Search PubMed⌕ Search

Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 271 records · Page 15Linked to original sources
PubMed1997

The chromosome location of the human homolog of the mouse mammary tumor-associated gene INT6 and its status in human breast carcinomas.

The INT6 gene is a common integration site for the mouse mammary tumor virus in mouse mammary tumors. We have determined that the human homolog of INT6 is located on chromosome region 8q22-q23. A processed INT6 pseudogene is located on chromosome 6q. INT6 is composed of 13 exons that span 45 kb of genomic DNA. The deduced amino acid sequence of the gene product is identical to the mouse protein and contains three potential translation start signals. We have examined 100 primary breast carcinoma DNAs for evidence of genetic alteration affecting INT6. Loss of heterozyosity (LOH) was detected in 11 of 39 (28%) of the tumor samples informative for a polymorphic sequence in intron 7 of INT6. Since single-strand conformation and hybrid mismatch analysis of the remaining allele in these tumor DNAs failed to detect any mutations, we conclude that the target gene for LOH must be closely linked to INT6.

Animals↗
PubMed1997

Post-transcriptional regulation of LTC4 synthase activity by retinoic acid in rat basophilic leukemia cells.

Calcium ionophore-stimulated production of leukotriene (LT) C4 was enhanced by 16- to 26-h incubation with retinoic acid (RA) in rat basophilic leukemia-1 cells. Production of LTC4 by enzyme assay using cell lysates as the enzyme source and LTA4 as the substrate was also enhanced by RA-treatment. Production of LTB4 was not enhanced under these two experimental conditions, suggesting the preferential activation of LTC4 synthase activity. The RA-induced enhancement of LTC4 synthesis by the cells was suppressed by co-incubation with dexamethasone (DEX) or cyclosporine A (CSA). However, the expression of mRNA for LTC4 synthase was not affected by the exposure to RA, DEX or CSA. These results indicate that RA-induced enhancement of LTC4 production and its inhibition by DEX and CSA was determined by post-transcriptional regulation of LTC4 synthase.

Animals↗
PubMed1997

Immunohistochemical detection of imidazolone, a novel advanced glycation end product, in kidneys and aortas of diabetic patients.

To investigate the role of the Maillard reaction in the pathogenesis of diabetic complications, we produced several clones of monoclonal antibodies against advanced glycation end products (AGEs) by immunizing mice with AGE-modified keyhole limpet hemocyanin, and found that one clone (AG-1) of the anti-AGE antibodies reacted specifically with imidazolones A and B, novel AGEs. Thus, the imidazolones, which are the reaction products of the guanidino group of arginine with 3-deoxyglucosone (3-DG), a reactive intermediate of the Maillard reaction, were found to be common epitopes of AGE-modified proteins produced in vitro. We determined the erythrocyte levels of imidazolone in diabetic patients using ELISA with the monoclonal anti-imidazolone antibody. The imidazolone levels in the erythrocytes of diabetic patients were found to be significantly increased as compared with those of healthy subjects. Then we studied the localization of imidazolone in the kidneys and aortas obtained from diabetic patients by immunohistochemistry using the antibody. Specific imidazolone immunoreactivity was detected in nodular lesions and expanded mesangial matrix of glomeruli, and renal arteries in an advanced stage of diabetic nephropathy, as well as in atherosclerotic lesions of aortas. This study first demonstrates the localization of imidazolone in the characteristic lesions of diabetic nephropathy and atherosclerosis. These results, taken together with a recent demonstration of increased serum 3-DG levels in diabetes, strongly suggest that imidazolone produced by 3-DG may contribute to the progression of long-term diabetic complications such as nephropathy and atherosclerosis.

Adolescent↗
PubMed1997

Coronary artery aneurysms detected with ultrafast computed tomography.

A 25-year-old Japanese woman was admitted due to acute inferior myocardial infarction. Coronary angiography showed complete occlusion of the proximal right coronary artery and vague calcification distal to the complete occlusion. Using ultrafast computed tomography, two coronary artery aneurysms in the right coronary artery that could not be detected by coronary angiography were visualized.

Adult↗
PubMed1997

Adverse effects of tumour necrosis factor in cyclophosphamide-treated mice subjected to gut-derived Pseudomonas aeruginosa sepsis.

To evaluate the role of tumour necrosis factor (TNF) in gut-derived sepsis, mice were given Pseudomomas aeruginosa strain D4 by bacterial suspension in their drinking water during which time ampicillin (200 mg/kg) was given to disrupt the normal indigenous bacterial flora. Cyclophosphamide was additionally administered to induce bacterial translocation of the P. aeruginosa that had colonized the gastrointestinal tract, and thereby to cause gut-derived sepsis. In this model, TNF-alpha was detected in serum from the next day after the second cyclophosphamide administration, increasing to level of 3 ng/ml in lethal conditions. Average serum TNF-alpha level was significantly higher in mice with bacteraemia than in those without bacteraemia. Treatment with 0.8 microg/kg of recombinant human TNF-alpha (rhTNF-alpha) did not affect the mortality, whereas administration of either 4 and 20 microg/kg of rhTNF-alpha significantly increased the mortality rate in comparison with saline-treated mice. Bacterial counts in liver and blood were significantly higher in 20 microg/kg of rhTNF-alpha treated mice than in saline-treated mice. Treatment with murine anti-TNF-alpha monoclonal antibody significantly reduced the mortality from septic infection. We conclude that TNF-alpha may facilitate bacterial translocation and causes deterioration of gut-derived sepsis due to P. aeruginosa in mice.

Animals↗
PubMed1997

Effect of ankle-foot orthosis on active ankle moment in patients with hemiparesis.

The paper investigates the effect of dorsi/plantar rigidity and the initial angle of ankle-foot orthoses (AFOs) on the moment generated by ankle musculature (referred to as active ankle moment) during gait in patients with hemiparesis. In the early stance phase, the active ankle moment in the direction of dorsiflexion is negligible, and AFOs play an important role in supplementing weak dorsiflexion. In mid to late stance, the moment generated by AFOs is very small compared with the active ankle moment in the direction of plantarflexion. AFOs therefore play only a limited role in assisting plantar flexors during this period. The active ankle moment in the direction of plantarflexion varies significantly with changes in the rigidity and initial angle of AFOs in 11 out of 20 subjects. The implication of this finding is discussed in relation to the need for dynamic matching of AFOs in individual patients with hemiparesis.

Adult↗
PubMed1997

Evaluation of abdominal lymphadenopathy in children by ultrasonography.

BACKGROUND: There may be uncertainty as to whether enlarged abdominal lymph nodes (LNs) in children are normal or abnormal. OBJECTIVE: To compare, by ultrasonography (US), enlarged abdominal LNs in healthy children with those in children with acute abdominal pain or acute gastroenteritis. MATERIALS AND METHODS: One hundred and twenty-two asymptomatic children were selected by questionnaire and compared with 44 children with acute abdominal pain of unknown origin and 27 children with acute gastroenteritis. The number of LNs, their location, their shape and the presence of tenderness as detected by finger compression of each LN were evaluated. The children were divided into four groups according to age: 0-2, 3-6, 7-10, and 11-15 years. RESULTS: LNs were detected in the ileo-caecal and/or para-aortic areas in almost all of the asymptomatic children. The number of large LNs ( > 10 mm) in the para-aortic areas was higher in the older children (>/= 7 years of age) than in the younger children ( </= 6 years of age) (P < 0.05). The number of spindle-shaped LNs (ratio of long- to short-axis diameter >/= 2.0) was increased in the older children. The number of LNs was not increased in the children with acute abdominal pain. The size of the LNs was largest in the children with acute gastroenteritis, followed by the children with acute abdominal pain and the asymptomatic children (P < 0.001). Although the shape of the LNs was no different among the three groups of children, the frequency of round-shaped LNs (ratio of long- to short-axis diameter < 2.0) was greater in the older children with acute abdominal pain or acute gastroenteritis than in the asymptomatic children (P < 0.01). The number of LNs with tenderness detected by finger compression was significantly greater in the children with acute abdominal pain and acute gastroenteritis than in the asymptomatic children (P < 0.0001). CONCLUSION: The number of large and round-shaped LNs with tenderness tended to be increased in the children with acute gastroenteritis and acute abdominal pain. There is no clear specificity of LN enlargement in the children with acute abdominal pain, and the main challenge is to diagnose or estimate the organic pathology by US, regardless of the presence of lymphadenopathy.

Abdomen↗
PubMed1997

The R40H mutation in a late onset type of human ornithine transcarbamylase deficiency in male patients.

Ornithine transcarbamylase (OTC) deficiency is an X-linked trait and is one of the most frequent of the inherited urea cycle enzyme deficiencies. Most male patients with OTC deficiency develop a hyperammonemic crisis and die in the neonatal period or in early infancy. In contrast to those patients, in some male patients the disease first becomes overt in adolescence or during the reproductive age period. In the present report, we describe six such male patients who first developed clinical signs at ages ranging from 6 to 58 years, all of whom came from a limited area of the northern part of Kyushu Island in southern Japan. The mutation analysis disclosed a R40H mutation in exon 2 of the OTC gene in each of these patients. Transmission of this mutant gene through paternal lineage as well as through maternal lineage was documented in one family. The levels of mRNA of the mutant OTC gene expressed in transfected Cos 1 cells and in the liver tissue obtained by biopsy in one patient were both similar to those of the wild-type gene. The activity of the mutant OTC was, however, decreased to a level of 28% of the wild-type OTC, and the levels of the mutant OTC protein expressed in Cos 1 cells were decreased, as assessed by western blot analysis. Apparent Km values of the mutant enzyme for ornithine (1.1 mM) and carbamylophosphate (2.0 mM) were similar to those of the wild-type enzyme. Both enzymes gave similar pH-dependency profiles, giving a maximal activity at pH 7.8-7.9. Activity of wild-type OTC expressed in Cos 1 cells did not change after five cycles of freezing and thawing, whereas that of the mutant OTC decreased to 17% by this treatment. These results suggest that deficiency is due to inactivation of the mutant OTC under certain conditions.

Adolescent↗
PubMed1997

Effects of clobenpropit (VUF-9153), a histamine H3-receptor antagonist, on learning and memory, and on cholinergic and monoaminergic systems in mice.

The effects of clobenpropit (VUF-9153), a potent histamine H3-receptor antagonist, on a scopolamine-induced learning deficit in the step-through passive avoidance test was studied in mice. Clobenpropit (10 and 20 mg/kg) alone showed a tendency to ameliorate the scopolamine-induced learning deficit, and clobenpropit (10 mg/kg) in combination with zolantidine (20 mg/kg), a histamine H2-receptor antagonist, ameliorated the scopolamine-induced effect. This ameliorating effect was antagonized by (R)-alpha-methylhistamine (20 mg/kg), a histamine H3-receptor agonist and pyrilamine (20 mg/kg), a histamine H1-receptor antagonist, suggesting that clobenpropit in combination with zolantidine showed the ameliorating effect via histamine H3 receptors and/or histamine H1 receptors. We also studied the effects of clobenpropit on cholinergic and monoaminergic systems. Clobenpropit did not show any significant effect on these neuronal systems except the activation of noradrenergic system. The present results suggest that the effect of clobenpropit might be partially involved with the activation of noradrenergic system, and the histaminergic system may play certain important roles in learning and memory.

Acetylcholine↗
PubMed1997

Primary culture and expression of cytokine mRNAs by lipopolysaccharide in bovine Kupffer cells.

Kupffer cells are sessile tissue macrophages that have a role in liver defense against endogenous endotoxins. Because little information is available on the role of bovine Kupffer cells, we developed a primary culture method to investigate the function of bovine Kupffer cells. Kupffer cells were isolated from the caudate lobe of calf liver by perfusion with collagenase and pronase. Then, the cells were purified by gradient centrifugation followed by counterflow centrifugal elutriation. With the methods, a mean number of 1.5 x 10(6) Kupffer cells with a final viability of over 98% was obtained from 1 g of the liver. Over 95% of the isolated cells were positive for non-specific esterase activity and had surface molecule of CD68. The cultured Kupffer cells expressed mRNAs of tumor necrosis factor-alpha, interleukin (IL)-1 alpha, IL-1 beta and IL-6 by stimulation for 3 h with lipopolysaccharide. The primary culture of bovine Kupffer cells could be useful to investigate the systemic inflammatory response in bovine liver.

Animals↗
PubMed1997

The Chinese herbal medicine, shinpi-to, inhibits IgE-mediated leukotriene synthesis in rat basophilic leukemia-2H3 cells.

We examined the action of Shinpi-To (Formula divinita; TJ-85), a granular extract of seven Chinese medicinal herbs that is used in treating childhood asthma, on the leukotriene synthesis in rat basophilic leukemia-2H3 cells (RBL-2H3 cells). IgE-loaded cells were stimulated with anti-IgE serum in the presence or absence of Shinpi-To. Released LTC4 and LTB4 were measured by radioimmunoassay (RIA). Shinpi-To significantly inhibited IgE-mediated synthesis of leukotriene (LT)C4 and LTB4. To identify the inhibitory sites, we investigated the action of this extract on four synthetic enzymes, phospholipase A2 (PLA2), 5-lipoxygenase (5-LO). LTC4 synthase, and LTA4 hydrolase. Shinpi-To inhibited the A23187-stimulated release of [3H]arachidonic acid (AA) from the cell membrane, reflecting an effect on PLA2 activity. It also suppressed production of LTC4 and LTB4 when cell lysates were incubated with AA as substrate. It did not inhibit the production of LTC4 and LTB4 when LTA4-free acid was used as the substrate. Shinpi-To did not inhibit the IgE-mediated increase of intracellular Ca2+ ([Ca2+]i) concentration. Results indicate that Shinpi-To inhibits LT synthesis by inhibiting PLA2 and 5-LO activities without affecting the mobilization of [Ca2+]i.

Analysis of Variance↗
PubMed1997

Unbalanced production of interleukin-5 and interleukin-2 in children with atopic dermatitis.

BACKGROUND: Cytokines, such as interleukin (IL)-5, produced by T helper type 2 Th2) cells appear to play an important role in the inflammatory processes associated with atopic dermatitis. The roles of cytokines produced by Th1 cells remain controversial. OBJECTIVE: We examined IL-5 and IL-2 mRNA abundance in and protein production by peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis and compared those from controls. METHODS: Peripheral blood mononuclear cells were isolated from six children with atopic dermatitis and six control children, and stimulated with both phytohemaggulutinin (PHA) and phorbol 12-myristate 13-acetate (PMA). The abundance of IL-5 and IL-2 mRNA in PBMCs was measured by reverse transcription-polymerase chain reaction analysis. The production of IL-5 and IL-2 by PBMCs was also determined by enzyme-linked immunosorbent assay. RESULTS: After incubation with PHA and PMA, PBMCs from atopic children showed significantly higher IL-5 mRNA abundance (P < .05) and IL-5 production (P < .01), as well as a lower amount of IL-2 mRNA (P = .056) and IL-2 production (P < .05) than those from healthy controls. The time course of changes in IL-5 mRNA abundance induced by PHA and PMA in PBMCs from atopic children differed markedly from that observed with healthy controls, whereas the time course of changes in IL-2 mRNA abundance were similar between the two groups. CONCLUSIONS: The increased IL-5 and decreased IL-2 production observed with PBMCs from children with atopic dermatitis may underlie the activation of eosinophils and high serum immunoglobulin E concentrations also apparent in such individuals. An imbalance in the number and activity of Th1 and Th2 cells is likely to be responsible for the abnormal pattern of cytokine production in atopic dermatitis.

Adolescent↗
PubMed1997

High-performance liquid chromatographic assay of arachidonic acid metabolites from cultured rat glial cells.

Although various methods can be used for detection of arachidonic acid (AA) metabolites, only few of them allow rapid and precise analysis of both cyclooxygenase and lipoxygenase metabolites in a single assay. We have developed a simple and rapid method to evaluate overall profiles of AA metabolites produced by primary cultured glial cells from newborn rats by using reversed-phase, high-performance liquid chromatography (RP-HPLC) and on-line radioisotope detection.

Animals↗
PubMed1997

Amyloid beta 2-microglobulin is modified with imidazolone, a novel advanced glycation end product, in dialysis-related amyloidosis.

We have recently demonstrated by immunohistochemistry that amyloid beta 2-microglobulin (beta 2m) is modified with advanced glycation end products (AGEs) in dialysis-related amyloidosis (DRA). To further investigate the role of the Maillard reaction in the pathogenesis of DRA, we produced a monoclonal antibody to imidazolone, a novel AGE, and a reaction product of arginine and 3-deoxyglucosone (3-DG) which was accumulated in uremic serum. Then we determined the localization of imidazolone in the amyloid tissues by immunohistochemistry using the antibody. The connective tissues in carpal tunnel and ligamentum flavum were obtained from six patients with carpal tunnel syndrome and two patients with destructive spondyloarthropathy. Imidazolone was localized to all the beta 2m-positive amyloid deposits in these patients. Western blotting using the antibody demonstrated that beta 2m extracted from the synovium amyloid of hemodialysis patients was modified with imidazolone. Further, beta 2m isolated from the blood ultrafiltrate of hemodialyzed patients was also modified with imidazolone. In vitro incubation of beta 2m with 3-DG produced imidazolone-modified beta 2m. In conclusion, amyloid tissue beta2m is modified with imidazolone in patients with DRA. 3-DG accumulating in uremic serum may be involved in the modification of beta 2m with imidazolone.

Aged↗