Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 199 records · Page 11Linked to original sources

PubMed1995

Adrenomedullin inhibits the secretion of cytokine-induced neutrophil chemoattractant, a member of the interleukin-8 family, from rat alveolar macrophages.

This study was undertaken to determine the effects of adrenomedullin (AM) on the secretion of cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 family, from lipopolysaccharide-stimulated rat alveolar macrophages in vitro. AM significantly increased cAMP levels in alveolar macrophages in a dose-dependent fashion. On the other hand, AM significantly inhibited CINC secretion from alveolar macrophages in a dose-dependent fashion, and 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) also significantly inhibited CINC secretion. These findings suggest that AM may play important roles in the regulation of airway inflammation via a cAMP-dependent mechanism.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1995

Cytoskeletal reorganization of human platelets induced by the protein phosphatase 1/2 A inhibitors okadaic acid and calyculin A.

Okadaic acid (OA) and calyculin A (CLA), which are potent and specific inhibitors of serine/threonine protein phosphatases type 1 and 2A, have been shown to induce drastic changes in platelet morphology. The aim of this study was to analyse the molecular mechanisms of OA- or CLA-induced cytoskeletal reorganization, with a specific focus on microtubules and actin filaments. Confocal fluorescence microscopy revealed that OA or CLA altered the distribution of microtubules from marginal band arrangements to homogeneous patterns, consistent with the transmission-electron-microscopic finding that microtubules were fragmented and redistributed into pseudopod-like processes. In thrombin-activated platelets, OA or CLA induced extremely long pseudopods containing an array of microtubules and actin filaments, and a condensed mass of actin filaments in the centre of platelets. OA or CLA induced the constriction of actin filaments without an increase in filamentous (F)-actin, and also rather significantly inhibited actin polymerization in thrombin-activated platelets. Furthermore, neither OA or CLA enhanced phosphorylation of myosin light chain (MLC). By immunoprecipitation of platelet lysate with anti-alpha-tubulin antibody, a 90 kDa protein was co-precipitated with tubulin and was predominantly phosphorylated in the presence of OA. As the time-dependent phosphorylation of 90 kDa protein correlated well with the reorganization of microtubules, these data suggest that phosphorylation and dephosphorylation of this protein might play a role in the regulation of microtubule organization. These findings indicate that OA or CLA induces reorganization of microtubules and actin filaments via the phosphorylation of a microtubule-associated 90 kDa protein and an MLC-phosphorylation-independent mechanism. mechanism.

Actins↗

PubMed1995

Involvement of protein phosphatase-1 in cytoskeletal organization of cultured endothelial cells.

The phosphorylation and dephosphorylation of cytoskeletal proteins regulate the shape of eukaryotic cells. To elucidate the role of serine/threonine protein phosphatases (PP) in this process, we studied the effects of calyculin A (CLA), a potent and specific inhibitor of protein phosphatases 1 (PP-1) and 2A (PP-2A) on the cytoskeletal structure of cultured human umbilical vein endothelial cells (HUVECs). The addition of CLA (5 min) caused marked alterations in cell morphology, such as cell constriction and bleb formation. Microtubules and F-actin were reorganized, becoming markedly condensed around the nucleus. Although the fluorescence intensity of phosphoamino acids was not significantly different according to immunocytochemistry between cells with and without CLA, polypeptides of 135, 140, 158, and 175 kDa were specifically phosphorylated on serine and/or threonine residues. There was no significant effect on tyrosine residues. The effects of CLA on cytoskeletal changes and protein phosphorylation were almost completely inhibited by the non-selective kinase inhibitor, K-252a. The effect of CLA on cell morphology was at least 100 times more potent than that of okadaic acid, consistent with the inhibitory potency against PP-1. The catalytic subunit of PP-1 was also identified in HUVECs by Western blotting with its monoclonal antibody antibody. These results suggest that PP-1 is closely involved in sustaining the normal structure of the cytoskeleton.

Actins↗

PubMed1995

Regulation of apoptosis of interleukin 2-dependent mouse T-cell line by protein tyrosine phosphorylation and polyamines.

We examined the effect of inhibitors of tyrosine kinase and tyrosine phosphatase on DNA fragmentation, protein tyrosine phosphorylation, and polyamine metabolism in the murine T-cell line CTLL-2. When cells were exposed to herbimycin A, a specific inhibitor of tyrosine kinase (Uehara et al., 1989, Biochem. Biophys. Res. Commun., 163:803-809), in the presence of interleukin 2 (IL-2), DNA was degraded into oligonucleosomal fragments in a dose-dependent fashion. Genistein, another inhibitor of tyrosine kinase (Akiyama et al., 1987, J. Biol. Chem., 262:5592-5596), had similar effects. Exposure of CTLL-2 cells to vanadate, a tyrosine phosphatase inhibitor, blocked with the DNA fragmentation induced by herbimycin A. Tyrosine phosphorylation of 55 Kd protein was inhibited by herbimycin A, and the inhibition was reduced by vanadate. Ornithine decarboxylase (ODC) activity decreased rapidly after herbimycin A was added to CTLL-2 cell cultures, while vanadate increased ODC activity. The exogenous addition of putrescine or spermine, but not that of spermidine, attenuated herbimycin A-induced DNA fragmentation. These findings suggest that phosphorylation of tyrosine residues of 55 Kd protein prevents DNA fragmentation and that polyamines are involved in regulation of apoptosis.

Animals↗

PubMed1995

Influence of a delay on latissimus dorsi muscle flap blood flow.

The regional and total blood flow of canine latissimus dorsi muscle flaps (LDMFs) were examined to study the effect of a delay procedure, ligation of the perforators, before complete flap elevation. The regional blood flow of the middle and distal regions of the nondelayed LDMFs was poor and significantly lower than the proximal region at rest. The regional blood flow during the exercise test was improved and significantly higher in the middle (62% increase) and distal regions (187% increase) of the delayed LDMFs as compared with the nondelayed LDMFs. The mean total blood flow of the delayed LDMFs was 14 mL.min-1.100(-1) g at rest, increased to 30 mL.min-1.100(-1) g during exercise tests with intermittent burst electrical stimulation, and was maximal at 40 mL.min-1.100(-1) g immediately after the exercise. The phasic arterial blood flow of the delayed LDMFs was inhibited during contraction at 9 mL.min-1.100(-1) g, whereas it was 44 mL.min-1.100(-1) g during relaxation. In contrast, the phasic venous blood flow was accentuated during contraction to 32 mL.min-1.100(-1) g compared with 16 mL.min-1.100(-1) g during relaxation.

Animals↗

PubMed1995

Clinical evaluation on combined administration of oral prostacyclin analogue beraprost and phosphodiesterase inhibitor cilostazol.

Among various oral antiplatelets, a combination of a novel prostacyclin analogue beraprost (BPT) and a potent phosphodiesterase inhibitor cilostazol (CLZ) may result in untoward clinical effects due to possible synergistic elevation of intracellular cAMP (cyclic adenosine 3',5'-monophosphate). Thereby, a clinical study of the combined administration of the two agents was attempted. Twelve healthy volunteers were assigned to take BPT/CLZ in the following schedule; BPT: 40 micrograms at day 1 and 120 micrograms t.i.d. from day 7 to 14, CLZ: 200 mg t.i.d. from day 3 to 14. At various time intervals, physical examination and blood collection for ex vivo platelet aggregation and determination of intraplatelet cAMP were performed. Throughout the observation period, no significant alteration in vital signs was observed. Seven out of 12 subjects experienced headache of a short duration accompanying facial flush in one and nausea in one, especially after ingestion of CLZ. All of these symptoms, probably caused by the vasodilating effect of the two agents, were of mild degree and no special treatment was required. Intraplatelet cAMP content was gradually but significantly increased to 9.84 +/- 4.59 pmol per 10(9) platelets at day 14 in comparison with the initial value (6.87 +/- 2.25 pmol). The platelet aggregability was significantly suppressed at various time intervals but no additive or synergistic inhibitory effect by the combined administration was noted. In conclusion, the combined administration of BPT/CLZ is safe at doses used in the study, though the beneficial clinical effect of the combined administration has yet to be elucidated.

Adult↗

PubMed1995

Inhibition of intestinal tumor development in rat multi-organ carcinogenesis and aberrant crypt foci in rat colon carcinogenesis by 22-oxa-calcitriol, a synthetic analogue of 1 alpha, 25-dihydroxyvitamin D3.

The modifying effects of 22-oxa-calcitriol (OCT), a synthetic analog of 1 alpha,25-dihydroxyvitamin D3, were assessed in a multi-organ carcinogenesis model using male F344 rats initially treated with five kinds of carcinogens. In experiment 1 the rats were given OCT intraperitoneally at doses of 30 micrograms/kg (25 rats) or 3 micrograms/kg (25 rats), three times a week for 24 weeks after initial carcinogen exposure over 4 weeks and a 2 week non-treatment period. Twenty-two rats received the five carcinogens and were given the vehicle intraperitoneally as a control. A further group of 10 rats was given the 30 micrograms/kg dose of OCT without prior carcinogen application. At the end of the total observation period of 30 weeks the carcinoma incidence in the small intestine of rats given 30 micrograms/kg OCT after carcinogen treatment was 0%. This incidence was significantly smaller when compared with the control group. The incidence of large intestine carcinomas in the 30 micrograms/kg OCT group showed a tendency to decrease. The numbers of small and large intestinal carcinomas per rat were also significantly lower in the group given 30 micrograms/kg OCT than after 3 micrograms/kg OCT or carcinogens alone. Attention was, therefore, focused on colon carcinogenesis and in experiment 2 30 micrograms/kg OCT administered six times a week to rats for 8 weeks after the last injection of N,N'-dimethylhydrazine (DMH) exposure. OCT significantly reduced the formation of DMH-induced aberrant crypt foci, considered to be putative preneoplastic lesions. In experiment 3 30 micrograms/kg OCT was administered six times a week to rats for 4 weeks without prior carcinogen treatment. The proliferating cell nuclear antigen labeling index for the colonic epithelium of rats given 30 micrograms/kg OCT was decreased. Ornithine decarboxylase and spermidine/spermine N1-acetyltransferase activities in colonic epithelium, assayed as indicators of cell proliferation, were not significantly decreased as compared with control group values. Furthermore, vitamin D receptors in colonic epithelium were not significantly increased. Thus the present study indicates that OCT can exert inhibitory effects on tumor development in the small and large intestines, although the mechanism is unclear.

Acetyltransferases↗

PubMed1995

Prevalence of antibodies to Borrelia spirochetes among wild small rodents in central and western Japan.

Field rodents serve as a reservoir for Lyme disease spirochetes. To evaluate the antibody responses of rodents against different Borrelia species in relation to fauna of vector ticks feeding on them, we examined 272 sera of wild rodents, Apodemus speciosus, A. argenteus, and Eothenomys smithii, obtained in 27 locations in central and western Japan from 1981 to 1994. As to prevalences by rodent species using immunoperoxidase test, A. speciosus, A. argenteus and E. smithii showed 29.4%, 11.6% and 30.8% reactivity to Borrelia japonica, 10.7%, 7.2% and 3.8% to B. afzelii, 0.6%, 1.4% and 0% to B. garinii, and 14.7%, 7.2% and 11.5% to an unknown Borrelia species designated as It type, respectively. Each antibody to B. japonica, B. afzelii and B. sp. It type was detected widely both in central and western Japan, but the antibody to B. garinii was scarcely detectable in any area and rodent species examined. Apodemus mice in high mountain altitudes tend to have antibody to B. afzelii or B. japonica, and those in lower altitudes tend to have B. japonica or B. sp. It type. All 13 Apodemus mice from which B. japonica or B. sp. It type were isolated showed higher titers of antibodies to each homologous Borrelia species. The present results indicate that these antibody prevalences among rodents may be associated with dominant Ixodes ovatus and sporadic I. persulcatus on the mainland of Japan, and that Apodemus mice may not be an efficient reservoir for B. garinii. Such a serosurvey is a useful measure to evaluate the natural distribution of the pathogen.

Animals↗

PubMed1995

[Detection of Mycoplasma pneumoniae from throat swab by polymerase chain reaction].

Polymerase chain reaction (PCR) with primers directed against the 16S-rRNA gene of Mycoplasma pneumoniae was used to diagnose M. pneumoniae infections, and the results were compared with those of culture and serology methods. Eighty (22%) of 363 throat swab samples from patients with acute respiratory complaints gave positive results by using the PCR method. Sixty-seven (18.5%) of the samples were positive in culture method. Of 35 samples which were unreliable culture results due to contamination with other bacteria, 13 gave positive results in the PCR method. Of the 97 cases obtained throat swabs and paired sera, 28 (28.9%) showed positive results by the PCR assay, and 29 (29.9%) by serology method (particle agglutination test). The positive rate was increased to 36% by using both the PCR and the serology methods. From these results it was concluded that the PCR method is useful for laboratory diagnosis of M. pneumoniae infections.

Base Sequence↗

PubMed1995

Population sizes and growth pressure responses of intestinal microfloras of deep-sea fish retrieved from the abyssal zone.

The intestinal floras of seven deep-sea fish retrieved at depths of from 3,200 to 5,900 m were examined for population sizes and growth responses to pressure. Large populations of culturable bacteria, ranging from 1.1 x 10(sup6) to 3.6 x 10(sup8) cells per ml of contents, were detected when samples were incubated at conditions characteristic of those of the deep sea. Culturable cell counts at in situ pressures were greater than those at atmospheric pressure in all samples. Most of the strains isolated by the spread-plating method at atmospheric pressure later proved barophilic. Barophilic bacteria were the predominant inhabitants of the abyssal fish intestines.

Journal Article↗

PubMed1995

Identification of spirochetes isolated from wild rodents in Japan as Borrelia japonica.

Spirochetes isolated from three species of wild mice, Apodemus speciosus, Apodemus argenteus, and Eothenomys smithi, which were caught on Honshu, Japan, were characterized on the bases of protein profiles, reactivities with monoclonal antibodies (MAbs), and DNA homology values. All the isolates reacted with MAb O1441b, which is specific for Borrelia japonica, but not with MAb P62, which is specific for Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii. The DNA relatedness of four representatives isolates to strain HO14, a type strain of B. japonica, was 83 to 88%. From these findings, the spirochetes were identified as B. japonica.

Animals↗

PubMed1995

Giant cell glioblastoma in the frontal cortex of a dog.

A dark gray mass 3 cm in diameter replacing the right frontal cortex was found in the brain of a 5-year-old male Doberman Pinscher dog at necropsy. Microscopic studies revealed that the mass consisted of a proliferation of pleomorphic tumor cells: large bizarre or plump eosinophilic cells, multinucleated giant cells, and small lymphocytic cells. These neoplastic cells at the margin of the necrotic area had a psuedopalisade arrangement and tended to proliferate around blood vessels. Immunohistochemically, the tumor cells reacted intensely with the antibody for vimentin and moderately with those for S-100 and glial fibrillary acidic protein. This canine tumor is placed in the category of glioblastoma or undifferentiated astrocytoma, which is analogous to human giant cell glioblastoma.

Animals↗

PubMed1995

Stimulating effect of excess iron feeding on spontaneous lung tumor promotion in mice.

This study was undertaken to estimate if dietary iron could stimulate factors which promote spontaneous lung tumorigenesis in A/J mice, by measuring biochemical parameters of oxidative stress on pulmonary nuclei, ornithine decarboxylase (ODC) and spermidine/spermine N1-acetyltransferase (SAT) activities as markers of tumor promotion. Feeding excessive iron (500%) to A/J mice for 28 weeks significantly elevated pulmonary DNA single strand break (DNA-SSB) as well as nuclear thiobarbituric acid reactive substances (TBARS) in connection with the increase of nuclear nonheme iron level. In contrast, nuclear alpha-tocopherol levels in the iron-loaded group significantly decreased as compared to that in the control group. Pulmonary ODC and SAT activities showed increasing tendency on feeding excess iron for 28 weeks. These results suggest that dietary iron stimulates spontaneous lung tumor promotion in A/J mice, partly due to the enhancement of oxidative damage to the pulmonary nuclei.

Acetyltransferases↗

PubMed1995

[The porphyrias: it's definition, classification and differential diagnosis].

The porphyrias are diseases of enzyme deficiency in the heme synthetic pathway. They are classified into eight subtypes, two of which, ALADP and HEP, have been added as new subtypes during the past 10 years. These eight subtypes are divided into two groups, hepatic and erythropoietic. Hepatic porphyrias include AIP, ALADP, VP, HCP, PCT and HEP. Erythropoietic porphyrias consist of two subtypes, CP and EPP. From the clinical point of view, these subtypes may, also, be divided into acute and cutaneous porphyrias. AIP, ALADP, VP and HCP belong to acute porphyria. CP, EPP, PCT, and HEP to cutaneous porphyria. The diagnosis of porphyrias and differential diagnosis of subtypes are made by analyzing porphyrias and it's precursors in urine, blood and feces.

Diagnosis, Differential↗

PubMed1995

Enhancement of tobramycin binding to rat renal brush border membrane by vancomycin.

Effects of vancomycin (VCM) on tobramycin (TOB) binding to rat renal brush border membrane were examined by using isolated brush border membrane vesicles. The binding of TOB to the membrane vesicle was enhanced by the preincubation of the vesicle with VCM. The Scatchard analysis showed that this enhancement was due mainly to the increase in the number of binding sites. D-Glucose uptake was not affected by VCM, which suggests that the vesicles were not damaged by VCM. The binding of spermine, a typical polycationic compound, to the membrane vesicles also was increased by VCM treatment, and this also was because of the increase in the number of binding sites. These results suggested that the enhanced binding of these cationic compounds by VCM was due to the change in the negative charge on the membrane surface. Considering that the binding of aminoglycosides to brush border membranes is the initial step for the renal accumulation followed by the aminoglycosides-induced nephrotoxicity, this enhancement of TOB binding to the membrane by VCM may be one of the reasons for the enhanced TOB nephrotoxicity by VCM, which has often been reported in experimental animals and patients.

Animals↗

PubMed1995

[Surgical treatment for ischemic mitral regurgitation in patients with poor left ventricle].

Results of CABG with and without mitral valve surgery were analyzed retrospectively in 81 patients with ischemic mitral regurgitation (MR) to determine the effects of severity of MR and surgical treatment on survival. Seven of 81 patients had severe MR (more than Sellers III degrees/IV). Of these 7 patients, 5 patients underwent mitral valve replacement and 1 patient underwent mitral annuloplasty. Only one patient did not undergo valve surgery. This patient had slight improvement of the functional classification after CABG, but died of congestive heart failure 5 years after surgery. There were 3 hospital deaths and 5 late deaths in 81 patients. Among the 29 patients with poor left ventricle (EF < or = 0.3), there were 3 hospital deaths and 2 late deaths. Postoperatively, 12 patients had Sellers II degrees/IV or III degrees/IV MR. In 4 patients of these 12, the severity of MR was aggravated in comparison with the preoperative severity. Three of these 4 patients had perioperative myocardial infarction (PMI). IABP was utilized preoperatively in patients with poor left ventricle to keep the stable hemodynamics and prevent PMI. In these patients, there were no PMI, no hospital death, or no aggravation of MR. In conclusion, patients with Sellers I degree/IV or II degrees/IV MR require CABG only, whereas those with Sellers III degrees/IV or IV degrees/IV MR need CABG combined with mitral valve surgery. Preoperative use of IABP is useful for preventing PMI and aggravation of MR in patients with poor left ventricle.

Aged↗

PubMed1995

[Experience of modified Bentall's procedure for annulo-aortic ectasia].

To reduce the incidence of false aneurysm formation at the suture lines, a known complication with the inclusion technique such as Bentall's procedure or Cabrol's procedure, modified Bentall's procedure (Carrel patch technique), which is identical to Inberg's procedure, has been selected as treatment for annulo-aortic ectasia since 1991. This operation was carried out in 6 consecutive patients with annulo-aortic ectasia from July 1991 to August 1992. The aortic valve and the aneurysm were resected, the coronary ostia were dissected free, mobilized, and then implanted to the composite graft. It was necessary for one patient to undergo coronary artery bypass grafting for myocardial ischemia due to injury of the right coronary ostium. Thereafter, the button of coronary ostium was cut into a big size and then trimmed just before the implantation to the composite graft in order to prevent injury of the button of the coronary ostium. There was no hospital mortality. No pseudo-aneurysm at the coronary ostia or the distal aortic anastomosis was observed at control aortography carried out 1 month after surgery. One patient died 1 year after the first operation because of low cardiac output after the re-operation for pseudo-aneurysm at the proximal aortic anastomosis and infection of the composite graft. All the other patients have been symptom free during follow-up. The use of gelatin impregnated dacron graft and the reinforcement of the suture lines by Teflon felt strips minimized bleeding. One patient underwent this operation without blood transfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Vitamin E acts as a useful chemopreventive agent to reduce spontaneous lung tumorigenesis in mice.

The present study was designed to evaluate whether vitamin E could be a useful chemopreventive agent to reduce spontaneous lung tumorigenesis in mice. Starting at 6 weeks of age, groups were divided into three groups, i.e. A/J mice fed a control diet (A/J control), A/J mice fed a vitamin E-supplemented diet (A/J vitamin E) and ddY mice fed a control diet (ddY control). At the 28th experimental week, nuclear NADPH-driven active oxygen generation, thiobarbituric acid reactive substances (TBARS) and DNA single strand breaks (DNA-SSB) in A/J mice fed a control diet were significantly higher than those in the ddY control group. A/J mice fed Vitamin E for 28 weeks could decrease the levels of TBARS and DNA-SSB with a significant difference, as compared with those in A/J control mice. The nuclear alpha-tocopherol levels in A/J controls were significantly lower than those in ddY controls, on the contrary, the vitamin feeding to A/J mice increased nuclear alpha-tocopherol levels more than that in the ddY controls. At the 40th experimental week, lung tumor incidence and tumor multiplicity (percentage of mice with tumors) in A/J controls were reduced and brought close to those in ddY control mice by vitamin E. Then the alpha-tocopherol level in plasma of A/J controls was significantly lower than the level in plasma of ddY controls, and the level in tumor-bearing mice in A/J controls also showed a lower level with significant difference as compared to that in non-tumor-bearing mice of A/J controls. These results suggest that the difference in susceptibility to spontaneous lung tumorigenesis between A/J and ddY mice partly depends on the difference of oxidative stress on the pulmonary nuclei, and vitamin E can act as a useful chemopreventive agent to reduce spontaneous lung tumorigenesis in mice.

Animals↗