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Biomedical subjects

K Itoh

Publications and source records attributed to K Itoh.

At least 235 records · Page 13Linked to original sources
PubMed2000

Expression of the SART1 tumor rejection antigen in renal cell carcinoma.

We have previously described the SART1 gene, which encodes both the SART1(259) antigen expressed in the cytosol of the majority of squamous cell carcinomas and some adenocarcinomas and the SART1(800) antigen expressed in the nucleus of the majority of proliferating cells. The SART1(259) antigen is recognized by HLA-A24 and A26-restricted cytotoxic T lymphocytes (CTLs). The present study investigated the expression of these two antigens in renal cell carcinomas (RCCs) in order to identify an appropriate molecule for use in specific immunotherapy for RCC patients. These two antigens were detected in all RCC cell lines and cells of the primary cultures of the RCCs tested. Further, they were detectable in cells of the primary cultures of non-tumorous kidney tissues. In contrast to these cultured cells, SART1(259) was detectable in only a few uncultured RCC tissues (5/20, 25%) and was undetectable in non-tumorous kidney tissues. SART1(800) was also scarcely detectable in uncultured RCC tissues (3/20, 15%) and non-tumorous kidney tissues (4/20, 20%). HLA-A2402-restricted and tumor-specific CTL (KE4-CTL) used for the cloning of the SART1 gene showed significant levels of cytotoxicity to both the cells from the RCC cell line and the cells from the primary cultures of RCC tissues, but did not lyse any normal cells, including cells from the primary cultures of non-tumorous kidney tissues. The SART1-derived peptide at positions 690-698 induced HLA-A24 restricted CTLs cytotoxic to RCC cells from peripheral blood mononuclear cells (PBMCs) of RCC patients. Therefore, the SART1 peptide could be an appropriate molecule for use in peptide-based specific immunotherapy for RCC patients.

Adult↗
PubMed2000

Neuronal damage of the substantia nigra in HIV-1 infected brains.

Extrapyramidal motor disorders are frequently noted in HIV-1-infected patients. In the present study, the substantia nigra was analyzed morphometrically to detect neuronal changes which might contribute to the pathogenetic mechanisms causing extrapyramidal motor dysfunction in HIV-1-infected patients. The numerical density and the size of pigmented, non-pigmented small, and non-pigmented large neurons in four nuclei of the substantia nigra pars compacta (antero-medial, antero-intermediolateral, postero-lateral, and postero-medial nuclei) in HIV-1-infected patients and in age-matched normal controls were determined. In HIV-1-infected brains, the numerical density of total neurons (i.e., pigmented and non-pigmented) as well as of pigmented neurons was significantly decreased, whereas that of non-pigmented neurons was not significantly changed in all investigated nuclei of the substantia nigra as compared to normal controls. A specific pattern of increase and decrease of nonpigmented large and non-pigmented small neurons was observed. The size of total neurons (pigmented and nonpigmented neurons) and of pigmented neurons was significantly reduced in all investigated nuclei of HIV-1-infected brains. The results suggest that neuronal degeneration in the substantia nigra commonly occurs and may be related to extrapyramidal symptoms in HIV-1-infected patients.

AIDS Dementia Complex↗
PubMed2000

Transtrochanteric rotational osteotomy for osteonecrosis of the femoral head with preoperative superselective angiography.

A prospective radiologic and scintigraphic study was made of 15 joints in 12 patients who underwent transtrochanteric rotational osteotomy of the femoral head after identifying by preoperative superselective angiography which arteries should be preserved during surgery. The preoperative superselective angiography revealed that the blood supply to the femoral head was provided by the medial femoral circumflex artery in 12 joints and a branch of the internal iliac artery in 3 joints. These nutrient arteries were preserved during surgery. At the follow-up examination made after at least 2 years, there were no cases of collapse of the new femoral head weight-bearing site, and also there were no cases with a large cold area in the femoral head on the scintigram obtained 2 months postoperatively. For this operative procedure, the nutrient arteries of the femoral head should be confirmed by preoperative superselective angiography, and it is essential that these arteries be preserved during surgery.

Adolescent↗
PubMed2000

Small guanosine triphosphatase Rho/Rho-associated kinase as a novel regulator of intracellular redistribution of lysosomes in invasive tumor cells.

To investigate the role of RhoA on the intracellular membrane dynamics of lysosomes in rat hepatoma cells (MM1), we analyzed the localization of lysosomal aspartic proteinase cathepsin D by confocal immunofluorescence microscopy in the dominant active RhoA-transfected cells. Here we show that the transfection of the dominant active form of human small guanosine triphosphatase (GTPase) RhoA in MMI cells, a highly invasive cell line, causes the redistribution and spreading of small punctate structures stained for cathepsin D throughout the cytoplasm. We found that the microtubule organization was markedly different in the two cell lines: uniformly developed and polymerized microtubule filaments were seen in the mock transfectants; however, the dynamic organization of microtubules was less pronounced in the active RhoA transfectants. Furthermore, we found for the first time that a selective inhibitor of Rho-associated kinase (p160ROCK), Y-27632, impeded the subcellular spreading of cathepsin D staining and promoted reclustering of cathepsin D toward the perinuclear region in the active RhoA-transfected cells. To our knowledge, this is the first indication that the RhoA/ROCK-mediated signaling pathway is involved in the intracellular membrane dynamics of lysosomes by regulating the cytoskeletal microtubule organization as well as the actin cytoskeletons.

Actins↗
PubMed2000

Altered vascular response to acetylcholine in conditions of endothelial damage in the isolated perfused rat stomach.

To examine the mechanism of stress ulcers and the relation between endothelium derived relaxing factor (EDRF)/NO and gastric mucosal blood flow (GMBF), we used an isolated perfused rat stomach model and studied the effects of an autonomic nerve activator, nitric oxide synthase (NOS) synthesis, and an EDRF/NO inhibitor on gastric blood circulation. Rats were divided into four groups according to pretreatment: (1) control; (2) those given gossypol, a drug provoking endothelial cell damage; (3) those given L-N monomethylarginine (L-NMMA), a specific inhibitor of EDRF/NO; and (4) those subjected to water-immersion stress. Using this model we collected the perfusion fluid from the portal vein at various time points. After administration of acetylcholine, the perfusion flow increased in the control group, but perfusion flow showed no change in the L-NMMA group. On the other hand, the perfusion flow decreased in the gossypol and water-immersion stress groups. The perfusion fluid from the control group contained cGMP, but this substance was absent in the perfusion fluid of the other experimental groups. We considered that increased cGMP in the fluid came from endothelial cells. We presume that the presence of EDRF/NO is essential for the control of GMBF and that from the viewpoint of gastric ulcers, the lack of EDRF/NO may be an important factor in the decrease of GMBF in the early stages of water-immersion stress.

Acetylcholine↗
PubMed2000

Pancreatic lesions in von Hippel-Lindau syndrome: the coexistence of metastatic tumors from renal cell carcinoma and multiple cysts.

Multiple cysts and benign cystadenomas of the pancreas have been documented occasionally in von Hippel-Lindau syndrome (HLS); however, the malignant involvement of the pancreas in HLS is very rare. We report a case of HLS in which metastatic tumors from renal cell carcinoma (RCC) coexisted with multiple cysts in the pancreas. A 22-year-old woman with a history of HLS had undergone a partial resection of the left kidney for RCC 3 years earlier, at which time a solid mass in the pancreatic tail and multiple pancreatic cysts were also incidentally detected by computed tomography. Over the following 3 years, the mass enlarged slightly, thus raising suspicions that it might be a primary neoplasm of the pancreas. She was referred to the Department of Surgery and Surgical Basic Science to undergo surgery. In addition to the tumor in the pancreatic tail, however, further tumors in the pancreatic head were also disclosed by preoperative celiac arteriography and intraoperative palpation and ultrasonography. A distal pancreatectomy was performed, because the enucleation of all the tumors in the pancreatic head was technically impossible and because the patient declined a total pancreatectomy. A histologic examination of the mass in the pancreatic tail revealed metastatic RCC. This case emphasizes that metastatic disease should be included in the differential diagnosis when evaluating the pancreas in a patient with HLS.

Adult↗
PubMed2000

Enzymatic corrections for cells derived from Fabry disease patients by a recombinant adenovirus vector.

Fabry disease is an X-linked inherited metabolic disorder caused by a deficiency of alpha-galactosidase (alpha-gal), resulting in the accumulation of ceramide trihexoside (CTH) in body fluids and in many organs and tissues. We constructed a recombinant adenovirus with a human alpha-gal cDNA (AxCAG alpha-gal), and transfected this vector to skin fibroblasts from Fabry patients. Transfected cells expressed high amounts of alpha-gal in their cytoplasm, and a high level of alpha-gal activity was detected in the medium. The accumulated CTH in the fibroblasts disappeared 3 days after infection. The secreted alpha-gal also eliminated the accumulated CTH from uninfected patient's cells. The enzyme may be taken up through mannose-6-phosphate receptors, as the addition of mannose-6-phosphate to the medium completely inhibited the uptake of the enzyme. The infected cells continued to express alpha-gal for more than 10 days. These results suggest that AxCAG alpha-gal could be used as enzyme replacement gene therapy for Fabry disease.

Adenoviridae↗
PubMed2000

Structural and functional study of K453E mutant protective protein/cathepsin A causing the late infantile form of galactosialidosis.

To clarify the molecular basis of the late infantile form of galactosialidosis, we characterized a defective protective protein/cathepsin A (PPCA) gene product with the K453E mutation newly found in an Arabic patient with this disease. Immunocytochemical, expression, and metabolic studies revealed that the precursor PPCA was synthesized but not processed to the mature form, and it was degraded in the mutant. A structural model of the mutant PPCA was constructed by amino acid substitution of 453glutamic acid for lysine in the crystal structure of the wild type PPCA precursor reported. The results show that the K453E mutation is located at the dimer interface of the PPCA and reduces the hydrogen bond formation in the dimer. This structural change may cause instability of the PPCA dimer.

Amino Acid Substitution↗
PubMed2000

Molecular and structural studies of Japanese patients with sialidosis type 1.

To gain insight into the pathogenesis of sialidosis type 1, we performed molecular investigations of two unrelated Japanese patients. Both of them are compound heterozygotes for base substitutions of 649G-to-A and 727G-to-A, which result in amino acid alterations V217M and G243R, respectively. Using homology modeling, the structure of human lysosomal neuraminidase was constructed and the structural changes caused by these missense mutations were deduced. The predicted change due to V217M was smaller than that caused by G243R, the latter resulting in a drastic, widespread alteration. The overexpressed gene products containing these mutations had the same molecular weight as that of the wild type, although the amounts of the products were moderately decreased. A biochemical study demonstrated that the expressed neuraminidase containing a V217M mutation was partly transported to lysosomes and showed residual enzyme activity, although a G243R mutant was retained in the endoplasmic reticulum/Golgi area and had completely lost the enzyme activity. Considering the data, we surmise that the V217M substitution may be closely associated with the phenotype of sialidosis type 1 with a late onset and moderate clinical course.

Adult↗
PubMed2000

Decreased expression of mouse Rbm3, a cold-shock protein, in Sertoli cells of cryptorchid testis.

Physiological scrotal hypothermia is necessary for normal spermatogenesis and fertility in mammals. Human RNA binding motif protein 3 (RBM3) is structurally highly similar to the cold-inducible RNA-binding protein (Cirp), and both mRNAs are induced in human cells at the scrotal temperature (32 degrees C). We report here the cloning of mouse Rbm3 cDNA, which encoded an 18-kd protein with 94% identity in amino acid sequence to that of human RBM3. In the testis of adult mice, Rbm3 mRNA and protein were detected in Sertoli cells, but not germ cells, of seminiferous tubules at all stages. The expression was not observed in Sertoli cells of fetuses, but was observed in newborn and older mice. In the TAMA26 mouse Sertoli cell line, the Rbm3 expression level was increased or decreased within 12 hours after temperature shift from 37 degrees C to 32 degrees C or 39 degrees C, respectively. In contrast to Cirp, the cold-induced growth suppression of TAMA26 cells was not affected by suppression of the Rbm3 expression. When mouse testis was exposed to heat stress by experimental cryptorchidism, the level of Rbm3 was decreased in Sertoli cells. Rbm3 may play important roles distinct from those played by Cirp in spermatogenesis and cryptorchidism by regulating the gene expression in Sertoli cells.

Amino Acid Sequence↗
PubMed2000

Improved detection of echo signals from inside bone.

The purpose of the study was to obtain useful information for diagnosing internal abnormalities of bones by ultrasound. We fabricated a transmitting and receiving system mainly targeting the bone and an image processing system using a computer, and studied the attenuation of ultrasound in animal bone (in vitro). The average value was about 37 dB. The examination was able to determine successfully the proper dynamic range for detection, and a B-mode image of the inside of the bone could be displayed. Here we describe a new transmitting and receiving system developed to improve the detection of echo signals from inside bones. In this method, two kinds of high sensitivity transducer were made as follows: (1) 5 HMz frequency, 6.5 mm diameter; (2) 10 HMz frequency, 13 mm diameter. By using this method, detectability of the echo signals can be increased more than with the former system. The results showed that the structure of the bones could be clearly seen in the B-mode images.

Animals↗
PubMed2000

Anionic trypsin from chum salmon: activity with p-amidinophenyl ester and comparison with bovine and Streptomyces griseus trypsins.

An anionic trypsin from pyloric caeca of chum salmon (Oncorhynchus keta) was purified by ammonium sulfate and acetone fractionation followed by affinity chromatography, gel-filtration, and DEAE-anion exchange chromatography. The apparent molecular mass was about 24 kDa as determined by SDS-PAGE. The anionic chum salmon trypsin was moderately active toward esterase substrates such as tosyl-L-arginine methyl ester and tosyl-L-lysine methyl ester. Its amidase activity for benzoyl-L-arginine p-nitroanilide was comparative to those of bovine and Streptomyces griseus trypsins. Kinetic characteristics of anionic chum salmon, bovine, and Streptomyces griseus trypsins toward inverse substrate (p-amidinophenyl ester) were compared. Inverse substrate behaved as a specific substrate for anionic chum salmon trypsin with specific binding, efficient acylation, and relatively slow deacylation.

Amides↗
PubMed2000

Isolation of Campylobacter species from zoo animals and polymerase chain reaction-based random amplified polymorphism DNA analysis.

A total of 104 fecal specimens from 30 mammals, 12 birds, and 3 reptiles at the Phoenix Zoological Gardens, Miyazaki City, Japan, were examined for the presence of Campylobacter species. All the animals examined were healthy with no fecal abnormality. Twenty-three (22.1%) thermophilic campylobacters, (9 C. jejuni, 11 C. hyointestinalis, 2 C. coli, and 1 C. lari), were isolated from 11 animals (7 mammals and 4 birds). C. jejuni and C. hyointestinalis were the predominant species isolated from these zoo animals and C. hyointestinalis was isolated frequently from simians. As selective media influence the numbers and species of campylobacters isolated, the agar medium was not supplemented with cephalothin. Campylobacters were isolated most frequently when a combination of enrichment culture and selective agar plating was performed at 42 degrees C. For the epidemiological study, a polymerase chain reaction (PCR)-based randomly amplified polymorphic DNA (RAPD) method was used as a tool to detect the heterogeneity of amplified DNAs of Campylobacter spp. isolated from zoo animals. The two arbitrary primers used in this study enabled even closely related strains of the same Campylobacter spp. to be differentiated. RAPD analysis revealed considerable diversity among the strains, suggesting that the transmission of Campylobacter spp. among animals in a defined area occurred through different mechanisms. Examination of the genotypic diversity among the multiple clones from the same host also revealed differences between clones. These results demonstrate that campylobacter populations in zoo animals are highly divergent.

Animals↗
PubMed2000

The house musk shrew (Suncus murinus): a unique animal with extremely low level of expression of mRNAs for CYP3A and flavin-containing monooxygenase.

Expression of drug-metabolizing enzymes including cytochrome P450 (CYP) and flavin-containing monooxygenase (FMO) in various tissues of Suncus murinus (Suncus) were examined. Northern blot analysis showed that mRNAs hybridizable with cDNAs for rat CYP1A2, human CYP2A6, rat CYP2B1, human CYP2C8, human CYP2D6, rat CYP2E1, human CYP3A4 and rat CYP4A1 were expressed in various tissues from Suncus. The mRNA level of CYP2A in the Suncus lung was very high. Furthermore, it was found that the level of CYP2A mRNA in the Suncus lung was higher compared to the Suncus liver. The expression level of mRNA hybridizable with cDNA for human CYP3A4 was very low. The presence of CYP3A gene in Suncus was proven by the induction of the CYP with dexamethasone. Very low expression levels of mRNAs hybridizable with cDNAs for rat FMO1, rat FMO2, rat FMO3 and rat FMO5 were also seen in Suncus liver. No apparent hybridization band appeared when human FMO4 cDNA was used as a probe. The hepatic expression of mRNAs hybridizable with cDNAs for UDP-glucuronosyltransferase 1*6, aryl sulfotransferase, glutathione S-transferase 1, carboxyesterase and microsomal epoxide hydrolase in the Suncus were observed. These results indicate that the Suncus is a unique animal species in that mRNAs for CYP3A and FMO are expressed at very low levels.

Animals↗
PubMed2000

Microcapsulated parathyroid tissue in vitro.

Ideally, microcapsules will make it possible to transplant parathyroid tissue for allo- and xenotransplantation in hypoparathyroid patients. In this study, parathyroid tissues capsulated by polyelectrolyte complex were evaluated in vitro. Hormone secretion ability was significantly (P < 0.001) greater in sediment than in supernatant. There was no difference in hormone secretion ability between the parathyroid tissue thawed at room temperature and the tissue thawed in a bath at 37 degrees C. Both non-capsulated and capsulated parathyroid tissues were incubated for three weeks. The ability of capsulated parathyroid to secrete hormones in vitro was reduced gradually and disappeared within three weeks. There are still several problems to be solved before the clinical application of parathyroid allotransplantation using microcapsulation.

Cryopreservation↗
PubMed2000

Dose-escalation study of CHOP with or without prophylactic G-CSF in aggressive non-Hodgkin's lymphoma.

BACKGROUND: CHOP is accepted as the gold standard for first line chemotherapy of aggressive non-Hodgkin's lymphoma (NHL). A dose-escalation study of CHOP was conducted to determine the maximal tolerated dose (MTD) and toxicity profile of CHOP at three-week intervals with or without prophylactic recombinant human granulocyte colony-stimulating factor (rHuG-CSF) in patients with aggressive NHL. PATIENTS AND METHODS: The doses of drugs were escalated from 50 mg/m2 to 70 mg/m2 for doxorubicin and from 750 mg/m2 to 2250 mg/m2 for cyclophosphamide, with conventional doses of vincristine and oral prednisolone. After the MTD was determined without rHuG-CSF, dose escalation was conducted with prophylactic rHuG-CSF. RESULTS: Thirty-three patients with NHL were enrolled into the study. The MTD without prophylactic rHuG-CSF was 70 mg/m2 of doxorubicin and 1250 mg/m2 of cyclophosphamide, with neutropenia as a dose-limiting toxicity. The MTD with prophylactic rHuG-CSF was 70 mg/m2 of doxorubicin and 2250 mg/m2 of cyclophosphamide. The overall response rate was 100% (76% complete response and 24% partial response). Progression-free survival and overall survival at five years were 45% and 66%, respectively. CONCLUSIONS: Significant dose escalation of doxorubicin and cyclophosphamide was feasible with prophylactic rHuG-CSF. The efficacy of dose-escalated CHOP should be compared with that of standard CHOP.

Adolescent↗