The role of oral anticoagulants in epistaxis.

PURPOSE: The purpose of this retrospective study was to identify the impact of oral anticoagulants on epistaxis with the focus on new oral anticoagulants. METHODS: The study was conducted at the Department  for Ear- Nose- and Throat (ENT), Head and Neck Surgery, Technical University Munich, Germany. All patients presenting in 2014 with the diagnosis of epistaxis to a specialized ENT accident and emergency department were identified and analyzed in clinical data and medication. RESULTS: 600 adult cases, with a median age of 66.6 years were identified with active bleeding. 66.8% of all cases were anticoagulated. Classic oral anticoagulants (COAC) were three times more common in patients than new-generation oral anticoagulants (NOAC). Recurrent bleeding was significantly associated with oral anticoagulants (OAC) (p = 0.014) and bleeding location was most often anterior (p = 0.006). In contrast, severe cases, which required surgery or embolization were significantly more likely in non-anticoagulated middle-aged patients with posterior bleedings (p < 0.05). In our epistaxis cohort, OAC were highly overrepresented (40%) when compared to the general German population (1%) but COAC as well as NOAC played only a minor role in severe courses of epistaxis. CONCLUSION: Oral anticoagulation, especially with new-generation drugs, is not associated with more complicated and severe courses of epistaxis, but rather with recurrent bleeding. One should keep this information in mind when triaging the patient in the emergency room and when planning further procedures.

Interleukin-4 and interferon-γ orchestrate an epithelial polarization in the airways.

Interferon-γ (IFN-γ) and interleukin-4 (IL-4) are key effector cytokines for the differentiation of T helper type 1 and 2 (Th1 and Th2) cells. Both cytokines induce fate-decisive transcription factors such as GATA3 and TBX21 that antagonize the polarized development of opposite phenotypes by direct regulation of each other's expression along with many other target genes. Although it is well established that mesenchymal cells directly respond to Th1 and Th2 cytokines, the nature of antagonistic differentiation programs in airway epithelial cells is only partially understood. In this study, primary normal human bronchial epithelial cells (NHBEs) were exposed to IL-4, IFN-γ, or both and genome-wide transcriptome analysis was performed. The study uncovers an antagonistic regulation pattern of IL-4 and IFN-γ in NHBEs, translating the Th1/Th2 antagonism directly in epithelial gene regulation. IL-4- and IFN-γ-induced transcription factor hubs form clusters, present in antagonistically and polarized gene regulation networks. Furthermore, the IL-4-dependent induction of IL-24 observed in rhinitis patients was downregulated by IFN-γ, and therefore IL-24 represents a potential biomarker of allergic inflammation and a Th2 polarized condition of the epithelium.

Inhibition of NGF-induced neurite outgrowth of rat pheochromocytoma cells (PC12) following administration of dioxyamphetamine.

Amphetamine analogs are known to induce not only neurotoxicity at serotonergic axon terminals but also neocortical neuronal degeneration. However, a much less studied aspect involves the impact of amphetamine exposure on neuronal development. The present study investigated whether pretreatment of PC12 cells with dioxyamphetamine (DA) alters differentiation of PC12 cells by NGF and, if so, which components of the Ras/Raf/MEK/ERK pathway known to be involved in the differentiation response to NGF are particularly affected. Though exposure of PC12 cells to DA 1h prior to NGF treatment resulted in apopotosis, several PC12 cells survived. However, neurite outgrowth of these NGF-responsive cells was repressed. Immunoblots of whole cell extracts revealed a strong induction rather than inhibition of ERK phosphorylation up to 48h after DA/NGF treatment. Our results indicate that NGF-mediated neurite outgrowth was inhibited by pretreatment with DA, and this blockage of NGF-induced neuritogenesis was not due to an inhibition of ERK phosphorylation.

The Akt/protein kinase B-dependent anti-apoptotic pathway and the mitogen-activated protein kinase cascade are alternatively activated in human glioblastoma multiforme.

We investigated the activation of two important signal transduction pathways in human glioblastoma cells and found a constitutive phosphorylation of either Akt or mitogen-activated protein kinase (MAPK) under serum free conditions. In all but one cell line Wortmannin-sensitive activation of Akt could be attributed to the loss of functional PTEN protein. All cell lines with Akt activation exhibited only weak phosphorylation of the MAPK signal pathway, whereas those without constitutive Akt activation demonstrated high levels of phosphorylated MAPK under serum free conditions. Our data might indicate the presence of two functional subtypes of glioblastoma multiforme, since Akt and MAPK are involved in cellular survival and proliferation signalling, respectively.

Molecular genetic characterisation of intracerebrally transplanted brain tumours.

The aim of the present study was the characterisation of genetic alterations in two different experimental gliomas, induced in rats from the inbred strain BDIX by transplacental ethylnitrosourea with subsequent serial transplantation. The genes investigated have been shown previously to be altered during human glial tumour progression and include the gene for the epidermal growth factor receptor (EGFR), the genes for the cell cycle regulators cyclin dependent kinase 4 (CDK4), cyclinD1 (cycD1), the p16 gene (MTS1/INK4) and the retinoblastoma gene (RB). Using a semi-quantitative PCR-based screening method no gross alterations could be detected in these genes, demonstrating that nitrosourea-induced glial tumours of rats do not harbour those genetic changes which typically arise in human malignant gliomas. Thus, the use of this tumour model for gene therapy trials is questionable.

The p16/Cdkn2a/Ink4a gene is frequently deleted in nitrosourea-induced rat glial tumors.

The present study investigates nitrosourea-induced rat (Rattus norvegicus) glioma cell lines for the functional status of the p16/Cdkn2a/Ink4a gene, which encodes the p16 cdk4 inhibitor and the alternative reading frame protein, p19ARF. We detected homozygous deletions of the p16/Cdkn2a/Ink4a gene locus in 4 of 5 glioma cell lines (C6, F98, RG2, and RGL.3), but not in the 9L gliosarcoma cell line or in a rat primary fibroblast cell line. RT-PCR demonstrated expression of the p16 and p19ARF mRNAs only in 9L cells and in rat fibroblasts. Comparative genomic in situ hybridization showed that the copy number of rat chromosome RNO5 was not altered in any of the glioma cell lines investigated, indicating that the deletions result from a discrete loss in the region of the p16/Cdkn2a/Ink4a locus. This is the first report of p16/Cdkn2a/Ink4a deletions present in nitrosourea-induced rat glioma cell lines. Since this genetic alteration is also commonly observed in human malignant glial tumors, our results validate the use of chemically induced rat glioma cell lines as an experimental model in the development of gene therapy strategies.

Selective rejection of H-2-deficient lymphoma variants suggests alternative immune defence strategy.

Metazoan organisms may discriminate between self and non-self not only by the presence of foreign antigens but also by the absence of normal self markers. Mammalian adaptive immune responses use the first strategy, with the additional requirement that foreign antigens are recognized in the context of self-major histocompatibility complex (MHC) products at the cell surface. Aberrant cells which fail to express MHC products adequately can therefore avoid detection. A more primitive but complementary defence system, eliminating such cells on the basis of absent self-markers, is suggested by a re-interpretation of phenomena associated with metastasis and natural resistance. We now show that murine lymphoma cells selected for loss of H-2 expression are less malignant after low-dose inoculation in syngeneic hosts than are wild-type cells, and that the rejection of such cells is non-adaptive. On the basis of our data, we suggest that natural killer cells are effector cells in a defence system geared to detect the deleted or reduced expression of self-MHC.

YAC-1 MHC class I variants reveal an association between decreased NK sensitivity and increased H-2 expression after interferon treatment or in vivo passage.

Two H-2 negative variants of the YAC-1 lymphoma were selected by mutagenization and sequential in vitro selections and compared with wild-type cells for changes in NK sensitivity and H-2 expression after interferon treatment or in vivo passage. The H-2 negative variants and the low H-2 expressor YAC-1 wild-type cells had similar NK sensitivity. However, IFN-beta or recombinant IFN-gamma pretreatments increased the H-2 expression of YAC-1 and protected them from NK lysis, whereas the H-2 variants, which remained H-2 negative, were not protected and often more sensitive to NK lysis. The H-2 variants were similarly susceptible as wild-type cells to three other cellular effects of interferon: protection from virus infection, modulation of Con A capping, and inhibition of cell proliferation. Thus, the only interferon-mediated effect that distinguished the H-2 negative variants from wild-type cells was the inability of the former to increase their H-2 expression and decrease their NK sensitivity. The wild-type YAC-1 line showed increased H-2 expression and decreased NK sensitivity after in vivo passage. In contrast, in vivo passaged H-2 variants showed no reexpression of H-2, and remained NK sensitive. The altered responses to interferon and in vivo passage were specific for loss or down-regulation of H-2, because Thy-1 loss (H-2 positive) YAC-1 variants behaved as the wild-type cells in all respects. This study supports the hypothesis that NK cells may function in vivo to eliminate host cells that fail to express H-2 after interferon stimulation during an immune response; such cells are a potential threat because they may escape recognition by T lymphocytes despite the expression of viral or tumor-associated antigens.

Induction of K562 lysis in autologous LGL and dense T cell cocultures.

Human large granular lymphocytes (LGL) were cultured with autologous dense T lymphocytes for 0-8 days. The mixed LGL dense T cell cultures had enhanced lytic activity against K562 on day 4, as compared to LGL cultured alone. Dense T cells cultured alone had no K562 lytic activity. The mixed LGL dense T cell cultures were reseparated on day 4 into low dense SRBC- and SRBC+ and into high dense subsets. Both low dense subsets did lyse K562 whereas the high dense subset did not lyse K562. Since the LGL population was the low dense SRBC- cells, the results suggested that the day 4 low dense SRBC+ cytotoxic population in the mixed LGL dense T cell culture originated from noncytotoxic dense T cells. Dense T cells were also separated into OKT8- and OKT8+ subsets and cultured together with LGL for 0-8 days. The LGL dense OKT8- T cell coculture had enhanced K562 lytic activity while the LGL dense OKT8+ T cell coculture had no enhanced lytic activity, as compared to LGL cultured alone. These results indicated that LGL interacted with the dense OKT8- T cells to produce the enhanced K562 lysis.

NK-patterned binding expressed by non-NK mouse leukocytes.

Previous studies demonstrated that NK-cell-enriched spleen cells bind to sensitive but not to resistant mouse lymphoma targets, measured by a single-cell target binding assay. In the present report we further analyzed this "NK-patterned" binding using effector cells with high, low or no NK activity. In agreement with previous results, nylon-wool-passed spleen cells as well as a cloned cytotoxic cell line with NK activity bound tumor targets largely according to their NK sensitivity; NK-sensitive tumors had a higher frequency of binders than the more resistant ones. The correlation coefficient relating the percentage target binding cells (TBC) for each tumor with the ability of the same tumor to inhibit lysis in cold target competition assays was consistently higher than that relating percentage TBC with direct NK lysis. A non-lytic variant of the cloned cytotoxic cell line had a binding pattern identical to that of the lytic line, demonstrating that "NK-patterned" binding occurred in the absence of lysis. Thymocytes, which are totally devoid of NK activity, also bound preferentially NK-sensitive targets, and their binding was decreased after trypsin treatment or in the presence of EDTA. Peritoneal macrophages also showed "NK-patterned" binding, thus demonstrating that this was not restricted to cells in the T-cell lineage. Variants from a mouse lymphoma selected for decreased NK sensitivity bound a lower frequency of NK-active (nylon-wool-passed spleen cells) and inactive cells (thymocytes, peritoneal macrophages). This study therefore showed that the membrane property conferring NK-binding selectivity exists on several types of non-NK leukocytes.

Responses of normal and malignant cells to collagen, collagen-derived peptides and the C5-related tumor cell chemotactic peptide.

Two variant subpopulations of murine fibrosarcoma cells that differ significantly in their malignant potential and normal mouse fibroblasts were compared with regard to ability to respond chemotactically to collagen, collagen-derived peptides and the C5-derived tumor cell chemotactic peptide. Two distinct patterns of responsiveness were observed. The normal fibroblasts and non-metastasizing fibrosarcoma cells responded to the collagen products but not the C5 peptide. The metastasizing fibrosarcoma cells responded to the C5 peptide but not to the collagen products. These findings emphasize the similarities between the normal fibroblasts and the non-metastasizing fibrosarcoma cells.

Characteristics of the chemotactic factor-mediated cell swelling response of tumor cells.

The interaction between Walker carcinosarcoma cells, maintained in ascites form in noninbred Sprague-Dawley rats and in cell culture, and appropriate factors induced directed migration (chemotaxis) of these cells as measured in the Boyden chamber assay. The response of the tumor cells to these factors was very similar to that of leukocytes to their chemotactic factors. In addition to inducing chemotactic responses, the interaction between Walker carcinosarcoma cells and appropriate chemotactic factors also led to a swelling of the cells, which could be measured with the use of Coulter Channelyzer C-1000. Associated with the cell-swelling response was a temporary drop in the cell count of a suspension of cells as measured with the use of a Coulter counter, model ZBI. These responses were also similar to what occurs when leukocytes interact with their chemotactic factors. When the suspension of tumor cells was pretreated with 2-deoxyglucose, the responses measured with the Coulter counters were almost completely abrogated. In contrast to this, treatment of the cells with various chemical agents, including cytochalasin B, colchicine, cycloheximide, chlorpromazine, and the Ca2+ ionophore A23187 failed to significantly reduce the cell-swelling response. Cytochalasin B slightly potentiated the response. These similarities to the responses of leukocytes suggested a common underlying mechanism.

Chemotactic factor-induced adherence of tumor cells.

Two peptides which have previously been shown to induce chemotactic motility in a number of tumor cells were tested for their ability to alter the adhesiveness of Walker Carcinosarcoma cells (A chemotactically-responsive rat tumor) and normal rat fibroblasts (which have previously been shown to be chemotactically nonresponsive). Adherence of the tumor cells to nylon fibers was increased in a dose-dependent manner by the two active peptides. Adherence of the fibroblasts was not increased. Nonchemotactic peptide analogues of the two active peptides did not alter the adherence of either cell type. The increased adhesiveness to foreign surfaces may contribute to the chemotactic response.