Protecting healthcare workers and patients during the COVID-19 pandemic: a comparison of baseline and follow-up infection prevention and control needs in Nigerian military healthcare facilities delivering HIV services.

BACKGROUND: Protecting the HIV health workforce is critical for continuity of services for people living with HIV, particularly during a pandemic. Early in the COVID-19 pandemic, the Nigerian Ministry of Defence, in partnership with the US Military HIV Research Program, took steps to improve infection prevention and control (IPC) practices among staff working in select PEPFAR-supported Nigerian military health facilities. METHODS: We identified a set of IPC activities a priori for implementation at four Nigerian military hospitals in HIV and related departments in early 2021, including continuous medical masking, physical distancing, placement of additional hand washing stations and hand sanitizers throughout facilities, and training. We fine-tuned planned intervention activities through a baseline needs assessment conducted in December 2020 that covered eight IPC components: 'IPC program structure, funding and leadership engagement'; 'IPC policies, guidelines and standard operating procedures (SOPs)'; 'infrastructure'; 'triage and screening'; 'training, knowledge and practice'; 'personal protective equipment (PPE) materials, availability and adequacy'; 'biosafety and waste management'; and 'monitoring and remediation' prior to implementation. Baseline results were compared with those of a follow up assessment administered in August 2021, following intervention implementation. RESULTS: IPC readiness remained high at both baseline and follow-up assessments for 'IPC guidelines, policies, and SOPs' (96.7%). The components 'infrastructure' and 'monitoring and remediation', which needed improvement at baseline, saw modest improvements at follow-up, by 2% and 7.5%, respectively. At follow-up, declines from high scoring at baseline were seen in 'IPC program structure, funding and leadership engagement', 'training, knowledge and practice', and 'biosafety and waste management'. 'PPE materials availability and adequacy' improved to 88.9% at follow-up. Although unidirectional client flow was newly implemented, the score for 'triage and screening' did not change from baseline to follow-up (73%). CONCLUSION: Variability in IPC component readiness and across facilities highlights the importance of building resilience and employing a quality improvement approach to IPC that includes regular monitoring, re-assessment and re-training at set intervals. Results can be used to encourage solutions-oriented dialogue between staff and leadership, determine needs and implement action plans to protect staff and people with HIV.

Impact of various monomers on release of losartan potassium from guar gum based polymeric network.

Present study was carried out to analyze the impact of three different monomers on release of losartan potassium from graft polymeric network prepared through free radical polymerization. N, N-methylene bis acrylamide was used as crosslinker and potassium persulfate as initiator. Losartan potassium as used as model drug because, it has very small plasma half-life and wide range of applications as an effective and efficient ARB (Angiotensin II Receptor Blockers) causing lower incidence of side - effects. Influence of three different monomers on swelling and in vitro drug release of the delivery system was evaluated at pH 1.2 and 7.4. The polymeric networks were characterized by Fourier transform infrared spectroscopy, Thermogravimetric analysis and Scanning electron microscopy. Polymeric network prepared with acrylic acid and methacrylic acid showed pH responsive behavior and while acrylamide based nexus exhibited pH independent style in swelling and drug release. However, among all the formulations, maximum swelling ratio (25.86) and optimal prolonged drug release (82.92%) was observed for GG-co-AA (M2) polymeric network at intestinal pH 7.4. The results indicated that GG-co-AA polymeric network could be an impending pH-sensitive drug delivery system for Losartan potassium. (M2) designated as formulation code with varying acrylic acid contents.

Development and evaluation of Artemisia vulgaris mucilage based polymeric network for controlled drug delivery.

The present study was conducted to fabricate and compare pH-sensitive polymeric networks of Artemisia vulgaris- Methacrylic acid using free radical polymerization conventional method and microwave-assisted method. Potassium persulphate and N' N'- Methylene bisacrylamide were employed as an initiator-crosslinker system. Swelling studies were performed at pH 1.2, 4.5, 6.8 and 7.4. Concentrations of polymer and monomer along with radiation dose were optimized as a function of swelling. Porosity and gel fraction were calculated for all samples. FTIR study confirmed the formation of cross-linked networks. Results of SEM indicated that the microwave irradiated polymeric network had a more porous structure. DSC and XRD study indicated the entrapment of drug inside the polymeric networks in amorphous form. In comparison to the conventional method, the polymeric network prepared by the microwave-assisted method exhibited high swelling ratios, porosity, thermal stability and drug release. These results signify microwave radiations as an effective alternative to the conventional heating method.

The effectiveness of extracorporeal shockwave therapy for frozen shoulder in patients with diabetes: randomized control trial.

[Purpose] This study examined the effectiveness of extracorporeal shock wave therapy versus ultrasound therapy, combined with the mobilization and therapeutic exercise in both groups, in participants with diabetic frozen shoulder. [Participants and Methods] Twenty participants with diabetic frozen shoulder were divided into an experimental group who received extracorporeal shock wave therapy, mobilization and exercises (n=10, Mean: 43.70) and the control group who received ultrasound, mobilization and exercises (n=10 Mean: 45.50). The clinical outcomes, i.e., a) pain b) active range of motions of the shoulder, c) disability scores by Disabilities of the Arm, Shoulder and Hand scale and d) global rating of change was measured weekly for four weeks. [Results] Significant improvements in pain, all active range of motions and disability scores were observed at the end of the 4th week in both groups. Additionally, the experimental group benefitted significant pain reduction (median difference: 7 in experimental versus 6 in control group), reduced number of therapy sessions and thus the costs of treatment compared to the control group. [Conclusion] Extracorporeal shock wave therapy significantly reduced pain in people with diabetic frozen shoulder with a reduction of treatment cost compared to the control group.

DEVELOPMENT AND CHARACTERIZATION OF SMART DRUG DELIVERY SYSTEM.

Present work concerned with development and evaluation of an innovative drug carrier, as smart drug delivery system for highly acid labile drug. Free radical polymerization technique was employed to develop pH sensitive drug delivery system by using carboxymethyl cellulose (polymer), methacrylic acid (monomer), potassium persulfate (initiator) and N,N methylene bisacrylamide (crosslinker). Prepared crosslinked polymer was characterized by swelling analysis at acidic and basic pH to evaluate pH responsive swelling, instrumental analysis (SEM, FIIR and thermal analysis) and pH responsive release of model drug rabeprazole sodium. Characterization of smart drug delivery concluded that pH responsive swelling and drug release parameters were directly related with methacrylic acid concentration in the crosslinked polymer. It was observed that by raising methacrylic acid contents swelling at basic pH enhanced and crosslinker contents increment reduce swelling. Among nine formulations with varying formulation contents, CMA2 exhibited more pH sensitive swelling and cumulative drug release at alkaline pH. Results of investigation recommended that CMA2 can be a best crosslinked polymer as smart drug carrier.

Physicochemical characterization and evaluation of suspending properties of arabinoxylan from Ispaghula (Plantago ovata) husk.

The purpose of this study is to evaluate the use of arabinoxylan as potential suspending agent, an effective alternative to commercially used excipients for the preparation of pharmaceutical suspensions. Alkali extraction was done to separate arabinoxylan from ispaghula (Plantago ovata) seed husk by alkali extraction its physicochemical characterization was done and the suspending properties of arabinoxylan isolated were evaluated comparatively with those of bentonite at different concentration ranges of 0.125,0.25,0.5 and 1% in Zinc oxide suspension. The parameters employed for evaluation were sedimentation volume, degree of flocculation, flow rate, density, pH, redispersibility, microbiological evaluation and particle size analysis. Physicochemical characterization of arabinoxylan indicates its suitability as excipient as it has fair flow properties, low moisture content and almost neutral pH. Arabinoxylan at low conc. 0.125% showed sedimentation volume comparable to commercially used suspending agents such as bentonite 1% while suspensions containing higher concentrations such as 0.25% (sedimentation volume 92%), 0.5% (sedimentation volume 94%) and 1% conc. (sedimentation volume 98%) of arabinoxylan remained almost completely suspended during study period of 7 days. Formulations containing 0.125% and 0.25% arabinoxylan as suspending agents are easily redispersible as compared to bentonite containing formulation while formulation containing 0.5% arabinoxylan are moderately redispersible while formulation containing 1% suspending agent gel upon storage and was not redispersible. Furthermore arabinoxylan produces stable, highly flocculated suspension, which fulfilled microbiological, and particle size specifications, however the formulations containing higher arabinoxylan 1% concentration gel upon storage. So it is concluded that arabinoxylan could be used as effective suspending agent at low concentrations in Zinc oxide suspension.

Pharmacokinetic studies of metformin and glibenclamide in normal human volunteers.

The study was aimed to evaluate various pharmacokinetic parameters of a commercially available fixed dose combination of oral antidiabetics (Metformin/Glibenclamide 500/5mg tablets) in plasma sample of normal healthy adult male volunteers by applying an accurate, selective, and reproducible HPLC-UV analytical method for quantification of Metformin HCL and Glibenclamide simultaneously in a single chromatographic run. Previously no HPLC-UV analytical method for simultaneous estimation of Metformin/Glibenclamide has been reported in Pakistan. The human plasma samples were evaluated by using an isocratic High Performance Liquid Chromatography (HPLC) system of Sykam consisted of a pump with a column of Thermo Electron Corporation USA (ODS hypersil C18 4.6 mm x 250 mm), a UV-detector with data processing Clarity software. The mobile phase of 0.040M Potassium dihydrogen phosphate containing 0.25mL/L triethylamine at pH 3.5 (adjusted with 1:1 phosphoric acid) and acetonitrile (465: 535v/v) was delivered with injection volume of 100µL at flow rate of 1 mL/min at 25°C temperature. The detection was performed at λmax230 nm. By applying this method, important pharmacokinetic parameters Cmax, Tmax, AUCo-oo, AUMCo-oo, t1/2, Ke, MRT, Vdand CIT are calculated. Maximum plasma concentrations Cmax was 131.856±8.050ng/ml for Glibenclamide (Mean ± SEM) and 511.106±12.675 ng/ml for Metformin HCl (Mean ±SEM).

Synthesis and evaluation of chitosan based controlled release nanoparticles for the delivery of ticagrelor.

The aim of this contemporary work was to formulate a controlled release mucoadhesive nanoparticle formulation for enhancing the oral bioavailability of Ticagrelor (TG), a BCS class IV drug, having low oral bioavailability of about 36%. The nanoparticles can act as efficient carriers for hydrophobic drugs, due to having high surface area and hence can improve their aqueous solubility due to their hydrophilic nature. The nanoparticles (NPs) of TG were formulated using chitosan (CH) as polymer and sodium tripolyphosphate (TPP) as cross-linker, by ionic gelation technique with varying concentrations of polymer with respect to TG and TPP. Characterization of prepared nanoparticles was carried out to assess zeta potential, size, shape, entrapment efficiency (EE) and loading capacity (LC), using zeta sizer, surface morphology and chemical compatibility analysis. Drug release was observed using UV-Spectrophotometer. By increasing concentration of CH the desired size of particles (106.9 nm), zeta potential (22.6 mv) and poly dispersity index (0.364) was achieved. In vitro profiles showed a controlled and prolonged release of TG in both lower pH-1.2 and neutral pH-7.4 mediums, with effective protection of entrapped TG in simulated gastric conditions. X-ray diffraction patterns (XRD) showed the crystalline nature of formed NPs. Hence, this effort showed that hydrophobic drugs can be effectively encapsulated in nanoparticulate systems to enhance their solubility and stability, ultimately improving their bioavailability and effectiveness with better patient compliance by reducing dosing frequencies as well.

Minnesota One Health Antibiotic Stewardship Collaborative: A Reproducible Approach to Facilitate Antimicrobial Stewardship Progress.

The Minnesota One Health Antibiotic Stewardship Collaborative (MOHASC) was launched in 2016 with the mission of providing a collaborative environment to promote judicious antibiotic use and antibiotic stewardship (AS) and to reduce the impact of antibiotic-resistant pathogens of human, animal, and environmental health importance. MOHASC goals include improving AS programs in healthcare and veterinary medicine, advancing understanding of environmental impacts of antibiotic use, and promoting a One Health (OH) approach to AS. These goals are accomplished through quarterly meetings of 4 work groups, field trips, collaborative research, an annual member meeting, and public education events. This novel OH approach has strengthened multidisciplinary relationships within Minnesota and led to procurement of funding to enhance AS initiatives beyond the Collaborative. This perspective serves as a blueprint for other jurisdictions, and we advocate for use of this reproducible OH strategy to facilitate broad AS goals.

Formulation and Evaluation of Linum usitatissimum Mucilage-Based Nanoparticles for Effective Delivery of Ezetimibe.

INTRODUCTION: The aim of current study was to prepare Linum usitatissimum mucilage (LUM) based nanoparticles, capable of encapsulating hydrophobic drug ezetimibe as nanocarriers. METHODS: Solvent evaporation and nanoprecipitation techniques were used to develop nanoparticles by encapsulating ezetimibe in the articulated matrix of polysaccharide fractions. Developed nanoparticles were characterized to determine the particle size, zeta potential, polydispersibility index (PDI), and entrapment efficiency (EE). Morphology and physicochemical characterization were carried out through SEM, FTIR, PXRD and thermal analysis. Saturation solubility and in vitro release studies were also performed. Safety assessment of ezetimibe loaded nanoparticles was evaluated via oral acute toxicity study. RESULTS: The mean particle size, zeta potential, PDI and EE for emulsion solvent evaporation were 683.6 nm, -28.3 mV, 0.39, 63.7% and for nanoprecipitation were 637.7 nm, 0.07, -27.1 mV and 80%, respectively. Thermal analysis confirmed enhanced thermal stability, whereas PXRD confirmed amorphous nature of drug. Saturation solubility (p-value <0.05) demonstrated improved solubility of drug when enclosed in linseed nanoparticles. Nanoprecipitation surpasses emulsion solvent evaporation in dissolution test by possessing smaller size. Acute oral toxicity study indicated no significant changes in behavioral, clinical or histopathological parameters of control and experimental groups. CONCLUSION: The in vitro release of ezetimibe was augmented by enhancing aqueous solubility through devised nanoparticles. Thus, linseed mucilage could act as biopolymer in the fabrication of nanoparticle formulation. The acute oral toxicological investigations provided evidence that LUMNs were safe after oral administration.

ß-cyclodextrin chitosan-based hydrogels with tunable pH-responsive properties for controlled release of acyclovir: design, characterization, safety, and pharmacokinetic evaluation.

In this work, series of pH-responsive hydrogels (FMA1-FMA9) were synthesized, characterized, and evaluated as potential carrier for oral delivery of an antiviral drug, acyclovir (ACV). Different proportions of ß-cyclodextrin (ß-CD), chitosan (CS), methacrylic acid (MAA) and N' N'-methylenebis-acrylamide (MBA) were used to fabricate hydrogels via free radical polymerization technique. Fourier transform infrared spectroscopy confirmed fabrication of new polymeric network, with successful incorporation of ACV. Scanning electron microscopy (SEM) indicated presence of slightly porous structure. Thermal analysis indicated enhanced thermal stability of polymeric network. Swelling studies were carried out at 37 °C in simulated gastric and intestinal fluids. The drug release data was found best fit to zero-order kinetics. The preliminary investigation of developed hydrogels showed a pH-dependent swelling behavior and drug release pattern. Acute oral toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of Wistar rats. Pharmacokinetic study indicated that developed hydrogels caused a significant increase in oral bioavailability of ACV in rabbit plasma as compared to oral suspension when both were administered at a single oral dose of 20 mg kg-1 bodyweight. Hence, developed hydrogel formulation could be used as potential candidate for controlled drug delivery of an antiviral drug acyclovir.

Fabrication, Characterization and Toxicity Evaluation of Chemically Cross linked Polymeric Network for Sustained Delivery of Metoprolol Tartrate.

Natural mucilages are auspicious biodegradable polymeric materials. The aim of the present research work was to elucidate the characteristics of quince mucilage-based polymeric network for sustained delivery of metprolol tartrate and its toxicity evaluation. Mucilage was extracted by hot water extraction, and characterization of quince mucilage was accomplished by using Fourier transform infrared (FTIR) spectroscopy. Different batches of quince mucilage polymeric network were prepared by free radical polymerization by utilizing varying ratios of quince mucilage, acrylamide and crosslinker. Degree of swelling depends on concentration of mucilage, monomer and also on crosslinking density of polymeric network. FTIR illustrates proficient grafting, and morphological (scanning electron microscopy) analysis signified porous design. Hence, quince mucilage-based design was encouraging for sustained delivery of metprolol tartrate and acute toxicity evaluation proved that mucilage-based network was safe for oral drug delivery system.

SubID, a non-median dichotomization tool for heterogeneous populations, reveals the pan-cancer significance of INPP4B and its regulation by EVI1 in AML.

Our previous studies demonstrated that INPP4B, a member of the PI3K/Akt signaling pathway, is overexpressed in a subset of AML patients and is associated with lower response to chemotherapy and shorter survival. INPP4B expression analysis in AML revealed a right skewed frequency distribution with 25% of patients expressing significantly higher levels than the majority. The 75% low/25% high cut-off revealed the prognostic power of INPP4B expression status in AML, which would not have been apparent with a standard median cut-off approach. Our identification of a clinically relevant non-median cut-off for INPP4B indicated a need for a generalizable non-median dichotomization approach to optimally study clinically relevant genes. To address this need, we developed Subgroup Identifier (SubID), a tool which examines the relationship between a continuous variable (e.g. gene expression), and a test parameter (e.g. CoxPH or Fisher's exact P values). In our study, Fisher's exact SubID was used to reveal EVI1 as a transcriptional regulator of INPP4B in AML; a finding which was validated in vitro. Next, we used CoxPH SubID to conduct a pan-cancer analysis of INPP4B's prognostic significance. Our analysis revealed that INPP4Blow is associated with shorter survival in kidney clear cell, liver hepatocellular, and bladder urothelial carcinomas. Conversely, INPP4Blow was shown to be associated with increased survival in pancreatic adenocarcinoma in three independent datasets. Overall, our study describes the development and application of a novel subgroup identification tool used to identify prognostically significant rare subgroups based upon gene expression, and for investigating the association between a gene with skewed frequency distribution and potentially important upstream and downstream genes that relate to the index gene.

A study of polypharmacy with second generation antipsychotics in patients with severe and persistent mental illness.

BACKGROUND: There is a paucity of empirical support for polypharmacy with second generation (atypical) antipsychotics (SGAs), especially in understudied populations. OBJECTIVE: To investigate the frequency, effectiveness, and safety of this practice in patients with severe and persistent mental illness who are chronically hospitalized. METHODS: A chart review was conducted at a state psychiatric hospital in Syracuse, NY. The study subjects (N=26) were chronically hospitalized individuals with DSM-IV diagnoses of schizophrenia or schizoaffective disorder who were initially prescribed at least one SGA and then received at least one other SGA during the study period. Demographic and clinical data were collected. Baseline and 6-month assessments were compared for statistical significance (p<0.05). RESULTS: Of the 117 chronically hospitalized inpatients at the study center, 22.2% (N=26) received treatment regimens involving polypharmacy with SGAs. These patients as a group achieved statistically significant reductions on their scores on the Brief Psychiatric Rating Scale (34.2 +/- 11.0 compared with 25.3 +/- 11.8; p=0.016) and the Clinical Global Impressions-Improvement Scale (5.5 +/- 0.6 compared with. 5.0 +/- 0.8; p=0.016) at 6 months. There was a significant decrease in the use of prn medications (7.6 +/- 19.6 compared with 1.6 +/- 2.6; p<0.04). However, the number of patients receiving anticholinergic medications increased from 5 to 8 (p<0.04). CONCLUSIONS: Polypharmacy with SGAs is quite frequent among chronic inpatients with severe and persistent mental illness despite a limited empirical database supporting its use. The results of our pilot study do not demonstrate the effectiveness and safety of this practice. However, methodological shortcomings may have contributed to our failure to detect a true, positive effect. Controlled studies are needed to accurately determine the risks and benefits of SGA polypharmacy.

Death receptor 5 regulation during selenium-mediated apoptosis in human prostate cancer cells.

Selenium is an essential micronutrient that is currently being tested for prostate cancer chemoprevention. In spite of its significant promise as a chemopreventive agent, the molecular mechanisms of selenium-mediated effects remain to be elucidated. Recent evidence suggests that selenium may mediate its chemopreventive effects by inducing apoptosis in human prostate cancer cells. Here we report that selenium-mediated apoptosis appears to involve membrane death receptor, DR5-dependent pathway in human prostate cancer cells. Selenium specifically upregulated DR5 expression but not that of DR4. Selenium upregulation of DR5 was coupled with caspase 8 activation and Bid cleavage thereby suggesting the existence of a potential cross-talk between the DR5 and the mitochondrial pathways. Thus, our results suggest that DR5 is specifically regulated by selenium and its activation may play an important role in selenium-mediated chemoprevention.

Lovastatin sensitizes lung cancer cells to ionizing radiation: modulation of molecular pathways of radioresistance and tumor suppression.

INTRODUCTION: In this study, we investigated the effect of the 3-hydroxy-3-methylgutaryl-CoA reductase inhibitor lovastatin, as a sensitizer of lung cancer cells to ionizing radiation (IR). METHODS: A549 lung adenocarcinoma cells were treated with 0 to 50 µM lovastatin alone or in combination with 0 to 8 Gy IR and subjected to clonogenic survival and proliferation assays. To assess the mechanism of drug action, we examined the effects of lovastatin and IR on the epidermal growth factor (EGF) receptor and AMP-activated kinase (AMPK) pathways and on apoptotic markers and the cell cycle. RESULTS: Lovastatin inhibited basal clonogenic survival and proliferation of A549 cells and sensitized them to IR. This was reversed by mevalonate, the product of 3-hydroxy-3-methylgutaryl-CoA reductase. Lovastatin attenuated selectively EGF-induced phosphorylation of EGF receptor and Akt, and IR-induced Akt phosphorylation, in a mevalonate-sensitive fashion, without inhibition on extracellular signal-regulated kinase 1/2 phosphorylation by either stimulus. IR phosphorylated and activated the metabolic sensor and tumor suppressor AMPK, but lovastatin enhanced basal and IR-induced AMPK phosphorylation. The drug inhibited IR-induced expression of p53 and the cyclin-dependent kinase inhibitors p21(cip1) and p27(kip1), but caused a redistribution of cells from G1-S phase (control and radiated cells) and G2-M phase (radiated cells) of cell cycle into apoptosis. The latter was also evident by induction of nuclear fragmentation and cleavage of caspase 3 by lovastatin in both control and radiated cells. CONCLUSIONS: We suggest that lovastatin inhibits survival and induces radiosensitization of lung cancer cells through induction of apoptosis, which may be mediated by a simultaneous inhibition of the Akt and activation of the AMPK signaling pathways.

Resveratrol enhances prostate cancer cell response to ionizing radiation. Modulation of the AMPK, Akt and mTOR pathways.

BACKGROUND: Prostate cancer (PrCa) displays resistance to radiotherapy (RT) and requires radiotherapy dose escalation which is associated with greater toxicity. This highlights a need to develop radiation sensitizers to improve the efficacy of RT in PrCa. Ionizing radiation (IR) stimulates pathways of IR-resistance and survival mediated by the protein kinase Akt but it also activates the metabolic energy sensor and tumor suppressor AMP-Activated Protein Kinase (AMPK). Here, we examined the effects of the polyphenol resveratrol (RSV) on the IR-induced inhibition of cell survival, modulation of cell cycle and molecular responses in PrCa cells. METHODS: Androgen-insensitive (PC3), sensitive (22RV1) PrCa and PNT1A normal prostate epithelial cells were treated with RSV alone (2.5-10 µM) or in combination with IR (2-8 Gy). Clonogenic assays, cell cycle analysis, microscopy and immunoblotting were performed to assess survival, cell cycle progression and molecular responses. RESULTS: RSV (2.5-5 µM) inhibited clonogenic survival of PC3 and 22RV1 cells but not of normal prostate PNT1A cells. RSV specifically sensitized PrCa cells to IR, induced cell cycle arrest at G1-S phase and enhanced IR-induced nuclear aberrations and apoptosis. RSV enhanced IR-induced expression of DNA damage (γH2Ax) and apoptosis (cleaved-caspase 3) markers as well as of the cell cycle regulators p53, p21(cip1) and p27(kip1). RSV enhanced IR-activation of ATM and AMPK but inhibited basal and IR-induced phosphorylation of Akt. CONCLUSIONS: Our results suggest that RSV arrests cell cycle, promotes apoptosis and sensitizes PrCa cells to IR likely through a desirable dual action to activate the ATM-AMPK-p53-p21(cip1)/p27(kip1) and inhibit the Akt signalling pathways.

Ionizing radiation activates AMP-activated kinase (AMPK): a target for radiosensitization of human cancer cells.

PURPOSE: Adenosine monophosphate (AMP)-activated kinase (AMPK) is a molecular energy sensor regulated by the tumor suppressor LKB1. Starvation and growth factors activate AMPK through the DNA damage sensor ataxia-telangiectasia mutated (ATM). We explored the regulation of AMPK by ionizing radiation (IR) and its role as a target for radiosensitization of human cancer cells. METHODS AND MATERIALS: Lung, prostate, and breast cancer cells were treated with IR (2-8 Gy) after incubation with either ATM or AMPK inhibitors or the AMPK activator metformin. Then, cells were subjected to either lysis and immunoblotting, immunofluorescence microscopy, clonogenic survival assays, or cell cycle analysis. RESULTS: IR induced a robust phosphorylation and activation of AMPK in all tumor cells, independent of LKB1. IR activated AMPK first in the nucleus, and this extended later into cytoplasm. The ATM inhibitor KU-55933 blocked IR activation of AMPK. AMPK inhibition with Compound C or anti-AMPK alpha subunit small interfering RNA (siRNA) blocked IR induction of the cell cycle regulators p53 and p21(waf/cip) as well as the IR-induced G2/M arrest. Compound C caused resistance to IR, increasing the surviving fraction after 2 Gy, but the anti-diabetic drug metformin enhanced IR activation of AMPK and lowered the surviving fraction after 2 Gy further. CONCLUSIONS: We provide evidence that IR activates AMPK in human cancer cells in an LKB1-independent manner, leading to induction of p21(waf/cip) and regulation of the cell cycle and survival. AMPK appears to (1) participate in an ATM-AMPK-p21(waf/cip) pathway, (2) be involved in regulation of the IR-induced G2/M checkpoint, and (3) may be targeted by metformin to enhance IR responses.

Differential responses of human brain cells to West Nile virus infection.

In recent years, West Nile virus (WNV) has emerged as a major cause of encephalitis in the United States. However, the neuropathogenesis of this flavivirus is poorly understood. In the present study, the authors used primary human brain cell cultures to investigate two neuropathogenic features: viral replication and induction of cytokines. Although neurons and astrocytes were found to support productive WNV infection, viral growth was poorly permissive in microglial cells. Compared to neuronal cultures that sustained viral growth for at least 2 weeks, replication peaked in astrocytes by 72 h post infection. In response to viral infection, astrocytes produced chemokines (CXCL10 and CCL5), but none of the cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, interferon alpha or gamma) tested could be detected. Although microglial cells failed to support viral replication, WNV induced production of the proinflammatory cytokines IL-6 and TNF-alpha. Microglial cells also released robust amounts of the chemokines CXCL10 and CCL2, as well as lower levels of CCL5, in response to WNV infection. WNV-induced chemokine and cytokine production by microglia was coupled with activation of mitogen-activated protein kinase (MAPK) intracellular signaling pathways. Inhibition of p38 MAPK decreased chemokine production in response to WNV. Taken together, these findings suggest that microglial cell responses may influence the neuropathogenesis of WNV infection.