Evaluating Osteoarthritis Management Programs: outcome domain recommendations from the OARSI Joint Effort Initiative.

OBJECTIVE: To develop sets of core and optional recommended domains for describing and evaluating Osteoarthritis Management Programs (OAMPs), with a focus on hip and knee Osteoarthritis (OA). DESIGN: We conducted a 3-round modified Delphi survey involving an international group of researchers, health professionals, health administrators and people with OA. In Round 1, participants ranked the importance of 75 outcome and descriptive domains in five categories: patient impacts, implementation outcomes, and characteristics of the OAMP and its participants and clinicians. Domains ranked as "important" or "essential" by ≥80% of participants were retained, and participants could suggest additional domains. In Round 2, participants rated their level of agreement that each domain was essential for evaluating OAMPs: 0 = strongly disagree to 10 = strongly agree. A domain was retained if ≥80% rated it ≥6. In Round 3, participants rated remaining domains using same scale as in Round 2; a domain was recommended as "core" if ≥80% of participants rated it ≥9 and as "optional" if ≥80% rated it ≥7. RESULTS: A total of 178 individuals from 26 countries participated; 85 completed all survey rounds. Only one domain, "ability to participate in daily activities", met criteria for a core domain; 25 domains met criteria for an optional recommendation: 8 Patient Impacts, 5 Implementation Outcomes, 5 Participant Characteristics, 3 OAMP Characteristics and 4 Clinician Characteristics. CONCLUSION: The ability of patients with OA to participate in daily activities should be evaluated in all OAMPs. Teams evaluating OAMPs should consider including domains from the optional recommended set, with representation from all five categories and based on stakeholder priorities in their local context.

Photonic crystal resonators for inverse-designed multi-dimensional optical interconnects.

We experimentally demonstrate a 400 Gbit/s optical communication link utilizing wavelength-division multiplexing and mode-division multiplexing for a total of 40 channels. This link utilizes a novel, to the best of our knowledge, 400 GHz frequency comb source based on a chip-scale photonic crystal resonator. Silicon-on-insulator photonic inverse-designed 4 × 4 mode-division multiplexer structures enable a fourfold increase in data capacity. We show less than -10 dBm of optical receiver power for error-free data transmission in 34 out of a total of 40 channels using a PRBS31 pattern.

Observation of rotational coherence in an excited state of CO.

The vacuum ultraviolet (VUV) radiation is generated in the strong-field-ionized CO molecules through 2+1 resonance excitation with two-color femtosecond laser pulses. When scanning the relative delay between two pump pulses, the rotational-resolved VUV radiations show periodic oscillations lasting as long as 500 ps. Fourier analysis reveals that these oscillations correspond to rotational beat frequencies of the A2Πi state of CO+, which is the result of multi-channel interference during the resonant excitation process. High resolution of Fourier transform spectra up to 0.067cm-1 allows us to obtain the fine energy levels of the A2Πi state. The theoretical calculation is in good agreement with the experimental observation. This work reveals the rotational coherence of the ionic excited state and shows the prospect of rotational coherence spectroscopy in measuring fine structures of molecular ions.

[Therapeutic effects of pars plana vitrectomy combined with internal limiting membrane peeling on high myopic foveoschisis].

Objective: To observe the clinical efficacy of vitrectomy combined with foveal-sparing circular internal limiting membrane peeling with the central fovea reserved in patients with high myopic foveoschisis. Methods: Case-control study. A total of 72 patients (86 eyes) with foveoschisis due to high myopia who underwent vitrectomy combined with internal limiting membrane peeling in Lishui Municipal Central Hospital of Zhejiang Province from June 2016 to May 2017 were enrolled, including 18 males (18 eyes) and 54 females (68 eyes), aged (50.5±8.9) years. The patients were randomly divided into the observation group (34 cases, 43 eyes) and the control group (38 cases, 43 eyes) using a random number table and random number residual grouping method. Vitrectomy was performed in all patients. In the control group, the limiting membrane in the macular area was removed during surgery. In the observation group, the foveal annular internal limiting membrane was preserved during surgery. In severe cases, cataract extraction was performed. Results: In the observation group, the mean central foveal thickness (CFT) on optical coherence tomography was (723.49±130.95) µm preoperatively and decreased to (286.33±210.73) µm postoperatively, and the difference had statistical significance (t=17.059, P=0.000). In 39 eyes with complete or partial healing of the foveal split, the best corrected visual acuity (BCVA) was (0.99±0.40) logMAR before the treatment and increased to 0.68±0.24 after the treatment, and the difference had statistical significance (t=7.585, P=0.000). In the control group, the mean CFT was (726.98±140.62) µm and (297.88±241.56.) µm before and after the treatment, respectively, and the difference had statistical significance (t=16.271, P=0.000). In 38 eyes with complete or partial healing of the foveal split, the BCVA increased from preoperative 1.04±0.47 to postoperative 0.69±0.21, and the difference had statistical significance (t=6.707, P=0.00). With the follow-up time as the efficacy determination time, there was no significant difference in BCVA (t=0.22, P=0.983) and CFT (t=0.236, P=0.814) between the observation group and the control group (P>0.05); there was significant difference in the incidence rate of macular holes (P=0.026). There was no statistically significant difference in the rate of complete macular morphology healing between the two groups (P=0.816). Conclusion: Vitrectomy combined with foveal-sparing circular internal limiting membrane peeling can effectively treat high myopic macular holes and reduce the formation of postoperative macular holes. (Chin J Ophthalmol, 2020, 56: 928-932).

Significance of TRPS1 in the development and clinicopathologic of hepatocellular carcinoma.

OBJECTIVE: The purpose of this paper was to explore roles and significance of transcriptional repressor GATA binding 1 (TRPS1) in the process of hepatocellular carcinoma (HCC) and clinicopathological parameters of HCC patients, respectively. PATIENTS AND METHODS: The expression of TRPS1 was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot. Chi-square test was used to investigate the association between TRPS1 and clinicopathological parameters of HCC patients. SiRNA was designed to suppress the expression of TRPS1. Moreover, transwell assay and cell cycle analysis were adopted to determine the invasion ability and proliferation ability of HCC cells. RESULTS: It was demonstrated that TRPS1 was abnormally over-expressed in HCC tissues and cells, and was closely associated with the vascular invasion, tumor size, and TNM stage of HCC patients. Besides, the results indicated that the inhibition of TRPS1 in HCC cells could impede the cell invasion ability and proliferation ability. CONCLUSIONS: TRPS1 plays a key role in the development of HCC and is closely associated with the clinicopathological parameters of HCC patients. Hence, it is proposed that TRPS1 may serve as a novel prognostic marker and a potential therapeutic target for HCC treatment.

Development of a core capability framework for qualified health professionals to optimise care for people with osteoarthritis: an OARSI initiative.

OBJECTIVE: Develop a generic trans-disciplinary, skills-based capability framework for health professionals providing care for people with OA. DESIGN: e-Delphi survey. An international inter-professional Delphi Panel (researchers; clinicians; consumer representatives) considered a draft framework (adapted from elsewhere) of 131 specific capabilities mapped to 14 broader capability areas across four domains (A: person-centred approaches; B: assessment, investigation and diagnosis; C: management, interventions and prevention; D: service and professional development). Over three rounds, the Panel rated their agreement (Likert or numerical rating scales) on whether each specific capability in Domains B and C was essential (core) for all health professionals when providing care for all people with OA. Those achieving consensus (≥80% of Panel) rating of ≥ seven out of ten (Round 3) were retained. Generic domains (A and D) were included in the final framework and amended based on Panel comments. RESULTS: 173 people from 31 countries, spanning 18 disciplines and including 26 consumer representatives, participated. The final framework comprised 70 specific capabilities across 13 broad areas i) communication; ii) person-centred care; iii) history-taking; iv) physical assessment; v) investigations and diagnosis; vi) interventions and care planning; vii) prevention and lifestyle interventions; viii) self-management and behaviour change; ix) rehabilitative interventions; x) pharmacotherapy; xi) surgical interventions; xii) referrals and collaborative working; and xiii) evidence-based practice and service development). CONCLUSION: Experts agree that health professionals require an array of skills in person-centred approaches; assessment, investigation and diagnosis; management, interventions and prevention; and service and professional development to provide optimal care for people with OA.

LncRNA UCA1 affects osteoblast proliferation and differentiation by regulating BMP-2 expression.

OBJECTIVE: The aim of this study was to detect the expression of long non-coding ribonucleic acid (lncRNA) urothelial carcinoma associated 1 (UCA1) in the plasma of patients with osteoporosis (OST), and to investigate its influences on the proliferation and differentiation of osteoblasts and its mechanism. PATIENTS AND METHODS: Plasma samples were collected from 52 OST patients treated in our hospital and 30 healthy subjects receiving a physical examination, respectively. The expression level of lncRNA UCA1 in OST patients and healthy subjects were detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Furthermore, osteoblast MC3T3-E1 cell lines with a stable knockout of UCA1 in mice were constructed using small-interfering RNA (siRNA). The influence of UCA1 knockout on the proliferation of osteoblasts was detected using cell counting kit-8 (CCK-8) assay. Meanwhile, the proportion of EdU-positive cells in osteoblasts of the control group and UCA1 knockout group was detected using EdU staining. Moreover, the messenger RNA (mRNA) levels of differentiation-related genes, including Runt-related transcription factor 2 (Runx2), Collagen1α1, osteoclast (OC), osteoprotegerin (OPG), osteopontin (OPN) and Osterix (OSX), were detected via RT-PCR. The protein expression level of Runx2 was detected via Western blotting. In addition, osteoblasts were cultured with a bone-derived medium for 14 d. Then, the differentiation status was detected via alizarin red staining and alkaline phosphatase staining. Finally, the expression of bone morphogenetic protein-2 (BMP-2)/(Smad1/5/8) signaling pathway was analyzed using Western blotting. RESULTS: The expression of plasma lncRNA UCA1 was significantly increased in OST patients (p<0.05). Cell experiments revealed that UCA1 siRNA intervention could significantly promote the proliferation and differentiation of osteoblast MC3T3-E1 cell lines. In addition, Western blotting showed that the pro-apoptotic effect of UCA1 might be mediated by the BMP-2/(Smad1/5/8) signaling pathway in osteoblasts. CONCLUSIONS: Inhibiting lncRNA UCA1 can promote the proliferation and differentiation of osteoblasts by activating the BMP-2/(Smad1/5/8) signaling pathway in osteoblasts. Therefore, UCA1 is expected to be a new therapeutic target for OST.

Chinese military medical teams in the Ebola outbreak of Sierra Leone.

The 2014-2015 Ebola virus disease (EVD) epidemic in West Africa was the largest in history. The three most affected countries, Guinea, Liberia and Sierra Leone, have faced enormous challenges in controlling transmission and providing clinical care for patients with EVD. The Chinese government, in response to the requests of the WHO and the governments of the affected countries, responded rapidly by deploying Chinese military medical teams (CMMTs) to the areas struck by the deadly epidemic. A total of three CMMTs, comprising 115 military medical professionals, were rotationally deployed to Freetown, Sierra Leone to assist with infection prevention and control, clinical care and health promotion and training. Between 1 October 2014 and 22 March 2015, the CMMTs in Sierra Leone admitted and treated a total of 773 suspected and 285 confirmed EVD cases. Among the 285 confirmed cases, 146 (51.2%) patients survived after treatment. In addition, the CMMTs maintained the record of zero infections among healthcare workers and zero cross-infections between quarantined patients. In this manuscript, we aim to give an overview of the mission, and share our best practices experience on predeployment preparedness, EVD holding and treatment centre building and EVD case management.

Superradiance for Atoms Trapped along a Photonic Crystal Waveguide.

We report observations of superradiance for atoms trapped in the near field of a photonic crystal waveguide (PCW). By fabricating the PCW with a band edge near the D(1) transition of atomic cesium, strong interaction is achieved between trapped atoms and guided-mode photons. Following short-pulse excitation, we record the decay of guided-mode emission and find a superradiant emission rate scaling as Γ̅(SR)∝N̅Γ(1D) for average atom number 0.19≲N̅≲2.6 atoms, where Γ(1D)/Γ'=1.0±0.1 is the peak single-atom radiative decay rate into the PCW guided mode, and Γ' is the radiative decay rate into all the other channels. These advances provide new tools for investigations of photon-mediated atom-atom interactions in the many-body regime.

Atom-light interactions in photonic crystals.

The integration of nanophotonics and atomic physics has been a long-sought goal that would open new frontiers for optical physics, including novel quantum transport and many-body phenomena with photon-mediated atomic interactions. Reaching this goal requires surmounting diverse challenges in nanofabrication and atomic manipulation. Here we report the development of a novel integrated optical circuit with a photonic crystal capable of both localizing and interfacing atoms with guided photons. Optical bands of a photonic crystal waveguide are aligned with selected atomic transitions. From reflection spectra measured with average atom number N=1.1+/-0.4, we infer that atoms are localized within the waveguide by optical dipole forces. The fraction of single-atom radiative decay into the waveguide is Γ1D/Γ'≃(0.32±0.08), where Γ1D is the rate of emission into the guided mode and Γ' is the decay rate into all other channels. Γ1D/Γ' is unprecedented in all current atom-photon interfaces.

The TRPC channel blocker SKF 96365 inhibits glioblastoma cell growth by enhancing reverse mode of the Na(+) /Ca(2+) exchanger and increasing intracellular Ca(2+).

BACKGROUND AND PURPOSE: SKF 96365 is well known for its suppressing effect on human glioblastoma growth by inhibiting pre-activated transient receptor potential canonical (TRPC) channels and Ca(2+) influx. The effect of SKF 96363 on glioblastoma cells, however, may be multifaceted and this possibility has been largely ignored. EXPERIMENTAL APPROACH: The effects of SKF 96365 on cell cycle and cell viability of cultured human glioblastoma cells were characterized. Western blot, Ca(2+) imaging and patch clamp recordings were used to delineate cell death mechanisms. siRNA gene knockdown provided additional evidence. KEY RESULTS: SKF 96365 repressed glioblastoma cell growth via increasing intracellular Ca(2+) ([Ca(2+) ]i ) irrespective of whether TRPC channels were blocked or not. The effect of SKF 96365 primarily resulted from enhanced reverse operation of the Na(+) /Ca(2+) exchanger (NCX) with an EC50 of 9.79 µM. SKF 96365 arrested the glioblastoma cells in the S and G2 phases and activated p38-MAPK and JNK, which were all prevented by the Ca(2+) chelator BAPTA-AM or EGTA. The expression of NCX in glioblastoma cells was significantly higher than in normal human astrocytes. Knockdown of the NCX1 isoforms diminished the effect of SKF 96365 on glioblastoma cells. CONCLUSIONS AND IMPLICATIONS: At the same concentration, SKF 96365 blocks TRPC channels and enhances the reverse mode of the NCX causing [Ca(2+) ]i accumulation and cytotoxicity. This finding suggests an alternative pharmacological mechanism of SKF 96365. It also indicates that modulation of the NCX is an effective method to disrupt Ca(2+) homeostasis and suppress human glioblastoma cells.

Acute and delayed protective effects of pharmacologically induced hypothermia in an intracerebral hemorrhage stroke model of mice.

Hemorrhagic stroke, including intracerebral hemorrhage (ICH), is a devastating subtype of stroke; yet, effective clinical treatment is very limited. Accumulating evidence has shown that mild to moderate hypothermia is a promising intervention for ischemic stroke and ICH. Current physical cooling methods, however, are less efficient and often impractical for acute ICH patients. The present investigation tested pharmacologically induced hypothermia (PIH) using the second-generation neurotensin receptor (NTR) agonist HPI-201 (formerly known as ABS-201) in an adult mouse model with ICH. Acute or delayed administrations of HPI-201 (2mg/kg bolus injection followed by 2 injections of 1mg/kg, i.p.) were initiated at 1 or 24h after ICH. HPI-201 induced mild hypothermia within 30 min and body and brain temperatures were maintained at 32.7 ± 0.4°C for at least 6h without causing observable shivering. With the 1-h delayed treatment, HPI-201-induced PIH significantly reduced ICH-induced cell death and brain edema compared to saline-treated ICH animals. When HPI-201-induced hypothermia was initiated 24h after the onset of ICH, it still significantly attenuated brain edema, cell death and blood-brain barrier breakdown. HPI-201 significantly decreased the expression of matrix metallopeptidase-9 (MMP-9), reduced caspase-3 activation, and increased Bcl-2 expression in the ICH brain. Moreover, ICH mice received 1-h delayed HPI-201 treatment performed significantly better in the neurological behavior test 48 h after ICH. All together, these data suggest that systemic injection of HPI-201 is an effective hypothermic strategy that protects the brain from ICH injury with a wide therapeutic window. The protective effect of this PIH therapy is partially mediated through the alleviation of apoptosis and neurovascular damage. We suggest that pharmacological hypothermia using the newly developed neurotensin analogs is a promising therapeutic treatment for ICH.

The regulatory role of NF-κB in autophagy-like cell death after focal cerebral ischemia in mice.

Autophagy may contribute to ischemia-induced cell death in the brain, but the regulation of autophagic cell death is largely unknown. Nuclear factor kappa B (NF-κB) is a regulator of apoptosis in cerebral ischemia. We examined the hypothesis that autophagy-like cell death could contribute to ischemia-induced brain damage and the process was regulated by NF-κB. In adult wild-type (WT) and NF-κB p50 knockout (p50(-/-)) mice, focal ischemia in the barrel cortex was induced by ligation of distal branches of the middle cerebral artery. Twelve to 24h later, autophagic activity increased as indicated by enhanced expression of Beclin-1 and LC3 in the ischemic core and/or penumbra regions. This increased autophagy contributed to cell injury, evidenced by terminal deoxynucleotidyltransferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) co-staining and a protective effect achieved by the autophagy inhibitor 3-methyladenine. The number of Beclin-1/TUNEL-positive cells was significantly more in p50(-/-) mice than in WT mice. Neuronal and vascular cell death, as determined by TUNEL-positive cells co-staining with NeuN or Collagen IV, was more abundant in p50(-/-) mice. Immunostaining of the endothelial cell tight junction marker occludin revealed more damage to the blood-brain barrier in p50(-/-) mice. Western blotting of the peri-infarct tissue showed a reduction of Akt-the mammalian target of rapamycin (mTOR) signaling in p50(-/-) mice after ischemia. These findings provide the first evidence that cerebral ischemia induced autophagy-like injury is regulated by the NF-κB pathway, which may suggest potential treatments for ischemic stroke.

Targeted drug regulation on methylation of p53-BAX mitochondrial apoptosis pathway affects the growth of cholangiocarcinoma cells.

OBJECTIVE: To study the mechanism of 5-aza-2-deoxycytidine (DAC; a methylation inhibitor) on growth of the human cholangiocarcinoma QBC939 cell line. METHODS: A colourimetric assay was used to detect growth of QBC939 cells treated with DAC (0.1-100 µmol/l) over 24 h, 48 h and 72 h. Cell morphology was observed by transmission electron microscopy (TEM). The cell cycle and apoptosis were analysed by flow cytometry. Hypermethylation of the promoters of the p53-BAX mitochondrial apoptosis genes cyclin-dependent kinase inhibitor 2A (CDKN2A), death-associated protein kinase 1 (DAPK1) and PYD and CARD domain containing (PYCARD) was detected by methylation-specific polymerase chain reaction, with and without DAC treatment. RESULTS: DAC inhibited QBC939 cell growth with a half maximal inhibitory concentration of 5 µmol/l at 72 h. After DAC treatment, apoptosis was observed by TEM. Flow cytometric analysis of propidium iodide-positive cells demonstrated increased apoptosis of DAC-treated QBC939 cells (43.04%) compared with untreated cells (4.31%). DAC treatment resulted in demethylation of the gene promoters of CDKN2A and DAPK1 in QBC939 cells. CONCLUSIONS: DAC induces apoptosis of QBC939 cells by reactivation of hypermethylated p53-BAX mitchondrial apoptosis genes in cholangiocarcinoma cells.

Novel role of KCNQ2/3 channels in regulating neuronal cell viability.

Overactivation of certain K(+) channels can mediate excessive K(+) efflux and intracellular K(+) depletion, which are early ionic events in apoptotic cascade. The present investigation examined a possible role of the KCNQ2/3 channel or M-channel (also named Kv7.2/7.3 channels) in the pro-apoptotic process. Whole-cell recordings detected much larger M-currents (212 ± 31 pA or 10.5 ± 1.5 pA/pF) in cultured hippocampal neurons than that in cultured cortical neurons (47 ± 21 pA or 2.4 ± 0.8 pA/pF). KCNQ2/3 channel openers N-ethylmaleimide (NEM) and flupirtine caused dose-dependent K(+) efflux, intracellular K(+) depletion, and cell death in hippocampal cultures, whereas little cell death was induced by NEM in cortical cultures. The NEM-induced cell death was antagonized by co-applied KCNQ channel inhibitor XE991 (10 µM), or by elevated extracellular K(+) concentration. Supporting a mediating role of KCNQ2/3 channels in apoptosis, expression of KCNQ2 or KCNQ2/3 channels in Chinese hamster ovary (CHO) cells initiated caspase-3 activation. Consistently, application of NEM (20 µM, 8 h) in hippocampal cultures similarly caused caspase-3 activation assessed by immunocytochemical staining and western blotting. NEM increased the expression of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), induced mitochondria membrane depolarization, cytochrome c release, formation of apoptosome complex, and apoptosis-inducing factor (AIF) translocation into nuclear. All these events were attenuated by blocking KCNQ2/3 channels. These findings provide novel evidence that KCNQ2/3 channels could be an important regulator in neuronal apoptosis.

Erythropoietin attenuates intracerebral hemorrhage by diminishing matrix metalloproteinases and maintaining blood-brain barrier integrity in mice.

The protective mechanism of recombinant human erythropoietin (rhEPO) on blood-brain barrier (BBB) after brain injury is associated with the attenuation of neuro-inflammation. We hypothesize that rhEPO treatment after intracerebral hemorrhage (ICH) modulates matrix metalloproteinase (MMP) activity, maintains BBB integrity, and reduces BBB breakdown-associated inflammation. Adult male 129S2/sv mice were subjected to autologous whole blood-induced ICH. rhEPO or saline was administered intraperitoneally immediately after surgery and for 3 more days until day of sacrifice. BBB permeability was measured by Evans blue leakage, and edema was assessed by brain water content. Immunofluorescence and Western blotting were performed to detect expression of tight junction marker occludin, type IV collagen, MMPs, tissue inhibitor of metalloproteinase (TIMP), and glial fibrillary acidic protein, rhEPO prevented Evans blue leakage, reduced brain edema, and preserved expression of occludin and collagen IV. rhEPO treatment decreased MMP-2 expression, increased TIMP-2 expression, and reduced the number of reactive astrocytes in the brain compared to saline control. We conclude that rhEPO reduces MMP activity, BBB disruption, and the glial cell inflammatory reaction 3 days after ICH. Our study provides additional evidence for the mechanism of rhEPO's neurovascular protective effects and a potential clinical application in the treatment of ICH.

Age-related neural degeneration in nuclear-factor kappaB p50 knockout mice.

Nuclear factor-kappaB is a transcription factor that regulates a variety of genes involved not only with immune and inflammatory responses, but also in cell survival. Nuclear-factor kappaB in the CNS is an area of current research interest; however, its role in age-related neural degeneration is obscure. The present study examines developmental degeneration changes in wild type and nuclear factor-kappaB p50 subunit knockout mice (p50-/-) using various morphological methodologies. P50-/- mice appeared normal at birth. At 6 and 10 months old, the body weight of p50-/- mice was significantly less than that of wild type mice and they started to die from aging. Consistently, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling positive cells in the cortex were significantly more in p50-/- mice than that in wild type mice, and neuronal cells in the cortex, hippocampus and caudate nucleus-putamen decreased in p50-/- mice. Fewer myelinated axons of the optic nerve were found in p50-/- mice than in wild type mice at 6 months. In p50-/- mice, morphological examinations showed: 1) aging and degenerative changes in the cortex and hippocampus including increased lipofuscin granules in neural cytoplasm, 2) abnormal capillaries, 3) dark and watery alterations and organelle accumulations, 4) apoptotic glia cells, and 5) terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling and caspase-3 positive neurons. These results suggest that nuclear-factor kappaB may play an important role in neurovascular development, cell survival, and the aging process in the CNS. This new evidence linking nuclear-factor kappaB to myelination and aging may be of considerable importance for several areas of basic and clinical neuroscience.

Role of K(+) efflux in apoptosis induced by AMPA and kainate in mouse cortical neurons.

Activation of ionotropic glutamate receptors can induce neuronal apoptosis in vitro and in vivo. We showed previously that activation of the N-methyl-D-aspartic acid (NMDA) subtype of glutamate receptors in a low Ca(2+) and low Na(+) condition induced apoptotic neuronal death, and that the K(+) efflux via NMDA receptor channels was likely a key event in NMDA-induced apoptosis. Since non-NMDA receptors, alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) and kainate receptors, are also permeable to K(+), we tested the hypothesis that stimulating K(+) efflux via non-NMDA receptor channels could induce apoptosis in cultured cortical neurons. Using a Ca(2+)-free and Na(+)-free external solution, application of kainate revealed outward membrane currents carried by K(+) efflux. In a low Ca(2+)/low Na(+) medium, a 5-h exposure to 50-500 microM AMPA in the presence of the NMDA receptor antagonist MK801 induced dose-dependent neuronal death 24 h after the onset of the insult, accompanied by intracellular K(+) reduction and caspase-3 activation. The AMPA-induced cell death was attenuated by the caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) and by the protein synthesis inhibitor cycloheximide. Reducing K(+) efflux by raising extracellular K(+) concentration from 5 to 25 mM attenuated AMPA-triggered cell death, the Ca(2+) channel antagonist nifedipine showed no effect on the AMPA toxicity. Kainate induced similar neuronal death sensitive to attenuation by Z-VAD-FMK or elevated extracellular K(+).We suggest that the non-NMDA receptor-mediated K(+) efflux may participate in apoptotic process and that blocking excessive K(+) efflux mediated by NMDA and non-NMDA receptors may selectively prevent neuronal apoptosis under certain pathological conditions.

Zinc induces a Src family kinase-mediated up-regulation of NMDA receptor activity and excitotoxicity.

Zinc is coreleased with glutamate from excitatory nerve terminals throughout the central nervous system and acutely inhibits N-methyl-d-aspartate (NMDA) receptor activation. Here we report that cultured murine cortical neurons briefly exposed to sublethal concentrations of zinc developed increased intracellular free Na(+), phosphorylation of Src kinase at tyrosine 220, and tyrosine phosphorylation of NMDA receptor 2A/2B subunits, in a fashion sensitive to the Src family kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine, PP2. Functionally, this zinc exposure produced a delayed increase in NMDA receptor current in perforated patch but not conventional whole-cell recordings, as well as an increase in NMDA receptor-mediated cell death. These observations suggest that the effect of synaptically released zinc on neuronal NMDA receptors may be biphasic: acute block, followed by Src family kinase-mediated up-regulation of NMDA receptor activity and cytotoxicity.