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Biomedical subjects

K Ohishi

Publications and source records attributed to K Ohishi.

At least 127 records · Page 7Linked to original sources
PubMed1995

Long-term results after conservative aortic valve repair for aortic regurgitation with ventricular septal defect.

Aortic valve repair was performed in 61 patients having aortic regurgitation (AR) associated with ventricular septal defect (VSD). Preoperative regurgitation was classified according to the Sellers' classification and grade I was in 3 patients, grade II in 19, grade III in 34, and grade IV in 5 patients. Forty-six patients underwent only plication of aortic valve, and in 15 patients the commissuroplasty was added to reinforce the free edge of the cusp. Furthermore, aortoplasty (aortic annuloplasty) was performed in 11. Actuarial survival rate and freedom from reoperation rate were 91.6% and 87.2%, respectively at 10 years after the initial repair. The rate of freedom from deterioration for 22 patients showing grade I or II of AR before the initial operation was 86.4% at 1 year, 76.7% at 5 and 10 years, while the rate for 36 patients with grade III or more severe AR was 91.7% at 1 year, 77.4% at 5 years and 63.9% at 10 years. The rate at 10 years after operation between the two groups was different significantly (p < 0.05). Twenty among 22 patients having grade I or II of AR before operation were in NYHA class I, while 23 of 30 survivors with grade III or IV of AR were in class I, 6 in class II, and 1 in class III. Eight patients received reoperation and four of them underwent repeated conservative aortic valve repair, and one received aortic valve replacement at reoperation. Five of 7 survivors with reoperation improved in NYHA class I and 2 in class II. These results suggested that careful follow-up was required especially for the first 10 years after the initial operation in patients showing preoperative severe AR and receiving aortic repair.

Adolescent↗
PubMed1994

Thyroid hormone suppresses the differentiation of osteoprogenitor cells to osteoblasts, but enhances functional activities of mature osteoblasts in cultured rat calvaria cells.

The effects of thyroid hormone on osteoblastic differentiation and activity were studied in fetal rat calvaria (RC) cells cultured for up to 30 days in medium supplemented with thyroid hormone-depleted serum. In this condition, the cells proliferated and differentiated to form mineralized bone nodules (BN) and expressed osteoblastic markers such as alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). The continuous presence of triiodothyronine (T3) at 10(-9)-10(-8) M in the medium inhibited the osteoblastic differentiation: 34% decrease in ALP activity on day 12 and 60% decrease in BN formation on day 15 at 10(-8) M. T3 at these doses had no effect on the DNA content of RC cells at confluence (day 6). Short-term (48-h) exposure of T3 at 10(-9) M or higher decreased ALP activity when RC cells were differentiating (days 7-11). However, when BN formation by the cells had already reached a plateau (day 28), the activity was increased by treatment with T3 at 10(-7)-10(-6) M. OCN production was increased dose dependently by this treatment with T3 (2.1-fold and 1.3-fold of control at 10(-8) M on days 11 and 28, respectively). Similar increases were observed in the levels of OCN mRNA. In addition, increases in phosphorylated OPN in the medium (day 11) and mineralized matrix (day 28) were observed (1.5-fold at 10(-8)-10(-6) M), while OPN synthesis and the level of its mRNA were depressed by T3 (60-70% of control at 10(-8) M). These results suggest that T3 regulates osteoblastic differentiation and activity depending on the state of cell differentiation: T3 suppresses the differentiation of osteoprogenitor cells to osteoblasts, but enhances the functional activity of mature osteoblasts.

Alkaline Phosphatase↗
PubMed1994

Tricuspid valve replacement with the St. Jude Medical valve.

A study was conducted on 20 patients who underwent tricuspid valve replacement (TVR) with the St. Jude Medical (SJM) valve. Isolated TVR was performed on 9 patients, and additional mitral, or mitral and aortic valve replacements were performed on 11 patients. Four patients (20%) died in the early postoperative period, but there were no deaths related to the SJM valve in the tricuspid position. The mean follow-up period of the 16 survivors was 74.4 months, and there have been no deaths during the follow-up period. The postoperative actuarial survival rate was 80%, 10 years after surgery. Three patients, representing 0.25%/patient-months, developed valve thrombosis, the valve thrombosis-free rate being 72.8%, 10 years after surgery, while entrapment of a leaflet by endothelial pannus was found in one patient, representing 0.08%/patient-months. Thus, the incidence of all prosthetic valve-related complications was 0.34%/patient-months, and the postoperative complication-free rate was 65.3%, 10 years after surgery. The medium-term follow-up study of TVR with the SJM valve revealed no prosthetic valve-related deaths and a relatively low incidence of prosthetic valve-related complications. However, as with other mechanical valves, valve thrombosis was a major risk posed by the SJM valve in the tricuspid position.

Actuarial Analysis↗
PubMed1994

Limited effectiveness of FK506 administration for ongoing rejection in heterotopic rat heart transplantation.

A comparison was made of the histological findings for myocardial tissue of heterotopic transplanted rat hearts administered with FK506. ACI rats were used as donors and Lewis rats as recipients. FK506 was used for 6 days except for group I (control group). Group II received 0.32 mg/kg/day of FK506 from the day of operation while group III was given the same dosage from the 4th day after transplantation. Group IV was given 1.28 mg/kg/day of the agent from the day of grafting and group V received the same dose from the 4th postoperative day. The graft survival time was longer for all groups given FK506, but was significantly longer only for groups administered with FK506 from the day of operation. Histological studies performed 10 and 20 days after transplantation showed that a moderate rejection was seen in about half of the grafts receiving FK506 from the 4th day after grafting. An ultrastructural study of these cases showed that infiltrating large lymphocytes still remained in the interstitial tissues and that the cytoplasmic organelles of the myocytes had been focally destroyed. These results suggest that, although FK506 suppressed any further rejection, the effect might be limited and the myocardial changes of the cardiac graft might persist even after administration for ongoing rejection.

Animals↗
PubMed1994

1 alpha,25-dihydroxyvitamin D3 stimulation of osteopontin expression in rat clonal dental pulp cells.

Osteopontin (OPN) is a major phosphorylated non-collagenous protein isolated from bone. Rat clonal dental-pulp cell lines RPC-C2A and RDP4-1 produce and secrete OPN as a principal phosphoprotein. 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] is a potent calcitropic hormone which regulates calcified tissue metabolism including the synthesis of extracellular matrix proteins. The effects of 1,25(OH)2D3 on the expression of OPN mRNA and the synthesis of OPN protein by pulp cells in vitro were investigated. In RPC-C2A cells, 1,25(OH)2D3 markedly stimulated synthesis of both [32PO4]- and [35S]-methionine-labelled OPN. Phosphorylated OPN synthesis increased dose-dependently and showed a maximum level at 48 h after addition of 10(-11)-10(-7) M 1,25(OH)2D3. Similar stimulation was also observed in RDP4-1 cells. Northern hybridization analysis revealed that 1,25(OH)2D3 greatly increased the level of OPN mRNA in both pulp cell lines. Examination of the time course of the effects of 1,25(OH)2D3 on the level of OPN mRNA in RPC-C2A cells by dot-blot analysis showed that stimulation was detectable at 24 h and reached a maximum at 48 h after exposure to 10(-7)M 1,25(OH)2D3. These findings indicate that 1,25(OH)2D3 stimulates the production of dental-pulp OPN by a mechanism that involves de novo synthesis and transcriptional control.

Animals↗
PubMed1994

Characterization of adherent T cells to human endothelial cells in patients with HTLV-I-associated myelopathy.

To clarify the phenomenon of increased adherence of T cells to endothelial cells (EC) in patients with HTLV-I-associated myelopathy (HAM), we determined the surface markers and expression of lymphocyte function antigen-1 (LFA-1) in T cells adherent or nonadherent to EC. The percentage of activated or HLA-DR+ T cells and the expression of LFA-1 in the adherent cell population were significantly higher than those in the nonadherent cell population. Moreover, the CD4 to CD8 ratio of the HLA-DR+ cells in the EC-adherent T cells was significantly higher than that in the nonadherent cells. Collectively, these results indicate that increased adherence of T cells to EC in HAM patients is based on the increase of activated T cells with high density LFA-1 expression in the peripheral blood. Moreover, CD4+ HLA-DR+ cells exhibited more adhesive activity to EC than CD8+ HLA-DR+ cells, suggesting that activated CD4+ cells, rather than activated CD8+ cells, may be important as the first trigger for T cell-infiltration to the central nervous system in the immunopathogenesis of HAM.

Adult↗
PubMed1994

Antiproliferative factor against the human glioblastoma cell line T98G identified in culture supernatants of CD4+ cells from patients with HTLV-I-associated myelopathy.

We investigated culture supernatants of peripheral blood mononuclear cells (MNC) derived from patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) for antiproliferative activity against the human glioblastoma cell line T98G. When T98G cells were cultured with condition medium containing culture supernatants of MNC from patients with HAM, the proliferation of T98G cells was significantly suppressed, compared with that of supernatants from HTLV-I seropositive carriers or seronegative controls. To clarify which population of MNC produced the antiproliferative humoral factor for T98G cells, we separated MNC into macrophage-depleted or B cell depleted populations, and further to both CD4+ and CD8+ T cells by using the panning method or plastic adherence. These studies demonstrated that the antiproliferative activity was mediated by a humoral factor produced by T cells, specifically CD4+ cells. This activity was blocked by a neutralizing monoclonal antibody against interferon-gamma (IFN-gamma). Moreover, IFN-gamma levels were elevated in the culture supernatants of CD4+ cells from HAM patients. Thus, the antiproliferative activity against T98G cells is mainly due to IFN-gamma derived from CD4+ cells of patients with HAM.

Adult↗
PubMed1994

Production of granulocyte-macrophage colony stimulating factor by human T-lymphotropic virus type I-infected human glioma cells.

We investigated the production of granulocyte-macrophage colony stimulating factor (GM-CSF) by human T-lymphotropic virus type I (HTLV-I)-infected human glioma cells (KG-1-C and T98G). When glioma cells were co-cultured with HTLV-I-producing T cell lines (HCT-1 and MT-2), GM-CSF was detected in the culture supernatant. GM-CSF was produced in all the co-cultures even after several passages. In co-cultures of KG-1-C and HCT-1 cells with Millicell, the amount of GM-CSF produced in the supernatant was almost as low as in the culture of HCT-1 alone. Moreover, for co-cultures of KG-1-C and HCT-1 or MT-2 cells, the production of GM-CSF was significantly suppressed in the presence of IgG from patients with HAM. Double-label immunostaining showed that GM-CSF-producing glioma cells always were stained by a monoclonal antibody against HTLV-I p19, indicating that HTLV-I infection of glioma cells caused GM-CSF production. These data suggest that human glial cells infected with HTLV-I gain the ability to produce cytokines.

Antibodies, Monoclonal↗
PubMed1994

The St. Jude medical prosthesis in the mitral position.

To study the long-term results of the St. Jude medical prosthesis in the mitral position, 520 patients were evaluated who had undergone mitral valve replacement with St. Jude medical (SJM) prosthesis. Eighteen patients or 3.5% died in the early postoperative period (within 30 days after operation). The total follow-up was 2872 patient-years and late deaths occurred in 23 cases. Postoperative cerebral embolism occurred in six, bleeding complication in five, and thrombosed valve in two patients. Postoperative anti-coagulant therapy was initiated with both dipyridamole (300 mg/day) and warfarin potassium. After discharge from our hospital the patients underwent routine examination of their thrombo-tests or prothrombin times at least every 2-3 months, and the major thromboembolic or bleeding complication rate was 0.45%/100 patient-years. In a period of 12 years, severe hemolysis following implantation was seen in seven patients. The cause of this hemolysis was perivalvular leakage in two patients but there were no leakages in the other five patients, although preoperative moderate to severe liver dysfunction was noted. Ninety-three percent of the patients were followed up, and their postoperative New York Heart Association functional classes were I or II in 88.6% of the cases. Their clinical results after mitral valve replacement with SJM prosthesis in the anti-anatomical position showed excellent durability and a low incidence of valve-related complications.

Adolescent↗
PubMed1994

Juxtamedullary microvascular dysfunction during the hyperfiltration stage of diabetes mellitus.

This study was designed to identify and localize defects in renal microvascular function during the hyperfiltration stage of diabetes mellitus. Male Sprague-Dawley rats were injected intravenously with 65 mg/kg streptozotocin (IDDM rats) or vehicle (sham rats). IDDM rats received insulin (3 U.kg-1.day-1) via an osmotic minipump; sham rats received diluent. During the ensuing 2-wk period, blood glucose levels averaged 89 +/- 2 mg/dl in 33 sham rats and 290 +/- 13 mg/dl in 37 IDDM rats. At the end of this period, inulin clearance was elevated in eight IDDM rats (1.43 +/- 0.17 ml.min-1.g kidney wt-1) compared with six sham rats (0.78 +/- 0.05 ml.min-1.g kidney wt-1). The remaining animals served as tissue donors for study of the renal microvasculature using the in vitro blood-perfused juxtamedullary nephron technique. Kidneys from sham and IDDM rats were perfused with homologous blood at a renal arterial pressure of 110 mmHg. Juxtamedullary single-nephron glomerular filtration rate was higher in IDDM rats (41.5 +/- 5.4 nl/min) than in sham rats (25.4 +/- 2.4 nl/min). Afferent arteriolar inside diameter was greater in IDDM rats (34 +/- 2 microns) than in sham rats (22 +/- 1 microns); however, efferent arteriolar diameter did not differ between groups. The afferent arteriolar vasoconstrictor response to norepinephrine (NE) was attenuated in IDDM rats, relative to sham rats, over a wide range of NE concentrations. In contrast, NE evoked similar degrees of efferent vasoconstriction in IDDM and sham rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Modification of delipidated apoprotein B of low density lipoprotein by lipid oxidation products in relation to macrophage scavenger receptor binding.

It is known that macrophages recognize and take up oxidized low density lipoprotein (LDL) and this macrophage recognition has been suggested to be due to modification of the lysine (Lys) residues of apoprotein B (apo B). In order to determine whether such modification is involved in recognition, delipidated apo B was modified with lipid peroxidation products and the macrophage recognition of the modified apo B was examined. When delipidated apo B was treated with linoleic acid 13-mono-hydroperoxide (LOOH) and trans-2-octenal (octenal), apo B became fluorescent and its Lys and histidine (His) residues were decreased. When delipidated apo B, partially methylated at the epsilon-amino groups of Lys residues, was treated with LOOH and octenal, fluorescence was not produced and the free Lys residues were not decreased. LOOH- and octenal-modified delipidated apo B were recognized by mouse peritoneal macrophages. The macrophage recognition of the modified apo B was prevented by maleyl bovine serum albumin, indicating that the scavenger receptor was involved in recognition. Neither methyl apo B nor methyl apo B, modified with LOOH or octenal, was recognized by macrophages. Neutralization of positively charged Lys residues of apo B by modification with LOOH and octenal may be requisite for recognition. Bovine serum albumin modified with LOOH and octenal prevented the recognition of the modified apo B, indicating that none of the intrinsic structure of apo B is required for recognition.

Aldehydes↗
PubMed1994

Coronary artery bypass grafting in elderly patients.

To determine the benefits of coronary artery bypass grafting (CABG) in elderly patients, we evaluated 37 patients more than 70 years old who underwent this surgical procedure and compared the results with those in 177 younger patients. Three-vessel lesions and left main lesion were seen in 78.4% and 48.6% of the elderly patients, respectively. Emergency or urgent surgery was performed on 19 patients and the number of distal anastomoses was 3.0 +/- 0.8 per patient. Left main lesion and emergency surgery were more common in elderly patients than in younger patients. Twelve patients received CABG with only a saphenous vein graft (SVG), while the remaining 25 patients had at least one arterial graft. The quality of the saphenous vein was poor to moderate in 50% of the elderly patients, while none of the arterial grafts showed significant sclerotic change. In 17 elderly patients, the ascending aorta showed sclerotic lesions and care was taken when completing proximal anastomoses of SVG to the aortic wall. After surgery, mechanical ventilation was required for an average of 29 h, which was longer than that in the younger patients. Postoperative low cardiac output, hypertension, and arrhythmia occurred in 6, 6 and 15 elderly patients, respectively. There were no early deaths, although there was one hospital death due to posttransfusion hepatitis. Thirty four elderly patients were classified as New York Heart Association functional class I or II during late follow-up maximum of 5 years) and only one had postoperative angina. The ascending aorta showed more sclerotic lesions, and the quality of the saphenous vein was worse, in the elderly patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Cardiac lipoma with changes of ST segment and T wave on electrocardiogram.

We report a case of cardiac lipoma found by chance as a cause of ST-T changes which suggested left ventricular hypertrophy. A 38-year-old man was completely asymptomatic and was incidentally found to have an abnormal electrocardiogram during a regular physical examination. Echocardiography revealed an oval mass located in the inferior wall of the left ventricle near the apex, and there was no finding of left ventricular hypertrophy. Computed tomography and magnetic resonance imaging, rather than echocardiography, were useful in determining the characteristics of the lipoma in this case. The tumor was resected by operation and the histology showed lipoma with no evidence of malignancy.

Adult↗
PubMed1994

A study of reservoir implantation--especially with saphenous vein graft catheterization.

Intra-arterial infusion chemotherapy is commonly used to treat hepatocellular carcinomas (HCC) and metastatic liver cancer after hepatectomy or in unresectable patients, and it has been adopted at Kurume University Hospital as a treatment for HCC. As complications of reservoir implantation have been encountered, the implantation procedure needs improvement. Procedures were compared in a study with 109 patients who were available for follow-up observation among 116 patients who underwent reservoir implantation. Fifty-six of the patients received intraoperative implantation through the gastroduodenal artery (GDA catheterization), 31 received external catheterization (EXT catheterization) and 22 received catheterization using a saphenous vein graft (SVG catheterization). The complication rates were 75.0%, 9.7% and 13.9% and the one-year patencies were 44.1%, 70.6% and 79.4%, respectively. GDA catheterization was no better than the other two procedures and it had a higher incidence of complications and a lower patency. SVG catheterization achieved good patency, although it had a little higher incidence of complications than external catheterization. It was presumed to be a procedure that would ensure reservoir implantation even in patients with a winding or variation of hepatic artery.

Catheters, Indwelling↗
PubMed1994

Role of cell-mediated immunity in bovine leukemia virus (BLV) infection in ruminants: its implication for the vaccination strategy against retroviruses.

Recent studies in the immunopathogenesis of bovine leukemia virus (BLV) infection in ruminants, reviewed herein, provide an insight into the vaccination strategy against retrovirus infection. It was shown that vaccination of naive sheep with a recombinant vaccinia virus (RVV) expressing BLV envelope glycoprotein protected the animals against BLV infection. The involvement of cell-mediated immunity (CMI) in this phenomenon was strongly suggested. The postinfection vaccination, that is, the vaccination of BLV-infected animals with RVV, also significantly suppressed BLV replication in the carrier animals. These findings support the idea that vaccination against retroviruses should put its emphasis on the induction of CMI and that such vaccine could be used not only for prophylactic but also for therapeutic purposes.

Animals↗
PubMed1994

[A case of incidental renal leiomyosarcoma].

A 68-year-old man visited his home doctor with the chief complaint of left flank pain. Abdominal ultrasonography revealed left hydronephrosis and space occupying lesion in the right kidney. He was referred to our hospital because of suspected left ureteral stone and for further examination. Drip infusion pyelography revealed a left ureteral stone and retrograde pyelography showed extrinsic compression and deformation of the right pyelogram. A computed tomography showed a heterogeneous solid mass, 7 x 4 cm in size, compressing the pelvicocalyceal system and growing out of the kidney. Right radical nephrectomy was performed under the diagnosis of renal cell carcinoma. The pathological diagnosis was leiomyosarcoma. Seventy-five cases of renal leiomyosarcoma have been reported in the Japanese literature and this is the third case as an incidental tumor. Because of the absence of the characteristic diagnostic signs, this malignant tumor can present diagnostic difficulty. The diagnostic problems and clinical features of renal leiomyosarcoma are discussed.

Aged↗