Biomedical subjects

T Kitamura

Publications and source records attributed to T Kitamura.

At least 541 records · Page 30Linked to original sources

PubMed1990

Diagnosis of hepatic cavernous hemangioma by fine needle aspiration biopsy under ultrasonic guidance.

Percutaneous aspiration biopsy of the liver using a heparinized 22-gauge needle was performed under ultrasonic guidance in 11 patients with hepatic cavernous hemangioma. Ten (91%) of 11 biopsy specimens obtained were cytologically diagnostic for hemangioma. No indications of malignancy were found. There was no relation between the cytological diagnosis and the location, size, or ultrasonographic findings. No complications were encountered. These findings indicate that cytological examination of the liver by fine needle aspiration biopsy is useful in diagnosing hepatic cavernous hemangioma of any size and in any location, provided optimal route to the lesions is chosen.

Aged↗

PubMed1990

Removal of HIV antigens and HIV-infected cells in vitro using immunomagnetic beads.

Human anti-HIV antibody-coated magnetic beads and magnetic particle concentrators were used to eliminate HIV antigens and the infected cells in vitro. Fifty micrograms/ml of the antibody coated on 30 mg/ml of tosyl-activated beads, and 10 min of reaction time between the antigens and the immunobeads were sufficient to eliminate the virus antigens from phosphate buffered saline, serum and peripheral blood. HIV-infected cells were eliminated in vitro, but not completely. This method will be useful in eliminating viral antigens and infected cells from clinical material such as blood and blood products.

Cell Separation↗

PubMed1990

Cloning and expression of a gene encoding an interleukin 3 receptor-like protein: identification of another member of the cytokine receptor gene family.

Using a monoclonal antibody to the interleukin 3 (IL-3) receptor (anti-Aic2), we isolated a cDNA (AIC2B) from a mouse mast cell line which is homologous to the previously characterized gene for the IL-3 receptor (AIC2A). This cDNA encodes a polypeptide of 896 amino acid residues and has 91% amino acid sequence identity with the IL-3 receptor. A consensus sequence defining an additional cytokine receptor family is present in this clone. Compared to the AIC2A clone, the AIC2B cDNA encodes a protein with amino acid substitutions, insertions, and deletions dispersed throughout the entire protein. Oligonucleotide probes specific for each cDNA hybridized with different genomic fragments, indicating that the AIC2A and AIC2B proteins are encoded by two distinct genes. Fibroblasts transfected with the AIC2B cDNA expressed the protein at the cell surface as determined by binding with the anti-Aic2 antibody but did not bind IL-3 or other cytokines, including IL-2, IL-4, granulocyte-macrophage colony-stimulating factor, erythropoietin, and IL-9 (p40) at concentrations between 1 and 10 nM. An S1 nuclease protection assay was used to discriminate between the AIC2A and AIC2B transcripts. We found that the AIC2B gene was coexpressed with the AIC2A gene. These results suggest a potential involvement of AIC2B in cytokine signal transduction.

Amino Acid Sequence↗

PubMed1990

Molecular cloning of a second subunit of the receptor for human granulocyte-macrophage colony-stimulating factor (GM-CSF): reconstitution of a high-affinity GM-CSF receptor.

Using the mouse interleukin 3 (IL-3) receptor cDNA as a probe, we obtained a homologous cDNA (KH97) from a cDNA library of a human hemopoietic cell line, TF-1. The protein encoded by the KH97 cDNA has 56% amino acid sequence identity with the mouse IL-3 receptor and retains features common to the family of cytokine receptors. Fibroblasts transfected with the KH97 cDNA expressed a protein of 120 kDa but did not bind any human cytokines, including IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, cotransfection of cDNAs for KH97 and the low-affinity human GM-CSF receptor in fibroblasts resulted in formation of a high-affinity receptor for GM-CSF. The dissociation rate of GM-CSF from the reconstituted high-affinity receptor was slower than that from the low-affinity site, whereas the association rate was unchanged. Cross-linking of 125I-labeled GM-CSF to fibroblasts cotransfected with both cDNAs revealed the same cross-linking patterns as in TF-1 cells--i.e., two major proteins of 80 and 120 kDa which correspond to the low-affinity GM-CSF receptor and the KH97 protein, respectively. These results indicate that the high-affinity GM-CSF receptor is composed of at least two components in a manner analogous to the IL-2 receptor. We therefore propose to designate the low-affinity GM-CSF receptor and the KH97 protein as the alpha and beta subunits of the GM-CSF receptor, respectively.

Amino Acid Sequence↗

PubMed1990

Defective ATP-dependent bile canalicular transport of organic anions in mutant (TR-) rats with conjugated hyperbilirubinemia.

TR- mutant Wistar rats secrete markedly fewer organic anions other than bile acids from the liver into the bile than do control rats. Fluorescence-image analysis of isolated normal and TR- hepatocyte "doublets", which retain a bile canaliculus between them, revealed that normal hepatocytes readily transport a fluorescent bile acid (fluorescein isothiocyanate glycocholate) and a nonbile acid organic anion (carboxydichlorofluorescein diacetate) into the canaliculus. Hepatocyte doublets from TR- rats also transported fluorescein isothiocyanate glycocholate normally, but transport of carboxydichlorofluorescein diacetate into the canaliculus was negligible. Vesicles derived from the canicular domain of the plasma membrane of hepatocytes (CMV) from control and TR- rats were used to characterize the transport process for 35S-labeled bromosulphthalein and 35S-labeled bromosulphthalein glutathione, which represent nonbile acid organic anions. CMV from normal rat hepatocytes had an ATP- and temperature-dependent, saturable transport process for these 35S-labeled compounds that was absent in CMV from TR- rats. CMV from TR- rats retained normal ATP-dependent transport of daunomycin, and immunologic blots with a monoclonal antibody against the multidrug resistance gene product, P-glycoprotein, revealed no difference between normal and TR-CMV. These studies reveal that the bile canaliculus in normal rats contains an ATP-dependent organic anion transport system that is functionally absent in TR- mutant rats. The defect in TR- mutant rats is phenotypically similar to that seen in mutant Corriedale sheep and in the Dubin-Johnson syndrome in man.

Adenosine Triphosphate↗

PubMed1990

High incidence of urinary JC virus excretion in nonimmunosuppressed older patients.

Urine specimens from 120 patients attending urologic clinics were screened by blot hybridization for the presence of a polyomavirus DNA. Detected viral DNA was then identified as BK or JC by fine restriction enzyme analysis. BK and JC viral DNA was found in 5 (4%) and 35 (29%) patients, respectively. Detection rates were compared among three age groups: 0-29, 30-59, and 60-89 years. Detection of JC viral DNA increased with age and reached the highest value (45%) in the group aged 60-89 years. For BK viral DNA a correlation between detection and age was not clear because the rate of detection was low, although the highest rate (9%) occurred in the oldest group. To confirm the active urinary excretion of polyomavirus DNA in older patients, urine specimens from 23 patients (60-90 years) treated at an internal medicine clinic were examined for viral DNA. BK and JC viral DNA were in 2 (9%) and 12 patients (52%), respectively. These results suggest that JC virus is frequently reactivated in older individuals.

Adolescent↗

PubMed1990

Shorter size of transmembrane glycoprotein of an HIV-1 isolate.

An HIV-1 strain carrying a shorter form of the transmembrane glycoprotein (TM) with a mobility of 32 kD, named KB-1, was isolated from a Japanese male hemophiliac by coculture of his peripheral blood mononuclear cells (PBMCs) with MT-2 cells and adaption to TALL-1 cells. Another HIV-1 strain, named KB-2, was isolated from his seropositive spouse by coculture of her PBMCs with MT-2 cells. The KB-2 strain carried a TM of ordinary size, with a mobility of 41 kD. The KB-1 strain carrying a truncated form of the TM could replicate in MT-2, MT-4, TALL-1 and MOLT-4 cells. The KB-1 strain is a useful HIV-1 isolate for investigating the function of the cytoplasmic domain of the TM and the significance of the presence of an in-frame stop codon in HIV env gene.

Blotting, Western↗

PubMed1990

Inhibitory effect of novel 1-deoxynojirimycin derivatives on HIV-1 replication.

The effect of 11 derivatives of 1-deoxynojirimycin (DNM) on the replication of HIV-1 was studied. Compared with DNM, seven of them showed remarkable inhibition of HIV-1-induced syncytium formation at significantly low concentrations which were not cytotoxic. Two derivatives were found to markedly reduce the infectious virus yields from cell lines chronically infected with HIV. Analysis of HIV-1 envelope glycoproteins showed that the derivatives induced modification of the processing of not only gp120/160 but also the transmembrane glycoprotein gp41. The modification of the processing of the transmembrane glycoprotein gp41 might play an important role in the inhibition of virus replication at a step after the binding of gp120 to CD4. The enhanced anti-HIV activity of DNM derivatives reported here could increase the possibility of non-toxic therapeutic intervention in HIV infections.

1-Deoxynojirimycin↗

PubMed1990

On-line pressure estimation for a left heart assist device.

Long term measurement of blood pressures is essential for control of circulatory systems with artificial hearts or circulatory assist devices. Efforts to obtain reliable continuous direct measurements of blood pressures, however, have not been successful. This paper describes an on-line pressure estimation technique for use with a portable pneumatically driven left heart assist device. The on-line maximum likelihood algorithms are used for the estimation with the technique based on the use of physical models of the components of the driver and blood pump system. This technique estimates the inlet and outlet pressures of the blood pump. The directly measured driving air pressure and piston position of the pneumatic actuator are used for the estimation. In vitro and in vivo experiments were made to test the use of the on-line estimation technique. The results show successful linear correlations between the actual pressures and their estimates. This technique offers the following advantages: accurate pressure information for on-line control, accessibility to the transducers for recalibration, and noninvasive location of the transducers.

Algorithms↗

PubMed1990

Left atrial pressure controller design for an artificial heart.

This paper describes the application of a dynamic compensator technique to the left atrial controller design for use with a portable artificial heart drive system. The compensator is designed using a method in the field of multivariable control. This controller design is based on the physical models of the actuator and blood pump system. The analysis shows that there exists a minimal compensator with a dimension of one. The computer simulation demonstrates the acceptable, robust control performance of the left atrial pressure for a relatively small parameter variation of the vascular system model when all the poles of the closed-loop system are assigned to appropriate values.

Algorithms↗

PubMed1990

[Immunoglobulin components and anti-viral activities in bovine colostrum].

Bovine colostrum whey and immunoglobulins were prepared. Their characteristics and anti-viral activities were studied:IgG, IgA and IgM were found in bovine colostrum. Most IgG was polymerized. Although neutralization activities against bovine, simian and human rotaviruses existed, anti-human adenovirus antibody was not found. Effects on prophylaxis and treatment for rotavirus gastroenteritis were expected.

Animals↗

PubMed1990

3'-Azido-3'-deoxythymidine prevents induction of murine acquired immunodeficiency syndrome in C57BL/10 mice infected with LP-BM5 murine leukemia viruses, a possible animal model for antiretroviral drug screening.

Adult C57BL/10 mice (H-2b Fv-1b) inoculated with LP-BM5 murine leukemia virus develop a disease which has many features in common with human acquired immunodeficiency syndrome (AIDS), in particular abnormal lymphoproliferation and severe immunodeficiency. In the present study, we examined the possibility that this murine AIDS (MAIDS) model would be useful for evaluating antiretrovirus drugs in vivo through the use of a well-defined antiretrovirus drug, the reverse transcriptase (RT) inhibitor (H. Mitsuya, K.J. Weinhold, P.A. Furman, M.H. St. Claire, S. Nusinoff-Lehrman, R.C. Gallo, D. Bolognesi, D.W. Barry, and S. Broder, Proc. Natl. Acad. Sci. USA 82:7096-7100, 1985) 3'-azido-3'-deoxythymidine (AZT). We evaluated the effect of AZT treatment on de novo virus infection as well as on the induction of immunodeficiency by various parameters, including RT activity in serum, splenomegaly, proliferative responses against alloantigens and mitogens, soluble-antigen-presenting cell activity, and immunoglobulin G levels in serum. Our results demonstrated that AZT treatment of C57BL/10 mice infected with LP-BM5 murine leukemia virus efficiently prevented the induction of immunodeficiency if started at the time of virus inoculation. Starting AZT treatment 1 week later provided only a partial protective effect. Starting AZT treatment 2 weeks later was associated with suppression of RT activity in serum but no prevention of immunosuppression. This MAIDS model may allow rapid and cost-effective screening for antiretrovirus drugs targeted against retroviral functions shared between human AIDS and MAIDS, such as those encoded by gag, pol, or env.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Isolation of a possible archetypal JC virus DNA sequence from nonimmunocompromised individuals.

We molecularly cloned JC polyomavirus DNAs from urine samples of eight nonimmunosuppressed patients and two healthy individuals. The cloned viral DNAs all contained an archetypal regulatory sequence from which various regulatory sequences of JC polyomavirus isolates derived from patients with progressive multifocal leukoencephalopathy could have evolved by deletion and amplification.

Base Sequence↗

PubMed1990

Color Doppler flow imaging of liver tumors.

A differential diagnosis of liver tumors was attempted on the basis of the pattern of blood flow within and around tumors on color Doppler flow images. The study comprised 35 patients with liver mass lesions: 20 patients had hepatocellular carcinoma, six had hemangiomas, four had metastatic liver cancers, one had cholangiocellular carcinoma, one had focal fatty liver, and three had liver cysts. A basket pattern (a fine blood-flow network surrounding the tumor nodule) was observed in 15 (75%) of the 20 hepatocellular carcinomas. An image of vessels within the tumor (blood flow that runs into and branches within the tumor) was observed in 13 (65%) of the 20 hepatocellular carcinomas. These two findings were observed only in hepatocellular carcinomas; even when the tumor was smaller than 2 cm in diameter, these findings were observed frequently. In the patients with multiple hepatic metastases, a "detour" pattern (a dilated portal vein meandering around the tumor nodules) was observed. In three of the six hemangiomas, a "spot" pattern (color-stained dots or patches in the central region of the tumor) was seen. Our experience suggests that hepatocellular carcinomas have a characteristic appearance on color Doppler flow images.

Adenoma, Bile Duct↗

PubMed1990

Incidence of antibodies against human immunodeficiency virus, human T-cell lymphotropic virus type 1, hepatitis B virus, hemorrhagic fever with renal syndrome virus and Chlamydia in Tonga and western Samoa.

Among the populations of Tonga and Western Samoa, serum antibodies against human immunodeficiency virus or hemorrhagic fever with renal syndrome virus were not detected (0/904 and 0/192). No serum samples were considered to be positive for antibody against human T-cell lymphotropic virus type 1 (0/527). Hepatitis B antigen and antibody were found in 4% (8/192) and 47% (90/192), respectively. Chlamydia trachomatis IgG and C. psittaci IgG antibodies were detected in 39% (75/192) and 47% (91/192), respectively. The possibilities of the spread of human immunodeficiency virus and hemorrhagic fever with renal syndrome virus on the islands when the viruses invade from abroad were discussed.

Adolescent↗

PubMed1990

Effect of N-(3-phenyl-2-propenyl)-1-deoxynojirimycin on the lectin binding to HIV-1 glycoproteins.

The effect of N-(3-phenyl-2-propenyl)-1-deoxynojirimycin (ppDNM) on the lectin binding to HIV-1 glycoprotein was analyzed by using biotinylated lectins of various sugar specificities as probes. ppDNM potentially inhibited HIV-1-induced syncytium formation and viral infectivity of HIV-1 without cytotoxicity. The lectin binding assay showed that ppDNM treatment reduced Con A binding to gp120 of HIV-1.

1-Deoxynojirimycin↗

PubMed1990

Characterization and molecular features of the cell surface receptor for human granulocyte-macrophage colony-stimulating factor.

The receptors for human granulocyte-macrophage colony-stimulating factor (GM-CSF) on the surfaces of normal and leukemic myeloid cells were characterized using 125I-labeled bacterially synthesized GM-CSF. The binding was rapid, specific, time dependent, and saturable. Scatchard analysis of the 125I-GM-CSF binding to peripheral blood neutrophils indicated the presence of a single class of binding site (Kd = 99 +/- 21 pM; 2,304 +/- 953 sites/cell). However, for peripheral blood monocytes and two GM-CSF-responsive myeloid cell lines (U-937 and TF-1), the Scatchard plots were biphasic curvilinear, which were best fit by curves derived from two binding site model: one with high affinity (Kd1 = 10-40 pM) and the other with low affinity (Kd2 = 0.9-2.0 nM). For U-937 cells, the number of high-affinity receptors was 1,058 +/- 402 sites/cell and that of low-affinity receptors was estimated to be 10,834 +/- 2,396 sites/cell. Cross-linking studies yielded three major bands with molecular masses of 150 kDa, 115 kDa, and 95 kDa, which were displaced by an excess amount of unlabeled GM-CSF, suggesting 135-kDa, 100-kDa, and 80-kDa species for the individual components of the human GM-CSF receptor. These bands comigrated for different cell types including peripheral blood neutrophils, U-937 cells and TF-1 cells. In experiments using U-937 cells, only the latter two bands appeared to be labeled in a dose-dependent manner in a low-affinity state. These results suggest that the human GM-CSF receptor possibly forms a multichain complex.

Binding, Competitive↗

PubMed1990

[Therapy of hepatocellular carcinoma with UFT--clinical evaluation of its effect in the combination therapy with transcatheter arterial embolization or one shot therapy].

In 55 hepatocellular carcinoma patients treated with transcatheter arterial embolization or one shot therapy, the prognosis of patients treated with UFT (group A; n = 23) were historically compared with those of patients treated without UFT (group B; n=32). In group A, survival rate was 91.3% at 6 month; 67.5% at 1-year, 24.3% at 2-year, 24.3% at 3 year, in group B, 59.4% at 6-month, 37.5% at 1 year, 16.1% at 2-year. In these comparison, group A revealed significantly higher survival rate than group B. These results indicated that UFT was effective as maintenance therapy after transcatheter arterial embolization or one shot therapy with hepatocellular carcinoma.

Aged↗