Serum matrix metalloproteinase 7 levels identifies poor prognosis advanced colorectal cancer patients

Metalloproteinase 7 (MMP-7) plays an important role in tumor growth, invasion and dissemination, and is secreted to the media. Because of the close implication of MMP-7 in cancer biology, we sought to define the prognostic significance of serum levels of MMP-7 in metastatic colorectal cancer (CRC) and explore its possible impact in the daily clinical practice. MMP-7 expression was determined by enzyme-linked immunoabsorbent assay. We assessed serum MMP-7 levels in 87 healthy controls, 96 patients with nonmetastatic CRC and 120 patients with advanced CRC. Clinical information was gathered from patient files. Cox proportional hazards model was used to assess survival. MMP-7 and the variables associated with prognosis were entered and a backward elimination method was employed to adjust the model. Inclusion criteria was p /= 0.10. Advanced CRC patients have a significant higher mean serum MMP-7 levels (13.4 ng/ml) than those in nonmetastatic CRC (5.5 ng/ml; p < 0.001) and healthy controls (4.2 ng/ml; p < 0.001). In metastatic patients, after adjusting for other prognostic variables, MMP-7 (entered as a continuous variable) is associated with decreased survival (HR 1.016, IC 95% 1.002-1.031). Serum MMP-7 levels are significantly elevated in patients with advanced CRC. In conclusion, MMP-7 is an independent prognostic factor for survival in advanced CRC. In our sample, the risk of death associated to MMP-7 increase is much higher than the risk of death associated to lactate dehydrogenase elevation.     

Internalization of tissue factor by platelets

Tissue factor (TF) has been found associated with platelets. Mechanisms responsible for TF-platelet interactions and transport are not fully understood. We explored the response of isolated washed platelets to preparations of recombinant (rTF) or placental (pTF) human TF, exposed on lipid microvesicles (MVs). Sequential ultrastructural and immunocytochemical studies revealed trafficking of these TF preparations, being endocytosed by platelets into channels of the open canalicular system (OCS) and accumulating in the cytoplasm and occasionally in alpha-granules. The process of internalization of TF-MVs was accomplished in less than 30 min, being faster for the placental (pTF) than for the recombinant (rTF) preparation. Signs of mild platelet activation with pseudopodia formation were observed at early stages of internalization. Platelets returned to an apparent resting state after 5-10 min. All of these observations paralleled with modifications on patterns of tyrosine phosphorylation for several signaling proteins. Our studies demonstrate that platelets possess mechanisms to capture and incorporate TF-rich vesicles. These processes were accelerated by the presence of other contaminating cellular antigens in the vesicles (pTF). TF carried by platelets could play a potential role in platelet thrombus formation and by extension in the development of ischemic complications.     

Inhibition of tyrosine kinase activity prevents the adhesive and cohesive properties of platelets and the expression of procoagulant activity in response to collagen

Introduction

Platelet activation leads to signal transduction mechanisms, in which phosphotyrosine proteins play a relevant role.

Material and methods

Platelet suspensions were independently activated by collagen and thrombin in the absence and in the presence of two tyrosine kinase inhibitors, tyrphostin 47 and genistein. Samples were processed to visualize morphological changes by electron microscopy, to evaluate changes in cytoskeletal assembly, to analyze modifications in the expression of activation dependent antigens, and the procoagulant activity at the surface level by flow cytometry. Additional experiments applying flow conditions were performed to assess the effect of inhibiting tyrosine phosphorylation on primary platelet adhesion and fibrin formation.

Results

Inhibition of tyrosine phosphorylation blocked shape change and cytoskeletal assembly induced by collagen, and inhibited, though partially, those effects due to thrombin. Both activating agents induced the expression of the intraplatelet antigens CD62P and CD63 at the surface, although only collagen promoted expression of anionic phospholipids. Both tyrphostin 47 and genistein prevented those effects. The extent of platelet adhesion on both collagen-coated and subendothelial surfaces was significantly diminished by the presence of the tyrosine kinase inhibitors assayed. Fibrin formation was also significantly reduced.

Conclusions

Platelet shape change and secretion during platelet activation depends on tyrosine phosphorylation. In addition, primary adhesion of platelets induces signaling through tyrosine kinases to achieve full spreading, and results in the exposure of a procoagulant surface on platelets.     

Inhibitory effect of CDP, a polysaccharide extracted from the mushroom Collybia dryophila, on nitric oxide synthase expression and nitric oxide production in macrophages

The effect of Collybia dryophila polysaccharide (CDP), a (1-->3), (1-->4)-beta-D-glucan extracted from the mushroom C. dryophila, was evaluated on nitric oxide (NO) production induced by lipopolysaccharide (LPS) and gamma interferon (IFNgamma) or by LPS alone in RAW 264.7 cells. CDP significantly inhibited NO production in a dose-dependent manner without affecting cell viability. The inhibition of NO by CDP was consistent with decreases in both inducible nitric oxide synthase (iNOS) protein and mRNA expression suggesting that CDP exerts its effect by inhibiting iNOS gene expression. In addition, CDP at concentrations of 400 and 800 microg/ml was shown to significantly increase prostaglandin E2 (PGE2) production in LPS- and IFNgamma-induced macrophages when compared to the control.     

Phosphorylated FTY720 stimulates ERK phosphorylation in astrocytes via S1P receptors

Sphingosine-1-phosphate receptors (S1P1-5) are activated by the endogenous agonist S1P and are expressed in the central nervous system. In astrocytes, activation of S1P receptors leads to phosphorylation of extracellular-signal regulated kinase (ERK), a signaling cascade which plays intimate roles in cell proliferation. Fingolimod (FTY720) is in phase III clinical trials for the treatment of multiple sclerosis and its phosphorylated version (FTY720P) activates S1P receptors. We examined the effects of FTY720P on ERK phosphorylation and determined which S1P receptor subtype(s) mediated this signaling event. FTY720P augmented ERK phosphorylation in cortical cultures prepared from embryonic day 18 rat brains and was blocked by an MEK inhibitor or by pertussis toxin. Co-localisation of phosphorylated ERK occurred in glial fibrillary acidic protein (GFAP) positive astrocytes but not neurons or oligodendrocytes. Furthermore, FTY720P stimulated ERK phosphorylation in highly enriched astrocyte cultures made from postnatal day 2 rat cortices. The effects of FTY720P were mimicked by selective S1P1 receptor agonists and blocked by S1P1 receptor antagonists. Collectively, these results demonstrate that FTY720P mediates ERK phosphorylation in astrocytes via the activation of S1P1 receptors.     

Constrictive pericarditis and restrictive myocardiopathy]

The purpose of this study was to assess the clinical and echocardiographic characteristics of constrictive pericarditis (CP) and restrictive cardiomyopathy (RC) and to compare them with the results obtained with cardiac catheterization. Clinical history, electrocardiogram and X-ray were taken in all patients, and transthoracic and transesophageal echocardiography were performed. Cardiac catheterization with transmyocardial biopsy was performed on only 5 patients. Wall thickness and left ventricular dimensions were normal in all patients with CP. Wall thickness was increased in those with RC. No patients demonstrated alterations in segmental wall movement. The pericardium was thickened and abnormally bright in the 3 patients with CP. In patients with CP the percentage of atrioventricular, semilunar, pulmonary and hepatic flow changes with respiration were more than 10%. In patients with RC this flow variation was less notable. However, the percentage of systolic and diastolic flow velocity increase of hepatic veins during expiration was greater than in CP. We can conclude that M-mode, two dimensional and Doppler echocardiography is extremely useful noninvasive method to differentiate CP and RC with good correlation with cardiac catheterization.     

Distribution of descending projections from primary auditory neocortex to inferior colliculus mimics the topography of intracollicular projections

To ascertain whether the auditory neocortex also innervates the central nucleus of the inferior colliculus (CNIC) and not only its dorsal (DCIC) and external (ECIC) cortices, the anterograde tracers Phaseolus vulgaris-leucoagglutinin (PHA-L) and biotinylated dextran (BD) were injected into the primary auditory neocortex of albino rats (Te1), and labeled corticocollicular fibers were studied via light and electron microscopy. Axons from discrete regions of Te1 form two rostrocaudally oriented laminar plexuses of terminal fibers in the ipsilateral inferior colliculus (IC) and one in the contralateral IC. The first ipsilateral plexus, located in the medial half of the IC, has a dorsomedial to ventrolateral orientation, parallel to the isofrequency planes of the IC; is continuous through the CNIC and DCIC; and extends into the rostral ECIC. The second plexus is located in the deep layers of the lateral ECIC. These two plexuses meet caudally and ventrally, at the border between the CNIC and the lateral ECIC. The plexus in the contralateral IC is less dense and shorter than the two ipsilateral plexuses and is symmetric to the medial plexus. The thickness of the three plexuses is correlated with the size of the injection site, and their mediolateral and dorsoventral positions change as the injection site in Te1 is displaced rostrocaudally, with more caudal injections resulting in more dorsolateral medial plexuses and more dorsomedial lateral plexuses. Furthermore, the ventromedial border of the IC receives nontopographic, convergent projections from wide regions of rostral portions of Te1. The distribution of these corticocollicular plexuses mimics the topography of previously described intracollicular fibers. Electron microscopy shows that, in all three subdivisions of the ipsilateral IC, corticocollicular fibers form small boutons with features generally associated with excitatory transmission; i.e., they contain round synaptic vesicles and form asymmetric synapses with thin dendritic shafts and spines. These results demonstrate that the auditory corticocollicular projections innervate more extensive regions of the IC than were previously observed. Although peripheral regions receive the densest projection, the entire IC appears to be the target of corticofugal input. © 1996 Wiley-Liss, Inc.     

Association between severe hypoglycaemia and risk of dementia in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

The aim of this systematic review was to analyse whether there is an association between severe hypoglycaemia and the incidence of dementia in patients with type 2 diabetes mellitus. We systematically searched the MEDLINE, Scopus, and Cochrane databases from their inception until September 2022 for observational studies on the association between hypoglycaemia and the risk of dementia. The DerSimonian and Laird method was used to compute a pooled estimate of the risk for such association. Risk ratio (RR) and its respective 95% confidence interval (95% CI). Two analyses were performed to estimate the risk of dementia: (i) any hypoglycaemia versus no hypoglycaemia and (ii) a dose–response analysis for one, two, or more than three hypoglycemic events versus no hypoglycaemia. PROSPERO registration number CRD42020219200. Seven studies were included. The pooled RR for the association of severe hypoglycaemia and risk of dementia was 1.47 (95% CI: 1.24–1.74). When the dose–response trend was analysed, the pooled RR for the risk of dementia was increased according to the hypoglycaemia events as follows: 1.29 (95% CI: 1.15–1.44) for one hypoglycemic event; 1.68 (95% CI: 1.38–2.04) for two hypoglycemic events; and 1.99 (95% CI: 1.48–2.68) for three or more hypoglycemic events. Our study demonstrates a 54% higher risk of dementia among people who suffer a hypoglycaemia event compared to nonhypoglycaemia. Considering our results and the prevalence of people suffering from diabetes mellitus, health education for both newly diagnosed and already diagnosed people could be a useful tool for glycaemic control, thus avoiding hypoglycaemic events.