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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 415 records · Page 23Linked to original sources
PubMed1998

Induction of cellular processes containing collagenase and retinoid by integrin-binding to interstitial collagen in hepatic stellate cell culture.

Cultured hepatic stellate cells were induced to elongate long, multipolar cellular processes by interstitial collagen gel used as a substratum, as compared to flattened or round cell shapes on polystyrene surface or on Matrigel containing the basement membrane components, respectively. The process induction was inhibited by several reagents as follows: (1) anti-integrin alpha2 antibody; (2) an oligopeptide, DGEA, an integrin-binding sequence in type I collagen molecule; (3) wortmannin, a phosphatidylinositol 3-kinase inhibitor. Protein tyrosine phosphorylation was enhanced throughout cells including cellular processes by culturing on type I collagen gel. Dual fluorescence staining showed that the core of the processes contained microtubules, whereas the periphery of the processes comprised fibrillar actin. Thus, the process extension was found to depend on integrin-binding to type I collagen fibres, followed by signal transduction and cytoskeleton assembly. The cellular processes included interstitial collagenase and vitamin A-containing lipid droplets. The lipid droplets and vitamin A-autofluorescence were increased by retinyl acetate addition to the culture medium, suggesting an important role of processes in hepatic stellate cell function.

Androstadienes↗
PubMed1998

Whole body autoradiographic study on the distribution of 14C-D-serine administered intravenously to rats.

The distribution of radioactivities in rats following intravenous administration of 14C-D- or -L-serine was investigated by whole body autoradiography. The radioactivities were distributed throughout the whole body in both cases with the greatest amount being found in the pancreas. D- and L- Serine levels in the pancreas were determined by high-performance liquid chromatography with a chiral column which revealed, for the first time, the existence of D-serine in the rat pancreas (12.6 +/- 7.90 nmol/g wet tissue) together with a much higher concentration (924 +/- 116 nmol/g) of L-serine. The results suggested that exogenous D-serine of dietary origin contributed at least in part to the D-serine levels found in mammalian tissues. The accumulation of radioactivity in the kidney, especially in the corticomedullary area, even at 24 hr after administration of 14C-D-serine suggested a possible link between acute necrosis of the renal proximal tubules and the administration of a large dose of D-serine [Am J Pathol 77: 269-282 (1974)].

Animals↗
PubMed1998

Successful treatment of radiation cystitis with hyperbaric oxygen therapy: resolution of bleeding event and changes of histopathological findings of the bladder mucosa.

To assess the effect of hyperbaric oxygen (HBO) therapy on radiation cystitis, clinical and histopathological characteristics were examined. Three women with radiation cystitis were treated with HBO therapy. Macrohaematuria was arrested in all patients. Cystoscopy demonstrated abnormal telangiectasia and inflammatory mucosa before treatment. After HBO therapy, the inflammatory mucosae were healed. However, abnormal vessels did not completely disappear. Histopathologically, the epithelium was atrophic and dilated lymph vessels and inflammatory cells were seen in the submucosa. These changes improved after treatment. HBO therapy is effective against radiation cystitis. With improvement of the clinical symptoms also the cystoscopic and histopathological findings changed favourably.

Aged↗
PubMed1998

Metastatic testicular germ cell tumour: the role of salvage surgery.

To assess the clinical characteristics of metastatic testicular germ cell tumour, response to chemotherapy and outcome of salvage surgery for residual mass were analyzed. Patients with complete response were carefully watched. Salvage surgery was performed in 14 patients after chemotherapy. Resected specimens showed 7 necrosis/fibrosis, 5 teratoma, 1 cancer, and 1 benign schwannoma. Only necrosis/fibrosis was found in cases without teratoma in the primary tumour. Existence of teratomatous elements in a primary tumour suggests that cancer or teratoma is present in the residual tumour. Furthermore, tumour reduction rate could not predict their presence in resected specimens.

Adolescent↗
PubMed1998

Growing mediastinal metastatic tumour in a patient with burned out testicular cancer.

A 27-year-old man was referred to us for resection of a post-chemotherapy growing mass in the mediastinum. He had been treated with 4 courses of combination chemotherapy for his testicular cancer. The primary lesion was burned out and the anterior mediastinal metastatic tumour contained immature teratoma. After normalization of tumour marker levels, the mediastinal mass was resected completely and the resected specimen showed teratoma with rhabdomyosarcoma. Two rare clinical conditions have been seen in this case.

Adult↗
PubMed1998

Prediction of functional recovery and prognosis in patients with acute myocardial infarction by 123I-BMIPP and 201Tl myocardial single photon emission computed tomography: a multicenter trial.

123I-BMIPP [15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid] was developed for metabolic imaging with SPECT. A multicenter collaborative study was conducted on a large patient series to determine whether 123I-BMIPP and 201Tl myocardial SPECT are of use in predicting the prognosis and ventricular function after acute myocardial infarction (AMI). Patients with uncomplicated first AMI underwent resting 123I-BMIPP and 201Tl myocardial SPECT in the subacute phase after the onset of AMI. Of these, 167 patients who had been followed up for an average of 22 months were retrospectively reviewed to predict serious cardiac events and recurrent ischemia. In addition, the association between changes in radionuclide parameters and recurrent ischemia was investigated in Subgroup A (58 patients) who had repeated SPECT in the chronic phase. Furthermore, prediction of the ejection fraction (EF) was investigated in Subgroup B (94 patients) and Subgroup C (76 patients) in whom left ventriculography was performed at the time of discharge and 90 days or more after the onset, respectively. The prognosis was generally favorable, with 4 cases of cardiac death (2%), 3 of heart failure (2%), 4 of nonfatal reMI (2%), and 25 of recurrent ischemia (15%). The results of Cox multivariate regression analysis revealed a high probability of serious cardiac events in patients who were elderly (p = 0.04), who had 90% or more residual stenosis of the infarct-related artery (p = 0.09), and who had a high BMIPP defect score (p = 0.17). There was a high probability of recurrent ischemia in elderly patients (p = 0.10) who had multi-vessel disease (p = 0.03), but no association was found with radionuclide parameters in the subacute phase. In Subgroup A, however, the probability of recurrent ischemia tended to be high in patients with a large mismatch scorebetween 123I-BMIPP and 201Tl in the subacute to chronic phase. An important observation was that the extent of BMIPP defect was more strongly correlated with EF at the time of discharge and 90 days or more after the onset than the extent of Tl defect (r = -0.60 vs. r = -0.47, and r = -0.53 vs. r = -0.43, respectively). In addition, multiple regression analysis showed that parameters related to the BMIPP defect were also better predictive factors of EF both at the time of discharge and 90 days or more after the onset. In conclusion, resting 123I-BMIPP and 201Tl myocardial SPECT performed in the subacute phase of AMI were shown to be useful in predicting prognosis and ventricular function for patient management.

Aged↗
PubMed1998

Evolution of myoglobin.

The distribution, physiological function, amino acid sequence and gene structure of myoglobin and myoglobin-like proteins from various taxa are summarized, and their evolution is discussed. Although it has long been thought that all haemoglobins and myoglobins have evolved from a common ancestral gene, the knowledge presently accumulated about the structures of these proteins suggests that there may be three distinct origins: a 'universal globin', a 'compact globin' and an 'IDO-like globin'.

Amino Acid Sequence↗
PubMed1998

Structural organization of rat CD1 typifies evolutionarily conserved CD1D class genes.

The non-major histocompatibility complex (MHC)-encoded CD1 family has recently emerged as a new antigen-presenting system that is distinct from either MHC class I or class II molecules. In the present study, we determined the genomic structure of the rat CD1 locus. It was extremely similar to mouse CD1 genes, especially to CD1D1. The 5' flanking region of the CD1 gene contained the binding motifs for two cytokine-inducible transcription factors, NF-IL2-A and NF-IL6. Some regulatory elements found in MHC class I genes (enhancer A, enhancer B, and the IFN response element) were absent. It is of interest that a tyrosine-based motif for endosomal localization found in the human CD1b cytoplasmic tail was encoded by a single short exon which was conserved in all CD1 molecules except for CD1a. Southern blot and direct sequencing analyses of inbred rat strains suggested very limited polymorphism in the 5' region where a hydrophobic ligand-binding groove is encoded; a single base substitution resulted in amino acid alteration of alanine (GCT) to valine (GTT) at codon 119. Comparison of the overall exon-intron organization of CD1 genes revealed that the length of the intron was also characteristic to each of the two classes of CD1 genes, classic CD1 and CD1D; such categorization has hitherto been made according to the sequence similarity of the coding region. This finding provides further support for the hypothesis that the two classes have different evolutionary histories. In contrast to the complete absence of the classic CD1 in rats and mice, the entire region of nonpolymorphic CD1D has been conserved through mammalian evolution. Similar functional properties of rodent CD1 and human CD1d are implied.

Amino Acid Sequence↗
PubMed1998

Antibody-dependent difference in biodistribution of monoclonal antibodies in animal models and humans.

The study was designed to clarify the difference in pharmacokinetics of monoclonal antibodies (mAb) in animal models and humans, and to elucidate the applicability of animal models. 99mTc-labeled murine mAb -- against carcinoembryonic antigen (designated BW431/26), and neural cell adhesion molecule (NE150) -- and one chimeric mouse/human mAb against nonspecific cross-reacting antigen (chNCA) were administered i.v. to normal mice and athymic mice (370 kBq, 400 ng) xenografted with human cancer cells expressing antigens, and into patients with tumor (925 MBq, 1 mg). The biodistribution of two of the three mAb (not 99mTc-BW431/26) differed clearly in mice and patients. 99mTc-NE150 showed specific uptake in xenografted tumor and otherwise a normal biodistribution; however, clinical examination showed increased uptake in the liver with rapid blood clearance (mean alpha half-life = 31.1 min) compared with 99mTc-BW431/26 (28.4 h). 99mTc-chNCA demonstrated increased blood clearance and renal excretion in both normal and athymic mice, with accumulation in tumors. Clinical examination showed rapid blood clearance (mean alpha half-life = 6.4 min) and increased uptake in the liver. High-performance liquid chromatographic analysis of 99mTc-chNCA revealed the immune complex in blood, suggesting uptake of the complex by the reticuloendothelial cells. The biodistribution of radiolabeled mAb in animal and human models was variable and specific for each of the three mAb. The results of animal studies with mAb should be evaluated carefully before being extrapolated to humans, on the basis of the nature of the mAb and interacting substances.

Animals↗
PubMed1998

Generation of polymorphic markers tightly linked to the thymus enlargement loci by phenotype-directed representational difference analysis.

To obtain genetic markers linked to a specific genetic locus, genomic subtraction with a DNA pool of backcross or F2 intercross animals with a specific genotype at the locus is known to be effective. To determine whether the pooling strategy is also effective for isolation of genetic markers linked to a quantitative phenotype that can potentially be controlled by multiple genetic loci, we tested the ability of representational difference analysis (RDA) to isolate genetic markers linked to the thymus enlargement observed in the BUF/Mna (BUF) rat. This is known to be controlled by single major and minor genes, Ten1 and Ten2, on Chromosomes (Chrs) 1 and 13, respectively, both of which have dose effects on the normal WKY/Ncj (WKY) allele. DNA from an inbred WKY rat was used as the tester, and the driver was prepared from a DNA pool of 12 (WKY x BUF)F1 x BUF backcross rats with high thymus ratios (thymus weight/body weight), expected to have dominance of the BUF allele in the responsible loci. By two RDA series with the restriction enzymes BglII and BamHI, respectively, 28 polymorphic markers were isolated, and 8 of them were shown to be linked to Ten1, and one to Ten2. One of the 8 markers linked to Ten1 demonstrated no recombination in 18 rats with high thymus ratios. RDA with a DNA pool based on a quantitative phenotype (phenotype-directed RDA) can thus be considered an efficient approach for direct isolation of polymorphic markers linked to a quantitative trait.

Animals↗
PubMed1998

Aspiration of intraspinal synovial cyst: recurrence after temporal improvement.

Intraspinal synovial cyst primarily occurs in the lumbar spine and may cause back pain and compression nerve disturbance. Percutaneous aspiration has been recommended as an alternative to surgery in three cases. We report on two patients who improved after aspiration of gelatinous material and steroid injection but whose cyst recurred within a short period of time. There are reportedly two types of synovial cyst: One contains serosanguineous fluid and the other gelatinous fluid. These two types are indistinguishable on computed tomography or magnetic resonance imaging. The results of all patients whose aspirated material was gelatinous were unsuccessful, including our cases. Thus, the outcome may depend on the pathology of the cyst.

Aged↗
PubMed1998

Hepatic stellate cells (vitamin A-storing cells) change their cytoskeleton structure by extracellular matrix components through a signal transduction system.

When cultured on a polystyrene surface or aminoalkylsilane-coated cover glasses, rat and human hepatic stellate cells exhibit a flattened, fibroblast-like shape with well-developed stress fibers. However, culturing the cells on type I collagen gel results in the elongation of long, multipolar cellular processes, whereas cells cultured on Matrigel maintain their round shapes. Dual fluorescence staining of microtubules and fibrillar actin indicated that the processes extend together with collagen fibers and contained microtubules as the core, whereas the periphery contained fibrillar actin. Immunofluorescence staining of vinculin showed that the focal adhesions were distributed mainly in lamellipodia when cultured on aminoalkylsilane-coated cover glasses, whereas in the cells cultured on type I collagen gel they were localized to the tips of the processes and along their bottom surface contacting collagen fibers. Wortmannin, as well as staurosporin and herbimycin A, inhibited the elongation process and induced the retraction of elongated processes. The wortmannin treatment also resulted in an alteration in focal adhesion distribution from the processes to cell bodies. These results indicate that the cell surface integrin binding to interstitial collagen fibers induces the elongation of processes through signaling events and the subsequent cytoskeleton assembly in hepatic stellate cells.

Androstadienes↗
PubMed1998

Enhancement of reactivity of anti-MUC1 core protein antibody and killing activity of anti-MUC1 cytotoxic T cells by deglycosylation of target tissues or cells.

MUC1 mucin core protein contains an important tumor-associated peptide antigen that can induce cytotoxic T cells (CTLs) in vivo, although this antigen is generally masked by mucin-type glycans. To reveal the precise expression pattern of MUC1 protein in normal and neoplastic gastric tissues, we performed immunohistochemical staining of periodic acid-treated tissue sections with an anti-MUC1 core protein monoclonal antibody (mAb), MUSE11. In non-cancerous tissues, the deep portion of fundic glands and the luminal surface were predominantly immunostained in normal and metaplastic glands, respectively. In cancerous tissues, the incidence of positivity for MUC1 protein varied from 67% to 88%, depending on histological type. This frequent expression of MUC1 protein in cancer tissues after periodic acid treatment suggested that deglycosylation may be of use for exposing the target antigen of anti-MUC1 CTLs. Accordingly, we then examined the effect of benzyl-alpha-GalNAc, an inhibitor of O-glycan biosynthesis, on the expression of MUC1 protein and sensitivity to an anti-MUC1 CTL line, designated TS, in gastric cancer JRST cells. After incubation with benzyl-alpha-GalNAc, the reactivity of mAb MUSE11 with JRST cells and their sensitivity of TS were clearly increased. These findings suggest that deglycosylation may offer an important strategy for enhancing anti-tumor immunity in patients with gastric cancer.

Acetylgalactosamine↗
PubMed1998

Detection of circulating anti-MUC1 mucin core protein antibodies in patients with colorectal cancer.

MUC1 mucin has a unique immunogenic peptide epitope in the extracellular domain, which has been shown to induce humoral and cellular immune response. In this study, we evaluated the pathophysiological significance of circulating anti-MUC1 mucin core protein IgG antibodies (anti-MUC1 antibodies) in colorectal cancer by Western blot analysis and 51Cr release assay. Anti-MUC1 antibodies were detected in 5 of 31 (16.1%) healthy subjects and in 27 of 56 (48.2%) patients with colorectal cancer. The presence of circulating anti-MUC1 antibodies was not significantly correlated with the level of circulating antigen MUSE11 or with other clinicopathological parameters tested. The incidence of positivity for anti-MUC1 antibodies in stage I and II (staged according to the General Rules for Clinical and Pathological Studies on Cancer of the Colon and Rectum of the Japanese Research Society for Cancer of the Colon and Rectum) cancers was 45.5% and 58.8%, respectively, suggesting that positivity for these antibodies may be of use as an adjunct for the diagnosis of colorectal cancer in the early stages in the absence of serious complications such as liver diseases. Because of the epitope similarity, anti-MUC1 antibodies in the serum may function in a manner similar to that of anti-MUC1 peptide monoclonal antibodies (mAbs). We therefore observed antibody-dependent cell mediated cytotoxicity with anti-MUC1 peptide mAb using MUC1 cDNA-transfected colon cancer CHC-Y1 cells as the target. The decreased sensitivity of MUC1 transfectants to effector cells was restored to a level equivalent to that in control cells. These data suggest that the detection of circulating anti-MUC1 antibodies may be a useful adjunct for the early diagnosis and immunological analysis of colorectal cancer.

Adult↗
PubMed1998

Goblet cell carcinoid of the appendix endoscopically diagnosed and examined with p53 immunostaining.

We report a case of a 62-year-old woman with goblet cell carcinoid of the appendix. She was admitted to our hospital in September 1994 after the discovery of liver tumors. After admission, a tumor in the right kidney and multiple tumors in the liver were found. She was diagnosed with renal cell cancer and metastasis to the liver and underwent excision of the kidney and enucleation of the largest liver tumor. Histological examination revealed that the liver tumor was a metastatic carcinoid tumor. As carcinoid tumors have frequently been found in the appendix, endoscopic examination was performed and a lesion was found in the appendix by colonoscopy. As predicted, the biopsy specimen was a carcinoid tumor, and she underwent an appendectomy. Histologically, the tumor was a goblet cell carcinoid. Goblet cell carcinoid is a rather rare neoplasm that has the histologic features of both carcinoids and adenocarcinoma. Forty-two cases of goblet cell carcinoid of the appendix have been reported thus far in Japan. However, few were diagnosed via endoscopic examination before surgical operation. We also carried out an immunohistochemical study with anti p53 antibody on the goblet cell carcinoid tumor of the appendix. Most tumor cells were strongly positive, while in three benign carcinoid tumors investigated simultaneously they were negative. These findings suggest that goblet cell carcinoid has an aggressive phenotype compared with benign carcinoid tumors.

Appendiceal Neoplasms↗