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Biomedical subjects

K Hashimoto

Publications and source records attributed to K Hashimoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

Hypoxia response element of the human vascular endothelial growth factor gene mediates transcriptional regulation by nitric oxide: control of hypoxia-inducible factor-1 activity by nitric oxide.

Nitric oxide (NO) regulates production of vascular endothelial growth factor (VEGF) by normal and transformed cells. We demonstrate that NO donors may up-regulate the activity of the human VEGF promoter in normoxic human glioblastoma and hepatoma cells independent of a cyclic guanosine monophosphate-mediated pathway. Deletion and mutation analysis of the VEGF promoter indicates that the NO-responsive cis-elements are the hypoxia-inducible factor-1 (HIF-1) binding site and an adjacent ancillary sequence that is located immediately downstream within the hypoxia-response element (HRE). This work demonstrates that the HRE of this promoter is the primary target of NO. In addition, VEGF gene regulation by NO, as well as by hypoxia, is potentiated by the AP-1 element of the gene. Our study also reveals that NO and hypoxia induce an increase in HIF-1 binding activity and HIF-1alpha protein levels, both in the nucleus and the whole cell. These results suggest that there are common features of the NO and hypoxic pathways of VEGF induction, while in part, NO mediates gene transcription by a mechanism distinct from hypoxia. This is demonstrated by a difference in sensitivity to guanylate cyclase inhibitors and a different pattern of HIF-1 binding. These results show that there is a primary role for NO in the control of VEGF synthesis and in cell adaptations to hypoxia. (Blood. 2000;95:189-197)

Base Sequence↗
PubMed2000

Measurement of adenylate cyclase activity in the right ventricular endomyocardial biopsy samples from patients with chronic congestive heart failure.

A highly sensitive fluorometric assay technique was adopted in order to examine the adenylate cyclase activity in the minute right ventricular endomyocardial biopsy samples from patients with chronic congestive heart failure (n = 10). Norepinephrine (10(-4) M) and adenosine (10(-3) M) were incubated for 30 min with 10 microl of membrane preparation (1-2 mg protein/mg) to analyze the extent of the receptor-coupled adenylate cyclase activity. Forskolin (10(-4) M) stimulation was used to estimate the maximum adenylate cyclase activity (pmol/mg protein/min, mean +/- SE). The new microanalytical cyclic AMP assay involves four steps: enzymatic destruction of noncyclic adenine nucleotides and phosphorylated metabolites, conversion of cyclic AMP to ATP, amplification of ATP by enzymatic cycling, and fluorometric measurement of NADPH, which is generated in proportion to initial cyclic AMP levels. Basal and forskolin-stimulated maximum adenylate cyclase activities were 75 +/- 8 and 123 +/- 15, respectively. Norepinephrine increased the adenylate cyclase activity to 107 +/- 14, while adenosine tended to decrease it to 65 +/- 7. In addition, elimination of adenosine by adenosine deaminase (10 U/ml) slightly increased the adenylate cyclase activity to 82 +/- 9. These results indicate that the adenylate cyclase activity can be measured in minute endomyocardial biopsy samples. Use of this new approach shows promise of becoming a new and potentially important way to predict the efficacy of pharmacological treatment.

Adenosine↗
PubMed2000

Characteristics of myocardial 18F-fluorodeoxyglucose positron emission computed tomography in dilated cardiomyopathy and ischemic cardiomyopathy.

Myocardial 18F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has been used to assess myocardial ischemia and viability, but few studies have conducted on FDG-PET for dilated cardiomyopathy (DCM). We investigated myocardial FDG uptake in patients with DCM in comparison with ischemic cardiomyopathy (ICM). Twenty-four patients with heart failure were included in this study. Fourteen of them were diagnosed as DCM and the other 10 were ICM. All of them underwent myocardial FDG-PET at fasting and after glucose loading the same day. FDG uptake was quantified by the ratio of the counts at the heart to those at the liver (H/L ratio). Left ventricular (LV) function was measured by echocardiography. We classified FDG distribution patterns in the myocardium in the fasting state into 3 types (faint uptake, regional uptake and diffuse uptake). In DCM patients, 5 had faint uptake, 7 had regional uptake, and the other 2 had diffuse uptake. On the other hand, all ICM patient had regional uptake (p < 0.05). In DCM, there were no significant relationships between the patterns and LV functions. On the other hand, there were close correlation between the H/L ratio after glucose loading and the left ventricular ejection fraction (r = 0.680, p < 0.01). The changes in PET images caused by glucose loading were classified into 2 types (non-reversing and reversing patterns). DCM significantly showed a non-reversing pattern (86%, 12 of 14 patients) whereas ICM showed mainly a reversing pattern (70%, 7 of 10 patients; p < 0.05). In conclusion, myocardial FDG uptake after glucose loading may indicate a myocardial viable mass although FDG uptake at fasting was not evidently related to LV function. The change in the pattern of the FDG image from fasting to glucose loading may be useful in differentiating DCM from ICM.

Adult↗
PubMed2000

Pulmonary atresia with intact ventricular septum, antegrade coronary-right ventricular sinusoidal communication, and Wolff-Parkinson-White syndrome.

A fenestrated Fontan operation was performed successfully in a patient with pulmonary atresia with intact ventricular septum, an antegrade sinusoidal communication, and Wolff-Parkinson-White syndrome. Unlike most cases, blood flow in the sinusoidal communication was antegrade, from the left anterior descending artery to the right ventricle. This is the first report of the combination of pulmonary atresia with intact ventricular septum and Wolff-Parkinson-White syndrome.

Child, Preschool↗
PubMed2000

Frequency-dependent changes in calcium cycling and contractile activation in SERCA2a transgenic mice.

OBJECTIVE: This study was undertaken to investigate the mechanism of altered contractility in hearts from transgenic mice overexpressing the sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA2a). In particular, we sought to determine whether the reported increase in contractility is frequency-dependent, as might be expected if attributable to changes in SR Ca2+ loading. METHODS: Intracellular [Ca2+] and contractile force were measured at room temperature (22 degrees C) simultaneously in fura-2-loaded isometrically-contracting trabeculae dissected from the hearts of FVB/N control (n = 6) or SERCA2a transgenic (n = 6) mice. RESULTS: SERCA transgenics exhibit a positive force-frequency relationship, but this was flat in age- and strain-matched controls. SERCA transgenics exhibit a sizable increase in calcium transient amplitude relative to controls, with a concomitant increase in force generation at higher frequencies of stimulation. Amplitudes of Ca2+ transients (transgenics: 1.56 +/- 0.09 micromol/L, controls: 1.21 +/- 0.14) and twitches (transgenics: 21.71 +/- 0.91 mN/mm2, controls: 13.74 +/- 1.67) were significantly different at 2.0 Hz stimulation (P < 0.05). CONCLUSION: An increase in SERCA expression increases the ability of the sarcoplasmic reticulum to store calcium, such that more calcium is available to be released during each heartbeat at higher stimulation rates.

Animals↗
PubMed2000

Ebselen decreases ozone-induced pulmonary inflammation in rats.

We studied the effects of ebselen on rat lung inflammatory responses against ozone exposure. Rats were treated with ebselen every 12 h from 1 h before a single 4-h exposure to 2 ppm ozone. Treatment with ebselen (10 mg/kg) significantly decreased pulmonary inflammation as indicated by the albumin concentration and the number of neutrophils in the bronchoalveolar lavage fluid 18 h after the ozone exposure. Although treatment with ebselen did not alter the macrophage expression of inducible nitric oxide synthase after the ozone exposure, it did markedly inhibit the nitration reaction of tyrosine residues, suggesting that ebselen scavenges peroxynitrite during ozone-induced pulmonary inflammation. Treatment with ebselen also enhanced the pulmonary expression of both copper, zinc, and manganous superoxide dismutases at the same time point. These enzymes may also contribute to a decrease in the formation of peroxynitrite by lowering the concentration of superoxide. Thus, ebselen represents a useful compound for protecting against certain acute lung injuries by modulating the oxidant-related inflammatory process.

Acute Disease↗
PubMed2000

Effect of liver transplantation in a twin for biliary atresia on physical development and intellectual performance: report of a case.

A case of twins, one of whom suffered from biliary atresia, is described herein. Although the patient had been doing well until 11 years of age after previously undergoing a primary hepatic portoenterostomy, she had to then undergo a liver transplantation due to severe refractory cholangitis at 14 years of age. Although the patient's intellectual performance had severely declined due to the progression of her illness for several years, it completely recovered after the liver transplantation. In cases where the physical development in childhood has been well preserved, liver transplantation might therefore offer the chance for a full recovery of deteriorated intellectual performance.

Biliary Atresia↗
PubMed2000

Multiple inflammatory pseudotumors mimicking liver metastasis from colon cancer: report of a case.

A 54-year-old man underwent an operation for colon cancer histologically diagnosed as moderately differentiated adenocarcinoma with clinical staging of Dukes C. He was prescribed carmofur for adjuvant chemotherapy. A follow-up computed tomography scan done 6 months later revealed two new low-density areas in the liver. A diagnosis of metastatic adenocarcinoma from the previous colon cancer was presumed, based on the patient's history and radiological findings, and resection of the affected area of liver was performed. Histological examination of these tumors revealed that they were inflammatory pseudotumors (IPT). The patient had an excellent postoperative course and has shown no further signs of recurrence in the 3 years since his last operation. IPT of the liver is a rare disease, for which no methods of diagnosis and treatment have been established, since it is difficult to distinguish IPT from hepatocellular carcinoma or metastatic carcinoma. We describe this case with a review of the 101 cases of IPT documented in the Japanese literature, in the hope that it will contribute to the diagnosis and treatment of this unusual disease entity.

Adenocarcinoma↗
PubMed2000

Sequence analysis, gene expression, and chromosomal assignment of mouse Borg4 gene and its human orthologue.

The Borg (binder of Rho GTPases) family proteins interact with CDC42 and TC10 in a guanosine triphosphate (GTP)-dependent manner. We have isolated a full-length cDNA of the mouse Borg4 gene, which is a member of this family. Sequence analysis revealed that this gene encoded a putative 349-amino acid protein. By reverse transcription--coupled polymerase chain reaction (RT-PCR) analysis, we observed that Borg4 was expressed ubiquitously in adult tissues. Additionally, we determined the entire cDNA sequence of the putative human Borg4 orthologue. By fluorescence in situ hybridization, mouse Borg4 and the putative human orthologue have been assigned to mouse chromosome 11E and human chromosome 17q24-25, which has been described as syntenic to the mouse region.

Adaptor Proteins, Signal Transducing↗
PubMed2000

A novel interstitial deletion of KAL1 in a Japanese family with Kallmann syndrome.

We identified a novel interstitial deletion that spanned from exons 5 to 10 of KAL1 in two Japanese brothers with X-linked Kallmann syndrome (KS; MIM no. 308700). Both brothers had hypogonadism, unilateral renal agenesis, and disturbance of the sense of smell, but they had no other neurological manifestations, including mental disturbance. Their mother was confirmed to be an asymptomatic carrier, by use of a comparative multiplex polymerase chain reaction (PCR) analysis. The present patients are further examples of patients with KS without mental disturbance caused by a mutation confined to KAL1.

Adult↗
PubMed2000

Sphingosine 1-phosphate induces sinus tachycardia and coronary vasoconstriction in the canine heart.

OBJECTIVE: Sphingosine 1-phosphate is a naturally occurring biologically active lysophospholipid. Recent studies suggested that sphingosine 1-phosphate is released into the blood flow from activated platelets upon stimulation to exert multiple biological phenomenon. The purpose of this study was to assess the effects of sphingosine 1-phosphate on sinus automaticity, ventricular contraction and coronary blood flow. METHODS: The canine isolated, blood-perfused sinoatrial node and papillary muscle preparations were used. RESULTS: Sphingosine 1-phosphate increased the sinoatrial rate, while it decreased the coronary blood flow, which was followed by a weak negative inotropic effect. These positive chronotropic and coronary vasoconstrictor effects were not attenuated by the beta- and alpha-adrenoceptor antagonists atenolol and prazosin, respectively. Furthermore, sphingosine 1-phosphate did not affect the adenylate cyclase activity of the membrane preparations made from the canine right atrium and right ventricle, indicating the involvement of a novel signaling pathway in sphingosine 1-phosphate-induced cardiac effects. CONCLUSIONS: These results may provide a clue to better understanding the physiological as well as the pathophysiological regulation of sphingosine 1-phosphate in the heart.

Adenylyl Cyclases↗
PubMed2000

A polymorphism upstream from the human paraoxonase (PON1) gene and its association with PON1 expression.

Human serum paraoxonase (PON1) is an esterase that has been shown to decrease the susceptibility of lipoproteins to lipid peroxidation. We found a polymorphism of cytosine/thymidine (-108C/T, the number is from the ATG codon) in the upstream region of the PON1 gene. The luciferase activity was lower in the -108T allele than in the -108C allele. The serum PON1 concentrations in 132 normal subjects were as follows: -108CC>-108CT and>-108TT genotypes. The polymorphism upstream from the PON1 gene is associated with transcription of the PON1 gene and the serum PON1 concentration.

Alleles↗
PubMed2000

Significantly high regional morbidity of MPO-ANCA-related angitis and/or nephritis with respiratory tract involvement after the 1995 great earthquake in Kobe (Japan).

Within a 3-year period after the Great Earthquake of Kobe (Japan) resulted in more than 6,000 deaths and complete destruction of the central area of Kobe City, 14 patients (group 1 [G1]) with myeloperoxidase (MPO)-antineutrophil cytoplasmic autoantibody (ANCA)-related angitis and/or nephritis presented to Nishi-Kobe Medical Center in western Kobe City. On the other hand, only 15 patients with this disease were encountered between 1990 and 1997 at Kyoto University Hospital in Kyoto City, which is located 80 km from Kobe City and was only minimally affected by the earthquake. These 15 patients and 1 patient who presented to Nishi-Kobe Medical Center before the Great Earthquake were classified as group 2 (G2). Although the average MPO-ANCA titer in G1 was almost the same as that in G2, G1 showed a significantly greater average value for white blood cells than G2 (11,321 +/- 4,369 versus 8,116 +/- 2, 389/microL; P < 0.05). Concerning renal function, a significant elevation in creatinine (Cr) levels at diagnosis (7.4 +/- 3.8 versus 2.1 +/- 1.4 mg/dL; P < 0.01) and rapidly declining rates of reciprocal Cr levels were noted in G1 (0.325 +/- 0.304 versus 0.087 +/- 0.069 dL/mg. wk; P < 0.01). The number of patients who required emergency hemodialysis was significantly greater in G1 than G2 (nine versus three patients; P < 0.02); however, the incidence of renal death and mortality were not significantly different between the groups. The number of patients who reported upper respiratory tract inflammation as an initial symptom was also significantly greater in G1 than G2 (eight versus two patients; P < 0.01). Moreover, patients in G1 experienced a significantly greater rate of severe pulmonary involvement during the hospital course than G2 (pulmonary hemorrhage, five versus no patients; interstitial pneumonitis, four versus two patients, respectively; P < 0.01). The relatively uniform and distinctive clinical features of the disease after the Great Earthquake, in conjunction with a high morbidity, suggest a relationship between disease development and this urban type of earthquake. Severely provoking air pollution caused by massive destruction and reconstruction of the city may have caused high frequencies of upper respiratory tract inflammation as an initial symptom and severe pulmonary involvement.

Aged↗
PubMed2000

Local calcium release in dendritic spines required for long-term synaptic depression.

We have used rats and mice with mutations in myosin-Va to evaluate the range and function of IP3-mediated Ca2+ signaling in dendritic spines. In these mutants, the endoplasmic reticulum and its attendant IP3 receptors do not enter the postsynaptic spines of parallel fiber synapses on cerebellar Purkinje cells. Long-term synaptic depression (LTD) is absent at the parallel fiber synapses of the mutants, even though the structure and function of these synapses otherwise appear normal. This loss of LTD is associated with selective changes in IP3-mediated Ca2+ signaling in spines and can be rescued by photolysis of a caged Ca2+ compound. Our results reveal that IP3 must release Ca2+ locally in the dendritic spines to produce LTD and indicate that one function of dendritic spines is to target IP3-mediated Ca2+ release to the proper subcellular domain.

2-Amino-5-phosphonovalerate↗
PubMed2000

Regulation of keratinocyte function by growth factors.

Various kinds of growth factors are involved in the regulation of human keratinocyte function. Among them, the epidermal growth factor (EGF) family and the transforming growth factor-beta (TGF-beta) family play central roles, providing dual-mode regulation of keratinocyte growth through the proliferation-stimulating effect of EGF and the proliferation-inhibiting effect of TGF-beta. Human keratinocytes synthesize four EGF family growth factors, TGF-alpha, amphiregulin, HB-EGF and epiregulin, which efficiently regulate keratinocyte growth and differentiation via auto- and cross-induction pathways. Human keratinocytes also synthesize TGF-beta1 and TGF-beta2, which are potent inhibitors of human keratinocytes. These intrinsic EGF family growth factors and TGF-betas are responsible for the autonomous growth regulation of keratinocytes.

Animals↗
PubMed2000

Synthesis and biological evaluations of C-23-modified 26,26,26,27,27,27-F6-vitamin D3 analogues.

A convenient synthetic method which could allow flexible modification at C-23 of 26,26,26,27,27,27-hexafluoro-1alpha,25-dihydroxyvitamin D3 (3) has been developed. An effective construction of hexafluoroacetone (HFA) aldol part on the side chain of 10 was achieved by aldol reaction with HFA gas. This route is also attractive as an approach to diverse 26,27-modified vitamin D3 analogues. The preliminary biological activities of 23-modifed 26,27-F6 vitamin D3 analogues are evaluated. The potency of VDR affinities of the C-23-substituted analogues (keto group (4); OH group (5a,5b); fluorine atom (6a,6b); and oxetane ring (7a,7b)) was found to vary depending upon both the nature and stereochemistry of the substituents. In contrast, the HL-60 cell differentiation property was less varied than VDR affinity, and depended upon the nature rather than the stereochemistry of the substituents.

Acetone↗