is the longest continuous follow-up study of Friedreich's ataxia, and it will provide invaluable information on the natural history and development of the cardiac and neurological disorders in this condition.

Adult↗

PubMed2000

Direct polymerase chain reaction from whole blood without DNA isolation.

Blood and other animal fluids contain a variety of substances that inhibit the polymerase chain reaction (PCR), so that isolation of DNA is generally necessary prior to PCR. We have developed a novel reagent cocktail that effectively suppresses these inhibitory substances and makes DNA isolation from blood unnecessary for PCR. When this reagent was included in the PCR mixture, DNA fragments of the beta-globin gene could be efficiently amplified directly from human blood samples treated with various anticoagulants or PCR-inhibitory substances. We confirmed the usefulness of this cocktail by examining a large number of blood samples with various PCR primer sets. In addition to fresh blood, this method enabled PCR amplification from blood samples stored at 4 degrees C, -20 degrees C or -80 degrees C for a minimum of 1 year.

Animals↗

PubMed2000

Gene cloning, purification, and characterization of two cyanobacterial NifS homologs driving iron-sulfur cluster formation.

Iron-sulfur proteins are essential in the photosynthetic system and many other biological processes. We have isolated and characterized enzymes driving the formation of iron-sulfur clusters from Synechocystis sp. PCC6803. Two genes (slr0387 and sll0704), showing similarity to nifS of Azotobacter vinelandii, were cloned, and their gene products (SsCsdl and SsCsd2) were purified. They catalyzed the desulfuration of L-cysteine. Reconstitution of a [2Fe-2S] cluster of cyanobacterial ferredoxin proceeded much faster in the presence of L-cysteine and either of these enzymes than when using sodium sulfide. These results suggest that SsCsdl and SsCsd2 facilitate the iron-sulfur cluster assembly by producing inorganic sulfur from L-cysteine. Synechocystis sp. PCC6803 has no gene coding for a protein with similarity to the N-terminal domain of NifU of A. vinelandii, which is believed to cooperate with NifS to assemble iron-sulfur clusters. Thus, the cluster formation in the cyanobacterium probably proceeds through a mechanism that is different from that in A. vinelandii.

Bacterial Proteins↗

PubMed2000

Glycosidic fraction of flue-cured tobacco leaves: its separation and component analysis.

The fraction containing glycosidic components was separated from flue-cured tobacco (Nicotiana tabacum L.) leaves by a facile method. Some components of the fraction were isolated and elucidated to be syringin, coniferin, cichoriin, benzyl-beta-D-glucoside, Blumenol A-beta-D-glucoside, and 5,6-epoxy-5,6-dihydro-3-hydroxy-beta-ionyl-beta-D-glucoside. Syringin and coniferin were detected in the Nicotiana species for the first time.

Benzopyrans↗

PubMed2000

Organ specificity of the structural organization and fine distribution of lymphatic capillary networks: histochemical study.

Histochemical studies of the microcirculatory system were reviewed with regard to the organ specificity of the structural organization and fine distribution of the lymphatic capillary network. The lymphatics and blood vessels are characterized by an enzyme-histochemical method using 5'-nucleotidase (5'-Nase), alkaline phosphatase (ALPase) and/or diaminopeptidase (DAPase) staining in addition to an immunohistochemical method. The 5'-Nase-positive lymphatic vessels can be distinguished histochemically from arterial and venous vessels based on ALPase and DAPase activity, respectively. The specificity and localization of the enzyme reactions were confirmed by comparative histochemical studies of the same specimen with light microscopy and scanning or transmission electron microscopy. These histochemical methods are discussed in relation to their ability to demonstrate the organ specificity of vascular networks under normal and pathological conditions.

Animals↗

PubMed2000

Murine stromal cell line HESS-5 maintains reconstituting ability of Ex vivo-generated hematopoietic stem cells from human bone marrow and cytokine-mobilized peripheral blood.

Human bone marrow (BM) or mobilized peripheral blood (mPB) CD34(+) cells have been shown to loose their stem cell quality during culture period more easily than those from cord blood (CB). We previously reported that human umbilical CB stem cells could effectively be expanded in the presence of human recombinant cytokines and a newly established murine bone marrow stromal cell line HESS-5. In this study we assessed the efficacy of this xenogeneic coculture system using human BM and mPB CD34(+) cells as materials. We measured the generation of CD34(+)CD38(-) cells and colony-forming units, and assessed severe-combined immunodeficient mouse-repopulating cell (SRC) activity using cells five days after serum-free cytokine-containing culture in the presence or the absence of a direct contact with HESS-5 cells. As compared with the stroma-free culture, the xenogeneic coculture was significantly superior on expansion of CD34(+)CD38(-) cells and colony-forming cells and on maintenance of SRC activity. The PKH26 study demonstrated that cell division was promoted faster in cells cocultured with HESS-5 cells than in cells cultured without HESS-5 cells. These results indicate that HESS-5 supports rapid generation of primitive progenitor cells (PPC) and maintains reconstituting ability of newly generated stem cells during ex vivo culture irrespective of the source of samples. This xenogeneic coculture system will be useful for ex vivo manipulation such as gene transduction to promote cell division and the generation of PPC and to prevent loss of stem cell quality.

ADP-ribosyl Cyclase↗

PubMed2000

Ultrastructural and histochemical characterization of special muscle cells in the monkey small intestine.

The ultrastructure, three-dimensional arrangement, and histochemical features of special muscle cells in the monkey small intestine were investigated. The cells formed a special layer separated from the main part by a connective tissue space along the submucosal surface of the circular muscle coat. Scanning electron microscopy using alkali maceration demonstrated this inner sublayer to be a continuous thin sheet consisting of irregularly-shaped muscle cells equipped with many cytoplasmic projections and caveolae. Other ultrastructural features included direct contact with interstitial cells, due to their close association with nerve fibers of the deep muscular plexus. Histochemical examination revealed significant alkaline phosphatase activity and immunoreactivity for vascular smooth muscle alpha actin in these muscle cells, whereas the ordinary circular muscle cells were immunopositive for enteric smooth muscle gamma actin. These findings suggest that the special muscle cells play an important role in regulating the radial stretch of the monkey small intestinal wall.

Actins↗

PubMed2000

Antiphospholipid syndrome with cortical blindness resulting from infarction around the posterior cerebral artery in an elderly woman.

An 87-year-old woman with antiphospholipid syndrome accompanied by cortical blindness and thalamic syndrome resulting from infarction of the posterior cerebral artery is reported. She was hospitalized because of laceration of the head. Two months later, she complained of loss of visual acuity, sharp pain and numbness involving the left half of the body except her face. New right posterior lobe infarction and the existence of old left infarctions were confirmed by serial CT scans. Helical CT scan revealed embolization of the posterior cerebral artery with atherosclerotic stenosis. Serological examination showed biologically false-positive and positive findings for lupus anticoagulant. She was treated with warfarin potassium and clonazepam.

Aged↗

PubMed2000

Structural organization and fine distribution of lymphatic vessels in periodontal tissues of the rat and monkey: a histochemical study.

The structural organization and fine distribution of lymphatic vessels in the periodontal tissues (gingiva, periodontium and alveolar process) were examined by light and electron microscopy using an enzyme-histochemical method. Whole mount preparations of periodontal membranes peeled from the teeth and cryostat sections of normal or decalcified tissues treated with EDTA were double-stained using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) and examined by light microscopy. This staining procedure allowed the lymphatic vessels in the periodontal tissue to be differentiated from blood vessels. Well-developed 5'-Nase-positive lymphatics were observed in the gingiva and periodontium. The histochemical aspects of 5'-Nase activity in lymphatic vessels are discussed in detail, with special reference to the supply of Mg++ ions. A network of 5'-Nase-positive lymphatics was observed in whole mount preparations of the periodontal membrane for the first time. This network was also observed in the tissue sections. More 5'-Nase-positive lymphatics were seen in the root area of the periodontium than in the cervical area. 5'-Nase-positive lymphatics in residual tissue blocks remaining after cryostat sectioning and in whole mount preparations were highlighted with good contrast and resolution on backscattered electron images produced by scanning electron microscopy. Dense granular precipitations resulting from the 5'-Nase reaction were observed on the luminal surface of the lymphatic endothelial cells as well as on the basal side but were absent in the blood vessels.

5'-Nucleotidase↗

PubMed2000

Coordinate regulation of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 expression in human vascular smooth muscle cells.

The expression of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) by human vascular smooth muscle cells (SMC) was monitored as a function of the phenotypic modulation in vitro. Cell phenotype was manipulated by varying serum concentration and cell density. Synthetic phenotype was characterized by a minimum expression of the contractile proteins and a maximal proliferation rate. Contractile phenotype was quiescent and expressed a maximal level of contractile proteins. Synthetic cells expressed the highest levels of both MMP-1 and TIMP-1 and displayed maximal collagenolytic activity. No significant change was detected in MMP-2 expression or catalytic activity. Enzyme immunoassays revealed that MMP-1 expression fell by 77+/-2.4-95+/-0.5%, and that of TIMP-1 by 34+/-0.5-59+/-1.9%, as the cells acquired a contractile phenotype. The level of the MMP-1/TIMP-1 complex was similarly reduced by 78+/-2.9-85+/-1.6%. These data demonstrate that the expression of MMP-1 and TIMP-1 are coordinately regulated with SMC phenotype.

Adult↗

PubMed2000

Increased midkine expression in hepatocellular carcinoma.

CONTEXT: Midkine (MK) is a novel heparin-binding growth factor whose gene was identified in embryonal carcinoma cells in early stages of retinoic acid-induced differentiation. OBJECTIVE: To examine the overexpression of MK in hepatocellular carcinoma (HCC). METHODS: Seventy-seven primary HCC specimens from patients aged 17 to 72 years (63 men and 14 women) were examined. Histologically, 16 cases of HCC were classified as the well-differentiated type, 50 cases as the moderately differentiated type, and 11 cases as the poorly differentiated type. Immunohistochemical analysis was performed using a rat immunoglobulin G2a monoclonal antibody against the carboxyl terminal region of human MK. In situ hybridization was also performed on 20 HCC samples. RESULTS: We successfully applied this monoclonal antibody against MK to analyze archival paraffin sections. The cancer tissues showed a positive reaction to this antibody, in which there was an intense reaction in their cytoplasm. Approximately one third of the individuals with HCC (26/77) had tumor cells that expressed MK, and these were classified into the following types: moderately differentiated (20/50), well differentiated (3/16), and poorly differentiated (3/11). The in situ hybridization analysis revealed that the signals of MK transcripts were found in the cytoplasm of the cancer cells; the distribution and localization of the MK transcripts' signals determined by in situ hybridization analysis were similar to those obtained by immunohistochemical analysis. CONCLUSIONS: Hepatocellular carcinoma expressed increased MK at the messenger RNA and protein level.

Adolescent↗