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Biomedical subjects

T Maehara

Publications and source records attributed to T Maehara.

At least 127 records · Page 7Linked to original sources
PubMed1993

[A case of mitral regurgitation treated by combined superior transseptal approach and electrophysiological examination of the sinus node function].

A 67-year-old man with mitral regurgitation underwent mitral valvoplasty and annuloplasty successfully. Combined superior transseptal approach was adopted to expose the mitral valve, because the left atrium was small. The exposure of the mitral valve was excellent. But this approach cannot avoid damaging the sinus node artery, so that why the sinus node function was examined electrophysiologically before and after the operation. Sino-atrial conduction time (SACT) and corrected sinus node recovery time (CSRT) were measured as the indices of the sinus node function. Both SNCT and CSRT after the operation was within normal range. As far as this case, combined superior transseptal approach, which gave good exposure of the mitral valve but needed to cut the sinus node artery, did not deteriorate the sinus node function.

Aged↗
PubMed1992

Key roles of nitric oxide and cyclic GMP in nonadrenergic and noncholinergic inhibition in rat ileum.

Nonadrenergic and noncholinergic (NANC) inhibitory responses in circular and longitudinal muscles of the rat ileum were studied separately in vitro. Localized distension with a small balloon caused relaxation of the circular muscle on the anal side of the distended region. Nitro-arginine inhibited the relaxation and L-arginine counteracted the effect of nitro-arginine. Treatment of the preparation with superoxide dismutase (SOD) and methylene blue resulted in enhancement and inhibition, respectively, of the relaxation induced by distension. Nitric oxide caused relaxation of the circular muscle in a dose-dependent manner. 8-Bromo cyclic GMP (cGMP) caused relaxation of the circular muscle. Electrical transmural stimulation caused relaxation followed by a rebound contraction of the longitudinal muscle. Nitro-arginine inhibited the relaxation and L-arginine counteracted this inhibition. Similar results to those in the circular muscle were obtained in the longitudinal muscle with SOD, methylene blue, nitric oxide and 8-bromo cGMP. Electrical field stimulation increased the cGMP content of the longitudinal muscle preparation. Nitric oxide also increased the cGMP content of smooth muscle cells obtained from circular and longitudinal muscles of rat ileum. Preincubation of smooth muscle cells with methylene blue inhibited the effect of nitric oxide on the cGMP content. These results suggest a key role of cGMP in NANC inhibitory responses in rat ileum. The factors mediating the responses are discussed.

Animals↗
PubMed1992

Ki-1-positive large-cell anaplastic lymphoma with protean manifestations including central nervous system involvement.

A 26-year-old female with Ki-1-positive large-cell anaplastic lymphoma is reported. The neoplastic cells were phenotypically and genotypically of T cell origin. Initially, neoplastic cells invaded the skin and lymph nodes, and then invaded the sternal and vertebral bones, ribs and the iliopsoas muscle. Central nervous system (CNS) involvement with paraplegia, large tumor mass formation in her breast and pleural infiltration ensued in succession. This case illustrates the protean manifestations of Ki-1-positive large cell anaplastic lymphoma complicated with CNS involvement.

Adult↗
PubMed1992

[Expression of epidermal growth factor receptor in adult human airway epithelium--application of AMeX method].

To elucidate the role of epidermal growth factor (EGF) in the maintenance and repair of airway epithelial cells in adult humans, we investigated immunohistochemically whether EGF receptor (EGFR) is expressed in these cells. In the present study, we employed the AMeX method (Sato et al., 1986) for tissue preparation. We first examined the expression of EGFR in peripheral lung tissue and bronchial tissue obtained at surgery from thirteen adult patients with lung carcinoma. The results showed that there was no positive staining for EGFR in the bronchial surface epithelium, bronchial glandular cells, bronchiolar epithelium or alveolar lining cells. There was also no expression of EGFR in cells comprising areas of basal cell hyperplasia and epidermoid metaplasia in the bronchus, or alveolar cell hyperplasia and columnar cell metaplasia in fibrotic lung tissue. Second, we examined the expression of EGFR in regenerating distal airway epithelial cells, which were experimentally produced by xenotransplantation of human lung tissue into the subcutaneous tissue of nude mice. There was also no expression of EGFR at any stage of regeneration from one week through six weeks after the transplantation. It is concluded that EGFR is not expressed, at least at an immunohistochemically detectable level, by airway epithelial cells of adult humans, not only in the quiescent state but also under conditions in which epithelial cells are stimulated to replicate. Thus, it appears unlikely that the EGF/EGFR system plays an important role in either maintenance or repair of airway epithelial cells in adult humans.

Adult↗
PubMed1992

[A surgically treated case of acute pulmonary embolism owing to deep vein thrombosis of the leg mainly caused by uterine myoma].

A 49-year-old woman with deep vein thrombosis of the left leg suddenly complained of slight dyspnea during her hospitalization. Enhanced chest CT and pulmonary arterial DSA revealed pulmonary emboli, while phlebography of the left leg and lower abdominal CT showed a uterine myoma compressing the left external iliac vein, which was regarded as a chief cause of deep vein thrombosis of the left leg. The patient became dyspneic severely with a rapid increase of pulmonary arterial pressure and a decrease of arterial oxygen pressure. Therefore, pulmonary embolectomy and deep vein thrombectomy of the left leg and pelvis was performed using a cardiopulmonary bypass. Hysterectomy was also performed after weaning the bypass. The postoperative course was uneventful without recurrence of pulmonary embolism. This was a very rare case of pulmonary embolism, because, as far as we investigated, no literature has reported deep vein thrombosis of the leg caused by uterine myoma. We emphasize the availability of the enhanced CT for diagnosis of pulmonary embolism.

Acute Disease↗
PubMed1991

Perioperative monitoring of total body water by bio-electrical impedance in children undergoing open heart surgery.

UNLABELLED: Knowledge of the changes in total body water (TBW) following cardiac surgery (OHS) in children would be of value in fluid therapy and in researching the causes and management of capillary leak. We have validated a bioelectrical impedance technique (BEI) for non-invasive estimation of TBW in children after OHS. We report the use of this method in a longitudinal study. Twenty patients (mean age 4.7 years +/- 3.5 (SD), mean weight (WT) 16.2 kg +/- 1 kg) undergoing a variety of complex OHS procedures were studied from 1 day preoperatively to 4 days postoperatively. Anaesthetic and basic bypass (CPB) techniques were uniform. Six patients underwent CPB at less than 20 degrees C, 10 at 20 degrees - 25 degrees C and 4 at 26 degrees - 33 degrees C. TBW (BEI), core (ctemp) and peripheral (ptemp) temperatures and fluid balance (TFB) were recorded at frequent intervals. TBW (by BEI) rose (P less than 0.001) following CPB in all patients from 62% +/- 9% (SD) body weight preoperatively to 73% +/- 13% in the ICU (an increase of 11% +/- 5%). TBW remained significantly elevated until the 3rd postoperative day. Multivariate analysis (MVA) confirmed that TBW was significantly related to TFB, but not to ctemp or ptemp. MVA also revealed smaller patient size (height and weight), younger age and longer CPB time as incremental risk factors for the rise in TBW. CONCLUSIONS: (1) BEI permits the non-invasive study of TBW in children after OHS, when TBW variation may be considerable. (2) The smaller the child and the longer the CPB, the greater the rise in TBW. (3) The technique should be a valuable tool in researching the major water fluxes associated with CPB in children.

Body Composition↗
PubMed1991

[A case of T cell lymphoma of the lung].

A 70-year-old woman complained of cough, sputum and fever. Chest roentgenogram showed a mass-like lesion with pleural effusion in the left thorax. Bronchoscopy revealed a polypoid lesion at the orifice of left B10 and mucosal swelling of the left lower lobe bronchi. The biopsied material of the polypoid lesion was diagnosed as malignant lymphoma (diffuse small cell type by LSG classification) and the immunohistochemical examination showed monoclonal proliferation of T lymphocytes. The atypical lymphocytes which were positive for T lymphocyte surface marker were detected in the pleural effusion. There was no evidence of metastasis in any part of the body under clinical examinations, and the lung was thought to be a primary site of the lymphoma. The doubling time of tumor was estimated to be 134 days. Four-drug combination chemotherapy resulted in a marked decrease of the tumor size. Immunohistochemical study to determine the subpopulation of lymphoma cells are required for diagnosis of pulmonary lymphoma, because the biological characters of T cell lymphoma might differ from those of B cell lymphoma.

Aged↗
PubMed1991

[A case report of controlled aortic root reperfusion (CARP) following global myocardial ischemia during surgery for severe mitral stenosis with tricuspid regurgitation].

The use of controlled aortic root reperfusion (CARP) as additional myocardial protection in cardiac surgery has been employed at University of Alabama at Birmingham Since 1986. This technique has been applied to a patient in Japan undergoing mitral valve replacement and tricuspid annuloplasty and favorable results were obtained. The CARP method consists of two consecutive procedures following global myocardial ischemia, that is, terminal warm blood cardioplegic reperfusion and selective controlled coronary perfusion. When the repair was almost completed, the CARP technique was initiated with warm blood (37 degrees C) from an oxygenator, and the initial phase was hyperkalemic (K+ 20 mEq/1, 3 min). [Terminal warm blood cardioplegic reperfusion] This was followed by normokalemic warm blood (without interruption) from the pump oxygenator infused through a cardioplegic needle into the isolated aortic root with the aortic cross-clamp still in place (10 to 20 min). [Selective controlled coronary perfusion] Terminal warm blood cardioplegic reperfusion induced electromechanical quiescence initially which allowed rapid repletion of adenosine triphosphate and improved cardiac function. Selective controlled coronary perfusion with normokalemic warm blood permits necessary and sufficient coronary blood flow following global ischemia even when systemic arterial pressure fell and coronary vascular resistance rose. On considering these two points, we consider that the CARP technique offers excellent myocardial protection in accelerating the recovery of myocardial function following global ischemic damage. The CARP method offers useful assistance in cardiac surgery particularly for patients who have abnormal preoperative cardiac function and who have experienced long periods of global myocardial ischemia.

Aorta↗
PubMed1990

[Clinical usefulness of 67Ga-citrate scintigraphy combined early image in malignant lymphoma--detection of abdominal lesions].

In order to improve the diagnostic accuracy in detecting abdominal lesions of malignant lymphoma, we studied prospectively the usefulness of 67Ga-citrate scintigraphy combined 5 to 6-hour early image with conventional 72-hour delayed image after injection. During the period from July 1986 to September 1988, total 41 67Ga-citrate scintigrams performed on 28 patients with malignant lymphoma (3 Hodgkin's disease, 25 non-Hodgkin lymphoma) were evaluated between early and delayed image regarding to such points as follows; 1) the physiologic bowel uptake of 67Ga-citrate, 2) detection of abdominal lesions indicated by other diagnostic modalities involving computed tomography, lymphography and ultrasonography. Following results were obtained: 1) Prominent bowel uptake of 67Ga-citrate thought to be difficult to interpret the scintigram was observed in only 1 of 41 (2%) on early image versus 13 of 41 (32%) on delayed image. 2) Known lesion sites were detected in 24 of 31 (77%) on early image versus 21 of 31 (68%) on delayed image, resulting in 26 of 31 (84%) in combination with both images. 3) There were 2 false-positive and 5 false-negative lesions. Two false-positive lesions on early image were explained by physiologic hepatic uptake with ill-defined outline and bladder uptake. On the other hand, all of 5 lesions on delayed image were explained by prominent bowel uptake. 4) Two patients were revealed higher splenic uptake comparing with hepatic uptake on both images, later proved to be diffuse splenic involvement without evidence of lesions on other diagnostic modalities. 5) The lesions less than 2 cm in diameter could not be detected in both images.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Neoplasms↗
PubMed1990

Unusually early recoarctation after extended end-to-end anastomosis in a neonate.

A seven-day-old neonate with aortic coarctation and hypoplastic aortic arch underwent extended end-to-end repair with no residual gradient. Eleven hours after repair, femoral pulses were not palpable and recoarctation was confirmed by echocardiography. After failure of prostaglandin E2 infusion, a radically extended end-to-end anastomosis was performed eight days after initial repair. No recoarctation was evident 10 months after the second repair. The unusually early recoarctation was presumably due to residual and active duct tissue in the repair margins.

Anastomosis, Surgical↗
PubMed1990

Glycidyl methacrylate-styrene copolymer latex particles for immunologic agglutination tests.

New latex particles for immunologic agglutination reaction were prepared by a seeded polymerization technique for the emulsifier-free copolymerization of styrene and glycidyl methacrylate. The surface of the latex particles was presumed to be dotted with hydrophilic domains, giving stability to the particles. The remaining areas, to which many antigens or antibodies were strongly adsorbed, were hydrophobic. Various groups of the glycidyl methacrylate-styrene latex particles were coated with human immunoglobulin G, and immunologic agglutinating potencies were compared by the box-titration method. Immunologic reactivities of the latex particles decreased with an increase of glycidyl methacrylate content at concentrations of 1 mol% or higher. Latex particles containing 0.5 to 0.75 mol% GMA caused strong immunologic agglutination besides showing good stability, indicating the availability of these latex particles. Glycidyl methacrylate-free polystyrene latex particles caused non-specific agglutination, while the immunologic agglutinating ability of glycidyl methacrylate-styrene latex particles, prepared by the unseeded polymerization technique was weak.

Acrylates↗
PubMed1990

[A study on reduction rate of tumor volume by irradiation in germinoma, malignant lymphoma, and medulloblastoma].

A relationship between radiation dose and reduction rate of tumor volume was studied in 10 patients with germinoma, nine with malignant lymphoma, and seven with medulloblastoma, in order to evaluate the effect of irradiation on these tumors. Germinomas showed either mono- or biphasic reduction of the volume with increased radiation dose in semi-logarithmic expression, irrespective of their size. All patients are well without relapse except for one that was lost because of transfer. The reduction rate of tumor volume was slightly less in malignant lymphomas and medulloblastomas than that in germinomas and the former two showed less uniformity of response to irradiation according to each case. Malignant lymphomas tended to regrow during irradiation period or early after the period and the effect of irradiation seemed to be related to the size of the tumor. Medulloblastomas did not completely disappeared during irradiation period, but delayed effect of irradiation was recognized after the period.

Adolescent↗
PubMed1990

[Basic and clinical studies on a new method for detecting anti-Mycoplasma pneumoniae antibody, using high density particles].

We developed a new method for detecting anti-Mycoplasma pneumoniae antibody, using high density particles (HDP). We characterized the HDP, and also studied the clinical applicability of the HDP agglutination method (HDPA). HDP were uniform, spherical particles, having a specific gravity of 2.0 and a mean particle volume of 18 fl. Adsorption of IgG by HDP was approximately 2 times that by polystyrene latex. The sensitized antigen to the HDP, extracted from the Mycoplasma pneumoniae (Mac strain) bound specifically to the anti-Mycoplasma pneumoniae antibody. With HDPA, the antibody was determined within 30 minutes, which was more rapid than with other routine methods such as complement fixation test, passive hemagglutination test and particle agglutination test (PA). HDPA showed excellent correlation with PA. However, the titers with HDPA were generally 2 to 5 tubes higher than that with PA. A follow-up study on 7 cases of mycoplasma pneumonia revealed remarkably high titers of anti-Mycoplasma pneumoniae antibodies in the acute phase of mycoplasma pneumonia by HDPA, compared to that by PA. HDPA is highly sensitive and specific test for detection of anti-Mycoplasma pneumoniae antibody, and useful for rapid diagnosis of mycoplasma pneumonia.

Agglutination Tests↗
PubMed1990

[Intrathoracic pacemaker implantation in children].

In order to minimize the complications, we introduced the intrathoracic implantation method since 1976. Until 1988, 12 children underwent this method. A pacemaker generator was exchanged in 8 patients, 12 times, because of battery exhaust. Compared with the conventional method (abdominal wall implantation), the complications such as electrode fracture, which was related to the implantation sites, were reduced. Furthermore it was very useful from the cosmetic viewpoint. Although an exchange of generator was very easily done at the first time, it was very difficult at the second time, due to rib fusion accompanying with children's growth.

Adolescent↗
PubMed1990

A computed tomography study on formation, propagation, and resolution of edema fluid in metastatic brain tumors.

Propagation of contrast medium, which extravasated from small metastatic brain tumor, was imaged via CT. By maintaining a constant blood level of the contrast medium by prolonged infusion of 200 ml of 60% meglumine amidtrizoate for 3 hr and thus maintaining a constant passage of contrast labeled edema fluid into the peritumoral extracellular space, the spread of the newly formed edema fluid can be imaged by repeated CTs as a gradually expanding peritumoral circular enhancement into the neighboring white matter. Four patients with small metastatic brain tumor were investigated. CT scans were taken at identical levels 1.5, 3, 6, 9, and 12 hr after start of contrast infusion. After 4 to 7 days of dexamethasone treatment (0.15-0.25 mg/kg/day), the examination was repeated. The area of the expanding circular enhancement was planimetrically measured. From these values, the increase in radius per hour, respectively, in volume per hour were calculated assuming a spherical geometry. These data enabled a determination of the formation rate of edema fluid, of the speed of edema propagation, and of the resolution rate of edema fluid during tissue passage. The formation rate of edema fluid amounted to 0.6 to 3.2 ml/hr depending on tumor diameter and was reduced by about 30% after dexamethasone treatment. Edema fluid traveled 4.8 mm during the first 180 min and 1.9 mm during the consecutive 90 min. The resolution rate of edema fluid during tissue passage amounted to 0.05 ml/hr/cm3 white matter before dexamethasone treatment.

Brain Edema↗