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Biomedical subjects

M Horiuchi

Publications and source records attributed to M Horiuchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

An autopsy case of hemilaterally dominant and systematic/extensive border zone infarction: sequela of preceding atherosclerotic obstruction of one common carotid artery followed by repeated episodes of systemic hypotension.

A 68-year-old man was admitted to St Marianna University Hospital on account of loss of consciousness with left hemiplegia. During the hospital recovery course with a rehabilitation procedure, the patient's blood pressure was very unstable, fluctuating between high (210/110 mmHg) and low (110/70 mmHg) values accompanied by a fainting sensation. A second stroke of left hemiplegia took place 1 month later. Afterwards, his condition worsened to tetraplegia with dysarthria. Three months later, lung cancer with multiple metastasis including his left neck was found and he died from adynamic ileus 6 months after the onset of the present illness. Autopsy revealed nearly complete atheromatous obstruction and more than 50% stenosis, respectively, of his right common and internal/external carotid arteries. His intracranial arterial trunks and main branches were all patent with localized atherosclerosis of only moderate degree. The pathology of the brain existed predominantly in the right hemisphere in the border zone area between the anterior and middle cerebral arteries systematically with numerous disseminated foci of complete or incomplete necrosis, white matter and gray matter being involved independently. Involvement of centrum semiovale white matter is more extensive and intensive than that of gray matter. Of the gray matter, cerebral cortex as well as striatum, periventricular (the third ventricle) gray and cerebellar cortex was involved. The specific characteristic topography and distribution of the lesions together with their histopathology are described in detail with illustration. It is concluded that this case represents an outstanding example of hemodynamic cerebral circulatory insufficiency doubly caused by hemilateral carotid artery stenosis and repeated episodes of systemic hypotension.

Aged↗
PubMed2001

Infection of human lung fibroblasts with Epstein-Barr virus causes increased IL-1beta and bFGF production.

An association between Epstein-Barr virus (EBV) infection and fibroblast proliferation in the interstitial spaces of the lung has been suggested in idiopathic interstitial pneumonia. In this study we show that EBV can infect human lung fibroblasts in vitro. A primary-cultured human lung fibroblast cell line, designated CCD-32Lu, expressed EBV nuclear antigen 1 after coculture with lethally irradiated EBV producing cells. The infection further induced CCD-32Lu cells to produce the fibrogenic cytokines basic fibroblast growth factor (bFGF) and interleukin-1beta. These findings indicate that lung fibroblasts may be a target for EBV infection and suggest that EBV may play a role in increased production of these cytokines and induce fibroblast proliferation in idiopathic interstitial pneumonia.

Antibodies, Blocking↗
PubMed2001

Angiotensin converting enzyme inhibitor restrains inflammation-induced vascular injury in mice.

OBJECTIVES: Recent advances in molecular genetics made the mouse model important for studying the genetic basis of hypertension and vascular diseases such as the components of the renin-angiotensin system. This study was undertaken to investigate the role of angiotensin converting enzyme (ACE) in the mouse vascular injury model. DESIGN AND METHODS: Inflammation-induced vascular injury was created by placing a polyethylene cuff around the femoral artery of 12-14-week-old male FVB/N mice. Cuffed arteries were harvested and applied to reverse transcriptase-polymerase chain reaction analysis and immunohistochemistry for ACE. Subsequently, the effects of an ACE inhibitor, perindopril (3 mg/kg per day), on neointimal thickening were examined 2 weeks after cuff placement The influence of a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg per day) on the effects of perindopril was also examined. RESULTS: ACE mRNA expression increased in a time-dependent manner up to 2 weeks after cuff placement. Immunoreactive ACE was localized in the endothelium in the intact artery, while positive staining was observed in the medial and neointimal layer as well as in the periadventitial region of the cuffed artery. The intimamedia area ratio was significantly decreased by perindopril treatment (vehicle, 0.75+/-0.10; perindopril, 0.32+/-0.04; P< 0.05). The effect of perindopril was abrogated by coadministration of L-NAME whereas L-NAME alone did not affect the intima-media ratio (L-NAME, 0.66+/-0.11; perindopril + L-NAME, 0.72+/-0.09). CONCLUSIONS: This study provides evidence that ACE plays a role in cuff-induced neointimal thickening in mice. Nitric oxide may contribute, at least in part, to the inhibitory effects of perindopril.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Inhibition of TNF-alpha, induced cytokine and adhesion molecule. Expression in glomerular cells in vitro and in vivo by transcription factor decoy for NFkappaB.

Activation of certain cytokines and adhesion molecules has been postulated being involved in the pathogenesis of experimental and human glomerulonephritis. In this study, we examined whether the transcription factor, nuclear factor kappaB (NFkappaB), mediated the expression of these genes involved with the inflammatory response of mesangial cells by using transcription factor decoy oligodeoxynucleotides (ODN) to block NFkappaB binding to the promoter site of its target genes. We hypothesized that the NFkappaB decoy ODN can inhibit the coordinated activation of cytokines and adhesion molecules induced by TNF-alpha. Increased binding activity of NFkappaB induced by TNF-alpha was effectively blocked by the NFkappaB decoy ODN. TNF-alpha stimulated CAT expression, which was significantly inhibited by transfection of NFkappaB, but not by scrambled decoy ODN. Of importance, NFkappaB, but not scrambled decoy ODN, significantly attenuated the increase in RNA and protein levels of IL-1alpha, IL-1beta, IL-6, ICAM-1 and VCAM-1 induced by TNF-alpha assessed by RT-PCR. Moreover, in vivo transfection of NFkappaB decoy ODN inhibited expressions of these cytokines and adhesion molecules induced by TNF-alpha injection. These results suggest a novel therapeutic strategy for the treatment of glomerulonephritis using decoy ODN to block the binding of NFkappaB, inhibiting the coordinated transactivation of the key cytokines and adhesion molecules, and thereby suppressing the inflammatory process.

Animals↗
PubMed2001

Mitogenic and antiapoptotic actions of hepatocyte growth factor through ERK, STAT3, and AKT in endothelial cells.

Hepatocyte growth factor (HGF), a member of the angiogenic growth factors, may play a pivotal role in the regulation of endothelial cells, inasmuch as HGF shows mitogenic and antiapoptotic actions in endothelial cells. Because the mechanism of these actions is still unclear, we examined the signal transduction system of HGF in human aortic endothelial cells. Treatment of endothelial cells with recombinant HGF (rHGF) resulted in a significant increase in DNA synthesis as assessed by thymidine incorporation. Importantly, phosphorylation of extracellular signal-related kinase (ERK) and Akt by rHGF was clearly observed. Thus, we further examined the effects of specific inhibitors of ERK or Akt on cell proliferation. Pretreatment with PD98059, a mitogen-activated protein kinase kinase inhibitor, significantly attenuated cell proliferation induced by rHGF, whereas inhibitors of phosphatidylinositol-3-OH kinase, wortmannin, and LY-294002, did not. Interestingly, treatment with rHGF significantly increased the phosphorylation of the signal transducers and activators of transcription (STAT)3 (Ser727), whereas PD98059 attenuated the phosphorylation of Ser727 induced by rHGF. In addition, treatment with rHGF significantly increased the promoter activity of c-fos, which includes the sis-inducible element and serum response element, whereas PD98059 completely attenuated the activation of the c-fos promoter induced by rHGF. In contrast, inhibition of Akt by wortmannin and LY-294002 failed to inhibit the phosphorylation of STAT3 and c-fos activation. On the other hand, treatment with rHGF attenuated the increase in LDH release and caspase-3 activity induced by tumor necrosis factor-alpha stimulation. In contrast to DNA synthesis, wortmannin and LY-294002 markedly attenuated the decrease in caspase-3 activity mediated by rHGF, whereas PD98059 did not. Overall, the present study demonstrated that HGF stimulated cell proliferation through the ERK-STAT3 (Ser727) pathway and had an antiapoptotic action through the phosphatidylinositol-3-OH kinase-Akt pathway in human aortic endothelial cells. These findings provide new perspectives in the role of HGF in cardiovascular disease.

Androstadienes↗
PubMed2001

Angiotensin II type 2 receptor inhibits epidermal growth factor receptor transactivation by increasing association of SHP-1 tyrosine phosphatase.

Angiotensin (Ang) II has 2 major receptor isoforms, Ang type 1 (AT(1)) and Ang type (AT(2)). AT(1) transphosphorylates epidermal growth factor receptor (EGFR) to activate extracellular signal-regulated kinase (ERK). Although AT(2) was shown to inactivate ERK, the action of AT(2) on EGFR activation remains undefined. Using AT(2)-overexpressing vascular smooth muscle cells from AT(2) transgenic mice, we studied these undefined actions of AT(2). Maximal ERK activity induced by Ang II was increased 1.9- and 2.2-fold by AT(2) inhibition, which was abolished by orthovanadate but not okadaic acid or pertussis toxin. AT(2) inhibited AT(1)-mediated EGFR tyrosine phosphorylation by 63%. The activity of SHP-1 tyrosine phosphatase was significantly upregulated 1 minute after AT(2) stimulation and association of SHP-1 with EGFR was increased, whereas AT(2) failed to tyrosine phosphorylate SHP-1. Stable overexpression of SHP-1-dominant negative mutant completely abolished AT(2)-mediated inhibition of EGFR and ERK activation. AT(1)-mediated c-fos mRNA accumulation was attenuated by 48% by AT(2) stimulation. Induction of fibronectin gene containing an AP-1 responsive element in its 5'-flanking region was decreased by 37% after AT(2) stimulation, corresponding to the results of gel mobility assay with the AP-1 sequence of fibronectin as a probe. These findings suggested that AT(2) inhibits ERK activity by inducing SHP-1 activity, leading to decreases in AP-1 activity and AP-1-regulated gene expression, in which EGFR dephosphorylation plays an important role via association of SHP-1.

Angiotensin II↗
PubMed2001

Involvement of bradykinin and nitric oxide in leptin-mediated glucose uptake in skeletal muscle.

Regulation of glucose metabolism in peripheral tissues by leptin has been highlighted recently, although its mechanism is unclear. In this study, we postulated that bradykinin and nitric oxide (NO) are involved in the effect of leptin-mediated glucose uptake in peripheral tissues and examined these possibilities. Injection of leptin (200 pg/mouse) into the ventromedial hypothalamus-enhanced glucose uptake in skeletal muscle and brown adipose tissue, but not in white adipose tissue. Treatment with Hoe140 (0.1 mg/kg), bradykinin B2 receptor antagonist, or L-NAME (N:(G)-nitro-L-arginine methyl ester) (30 mg/kg), nitric oxide synthase inhibitor, did not influence the basal level of glucose uptake in skeletal muscle and the adipose tissue, whereas Hoe140 and L-NAME inhibited leptin-mediated glucose uptake in skeletal muscles, but had no effect in adipose tissue. However, Hoe140 and L-NAME did not inhibit insulin (1.0 U/kg)-mediated glucose uptake in all tissues examined. Taken together, these results suggest that leptin enhances bradykinin and/or the NO system, which contributes at least partially to the enhanced glucose uptake in skeletal muscles.

Animals↗
PubMed2001

Glycidol degrades scrapie mouse prion protein.

Agents of transmissible spongiform encephalopathy (prion) are known to be extremely resistant to physicochemical inactivation procedures such as heat, radiation, chemical disinfectants such as detergents, alcohols, glutaraldehyde, formalin, and so on. Because of its remarkable resistance, it is difficult to inactivate prion. Chemical inactivation seems to be a practical method because it is applicable to large or fixed surfaces and complicated equipment. Here, three epoxides: beta-propiolactone, propylene oxide, and glycidol (GLD) were examined of their inactivation ability against scrapie-mouse prion protein (PrP(Sc)) under various conditions of chemical concentration, incubation time, and temperature. Among these chemicals, GLD worked most effectively and degraded PrP into small fragments. As a result of the bioassay, treatment with 3% GLD for 5 hr and 5% GLD for 2, 5 hr or 12 hr at room temperature prolonged the mean incubation time by 44, 30, 110 and 73 days, respectively. From dose-incubation time standard curve, the decrease in infectivity titers were estimated as 10(3) or more. Therefore, degradation of PrP(Sc) by GLD decreased the scrapie infectivity. It is also suggested that pH and salt concentrations influence the effect of GLD. Although further study is necessary to determine the optimal condition, GLD may be a potential prion disinfectant.

Animals↗
PubMed2001

[A case of elderly onset Parkinson's disease complicated by dropped head syndrome].

An 86-year old man presented with a 7-year history of gait disturbance. He was admitted to our hospital on April 2000 because he was experiencing difficulty eating due to progression of dropped head syndrome. Upon standing and sitting, remarkable dropped head and kyphosis were observed. When lying, the patient was able to stretch his neck, and he could stand and walk with the aid of a walker. Rigidity and resting tremor were present predominantly in the lower limbs. Parkinson's disease was diagnosed therefore L-dopa and Cabergoline were administered. Parkinsonism and dropped head syndrome improved in response to treatment. Cases involving dropped head syndrome due to Parkinson's disease are reportedly improved by L-dopa, but exasperated by dopamine agonists. The mechanism of dropped head is thought to be an imbalance in the tonus of the anterior and posterior neck muscles. Dropped head in the present case may have been a complication of Parkinson's disease since it improved in response to L-dopa.

Aged↗
PubMed2001

An adult case of congenital external carotid-jugular arteriovenous fistula with reversible circulatory insufficiency in the cerebellum and lower brain stem.

A 27-year-old man with congenital external carotid-jugular arteriovenous fistula presented with a diminished level of consciousness and an ataxic gait. Axial fluid-attenuated inversion-recovery (FLAIR) MR imaging revealed venous congestion, a dilated right jugular vein, and an area of high signal intensity in the brain stem and cerebellum. Angiography showed a dilated right external carotid artery and jugular vein and the presence of a fistula. After coil embolization of the fistula, axial MR FLAIR images showed only a few areas of high signal intensity in the brain stem and cerebellum. The causal factor was venous congestion in the inferior petrosal sinus and basilar plexus due to high blood pressure in the jugular vein. This case is presented for its unusual clinical and radiologic findings.

Adult↗
PubMed2001

[Follicular bronchiolitis associated with pulmonary tuberculosis--report of a case].

The patient, a 39-year-old man, presented in May 1997 with an untreated persistent cough with excessive sputum of 5 years' duration. He was admitted to hospital because of the severity of the symptoms and the presence of acid-fast bacilli in his sputum. These bacilli were identified as Mycobacterium tuberculosis by the polymerase chain reaction method. After treatment with antituberculous drugs was initiated, his symptoms and the patchy infiltrative shadows on his chest radiographs gradually resolved. However, the patient continued to expectorate a purulent sputum, showed diffuse micronodular shadows on chest radiographs, and had hypoxemia as well as mixed ventilatory and small airway disturbances on pulmonary function tests. We performed a video-assisted thoracoscopic biopsy of the lung, which revealed follicular bronchiolitis.

Adult↗
PubMed2001

[The new portable system for home enteral nutrition, Portermate, made a patient possible go out for a long time: report of a case].

The patient, who is received home enteral nutrition (HEN) for a long time in a day, has problems on moving all days. Now, we tried Portermate, which is new portable devices for HEN, in his clinical care. The patient is chronic pancreatitis, and his clinical problems becomes to be worse after he ate. He was under total enteral nutrition via jejunostomy. His clinical complications were almost controlled after HEN, but he has a few complains receiving enteral nutrition. He would not move easily, for an old HEN system was not compact to move. Portermate made him go everywhere he wanted any time. It extremely improved his QOL under HEN. He continues to use Portermate.

Activities of Daily Living↗
PubMed2000

ATRAP, novel AT1 receptor associated protein, enhances internalization of AT1 receptor and inhibits vascular smooth muscle cell growth.

We have identified a novel, membrane-located protein that interacts specifically with the carboxyl-terminal cytoplasmic domain of the AT1a receptor, which we named ATRAP (for AT1 receptor-associated protein). To further investigate the role of ATRAP in AT1 receptor function, we examined the effect of overexpression of ATRAP on angiotensin II (Ang II)-induced AT1 receptor desensitization and/or internalization, and cell proliferation in adult vascular smooth muscle cells (VSMCs). Transfection of ATRAP potentiated AT1 receptor internalization upon Ang II stimulation in these VSMCs. Moreover, we observed that AT1 receptor-induced DNA synthesis was markedly inhibited in ATRAP transfected VSMCs associated with the inhibition of the phosphorylation of signal transducers and activators of transcription (STAT) 3 and Akt. Our results suggest that ATRAP functions as a negative regulator in AT1 receptor-mediated cell proliferation in VSMCs.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Molecular mechanism of fibronectin gene activation by cyclic stretch in vascular smooth muscle cells.

Fibronectin plays an important role in vascular remodeling. A functional interaction between mechanical stimuli and locally produced vasoactive agents is suggested to be crucial for vascular remodeling. We examined the effect of mechanical stretch on fibronectin gene expression in vascular smooth muscle cells and the role of vascular angiotensin II in the regulation of the fibronectin gene in response to stretch. Cyclic stretch induced an increase in vascular fibronectin mRNA levels that was inhibited by actinomycin D and CV11974, an angiotensin II type 1 receptor antagonist; cycloheximide and PD123319, an angiotensin II type 2 receptor antagonist, did not affect the induction. In transfection experiments, fibronectin promoter activity was stimulated by stretch and inhibited by CV11974 but not by PD123319. DNA-protein binding experiments revealed that cyclic stretch enhanced nuclear binding to the AP-1 site, which was partially supershifted by antibody to c-Jun. Site-directed mutation of the AP-1 site significantly decreased the cyclic stretch-mediated activation of fibronectin promoter. Furthermore, antisense c-jun oligonucleotides decreased the stretch-induced stimulation of the fibronectin promoter activity and the mRNA expression. These results suggest that cyclic stretch stimulates vascular fibronectin gene expression mainly via the activation of AP-1 through the angiotensin II type 1 receptor.

Angiotensin II↗
PubMed2000

Inhibitory effect of angiotensin II type 2 receptor on coronary arterial remodeling after aortic banding in mice.

BACKGROUND: The renin-angiotensin system is thought to be critical for the development of cardiac hypertrophy, whereas the role of the angiotensin II type 2 (AT(2)) receptor in the process is not defined. Using the AT(2) receptor-null (Agtr2-) mouse, we tested the hypothesis that the AT(2) receptor could exert an antigrowth effect in cardiac hypertrophy. METHODS AND RESULTS: Cardiac hypertrophy was induced by suprarenal abdominal aortic banding in 10- to 12-week-old Agtr2- and wild-type (Agtr2+) mice for 6 or 12 weeks. Carotid arterial pressure was not different between the strains, although aortic banding increased arterial pressure by approximately 40 mm Hg. Aortic banding increased the heart-weight/body-weight ratio and the cross-sectional area of cardiomyocytes by 15%, resulting in comparable cardiomyocyte hypertrophy in the 2 strains. In contrast, coronary arterial thickening and perivascular fibrosis, determined by the media/lumen-area ratio and the collagen/vessel-area ratio, respectively, were 50% greater in Agtr2- than in Agtr2+ mice after banding, whereas these parameters were similar in sham-operated mice. Radioligand binding studies using the whole heart and immunohistochemistry showed that AT(2) receptor expression was limited and localized in the coronary artery and perivascular region. CONCLUSIONS: These results suggest that the AT(2) receptor mediates an inhibitory effect on coronary arterial remodeling, such as medial hypertrophy and perivascular fibrosis in response to pressure overload, and an activation of the renin-angiotensin system.

Animals↗
PubMed2000

Ulip6, a novel unc-33 and dihydropyrimidinase related protein highly expressed in developing rat brain.

Here, we report the identification of Ulip6, a novel unc-33 and dihydropyrimidinase related protein that belongs to the Ulip/CRMP protein family. Ulip6 was found in a yeast two-hybrid screen using the neuronal glycine transporter GlyT2 as bait. The rat and human Ulip6 sequences are highly homologous and most closely related to the liver enzyme dihydropyrimidinase (Ulip5). Northern and Western analysis of rat tissues revealed that the distribution of the Ulip6 mRNA and protein resembles those of brain-type Ulip proteins. Like Ulip1-4, Ulip6 is highly expressed in embryonic and early postnatal brain and spinal cord. These findings are consistent with Ulip6 having a function in neuronal differentiation and/or axon growth.

Amidohydrolases↗
PubMed2000

LXRalpha functions as a cAMP-responsive transcriptional regulator of gene expression.

LXRalpha is a member of a nuclear receptor superfamily that regulates transcription. LXRalpha forms a heterodimer with RXRalpha, another member of this family, to regulate the expression of cholesterol 7alpha-hydroxylase by means of binding to the DR4-type cis-element. Here, we describe a function for LXRalpha as a cAMP-responsive regulator of renin and c-myc gene transcriptions by the interaction with a specific cis-acting DNA element, CNRE (an overlapping cAMP response element and a negative response element). Our previous studies showed that renin gene expression is regulated by cAMP, at least partly, through the CNRE sequence in its 5'-flanking region. This sequence is also found in c-myc and several other genes. Based on our cloning results using the yeast one-hybrid system, we discovered that the mouse homologue of human LXRalpha binds to the CNRE and demonstrated that it binds as a monomer. To define the function of LXRalpha on gene expression, we transfected the renin-producing renal As4.1 cells with LXRalpha expression plasmid. Overexpression of LXRalpha in As4.1 cells confers cAMP inducibility to reporter constructs containing the renin CNRE. After stable transfection of LXRalpha, As4.1 cells show a cAMP-inducible up-regulation of renin mRNA expression. In parallel experiments, we demonstrated that LXRalpha can also bind to the homologous CNRE in the c-myc promoter. cAMP promotes transcription through c-myc/CNRE:LXRalpha interaction in LXRalpha transiently transfected cells and increases c-myc mRNA expression in stably transfected cells. Identification of LXRalpha as a cAMP-responsive nuclear modulator of renin and c-myc expression not only has cardiovascular significance but may have generalized implication in the regulation of gene transcription.

Animals↗