Biomedical subjects

N Minato

Publications and source records attributed to N Minato.

At least 55 records · Page 3Linked to original sources

PubMed1996

NK 1+ CD4- CD8- alphabeta T cells in the peritoneal cavity: specific T cell receptor-mediated cytotoxicity and selective IFN-gamma production against B cell leukemia and myeloma cells.

NK1+ double negative (DN) alphabeta T cells were present in the peritoneal exudate cells (PEC) of both normal and athymic B6 mice, accounting for as much as 25% of the total T cells, while their numbers were far less in the PEC of BALB/c and (BALB/c x B6)F1 mice. IL-2-dependent clones established from the DN alphabeta T cell population in the PEC of IL-2 receptor alpha-chain transgenic B6 mice exhibited potent cytotoxicity against a series of B cell lineage leukemias and myelomas, such as CD5+BCL1 and MOPC, without affecting NK-susceptible targets. The cytotoxicity of the clones against BCL1 and MOPC was specifically inhibited by anti-CD3, anti-alphabetaTCR, or anti-relevant Vbeta (Vbeta8) Ab, but not by control Abs, indicating that it was mediated by the specific alphabetaTCR/CD3. Other BALB/c-derived target cells expressing both MHC class I and class II were not affected, and neither Ab against them affected the cytotoxicity, strongly suggesting that the cytotoxicity of NK1+ DN alphabeta T cell clones was independent of the particular MHC Ags. The clones produced IFN-gamma, but little IL-2 or IL-4, in response to anti-CD3 stimulation, to the susceptible, but not resistant, targets, and to IL-12. The clones exhibited TCRalpha (Valpha8) distinct from an invariant TCRalpha (Valpha14) reported to dominate in thymic NK1+ alphabeta T cells. The presence of DN alphabeta T cells with similar functional features in the normal PEC was confirmed by the short term stimulation in vitro. The present results along with other recent reports strongly suggested that, like the mainstream alphabeta T cells, the NK1+ DN alphabeta T cell population consisted of functionally heterogeneous subsets.

Amino Acid Sequence↗

PubMed1996

Surgical treatment for acute aortic arch dissection.

Between March 1983 and December 1993, 24 consecutive patients with acute aortic dissection resulting from a tear located in the aortic arch or at the base of the innominate artery underwent surgical treatment. Before 1988, 11 patients (group 1) underwent either isolated ascending aorta replacement (eight cases) or composite graft replacement (three) by the conventional method. In this group, the hospital mortality rate was 36.4%; two of seven surviving patients required reoperation for aortic arch. After 1989, 13 patients (group 2) underwent either hemiarch replacement (five cases), total arch replacement (three), extended ascending aortic replacement or composite graft replacement with hemiarch replacement (one) under a brief period of circulatory arrest (mean 33.3 min) at a mean(range) rectal temperature of 20.8(18-23) degrees C by open distal anastomosis. The operative mortality rate in group 2 was 15.4%. Ten of 13 surviving patients are free from reoperation (mean follow-up 40 months). In most patients with acute type A dissection in which the tear is located at the proximal aortic arch or at the base of the innominate artery, the use of an open technique during a brief period of hypothermic circulatory arrest is advocated to: (1) perform a more secure distal anastomosis; (2) provide a more accurate assessment and resection of intimal disruption; and (3) avoid further aortic injury from the cross-clamp.

Acute Disease↗

PubMed1996

Developmentally regulated expression of the PD-1 protein on the surface of double-negative (CD4-CD8-) thymocytes.

PD-1, a member of the Ig superfamily, was previously isolated from an apoptosis-induced T cell hybridoma 2B4.11 by subtractive hybridization. Expresson of the PD-1 mRNA is restricted to thymus in adult mice. Using an anti-PD-1 mAb (J43), we examined expression of the PD-1 protein during differentiation of thymocytes in normal adult, fetal and RAG-2(-/-) mice with or without anti-CD3 mAb stimulation. While PD-1 was expressed only on 3-5% of total normal thymocytes, approximately 34% of the CD4(-)CD8(-) double-negative (DN) fraction are PD-1(+) cells with two distinct expression levels (low and high). PD-1(high) thymocytes belonged to TCR gammadelta lineage cells. In the DN compartment of the TCR alphabeta lineage, PD-1 expression started at the low level from the CD44(+)CD25(+) stage and the majority of thymocytes expressed PD-1 at the CD44(-)CD25(-) stage in which the thymocytes express TCR beta chains. The anti-CD3epsilon antibody administration augmented the PD-1 expression as well as the differentiation of the CD44(-)CD25(+) DN cells into the CD44(-)CD25(-) DN stage, not only in normal mice but also in RAG-2-deficient mice. The fraction of the PD-1(low) cells in the CD4(+)CD8(+) double-positive (DP) compartment was very small (<5%) but increased by stimulation with the anti-CD3 antibody, although the total number of DP cells was drastically reduced. The results show that PD-1 expression is specifically induced at the stages preceding clonal selection.

Aging↗

PubMed1996

[A case of infective aortic valve endocarditis with splenic abscess].

A 47-year-old woman was admitted to our hospital with high fever, exertional dyspnea and left flank pain. Echocardiography revealed vegetations attached to the aortic valve and moderate aortic regurgitation. Streptococcus anginosus was identified by blood culture examination. Abdominal CT scan showed a low density area in the spleen. The diagnosis of infective aortic valve endocarditis with splenic abscess was obtained. The splenectomy and the aortic valve replacement were performed simultaneously after the treatment with antibiotics. The postoperative clinical course was uneventful. In the case of infective endocarditis with splenic abscess, the splenectomy concomitant with valve surgery should be performed for removing all of the infected tissues.

Abscess↗

PubMed1996

[A case report of mitral valve plasty for traumatic mitral regurgitation].

A 64-year-old man was admitted to our hospital with a chief complaint of general fatigue on June 24, 1993. He had no history of rheumatic fever but bruised in the chest in September 1990. After that, his systolic murmur was noticed at the apex and echocardiogram showed the posterior chordal rupture of mitral valve. Mitral valve plasty was performed successfully.

Chordae Tendineae↗

PubMed1996

[Regulatory mechanisms of lymphocyte proliferation: roles of Spa-1 gene].

Spa-1 genes is one of the secondary response genes specifically induced to express in the lymphoid cells following the mitogenic stimulations by antigens or mitogenic cytokines. Gene transfection experiments indicate that Spa-1 protein exhibits negative effect on cell growth and induces cell death when ectopically overexpressed. Spa-1 protein is a nuclear protein and suggested to function through the interaction with Ran, so far the only small G protein present in the nuclei, While Spa-1 mRNA is expressed in normal proliferating lymphocytes as well as factor-dependent cell lines, little mRNA is expressed in autonomously growing leukemic lines, suggesting the active repression of Spa-1 transcription in transformed cells. Analysis of this mechanism may provide a new insight into the transformation processes in lymphoid cells.

GTPase-Activating Proteins↗

PubMed1995

Decreases of CD4- and CD8-positive T lymphocytes in retired chromate workers.

To investigate the effects of chromates on the human immune system, we measured total T lymphocytes and their two major subpopulations (CD4+ and CD8+ T lymphocytes) in the peripheral blood of 19 retired male workers who had been exposed to chromate at a chemical plant. The results indicated that both CD4+ and CD8+ T lymphocytes were significantly decreased, resulting in decreases in total T lymphocytes and total lymphocytes.

Adult↗

PubMed1995

Molecular cloning of a novel mitogen-inducible nuclear protein with a Ran GTPase-activating domain that affects cell cycle progression.

We have cloned a novel cDNA (Spa-1) which is little expressed in the quiescent state but induced in the interleukin 2-stimulated cycling state of an interleukin 2-responsive murine lymphoid cell line by differential hybridization. Spa-1 mRNA (3.5 kb) was induced in normal lymphocytes following various types of mitogenic stimulation. In normal organs it is preferentially expressed in both fetal and adult lymphohematopoietic tissues. A Spa-1-encoded protein of 68 kDa is localized mostly in the nucleus. Its N-terminal domain is highly homologous to a human Rap1 GTPase-activating protein (GAP), and a fusion protein of this domain (SpanN) indeed exhibited GAP activity for Rap1/Rsr1 but not for Ras or Rho in vitro. Unlike the human Rap1 GAP, however, SpanN also exhibited GAP activity for Ran, so far the only known Ras-related GTPase in the nucleus. In the presence of serum, stable Spa-1 cDNA transfectants of NIH 3T3 cells (NIH/Spa-1) hardly overexpressed Spa-1 (p68), and they grew as normally as did the parental cells. When NIH/Spa-1 cells were serum starved to be arrested in the G1/G0 phase of the cell cycle, however, they, unlike the control cells, exhibited progressive Spa-1 p68 accumulation, and following the addition of serum they showed cell death resembling mitotic catastrophes of the S phase during cell cycle progression. The results indicate that the novel nuclear protein Spa-1, with a potentially active Ran GAP domain, severely hampers the mitogen-induced cell cycle progression when abnormally and/or prematurely expressed. Functions of the Spa-1 protein and its regulation are discussed in the context of its possible interaction with the Ran/RCC-1 system, which is involved in the coordinated nuclear functions, including cell division.

3T3 Cells↗

PubMed1995

[Horner syndrome due to mediastinal neurinoma--a case report].

Horner syndrome due to mediastinal neurinoma has been reported rare cases so far. We experienced a 55-year-old woman who developed Hornor syndrome due to mediastinal neurinoma and the patient received operation with no major complication. She was admitted to our hospital because of the left shoulder pain and the dilatation of the mediastinum on chest X-ray. She was found to have the left mild ptosis and CT scan showed left upper mediastinal tumor (12 cm in diameter) with tracheal compression. Aortography showed a 8.6 cm tumor stein and lower deviation of aortic arch. The feeding artery was branch of thyrocervical artery. Mediastinal neurinema was found by biopsy. During the operation, we found the origin was the left sympathetic nerve. The post operative course was uneventful however horner syndrome was progressed due to radical resection of the tumor.

Disease Progression↗

PubMed1995

Perioperative coronary artery spasm in modified Bentall's operation for annulo-aortic ectasia in Marfan's syndrome. A case report of perioperative chordal rupture of the mitral valve.

We experienced a rare case of Marfan's syndrome with annulo-aortic ectasia, aortic regurgitation and Prinzmetal's variant angina. In a modified Bentall's operation (button technique), perioperative severe coronary artery spasm occurred in spite of the preventive use of nitroglycerin infusion, which resulted in profound ventricular fibrillation and subsequent chordal rupture of the mitral valve with Sellers IV regurgitation. Use of nicardipine contained in cardioplegia, continuous infusion of nicardipine and nitroglycerin after aortic declamping completely prevented coronary spasm throughout the course of a second surgery for mitral valve replacement. It is worthy to report this case because of rarities such as Marfan's syndrome accompanied by Prinzmetal's variant angina, perioperative coronary artery spasm in modified Bentall's operation, and perioperative chordal rupture of the mitral valve and progression of mitral valve regurgitation. We also stress the efficacy of a new calcium antagonist, nicardipine, to prevent coronary artery spasm during open heart surgery.

Angina Pectoris, Variant↗

PubMed1994

Involvement of 4F2 antigen expressed on the MHC-negative target cells in the recognition of murine CD3+CD4-CD8- alpha beta (V alpha 4/V beta 2) T cells.

T cells of an unique phenotype (CD3+CD4-CD8- alpha beta TCR+) develop in vitro from the hematopoietic progenitors, the majority of which carry homologous alpha beta TCR (V alpha 4J alpha 28/V beta 2D beta 1.1J beta 2.6). In the present study, antigen corresponding to the particular alpha beta TCR was investigated, taking advantage of the fact that growth of T cell hybridomas was arrested by their TCR stimulation. Results indicated that both syngeneic and allogeneic thymocytes, particularly from newborn mice, could specifically inhibit the proliferation of a T cell hybridoma with the V alpha 4/V beta 2 TCR (15H1.2). Proliferation of neither TCR-missing hybridoma subclones nor those with unrelated alpha beta TCRs was affected at all. It was also found that embryonal carcinoma (EC) cells without classical MHC antigens could specifically inhibit the proliferation of 15H1.2 cells. We then raised a mAb, 14.37, against an EC line, OTF9, that could interfere with the ability of them to inhibit the growth of 15H1.2. Pretreatment of 15H1.2 cells with anti-V beta 2 and OTF9 cells with 14.37 mAb respectively completely abrogated the growth inhibition of 15H1.2 by OTF9. The 14.37 antigen was a 120 kDa heterodimer glycoprotein consisting of 85 and 36 kDa proteins. In normal lymphoid tissues, the expression of 14.37 antigen exhibited an apparently inverse relationship with that of class I MHC antigens. Thus, ontogenically it was strongly expressed in fetal and newborn mice, rather rapidly declined thereafter, and remained at very low levels in adult organs. In a given stage, the distribution of 14.37 antigen and class I MHC was rather exclusive to each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Pulmonary hypertension in systemic lupus erythematosus: a report of an autopsied case.

An autopsied case of systemic lupus erythematosus with pulmonary hypertension is reported. A 29-year-old woman with a seven-year history of polyarthralgia, butterfly rash, nephrotic syndrome and Raynaud's phenomenon was admitted because of progressive dyspnea on exertion. Tests for antinuclear antibody, anti-cardiolipin antibody and lupus anticoagulant were positive. Echocardiographic examination revealed right ventricular hypertrophy and a moderate pericardial effusion. Estimated systolic pulmonary arterial pressure was 53 mmHg. Despite treatment with corticosteroids including pulse methylprednisolone therapy, lipo-PGE1 and warfarin, she died of progressive congestive heart failure. Postmortem examination of the pulmonary vasculature revealed findings consistent with plexogenic pulmonary arteriopathy, without evidence of vasculitis, fibrinoid necrosis, or thromboemboli.

Adult↗

PubMed1994

[T cell development and selection in extrathymic environments].

Thymocytes express randomly diversified TCRs by TCR gene rearrangement and those reactive to self antigens are negatively selected while those capable of recognizing antigens in the context of self MHC antigens are positively selected. The selection process in the thymus for forming the TCR repertoire is a basic rule for the formation of T cell repertoire. Recently, however, certain T cells have been reported to be generated extra-thymically and exhibit the restricted TCR repertoire. Some of these T cells are suggested to recognize self antigens in a non-MHC-restricted fashion. Those self antigens, such as endogenous retrovirus, surface activation antigens, and bacterial antigens, are induced by exogenous stress, transformation and invading microorganisms. T cells which recognize such self antigens seem to be activated and expand clonally whenever the antigens are expressed in the periphery. Although the biological roles of the unique T cells remain obscure, it is suggested that they may participate in immune surveillance system to monitor cell integrity and to destroy cells altered by transformation and infection by microorganisms.

Animals↗

PubMed1994

[Replacement of distal arch aneurysm: distal hemiarch replacement].

Among thoracic aortic aneurysm, operative result for distal arch aneurysm is poor. Approach auxiliary technique, and operative procedure are still controversial. We noticed that distal arch aneurysm frequently involve anterior lesser curvature of aortic arch, then we have designed "distal hemiarch replacement" that preserve branches of aortic arch and replace lesser curvature of arch sufficiently. Furthermore, we managed to prevent cerebral injury by atheromatous embolism using intraoperative echogram to detect atherosclerosis of aortic arch and the branches. Median approach, selective cerebral perfusion, and distal hemiarch replacement were performed consistently for seven distal arch aneurysm. As the result, all cases recovered without neurological deficit except one ruptured emergency case. Distal hemiarch replacement for distal arch aneurysm enabled sufficient essential removal and reconstruction of the thoracic aorta with minimal invasion. Intraoperative echogram could reduce operative cerebral injury and brought sufficient operative results.

Aged↗

PubMed1994

Isolated iliac artery aneurysm and its management.

The records of 16 patients with 44 aneurysms of the iliac artery during a 12-year period (1981 to 1992) were retrospectively reviewed. The mean age was 71.2 (range 53-81) years; the male/female ratio was 7:1. An extremely high incidence of isolated iliac artery aneurysm was noted relative to abdominal aortic aneurysm (11.7%) during the same period. Aneurysms ranged in size from 2 to 12 cm. Rupture occurred in four patients (25%). Six patients presented urologic complications of ureteral stenosis, with hydronephrosis caused by perianeurysmal fibrosis in five. Thirteen patients underwent surgical treatment with emergency operation performed in four with rupture and one with impending rupture. The mortality rate for ruptured aneurysm was high (50%). The operative procedures for common iliac aneurysms were open resection in 18, aneurysmectomy in two, and thromboexclusion in three. For internal iliac aneurysms, the procedures were aneurysmorrhaphy (partial resection) in five, obliterative endoaneurysmorrhaphy in seven, aneurysmectomy in two, and thromboexclusion in two, with appropriate graft replacement. Endarterectomy and reimplantation of the inferior mesenteric artery, and internal iliac artery graft interposition were performed to prevent colon ischaemia in three and two patients, respectively. Ureterolysis was performed in three patients with ureteral stenosis caused by perianeurysmal fibrosis, which improved hydronephrosis and renal function in two. Early diagnosis and elective surgery before rupture is the treatment of choice for saving the patient's life. The importance of preventing colon ischaemia for bilateral internal iliac aneurysms and ureterolysis for ureter entrapped within perianeurysmal fibrosis is emphasized.

Aged↗

PubMed1994

[A surgical treatment of ruptured arch aneurysm].

A 83-year-old woman was admitted to our hospital because of back pain and shock. Her chest X-ray and CT scan demonstrated a large arch aneurysm and hemothorax, suggesting ruptured aortic arch aneurysm. The ruptured aortic arch aneurysm was replaced with a woven Dacron graft under selective cerebral perfusion (SCP). Her postoperative course was uneventful without any neurological deficits. For the past three years, we have utilized SCP in 12 cases of arch aneurysms. There were three early deaths in this series. The cause of death were bleeding in one patient and cerebral accident in two patients. The latter two patients had severe atheromatous changes in the aortic wall. The SCP technique was a useful method of cerebral protection, especially for elderly patient with aortic arch aneurysm.

Aged↗

PubMed1994

[Ventricular septal perforation following acute myocardial infarction in an 85-year-old woman].

An 85-year-old woman who experienced sudden severe chest and back pains was admitted to our hospital. On admission a pansystolic murmur was audible and the ECG showed an acute antero-septal myocardial infarction. Right heart catheterization revealed increased oxygen from the right atrium to the right ventricle, leading to the diagnosis of ventricular septal perforation (VSP). Hemodynamics of the patient were stabilized using only a low dosage of dopamine. However the heart weakened progressively, an operation was performed on the 13th day after the onset of the perforation. The post-operative course was uneventful. She is the oldest patient with VSP which has been successfully operated in Japan.

Aged↗

PubMed1993

A seal-less centrifugal pump (Baylor Gyro Pump) for application to long-term circulatory support.

We are developing a new centrifugal pump, the Baylor Gyro Centrifugal Pump (Gyro Pump), which can function for more than 2 weeks. The concept of the Gyro Pump is that a one-piece rotor-impeller with embedded permanent magnets, driven directly by a brushless direct current motor stator placed outside, rotates like a "gyroscope," and the rotor-impeller is supported by one pivot bearing at the bottom in accordance with the gyroscopic principle. This concept enables us to eliminate a driving shaft and a seal between the driving shaft and the blood chamber, which results in extending the life of the centrifugal pump. The blood passes through the space between the motor stator and the rotor to the impeller portion. In this preliminary phase, two pivot bearings were applied to support the rotor-impeller at the top and the bottom inside the blood chamber. Both pivot bearings showed less blood trauma and less thrombogenicity in in vitro and in vivo studies. The Gyro Pump is a promising second-generation centrifugal pump for long-term circulatory support in the near future.

Animals↗