Assignment of fibroblast growth factor 18 (FGF18) to human chromosome 5q34 by use of radiation hybrid mapping and fluorescence in situ hybridization.
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Chromosome Banding↗
Biomedical subjects
T A Deisher
Publications and source records attributed to T A Deisher.
Statistical methods for analyzing repeated measures.
Repeated measurements arise frequently in biomedical research. In many situations, the scientific question of interest concerns finding differences in the measurements between groups. This question is frequently addressed by using analysis of variance-type methods that fail to incorporate information regarding the repeated sampling design of the experiment. In this paper, we provide an introduction to nonstatisticians of two approaches for analyzing such data. The procedures can be performed by using available software. These methods are illustrated on data from a preclinical study conducted by ZymoGenetics.
Angiotensin-Converting Enzyme Inhibitors↗
Synergistic effects of thrombopoietin and granulocyte colony-stimulating factor on neutrophil recovery in myelosuppressed mice.
Severe suppression of the hematopoietic system is a major factor in limiting chemotherapy dose escalation. To determine whether a combination of human recombinant granulocyte colony-stimulating factor (G-CSF) and thrombopoietin (TPO) would alter recovery of platelets, red blood cells (RBCs), or neutrophils after myeloablative therapy, myelosuppressed mice were treated with sc injections of TPO (90 micrograms/kg), G-CSF (250 micrograms/kg). TPO plus G-CSF or vehicle and complete blood counts were measured. Marrow and spleen cells were obtained at various times and assayed for erythroid, myeloid, and megakaryocytic progenitors. The prolonged neutropenia in vehicle controls (14 days) was significantly shortened in mice treated with G-CSF or TPO for 14 days. The combination of TPO plus G-CSF further reduced the duration of neutropenia. TPO and TPO plus G-CSF treatments also significantly shortened thrombocytopenia compared to vehicle. Recovery of RBCs was also enhanced in mice treated with either G-CSF or TPO, or the combination. Furthermore, treatment with G-CSF and/or TPO hastened myeloid, erythroid, and megakaryocyte progenitor recovery compared to vehicle controls. These results show that the combination of TPO plus G-CSF acts synergistically to accelerate neutrophil recovery in myelosuppressed mice and does not compromise the platelet or RBC response to TPO therapy.
Animals↗
Interleukin-4 induces endothelial vascular cell adhesion molecule-1 (VCAM-1) by an NF-kappa b-independent mechanism.
While all features of the inflammatory response induced by IL-1 are not observed following IL-4 stimulation, suboptimal concentrations both cytokines result in synergistic VCAM-1 expression in HUVEC. We have shown that, while IL-1 stimulated HUVEC express GM-CSF, tissue factor and VCAM-1, only VCAM-1 is detectable after exposure to IL-4. While kB was found essential for both basal and IL-1-mediated activity of VCAM-1, IL-4 induction was kB-independent. Inducible kB-binding proteins were identified in IL-1-, but not IL-4-stimulated nuclear extracts. Our results indicate that IL-4 exerts its transcriptional effects on the VCAM-1 gene through element(s) which do not require kB.
Cells, Cultured↗
Spontaneous reversibility of catecholamine-induced cardiotoxicity in rats.
In order to evaluate the chronic in vivo effects of excessive catecholamine levels, and the potential for spontaneous reversibility of these effects, we employed a chronic two-week infusion of epinephrine in rats. Epinephrine infusion resulted in myocyte hypertrophy, left ventricular fibrotic degenerative changes, diminished response to adrenergic stimuli, and enhanced left ventricular papillary contractile responses to calcium. Two weeks after cessation of the epinephrine infusion, left ventricular fibrotic degenerative changes were reduced, and responses to adrenergic stimuli were partially restored. However, myocyte hypertrophy and the enhanced responses to calcium persisted in these animals. This study indicates the potential for spontaneous reversal of some of epinephrine's toxic effects, and further implies that the loss in adrenergic sensitivity in epinephrine-treated animals may be a desensitization phenomenon, while the alterations in calcium response are less readily reversed.
Adenylyl Cyclases↗
The role of protein kinase C in the induction of VCAM-1 expression on human umbilical vein endothelial cells.
The role of protein kinase C (PKC) in interleukin-1 beta- (II-1 beta)-, tumor necrosis factor-alpha- (TNF-alpha)-, and lipopolysaccharide- (LPS)-induced vascular cell adhesion molecule-1 (VCAM-1) expression on human umbilical vein endothelial cells (HUVEC) was studied. PKC inhibition or downregulation diminished VCAM-1 mRNA accumulation and protein expression. Interleukin-1 beta, TNF-alpha, and LPS induce nuclear factor (NF)-kappa B-like binding activity, which precedes VCAM-1 transcription. PKC inhibition did not prevent NF-kappa B-like binding activity, indicating that this is PKC-independent, and NF-kappa B-like binding activity is insufficient for transcription of VCAM-1.
Base Sequence↗
A protein kinase C agonist, selective for the beta I isozyme, induces E-selectin and VCAM-1 expression on HUVEC but does not translocate PKC.
A protein kinase C (PKC) agonist selective for the beta I isozyme, 12-deoxyphorbol 13-phenylacetate 20-acetate (dPPA), induced NF-kappa B-like binding activity and surface expression of E-selectin and VCAM-1 in human umbilical vein endothelial cells (HUVEC), similar to the effects of tumor necrosis factor-alpha (TNF-alpha). Induction of E-selectin and VCAM-1 expression by dPPA was completely inhibited by the PKC inhibitors staurosporine and Ro31-7549. The PKC inhibitors also reduce TNF-alpha-induced VCAM-1 expression. However, neither dPPA nor TNF-alpha translocated PKC from the cytosolic to the plasma or nuclear membrane particulate fractions in HUVEC. These results indicate that activation of the beta I PKC isozyme is sufficient for expression of E-selectin and VCAM-1, and suggest that PKC may mediate the effects of TNF-alpha and dPPA without requiring the translocation normally associated with activation of PKC.
Alkaloids↗
Cytokine-induced adhesion molecule expression on human umbilical vein endothelial cells is not regulated by cyclic adenosine monophosphate accumulation.
We examined the effect of agents which augment intracellular levels of cyclic adenosine monophosphate on the expression of adhesion molecules on human umbilical vein endothelial cells. Surface protein expression of vascular cell adhesion molecule-1, endothelial leukocyte adhesion molecule-1, or intercellular adhesion molecule-1, which is induced by tumor necrosis factor, interleukin-1, and lipopolysaccharide, was not induced by pentoxyfilline, a phosphodiesterase inhibitor, nor by dibutyryl cyclic adenosine monophosphate. Furthermore, neither of these two cyclic adenosine monophosphate elevating agents nor HA 1004, an inhibitor of the cyclic adenosine monophosphate-dependent protein kinase, had any effect on tumor necrosis factor-alpha-induced surface expression of these adhesion molecules. Likewise, cyclic adenosine monophosphate elevating agents were without effect on leukocyte adherence to endothelium stimulated either with these agents alone or in combination with tumor necrosis factor-alpha. Additionally, activators of the stimulatory or inhibitory guanine nucleotide-dependent binding proteins did not affect TNF-alpha-induced surface expression of endothelial leukocyte adhesion molecule-1 or vascular cell adhesion molecule-1.
Cell Adhesion Molecules↗
Inhibitors of topoisomerase II prevent cytokine-induced expression of vascular cell adhesion molecule-1, while augmenting the expression of endothelial leukocyte adhesion molecule-1 on human umbilical vein endothelial cells.
Cytokine stimulation of human umbilical vein endothelial cells (HUVE) induces surface expression of the adhesion molecules vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin). We previously found that induction of adhesion molecule expression in HUVE is regulated, at least in part, by protein kinase C (PKC) activation, although this is not associated with the expected translocation of PKC from the cytosolic to the particulate fraction. We therefore investigated potential nuclear targets for PKC. Topoisomerase II is localized to the nuclear matrix and has been shown to be phosphorylated, both in vitro and in vivo, by PKC. In HUVE, the topoisomerase II selective inhibitors novobiocin, nalidixic acid, and etoposide prevented cytokine-induced VCAM-1 surface expression, but not E-selectin or ICAM-1 surface expression. Similarly, novobiocin and nalidixic acid reduced the accumulation of VCAM-1 mRNA in response to tumor necrosis factor-alpha treatment of HUVE. The inhibitory effect of the topoisomerase II inhibitors on VCAM-1 expression was not due to non-specific toxicity, as protein synthesis, measured by trichloroacetic acid precipitation of 35S-methionine labeled proteins, and transcription, determined by beta-actin mRNA levels, were not decreased. In contrast to the observed reduction of VCAM-1 mRNA accumulation and surface protein expression, inhibition of topoisomerase II activity enhanced E-selectin mRNA accumulation and surface protein expression in response to tumor necrosis factor-alpha stimulation of HUVE. This work demonstrates that topoisomerase II activity may differentially regulate the expression of adhesion molecules on HUVE.
Base Sequence↗
Protective effect of clentiazem against epinephrine-induced cardiac injury in rats.
We investigated the effects of clentiazem, a 1,5-benzothiazepine calcium antagonist, on epinephrine-induced cardiomyopathy in rats. With 2-week chronic epinephrine infusion, 16 of 30 rats died within 4 days, and severe ischemic lesions and fibrosis of the left ventricles were observed. In epinephrine-treated rats, left atrial and left ventricular papillary muscle contractile responses to isoproterenol were reduced, but responses to calcium were normal or enhanced compared to controls. Left ventricular alpha and beta adrenoceptor densities were also reduced compared to controls. Treatment with clentiazem prevented epinephrine-induced death (P < .05), and attenuated the ventricular ischemic lesions and fibrosis, in a dose-dependent manner. Left atrial and left ventricular papillary muscle contractile responses to isoproterenol were reduced compared to controls in groups treated with clentiazem alone, but combined with epinephrine, clentiazem restored left atrial responses and enhanced left ventricular papillary responses to isoproterenol. On the other hand clentiazem did not prevent epinephrine-induced down-regulation of alpha and beta adrenoceptors. Interestingly, clentiazem, infused alone, resulted in decreased adrenergic receptor densities in the left ventricle. Clentiazem also did not prevent the enhanced responses to calcium seen in the epinephrine-treated animals, although the high dose of clentiazem partially attenuated the maximal response to calcium compared to epinephrine-treated animals. In conclusion, clentiazem attenuated epinephrine-induced cardiac injury, possibly through its effect on the adrenergic pathway.
Animals↗
Platelet glycoprotein IIb-IIIa protein antagonists from snake venoms: evidence for a family of platelet-aggregation inhibitors.
The purification, complete amino acid sequence, and biological activity are described for several homologous snake venom proteins that are platelet glycoprotein (GP) IIb-IIIa antagonists and potent inhibitors of platelet aggregation. The primary structures of kistrin (from Agkistrodon rhodostoma), bitan (from Bitis arietans), three isoforms of trigramin (from Trimeresusus gramineus), and an isoform of echistatin (from Echis carinatus) were determined by automated sequence analysis and fast atom bombardment mass spectrometry analysis. Each of the protein in this family, which range from 47 to 83 residues, contains an Arg-Gly-Asp amino acid sequence found in protein ligands that binds to GPIIb-IIIa, a high (17 +/- 1%) cysteine content conserved in the primary sequence, and a homologous N-terminal region absent only in the echistatin isoforms. Each protein directly inhibits the interaction of purified platelet GPIIb-IIIa to immobilized fibrinogen about 100 times more effectively than does the pentapeptide Gly-Arg-Gly-Asp-Ser; IC50 values range from 1.1 to 3.0 nM. The IC50 value for the inhibition of platelet aggregation, using human platelet-rich plasma stimulated with ADP, ranges from 110 to 550 nM for the various proteins, about 1000-fold more potent than Gly-Arg-Gly-Asp-Ser. Kistrin binds reversibly to both resting and ADP-activated human platelets with high affinity (Kd = 10.8 nM and 1.7 nM, respectively) and to purified GPIIb-IIIa with a lower affinity (Kd = approximately 100 nM). Finally, kistrin injected at 1.0 mg/kg into rabbits reversibly inhibits platelet aggregation ex vivo over 30 min without induction of thrombocytopenia. We propose that these proteins are members of a general class of proteins found in the venom of pit vipers that inhibit platelet aggregation by antagonism of the GPIIb-IIIa-fibrinogen interaction and as such serve as potential antithrombotic agents.
Amino Acid Sequence↗
Role of cyclic AMP-dependent protein kinase in the diminished beta adrenergic responsiveness of vascular smooth muscle with increasing age.
Beta adrenergic receptor-mediated relaxation of blood vessels declines with age although the mechanism is unknown. We have utilized the mesenteric artery and aorta of young and older rats to investigate this problem. In vessels from 12-month-old rats there was a marked loss in relaxation mediated by beta adrenergic and adenosine receptors compared to younger rats whereas relaxation induced by muscarinic cholinergic receptors, [cyclic AMP (cAMP) independent], was not impaired. Maximal relaxation to forskolin and dibutyryl cAMP were intact in the vessels from older rats. Isoproterenol-stimulated cAMP accumulation and cAMP-dependent protein kinase activation were attenuated markedly in the vessels from the older rats. Maximal forskolin-stimulated cAMP accumulation and cAMP-dependent protein kinase activation were similar in older and young animals. There was an excellent correlation between cAMP-dependent protein kinase activity and relaxation and the relationship was similar in the two age groups. Continuous infusion of the beta adrenergic antagonist timolol for 1 week into older animals partially restored relaxation to beta adrenergic and adenosine receptor agonists in the aorta. These results suggest that the age-related loss of response to beta adrenergic receptor agonist-induced relaxation may be due in part to attenuated activation of cAMP dependent protein kinase and this change may be partially dependent on endogenous catecholamines.
Aging↗