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Biomedical subjects

A Fuse

Publications and source records attributed to A Fuse.

At least 37 records · Page 2Linked to original sources
PubMed1997

Induction of polyploidization in the human erythroleukemia cell line (HEL) by protein kinase inhibitor (K252a) and the phorbol-ester TPA.

Endomitosis (polyploidization) is a distinctive feature of megakaryocyte differentiation. We examined this mechanism in an erythromegakaryocytic cell line, HEL, using a protein kinase inhibitor K252a or a phorbol-ester TPA. HEL cells treated with K252a showed a marked increase in the proportion of CD41 positive cells and polyploid cells as well as in cellular size and nuclear size. TPA showed similar results but induced multi-nucleation instead of enlargement of nuclear size. K252a added at the G1/S boundary phase did not inhibit the first and second round DNA synthesis, but inhibited cell division. K252a did not inhibit the expression of genes involved in mitosis such as cyclin B, cdc25B and cdc2, in the first round S phase. However, the cyclin B associated Cdc2 kinase activity needed for mitosis during the G2/M phase was reduced by K252a. TPA delayed DNA synthesis and expression of these genes, and suppressed Cdc2 kinase activity in the second round G2/M phase. These results suggest that the polyploidization induced by K252a results from inhibiting mitosis possibly caused by suppression of Cdc2 kinase activity. TPA may induce the multi-nucleation through a different mechanism.

Antigens, CD34↗
PubMed1997

In vitro and in vivo evaluation of BO-2727 against imipenem- and/or meropenem-resistant Pseudomonas aeruginosa.

The in vitro and in vivo activity of BO-2727, a carbapenem antibiotic, against resistant clinical isolates of Pseudomonas aeruginosa was studied. The geometric mean MICs against three groups of clinical isolates resistant to imipenem, meropenem and both carbapenems were 4.28, 4.08 and 5.44 micrograms/ml, respectively. BO-2727 also inhibited multiply antibiotic resistant isolates and laboratory mutants including a nalB-type mutant, which showed resistance to antibiotics such as imipenem, meropenem, ceftazidime, and/or ciprofloxacin, at less than 1.56 micrograms/ml. Overall, BO-2727 was 4-fold more active than biapenem, meropenem, panipenem and imipenem with an MIC90 of less than 6.25 micrograms/ml. The presence of basic amino acids in minimal medium less affected the antipseudomonal activity to a minimal extent, suggesting that BO-2727 has diverse penetration routes through the outer membrane other than OprD channel, which facilitates the diffusion of basic amino acids and carbapenems. The in vitro activity of BO-2727 reflected well in its therapeutic efficacy in experimental systemic infection in mice. These results suggest a possibility for the development of antipseudomonal carbapenems having activity against imipenem- and/or meropenem-resistant P. aeruginosa as well as a broad spectrum encompassing Gram-positive and -negative bacteria.

Animals↗
PubMed1996

Expression patterns of Raf-1 suggest multiple roles in tooth development.

Raf-1, the product of proto-oncogene c-raf-1, has key roles in the signal transduction pathways within the cell. The molecular mechanisms of tooth development in the mouse embryo are not known in detail. We examined the expression of Raf-1 during subsequent tooth development by immunohistochemical analysis. In mouse embryos at days 12.5 post-coitum (p.c.), Raf-1 was expressed in the dental invaginating epithelium. At p.c. 13.5 (bud stage), Raf-1 was also expressed in the epithelial cells of the enamel organ, but not in the mesenchyme of the dental papilla. We added anti-proliferating cell nuclear antigen (PCNA) antibody as a marker for proliferating cells at early stages of tooth development. At p.c. 12.5 and p.c. 13.5, the staining patterns were very similar to that for Raf-1. At p.c. 15.5 (cap stage), Raf-1 could not be detected. At p.c. 17.5 (bell stage), Raf-1 was expressed in both the odontoblastic and subodontoblastic cells of the dental papilla. However, Raf-1 was not found in the epithelial cells of the enamel organ. We also added anti-type I collagen antibody as a marker for odontoblasts differentiation. The staining pattern for type I collagen antibody as a marker for odontoblasts differentiation. The staining pattern for type I collagen in odontoblasts was almost the same as for Raf-1. The results suggest that Raf-1 may play some roles in both cell proliferation and differentiation at different stages of tooth germ development.

Animals↗
PubMed1996

A novel human leukaemic cell line, CTS, has a t(6;11) chromosomal translocation and characteristics of pluripotent stem cells.

A novel human leukaemic cell line, designated CTS, was established from the peripheral blood of a 13-year-old girl suffering from acute myeloblastic leukaemia (AML) in relapse. CTS cells expressed CD7, CD13, CD33, CD34 and HLA-DR antigens, and showed ultrastructural myeloperoxidase activity. In addition, CTS cells showed DNA rearrangements of the immunoglobulin heavy chain gene and the light kappa chain gene, and deletions of the T-cell receptor delta 1 gene. Cytogenetic analysis revealed a human female diploid karyotype with a t(6;11)(q27;q23) chromosomal translocation. Molecular studies demonstrated a DNA rearrangement of the MLL gene, the expression of a truncated 11.0 kb MLL mRNA and the detection of the MLL/AF-6 fusion transcript in CTS cells. To our knowledge, this cell line is the first report of a human leukaemic cell line with a t(6;11) chromosomal translocation. CTS cells showed no significant proliferative response to the cytokines, IL-2, IL-3, IL-6, IL-11, GM-CSF, G-CSF, EPO, SCF, but were induced to differentiate to the T-cell, B-cell, erythroid or megakaryocytic lineage in the presence of particular cytokines. This CTS cell line may provide a useful tool in the study of the oncogenesis of mixed lineage leukaemia with 11q23 abnormalities and for the analysis of growth and differentiation of pluripotent stem cells.

Adolescent↗
PubMed1996

The effect of methylprednisolone on myocardial beta-adrenergic receptors and cardiovascular function in shock patients.

The effect of methylprednisolone on the myocardial beta-adrenergic receptors after long term ( > 72 h) catecholamine infusion was studied. In 56 patients with pulmonary arterial catheter, 10 mg/kg of methylprednisolone was given as an intravenous bolus. Significant increases could be seen in cardiac output and blood pressure in patients who were simultaneously treated with vasopressors like dopamine and/or dobutamine. In patients who were on dopamine infusion higher than 10 micrograms/kg/min methylprednisolone there was an increase in the systemic vascular resistance. Patients who were not on vasopressors but received methylprednisolone, had no similar changes in hemodynamic parameters. In an in vitro analysis of tissue from the myocardium in 12/56 patients who succumbed and in four additional patients who expired after multiple trauma, a beta-adrenergic receptor assay was performed. It was found that the long term infusion of catecholamines decreased the receptor number and the methylprednisolone abolished or caused the decrease to be less pronounced. In this study we could not control the selection of the patients; a randomized study needs to be conducted in the future.

Adult↗
PubMed1995

Enhanced phosphorylation of nuclear 21-kDa and 34-kDa proteins in hepatoma cell death induced by tumor-necrosis factor-alpha.

The role of nuclear protein phosphorylation in intracellular signal transduction of tumor-necrosis factor-alpha (TNF-alpha) in the human hepatoma cell line PLC(PRF/5) was investigated. TNF-alpha, which displays cytolytic activity against PLC hepatoma cells, elevated the in vitro phosphorylation of two nuclear proteins (21 kDa and 34 kDa) 16 h after treatment. The cytotoxicity and enhanced nuclear protein phosphorylation by TNF-alpha treatment decreased in the presence of dexamethasone. Both the 21-kDa and 34-kDa proteins were extracted with 2.2 M NaCl from nuclear pellets and phosphorylated in kinase reaction mixtures containing a high concentration of salt. By phosphoamino acid analysis, the specificity of the nuclear kinase was found to be directed toward serine residues. The protein kinase inhibitors H7, staurosporine and herbimycin A, inhibited the phosphorylation of the 21-kDa and 34-kDa proteins in vitro, but calphostin C and heparin did not. The treatment of cells with 4 beta-phorbol 12-myristate 13-acetate or okadaic acid did not affect the in vitro phosphorylation of the two nuclear proteins. An anti-Fas antibody increased the phosphorylation of the 21-kDa and 34-kDa proteins in PLC cells. DNA fragmentation was observed in PLC cells treated with TNF-alpha and anti-Fas antibody after 24 h treatment. These data suggest an involvement of nuclear protein kinase in signal-transduction pathways of apoptotic cell damage triggered by TNF-alpha in PLC hepatoma cells.

Apoptosis↗
PubMed1995

Corticosteroid effect on early beta-adrenergic down-regulation during circulatory shock: hemodynamic study and beta-adrenergic receptor assay.

OBJECTIVES: The steroid effect on critically ill patients remains controversial. The aim of this study is to characterize the effect of methylprednisolone on the heart in a beta-adrenergically down-regulated condition. DESIGN: A prospective hemodynamic study and retrospective receptor assay. SETTING: Multidisciplinary ICU in a university hospital. SUBJECTS: 42 patients who required pulmonary arterial catheters and an additional 4 corpses who were available for study within 3 h of their deaths. INTERVENTION: Intravenous methylprednisolone (10 mg/kg). MEASUREMENTS AND RESULTS: We pursued a hemodynamic study following a glucocorticoid administration. In patients who had undergone a long term (> 72 h) catecholamine treatment, the cardiac index increased. In patients who had undergone a short term (1-72 h) catecholamine treatment and in patients with no record of catecholamine administration, the cardiac index showed no remarkable change. Among the corpses, who died soon after their arrival, and the patients, who later died in the ward and were available for further study, we measured beta-adrenergic receptor density in the left ventricular myocardium. It was found that receptor density was decreased after long term catecholamine treatment. Methylprednisolone, on the other hand increased the receptor density. CONCLUSION: Methylprednisolone improved the cardiac index, intriguingly, in patients with long term catecholamine treatment in circulatory shock. Myocardial beta-adrenergic receptor also increased in number after the administration of methylprednisolone. However, the hemodynamic improvement caused by methylprednisolone was not observed in patients without beta-adrenergic down-regulation.

Adrenergic beta-Antagonists↗
PubMed1995

Mechanism of enhanced antipseudomonal activity of BO-2727, a new injectable 1-beta-methyl carbapenem.

The mechanism of the enhanced activity of BO-2727 against imipenem-resistant Pseudomonas aeruginosa was studied by using a set of four isogenic strains derived from beta-lactamase-deficient P. aeruginosa PAO4089 (blaJ blaP). Complementation of the blaJ and blaP mutations conferred greater resistance to biapenem, panipenem, and imipenem than to BO-2727 and meropenem, most notably in the outer membrane protein D2-deficient strain. The higher levels of resistance to biapenem, panipenem, and imipenem can be explained by the slow but significant hydrolysis by beta-lactamase, whereas the reduced levels of resistance to BO-2727 and meropenem would be attributable to their stability in the presence of high levels of beta-lactamase and the fact that they cause only low induction of beta-lactamase. It is also noted that the activity of BO-2727 against the beta-lactamase-deficient strain was less affected by the loss of the D2 porin than was that of meropenem, indicating that BO-2727 in comparison with meropenem can overcome an intrinsic resistance caused by the loss of D2. Moreover, comparative in vitro resistance studies have shown that BO-2727 and meropenem selected fewer resistant cells than other carbapenems. In conclusion, BO-2727 exhibited improved activity against imipenem-resistant P. aeruginosa, probably because of its ability to overcome loss of the D2 porin and beta-lactamase hydrolysis.

Anti-Bacterial Agents↗
PubMed1995

Expression of multidrug resistant gene (mdr-1/P-glycoprotein) in a megakaryoblastic cell line, CMK, and its enhancement during megakaryocytic differentiation.

Multidrug resistance is a severe clinical problem in the chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often resistant to many anti-cancer chemotherapeutic drugs. Here we report the expression of the mdr-1/P-glycoprotein in a cell line, CMK, established from a patient with AMKL. Expression of mdr-1 mRNA in CMK11-5 cells, a well differentiated subline, was higher than in CMK6 cells, a poorly differentiated subline. The level of P-glycoprotein was also higher in CMK11-5 cells. The cytokines interferon-gamma (IFN-gamma), GM-CSF and IL-3, which were shown to induce megakaryocytic differentiation of CMK cells, enhanced the expression of the mdr-1 mRNA and levels of P-glycoprotein. These results imply that differentiated megakaryocytic cells may have higher levels of the P-glycoprotein expression, suggesting a possible normal physiological function of P-glycoprotein in mature megakaryocytes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Changes in muscle and liver lactate concentrations after endotoxin infusion in rats.

The interstitial lactate concentration in rat skeletal muscle and liver was measured using a microdialysis method during the early stage of endotoxemia and during lactic acid infusion. The lactate concentration in the muscle and liver interstitium never exceeded the blood lactate concentration throughout the 180 min period after endotoxin administration. The present findings also showed that the muscle and liver interstitial lactate concentration gradually increased in endotoxin-infused animals compared to that in lactic-acid infused animals, although the blood lactate concentration in lactic acid-infused animals was the same as that in endotoxin-infused animals. These findings suggest that the skeletal muscle and liver may consume lactate in an endotoxemic condition. However, the capacity of lactate consumption in the skeletal muscle might gradually decrease after endotoxin administration, although that in liver might be well preserved.

Animals↗
PubMed1993

[Continuous intracarotid infusion of mannitol in severe head injury].

The clinical significance of continuous intracarotid infusion of a small dose of mannitol (ICI of mannitol) was discussed. Eighteen patients suffering from severe head injury with Glasgow coma scale (GCS) less than 6 were treated by ICI of mannitol for the improvement of raised intracranial pressure (ICP). In all of these 18 cases, conventional venous administration of mannitol could not be carried out, because of the unstable vital signs due to hypovolemic shock such as multiple trauma or disturbance of serum sodium and potassium levels. This method requires that a 20% mannitol solution be directly and continuously administered to the bilateral common carotid artery. The ICP 6 hours after the beginning of ICI of mannitol was significantly lower than the ICP just before the treatment. The total amount of excretion of the sodium and potassium through the urine every hour decreased significantly after this method was used. It was also noticed that this method was very suitable for stabilizing the vital signs in cases which had unstable vital signs such as hypovolemic shock. These findings suggested that ICI of mannitol has an advantage over the conventional venous administration of mannitol in cases which had to have correction of serum electrolyte or which had unstable vital signs.

Adolescent↗
PubMed1992

Human papillomavirus type 13 and pygmy chimpanzee papillomavirus type 1: comparison of the genome organizations.

Human papillomavirus type 13(HPV-13) is associated with oral focal epithelial hyperplasia (FEH) in humans. A recent epidemic of a FEH-like disease in a pygmy chimpanzee (Pan paniscus) colony allowed us to clone a novel papillomavirus genome. To assess the homology between HPV-13 and the pygmy chimpanzee papillomavirus type 1 (PCPV-1), the complete nucleotide sequences of both FEH-related viruses were determined. In both viruses, all eight major open reading frames were located on one strand and the genomic organization was similar to that of other mucosal papillomaviruses. The genomes of PCPV-1 and HPV-13 showed extensive overall sequence homology (85%). They could be classified, using phylogenetic analysis, together with HPV types 6, 11, 43, and 44 in a group associated with benign orogenital lesions. These data indicate that two phylogenetically related papillomaviruses can elicit similar pathology in different primate host species, reflecting viral genomic similarities.

Animals↗
PubMed1992

The induction of IL-6 and gelatinase B by IL-1 in mouse cell lines transformed with bovine papillomavirus: decreased production in tumorigenic cells.

Six cell lines, that were cloned from murine C127 cells infected by bovine papillomavirus type 1 (BPV1), were found to differ in the degree of transformation in vitro and of tumorigenicity in vivo. In these cell lines the degree of tumorigenicity was inversely correlated with IL-6 induction by IL-1 beta. Whereas the parental C127 cell line produced 15-30 U/ml of IL-6 spontaneously, none of the transformed cell lines produced significant levels of IL-6 constitutively. On induction by human IL-1 beta the parental C127 cell line produced up to 300 U/ml of IL-6, whereas the fully transformed ID14 cell line failed to produce any. The less transformed cell lines produced lower yields of IL-1 beta-induced IL-6, dependent on their degrees of transformation and tumorigenicity. Gelatinase B (96 kDa), a matrix metalloproteinase inducible by IL-1 beta, was dose-dependently regulated in the parental C127 cell line and in the weakly transformed cell line Tlc. These data suggest that transformation processes by BPV1 generally impair IL-1-regulated gene transcription. This impairment seems not to be located at the IL-1 beta receptor level, since in all the cell lines studied the numbers and affinities of the IL-1 beta binding sites were found to be comparable. This impairment seems not to be mediated by transformation-induced inactivation of the protein kinase C pathway since phorbol 12-myristate 13-acetate (PMA) induced IL-6 production equally well in all C127 cell-derived clones. It is suggested that BPV1 transformation can change the expression of host genes that might play a functional role in tumor immune surveillance and tumorigenicity in vivo.

Animals↗
PubMed1992

[Amnesic effect of oral midazolam as premedication in children].

We evaluated the sedative and amnesic effects of oral midazolam as premedication in children. Sixteen children, aged 4-12 yr, undergoing elective minor surgery were divided into 2 groups. One group received midazolam 0.5 mg.kg-1 with atropine 0.03 mg.kg-1 orally. The other control group received only atropine 0.03 mg.kg-1. There was no significant difference in the sedative scale at induction between the 2 groups. Doll-recall was used to assess the amnesic effects. In the midazolam group, 75% of the children forgot dolls they had seen on entering the operating room. Midazolam produced significant anterograde amnesia but no retrograde amnesia. This result suggests that children who received midazolam as premedication forget unpleasant memories at induction and their postoperative emotional responses are least influenced by their memories. We conclude that oral midazolam 0.5 mg.kg-1 is an effective preanesthetic medication in children.

Administration, Oral↗
PubMed1991

Human papillomavirus type 6 and 11 E4 gene products in condyloma acuminata.

The human papillomavirus type 6 (HPV-6) E4 gene was expressed in Escherichia coli as a fusion protein with E. coli beta-galactosidase (E4-beta-Gal), and rabbit antibody against the E4-beta-Gal was prepared. By Western blotting with this antibody, we detected E4 gene products in six out of 18 condyloma acuminata specimens. In four specimens (C-1, C-13, C-14 and C-19), the E4 protein was found as a 10K/11K doublet, but in other specimens (C-8 and C-23), only the 11K protein was detected. By Southern blot analysis, it was found that C-13 harboured HPV-6 DNA but that C-1 and C-8 harboured HPV-11 DNA, indicating that the E4 proteins of HPV-6 and -11 have cross-reactive antigenicity. After incubation at 37 degrees C of the C-23 tissue specimen, the 10K protein was clearly detected. These results suggest that the 10K protein may be derived from the 11K protein by a modification such as proteolytic cleavage before and/or after specimens were taken.

Base Sequence↗
PubMed1991

Interleukin 6, a possible autocrine growth and differentiation factor for the human megakaryocytic cell line, CMK.

CMK is a human cell line derived from a megakaryoblastic leukaemia. It has characteristics of the megakaryocytic lineage, such as the presence of platelet peroxidase, membrane glycoproteins (GP)Ib and GPIIb/IIIa, alpha-granules, and demarcation membranes. The cell line proliferates autonomously in serum-containing medium. Here we report that the cell line expresses the gene for IL-6 and releases small quantities of the cytokine into the medium. Addition of exogenous IL-6 to cultures seeded into medium was found to promote growth of the cells. Conversely, addition of a neutralizing anti-IL-6 antibody inhibited cell growth. These data support the notion that autocrine IL-6 is one of the factors accounting for autonomous growth of the cell line.

Blotting, Northern↗
PubMed1991

A papillomavirus related to HPV type 13 in oral focal epithelial hyperplasia in the pygmy chimpanzee.

An epizootic of focal epithelial hyperplasia (FEH) or Morbus Heck in a pygmy chimpanzee (Pan paniscus) colony is described. Papovavirus-like particles were observed in the nuclei of epithelial cells. Analysis of the DNA of the lesions revealed an episomal papillomavirus-specific band with a molecular size of approximately 8,000 bp. In situ hybridization under high stringency conditions showed cross-hybridization between the chimpanzee papillomavirus DNA and human papillomavirus (HPV) type 13. The latter virus is uniquely associated with oral disease in man. This is the first demonstration of the association of a HPV 13-related pygmy chimpanzee papillomavirus (PCPV) and oral epithelial hyperplasia in a nonhuman primate.

Animal Diseases↗