Thrombolysis and thrombectomy for acute ischaemic stroke

The likelihood of disability-free recovery after acute ischemic stroke is significantly improved by reperfusion either by intravenous thrombolytic drug treatment or with endovascular mechanical thrombectomy in selected cases. The use of intravenous thrombolysis is limited by the short treatment window and you need to assess individual balance of benefit and risk of symptomatic intracranial haemorrhage. Benefit is greater for shorter onset-to-reperfusion time intervals, requiring optimisation of pre-hospital and in-hospital pathways. Symptomatic haemorrhage is more likely with more severe strokes, but a greater proportion of patients are left free of disability than suffer a treatment-related haemorrhage at all levels of severity. Extracranial haemorrhage and orolingual angioedema are less common complications. Endovascular mechanical thrombectomy can be used in selected patients with imaging-proven large artery occlusion. Successful therapy depends on well-organised services that can deliver treatment within a short time window at centres with adequate expertise to perform the procedure

A requirement for PARP-1 for the assembly or stability of XRCC1 nuclear foci at sites of oxidative DNA damage

The molecular role of poly (ADP-ribose) polymerase-1 in DNA repair is unclear. Here, we show that the single-strand break repair protein XRCC1 is rapidly assembled into discrete nuclear foci after oxidative DNA damage at sites of poly (ADP-ribose) synthesis. Poly (ADP-ribose) synthesis peaks during a 10 min treatment with H2O2 and the appearance of XRCC1 foci peaks shortly afterwards. Both sites of poly (ADP-ribose) and XRCC1 foci decrease to background levels during subsequent incubation in drug-free medium, consistent with the rapidity of the single-strand break repair process. The formation of XRCC1 foci at sites of poly (ADP-ribose) was greatly reduced by mutation of the XRCC1 BRCT I domain that physically interacts with PARP-1. Moreover, we failed to detect XRCC1 foci in Adprt1¿/¿ MEFs after treatment with H2O2. These data demonstrate that PARP-1 is required for the assembly or stability of XRCC1 nuclear foci after oxidative DNA damage and suggest that the formation of these foci is mediated via interaction with poly (ADP-ribose). These results support a model in which the rapid activation of PARP-1 at sites of DNA strand breakage facilitates DNA repair by recruiting the molecular scaffold protein, XRCC1

APLF (C2orf13) is a novel human protein involved in the cellular response to chromosomal DNA strand breaks

Aprataxin and polynucleotide kinase (PNK) are DNA end processing factors that are recruited into the DNA single- and double-strand break repair machinery through phosphorylation-specific interactions with XRCC1 and XRCC4, respectively. These interactions are mediated through a divergent class of forkhead-associated (FHA) domain that binds to peptide sequences in XRCC1 and XRCC4 that are phosphorylated by casein kinase 2 (CK2). Here, we identify the product of the uncharacterized open reading frame C2orf13 as a novel member of this FHA domain family of proteins and we denote this protein APLF (aprataxin- and PNK-like factor). We show that APLF interacts with XRCC1 in vivo and in vitro in a manner that is stimulated by CK2. Yeast two-hybrid analyses suggest that APLF also interacts with the double-strand break repair proteins XRCC4 and XRCC5 (Ku86). We also show that endogenous and yellow fluorescent protein-tagged APLF accumulates at sites of H(2)O(2) or UVA laser-induced chromosomal DNA damage and that this is achieved through at least two mechanisms: one that requires the FHA domain-mediated interaction with XRCC1 and a second that is independent of XRCC1 but requires a novel type of zinc finger motif located at the C terminus of APLF. Finally, we demonstrate that APLF is phosphorylated in a DNA damage- and ATM-dependent manner and that the depletion of APLF from noncycling human SH-SY5Y neuroblastoma cells reduces rates of chromosomal DNA strand break repair following ionizing radiation. These data identify APLF as a novel component of the cellular response to DNA strand breaks in human cells

Excitation Control: Balancing PSD-95 Function at the Synapse

Excitability of individual neurons dictates the overall excitation in specific brain circuits. This process is thought to be regulated by molecules that regulate synapse number, morphology and strength. Neuronal excitation is also influenced by the amounts of neurotransmitter receptors and signaling molecules retained at particular synaptic sites. Recent studies revealed a key role for PSD-95, a scaffolding molecule enriched at glutamatergic synapses, in modulation of clustering of several neurotransmitter receptors, adhesion molecules, ion channels, cytoskeletal elements and signaling molecules at postsynaptic sites. In this review we will highlight mechanisms that control targeting of PSD-95 at the synapse, and discuss how this molecule influences the retention and clustering of diverse synaptic proteins to regulate synaptic structure and strength. We will also discuss how PSD-95 may maintain a balance between excitation and inhibition in the brain and how alterations in this balance may contribute to neuropsychiatric disorders

Prostatic Leiomyosarcoma: The Case for Combined Modality Therapy

Patient. A 65-year old man who had previously undergone surgery for benign prostatic hyperplasia presented with symptoms of recurrent bladder outflow obstruction. Cystoscopy revealed the presence of recurrent tissue

Regulation of the cardiomyocyte transcriptome vs translatome by endothelin-1 and insulin: translational regulation of 5' terminal oligopyrimidine tract (TOP) mRNAs by insulin

Background: Changes in cellular phenotype result from underlying changes in mRNA transcription and translation. Endothelin-1 stimulates cardiomyocyte hypertrophy with associated changes in mRNA/protein expression and an increase in the rate of protein synthesis. Insulin also increases the rate of translation but does not promote overt cardiomyocyte hypertrophy. One mechanism of translational regulation is through 5' terminal oligopyrimidine tracts (TOPs) that, in response to growth stimuli, promote mRNA recruitment to polysomes for increased translation. TOP mRNAs include those encoding ribosomal proteins, but the full panoply remains to be established. Here, we used microarrays to compare the effects of endothelin-1 and insulin on the global transcriptome of neonatal rat cardiomyocytes, and on mRNA recruitment to polysomes (i.e. the translatome). Results: Globally, endothelin-1 and insulin (1 h) promoted >1.5-fold significant (false discovery rate 1.25-fold significant changes in expression in total and/or polysomal RNA induced by endothelin-1 or insulin, respectively, of which ~35% of endothelin-1-responsive and ~56% of insulin-responsive transcripts were translationally regulated. Of mRNAs for established proteins recruited to polysomes in response to insulin, 49 were known TOP mRNAs with a further 15 probable/possible TOP mRNAs, but 49 had no identifiable TOP sequences or other consistent features in the 5' untranslated region. Conclusions: Endothelin-1, rather than insulin, substantially affects global transcript expression to promote cardiomyocyte hypertrophy. Effects on RNA recruitment to polysomes are subtle, with differential effects of endothelin-1 and insulin on specific transcripts. Furthermore, although insulin promotes recruitment of TOP mRNAs to cardiomyocyte polysomes, not all recruited mRNAs are TOP mRNAs

Regioselective chlorination of phenols in the presence of tetrahydrothiopyran derivatives

Four six-membered cyclic sulfides, namely tetrahydrothiopyran, 3-methyltetrahydrothiopyran, 4-methyltetrahydrothiopyran and 4,4-dimethyltetrahyrdrothiopyran have been used as moderators in chlorination reactions of various phenols with sulfuryl chloride in the presence of aluminum or ferric chloride. On chlorination of phenol, ortho-cresol and meta-cresol the para/ortho chlorination ratios and yields of the para-chloro isomers are higher than when no cyclic sulfide is used for all of the cyclic sulfides, but chlorination of meta-xylenol is less consistent, with some cyclic sulfides producing higher p/o ratios and others producing lower ratios than reactions having no sulfide present

Do clinicians overestimate the severity of intracerebral hemorrhage?

Background and Purpose— Intracerebral hemorrhage (ICH) has a poorer prognosis than acute ischemic stroke (AIS). However, clinician perception of prognosis may influence treatment decisions and adversely affect outcome. On acute CT, the conspicuity of ICH compared with AIS may lead clinicians to overestimate severity and influence prognostic evaluation. We investigated whether clinicians’ estimates of volume, severity, and prognosis from acute imaging differed between ICH and AIS. Methods— CT scans from participants with acute ICH or ischemic stroke were reviewed. Volume was calculated using the ABC/2 method and automated volumetric analysis via specialized imaging software. ICH cases were matched with AIS cases for lesion volume, based on acute (<6 hours) CT for ICH, and 24-hour CT for AIS. Blind to clinical information, clinicians estimated lesion volume to the nearest 5 mL, graded lesion severity from 1 (mild) to 5 (very severe), and estimated 30-day prognosis using the modified Rankin Scale. Results— We compared 33 ICH cases with 33 volume-matched AIS cases. Clinicians overestimated ICH volume and underestimated AIS volumes: mean differences (estimated−actual volume) were +8 mL (±30) for ICH and −8 mL (±27) for AIS (P<0.001). Observers rated ICH to be of greater severity and poorer prognosis compared with AIS cases: 109 of 265 (41%) ICH cases rated severity categories 4 or 5 compared with 36 of 257 (14%) AIS, P<0.001; estimated modified Rankin Scale of 0 to 2 in 125 of 265 (47%) ICH compared with 190 of 257 (74%) AIS, P<0.001. Results were unaffected by presence of intraventricular blood. Estimated severity and prognosis for ICH remained significantly worse compared with AIS after adjustment for estimated volumes. Conclusions— Clinicians overestimated ICH volume and severity compared with AIS of equivalent volume and also assigned significantly worse prognosis independent of volume estimates

TDP2 promotes repair of topoisomerase I-mediated DNA damage in the absence of TDP1

The abortive activity of topoisomerases can result in clastogenic and/or lethal DNA damage in which the topoisomerase is covalently linked to the 3'- or 5'-terminus of a DNA strand break. This type of DNA damage is implicated in chromosome translocations and neurological disease and underlies the clinical efficacy of an important class of anticancer topoisomerase 'poisons'. Tyrosyl DNA phosphodiesterase-1 protects cells from abortive topoisomerase I (Top1) activity by hydrolyzing the 3'-phosphotyrosyl bond that links Top1 to a DNA strand break and is currently the only known human enzyme that displays this activity in cells. Recently, we identified a second tyrosyl DNA phosphodiesterase (TDP2; aka TTRAP/EAPII) that possesses weak 3'-tyrosyl DNA phosphodiesterase (3'-TDP) activity, in vitro. Herein, we have examined whether TDP2 contributes to the repair of Top1-mediated DNA breaks by deleting Tdp1 and Tdp2 separately and together in murine and avian cells. We show that while deletion of Tdp1 in wild-type DT40 cells and mouse embryonic fibroblasts decreases DNA strand break repair rates and cellular survival in response to Top1-induced DNA damage, deletion of Tdp2 does not. However, deletion of both Tdp1 and Tdp2 reduces rates of DNA strand break repair and cell survival below that observed in Tdp1(-)(/)(-) cells, suggesting that Tdp2 contributes to cellular 3'-TDP activity in the absence of Tdp1. Consistent with this idea, over-expression of human TDP2 in Tdp1(-)(/)(-)/Tdp2(-)(/)(-)(/)(-) DT40 cells increases DNA strand break repair rates and cell survival above that observed in Tdp1(-)(/)(-) DT40 cells, suggesting that Tdp2 over-expression can partially complement the defect imposed by loss of Tdp1. Finally, mice lacking both Tdp1 and Tdp2 exhibit greater sensitivity to Top1 poisons than do mice lacking Tdp1 alone, further suggesting that Tdp2 contributes to the repair of Top1-mediated DNA damage in the absence of Tdp1. In contrast, we failed to detect a contribution for Tdp1 to repair Top2-mediated damage. Together, our data suggest that Tdp1 and Tdp2 fulfil overlapping roles following Top1-induced DNA damage, but not following Top2-induced DNA damage, in vivo

Preoperative neutrophil-lymphocyte ratio and outcome from coronary artery bypass grafting

Background: An elevated preoperative white blood cell count has been associated with a worse outcome after coronary artery bypass grafting (CABG). Leukocyte subtypes, and particularly the neutrophil-lymphocyte (N/L) ratio, may however, convey superior prognostic information. We hypothesized that the N/L ratio would predict the outcome of patients undergoing surgical revascularization. Methods: Baseline clinical details were obtained prospectively in 1938 patients undergoing CABG. The differential leukocyte was measured before surgery, and patients were followed-up 3.6 years later. The primary end point was all-cause mortality. Results: The preoperative N/L ratio was a powerful univariable predictor of mortality (hazard ratio [HR] 1.13 per unit, P 3.36). Conclusion: An elevated N/L ratio is associated with a poorer survival after CABG. This prognostic utility is independent of other recognized risk factors.Peer reviewedAuthor versio