Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 487 records · Page 27Linked to original sources

PubMed1996

[An approach to the emergency surgery for arch and/or ascending aortic aneurysm].

The outcome of emergency surgery for the aortic arch aneurysm and/or dissecting aneurysm is worse than that of elective surgery. To decide the future strategy of the emergency surgery for these disease, 11 patients with emergency surgery (= group E: 8 for aortic dissection and 3 for rupture of the aortic arch aneurysm, age; 61 +/- 13 SD) were compared with 12 patients who had elective surgery (= group S: 5 for aortic dissection and 7 for aortic arch aneurysm, age; 69 +/- 3 SD). Ascending aorta replacement was performed in 7 cases in group E v.s. 1 in group S, aortic arch replacement in 2 v.s. 5, ascending aorta and aortic arch replacement in 1 v.s. 4 and patch replacement of the aortic wall in 1 v.s. 2, respectively. Selective cerebral perfusion (SCP) upon the cardiopulmonary bypass (CPB) was used in 45% (5/11) in group E. v.s. in 92% (11/12) in group S, p < 0.05. CPB time, aortic clamp time and SCP time were not significantly different between E group and S group. Postoperative cardiac failure, respiratory failure, renal failure, brain injury and infection occurred at insignificant rates between both groups. Thirty-day and 3-year survivorships were 73% in group E, while in group S they were 92% and 75%, respectively. In group E there were 2 cases which had aortic wall injury due to the aortic clamp used during the surgery. We recommend the use of selective cerebral perfusion and open distal anastomosis in emergency surgery for aortic arch aneurysm and/or Stanford type A aortic dissection.

Aged↗

PubMed1996

MR of the submandibular gland: normal and pathologic states.

PURPOSE: To evaluate the MR appearance of normal and pathologic states of the submandibular gland. METHODS: MR images of 22 healthy subjects and 21 patients with histopathologically confirmed disorders of the submandibular gland (five pleomorphic adenomas, two hemangiomas, two malignant lymphomas, one adenoid cystic carcinoma, one squamous cell carcinoma, and 10 cases of sialadenitis) were reviewed. RESULTS: All normal submandibular glands showed higher signal intensity than surrounding muscle but lower intensity than fat on T1-weighted and T2-weighted images. Postcontrast images showed moderate enhancement of the gland. All the tumors had lower signal intensity than the normal submandibular gland on T1-weighted images and had intermediate to high (n = 8) or high (n = 3) signal intensity relative to the normal submandibular gland on T2-weighted images. Six of seven benign tumors were well defined, and three of four malignant tumors were poorly defined. In all cases of sialadenitis, the submandibular gland showed diffusely different signal intensities from the normal gland on both T1-weighted and T2-weighted images. Eight cases of chronic sialadenitis showed lower T2-weighted signal intensities than the normal gland, and this can be explained histopathologically by marked fibrosis and cellular infiltration. CONCLUSIONS: MR imaging can show the presence, extent, margins, and signal intensity changes of pathologic conditions of the submandibular gland.

Adenoma, Pleomorphic↗

PubMed1996

[Thoracoscopic closure of patent ductus arteriosus for children: two case report].

We reported thoracoscopic closure of patent ductus arteriosus (TCPDA) performed on two children. All of two patients had no residual shunt postoperatively. Postoperative pain was less than left thoracotomy procedure. In addition TCPDA had merits cosmetically. We concluded that TCPDA was less invasive and safety procedure compared with conventional procedure.

Child, Preschool↗

PubMed1996

[A case of pulmonary sarcoma with a differential diagnosis from preoperative pulmonary thromboembolism].

Primary sarcoma of pulmonary artery is a rare tumor. A 46-year-old man was hospitalized because of dyspnea and hemoptysis. Pulmonary thromboembolism was suspected by chest X-ray, scintigraphy, and CT. But the mass had a to-and-fro movement above the pulmonary valve on pulmonary arterial cineangiography. We strongly suspected that it was primary neoplasm of pulmonary artery. The pulmonary artery was opened under cardiopulmonary bypass. The tumor arised pulmonary trunk and extended peripherally. The tumor was surgically removed as complete as possible, though a proxymal balloon embolectomy was unsuccessful. The histological finding was malignant fibrous histiocytoma of the pulmonary artery.

Cardiopulmonary Bypass↗

PubMed1996

Gene therapy against an experimental glioma using adeno-associated virus vectors.

The efficacy of gene therapy for glioma was examined using adeno-associated virus (AAV)-based vectors to deliver genes to experimental tumors in mice. Stereotactic injection of 2 x 10(5) U-251SP human glioma cells into the brains of nude mice produced tumors of 19.06 +/- 1.79 mm2 17 days after injection. Employing a high titer preparation of AAV vector containing the gene for beta-galactosidase (AAV-lacZ), dose-dependent transduction of U-251SP cells was seen in vitro. When 1.6 x 10(10) AAV-lacZ particles were directly injected into tumors in vivo, 30-40% of the cells along the needle track expressed beta-galactosidase. Transduction of U-251SP cells in vitro with an AAV vector containing a bicistronic gene encoding both herpes simplex thymidine kinase and human interleukin-2 (AAV-tk-IRES-IL2) rendered them sensitive to the cytocidal effects of ganciclovir (GCV) and IL-2 was produced in a dose-dependent manner. Cocultures of AAV-tk-IRES-IL2 transduced cells and nontransduced cells proved highly sensitive to GCV indicating the contribution of the bystander effect. Stereotactic delivery of 6 x 10(10) AAV-tk-IRES-IL2 particles into day 7 tumors in nude mice followed by administration of GCV for 6 days, resulted in a 35-fold reduction in the mean volume of tumors compared with controls. Normal brains did not suffer from any toxic effect of the administration of AAV-tk-IRES-IL2 and GCV. These results indicate that high titer AAV vector treatment may be safe and effective for in vivo gene therapy of human brain tumors.

Animals↗

PubMed1996

[Radical prostatectomy for localized prostate cancer].

We studied 81 patients who underwent radical prostatectomy for prostate cancer. Ten, 57 and 14 patients were clinically diagnosed with stage T1, T2 and T3, respectively. Pelvic lymph node dissection was performed prior to prostatectomy in all cases. The neurovascular bundle was preserved in 21 patients. Compared with pathological stage, the accuracy rate of clinical staging in T1, T2 and T3 was 40, 46 and 64% respectively. Approximately half of the patients clinically diagnosed with stage T2 were pT3. The positive rate of lymph node in pT2 and pT3 was 3.3 and 37% respectively, showing a marked difference between these two pathological stages. The 3-year non-recurrence rates were 89% in patients with pT2 and 79% in pT3. In the well differentiated carcinoma group, no patients had recurrence for up to 3 years. All of the patients with infiltration (INF) gamma showed recurrence within 3 years. Fifty-five patients had no problem on urination post-operatively, while the other 23 patients had a mild or moderate incontinence and the remaining 3 patients had a small urine stream. Regarding erectile potency, 4 out of 18 evaluable patients were potent.

Aged↗

PubMed1996

Changes of expression of complement 3bi receptors on granulocytes after physical exercise in rats.

OBJECTIVE: The purpose of this study was to examine the effects of physical exercise on the expression of clusters of differentiation (CD)11b, CD18 and CD 54 on granulocytes and complement 3bi (C3bi)-dependent functions in rats. EXPERIMENTAL DESIGN: The rats were separated into two groups: the control group (n = 21) and the training group (n = 14). The rats in the training group were subjected to a program that consisted of swimming 6 days in a week for 7 weeks. MEASURES: The phagocytic and hydrogen peroxide (H2O2) generating activities and the expression of receptors on granulocytes were measured using flow cytometric techniques. RESULTS: The acute swimming and the 7 weeks of swim training caused high C3bi-dependent phagocytic activity of granulocytes. Swim training led to an increase of H2O2 generating activity together with C3bi-dependent phagocytosis both immediately after and 24 hrs after the 120 min swimming. The 24 hrs recovery from the 120 min swimming in trained and untrained rats caused an increase of H2O2 generating activity of granulocytes. In the training group, an increase in this activity could be observed immediately after the 120 min swimming exercise. The upregulation of the CI1b on granulocytes was induced by the 120 min of swimming regardless of swim training. CONCLUSIONS: These results suggest that the increase of C3bi receptor-dependent phagocytosis and H2O2 generating activities induced by the physical exercise might depend on the upregulation of the CD11b that is the component of C3bi receptor.

Animals↗

PubMed1995

Multiple isoforms of guinea pig decay-accelerating factor (DAF) generated by alternative splicing.

Human decay-accelerating factor (DAF, CD55), which is one of the regulators of complement activation (RCA), prevents complement activation on homologous cell membranes, resulting in a functional discrimination between self cells and invading microorganisms. DAF is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein and has been identified at the molecular level only in primates. We have isolated guinea pig DAF cDNA clones from a spleen library and identified six different classes. All encode the same four short consensus repeat domains with 58% amino acid sequence identity to human DAF, but show variability in the C-terminal region. Alternative splicing of two optional exons generates transmembrane, GPI-anchored, and secreted forms of guinea pig DAF, and differential usage of splice sites in the single exon composed of internally quintuplicated sequences generates variable Ser/Thr-rich regions. Multiple isoforms were expressed ubiquitously in all tissues and cells tested. Similar variability in the Ser/Thr-rich region has been reported in human membrane cofactor protein (MCP), another membrane inhibitor of the RCA family. There seems to be a common ancestral sequence in DAF and MCP consisting of a Ser/Thr-rich region, but obviously multiplication occurred independently, indicating the importance of variability of the Ser/Thr-rich region for the effective regulation of complement activation.

Alternative Splicing↗

PubMed1995

The substantia nigra is a major target for neurovirulent influenza A virus.

Clinical and immunohistochemical studies were done for 3-39 d on mice after intracerebral inoculation with the neurovirulent A/WSN/33 (H1N1; WSN) strain of influenza A virus, the nonneurovirulent A/Aichi/2/68 (H3N2; Aichi) strain, and two reassortant viruses between them. The virus strains with the WSN gene segment coding for neuraminidase induced meningoencephalitis in mice. The mice inoculated with the R96 strain, which has only the neuraminidase gene from the WSN strain, had mild symptoms and weak positive immunostaining to the anti-WSN antibody in meningeal regions. Both the WSN and R404BP strains, which contain the WSN gene segments coding for neuraminidase and matrix protein, were clearly neurovirulent both clinically and pathologically. On day 3 after inoculation with either of these two strains, WSN antigen was detected in meningeal and ependymal areas, neurons of circumventricular regions, the cerebral and cerebellar cortices, the substantia nigra zona compacta, and the ventral tegmental area. On day 7, meningeal reactions and neuronal staining were still seen, and advanced accumulation of the viral antigen was evident in the substantia nigra zona compacta and hippocampus. Double immunostaining demonstrated that the WSN antigen was only seen in neurons and not in microglia or reactive astrocytes. Immunostaining for the lectin maackia amurensis agglutinin, which recognizes the Neu5Ac alpha 2,3 Gal sequence, which serves as a binding site for influenza A virus on target cell membranes, showed that positive staining was localized in the ventral substantia nigra and hippocampus. These results suggest that neurovirulent influenza A viruses could be one of the causative agents for postencephalitic parkinsonism.

Animals↗

PubMed1995

A monoclonal antibody that blocks the complement regulatory activity of guinea pig erythrocytes and characterization of the antigen involved as guinea pig decay-accelerating factor.

MCA44 is a mAb with the capacity to sensitize neuraminidase-treated guinea pig E for hemolysis by homologous guinea pig C, and the Fab fragments of this mAb could also sensitize guinea pig E interfering with the function of a membrane inhibitor of C on guinea pig E. Using an immunosorbent column to which MCA44 was coupled, the antigenic molecule termed 44Ag was purified from the glycoprotein fraction extracted from E membranes. C intermediate sheep E treated with guinea pig C1 and C4 after sensitization with Ab (EAC14b cells) lost the ability to generate C3 convertase with C2 after incubation with 44Ag. Treatment of guinea pig E and PBL with phosphatidyl-inositol specific phospholipase C (PIPLC) partially removed 44Ag, as determined by flow cytometric analysis after immunofluorescence staining with MCA44. However, 125I-labeled 44Ag adsorbed to human E was efficiently removed by PIPLC treatment with a slight reduction in M(r). The 44Ag purified on an immunosorbent column showed three bands on SDS-PAGE. However, partial N-terminal amino acid sequences of the 55-kDa, 70-kDa, and 88-kDa bands under nonreducing conditions were identical and the sequence was 55% homologous to the N-terminal sequence of human decay accelerating factor (CD55). Intracutaneous administration of MCA44 or its F(ab')2 fragment resulted in increased capillary permeability, even after 3 days, as determined by the appearance of Evans blue spots after i.v. administration of the dye. Because control Abs including anti-class I-MHC did not cause such increased capillary permeability, the increase in permeability caused by MCA44 was likely induced by blocking the function of 44Ag in vivo, indicating a crucial role for these molecules in preventing over-activation of C at the site.

Amino Acid Sequence↗

PubMed1995

Novel antitumor indolocarbazole compound 6-N-formylamino-12,13-dihydro-1,11- dihydroxy-13-(beta-D-glucopyranosyl)-5H-indolo[2,3-a]pyrrolo[3,4- c]carbazole-5,7(6H)-dione (NB-506): induction of topoisomerase I-mediated DNA cleavage and mechanisms of cell line-selective cytotoxicity.

A new indolocarbazole antitumor agent, NB-506 [6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl) -5H- indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione], enhanced the DNA cleavage catalyzed by HeLa S3 topoisomerase I at 0.01 microM but not the cleavage by topoisomerase II at 300 microM. It also caused single-strand DNA breakage in intact cells at 0.08 microM and more. Unlike the known topoisomerase I inhibitor camptothecin, NB-506 intercalated with DNA. However, the binding affinity to DNA and the inhibition against DNA polymerase alpha and RNA polymerase II were marginal compared with those of Adriamycin or actinomycin D. NB-506 inhibited the growth of various tumor cell lines at two micromoles or less, and its cytotoxicity was found to be cell line selective. This selective cytotoxicity of NB-506 was not fully explained by the differences in topoisomerase I activity in these cell lines, but there was some relationship between the amount of NB-506 accumulated in these cell lines and its cytotoxicity toward them. In conclusion, NB-506 is a potent topoisomerase I poison, acting selectively on tumor cell lines accumulating NB-506.

Animals↗

PubMed1995

Cloning of a swelling-induced chloride current related protein from rabbit heart.

Recently, pIcln has been reported to be a regulator of a swelling-induced chloride conductance. We have cloned a cDNA RCL-H1 from rabbit heart, of which primary structure is highly homologous to that of pIcln. Outwardly rectifying currents were recorded in oocytes expressing RCL-H1, which is consistent with the result of pIcln. RNA blot analysis revealed the widespread expression of RCL-H1 mRNA in rabbit tissues. RCL-H1 may play an important role in regulating cell volume and give a clue to revealing molecular structure of swelling-induced chloride channel(s).

Amino Acid Sequence↗

PubMed1995

Use of the Bo-RBC-SCID mouse model for isolation of a Babesia parasite from grazing calves in Japan.

SCID mice with circulating bovine red blood cells (Bo-RBC-SCID mice) were used to isolate Babesia parasites from grazing calves in Japan. Although the initial blood samples obtained from the calves contained both Babesia and Theileria parasites, we were able to isolate only the Babesia parasites by repeated blood passages in Bo-RBC-SCID mice, taking advantage of the much more rapid growth of Babesia than of Theileria. The parasites isolated had characteristics of large-type Babesia, showing typical paired pyriform morphology. The Bo-RBC-SCID mice infected with the Babesia parasites developed a high level of parasitemia, showing severe clinical symptoms characterized by hemoglobinuria, jaundice, and hemolytic anemia. In addition, some mice exhibited nervous symptoms, particularly paralysis of both posterior limbs. The results demonstrated that the Bo-RBC-SCID mouse model was useful not only for isolating Babesia from cattle but also for studying the disease caused by the Babesia infection.

Agriculture↗

PubMed1995

Human Aortic Vascular Smooth Muscle Cells Digest Extracellular Matrix by Elaboration of Plasminogen Activators: Implications for Atherogenesis.

Migration and proliferation of vascular smooth muscle cells (SMCs) are hallmarks of atherogenesis and restenosis after angioplasty. Digestion of surrounding extracellular matrix (ECM) may be a critical link. To determine whether invasion of ECM by human aortic SMCs (HASMCs) depends on proteolytic digestion mediated by the cells themselves, we characterized ECM digestion in terms of solubilization of 3H-proline--labeled ECM, produced by the use of rat aortic SMCs, by HASMCs under various conditions. Plasmin alone (10 µg/ml) digested 80% of ECM in 2 hours. HASMCs in 10% fetal bovine serum cultured on ECM that was not exposed to plasmin digested 48% of the ECM in 7 days. When HASMCs were cultured on plasmin-pretreated ECM, only 14% of the residual ECM was digested. Conditioned media or cells cultured on porous membrane 1 mm removed from the ECM had no effect. Baseline secretion of tissue-type plasminogen activator (t-PA) into the media by HASMCs averaged 3.9 ng/105 cells/24 hr and baseline secretion of type-1 plasminogen activator inhibitor (PAI-1) averaged 1300 ng/105 cells/24 hr. Thrombin (5 U/ml) increased t-PA antigen production by 184% without altering PAI-1 activity and increased ECM degradation by 43% in 7 days. Transforming growth factor-beta (TGF-beta) decreased t-PA antigen production, increased PAI-1 activity, and decreased ECM degradation. These results suggest that (1) HASMCs can digest naturally produced ECM; (2) plasminogen-dependent mechanisms requiring cell contact are important in the initiation of this phenomenon; and (3) thrombin in the vicinity of clots may modulate the fibrinolytic and proteolytic properties of SMC through t-PA after vascular injury.

Journal Article↗

PubMed1995

Methylprednisolone inhibits increase of interleukin 8 and 6 during open heart surgery.

It has been reported that interleukin 8 (IL-8) and interleukin 6 (IL-6) are two of the chemical mediators causing myocardial injury. It is not clear whether treatment with corticosteroids in vitro in these patients can prevent the production of interleukin 8 and 6. This prospective study was conducted to investigate whether methylprednisolone (MP) pretreatment (30 mg.kg-1 before CPB and before declamping of aorta) influenced the production of IL-8 and 6 in the peripheral circulation in 27 patients undergoing elective coronary artery bypass surgery. The IL-8 and IL-6 concentrations were measured by ELISA kit. We also studied the effect of MP pretreatment on postoperative cardiac function. Serum concentration of IL-8 in non-MP-treated patients (37 +/- 44 pg.ml-1 preoperatively) increased to 169 +/- 86 pg.ml-1 60 min after declamping of the aorta (P < 0.001). The increase was greater than the increase from 22 +/- 8.9 pg.ml-1 to 52 +/- 35 pg.ml-1 in the MP-treated patients (P < 0.01). Serum IL-6 concentration in non-MP-treated patients increased from the preoperative value of 59 +/- 30 pg.ml-1 to 436 +/- 143 pg.ml-1 60 min after declamping of the aorta (P < 0.001). The increase was greater than the increase from 36 +/- 15 pg.ml-1 to 135 +/- 85 pg.ml-1 in the MP-treated patients (P < 0.01). Furthermore, postoperative cardiac index in MP-treated patients (3.6 +/- 1.1 L.min-1.m-2) was higher than 2.3 +/- 0.8 L.min-1.m-2 of non MP-treated patients (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗

PubMed1995

Detection of decay-accelerating factor in stool specimens of patients with colorectal cancer.

BACKGROUND & AIMS: Colorectal cancers have an increased expression of decay-accelerating factor (DAF). The aim of this study was to determine whether stool specimens of patients with colorectal cancer contain increased amounts of DAF. METHODS: DAF was measured using an immunoassay in the stool specimens of 40 persons with colorectal cancer, 18 with colorectal adenomatous polyps, 13 with upper gastrointestinal cancer, and 41 without gastrointestinal disease. RESULTS: Stool DAF concentrations in patients with colorectal cancer (0-9.8 ng/g stool; median, 1.6 ng/g) were significantly higher than those in patients with adenoma (0-6.4 ng/g; median, 0 ng/g) (P < 0.05), patients with upper gastrointestinal cancer (0-3.1 ng/g; median, 0 ng/g) (P < 0.05), and subjects without gastrointestinal disease (0-3.4 ng/g; median, 0 ng/g) (P < 0.01). Resection of colorectal cancers caused a marked decrease in stool DAF concentrations. The stool DAF test was positive in a substantial portion of patients with colorectal cancer whose tumors were small ( < 2 cm), at an early TNM stage, or unassociated with fecal occult blood positivity. The sensitivity of the test for colorectal cancer was 55%, and the specificity was 85%. CONCLUSIONS: The measurement of stood DAF deserves evaluation as a test for detection of colorectal cancer.

Adenomatous Polyposis Coli↗

PubMed1995

Oral calcium carbonate administration ameliorates the progression of renal failure in rats with hypertension.

Oral calcium supplementation is reported to have phosphate-binding and antihypertensive effects. Since both phosphate binders and antihypertensive agents are reported to attenuate renal injury, we studied the effect of oral calcium carbonate (CaCO3) administration on the course of renal deterioration using doxorubicin-induced renal failure in rats treated with deoxycorticosterone acetate and salt for 10 weeks. Rats were divided into four groups: the CaCO3 (6.0 g/kg/d) group (n = 12), the aluminum hydroxide (Al(OH)3; 6.0 g/kg/d) group (n = 11, as a phosphate-binder control), the hydralazine (10 mg/kg/d) group (n = 11, as an antihypertensive control), and the control group (n = 12). All agents were given as a mixed chow diet. Blood pressure and urinary protein excretion progressively increased in the control rats. CaCO3 and hydralazine lowered blood pressure, but Al(OH)3 did not (185 +/- 4 mm Hg, control; 160 +/- 5 mm Hg, CaCO3; 171 +/- 8 mm Hg, Al(OH)3; 156 +/- 5 mm Hg, hydralazine at week 10). Proteinuria was reduced in the rats treated with CaCO3 and Al(OH)3 compared with those without the treatment (986 +/- 86 mg/d, control; 551 +/- 54 mg/d, CaCO3; 527 +/- 31 mg/d, Al(OH)3; and 955 +/- 68 mg/d, hydralazine at week 10). Serum phosphate concentration and calcium phosphate products also were significantly lower in both the CaCO3 and Al(OH)3 groups than in the control group. At week 10, increased serum urea nitrogen, impaired renal function, and glomerular sclerosis present in the control group were significantly attenuated in both in the CaCO3 and Al(OH)3 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1995

Peripartum heart disease in cows.

Thirteen Holstein dairy cows aged 5.1-10.6 years died or were killed as a result of severe illness during the peripartum period, associated with lateral recumbency, moaning, tachycardia and dyspnoea. They were all high milk producers (> 9000 kg/year) and had experienced at least three pregnancies. The average duration of the clinical course was 2.5 +/- 1.7 days. Electro-cardiography revealed marked tachycardia associated with atrial fibrillation or atrioventricular dissociation. Serum clinical chemistry showed severe hypocalcaemia (3.6 +/- 1.3 mg/dl) and at necropsy multifocal myocardial necrosis was invariably found. Myocardial necrosis was accompanied by neutrophilic and mononuclear cellular infiltrates with interstitial fibrosis. The cause of this lesion was not established.

Animals↗