Biomedical subjects

H Imamura

Publications and source records attributed to H Imamura.

At least 235 records · Page 13Linked to original sources

PubMed1995

The failure of retrograde continuous warm-blood cardioplegia to resuscitate cardiac function in experimental acute coronary artery occlusion and reperfusion.

The effects of retrograde continuous warm-blood cardioplegia (RCWBC) on myocardial preservation during surgical revascularization for acute coronary artery occlusion were investigated using an isolated in-situ dog heart model. The left anterior descending artery (LAD) was occluded for 60 minutes followed by 60 minutes of cardioplegic arrest and reperfusion after release of the coronary artery occlusion. Thirty one animals were divided into 3 groups according to the manner of cardioplegic arrest. The first group of animals (n=10) received multiple doses of cold St. Thomas' Hospital solution delivered antegradely through the aortic root. The second group of animals (n=11) received the same dose of the crystalloid solution delivered retrogradely through the coronary sinus. The third group of animals (n=10) received RCWBC through the coronary sinus. In the animals which were capable of supporting the working mode after reperfusion (8 hearts in each group), regional myocardial function in the occluded LAD distribution measured by sonomicrometer as well as global myocardial function evaluated by left-ventricular stroke-work index were not significantly improved during reperfusion by RCWBC. Corresponding to the functional data, myocardial pH in the occluded LAD distribution was not significantly increased by RCWBC. Although RCWBC maintained myocardial pH in the circumflex artery distribution at a significantly higher level than the other two groups of hearts undergoing cold crystalloid cardioplegia, RCWBC resulted in a substantial decline of myocardial pH in the right-ventricular free wall. These results suggest that RCWBC after 60 minutes of LAD occlusion may not provide a significant benefit in myocardial preservation compared to cold crystalloid cardioplegia delivered through either an antegrade or retrograde manner.

Animals↗

PubMed1995

Inhibition of the subsidiary pacemaker activity by zatebradine, an If inhibitor, in the anesthetized dog heart.

To investigate the role of the hyperpolarization-activated current (If) on the subsidiary pacemaker activity of the heart, we studied the effects of an If inhibitor, zatebradine, and a L-type Ca channel inhibitor, verapamil, on the atrioventicular (AV) junctional rhythm and other cardiac responses to stimulation of the left ansa subclavia (LS) in the autonomically decentralized heart of open-chest anesthetized dog. AV junctional rhythm was induced by clamping the sinoatrial (SA) pacemaker region and confirmed by His-bundle electrograms. Zatebradine 0.1 and 0.3 mumol/kg intravenously (i.v.) similarly attenuated both the AV junctional rate and the increase in the junctional rate in response to LS. However, higher doses (1 and 3 mumol/kg i.v.) of zatebradine changed the junctional rhythm to the atrial rhythm in all cases and decreased the atrial rate further but not the increases in the atrial rate in response to LS. On the other hand, verapamil (0.06, 0.2, and 0.6 mumol/kg i.v.) attenuated the increase in the junctional rate induced by LS dose dependently but did not affect the junctional rate itself. After verapamil, zatebradine did not shift the pacemaker site during LS and it further attenuated the positive chronotropic response. These results demonstrate that zatebradine, an If inhibitor, inhibits subsidiary pacemaker activities as well as SA nodal pacemaker activity in situ and suggest that an inhibition of If alters the pacemaker sites due to the different participation of If among the cardiac pacemaker cells.

Anesthesia↗

PubMed1995

Intraoperative spinal sonography in the cervical anterior approach.

Intraoperative spinal sonography was used during cervical anterior approach procedures for cervical discectomy and osteophytectomy to demonstrate spinal pulsation, the protruded disc or osteophyte, the anterior subarachnoid space, and the spinal cord. Spinal pulsation was recognized in some cases before removal of the disc but the anterior subarachnoid space and spinal cord could not be observed. However, the latter were more clearly observed during removal of the disc and could be seen after total removal of the disc and osteophyte. This method allows confirmation of decompression and pulsation of the spinal cord without cutting and removal of the posterior longitudinal ligament.

Adult↗

PubMed1995

[Combined lung resection for advanced thoracic esophageal carcinoma].

We performed lung resection together with esophagectomy in 2 patients with advanced thoracic esophageal cancer. Both patients survived more than 2 years with no evidence of disease. The first case was a 60-year-old man who had a cancer lesion in middle of the intra-thoracic esophagus (Im) and the right lower lobe of the lung was involved. In March 1989, right lower lobectomy of the lung was performed with esophagectomy. Pathologic examination showed well differentiated squamous cell carcinoma invading the lung parenchyma and intrapulmonary lymph node. Postoperatively, 44 Gy of radiation and Peplomycin cancer chemotherapy was performed. The patient survived 51 months after surgery and died of chronic myelogenous leukemia. The second case was a 60-year-old man who underwent thoracic esophagectomy with resection of the involved pericardium and right lung in February 1992. Pathologic examination showed N3 lymph node metastasis. Postoperatively, the patient received 48 Gy of radiation and was free from cancer after 30 months. In conclusion, better surgical results are expected in cases of advanced thoracic esophageal cancer with lung involvement which can be completely resected en bloc with the primary tumor even in a3 cases than in those with aortic or tracheobronchial involvement.

Aged↗

PubMed1995

[Molecular biological mechanism of cancer metastasis and the prediction of metastasis in clinical cases].

An outline of the mechanism of cancer metastasis is presented from a molecular biological point of view, and the present state and future possibility of prediction about cancer metastasis in clinical cases is described. Cancer metastasis is developed through multiple steps. With the progress of studies on the mechanism of metastasis, the effort to predict cancer metastasis in clinical cases has progressed. Metastasis is formed in concern with many factors, so it may be highly difficult to explain clinical metastasis by a single factor. It will be important to comprehensively put many factors into consideration. For the preoperative diagnosis of the potential of metastasis, examination of specimens from endoscopic biopsy or blood serum will become more important.

Cell Adhesion Molecules↗

PubMed1995

[Pneumothorax with reduced pulmonary function complicated by MRSA pneumonia: a case report].

The occurrence of pneumothorax in patients with compromised lung function or severe pulmonary disease may be fatal. We describe a 77-year-old patient with MRSA pneumonia complicated by pneumothorax and reduced pulmonary function. Although the patient was treated with drainage of the pleural cavity and nonsurgical pleurodesis, the pneumothorax could not be managed successfully. The patient underwent successful surgical treatment of the pneumothorax on 105 days after onset. The following factors must be considered in the surgical treatment of pneumothrax with reduced pulmonary function in patients with MRSA pneumonia: 1) When there is massive air leakage, adequate doses of VCM should be administered to prevent pyothorax, 2) when conservative treatment fails and surgical treatment becomes necessary, the operation should be instituted only when MRSA has been completely or almost completely eradicated so as to prevent the occurrence of postsurgical pyothorax, and 3) surgical intervention should be limited to what is necessary to repair the site of ruptured bulla; care should be exercised to preserve as much lung parenchyma as possible and to shorten the operation time.

Aged↗

PubMed1995

[Cisplatin, 5-fluorouracil and leucovorin combination chemotherapy-added radiation therapy for advanced esophageal cancer--a case report].

Cisplatin, 5-fluorouracil and leucovorin combination chemotherapy added radiation therapy was performed for the treatment of 62-year-old male patient with advanced esophageal cancer who had liver cirrlosis. After the treatment, esophageal lesion disappeared. Only minimal side effect occurred during the treatment. Biochemical modulation chemotherapy combined with radiation therapy is useful for advanced esophageal cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1995

[A case of primary mediastinal teratocarcinoma in a young girl].

Primary malignant germ cell tumors of the mediastinum are rare neoplasm, almost always occurring in young adult males. This report described embryonal carcinoma in a 13-year-old girl. The patient was checked up at chest X-ray examination of middle-school pupils on June 1989, and was referred to us because of rapid enlargement of the shadow on October 1989. Chest rentogenograms on admission showed a large mass at the anterior mediastinum, and MRI also revealed a multicystic one extending to the right hemithorax and pressing the superior vena cava and the right atrium. Her serum AFP level was high at 211.1 ng/ml. At operation, on November 6, 1989, a large tumor (110 x 95 x 75 mm) was removed completely through median sternotomy. Histological study of the lesion revealed a wide spread of cystic mature teratoma containing some foci of embryonal carcinoma. Positive immunochemical reaction indicated the presence of AFP in these carcinoma cells. She was treated with 13 courses of anti-cancer chemotherapy by various combinations of CDDP, THP-ADR, VP-16, VCR, ACD, CPM, CBDCA, for one postoperative year. She showed clinical improvement and has continued to be free from recurrence now at 52 months after surgery.

Adolescent↗

PubMed1995

[A case of metachronous primary cancer of the lung, rectum and trachea].

We reported a metachronous primary triple cancer of lung, rectum and trachea. Patient was a 64-year-old male, who was admitted with a episode of bloody sputum. A chest X-ray and rentogen tomogram showed a irregularity and narrowing of the upper trachea. Transbronchoscopic biopsy specimen showed squamous cell carcinoma. December '92, trachea was resected in the length of five cartilages and end-to-end anastomosis was performed. Microscopic examination demonstrated a moderately differentiated squamous cell carcinoma with mediastinal lymph node metastasis. Therefore, he received a course of 30 Gy of radiation to the upper mediastinum after surgery. Three years before the tracheal resection, he had undergone left pneumonectomy for moderately differentiated squamous cell carcinoma of the lung. Nineteen months after the pulmonary resection, he had undergone low anterior resection of the colon for the rectum carcinoma.

Adenocarcinoma↗

PubMed1995

[Experiences of the approaches to heart for a patient with a tracheostoma].

The performance of open heart surgery in a patient with a tracheostoma can present difficult problems, including postoperative mediastinitis and inadequate operative exposure. Recently, we experienced two cases in which tracheostomy had been done preoperatively due to heart failure and reported the satisfactory results in this paper. Case 1; A 59-year-old woman who had mitral stenosis and massive regurgitation received mitral valve replacement and left atrial raphy. The approach to heart was performed in according to the following. A transverse submammary skin incision was made from right anterior axillar line to left mammary line and then a bilateral thoracotomy was made at the fourth intercostal space. Case 2; A 73-year-old man who had old myocardial infarction and postinfarction angina received coronary artery bypassgrafting to right coronary artery and left anterior descending branch, using saphenous vein grafts. A skin incision was placed at the second intercostal space in the fashion of "collar skin incision" and then made from the center of collar skin incision to the xiphoid process. The sternum was transected at the second intercostal space and divided longitudinally to the xiphoid process. These two approaches provided the adequate operative field. The cannulation of the ascending aorta, the superior vena cava and the inferior vena cava presented no difficulty and the operative procedure could be performed easily in a routine manner. We think that in a case of open heart surgery of a patient with a tracheostoma the approach in which the skin incision is distant from the area of a tracheostoma and no dissection near a tracheostoma is necessary have to be selected in order to decrease the risk of postoperative wound infection and mediastinitis.

Aged↗

PubMed1994

A modified invasion-3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay for quantitating tumor cell invasion.

Reconstituted basement membrane matrix (Matrigel) has been utilized for in vitro assay of tumor cell invasion in recent years. In the conventional chamber for the invasion assay, however, a large number of cells passed easily through the center of the Matrigel-coated filter because the Matrigel layer could not be completely uniform by the meniscus formation. To prevent the meniscus phenomenon of the Matrigel layer, we devised a water-repellent treatment of the inside wall of the assay chamber with paraffin. Consequently, very few erythrocytes passed through the Matrigel-coated filter of this modified chamber with the erythrocyte assay, which was used to demonstrate the evenness and uniformity of the Matrigel layer on the filter. For quantitating a small number of cells which invaded through the Matrigel-coated filter by the invasion assay, a tetrazolium-based colorimetric 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assay was used. The invasive abilities of the eight different cells were determined by this invasion-3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium+ ++ bromide assay using the modified chamber with a filter coated with 70 microliters of the 0.2-mg/ml Matrigel. After 72 h of incubation, the malignant cell lines significantly exceeded the normal cell lines in the percentage of invasion (P < 0.01). Therefore, the modified invasion-3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium+ ++ bromide assay provides a simple, easily reproducible in vitro assay for quantitating tumor cell invasion.

Animals↗

PubMed1994

Morphometry of sinusoids and portal hypertension in non-alcoholic cirrhosis.

To examine whether structural changes in hepatocytes and/or sinusoidal areas contribute to the portal hypertensive state in non-alcoholic cirrhosis, a new method of morphometric analysis using a computer-aided color image analyzer was performed in 16 patients with non-alcoholic cirrhosis, which allowed quantitative evaluation of various morphometric parameters of sinusoids and hepatocytes. The sinusoidal pressure gradient was estimated theoretically with these and clearance parameters using Poiseulle's equation and compared with the hepatic venous pressure gradient measure by hepatic vein cannulation. A significant relationship was found between the hepatic venous pressure gradient and sinusoidal volumetric ratio (r = -0.598, p < 0.05), but not between mean hepatocyte volume and sinusoidal volumetric ratio (r = 0.416, NS), or the hepatic venous pressure gradient (r = 0.371, NS). The estimated sinusoidal pressure gradient showed a significant relationship with the hepatic venous pressure gradient (r = 0.637, p < 0.01). However, the absolute values of the former were much lower than those of the latter. Therefore, in non-alcoholic cirrhosis, although sinusoidal stenosis not caused by hepatocyte swelling may lead to increased vascular resistance, other factors must also play a significant role.

Aged↗

PubMed1994

A simple and rapid fluorometric determination method of alpha 1-acid glycoprotein in serum using quinaldine red.

We examined different fluorescent probes suitable for fluorometric determination of alpha 1-acid glycoprotein (AGP) in serum. Quinaldine red (QR) was shown to bind strongly and selectively to AGP. Taking advantage of the enhanced fluorescence of QR in the presence of AGP, we developed a direct method for the determination of serum AGP without removal of other serum proteins such as albumin. AGP concentrations in serum of healthy volunteers and patients correlated well with results from the conventional single radial immunodiffusion (SRID) method (r = 0.93, slope = 1). The newly developed method is faster and has a larger analytical concentration range than the SRID method. This method can also be used to determine AGP in serum of experimental animals, and it can serve to monitor AGP serum concentrations for pharmacokinetic evaluation of basic drugs.

Adult↗

PubMed1994

Gliomas of the conus medullaris.

Six patients with histologically verified gliomas of the conus medullaris (two astrocytomas, two ependymomas, two myxopapillary ependymomas) were diagnosed and studied. There were four men and two women ranging in age from 23 to 47 years. Predominant initial symptoms were back pain (four cases) and leg weakness (two cases). The most common findings on admission were flaccid paparesis with impaired sensation and bladder dysfunction. Postoperative MR images with more than 95% removal of a tumour were defined as 'subtotal removal' (noted in two of six cases), and less than 95% as 'partial removal' (four of six cases). All patients had postoperative radiotherapy, and the two patients with an astrocytoma underwent chemotherapy. During the follow up period ranging from 2 to 7 years, there was no tumour recurrence or regrowth on MR images except in a patient with a malignant astrocytoma, who indeed died from intracranial dissemination 2 years after surgery. Adjuvant therapy following the excision of a spinal glioma is also discussed.

Adult↗

PubMed1994

Effective induction of human NK cells with OK-432 and further augmentation of their cytolytic function by rIL-2.

Low concentrations of exogenously added recombinant interleukin 2 (rIL-2) were able to augment OK-432-induced natural killer (NK) cell activity. This kind of augmenting effect depended on the dose of rIL-2 and manifested itself only in PBMC stimulated with OK-432 (OK-MC) followed by rIL-2; augmentation did not happen in the reverse order. The existence of CD16+/CD25+ (IL-2 receptor positive; IL-2R+) and CD57+/CD25+ double positive cells which possess NK cell surface markers in OK-MC markedly increased in a long-term culture (12 days). A strong positive correlation was observed between the IL-2-dependent augmentation of NK activity and the quantitative changes in cell populations that possessed NK cell phenotypes. Treatment of the day-12-OK-MC with monoclonal anti-CD56 antibody plus complement could almost completely abrogate the augmented NK cytotoxicity. Furthermore, this augmenting effect was detectable within 4 hr after addition of rIL-2 at single cell level, suggesting that the effect did not require NK cell's DNA synthesis. Thus it was suggested that OK-432 could promote and upregulate the expression of IL-2 receptor (CD25) on CD56+ NK cell populations. Moreover, it was considered that the interaction of low concentration rIL-2 with IL-2 receptors on OK-432-activated NK cells could augment their lytic function.

Antigens, CD↗

PubMed1994

Birth injury as a causative factor of syringomyelia with Chiari type I deformity.

The epidemiology of syringomyelia with Chiari type I deformity was investigated with particular reference to perinatal problems. All subjects in our study were born by vaginal delivery and had a high incidence of perinatal accidents (abnormal presentations, birth injuries, and neonatal asphyxia). This study suggests that these may be strong causative factors for syringomyelia associated with Chiari type I deformity.

Adolescent↗

PubMed1994

Posttraumatic syringomyelia: its characteristic magnetic resonance imaging findings and surgical management.

Posttraumatic syringomyelia should be considered in any patient showing a delayed neurological deterioration after spinal cord injury. The purpose of this article is to assess the posttraumatic syringomyelia on magnetic resonance images and to evaluate the results of its surgical treatment. Fourteen patients with posttraumatic syringomyelia were studied. There were 10 men and 4 women ranging in age from 25 to 67 years. Eleven patients with syringomyelia were symptomatic, and the three others were asymptomatic. The periods from spinal cord injury to onset of symptoms due to syringomyelia ranged from 3 to 33 years with a mean of 14 years. On magnetic resonance images, the mean length of the syrinx was 14 vertebral levels and ranged from 3 to 20 levels. At the rostral part of the injured cord, the syrinx was located off center. In contrast, at the caudal part of the injury, the syrinx was markedly large in size and its location was central. In 6 of 13 patients, the syringes extended into the medulla oblongata. Eleven symptomatic patients underwent surgical treatments: a syringosubarachnoid shunt was done in six patients, a syringoperitoneal shunt was done in four, and a ventriculoperitoneal shunt was carried out in one. Shunt malfunction was encountered in three of the four syringoperitoneal shunts and in the one ventriculoperitoneal shunt. Final neurological outcomes were satisfactory in all 11 patients who underwent surgery. Motor function improved in eight of nine patients, sensory disturbance improved in five of five patients, and relief of local pain or numbness was obtained in four of four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Validity of the values of maximal oxygen intake for women recommended in the 'Quantity of exercise for developing health' by Ministry of Health and Welfare].

The purpose of this study was to examine the value of maximal oxygen intake per kilogram body weight (VO2max/wt) recommended for women between 20 and 29 years of age by the Ministry of Public Welfare. The subjects were 199 female college students, who were not in the habit of drinking and smoking. Results obtained were as follows: After controlling the effects of age and percent body fat (%fat), VO2max/wt showed a significant correlations with %fat, high-density lipoprotein cholesterol and systolic blood pressure. The values of VO2max/wt corresponding to borderline values of these CHD risk factors ranged from 27.6 to 29.5ml/kg.min. The highest value of VO2max/wt was very close to the value recommended for women older than 60 years of age by the Ministry of Public Welfare. The subjects were then divided into 4 groups; at above and below the value of VO2max/wt (35ml/kg.min) recommended for women between 20 and 29 years of age, and at above and below the value of VO2max/wt (31ml/kg.min) recommended for women older than 60 years of age by the Ministry of Public Welfare. There were no significant differences among 4 groups in occurrence of abnormal values in CHD risk factors. The results of this study support the validity of the value of VO2max/wt (31ml/kg.min) recommended for women older than 60 years of age by the Ministry of Public Welfare. However, it seems that it is not necessary to recommend the value of VO2max/wt (35ml/kg.min) for women between 20 and 29 years of age, who were not in the habit of drinking and smoking.

Adult↗