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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 505 records · Page 28Linked to original sources
PubMed1991

Biliary excretion of bile acid conjugates in a hyperbilirubinemic mutant Sprague-Dawley rat.

The hepatic transport of bile acid conjugates was studied in the Eisai hyperbilirubinuria rat, a Sprague-Dawley mutant rat with conjugated hyperbilirubinemia. Serum bile acid levels were increased, bile acid-independent bile flow was decreased and biliary glutathione concentrations were markedly decreased in the Eisai hyperbilirubinuria rat. Biliary excretion of sulfobromophthalein was markedly impaired and almost no glutathione conjugate was excreted in the bile of the Eisai hyperbilirubinuria rat. Biliary excretion of lithocholate-3-O-glucuronide and lithocholate-3-sulfate in the Eisai hyperbilirubinuria rat was markedly delayed, whereas that of lithocholate was only slightly delayed. After [14C]chenodeoxycholate infusion (1 mumol/min/100 gm for 60 min), the increases in bile flow and biliary excretion of isotope in the Eisai hyperbilirubinuria rat were not so prominent as those observed in control rats, and the glucuronide of chenodeoxycholate, which constituted about 15% of biliary chenodeoxycholate in control rats, was not observed in the Eisai hyperbilirubinuria rat. Initial uptake of lithocholate and its glucuronide and sulfate by isolated hepatocytes was not impaired in the Eisai hyperbilirubinuria rat; the profiles of cytosolic bile acid binding proteins in Eisai hyperbilirubinuria rat liver were identical to those in control liver. These data indicate that the Eisai hyperbilirubinuria rat has excretory impairment of organic anions, bile acid glucuronide and sulfate and that it has characteristics very similar to those of the hyperbilirubinemic mutant Wistar rats TR- and GY.

Animals↗
PubMed1991

Establishment and characterization of human medulloblastoma xenograft line.

A new xenotransplantable tumor line, MED-FU, was derived from a 6-year-old female patient with cerebellar medulloblastoma. This tumor was grown in nude mice as serially transplantable subcutaneous xenografts composed of small round cells with hyperchromatic nuclei and scant cytoplasm. Many rosettes and mitoses were observed. Immunohistochemically, glial fibrillary acidic protein (GFAP), S-100 protein, and neuron specific enolase (NSE) were not detected. The doubling time of the subcutaneous tumors was 6.8 days. Highly concentrated polyamines were detected in the tumor tissue and serum of tumor-bearing mice. This xenotransplanted tumor line, MED-FU, is considered to provide an available experimental model for the study of human medulloblastoma.

Animals↗
PubMed1991

Decrease in the specific forms of cytochrome P-450 in liver microsomes of a mutant strain of rat with hyperbilirubinuria.

Eisai-hyperbilirubinuria rats (EHBR) is a mutant originated from Sprague Dawley rats. The activities of UDP-glucuronyltransferase and drug metabolizing enzymes in EHBR were compared with those in Sprague Dawley rats as the control. The activity of aniline hydroxylase was significantly increased in liver microsomes of EHBR whereas the activity of ethylmorphine N-demethylase was found to be significantly decreased in EHBR as compared to control rats. In addition, the activity of testosterone 7 alpha-hydroxylase was increased in EHBR whereas the activity of testosterone 6 beta-hydroxylase was significantly decreased in EHBR as compared to control rats. Western blot analysis of liver microsomes of EHBR with antibodies to P-450IA2, P-450IIB1, P-450IIC11 and P-450IIIA2 showed that the amounts of P-450IIB1 and P-450IIIA2 in liver microsomes were significantly lower in EHBR than in control rats. These results indicated the form-specific alteration in the amounts of cytochrome P-450 in liver microsomes of EHBR.

Aniline Hydroxylase↗
PubMed1991

[Diagnosis of prosthetic mitral valve regurgitation by Doppler color flow imaging using right parasternal approach: a comparative study with transesophageal method].

Doppler color flow imaging is a useful tool in evaluating mitral regurgitation (MR). However, it is frequently difficult to assess prosthetic valve MR by the conventional transthoracic approach using left parasternal or apical echo-windows, because of the interception of ultrasound by the prosthesis or artifacts produced by its motion. The purpose of this study is to determine the usefulness of the "right" parasternal approach (RPA) in the echo diagnosis of prosthetic MR. Six patients with pathological prosthetic MR determined by transesophageal approach (TEA) were studied. Transthoracic echo was performed using both the RPA and the conventional approach, and the presence or absence and the extent of MR signals by these transthoracic approaches were compared with those by TEA. Prosthetic MR was detected in five of six patients by the RPA and the extent of MR signals by the RPA was very similar to that by TEE in each of the five patients. MR could not be detected by the RPA only in one patient, whose MR was estimated to be very mild by TEE. By the conventional approach, MR could not be detected in three patients and the degree of MR was significantly underestimated in two of the remaining three patients. Thus, the transthoracic RPA is often as useful as TEA in diagnosing prosthetic MR, which is often undetectable or underestimated by the conventional approach. Because the RPA is less invasive than TEA, the RPA should be encouraged in patients with suspected prosthetic mitral valve dysfunction.

Adult↗
PubMed1991

Activation of rainbow trout complement by C-reactive protein.

The activation of the complement system of rainbow trout by trout C-reactive protein (CRP) was investigated. Complement fixation tests were performed by using rabbit hemolysin-sensitized sheep erythrocytes and rainbow trout complement. Purified CRP increased the consumption of complement in the presence of Streptococcus pneumoniae C-polysaccharide (CPS), indicating the activation of the complement system. In contrast to this, acute phase serum activated the complement in the absence of CPS. Consumption of the complement by acute-phase serum was depressed when CRP was removed from acute-phase serum by CPS-sepharose 4B affinity chromatography. The acute-phase serum, as well as CRP plus CPS, suppressed in vitro growth of Vibrio anguillarum in the presence of complement, and enhanced the phagocytosis of the bacteria by glass-adherent peritoneal exudate cells. These results indicated that CRP has a role in host defense during acute-phase response through the activation of the complement system, enhancement of phagocytosis, and suppression of bacterial growth.

Acute-Phase Reaction↗
PubMed1991

[Effect, recurrence and prognosis of intra-arterial infusion chemotherapy with anticancer agents for advanced breast cancer--especially, the significance of tumor blood vessels].

Between January 1977 and March 1991, 86 patients of Stage III and Stage IV breast cancer were treated by intra-arterial infusion chemotherapy (IAIC) in Sapporo Medical College. The 5- and 10-year overall survival rates of Stage III b were: infusion group 53.1% and 53.1%, non infusion group 50.1% and 16.7%, respectively. A significant difference was seen in the 10-year survival rate (p less than 0.05). The 5- and 10-year overall survival rate of Stage III b histologically effective group was 67.3% and non-effective group 31.8%. A significant difference was seen between these two groups (p = 0.0241). A significant difference was seen between n2 positive Stage III b infusion group and non-infusion group in 7-year survival rate (p less than 0.01). The ischemic effect on tumor cells by degeneration changes of the blood vessels was important for the histological effect. Pre-operative angiography helped in the choice of anticancer agents. The sufficient adjuvant chemo-endocrine therapy will assure a good prognosis for IAIC-treated Stage III b breast cancer patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

[Selective enhancement of tumor blood flow and drug delivery to brain tumors in experimental rat gliomas under angiotensin II-induced hypertension].

Regional blood flow of brain tumors and normal brain tissue of rats before and during angiotensin II (AT II)-induced hypertension were measured using an electrolytic flowmeter and a laser flowmeter. Etoposide concentration in the tumor and brain tissue after intracarotid administration were also measured in brain tumor bearing rats with or without AT II-induced hypertension. A suspension of 5 x 10(5)/10 microliters 9L gliosarcoma cells was inoculated into the left caudate-putamen of CD Fischer 344 rats. Before induced hypertension, regional blood flow of the tumor (28.2 +/- 2.6 ml/100 g/min; mean +/- SEM) and the contralateral caudate-putamen (23.0 +/- 1.8 ml/100g/min) in the tumor bearing rats were significantly lower than that of the caudate-putamen (43.9 +/- 4.1 ml/100g/min) in the normal rats (p less than 0.01). Intravenous administration of AT II at a dose of 0.4-0.6 microgram/body/min increased the mean arterial blood pressure from 96.5 +/- 4.7 mmHg to 138.0 +/- 3.6 mmHg. AT II-induced hypertension resulted in an approximate 1.8(1.1 - 3.6)-fold increase in the regional tumor blood flow. On the other hand the regional blood flow of the contralateral caudate-putamen was slightly decreased at the rate of 6%. The mean concentration of etoposide with AT II-induced hypertension in the tumor tissue was 2.2-fold higher than that without AT II-induced hypertension. However, etoposide delivery to normal brain tissue was small. From these results, induced hypertension with intravenously administrated AT II selectively increase the tumor blood flow and drug delivery to brain tumor tissue. Intracarotid chemotherapy with AT II-induced hypertension might contribute to enhance therapeutic effect of malignant brain tumors.

Angiotensin II↗
PubMed1991

[Clinical course and prognosis in SLE patients with pulmonary hypertension: a comparative study with primary pulmonary hypertension].

Recently pulmonary hypertension (PH) has been recognized as one of life threatening complications which determine the prognosis of patients with systemic lupus erythematosus (SLE). Clinical aspects and pathology in patients with SLE complicated by PH (SLE-PH) have been reported to have a close similarity to those in patients with primary pulmonary hypertension (PPH), the prognosis of which is very poor in general. However, the long-term prognosis for patients with SLE-PH is not clear yet. Mainly because of some technical limitations for determining the severity of the PH, long-term follow-up studies have been inconclusive. In this study, 7 patients with SLE-PH and 6 patients with PPH were studied by using two-dimensional echocardiography. The interventricular septal curvature (R) was measured from the parasternal short axis view and the reciprocal value (1/R) was applied as a severity index of the PH. In 4 patients with SLE-PH and 6 with PPH, pulmonary arterial pressure was measured by cardiac catheterization concomitantly. There were no significant differences in 1/R and pulmonary arterial pressure between the two groups when PH was diagnosed for the first time. In the PPH group, the mean period of follow-up study was 25.3 months and all of the patients died during that period. In SLE-PH group, the mean period of follow-up study was 50.6 months, and only 3 patients (43%) died during that period. No patients in the PPH group showed improvement in 1/R, but 3 patients with SLE-PH improved in 1/R during a long follow-up period (60, 96 and 103 months respectively). Thus, the prognosis for SLE-PH was better than that for PPH, and there were some differences in the course and worsening behavior of PH in SLE-PH compared with that in PPH during the long-term follow-up study with reference to the echocardiographic investigation using 1/R value.

Adolescent↗
PubMed1991

[A remarkable effect of K-18 (IgG-melphalan complex) in a case of RAEB with hypoplastic marrow].

A 63-year-old male with refractory anemia with excess of blasts (RAEB) and hypoplastic marrow was treated with K-18 (240 mg/day P.O.). On admission, peripheral blood revealed pancytopenia. Bone marrow specimen revealed severe hypocellularity with 18.9% of the blast cells. Ten months later, the blast cells in the bone marrow decreased to 3.8%, and complete remission (CR) was obtained. CR was eight weeks. Duration of response (CR + PR) continued for about eight months. K-18 is an antitumor agent with minimal side effects, and seems to be effective for RAEB with hypoplastic marrow.

Anemia, Refractory, with Excess of Blasts↗
PubMed1991

[Pituitary apoplexy with localized hematoma in the suprasellar region].

The authors report a case of a patient with a pituitary tumor, in which pituitary apoplexy occurred only in the suprasellar part of the tumor. A 26-year-old woman suffered from abrupt worsening of vision and headache. A CT scan showed a dumb-bell-shaped tumor extending to the suprasellar region, in which an irregularly shaped low density area suggesting a liquidized hematoma was seen. The rapid worsening of her symptoms was highly indicative of pituitary apoplexy. The first operation was performed through the transsphenoidal route. There was no evidence of intratumoral hematoma in the intrasellar tumor, which could be removed successfully. However, the suprasellar mass could not be reached because of the hardness of the diaphragma sellae and the presence of a normal pituitary gland. MRI and CT cisternography after this first operation showed a narrow opening of the diaphragma sellae. The second operation using right frontotemporal craniotomy disclosed a suprasellar mass, which consisted of an old hematoma and a necrotic tumor. The tumor was sub-totally removed. The patient's visual acuity improved after the second operation. Although transsphenoidal surgery is the treatment of choice in patients with pituitary apoplexy, the selection of the surgical route should be made only after careful neuroradiological evaluation with regard to the extrasellar extension of the tumor.

Adenoma↗
PubMed1990

Structure and expression of tomato mitochondrial genes coding for tRNA(Cys) (GCA), tRNA(Asn) (GUU) and tRNA(Tyr) (GUA): a native tRNA(Cys) gene is present in dicot plants but absent in monocot plants.

The nucleotide sequences of tRNA(Asn) (GUU) and tRNA(Tyr) (GUA) genes from tomato mitochondria and their flanking regions have been determined. The tomato mitochondrial tRNA(Asn) gene is located 2.1 kb downstream from the tRNA(Cys) gene reported previously (Izuchi and Sugita 1989) and shows a nearly complete identity with the corresponding chloroplast gene. The tRNA(Tyr) gene, which shows only 73% homology with the corresponding chloroplast gene, has to be considered a "native" mitochondrial tRNA gene and is 535 bp from the "chloroplast-like" tRNA(Asn) gene on the same strand. Northern hybridization analysis revealed that the three tRNA genes are transcribed in tomato mitochondria. Southern hybridization analysis of tomato, sugar beet. rice and wheat mitochondrial DNAs, with oligonucleotide probes for mitochondrial or chloroplast tRNA genes, demonstrated that the mitochondrial tRNA(Cys) gene found in tomato is present in dicot plants but not in monocots. On the other hand, a chloroplast-like tRNA(Cys) gene exists in monocot plants.

Base Sequence↗
PubMed1990

Feline herpesvirus type 1 glycoproteins eliciting virus neutralizing and hemagglutination-inhibiting antibodies.

Monoclonal antibodies (MoAbs) to feline herpesvirus type 1 (FHV-1) were produced to identify the virus-specified immunogenic proteins. When antigens recognized by the MoAbs were investigated by immunoblot and immunoprecipitation assays using FHV-1-infected cell lysate, four groups of immunogenic proteins were identified. MoAbs directed against 60 kDa, 113 kDa, and 143 kDa/108 kDa glycoproteins had virus neutralizing activities, but those against 170 kDa protein did not. Furthermore, MoAbs to the 60 kDa glycoprotein also showed hemagglutination-inhibition activity, indicating that this glycoprotein might be the hemagglutinin.

Animals↗
PubMed1990

Immunological relationship between feline herpesvirus type 1 (FHV-1) and canine herpesvirus (CHV) as revealed by polyvalent and monoclonal antibodies.

Polyvalent and monoclonal antibodies were used to demonstrate serological and antigenic relationships between feline herpesvirus type 1 (FHV-1) and canine herpesvirus (CHV). Using virus neutralization tests, enzyme-linked immunosorbent and indirect immunofluorescence assays, and immunoblotting analysis, reciprocal cross-reactivities to the heterologous virus were observed with some polyvalent and monoclonal antibodies. One monoclonal antibody against CHV neutralized FHV-1 infectivity and one monoclonal antibody against FHV-1 inhibited the hemagglutination activity of CHV as well as FHV-1-infected mouse serum. The major cross-reacting proteins were identified as the 143/108 kDa and 60 kDa glycoproteins of FHV-1 and the 145/112 kDa and 41 kDa glycoproteins of CHV. Previously, we have identified the 60 kDa and 41 kDa glycoproteins as the hemagglutinins of FHV-1 and CHV, respectively. The present results indicated the presence of shared antigenic determinants among these proteins.

Antibodies, Monoclonal↗
PubMed1990

Quantification of feline immunodeficiency virus in a newly established feline T-lymphoblastoid cell line (MYA-1 cells).

A quantitative method for analysis of feline immunodeficiency virus (FIV) was established by the indirect immunofluorescence (IF) test using MYA-1 cells infected with the serially diluted viruses. When we compared this method with the reverse transcriptase (RT) activity assay, the quantitative analysis by the indirect IF test was more sensitive than that by RT activity assay. The relationship between TCID50 measured by the indirect IF test and RT activity was linear. However, the RT activity assay was not suitable for measurement of low amounts of FIV in the supernatants of FIV-infected cultures.

Animals↗
PubMed1990

Isolation and characterization of rainbow trout C-reactive protein.

An acute phase serum component, C-reactive protein (CRP), was isolated from the sera of rainbow trout (Salmo gairdneri). The isolation was based on its calcium-dependent binding affinity for pneumococcal C-polysaccharide (CPS) according to the isolation procedure of human C-reactive protein. In SDS-PAGE, the nonreduced CRP showed two subunits with molecular weights of 43,700 and 26,600, respectively, at a molar ratio of 1:1. The reduced CRP showed a single subunit of 26,600. The molecular weight of the native protein was estimated as 66,000 by native gradient PAGE and 81,400 by sedimentation equilibrium analysis using ultracentrifugation. The antigenic determinant on CPS-reactive site was destroyed by periodate oxidation, indicating that rainbow trout CRP is a glycoprotein. CRP levels in rainbow trout serum measured by the CPS-ELISA procedure showed that the rainbow trout CRP could behave as an acute phase reactant, following experimental infection with the fish pathogen Vibrio anguillarum.

Amino Acids↗
PubMed1990

Development of an implantable motor-driven assist pump system.

A motor-driven artificial pump and its transcutaneous energy transmission (TET) system have been developed. The artificial pump consists of a high-speed dc brushless motor driving a ball screw and magnetic coupling mechanism between the blood pump and ball screw. The ball screw transfers high-speed rotary motion into low-speed rectilinear motion by a single component. Magnetic coupling enables active blood filling without applying an excess negative pressure to the pump. The transcutaneous transformer is formed from a pair of concave/convex ferrite cores. This design minimizes lateral motion of the external core. Information on motor voltage is transmitted through the skin by infrared pulses. The motor voltage is regulated by controlling the duty ratio of the square pulse supplied to the primary coil. Pump flow of 5.6 l/min was obtained with a mean outlet pressure of 100 mmHg at a drive rate of 100 bpm under preload of 15 mmHg. The performance of synchronous pumping has been very satisfactory. Continuous pumping was maintained by the backup battery in the case of interruption of TET. 24 W were transmitted by TET system with 78 percent of efficiency. Temperature rise of the internal core was 0.2 C. The developed system is promising as an implantable assist pump system.

Animals↗
PubMed1990

Detection of common flagella antigen in Bacillus cereus by monoclonal antibody.

Bacillus cereus has been classified into 23 types by immunochemical analyses of flagella antigen, but a common antigenic determinant of flagella had not been determined. When the immunochemical method of classification had changed from "agglutination method" to "enzyme-linked immunosorbent assay (ELISA)," the cross-reactivity between each flagella type was increased. These results indicated that the application of ELISA method would enable detection of the common antigenic determinant of B. cereus. Therefore, we attempted to make monoclonal antibody against common flagella antigen that could be detected by ELISA. Monoclonal antibody provided was specific for B. cereus (H-1 to H-23) and did not show the cross-reactivity with Escherichia coli NIH and Bacillus subtilis.

Antibodies, Bacterial↗