Helenalin, an anti-inflammatory sesquiterpene lactone from Arnica, selectively inhibits transcription factor NF-kappaB

The cyclin-dependent kinase, proliferating cell nuclear antigen, and stress-activated protein kinase/c-jun NH2 terminal kinase inhibitor p21WAF1/CIP1 can induce G1 arrest, and its expression coincides with the cessation of replication in many systems. We examined expression of p21 during the early stages of carbon tetrachloride intoxication in the mouse liver and observed a dramatic increase in p21 RNA levels between 4 and 8 h after administration. p21 expression, visualized by in situ hybridization, is induced in pericentral hepatocytes before carbon tetrachloride-induced necrosis. Examination of c-fos and c-myc expression patterns confirm that these immediate-early genes are induced in similar regions of the mouse liver. p21 induction is not dependent on p53; we observed similar levels and localization of p21 in wild-type and p53 null animals. Immunohistochemical localization of p21 and CCAAT/enhancer-binding protein expression shows that p21 protein accumulation is limited to a subset of CCAAT/enhancer-binding protein-positive hepatocytes. A second peak of periportal and intermediate zone-specific p21 gene expression, appearing 1-2 days after injection, is also p53 independent and may represent cell cycle checkpoints or postmitotic growth arrest. Sporadic p21 expression was also detected in pairs of hepatocytes distributed throughout the liver acini in healthy animals. Together, these data suggest several roles for p21 in the liver in response to toxicity, regeneration, and growth inhibition.     

Cross-linked DNA duplexes--exonuclease stability and interaction with the nucleic transcription factor of the kappa light-chain enhancer (NF-kappaB)

This study documents the differences in kinetics of 2 h (n = 7) and 4 h (n = 9) of 1.25 minimum alveolar anesthetic concentration (MAC) of desflurane (9.0%) versus (on a separate occasion) sevoflurane (3.0%), both administered in a fresh gas inflow of 2 L/min. These data are extensions of our previous 8-h (n = 7) studies of these anesthetics. By 10 min of anesthetic administration, average inspired (F(I)) and end-tidal concentration (F(A)) (F(I)/F(A); the inverse of the more commonly used F(A)/F(I)) decreased to less than 1.15 for both anesthetics, with the difference from 1.0 nearly twice as great for sevoflurane as for desflurane. During all sevoflurane administrations, F(A)/F(I) for Compound A [CH2F-O-C(=CF2) (CF3); a vinyl ether resulting from the degradation of sevoflurane by Baralyme] equaled approximately 0.8, and the average inspired concentration equaled approximately 40 ppm. Compound A is of interest because at approximately 150 ppm-h, it can induce biochemical and histological evidence of glomerular and tubular injury in rats and humans. During elimination, F(A)/F(A0) for Compound A (F(A0) is the last end-tidal concentration during anesthetic administration) decreased abruptly to 0 after 2 h and 4 h of anesthesia and to approximately 0.1 (F(A) approximately 3 ppm) after 8 h of anesthesia. In contrast, F(A)/F(A0) for desflurane and sevoflurane decreased in a conventional, multiexponential manner, the decrease being increasingly delayed with increasing duration of anesthetic administration. F(A)/F(A0) for sevoflurane exceeded that for desflurane for any given duration of anesthesia, and objective and subjective measures indicated a faster recovery with desflurane. Times (mean +/- SD) to initial response to command (2 h 10.9 +/- 1.2 vs 17.8 +/- 5.1 min, 4 h 11.3 +/- 2.1 vs 20.8 +/- 4.8 min, 8 h 14 +/- 4 vs 28 +/- 8 min) and orientation (2 h 12.7 +/- 1.6 vs 21.2 +/- 4.6 min, 4 h 14.8 +/- 3.1 vs 25.3 +/- 6.5 min, 8 h 19 +/- 4 vs 33 +/- 9 min) were shorter with desflurane. Recovery as defined by the digit symbol substitution test, P-deletion test, and Trieger test results was more rapid with desflurane. The incidence of vomiting was greater with sevoflurane after 8 h of anesthesia but not after shorter durations. We conclude that for each anesthetic duration, F(I) more closely approximates F(A) with desflurane during anesthetic administration, F(A)/F(A0) decreases more rapidly after anesthesia with desflurane, and objective measures indicate more rapid recovery with desflurane. Finally, it seems that after 2-h and 4-h administrations, all Compound A taken up is bound within the body. Implications: Regardless of the duration of anesthesia, elimination is faster and recovery is quicker for the inhaled anesthetic desflurane than for the inhaled anesthetic sevoflurane. The toxic degradation product of sevoflurane, Compound A, seems to bind irreversibly to proteins in the body.     

Tumor necrosis factor receptor (TNFR)-associated factor 2A (TRAF2A), a TRAF2 splice variant with an extended RING finger domain that inhibits TNFR2-mediated NF-kappaB activation

We describe here the identification and characterization of tumor necrosis factor receptor (TNFR)-associated factor 2A (TRAF2A), a splice variant of the TRAF2 molecule utilized for signal transduction by members of the TNFR family. TRAF2A and TRAF2 cDNAs are identical in sequence with the exception of an extra 21 base pairs of sequence encoding a 7-amino acid insert within the TRAF2A RING finger domain. TRAF2A mRNA expression is regulated in a tissue-specific manner, with relative TRAF2A mRNA levels being highest in spleen and lowest in brain. TRAF2A protein is capable of binding to the cytoplasmic domain of TNFR2 (p75) and is detectable in T-lymphoma cells stably transfected with the TRAF2A cDNA. Unlike TRAF2, TRAF2A has a short half-life ( approximately 100 min) in these cells and is expressed at only low levels in transiently transfected COS-7 cells. However, TRAF2A levels in transiently transfected COS-7 cells approach those of TRAF2 upon coexpression with TRAF1 and/or TRAF2, indicating that TRAF2A stability is regulated by the binding of other TRAF family proteins. Also in contrast to TRAF2, TRAF2A is unable to stimulate NF-kappaB activity when overexpressed in 293 cells and acts as a dominant inhibitor of TNFR2-dependent NF-kappaB activation. TRAF2A thus represents a novel signal transduction protein, the expression of which can act to inhibit TRAF2-dependent NF-kappaB activation.     

Truncated SNAP-25 (1-197), like botulinum neurotoxin A, can inhibit insulin secretion from HIT-T15 insulinoma cells

We and others have previously shown that insulin-secreting cells of the pancreas express high levels of SNAP-25 (synaptosomal-associated protein of 25 kDa), a 206-amino acid t-SNARE (target soluble N-ethylmaleimide-sensitive factor attachment protein receptors) implicated in synaptic vesicle exocytosis. In the present study, we show that SNAP-25 is required for insulin secretion by transient transfection of Botulinum Neurotoxin A (BoNT/A) into insulin-secreting HIT-T15 cells. Transient expression of BoNT/A cleaved the endogenous as well as overexpressed SNAP-25 proteins and caused significant reductions in K+ and glucose-evoked secretion of insulin. To determine whether the inhibition of release was due to the depletion of functional SNAP-25 or the accumulation of proteolytic by-products, we transfected cells with SNAP-25 proteins from which the C-terminal nine amino acids had been deleted to mimic the effects of the toxin. This modified SNAP-25 (amino acids 1-197) remained bound to the plasma membrane but was as effective as the toxin at inhibiting insulin secretion. Microfluorimetry revealed that the inhibition of secretion was due neither to changes in basal cytosolic Ca2+ levels nor in Ca2+ influx evoked by K(+)-mediated plasma membrane depolarization. Electron microscopy revealed that cells transfected with either BoNT/A or truncated SNAP-25 contained significantly higher numbers of insulin granules, many of which clustered close to the plasma membrane. Together, these results demonstrate that functional SNAP-25 proteins are required for insulin secretion and suggest that the inhibitory action of BoNT/A toxin on insulin secretion is in part caused by the production of the plasma membrane-bound cleavage product, which itself interferes with insulin granule docking and fusion.     

Erinacin, an antihaemorrhagic factor from the European hedgehog, Erinaceus europaeus

An antihaemorrhagic factor named erinacin was purified from the skeletal muscle extract of the European hedgehog, Erinaceus europaeus, by ammonium sulfate precipitation followed by various steps of ion-exchange (DEAE-cellulose), absorption chromatography (hydroxylapatite), and gel filtration (cellofine gel). A 625-fold purification was achieved with an overall yield of 19% antihaemorrhagic activity. The protein effectively inhibited the activity of Bothrops jararaca venom haemorrhagin and did not inhibit the enzymatic activity of trypsin and chymotrypsin. Erinacin is a large molecule (about 1,000,000 mol. wt). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of two subunits: one with an apparent mol. wt of 35,000 forming a larger subunit (350,000) by cross-linking with disulfide bridges, and a second with a mol. wt of 39,000 without disulfides. Dissociation of erinacin into its subunits resulted in complete loss of its antihaemorrhagic activity.     

Expression of E1AF, an ets-family transcription factor, is correlated with the invasive phenotype of oral squamous cell carcinoma

PURPOSE: To assess the accuracy of intraarterial measurement of transstenotic pressure gradients for the detection of hemodynamically suboptimal iliac angioplasty. METHODS: In 14 patients, referred for diagnostic angiography, mean pressure gradients in the aorta and iliac artery were obtained twice, using a double-sensor pressure catheter. Additional iliac measurements were performed during pharmacologically induced flow augmentation. Repeatability was assessed by calculation of the mean difference plus standard deviation (MD +/- SD) and repeatability coefficient (2 x SD). These results were extrapolated to 137 iliac angioplasty procedures with secondary stenting where there was a residual pressure gradient > 10 mmHg. RESULTS: MD +/- SD for repeated measurements at rest and during flow augmentation were 0 +/- 2 mmHg and 1 +/- 3 mmHg, respectively. Repeatability coefficients were 3 and 6 mmHg. Mean pressure gradients after hemodynamically insufficient angioplasty were 8 +/- 7 mmHg at rest and 17 +/- 5 mmHg following vasodilatation. Inaccurate pressure recordings may have led to inappropriate stent placement in less than 2.5%, and inappropriate denial of stent placement in less than 5% of the lesions. CONCLUSION: Variability of intraarterial pressure measurements has little consequence in the detection of hemodynamically significant stenosis after angioplasty.     

Granulocyte colony-stimulating factor (CSF), macrophage-CSF, granulocyte-macrophage CSF, interleukin-3, and interleukin-6 levels in sera from children undergoing blood stem cell autografts

Endogenous production of granulocyte colony-stimulating factor (G-CSF), macrophage CSF (M-CSF), granulocyte-macrophage CSF (GM-CSF), interleukin-3 (IL-3), and interleukin-6 (IL-6) was investigated in 10 children who underwent a total of 12 courses of autologous peripheral blood stem cell transplant (PBSCT) by measuring their serum levels using immunoassay kits. The serum G-CSF level increased immediately following infusion of PBSC graft, peaked between days 3 and 7 posttransplant and then declined by the time the granulocyte count rose. No definitive association was found between the continuous high levels of G-CSF and infective episodes, the number of infused nucleated cells, monocytes, CFU-GM, or the number of days required to achieve greater than 0.5 x 10(9)/L granulocyte, greater than 1.0 x 10(9)/L leukocyte, or greater than 50 x 10(9)/L platelet counts. After PBSCT, IL-6 levels tended to be elevated. No detectable serum level of GM-CSF or IL-3 (< 50 pg/mL) was observed before PBSCT and 4 patients showed a transient increase in the GM-CSF level after PBSCT. No significant change was observed in the post-transplant serum levels of IL-3 or M-CSF. The role of endogenously secreted cytokines in early hematopoietic recovery after PBSCT needs further clarification, but, at present, routine use of exogenous G-CSF therapy is not recommended.     

Extracellular truncations of h beta c, the common signaling subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-5, lead to ligand-independent activation

The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c-derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid-specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling.     

Helminths of the Canadian toad, Bufo hemiophrys (Amphibia: Anura), from Alberta, Canada

Forty adult Bufo hemiophrys from Alberta, Canada, were examined for helminths. Four species were found: a trematode, Gorgoderina simplex, and 3 nematodes, Cosmocercoides variabilis, Oswaldocruzia pipiens, and Rhabdias americanus. Rhabdias americanus had the highest prevalence of helminths (73%); C. variabilis had the highest mean intensity (26+/-33 SD). Bufo hemiophrys represents a new host record for each species of helminth.     

Interferon (IFN) consensus sequence-binding protein, a transcription factor of the IFN regulatory factor family, regulates immune responses in vivo through control of interleukin 12 expression

Mice with a null mutation of the gene encoding interferon consensus sequence-binding protein (ICSBP) develop a chronic myelogenous leukemia-like syndrome and mount impaired responses to certain viral and bacterial infections. To gain a mechanistic understanding of the contributions of ICSBP to humoral and cellular immunity, we characterized the responses of control and ICSBP-/- mice to infection with influenza A (flu) and Leishmania major (L. major). Mice of both genotypes survived infections with flu, but differed markedly in the isotype distribution of antiflu antibodies. In sera of normal mice, immunoglobulin (Ig)G2a antibodies were dominant over IgG1 antibodies, a pattern indicative of a T helper cell type 1 (Th1)-driven response. In sera of ICSBP-/- mice, however, IgG1 antibodies dominated over IgG2a antibodies, a pattern indicative of a Th2-driven response. The dominance of IgG1 and IgE over IgG2a was detected in the sera of uninfected mice as well. A seeming Th2 bias of ICSBP-deficient mice was also uncovered in their inability to control infection with L. major, where resistance is known to be dependent on IL-12 and IFN-gamma as components of a Th1 response. Infected ICSBP-deficient mice developed fulminant, disseminated leishmaniasis as a result of failure to mount a Th1-mediated curative response, although T cells remained capable of secreting IFN-gamma and macrophages of producing nitric oxide. Compromised Th1 differentiation in ICSBP-/- mice could not be attributed to hyporesponsiveness of CD4(+) T cells to interleukin (IL)-12; however, the ability of uninfected and infected ICSBP-deficient mice to produce IL-12 was markedly impaired. This indicates that ICSBP is a deciding factor in Th responses governing humoral and cellular immunity through its role in regulating IL-12 expression.