Antithrombotic activity of TNF-alpha

Basic and clinical observations suggest that thrombosis and inflammation are closely related. Here we addressed the role played by TNF-alpha in thrombus formation and growth in an in vivo mouse model. Using intravital microscopy, we show that systemic administration of TNF-alpha at doses found in sepsis transiently inhibits thrombus formation and delays arterial occlusion upon vascular injury. These results were reflected in a prolonged bleeding time. Platelets isolated from the TNF-alpha-treated mice showed a marked decrease in fibrinogen binding and P-selectin expression as well as reduced platelet aggregation in response to various agonists. In contrast, in vitro treatment of platelets with TNF-alpha did not affect their function. TNF receptor 1- and 2-deficient mice exhibited normal thrombogenesis in the presence of TNF-alpha. Additionally, the inhibitory effect of TNF-alpha was lost either after treatment with NG-monomethyl-l-arginine, an inhibitor of NO production, or in mice deficient for iNOS. These results indicate that under inflammatory conditions, when leukocytes need free passage to transmigrate into tissues, TNF-alpha decreases platelet activation and inhibits thrombi formation. This effect is not exerted directly on platelets but mediated through the rapid generation of NO in the vessel wall.     

Effect of Methadone Dose on Cocaine Abuse in a Methadone Program

The effect of methadone dose on cocaine abuse in methadone-maintained patients was examined in two protocols at separate treatment sites in the Yale Department of Psychiatry. In one protocol, methadone dose was lowered in response to each cocaine-positive urine and raised to a maximum of 70 mg in response to abstinence (negative urine toxicology screen for 2 weeks). Of 22 patients treated under this protocol, 33% stopped cocaine use for a minimum of 2 weeks. In a second protocol, methadone dose was raised in response to each cocaine-positive urine to a maximum dose of 120 mg qd. Ten patients have entered this protocol to date, and 8 responded to this treatment by stopping cocaine abuse for a minimum of 2 weeks. Thus, the increasing methadone dose contingency treatment was more effective (80% vs. 33%, P = 0.02, Fisher's Exact Test).     

Nur77 converts phenotype of Bcl-B, an antiapoptotic protein expressed in plasma cells and myeloma

Defects in apoptosis mechanisms play important roles in malignancy and autoimmunity. Orphan nuclear receptor Nur77/TR3 has been demonstrated to bind antiapoptotic protein Bcl-2 and convert it from a cytoprotective to a cytodestructive protein, representing a phenotypic conversion mechanism. Of the 6 antiapoptotic human Bcl-2 family members, we found that Nur77/TR3 binds strongest to Bcl-B, showing selective reactivity with Bcl-B, Bcl-2, and Bfl-1 but not Bcl-X(L), Mcl-1, or Bcl-W. Nur77 converts the phenotype of Bcl-B from antiapoptotic to proapoptotic. Bcl-B is prominently expressed in plasma cells and multiple myeloma. Endogenous Bcl-B associates with endogenous Nur77 in RPMI 8226 myeloma cells, where RNA interference experiments demonstrated dependence on Bcl-B for Nur77-induced apoptosis. Furthermore, a Nur77-mimicking peptide killed RPMI 8226 myeloma cells through a Bcl-B-dependent mechanism. Because Bcl-B is abundantly expressed in plasma cells and some myelomas, these findings raise the possibility of exploiting the Nur77/Bcl-B mechanism for apoptosis for eradication of autoimmune plasma cells or myeloma.     

Growth factor-independent proliferation of rat mammary carcinoma cells by autocrine secretion of neu-differentiation factor/heregulin and transforming growth factor-α

Serially transplantable rat mammary tumor (RMT) cells are not dependent on exogenous epidermal growth factor (EGF) and insulin-like growth factor-I for continuous growth in serum-free medium. Previously, we found that conditioned medium obtained from these cells contained EGF-like mitogenic activity and stimulated tyrosine phosphorylation of a 185-kDa protein in EGF-dependent mammary epithelial cells. This protein is distinct from the EGF receptor and resembles a 185-kDa tyrosine-phosphorylated protein present in RMT cells themselves. The results of the studies reported here indicate that the tyrosine-phosphorylated p185 detected in growth factor-independent RMT cells and in human mammary epithelial cells exposed to RMT-conditioned medium was activated erbB-2 protein. Partial purification of the activating factor present in RMT-conditioned medium yielded a heparin-binding growth factor with biochemical properties similar to those of neu differentiation factor/heregulin (NDF/HRG). RNA-polymerase chain reaction analysis demonstrated that RMT cells expressed mRNA for NDF/HRG, and western-blot analysis confirmed the presence of the 45-kDa secreted form of NDF/HRG in conditioned medium from the growth factor-independent RMT cells. The biological activity of partially purified rat NDF/HRG was examined and found to be the same as that of the pure growth factor. In addition, we found that RMT-conditioned medium, fractionated on an anion-exchange column and by reverse-phase high-pressure liquid chromatography, contained a potent EGF-like growth factor that was distinct from NDF/HRG. This factor competes with ¹²⁵I-EGF for binding to EGF receptors and has an apparent molecular mass of 6600 Da. This factor copurifies by high-pressure liquid chromotography with pure transforming growth factor-α (TGF-α), and the cells are positive for TGF-α mRNA. Thus, growth factor-independent RMT cells also synthesize and secrete TGF-α. These results indicate that growth factor-independent RMT cells secrete two growth factors with overlapping biological activities and suggest that autocrine loops mediated by these factors are important in the growth factor-independent proliferation of the RMT cells. © 1996 Wiley-Liss, Inc.     

Distribution of myocilin and extracellular matrix components in the corneoscleral meshwork of human eyes

PURPOSE: To examine ultrastructurally the composition of major extracellular matrix (ECM) components and the distribution of myocilin in the trabecular lamellae of corneoscleral (CS) meshwork in normal human eyes. The codistribution of myocilin with ECM components was also investigated. METHODS: Postembedding immunoelectron microscopic studies were performed with antibodies against myocilin and other ECM components, including fibronectin, laminin, vitronectin, tenascin, elastin, fibrillin-1, microfibril-associated glycoprotein (MAGP)-1, decorin, versican, hyaluronic acid, and five types of collagen (I, III, IV, V, and VI). Double labeling of myocilin with other ECM components was performed with different sized gold particles. RESULTS: In the trabecular beams of CS meshwork, fibronectin, laminin, and collagen type IV were associated with basement membranes, whereas elastin was specifically localized to the core of elastic-like fibers. Several types of collagens, glycoproteins, proteoglycans, and hyaluronic acid were detected both in the collagen fibers and ground substances. Myocilin predominantly localized in the long-spacing collagens and sheath materials surrounding elastic-like fibers, codistributed with fibronectin, fibrillin-1, MAGP-1, decorin, and type VI collagen. CONCLUSIONS: This study illustrated the composition of ECM materials in the trabecular lamellae of CS meshwork. Myocilin was specifically localized to long-spacing collagens and the surrounding sheath of elastic-like fibers interacting with microfibril-associated elements where changes have been documented to occur in glaucomatous and aging eyes.     

PML risk is the main factor driving the choice of discontinuing natalizumab in a large multiple sclerosis population: results from an Italian multicenter retrospective study

Journal of Neurology - Natalizumab (NTZ) is an effective treatment for relapsing–remitting multiple sclerosis (RRMS). However, patients and physicians may consider discontinuing NTZ therapy...     

Determinants of COVID-19-related lethality in multiple sclerosis: a meta-regression of observational studies

Journal of Neurology - To identify risk factors for an increased lethality of COVID-19 in patients with multiple sclerosis (MS). We searched scientific databases to identify cohort studies with the...     

Predicting functional impairment trajectories in amyotrophic lateral sclerosis: a probabilistic,multifactorial model of disease progression

Journal of Neurology - To employ Artificial Intelligence to model, predict and simulate the amyotrophic lateral sclerosis (ALS) progression over time in terms of variable interactions, functional...