Biomedical subjects

K Koike

Publications and source records attributed to K Koike.

At least 253 records · Page 14Linked to original sources

PubMed1997

Physical mapping of rice chromosomes 4 and 7 using YAC clones.

Physical maps of rice chromosomes 4 and 7 were constructed by landing yeast artificial chromosomes (YACs) along our high-density molecular linkage map. Using 114 DNA markers, 258 individual YACs were located on chromosome 4. Sixty-two out of 258 YACs carried two or more DNA marker positions and formed 16 contigs which covered a total length of 17.1 cM. The other YACs were arranged to 23 positions. On chromosome 7, 203 individual YACs were landed on 109 DNA markers. Sixty-four out of 203 YACs formed 15 contigs which covered a total length of 21.8 cM and 139 YACs were localized to 26 positions. Chromosomes 4 and 7 were covered with minimum tiling paths of 45 and 48 YACs, respectively. Taking the average size of YAC insert DNA to be 350 kb and the entire genome size to be 430 Mb, about 16-18 Mb of each chromosome or an estimated 50% of their total lengths have been covered with YACs. Physical maps of these 2 chromosomes should be of great help in identifying useful trait genes and unraveling genetic and biological characteristics in rice.

Animals↗

PubMed1997

Functional characterization of the 5'-flanking region of the gene encoding human 2-oxoglutarate dehydrogenase.

The 5'-flanking region of the gene (OGDH) encoding human 2-oxoglutarate dehydrogenase (OGDH) does not contain TATA or CAAT boxes, but contains an inverted GC box. To identify a functional OGDH promoter, systematic transient expression analysis of the 5'-flanking region (wild type, -3276/+212) of the OGDH was performed using serially nested deletions and linker-scanning mutations. The OGDH (wild type)-luciferase (LUC) reporter vector (pGV-E) construct and its deletion or linker-mutant constructs were transfected into BHK-21 cells and LUC activity was assessed. The OGDH-LUC construct expressed reproducibly >12-fold more LUC activity than did a control pGV-E vector. The promoter activity was up-regulated by treatment with 2-oxoglutarate and 2-oxoglutarate/glutamate. Deletions of sequences between nt -563 and -62 (M6 and M7) resulted in a 2-fold increase in LUC activity. Further deletion of the sequence between nt -61 and +212 (M8-M10) abolished LUC activity. High resolution mutagenesis within the -113 to -14 region indicated that the -53 to -44 and -33 to -24 sequences were required for positive regulation and the -93 to -84 sequence for negative regulation. We have identified a nuclear factor that binds to nt -63 to -24 including two cis-acting sites.

Animals↗

PubMed1997

Sialadenitis histologically resembling Sjogren syndrome in mice transgenic for hepatitis C virus envelope genes.

Hepatitis C virus (HCV), a major causative agent of non-A, non-B chronic hepatitis, is also suggested to be associated with extrahepatic manifestations such as mixed cryoglobulinemia and glomerulonephritis. Two independent lines of transgenic mice carrying the HCV envelope genes have been shown previously to express the HCV envelope proteins in organs, including the liver and salivary glands, which results in no pathological changes in the liver. Further analysis of these animals now has revealed that they develop an exocrinopathy involving the salivary and lachrymal glands. This pathology resembles Sjogren syndrome, which also is suggested to have a possible association with chronic hepatitis C. These observations suggest that HCV might be involved in the pathogenesis of sialadenitis in humans and that this transgenic mouse system would be a good animal model for the study of HCV infection.

Age Factors↗

PubMed1997

Iatrogenic paraplegia caused by surgicel used for hemostasis during a thoracotomy: report of a case.

A 46-year-old Japanese woman underwent a right lower lobectomy through a posterolateral incision made in the fifth intercostal space under general and epidural anesthesia on January 23, 1995. During the procedure, oxidized regenerated cellulose (Surgicel) was used to prevent postoperative rebleeding from the dorsal branch of the fifth intercostal artery. The following day it became evident that complete paraplegia had developed below the Th5 level, the cause of which was revealed by an emergency laminectomy, performed within 20 h after the thoracotomy, to be the Surgical treatment. By 50 days after the operation the patient had begun to show improvement, and was able to move her lower extremities against gravity. Her condition is continuing to improve.

Cellulose, Oxidized↗

PubMed1997

Purification and properties of mangano-superoxide dismutase from a strain of alkaliphilic Bacillus.

A mangano-superoxide dismutase (EC 1.15.1.1) was purified to homogeneity from a strain of alkaliphilic Bacillus for the first time. The purified protein, with an isoelectric point of pH 4.5, had a molecular mass of approximately 50 kDa and consisted of two identical subunits (25 kDa). The N-terminal amino acid sequence was Ala-Tyr-Lys-Leu-Pro-Glu-Leu-Pro-Tyr-Ala-Ala-Asn-Ala-Leu-Glu-Pro-His-Ile- Asp-Glu-Ala. The optimum pH and temperature for the reaction were 7.5 and 35 degrees C, respectively. The properties of the superoxide dismutase were compared with those of the enzyme from thermophilic Bacillus stearothermophilus.

Amino Acid Sequence↗

PubMed1997

Thermostable alkaline cellulase from an alkaliphilic isolate, Bacillus sp. KSM-S237.

Thermostable alkaline cellulase (endo-1,4-beta-glucanase, EC 3.2.1.4) activity was detected in the culture medium of a strictly alkaliphilic strain of Bacillus, designated KSM-S237. This novel enzyme was purified to homogeneity by a two-step column-chromatographic procedure with high yield. The N-terminal amino acid sequence of the purified enzyme was Glu-Gly-Asn-Thr-Arg-Glu-Asp-Asn-Phe-Lys-His-Leu-Leu-Gly-Asn-Asp-Asn-Val- Lys-Arg. The enzyme had a molecular mass of approximately 86 kDa and an isoelectric point of pH 3.8. The enzyme had a pH optimum of 8.6-9.0 and displayed maximum activity at 45 degrees C. The alkaline enzyme was stable up to 50 degrees C and more than 30% of the original activity was detectable after heating at 100 degrees C and at pH 9.0 for 10 min. The enzyme hydrolyzed carboxymethylcellulose, lichenan (beta-1,3;1,4-linkage), and p-nitrophenyl derivatives of cellotriose and cellotetraose. Crystalline forms of cellulose (Avicel and filter paper), H3PO4-swollen cellulose, NaOH-swollen cellulose, curdlan (beta-1,3-linkage), laminarin (beta-1,3;1,6-linkage), and xylan were barely hydrolyzed at all.

Amino Acid Sequence↗

PubMed1997

The pituitary folliculo-stellate cell line TtT/GF augments basal and TRH-induced prolactin secretion by GH3 cell.

Numerous functions have been ascribed to anterior pituitary folliculo-stellate (FS) cells. Recently, we established a pituitary FS-like cell line (TtT/GF) from an isologously transplantable pituitary thyrotropic tumor. Here we investigated the effect of FS cells on prolactin (PRL) secretion by using a co-culture system between TtT/GF cells and GH3 cells. We observed that co-culture with TtT/GF cells significantly increased basal PRL secretion without affecting the growth rate of GH3 cells. Further, addition of anti-cytokine-induced neutrophil chemoattractant (CINC) antibody partially reduced PRL secretion in co-culture of GH3 cells with 10% TtT/GF cells. Co-culture with 5% TtT/GF cells also markedly enhanced the PRL response to thyrotropin-releasing hormone (TRH) by GH3 cells, while addition of anti-CINC antibody had no effects on the enhanced PRL response to TRH. These results suggest that FS cells augment basal PRL secretion and enhance the secretory response of PRL to TRH by a paracrine mechanism.

Animals↗

PubMed1997

Steroidal glycosides from the underground parts of Hosta plantaginea var. japonica and their cytostatic activity on leukaemia HL-60 cells.

A new C22-steroid glycoside was isolated from the underground parts of Hosta plantaginea var. japonica, together with a known furostanol saponin and three known spirostanol saponins. The structure of the new steroid glycoside was characterized by spectroscopic analysis and acid-catalysed hydrolysis as 2 alpha, 3 beta, 16 beta-trihydroxy-5 alpha-pregn-20(21)-ene-carboxylic acid gamma-lactone 3-O-¿O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1--> 4)-beta-D-galactopyranoside¿. The isolated compounds were assayed for their cytostatic activity on leukaemia HL-60 cells. The spirostanol saponins showed cytostatic activity in a dose-dependent manner with the IC50 values ranging between 1 and 3 micrograms ml-1.

Antineoplastic Agents, Phytogenic↗

PubMed1997

Triterpenoid saponins from Mimusops elengi.

A novel minor triterpenoid saponin mimusin (3-O-[beta-D-glucopyranosyl- (1-->6)-beta-D-glucopyranosyl]-2 beta,3 beta,6 beta,23-tetrahydroxyolean- 12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L- rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside was isolated from the seeds of Mimusops elengi, in addition to two known triterpenoid saponins, Mi-saponin A and 16 alpha-hydroxy Mi-saponin A. The structure of the minor saponin was established by comparing its 13C NMR and LS-MS linked-scan, ESI-MS data with FAB-MS of the mimusopsin isolated earlier from the same source.

Carbohydrate Conformation↗

PubMed1997

Pituitary folliculo-stellate-like cell line produces a cytokine-induced neutrophil chemoattractant.

In previous studies, we reported that cytokine-induced neutrophil chemoattractant (CINC) was produced in the pituitary gland. Here we investigated the possibility of detection of CINC immunoreactivity in the pituitary folliculo-stellate (FS)-like cell line (TtT/GF). Intense immunoreactivity was observed by immunocytochemistry in the cytoplasm and cell processes of TtT/GF cells. CINC immunoreactivity was detected by an enzyme-linked immunosorbent assay in as little as 3 h after conditioning the medium with TtT/GF cells, and it increased significantly in a time-dependent manner during the first 24 h of the culture. This immunoreactivity could be induced by lipopolysaccharide and tumor necrosis factor-alpha in a time- and dose-dependent manner. We also observed the expression of CINC mRNA in TtT/GF cells and LPS increased CINC mRNA accumulation in TtT/GF cells. These findings indicate that CINC produced by FS cells may play a role as a paracrine factor of the anterior pituitary gland, and TtT/GF will provide a useful model system for studying the regulation of CINC secretion by FS cells.

Animals↗

PubMed1997

Noxious stimulation enhances release of cytokine-induced neutrophil chemoattractant from hypothalamic neurosecretory cells.

Cytokine-induced neutrophil chemoattractant (CINC), a member of IL-8 family in rat and a counter part of human growth-related oncogene product (GRO), was demonstrated to be synthesized in hypothalamic neurons and released in peripheral blood in response to noxious stimulation. CINC immunoreactive neurons were found mainly in supraoptic nucleus, while positive fibers were found in the median eminence and the posterior lobe of pituitary gland. Colchicine injection into the third ventricle demonstrated additional CINC positive neurons in both parvo- and magno-cellular parts of paraventricular nucleus, and an increase of positive fibers in the external layer of the median eminence. After formalin injection into the foot pad, CINC immunoreactivity substantially increased in the posterior lobe of the pituitary gland and in the external layers of the median eminence. In addition, a parallel increase of CINC level was noticed in the peripheral blood. It is suggested from the present results that, in response to a noxious stimulation, CINC is released from hypothalamic neurosecretory cells via both the anterior and posterior pituitary system. This cytokine mediated noxious response from CNS to peripheral tissue, would be a novel type of cross-talk between nervous and immune system.

Animals↗

PubMed1997

Identification of hepatitis B virus integration in hepatitis C virus-infected hepatocellular carcinoma tissues.

BACKGROUND/AIMS: The integration of HBV DNA is thought to be involved in the initial stage of hepatocarcinogenesis, and it has been reported that transactivating factors encoded by the X and preS2/S genes stimulate transcription of multiple viral and cellular genes. We assessed the possible contributions of hepatitis B virus integration to the occurrence of hepatocellular carcinoma in hepatitis C virus-infected as well as in hepatitis B virus-infected patients by identifying the integrated HBV DNA sequence, and the X and preS2/S regions were further investigated in HBV DNA-integrated cases. METHODS: Southern blot hybridization for detecting HBV DNA in tumor tissues from 28 hepatocellular carcinoma patients was carried out with full-length HBV DNA, and then with X and preS2/S regions as probes. We also carried out reverse transcription-polymerase chain reaction for detecting HCV RNA to confirm hepatitis C virus-infection in liver tissues. RESULTS: Clonally integrated HBV DNA sequences were demonstrated in 16 of 28 patients (57.1%), including five HBsAg seropositive and 11 HBsAg seronegative patients. Of these 11 HBsAg seronegative patients, 10 were also positive for anti-HCV in their sera, and all nine examined cases had HCV RNA in liver. Furthermore, the X region was identified in 14 of 16 HBV DNA integrated cases (87.5%), and the preS2/S region in 6/16 (37.5%). CONCLUSIONS: The present Southern blot analysis demonstrates that clonally integrated HBV DNA sequences were identified even in hepatitis C virus-infected hepatocellular carcinoma patients at a high rate (10/18, 55.6%), and suggests that integrated hepatitis B virus, whose major component is the X gene, may play an important role in hepatocarcinogenesis in hepatitis B virus-integrated cases with and without hepatitis C virus infection.

Adult↗

PubMed1997

Characteristics of [3H]CGP12177 binding sites at beta 2- and beta 3-adrenoceptors in the guinea pig taenia caecum.

1. Experiments were carried out to characterize the [3H]CGP12177 binding sites in the microsomal fraction from the guinea pig taenia caecum. 2. The Scatchard plot in the absence of butoxamine (10(-4) M) or bupranolol (10(-4) M) was concave, suggesting two affinity sites: high and low affinity binding sites. 3. The Scatchard plot in the presence of butoxamine gave a straight line, indicating only the low affinity site. 4. The Scatchard plot in the presence of bupranolol was undetectable. 5. These results suggest that the high affinity binding sites for [3H]CGP12177 correspond to beta 2-adrenoceptors in the microsomal fraction from the guinea pig taenia caecum, whereas the low affinity binding sites represent beta 3-adrenoceptors.

Adrenergic beta-Agonists↗

PubMed1997

Gianotti-Crosti syndrome associated with cytomegalovirus antigenemia after bone marrow transplantation.

Gianotti-Crosti syndrome (GCS) is characterized by a distinctive self-limiting acral papular or papulovesicular eruption associated with an underlying viral illness. It has not been previously reported in patients post-bone marrow transplantation. We report a 6-year-old Japanese boy who underwent allogeneic bone marrow transplantation from an unrelated donor for acute lymphoblastic leukemia (ALL) in second remission. He had clinical and histopathologic findings characteristic of GCS and evidence of subclinical infection with cytomegalovirus (CMV) detected by CMV antigenemia assay. It is likely that CMV is the causative agent for the GCS in this case.

Acrodermatitis↗

PubMed1997

Megakaryocytes derived from CD34-positive cord blood cells produce interleukin-8.

In a serum-free liquid culture, thrombopoietin (TPO) selectively stimulated the growth of megakaryocytic cells from CD34-positive cord blood cells. Using these cultured cells, we investigated cytokine production by human megakaryocytes. Day 10 megakaryocytes (2 x 10(5)) secreted > 1000 pg/ml of interleukin (IL)-8, in contrast to small amounts of IL-1beta and IL-6. A time-course study showed that the IL-8 production of megakaryocytes occurred at the late phase of the culture period. The megakaryocyte-conditioned medium had the chemotactic potential of polymorphonuclear leucocytes, which was abrogated by the addition of anti-IL-8 antibody, suggesting the secretion of biologically active IL-8. The combination of TPO and IL-1alpha was required for a significant augmentation of the IL-8 secretion. Direct evidence for IL-8 synthesis in megakaryocytes was provided by reverse transcription-polymerase chain reaction on purified CD41b+ cells and by the detection of intracellular IL-8 in CD41b+ cells. These results suggest that TPO stimulates not only the proliferation and differentiation of the progenitors capable of megakaryocytic lineage expression but also IL-8 release by the megakaryocytic cells with the aid of IL-1.

Cells, Cultured↗

PubMed1997

Hepatitis C virus core protein induces hepatic steatosis in transgenic mice.

Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide, which finally leads to development of hepatocellular carcinoma. Chronic hepatitis C is characterized by several histological features in the liver which discriminate it from other forms of hepatitis: bile duct damage, lymphoid follicles and steatosis (fatty change). Little is known, however, about the role of HCV or its viral proteins in the pathogenesis of hepatitis. Recently, the core protein of HCV has been suggested to have a transcriptional regulatory function, and thereby to be involved in inducing phenotypic changes in hepatocytes. To clarify whether or not the HCV core protein has an effect on pathological phenotypes in the liver, two independent transgenic mouse lines carrying the HCV core gene were established. These mice developed progressive hepatic steatosis, indicating that the HCV core protein plays a direct role in the development of hepatic steatosis, which characterizes hepatitis C. This transgenic mouse system would be a good animal model for the study of pathogenesis in human HCV infection.

Animals↗

PubMed1997

Clinicopathologic study of nasal T/NK-cell lymphoma among the Japanese.

A high prevalence of nasal lymphoma expressing a T- or natural killer (NK)-cell phenotype (NTCL) with frequent association of Epstein-Barr virus (EBV) has been indicated in Asians. To characterize NTCL among the Japanese, the clinicopathologic features of 32 cases were evaluated and the cases were also analyzed for EBV-RNA using an ISH method. Morphologically, 31 cases were identified by atypical pleomorphic lymphoid infiltrates with polymorphous, angicentric, and necrotic features. Their lymphoma cells ranged in size from small to large and were mixed in varying proportion from case to case. The other one case showed a monomorphic 'blastic' appearance. EBV-encoded small RNA (EBER) was detected in the neoplastic cells of 27 of the 32 cases examined. In the five EBV-negative cases, one was the 'blastic' type. Clonal T-cell receptor gene rearrangement was detected in none of seven cases examined. The patients had a median follow-up of 9 months (range, 1 month to 14 years and 11 months). The Kaplan-Meier estimate of overall survival was 49% at 5 years, correlating with clinical stage. These data support the concept that most cases of NTCL are identified as tumors with T/NK-cell characteristics and EBV association, distinctly different from other peripheral T-cell lymphomas. Furthermore, the one case of an EBV-negative 'blastic' variant appears not to fit well into the pleomorphic category but more closely resembles the pathologic features of extranasal angiocentric lymphoma with lymphoblastoid appearance. This study also showed no clear difference in clinical aspects other than the original site or in prognosis, between NTCL and extranasal angiocentric lymphomas despite the higher incidence of EBV association and the tendency for that peculiar anatomical site to be restricted to the former group.

Adolescent↗

PubMed1997

GRO-alpha in human serum: differences related to age and sex.

PROBLEM: Human GRO-alpha (GRO-alpha) is a new member of the chemokine family that is supposed to play an important role in inflammatory and immune reactions. We established a sandwich enzyme-linked immunoassay (ELISA) system with polyclonal antibodies against human GRO-alpha and investigated the serum level of healthy donors to establish normal ranges for this chemokine in adults. METHODS: GRO-alpha concentrations were measured cross-sectionally in the sera of 240 healthy adults. The variability of serum GRO-alpha levels was also measured in normal volunteers, samples from whom were obtained by sequential venipunctures or by a small plastic cannula with a heparin-saline lock, to determine short-term variability. RESULTS: Whereas there was no difference between the concentration of human GRO-alpha from men (logarithmic mean, 77.6 pg/ml, n = 120) and that from women with normal menstrual cycles (log mean, 71.6 pg/ml, n = 73), the concentration from postmenopausal women (log mean 45.0 pg/ml, n = 31) was lower than that from women with normal menstrual cycles (log mean 71.6 pg/ml, n = 73). However, we could not detect any significant difference between healthy donors' serum levels and those of donors with acute inflammation. Fewer variations were recognized in the case of the sequential venipunctures method than in that of the heparin-saline lock method. CONCLUSION: We found that the GRO-alpha concentration of postmenopausal women was significantly lower than that of women with normal menstrual cycles. These results suggest the GRO-alpha serum levels of normal healthy women may have some correlation with sex hormones.

Acute Disease↗