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Biomedical subjects

T Miki

Publications and source records attributed to T Miki.

At least 685 records · Page 38Linked to original sources
PubMed1992

[Augmentation of left ventricular slow filling in hypertrophic cardiomyopathy].

To investigate the significance of augmentation of left ventricular slow filling, trans-mitral flow (TMF) was echocardiographically observed through pulsed Doppler method in 116 patients with hypertrophic cardiomyopathy (HCM), 74 with dilated cardiomyopathy (DCM), 27 with mitral regurgitation (MR), 86 with old myocardial infarction (OMI) and 80 normal controls (C). The slow filling-wave (SFW) in TMF was defined as the filling wave with obvious peak velocity during slow filling phase. The peak velocities (E, A, S) of the early filling, the atrial contraction and the slow filling waves were measured. The SFW was divided into two patterns according to the S and E ratio: large SFW (S/E greater than or equal to 1/2) and small SFW (S/E less than 1/2). 1) The small SFW was more frequently, but not significantly, observed patients with MR (37%) than in normal subjects (18%), patients with HCM (10%), DCM (4%) and OMI (7%). However large SFW was observed in 16 patients (14%) with HCM, but not in normal subjects and patients with other cardiac diseases excluding one patient with DCM. 2) In normal subjects and patients with DCM, OMI and MR, those with small SFW had larger E and smaller A/E than those without small SFW. However in patients with HCM, there was no difference in these indices (E and A/E) according to whether the patients were with or without SFW. 3) In HCM, patients with large SFW had significantly smaller E and significantly larger isovolumic relaxation time than those without SFW. Thus, appearance of the large slow filling wave, which might be caused by abnormal relaxation of the left ventricle, was frequently observed in patients with HCM.

Adult↗
PubMed1992

Analysis of the apolipoprotein B3' hypervariable region in patients with essential hypertension.

1. The typing of the apolipoprotein B 3' hypervariable region was investigated in hypertensive and normotensive subjects using rapid typing of a variable number of tandemly repeated short DNA sequences (VNTR) by the polymerase chain reaction. 2. In the DNA samples of 89 normotensive and 99 hypertensive patients, 13 different-sized alleles were detected. The most frequent allele has 35 repeat units in both groups with frequencies of 0.624 and 0.596 in normotensive and hypertensive patients, respectively. Frequency distribution of 13 alleles was similar in both groups. 3. These results demonstrate no association between the apolipoprotein B gene polymorphism and essential hypertension.

Aged↗
PubMed1992

Activation of kinins on myocardial ischemia.

In experimental ischemic dog heart with coronary-constriction, no increase of coronary blood flow, Max dP/dt or MVO2 with no change of kinin in arterial blood were exhibited. Following sympathetic nerve stimulation, remarkable increases of kinin in coronary sinus blood were observed with a significant elevation of left ventricular end-diastolic pressure and an augmented production of lactate from the heart as well as an ischemic change of ECG-ST. Infusion of kinin into the left main coronary artery resulted in no change in the mean systemic blood pressure, coronary blood flow, coronary vascular resistance, cardiac function, myocardial metabolism or ECG-ST in the control and coronary-constricted groups. These data suggest that kinin was released significantly from the ischemic heart, however, such a level of kinin has no significant effect on coronary circulation or myocardial metabolism. In ischemia-reperfusion rabbit hearts, no significant influence of the ACE inhibitors, captopril and ramiprilat, were observed. Species differences may be responsible for the beneficial role of ACE inhibitors in the limitation of infarct size in the dog hearts, possessing collateral flow, that are not seen in the rabbit heart with poor collateral flow.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

[Dye leakage in indocyanine green fundus angiography of a laser photocoagulated lesion].

Argon green laser photocoagulation was performed on adult pigmented rabbit eyes at various intensities (parameters:500 microns spot size, 0.2 sec. exposure, and 70-, 100-, 150- and 200-mW power levels), and fluorescein and indocyanine green (ICG) angiography was performed within one hour after coagulation. Each coagulum of ICG angiography was hypofluorescent in the early phase and brightly fluorescent in the late phase. The fluorescein and ICG dyes spread from the periphery to the center in the moderate and large coagula. The characteristic finding of ICG angiography was expansion of ICG dye around the coagulum, regardless of the degree of the coagulation. This ICG leakage was intra-choroidal because there was no fluorescein dye leakage around the coagulum. We concluded that the ICG dye leakage shows damage to the choroidal vessels due to laser photocoagulation, and is not related to the barrier function of the retinal pigment epithelium.

Animals↗
PubMed1992

[Clinical experience with the omnicarbon valve prosthesis].

Between January 1985 and March 1990, isolated valve replacements with the Omnicarbon valve were performed in 90 patients aged 34-72 years. There were 53 aortic valve replacements (AVR) and 37 mitral valve replacements (MVR). The cumulative follow-up was 320 patient-year (py) with a mean follow-up of 3.7 +/- 1.4 years. There were 3 operative and hospital mortalities (3.3%), resulting from retrograde aortic dissection during cardiopulmonary bypass, postoperative renal failure, and rupture of infective pseudoaneurysm in ascending aorta. Seven patients died during the late postoperative period, 4 due to valve-related causes. Two of these patients died of prosthetic valve endocarditis (PVE), while the others died of thromboembolism (including valve thrombosis). The overall actuarial survival rate at 6 years was 86.3% (98.8% for AVR, and 82.1% for MVR). There were 2 thromboembolic events (one mesenteric artery thrombosis, and the other valve thrombosis). The linearized incidence of thromboembolism was 0.63%/py. PVE occurred in 3 patients (0.94%/py). One patient (0.31%/py) was found to have a valve dehiscence due to aortitis syndrome. There were no instances of anticoagulant-related hemorrhage, or valve-related hemolysis. The actuarial rate of freedom from valve-related mortality at 6 years was 93.5% (100% for AVR, and 88.1% for MVR). On the basis of a follow-up period of 6 years, good clinical results and a low incidence of valve-related complications can be demonstrated with Omnicarbon valve.

Adult↗
PubMed1992

[Surgical treatment under extracorporeal circulation for renal cell carcinoma with tumor thrombus in inferior vena cava].

Three cases of renal cell carcinoma with tumor thrombus extending into the inferior vena cava are reported. Radical nephrectomy and thrombectomy were performed under extracorporeal circulation in all the cases. The level of tumor thrombus was preoperatively determined by computed tomography, magnetic resonance imaging or venacavography. The tumor thrombus extended into the right atrium in one, and above the hepatic vein in two cases. One patient whose thrombus reached the right atrium died of multiple metastasis of renal cell carcinoma 5 months after operation. Another patient with lung metastasis was given interferon-alpha and is alive 5 months after operation. The other patient is clinically free of disease and in good health 7 years after operation. We believe that extracorporeal circulation allows an opportunity to resect the tumor thrombus in a controlled situation, and makes the operation safer.

Aged↗
PubMed1992

[Spontaneous peripelvic extravasation associated with primary ureteral tumor: a case report].

A case of spontaneous peripelvic extravasation associated with primary ureteral tumor is reported. A 56-year-old woman presented with left flank pain. Excretory urogram and abdominal computed tomographic (CT) scan demonstrated left hydronephrosis with extravasation of contrast materials around the renal pelvis. Retrograde pyelogram showed the filling defect in the left upper ureter. Under diagnosis of ureteral tumor, total nephroureterectomy was performed. Histological findings revealed transitional cell carcinoma. 80 cases of spontaneous peripelvic extravasation in Japan were reviewed and discussed briefly.

Carcinoma, Transitional Cell↗
PubMed1992

[Persistent müllerian duct syndrome with seminoma: report of a case].

A case of persistent Müllerian duct syndrome associated with seminoma is reported. A 22-year-old man was admitted with the chief complaint of left flank colicky pain. Physical examination revealed huge abdominal mass and absence of left intrascrotal contents. Right hydrothorax and left ureteral calculi were pointed out with radiography. The abdominal tumor was reduced by effective chemotherapy. Extirpation confirmed the presence of seminoma and persistent Müllerian duct structure. This case showed left testicular transverse ectopia. In our review of the Japanese literature, 16 cases of transverse testicular ectopia accompanied with testicular tumor are reported.

Adult↗
PubMed1992

[Lymphomatoid granulomatosis (LYG) occurring in a patient with follicular lymphoma during remission].

A 49 years-old man presented with dry cough, low grade fever, and abnormal shadow on a chest X-ray. He had suffered from follicular lymphoma of the liver 5 years previously. He received irradiation therapy in combination with chemotherapy for approximately three years and had been in complete remission. Physical and radiological examination revealed pleural effusion and softly dense masses in the right lung. The laboratory data were within normal limits. He was diagnosed as having lymphomatoid granulomatosis (LYG) by open lung biopsy. The lung lesion was mainly infiltrated with T cells. The patient received prednisolone and the lung lesions disappeared. However, when a lung mass was noted two months later, he started to receive combination chemotherapy consisting of cyclophosphamide, adriamycin, vincristine, and prednisolone every three months. He has not shown relapse of LYG so far. To investigate the association between the preceding follicular lymphoma and subsequent LYG at this time, DNA analysis using the PCR technique was carried out. The LYG lesion did not show a rearranged band for the JH probe, while the paraffin-embedded specimen of the preceding follicular lymphoma had shown rearranged band for the JH band. Southern blot analysis of the LYG lesion, showed no rearrangement for TCR beta, gamma or JH probe. These findings indicate that the LYG was different from the preceding follicular lymphoma in terms of origin. LYG is considered to be induced in the immunosuppressive state due to lymphoma.

Combined Modality Therapy↗
PubMed1992

[Comparative study of anticoagulant management after coronary artery bypass surgery--warfarin versus dipyridamole].

A prospective randomized study was performed in 137 coronary artery bypass surgery cases to determine if the administration of antiplatelet drugs would improve the patency of coronary artery bypass grafts. The warfarin group received warfarin and thrombotest was controlled to 20% or so. The dipyridamole group received both 300 mg of dipyridamole and 250 mg of aspirin orally each day. These two groups were compared for study in grafts patency. Results were analyzed by chi-square. In the warfarin group, 66 patients had three ITA-LAD grafts and 115 saphenous vein grafts (including 4 sequential grafts). In the dipyridamole group, 71 patients underwent 38 ITA grafts and 167 saphenous vein grafts (including 56 sequential grafts). Eighty-eight of the 107 grafts (82%) were patent in the warfarin group, and 190 of 205 grafts (95%) were patent in the dipyridamole group (p less than 0.01). Of the two ITA grafts in the warfarin group, no graft was occluded, a patency of 100%. In the dipyridamole group, 35 of 38 ITA grafts (92%) were patent. In the warfarin group, 86 of 105 saphenous vein grafts (82%) were patent. In the dipyridamole group, 155 of 167 saphenous vein grafts (95%) were patent (p less than 0.01). In the study of grafted coronary vessel, the patency of left anterior descending coronary artery, diagonal branch and right coronary artery was not significant between two groups. In the dipyridamole group, the patency of left circumflex coronary artery was 93%, and that of the warfarin group was 50% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Indocyanine green enhanced photocoagulation in the pigmented rabbit].

We performed histological studies of rabbit eyes after intravenous administration of indocyanine green (ICG) and fundus endophotocoagulation with diode laser at the wavelength of 810 nm. As continuation of our previous experiments in albino rabbits, we used 10 eyes of 5 pigmented rabbits which more simulate human eyes. We created weak photocoagulation spots 5 to 30 seconds after intravenous ICG, 4 mg/kg. Each photocoagulation lasted 0.2 sec and its irradiation power was averaged 170 mW. One hour after photocoagulation, there were no changes in the inner retinal layers. In the choroid, we observed occlusion of the choriocapillaris, destruction or loss of endothelial cells of large choroidal vessels, and stromal edema. One month after photocoagulation, large choroidal vessels had disappeared. Whole choroidal layers were replaced by fibrous scar tissue. The findings seemed to indicate that ICG enhanced photocoagulation effect can be observed in eyes with pigmented retinal pigment epithelium and that irreversible choroidal damages can be induced throughout the whole thickness of the choroid. The observed choroidal damages were less in intensity than those in albino rabbits.

Animals↗
PubMed1992

[Indocyanine green videoangiography of the choroidal circulation in the experimental retinal opacity induced by blunt trauma].

Retinal opacity was experimentally induced by blunt trauma to the rabbit eye and the damage to the choroidal circulation was investigated immediately thereafter by using indocyanine green (ICG) videoangiography. Ten pigmented rabbit eyes were used. In the early phase, the defect of choroidal inflow (10 eyes), the twitch of the choroidal artery (2 eyes) and the reflux of the vortex vein (5 eyes) could be observed dynamically. The defect of choroidal inflow showed its peak around the point where the choroidal arteries branched off from ciliary arteries and disappeared within a few second to over ten seconds. The reflux from the vortex vein seemed to be important as collateral pathway. In the middle phase, several points of ICG leakage were observed around the apex of the delayed area of choroidal circulation (9 eyes). This ICG leakage was intra-choroidal and seemed to be caused by the breakdown of the great vessels at the outer layer of the choroid. This study indicates that ICG videoangiography could observe various choroidal circulatory disturbances following blunt trauma and may be useful in delineating the pathogenesis of retinal opacity.

Animals↗
PubMed1991

Inhibition of intracellular topoisomerase II by antitumor bis(2,6-dioxopiperazine) derivatives: mode of cell growth inhibition distinct from that of cleavable complex-forming type inhibitors.

In the accompanying paper (K. Tanabe, Y. Ikegami, R. Ishida, and T. Andoh, Cancer Res., 51: 4903-4908, 1991), we showed that ICRF-154 and -193, dioxopiperazine derivatives, inhibited the activity of purified topoisomerase II, without formation of a cleavable DNA-protein complex. In order to see whether ICRF-154 and ICRF-193 affect cellular topoisomerase II in situ or not, we examined the effect of these drugs on etoposide (VP-16)-induced, topoisomerase II-mediated DNA breaks in RPMI 8402 cells by alkaline sedimentation analysis. When RPMI 8402 cells were exposed to VP-16 in the presence of ICRF-154 or ICRF-193 for 1 h, VP-16-induced DNA strand breaks were greatly inhibited by both ICRF compounds. In parallel with this observation, VP-16-induced growth inhibition was also reversed by ICRF-193. Exposure of cells to ICRF-154 resulted in a progressive accumulation of cells with 4C DNA content. Although mitotic index did not significantly increase, mitotic abnormalities were seen in cells exposed to ICRF-193 or ICRF-154: all mitotic cells exhibited early mitotic figures with fewer condensed and entangled chromosomes. The most sensitive phase of the cell cycle to ICRF-154 was the G2-M. ICRF-154 did not affect the spindle formation. However, abnormally oriented spindles were observed in drug-treated cells in parallel with the appearance of multinucleated cells. The results suggest that ICRF-154 and -193 inhibit topoisomerase II activity in RPMI 8402 cells, and this effect resulted in the appearance of cells in G2 and early M phase with fewer condensed and entangled chromosomes and of cells with multilobed nuclei.

Cell Cycle↗
PubMed1991

The 717Val----Ile substitution in amyloid precursor protein is associated with familial Alzheimer's disease regardless of ethnic groups.

Alzheimer's disease (AD) is a devastating neurological disorder and the leading cause of dementia among aged individuals. The human amyloid beta protein, which is a cleavage product of amyloid precursor protein (APP), is a major component of the amyloid deposited in the brain of patients with AD. By using PCR direct sequencing of exon 17 (encoding part of the beta protein) of the APP gene, we have found that a Japanese AD patient harbours a C to T substitution, responsible for a valine to isoleucine change at position 717, heterogeneously. The mutation is exactly the same as that found in a Caucasian AD family by Goate et al. (1). Furthermore, the mutation was shown to co-segregate with AD in his family. These results suggest that the Val----Ile change in the APP causes AD, regardless of ethnic background.

Alzheimer Disease↗
PubMed1991

Development of a highly efficient expression cDNA cloning system: application to oncogene isolation.

We developed an expression cDNA cloning system capable of generating high-complexity libraries with unidirectionally inserted cDNA fragments and allowing efficient plasmid rescue. As an application of this system, a cDNA library was constructed from an NIH 3T3 transformant induced by mouse hepatocellular carcinoma DNA. Transfection of NIH 3T3 cells by the library DNA led to the detection of several transformed foci from which identical plasmids with transforming ability could be rescued. Structure and sequence analysis of the cDNA clones revealed that the oncogene was created by recombinational events involving an unknown gene and the mouse homologue of the B-raf protooncogene. Detection of the same genetic rearrangement in independent primary transformants implied that generation of the oncogene occurred within the tumor rather than during DNA transfection or cDNA library construction. The high frequency at which clones were identified and the large sizes of some of the transforming cDNA inserts isolated suggest wide applicability of this mammalian expression cloning system for isolating cDNAs of biologic interest.

Amino Acid Sequence↗
PubMed1991

The retinoblastoma gene functions as a growth and tumor suppressor in human bladder carcinoma cells.

The product of the human retinoblastoma gene (RB) is a nuclear phosphoprotein that is thought to function as a tumor suppressor. Mutations of RB frequently occur in human bladder carcinoma. To investigate the significance of the functional loss of this gene in bladder cancer, an RB expression plasmid (pBARB) under control of the human beta-actin promoter was transfected into the bladder carcinoma cell line HTB9, which lacks RB expression. Marker-selected transfectants that expressed RB protein were identified by immunoblotting and immunohistochemical staining. In selected clones, stable RB expression has persisted over 1 yr under standard culture conditions with 10% serum. However, RB expression caused major alterations of HTB9 growth properties both in vitro and in vivo. RB+ transfectants lacked the ability to form colonies in semi-solid medium, and their growth rate was significantly decreased in 3% serum. In addition, the tumorigenicity of these transfectants was markedly decreased. Tumors that formed in nude mice were much smaller and had a longer latency period but were indistinguishable microscopically from those produced by parental cells. Slower growing tumors were RB+, as measured by nuclear staining of their RB protein and by a normal RB protein pattern on immunoblots. These findings support the concept that the RB gene acts as both a growth and tumor suppressor in bladder cancer cells.

Actins↗
PubMed1991

A broad-spectrum human lung fibroblast-derived mitogen is a variant of hepatocyte growth factor.

A heparin-binding mitogen was isolated from conditioned medium of human embryonic lung fibroblasts. It exhibited broad target-cell specificity whose pattern was distinct from that of any known growth factor. It rapidly stimulated tyrosine phosphorylation of a 145-kDa protein in responsive cells, suggesting that its signaling pathways involved activation of a tyrosine kinase. Purification identified a major polypeptide with an apparent molecular mass of 87 kDa under reducing conditions. Partial amino acid sequence analysis and cDNA cloning revealed that it was a variant of hepatocyte growth factor, a mitogen thought to be specific for hepatic cells and structurally related to plasminogen. Recombinant expression of the cDNA in COS-1 cells established that it encoded the purified growth factor. Its site of synthesis and spectrum of targets imply that this growth factor may play an important role as a paracrine mediator of the proliferation of melanocytes and endothelial cells, as well as cells of epithelial origin.

Amino Acid Sequence↗