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Biomedical subjects

H Imamura

Publications and source records attributed to H Imamura.

At least 199 records · Page 11Linked to original sources
PubMed1997

[Re-expansion pulmonary edema after emergency thoracotomy for spontaneous hemopneumothorax: a case report].

A 44-year-old man was admitted to out hospital complaining of chest pain and increasing dyspnea. Chest X-ray on admission revealed a collapsed lung and an air fluid line in the left hemothorax. Following blood transfusion because of 2,000 ml hemorrhagic pleural fluid, emergent surgery was carried out. At operation, a bleeding artery originating from the apex of the thoracic cavity and a bulla on the upper lobe were noticed. After extubation of endotracheal tube, he offered severe dyspnea with hypoxia. The chest X-ray showed figure of pulmonary edema in the left lower lobe. Patient was managed by oxygen, steroid, and urinastatin. On the 3rd operative day, pulmonary edema was disappeared. It should be kept in the mind that the re-expansion pulmonary edema occurred in patients with spontaneous hemopneumothorax of less than 3 days of duration.

Adult↗
PubMed1997

[A case of recurrent bronchogenic cyst 15 years after initial operation].

There are few reports on the postoperative recurrence of bronchogenic cysts. We conducted a re-operation on a 57-year-old man with a bronchogenic cyst 15 years after an initial operation. His history showed an earlier operation for a bronchogenic cyst at the age of 42 at another hospital. 15 years after this initial operation, he suffered from common cold like symptoms, and was referred to our hospital, because of an abnormal shadow on his chest X-ray. A chest CT and MRI revealed an oval tumor just under the right intermediate bronchus. We suspected it was a recurrence of the bronchogenic cyst, and an operation was performed. The cyst was firmly adhered to the lung, and at the upper site of the cyst, a region adjacent to the intermediate bronchus was adhered to the bronchial wall. The histological findings were similar to those of 15 years previously. The cyst wall lined with pseudostratified columnar ciliary epithelium with muscular layer, which led to a diagnosis of a bronchogenic cyst. Congenital cysts, including bronchogenic cysts, are considered to originate in abnormal primordia. If there are remaining abnormal primordia, a recurrence of the disease can occur.

Bronchogenic Cyst↗
PubMed1997

[A surgical case of intrapericardial inferior vena cava injury complicating liver injury caused by a blunt trauma].

A 63-year-old man was brought to our hospital 20 minutes after sustaining blunt injury. He had been struck by a steel frame weighing about 700 kg that had fallen from a height of 2 meters. On admission, he was in cardiogenic shock with a systolic pressure of 70 mmHg and a pulse rate of 130 beats/minute. There was no apparent open wound and no brain injury was suspected. Echocardiography and chest computed tomogram showed cardiac tamponade, and abdominal computed tomogram showed liver injury. We performed emergency operation under cardio-pulmonary bypass standby. Laceration of the inferior vena cava at the right atrium junction was noticed. We had to perform IVC repair under cardio-pulmonary bypass because of massive bleeding. Liver injury was repaired after neutralization of systemic heparinazation. The patient developed respiratory, hepatic and renal failure during his postoperative course; however, he was discharged on postoperative day 39. Intrapericardial IVC injury caused by blunt trauma is a very rare event. Reconstruction can be performed successfully under cardio-pulmonary bypass.

Abdominal Injuries↗
PubMed1997

[A case of invasive thymoma that recurred with pericardial effusion 15 years postoperatively].

We treated a 74-years-old male who had recurrence with pericardial effusion and a tumor between the pulmonary artery and left atrium 15 years after operation for invasive thymoma complicated by myasthenia gravis. Despite pericardial drainage, CDDP infusion, and radiation therapy for the tumor, the patient died due to pneumonia after 1 and half years. Long-term observation is considered to be needed after surgical resection of thymoma for recurrence or multiple oncogenesis in ectopic thymus.

Aged↗
PubMed1997

[A case of complete remission of gastric endocrine cell carcinoma with multiple bone metastasis by combination chemotherapy and high-dose chemotherapy with autologous peripheral blood stem cell transplantation].

A 31-year-old man was admitted to our hospital complaining of epigastric discomfort and severe lumbago. An upper gastrointestinal endoscopy revealed several submucosallike tumors. Histologic examination of biopsy specimens confirmed the presence of endocrine cell carcinoma. Gallium scintigraphy and CT revealed multiple bone metastasis. He was treated with 6 cycles of combination chemotherapy consisting of CDDP, etoposide, CPA, EPI and VCR. Both gastric tumors and bone metastasis completely disappeared. After 7 cycles of the chemotherapy, he was treated with HDCT with PBSCT. There was no severe complication. This result suggested that the combination of conventional chemotherapy and HDCT with PBSCT was useful in cancer patients with poor prognoses, such as advanced gastric endocrine cell carcinoma.

Adult↗
PubMed1996

Bni1p implicated in cytoskeletal control is a putative target of Rho1p small GTP binding protein in Saccharomyces cerevisiae.

The RHO1 gene encodes a homolog of mammalian RhoA small GTP binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth sites, including the bud tip and the cytokinesis site, and is required for bud formation. We have recently shown that Pkc1p, a yeast homolog of mammalian protein kinase C, and glucan synthase are targets of Rho1p. Using the two-hybrid screening system, we cloned a gene encoding a protein which interacted with the GTP-bound form of Rho1p. This gene was identified as BNI1, known to be implicated in cytokinesis or establishment of cell polarity in S.cerevisiae. Bni1p shares homologous domains (FH1 and FH2 domains) with proteins involved in cytokinesis or establishment of cell polarity, including formin of mouse, capu and dia of Drosophila and FigA of Aspergillus. A temperature-sensitive mutation in which the RHO1 gene was replaced by the mammalian RhoA gene showed a synthetically lethal interaction with the bni1 mutation and the RhoA bni1 mutant accumulated cells with a deficiency in cytokinesis. Furthermore, this synthetic lethality was caused by the incapability of RhoA to activate Pkc1p, but not glucan synthase. These results suggest that Rho1p regulates cytoskeletal reorganization at least through Bni1p and Pkc1p.

Base Sequence↗
PubMed1996

Inhibition by bertosamil of cardiac responses to pinacidil or Bay k 8644 in isolated dog atria and ventricles.

We investigated the effects of a novel bradycardiac agent, bertosamil (3-isobutyl-7-isopropyl-9,9-pentamethylene-3,7-diazabicyclo[3.3.1] nonane sesquihydrogenfumarate), on the sinus rate and atrial contractile force and the left ventricular contractile force in isolated, blood-perfused dog hearts and the blocking effects of bertosamil on the chronotropic and inotropic responses to pinacidil and Bay k 8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)- piridine-5-carboxylate). Bertosamil (0.1-100 nmol) caused transient positive, followed by continuous negative, chronotropic responses and positive inotropic responses in atria, and increased the left ventricular contractile force. Neither propranolol nor atropine affected the cardiac responses to bertosamil. Bertosamil (3-100 nmol) dose dependently attenuated the negative chronotropic and inotropic responses to pinacidil but not to acetylcholine. Bertosamil at a high dose attenuated the positive cardiac responses to Bay k 8644, norepinephrine and isoproterenol. These results suggest that bertosamil inhibits negative cardiac responses mediated by an ATP-sensitive K+ channel but not an acetylcholine muscarinic receptor and, at a high dose, attenuates the L-type Ca2+ channel-mediated positive cardiac responses in isolated dog hearts.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1996

Rom1p and Rom2p are GDP/GTP exchange proteins (GEPs) for the Rho1p small GTP binding protein in Saccharomyces cerevisiae.

The RHO1 gene encodes a homolog of the mammalian RhoA small GTP binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth site and is required for bud formation. Multicopy suppressors of a temperature-sensitive, dominant negative mutant allele of RHO1, RHO1(G22S, D125N), were isolated and named ROM (RHO1 multicopy suppressor). Rom1p and Rom2p were found to contain a DH (Dbl homologous) domain and a PH (pleckstrin homologous) domain, both of which are conserved among the GDP/GTP exchange proteins (GEPs) for the Rho family small GTP binding proteins. Disruption of ROM2 resulted in a temperature-sensitive growth phenotype, whereas disruption of both ROM1 and ROM2 resulted in lethality. The phenotypes of deltarom1deltarom2 cells were similar to those of deltarho1 cells, including growth arrest with a small bud and cell lysis. Moreover, the temperature-sensitive growth phenotype of deltarom2 was suppressed by overexpression of RHO1 or RHO2, but not of CDC42. The glutathione-S-transferase (GST) fusion protein containing the DH domain of Rom2p showed the lipid-modified Rholp-specific GDP/GTP exchange activity which was sensitive to Rho GDP dissociation inhibitor. These results indicate that Rom1p and Rom2p are GEPs that activate Rho1p in S.cerevisiae.

Amino Acid Sequence↗
PubMed1996

Relation between Locoregional Hyperthermic Area Detected by Contact Thermography and the Maximum Density of Tumor Stain Obtained by IV-DSA in Breast Cancer Patients.

We studied the significance of the locoregional hyperthermic area observed by contact thermography in relation to the maximum density of tumor enhancement obtained by IV-DSA. The subjects were 34 patients with primary breast cancer. The thermal difference between the locoregional hyperthermic area and the surrounding mammary tissues was obtained, and the maximum density of tumor stain on IV-DSA was calculated from the time-density curve. Twenty-three (67.6%) patients had a locoregional hyperthermic area corresponding to the tumor. The higher the degree of thermal difference between the hyperthermic area and the surrounding tissues, the higher the maximum density of tumor enhancement. As the maximum density of tumor stain is considered to reflect the vascularity of the tumor, the degee of the locoregional hyperthermic area obtained by thermography may also reflect tumor vascularity.

Journal Article↗
PubMed1996

Negative chronotropic and dromotropic effects of E-4031, an IKr blocker, on the atrioventricular node in anesthetized dog hearts.

To investigate the effect of the delayed rectifier K+ current (IK) on the atrioventricular (AV) node of the heart in situ, we studied the direct effects of (1-[2-(6-methyl-2-pyridyl)ethyl]-4-(methylsulfonyl-aminobenzoyl)piperidi ne (E-4031), an IKr (a rapid type of IK) blocker, on the AV junctional rate, atrio-His interval (AH interval), and right ventricular pressure, and the cardiac responses to sympathetic nerve stimulation in the anesthetized dog heart. AV junctional rhythm was induced by clamping the sinoatrial (SA) pacemaker area. E-4031 (0.01-3 mumol/kg, i.v.) attenuated the AV junctional rate dose dependently. The junctional negative chronotropic effect was less than the decrease in sinus rate induced by E-4031 in the same doses. E-4031 did not affect the junctional rate increased by sympathetic stimulation. In the paced heart, E-4031 slightly increased the AH interval but did not change right ventricular pressure responses. E-4031 attenuated neither positive dromotropic nor positive ventricular pressure responses to sympathetic stimulation. After E-4031 treatment, zatebradine (a hyperpolarization-activated current blocker) additively decreased the junctional rate and the junctional positive chronotropic responses to sympathetic stimulation. These results suggest that IKr has much less effect on AV nodal pacemaker activity than on SA nodal pacemaker activity, and an IKr blocker, E-4031, unlike zatebradine, does not antagonize the junctional positive chronotropic responses to sympathetic activation in anesthetized dog heart.

Anesthesia↗
PubMed1996

Radiofrequency catheter ablation of supraventricular tachycardias in patients with hypertrophic cardiomyopathy.

Supraventricular tachycardias, as well as ventricular tachycardia, are critical patients with hypertrophic cardiomyopathy. Anti-arrhythmic agents often induce arrhythmias, known as pro arrhythmia. Radiofrequency catheter ablation has become a well-established therapy for the treatment of supraventricular tachycardia. The reported success rate is over 90%, although catheter mapping in the left ventricle is difficult in patients with hypertrophic cardiomyopathy because of the marked left ventricular wall thickening associated with bizarre myocardial hypertrophy with disorganization, the abundant capillary muscle networks, and annoying ventricular arrhythmias. This report documents catheter mapping technique of radio frequency ablation in patients with hypertrophic cardiomyopathy and supraventricular tachycardias.

Adult↗
PubMed1996

Large spleno-caval shunt not accompanied by cirrhosis or encephalopathy.

A 40-year-old man with a large spleno-caval shunt through the azygos vein is described. This was considered a rare case, because the patient had no accompanying advanced liver disease, or episodes of hepatic encephalopathy. During checks after abnormal liver function test results, a shunt vessel was detected incidentally by ultrasonography. Computed tomography, magnetic resonance imaging, and angiography demonstrated that it was a large shunt between the splenic vein and superior vena cava through the coronary and azygos veins. The patient was a hepatitis B virus carrier and was positive for anti-HBe, and had a history of heavy drinking. However, on laparoscopic examination, the liver was not cirrhotic and the biopsy revealed only mild chronic hepatitis without bridging fibrosis. There were no esophageal varices or hepatosplenomegaly. On hemodynamic evaluation, the wedge hepatic vein pressure was slightly elevated and hepatic blood flow was reduced to half the normal value. Despite the large portal-systemic shunt, the patient had no history or signs of hepatic encephalopathy. The clinical features of this rare case are discussed.

Adult↗
PubMed1996

Effects of high-density lipoproteins on intracellular pH and proliferation of human vascular endothelial cells.

We investigated the effects of high-density lipoprotein (HDL) on the intracellular pH ([pH]i), and on the proliferation of human vascular endothelial cells (HUVEC), as well as on their production of prostacyclin (PGI2). The [pH]i was slightly acidified when extracellular Ca2+ was chelated with EGTA. Pretreatment of HUVEC with amiloride, the Na+/H+ exchange inhibitor, caused the [pH]i to become strongly acidic. The addition of HDL produced a biphasic shift in [pH]i, with a brief initial acidification followed by a rapid alkaline shift. The initial decrease in [pH]i was abolished in the cells pretreated with EGTA, and subsequent alkalinization was inhibited. The alkalinization of [pH]i disappeared in the cells pretreated with amiloride. These results suggest that [pH]i depends mainly on Na+/H+ exchange and partially on the extracellular Ca2+ of the HUVEC either in the resting unstimulated state or during HDL stimulation. In contrast, the addition of LDL produced an acidification of [pH]i, which was increased by LDL in the Ca(2+)-free condition. In the cells pretreated with amiloride, [pH]i was not further acidified by LDL. As a result, HDL promoted the proliferation of cells, an action that was inhibited by pretreatment with EGTA. However LDL inhibited cell proliferation, an action unaffected by EGTA pretreatment. The addition of HDL also enhanced the generation of prostacyclin in endothelial cells, the enhancement of PGI2 generation resulted from an increase in the release of Ca2+ from storage sites, due not only to an increased production of inositol 1,4,5-trisphosphate (IP3), but also to the alkalinization of [pH]i. These effects may be involved in the mechanism of HDL's anti-atherosclerotic action.

Amiloride↗
PubMed1996

Acute presynaptic inhibition by doxorubicin of negative chrono- and inotropic responses to parasympathetic nerve stimulation in isolated, blood-perfused dog atrium.

The clinical use of doxorubicin, an anthracycline antineoplastic agent, is limited by its cardiotoxicity. Although several previous reports have shown neurotoxic effects of doxorubicin, there is little information about the acute effects of doxorubicin on the autonomic nerve functions in the heart. Accordingly, to evaluate the effects of doxorubicin on the cardiac responses to autonomic nerve activation, we studied the effects of doxorubicin on the negative chrono- and inotropic responses to intracardiac parasympathetic nerve stimulation and acetylcholine (ACh), and the positive chrono- and inotropic responses to norepinephrine (NE) in the isolated, blood-perfused dog atrium. Doxorubicin (0.01-3 mumol), injected into the sinus node artery of the isolated atrium, induced negative inotropic effects dose dependently and weak negative chronotropic effects. Doxorubicin inhibited the negative chrono- and inotropic responses to parasympathetic nerve stimulation dose dependently. However, doxorubicin affected neither the negative chrono- and inotropic responses to ACh nor the positive chrono- and inotropic responses to NE. These results indicate that doxorubicin interacts with neither muscarinic receptors nor beta-adrenoceptors and suggest that doxorubicin inhibits the negative cardiac responses to parasympathetic nerve activation due to the inhibition of ACh release from nerve varicosities in the heart.

Acetylcholine↗
PubMed1996

Atrioventricular junctional rhythm induced by sympathetic stimulation in E-4031-treated dog hearts.

To investigate the role of delayed rectifier potassium current (IK) on the sympathetic control of the heart, we studied the effects of E-4031, a blocker of the rapidly activating type of IK (IKr), on the chronotropic, dromotropic, and inotropic responses to sympathetic nerve stimulation in the autonomically decentralized hearts of open-chest anesthetized dogs, E-4031 (0.01-3 mumol/kg intravenously, i.v.) decreased the heart rate (HR) dose dependently without affecting other cardiac functions. After E-4031 treatment, cardiac sympathetic nerve stimulation changed the sinus rhythm to the atrioventricular (AV) junctional rhythm in 6 of 11 anesthetized dogs (55%). In three of six junctional rhythm hearts, sinus rhythm supervened during sympathetic stimulation for 2 min. The number of pacemaker shifts to junctional rhythm increased as the dose of E-4031 was increased. However, E-4031 attenuated neither the positive chronotropic, dromotropic, nor right atrial and ventricular inotropic responses to sympathetic nerve stimulation. These results suggest that IKr inhibition may induce the AV junctional rhythm due to the combination of the different participation of IKr, the different resting potentials, and the different sensitivity to sympathetic activation among cardiac pacemaker cells.

Animals↗
PubMed1996

Relationship of cigarette smoking to blood pressure and serum lipids and lipoproteins in men.

1. The relationship of cigarette smoking to blood pressure and serum lipids and lipoproteins was studied in 7608 men, ranging from 40 to 59 years of age. Analyses were performed separately for non-drinkers and drinkers. 2. After adjusting age and body mass index (BMI) in non-drinkers and age, BMI and alcohol intake in drinkers in forward stepwise multiple regression analysis, there was a dose-dependent negative relationship between cigarette smoking and diastolic blood pressure (DBP) and high density lipoprotein cholesterol (HDL-C), regardless of drinking habit. There was a dose-dependent positive relationship between cigarette smoking and the ratio of total cholesterol (TC) to HDL-C (TC:HDL-C) in non-drinkers, but not in drinkers. There was a dose-dependent negative relationship between cigarette smoking and TC and a positive relationship between cigarette smoking and triglycerides (TG) in drinkers, but not in non-drinkers. 3. After matching age and BMI in non-drinkers, subjects who smoked more than 30 cigarettes/day had significantly lower mean values of systolic blood pressure (SBP; 4.3%; P < 0.05), DBP (3.0%; P < 0.01) and HDL-C (15.5%; P < 0.01) and higher mean values of TC:HDL-C (25.0%; P < 0.01), TG (46.8%; P < 0.01) and beta-lipoprotein (12.0%; P < 0.01) than non-smokers. In drinkers, after matching age, BMI, and alcohol intake, subjects who smoked more than 30 cigarettes/day had significantly lower mean values of SBP (2.8%; P < 0.05), DBP (4.8%; P < 0.01), HDL-C (17.3%; P < 0.01) and TC (4.4%; P < 0.01) and higher mean values of TC:HDL-C (15.4%; P < 0.01) and TG (45.1%; P < 0.01) than non-smokers. 4. Although the results are somewhat variable, the present study reveals that cigarette smoking is negatively associated with SBP and DBP and unfavourably associated with lipids and lipoproteins, regardless of drinking habit.

Adult↗
PubMed1996

Eosinophilia in premature infants: correlation with chronic lung disease.

We attempted to clarify the possible pathophysiological significance of eosinophilia in bronchopulmonary dysplasia (BPD). The subjects studied were 17 premature infants, i.e. seven with respiratory distress syndrome (RDS) followed by bronchopulmonary dysplasia (the BPD group: four with stage IV and three with stage III BPD) and 10 infants without BPD (the non-BPD group), who comprised seven with RDS, two with meconium aspiration syndrome and one with transient tachypnea of the newborn. Peripheral eosinophil counts, the number of nuclei of eosinophils and serum eosinophilic cationic protein (ECP) levels, and ECP and polymorphonuclear leukocyte (PMN) elastase levels of intratracheal aspirates (TA) were determined once a week during the first 4 weeks of life. Peripheral eosinophil counts were higher in infants with BPD than those in the non-BPD group. Hypersegmented nuclei of peripheral eosinophils with more than four nuclei were more frequently present in the infants with BPD. A good correlation was observed between peripheral eosinophil counts and serum ECP levels. ECP levels of the TA in the infants with BPD were significantly elevated. There was a good correlation between ECP and PMN elastase levels of the TA. Lung tissue specimens of two infants of the BPD group, both of whom had patent ductus arteriosus (PDA), were obtained from the lower portion of the left lung when they underwent an operative procedure for PDA at 24 and 25 days of life, respectively. Immunohistochemical staining of eosinophil-derived granular major basic protein (MBP) was performed on the lung tissue specimens. Infiltration of a few MBP-staining eosinophils was observed on the specimens from both infants. Our results suggest that peripheral eosinophils in sick premature infants may be activated and appear to be correlated with the severity of BPD. Further studies will be needed to more clarify the physiological role of eosinophils in premature infants.

Blood Proteins↗