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Biomedical subjects

H Imamura

Publications and source records attributed to H Imamura.

At least 163 records · Page 9Linked to original sources
PubMed1998

[One stage operation for aneurysm of the diverticulum of the ductus arteriosus and coronary artery bypass grafting].

Aneurysm of the diverticulum of the ductus arteriosus in the adult is rare. One stage operation for aneurysm of the diverticulum of the ductus arteriosis and coronary artery bypass grafting (CABG) is reported. A 61-year-old man was admitted for diagnosis of thoracic aneurysm on chest X-ray and CT. Chest CT scan showed an aneurysm above the left main pulmonary artery. An aortography showed the left vertebral artery originated directly from the aortic arch and a saccular aneurysm arising from the aortic isthmus and lesser curvature of the aortic arch. Coronary arteriography showed 75% stenosis at the right coronary artery (seg. #1) and 75% stenosis at the left anterior descending artery. Operation was performed through a median sternotomy. The aneurysm of 6 to 3 cm was located between the aortic isthmus and left pulmonary artery. Ascending aorta and right atrium were used to institute cardiopulmonary bypass (CPB). CABG (LITA to #7, SVG to #4 PD) was performed. Arterial cannulation was then switched to the left femoral artery. The proximal aorta was cross-clamped between the left vertebral artery and the left subclavian artery under the partial CPB, and the distal aorta was occluded with a occulusive balloon catheter via the right femoral artery. The selective left axillar artery cannulation was performed to perfuse LITA. The aneurysm was resected and closed with a patch. His post-operative course was uneventful.

Aortic Aneurysm↗
PubMed1998

[The pharmacokinetics of a fibrin adhesive agent applied to the rat lung].

PURPOSE: Although fibrin adhesive agents are frequently applied in the clinical setting, their pharmacokinetics in vivo remain to be clarified. We examined the pharmacokinetics of a fibrin adhesive agent applied to the rat lung. MATERIAL AND METHODS: Male Sprague Dawley rats were used. Under general anesthesia, left thoracotomy was performed, and the left lung was incised about 1 cm length and 1 mm depth. This incision was sutured with 9-0 nylon, and a fibrin adhesive agent containing 125I-labeled fibrinogen was applied. On days 1, 3, 7 and 14 after the operation, the left lung, right lung, liver and kidneys were collected. The tissue distribution of radioactivity was examined by determining the 125I levels in each organ as well as calculating the tissue levels of radioactivity. RESULTS: The tissue distribution of radioactivity in the left lung was significantly higher than those in other organs on days 1 and 3. The tissue levels of radioactivity in the left lung was significantly higher than those in other organs on days 1, 3 and 7. Each value rapidly decreased after day 7. CONCLUSION: A fibrin adhesive agent applied to the lung significantly remained at a high level through the inflammatory and proliferative phases followed by a prompt decrease before the phase of cicatrization. Therefore it is considered that a fibrin adhesive agent applied to the lung is satisfactory for the healing of wounds.

Animals↗
PubMed1998

Comparison of relapse and long-term survival between pylorus-preserving and Whipple pancreaticoduodenectomy in periampullary cancer.

BACKGROUND: Whether long-term survival and type of recurrence in periampullary cancer are influenced by the type of surgical procedure or not is still obscure. The purpose of this review was to analyze the results at a single institution. METHODS: Between 1982 and 1996, 113 consecutive patients with either distal bile duct or ampullary cancers underwent either pylorus-preserving pancreaticoduodenectomy (PPPD) or the Whipple procedure. The median follow-up was 30 months (range 12 to 150). Patient records were reviewed to determine type of recurrence and survival. RESULTS: In distal bile duct or ampullary cancers, comparison of actuarial survival curves between PPPD and the Whipple operation revealed no significant differences. Even in node-positive patients, the 5-year survival rates did not differ significantly between those undergoing PPPD or the Whipple operation. Tumor recurrence was not correlated with the operative method, although among types of tumor recurrence, the rate of blood-borne metastasis was higher in distal bile duct or ampullary cancers. CONCLUSIONS: PPPD is an acceptable alternative to the Whipple procedure in the treatment of periampullary cancer. Long-term survival and type of recurrence were not influenced by these types of surgical procedures.

Adult↗
PubMed1998

A case of primary cardiac lymphoma: utility of serum soluble interleukin-2 receptor for noninvasive diagnosis.

A 70-year-old woman was referred to us for the investigation of a tumor mass in the right sided of the heart. LDH and soluble interleukin-2 receptor (sIL2r) were elevated. She died one day after the initiation of radiation therapy because of intractable cardiogenic shock. Primary cardiac lymphoma was identified at autopsy. Measurement of serum sIL2r lead us to the antemortem diagnosis of the disease.

Aged↗
PubMed1998

Novel dithiocarbamate carbapenems with anti-MRSA activity.

A new series of 1beta-methyl carbapenems, in which a disubstituted-aminothiocarbonylthio moiety was attached to the C-2 position of the carbapenem nucleus, were prepared and evaluated for anti-MRSA activity. These derivatives showed good in vitro antibacterial activity against high-level MRSA, and the finding of good affinity for PBP-2' supported these results. Some of the compounds having favorable protein-binding affinity showed excellent in vivo anti-MRSA activity.

Animals↗
PubMed1998

Effect of intrathecal nimodipine on spinal cord blood flow and evoked potentials in the normal or injured cord.

A method was developed for administering intrathecal pharmacotherapy in a rat model of spinal cord injury. The effects of intrathecal administration of nimodipine on spinal cord blood flow (SCBF) and evoked potentials (EPs) were measured in the normal and injured spinal cord. It had previously been shown that systemic nimodipine caused severe hypotension after spinal cord injury. After baseline SCBF and EPs, 15 uninjured rats were blindly allocated to one of three groups: one placebo group (n = 5); and two groups with intrathecal nimodipine, 0.05 mg/kg (n = 5), or 0.2 mg/kg (n = 5). Ten other rats received a 35 g acute clip compression injury of the spinal cord for 1 minute and, were allocated to one of two groups: placebo (n = 5); and intrathecal nimodipine 0.05 mg/kg (n = 5) given 60 min after injury. In the uninjured groups, neither 0.05 nor 0.2 mg/kg of nimodipine increased SCBF during, or 30 min after, intrathecal infusion. However, the mean arterial blood pressure (MABP) decreased significantly to 69.73.1% after the infusion of 0.2 mg/kg nimodipine and did not recover by 98 min. In all three groups of uninjured rats, the amplitude of the cerebellar EP was decreased 30 min after infusion. After spinal cord injury, there were significant decreases in MABP, SCBF and EP amplitude in both placebo and treatment groups, but there was no therapeutic benefit from nimodipine. Thus, intrathecal infusion of nimodipine did not prevent the hypotension encountered with systemic administration and exerted no beneficial effect on SCBF or EPs after acute spinal cord injury.

Animals↗
PubMed1998

Rho and Rab small G proteins coordinately reorganize stress fibers and focal adhesions in MDCK cells.

The Rho subfamily of the Rho small G protein family (Rho) regulates formation of stress fibers and focal adhesions in many types of cultured cells. In moving cells, dynamic and coordinate disassembly and reassembly of stress fibers and focal adhesions are observed, but the precise mechanisms in the regulation of these processes are poorly understood. We previously showed that 12-O-tetradecanoylphorbol-13-acetate (TPA) first induced disassembly of stress fibers and focal adhesions followed by their reassembly in MDCK cells. The reassembled stress fibers showed radial-like morphology that was apparently different from the original. We analyzed here the mechanisms of these TPA-induced processes. Rho inactivation and activation were necessary for the TPA-induced disassembly and reassembly, respectively, of stress fibers and focal adhesions. Both inactivation and activation of the Rac subfamily of the Rho family (Rac) inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly. Moreover, microinjection or transient expression of Rab GDI, a regulator of all the Rab small G protein family members, inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly, indicating that, furthermore, activation of some Rab family members is necessary for their TPA-induced reassembly. Of the Rab family members, at least Rab5 activation was necessary for the TPA-induced reassembly of stress fibers and focal adhesions. The TPA-induced, small G protein-mediated reorganization of stress fibers and focal adhesions was closely related to the TPA-induced cell motility. These results indicate that the Rho and Rab family members coordinately regulate the TPA-induced reorganization of stress fibers and focal adhesions that may cause cell motility.

Actins↗
PubMed1998

Successful stenting of bilateral renal artery stenosis due to fibromuscular dysplasia assessed by use of pressure guidewire technique: a case report.

An 18-year-old woman with renovascular hypertension had stenosis due to fibromuscular dysplasia (FMD) of the bilateral renal arteries, and this did not respond to conventional balloon angioplasty owing to marked elastic recoil. Implantation of Palmaz-Schatz stents resulted in successful dilation of the stenosis and remission of hypertension. Transstenotic pressure gradients were measured by use of a pressure-monitoring guidewire. It is suggested that stenting is a very useful adjunct to balloon angioplasty in the treatment of renal artery stenosis due to FMD.

Adolescent↗
PubMed1998

Primary pulmonary artery sarcoma.

A 66-year-old woman with a history of mitral valve replacement with a Starr-Edwards ball valve 25 years ago was treated for refractory heart failure but died of right heart failure. At autopsy, primary pulmonary artery sarcoma was found in the right ventricular outflow tract, main pulmonary trunk, and bilateral pulmonary artery, and had invaded the aortic arch. The pathohistologic diagnosis was osteosarcoma. Echocardiography, chest computed tomography and right ventriculography performed 1 year before death did not reveal the presence of a tumor in the pulmonary artery. The history of this patient shows that primary pulmonary artery sarcoma grows rapidly, with, in this case, the patient dying within 1 year of its appearance.

Aged↗
PubMed1998

Familial sick sinus syndrome with atrioventricular conduction disturbance.

A family with sick sinus syndrome is presented: a mother and her 2 daughters affected with sinus node dysfunction. Electrophysiological studies revealed abnormal atrioventricular conduction in the 2 daughters. All 3 individuals were implanted with a permanent pacemaker to relieve their symptoms. Endomyocardial biopsy from the right ventricle of one daughter showed disarrangement, degeneration, myocyte necrosis and interstitial fibrosis suggestive of myocardial disease.

Adult↗
PubMed1998

Inhibition of delayed rectifier K+ current by dofetilide and E-4031 differentially affects electrical cardiac responses to vagus stimulation in anesthetized dogs.

Vagal activation influences various cardiac functions as well as occurrence of arrhythmias. Inhibition of a rapid type of delayed rectifier K+ current (I[Kr]) has been reported to be effective for the treatment of both ventricular and supraventricular arrhythmias. However, it is unknown how I[Kr] inhibition modulates the cardiac responses to vagal activation in situ. We analyzed the effects of I[Kr] inhibitors, dofetilide and E-4031, and a class I antiarrhythmic agent, disopyramide, on electrical cardiac responses to vagus stimulation in anesthetized dogs. Dofetilide (0.003-0.3 micromol/kg, i.v.), E-4031 (0.01-1 micromol/kg, i.v.) and disopyramide (2.9-29 micromol/kg, i.v.) prolonged sinus cycle length (SCL), right atrial effective refractory period (AERP) and ventricular effective refractory period (VERP) dose-dependently. During cervical vagus stimulation-induced prolongation of SCL, atrio-His (AH) interval and VERP and shortening of AERP, dofetilide and E-4031 inhibited the prolongation of SCL but potentiated the shortening of AERP. Dofetilide and E-4031 did not affect prolongations of AH interval and VERP. On the other hand, disopyramide inhibited all electrical cardiac responses to vagus stimulation. These results suggest that I(Kr) inhibition differentially modulate cardiac responses to vagus activation probably due to a different role of I(Kr) in each cardiac function in the heart in situ.

Animals↗
PubMed1998

Cloning of the gene for inorganic pyrophosphatase from a thermoacidophilic archaeon, Sulfolobus sp. strain 7, and overproduction of the enzyme by coexpression of tRNA for arginine rare codon.

The gene encoding an extremely stable inorganic pyrophosphatase from Sulfolobus sp. strain 7, a thermoacidophilic archaeon, was cloned and sequenced. An open reading frame consisted of 516 base pairs coding for a protein of 172-amino acid residues. The deduced sequence was supported by partial amino acid sequence analyses. All the catalytically important residues were conserved. A unique 17-base-pair sequence motif was found to be repeated four times in frame in the gene, encoding a cluster of acidic amino acids essential for the function. Although the codon usage of the gene was quite different from that of Escherichia coli, the gene was effectively expressed in E. coli. Coexpression of tRNA(Arg), cognate for the rare codon AGA in E. coli, however, further improved the production of the enzyme, which occupied more than 85% of the soluble proteins obtained after removal of heat denatured E. coli proteins.

Amino Acid Sequence↗
PubMed1998

Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine.

OBJECT: Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. METHODS: The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases). CONCLUSIONS: The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

Adult↗
PubMed1998

Staged hepatectomy after emergency transcatheter arterial embolization for ruptured hepatocellular carcinoma.

BACKGROUND: Staged hepatectomy after emergency transcatheter arterial embolization (TAE) has been advocated in ruptured hepatocellular carcinoma (HCC). However, there have been no reports of clinical series of this strategy. The purpose of this study was to evaluate the protocol of this therapeutic strategy. METHODS: Sixteen patients with suspected rupture of HCC were included in the study. After emergency TAE, tumor resectability was assessed, followed by staged hepatectomy or repeated TAE. The patients were reevaluated with regard to rupture of HCCs. RESULTS: Primary hemostasis was achieved successfully in all patients. Eleven patients were finally judged to have experienced HCC rupture. Seven of them underwent staged hepatectomy; the other four underwent repeated TAE because their tumors were considered unresectable. Survival time tended to be longer, but not to a significant extent, in patients who underwent hepatectomy (range, 139 to 1527 days; median, 375 days) than in those treated by TAE alone (range, 43 to 1317 days; median, 158 days). CONCLUSIONS: Staged hepatectomy after TAE is a rational treatment for patients with ruptured HCC. Although TAE is highly effective for initial hemostasis, hepatectomy appears to provide better long-term survival.

Adult↗
PubMed1998

[Aortic valvular vegetation in annuloaortic ectasia due to idiopathic cystic medial necrosis: a case report].

Annuloaortic ectasia is often accompanied by Marfan syndrome and associated with infective endocarditis usually involving the mitral valves. We treated a patient with annuloaortic ectasia due to idiopathic cystic medial necrosis who developed congestive heart failure with aortic valvular vegetation. A 56-year-old man had dyspnea on effort since the beginning of January, 1997 and was admitted to our hospital on April 6, 1997 because of orthopnea. The diagnosis was congestive heart failure due to severe aortic regurgitation with annuloaortic ectasia detected by echocardiography. Medication and rest after hospitalization relieved his symptoms but congestive heart failure deteriorated after he had a high fever. At this time, a vegetation attached to the noncoronary cusp of the aortic valve was found which had not been detected on admission. Blood culture yielded Streptococcus sanguis. The diagnosis was infective endocarditis involving the aortic valve. Surgical correction (Bentall method) improved congestive heart failure and he was discharged on August 4, 1997 without recurrence of endocarditis. Infective endocarditis involving the aortic valves is a possible cause of development or deterioration of congestive heart failure in patients with annuloaortic ectasia.

Aortic Diseases↗
PubMed1998

Aorto-atrial fistula associated with recurrent aortic dissection after ascending aorta replacement.

A 70-year-old woman with a bicuspid aortic valve had undergone ascending aorta replacement for acute DeBakey type I dissection. Computed tomography and aortography 2 months after the operation revealed a thrombosed false lumen in the ascending aorta proximal to the prosthetic graft. However, recurrence of dissection was found at the aortic root proximal to the graft 4 years after the initial operation. Significant aortic stenosis was also noted. Despite intensive medical treatment, she had refractory and progressive heart failure. At the second surgery, an aorto-right atrial fistula, which probably was responsible for the severe heart failure was revealed. Closure of the aorto-right atrial fistula, and aortic root replacement were performed using Piehler's method, with a composite graft. The etiology and management of this rare case are discussed.

Aged↗