Intraneuronal immunoreactivity for the prion protein distinguishes a subset of E200K genetic from sporadic Creutzfeldt-Jakob Disease

Recently, we reported widespread intraneuronal prion protein (PrP) immunoreactivity in genetic Creutzfeldt-Jakob disease (CJD) associated with the E200K mutation. Here, we evaluated 6 cases ofsporadic CJD MM type 1, 5 MV type 2, and 7 VV type 2 and compared their anatomical appearance with that of 29 E200K genetic CJD (gCJD) cases. We also performed double immunolabeling for ubiquitin, p62, early endosomal marker rab5, and immunogold electronmicroscopy in 3 cases. We identified 4 morphological types of intraneuronal PrP immunoreactivity: one type, defined as multiple globular structures, was significantly associated with a subset of E200K gCJD cases and was distinct from the intraneuronal small dotlike PrP immunoreactivity seen in sporadic CJD. Whereas the latter colocalized with rab5, there were single large (7.5 μm-15 μm) globular inclusion body-like structures detected predominantly but not exclusively in E200K gCJD; these were immunoreactive in part for ubiquitin and p62 and showed focal γ-tubulin immunoreactivity, suggesting aggresome features. Ultrastructural examination using immunogold revealed PrP localization in aggresome-like structures and in autophagic vacuoles. These findings suggest that the permanent production of mutant PrP in the E200K gCJD cases overwhelms the ubiquitin-proteasome system and shifts the balance toward selectivemacroautophagy and/or to ubiquitinated inclusion body and aggresome formation as a cytoprotective effort to sequester the mutant protein.     

Agmatine enhances the anticonvulsant action of phenobarbital and valproate in the mouse maximal electroshock seizure model

Accumulating evidence indicates that agmatine (AGM—an endogenous neuromodulator/neurotransmitter in the brain) exerts the anticonvulsant action in various in vivo experiments. Therefore, the aim of this study was to assess the influence of AGM on the protective action of numerous conventional and newer antiepileptic drugs [carbamazepine (CBZ), lamotrigine (LTG), oxcarbazepine (OXC), phenobarbital (PB), phenytoin (PHT), topiramate (TPM) and valproate (VPA)] in the mouse maximal electroshock seizure (MES) model. Results indicate that AGM (up to 100 mg/kg, i.p., 45 min before the test) neither altered the threshold for electroconvulsions nor protected the animals against MES-induced seizures in mice. Moreover, AGM (100 mg/kg, i.p.) significantly enhanced the anticonvulsant effects of PB and VPA in the MES test by reducing their ED₅₀ values from 22.54 to 16.82 mg/kg (P < 0.01) for PB, and from 256.1 to 210.6 mg/kg (P < 0.05) for VPA, respectively. In contrast, AGM at 100 mg/kg (i.p.) had no significant effect on the antielectroshock action of the remaining drugs tested (CBZ, LTG, OXC, PHT, and TPM) in mice. Estimation of total brain PB and VPA concentrations revealed that the observed interactions between AGM and PB or VPA in the MES test were pharmacodynamic in nature because neither total brain PB, nor total brain VPA concentrations were altered after i.p. administration of AGM at 100 mg/kg. Moreover, none of the examined combinations of AGM (100 mg/kg) with CBZ, LTG, OXC, PB, PHT, TPM, and VPA (at their ED₅₀ values from the MES test) affected motor coordination in the chimney test, long-term memory in the passive avoidance task, and muscular strength in the grip-strength test in mice, indicating no acute adverse effects in animals. In conclusion, one can ascertain that the selective potentiation of the antielectroshock action of PB and VPA by AGM, lack of any pharmacokinetic interactions between drugs and no acute adverse effects, make the combinations of AGM with PB or VPA of pivotal importance for epileptic patients. It seems that modulation of AGM concentration in the brain may occur favorable in further clinical practice. The results of this study were presented in part at the “11th Congress of the European Federation of Neurological Societies” Brussels, Belgium, 25–28 August, 2007 [abstract in 2007, Eur J Neurol 14(Suppl 1):210].     

Activation of the mGlu7 receptor elicits antidepressant-like effects in mice

Rationale Broad evidence indicates that modulation of the glutamatergic system could be an efficient way to achieve antidepressant activity. Metabotropic glutamate receptor (mGlu receptor) ligands seem to be promising agents to treat several central nervous system disorders, including psychiatric ones. Objectives The aim of our study was to investigate potential antidepressant-like activity of the first, selective, and bio-available mGlu7 receptor agonist, AMN082 (N,N′-dibenzyhydryl-ethane-1,2-diamine dihydrochloride), in wild-type (WT) and mGlu7 receptor knock-out (KO) mice. Materials and methods The forced swim test (FST) and the tail suspension test (TST) in mice were used to assess antidepressant-like activity of AMN082. Results We found that AMN082, administered IP, induced a dose-dependent decrease in the immobility time of WT animals in the FST and TST, suggesting antidepressant-like potency of an mGlu7 receptor agonist. Moreover, AMN082 did not change the behaviour of mGlu7 receptor KO mice compared to WT littermates in the TST, while imipramine, used as a reference control, significantly reduced their immobility, indicating an mGlu7 receptor-dependent mechanism of the antidepressant-like activity of AMN082. However, at high doses, AMN082 significantly decreased spontaneous locomotor activity of both mGlu7 receptor KO mice and WT control animals, suggesting off-target activity of AMN082 resulting in hypo-locomotion. Conclusions These results strongly suggest that activation of the mGlu7 receptor elicits antidepressant-like effects.     

Computer tomography evaluation of the hip joint after Chiari osteotomy

Background. The goal of our study was to evaluate hip joints after Chiari osteotomy in computer tomography images, and to specify the field of coverage of the femoral head by the acetabulum. Material and methods. We evaluated treatment outcome in 27 patients who were treated at the Clinic of Orthopedics at the Poznan University of Medical Sciences during the period from 1965 to 1990. A Chiari osteotomy was performed on all patients for hip decentration or hip subluxation after developmental dysplasia. During the follow-up examination we evaluated the hips using CT scans taken at the greatest diameter of the femoral head and at the acetabulum level. Results. A wide area of femoral head coverage was most characteristic in the horizontal plane of the hip; the mean degree of femoral head coverage was 89.92%, which exceeded normal by 20%. On the computer tomograms taken at the greatest diameter of the femoral head the measurements were done with using the sector angles of Anada: anterior (ASA), posterior (PSA), and horizontal (HAS), as well as the anteversion angle (AA). The sector angles of Anada were within the normal range in most of these patients. Conclusions. When conducted correctly, Chiari osteotomy considerably improves femoral head coverage in the transverse plane.     

Laminin alpha1 chain reduces muscular dystrophy in laminin alpha2 chain deficient mice

Laminin (LN) alpha2 chain deficiency in humans and mice leads to severe forms of congenital muscular dystrophy (CMD). Here, we investigated whether LNalpha1 chain in mice can compensate for the absence of LNalpha2 chain and prevent the development of muscular dystrophy. We generated mice expressing a LNalpha1 chain transgene in skeletal muscle of LNalpha2 chain deficient mice. LNalpha1 is not normally expressed in muscle, but the transgenically produced LNalpha1 chain was incorporated into muscle basement membranes, and normalized the compensatory changes of expression of certain other laminin chains (alpha4, beta2). In 4-month-old mice, LNalpha1 chain could fully prevent the development of muscular dystrophy in several muscles, and partially in others. The LNalpha1 chain transgene not only reversed the appearance of histopathological features of the disease to a remarkable degree, but also greatly improved health and longevity of the mice. Correction of LNalpha2 chain deficiency by LNalpha1 chain may serve as a paradigm for gene therapy of CMD in patients.     

Physicians' views of interventions to reduce medical errors: does evidence of effectiveness matter?

PURPOSE: Despite widespread public attention and numerous ongoing patient safety initiatives, physicians are skeptical of the most commonly prescribed interventions to reduce medical errors. This study examined the association between the published evidence of effectiveness of interventions to reduce medical errors and physicians' ratings of the effectiveness of those interventions. It further assessed whether academic affiliation was associated with physicians' ratings of effectiveness. METHOD: The authors conducted a literature review seeking evidence of effectiveness of 13 interventions to reduce medical errors. A four-page questionnaire was sent to a random sample of 1,332 U.S. physicians in the spring of 2002. A total of 831 (62%) responded, providing ratings of the perceived effectiveness of these interventions to reduce medical errors. RESULTS: We identified published evidence of effectiveness for six of the 13 interventions. Physicians rated 34% of these and 29% of the interventions without published evidence as "very effective" (p < .01). Physicians with an academic affiliation and those in practice for more years were slightly more likely to rate interventions with published evidence as "very effective." CONCLUSIONS: Physicians' ratings of the effectiveness of interventions to reduce medical errors are only weakly associated with published evidence of effectiveness. More evidence, better dissemination strategies for existing evidence such as inclusion in medical school curriculum or recertification examinations, and a focus on removing barriers to interventions may be needed to engage physicians in moving patient safety interventions into medical practice.     

Estrogen regulates endothelial migration via plasminogen activator inhibitor (PAI-1)

Endothelial plasminogen activator inhibitor (PAI-1) controls vascular remodeling, angiogenesis and fibrinolysis. PAI-1 blood levels in women are related to estrogen. The aim of this study was to characterize the signaling pathways through which estrogen regulates PAI-1 in endothelial cells. Furthermore, we aimed to investigate whether PAI-1 is implicated in the control of endothelial migration by estrogen. Cultured human umbilical vein endothelial cells (HUVECs) and ovariectomized rats were used to test the effects of 17β-estradiol (E(2)) on PAI-1 expression and its role on endothelial migration. At physiological concentrations, E(2) increases the expression of PAI-1 in HUVEC within 6-12 h through activation of a signaling cascade initiated by estrogen receptor α and involving G proteins, phosphatidylinositol-3-OH kinase and Rho-associated kinase II. ROCK-II activation turns into an over-expression of c-Jun and c-Fos that is required for E(2)-induced expression of PAI-1. Estrogen-induced PAI-1 expression is implicated in HUVEC horizontal migration. PAI-1 regulation is found also in vivo, in female rats, where ovariectomy is associated with reduced PAI-1 expression, while estrogen replacement counteracts this change. In conclusion, E(2) increases PAI-1 synthesis in human endothelial cells and in rodent aorta through a G protein-initiated signaling that targets early-immediate gene expression. This regulatory pathway is implicated in endothelial cell migration. These findings describe new mechanisms of action of estrogens in the vessels, which may be important for vascular remodeling and hemostasis.     

Autophagy is increased in laminin α2 chain-deficient muscle and its inhibition improves muscle morphology in a mouse model of MDC1A

Congenital muscular dystrophy caused by laminin α2 chain deficiency (also known as MDC1A) is a severe and incapacitating disease, characterized by massive muscle wasting. The ubiquitin-proteasome system plays a major role in muscle wasting and we recently demonstrated that increased proteasomal activity is a feature of MDC1A. The autophagy-lysosome pathway is the other major system involved in degradation of proteins and organelles within the muscle cell. However, it remains to be determined if the autophagy-lysosome pathway is dysregulated in muscular dystrophies, including MDC1A. Using the dy(3K)/dy(3K) mouse model of laminin α2 chain deficiency and MDC1A patient muscle, we show here that expression of autophagy-related genes is upregulated in laminin α2 chain-deficient muscle. Moreover, we found that autophagy inhibition significantly improves the dystrophic dy(3K)/dy(3K) phenotype. In particular, we show that systemic injection of 3-methyladenine (3-MA) reduces muscle fibrosis, atrophy, apoptosis and increases muscle regeneration and muscle mass. Importantly, lifespan and locomotive behavior were also greatly improved. These findings indicate that enhanced autophagic activity is pathogenic and that autophagy inhibition holds a promising therapeutic potential in the treatment of MDC1A.