The MRN complex is transcriptionally regulated by MYCN during neural cell proliferation to control replication stress

The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathogenesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.Cell Death and Differentiation advance online publication, 12 June 2015; doi:10.1038/cdd.2015.81

Do patients adhere to over-the-counter artemisinin combination therapy for malaria? evidence from an intervention study in Uganda

<p>Abstract</p> <p>Background</p> <p>Increasing affordability of artemisinin combination therapy (ACT) in the African retail sector could be critical to expanding access to effective malaria treatment, but must be balanced by efforts to protect the efficacy of these drugs. Previous research estimates ACT adherence rates among public sector patients, but adherence among retail sector purchasers could differ substantially. This study aimed to estimate adherence rates to subsidized, over-the-counter ACT in rural Uganda.</p> <p>Methods</p> <p>An intervention study was conducted with four licensed drug shops in Eastern Uganda in December 2009. Artemether-lumefantrine (AL) was made available for sale at a 95% subsidy over-the counter. Customers completed a brief survey at the time of purchase and then were randomly assigned to one of three study arms: no follow-up, follow-up after two days or follow-up after three days. Surveyors recorded the number of pills remaining through blister pack observation or through self-report if the pack was unavailable. The purpose of the three-day follow-up arm was to capture non-adherence in the sense of an incomplete treatment course ("under-dosing"). The purpose of the two-day follow-up arm was to capture whether participants completed the full course too soon ("over-dosing").</p> <p>Results</p> <p>Of the 106 patients in the two-day follow-up sample, 14 (13.2%) had finished the entire treatment course by the second day. Of the 152 patients in the three-day follow-up sample, 49 (32.2%) were definitely non-adherent, three (2%) were probably non-adherent and 100 (65.8%) were probably adherent. Among the 52 who were non-adherent, 31 (59.6%) had more than a full day of treatment remaining.</p> <p>Conclusions</p> <p>Overall, adherence to subsidized ACT purchased over-the-counter was found to be moderate. Further, a non-trivial fraction of those who complete treatment are taking the full course too quickly. Strategies to increase adherence in the retail sector are needed in the context of increasing availability and affordability of ACT in this sector.</p

The carbon footprint of power-to-synthetic natural gas by photovoltaic solar powered electrochemical reduction of CO2

The search for more sustainable production and consumption patterns entails the integration of emerging edge-cutting technologies. Holistic studies are needed in order to accurately evaluate properly the environmental competitiveness of the suggested solutions. Among those alternatives, it has been suggested the utilisation of CO2 for the production of synthetic natural gas, the so-called Power-to-Gas (PtG) technology. In this work, we use the PtG technology to analyse the environmental rationality in terms of the carbon footprint (CF) of a Photovoltaic (PV) solar powered Electrochemical Reduction (ER) process for the utilisation of CO2 as carbon source for the production of CH4. This synthetic natural gas is ready to be injected into the transmission and distribution network. The raw materials for the process are a source of CO2 (mixed with different ratios of N2), H2O and electricity from PV solar. The separated products are CH4, C2H4, H2/CO, O2 and HCOOH. The reaction, separation/purification and compression stages needed to deliver commercially distributable products are included. Mass and energy balances were used to create a black-box model. The input to the model is the faradaic efficiency and cathodic potential of the best cathodesperforming at lab-scale (over 60% faradaic efficiency towards CH4). It was assumed that cathodes were long-lasting. The output of the model is the distribution of products (related to 1 kg of pure CH4) and the energy consumption at each of the aforementioned stages. The overall CF is then calculated as a function of the CF PV solar reference and the total energy consumption. The effect on the distribution of each stage to the total energy consumption of both the purity of the CO2 stream and the conversion of CO2 in the reactor was analysed. The results show that the principal contributor to the total energy consumption is the ER of CH4 across all CO2concentrations and conversions. When a CO2 conversion of 50% is chosen together with an inlet stream with a N2:CO2 ratio of 24, the electricity consumption of the process is between 2.6 and 6.2 times the minimum obtained for a reference ER reactor including the separation and compression of gaseous products (18.5 kWh kg−1 of CH4). The use of PV solar energywith low CF (14⋅10−3 kg kWh−1) allows the current lab-scale performers to even the CF associated with the average world production of natural gas when the valorisation of C2H4 is included (∼1.0 kg kg−1 of CH4).Authors gratefully acknowledge the funding provided by the State Research Agency, Ministry of Science, Innovation, and Universities (Spain) through the project CTQ2016-76231-C2-1-R

Non-medical prescribing versus medical prescribing for acute and chronic disease management in primary and secondary care.

The aim of this Cochrane review was to find out if prescribing by health professionals other than doctors delivers comparable outcomes to prescribing by doctors. Cochrane researchers collected and analysed all relevant studies to answer this question and found 46 studies. Key messages With appropriate training and support, nurses and pharmacists are able to prescribe medicines as part of managing a range of conditions to achieve comparable health management outcomes to doctors. The majority of studies focus on chronic disease management in higher-income counties where there is generally a moderate-certainty of evidence supporting similar outcomes for the markers of disease in high blood pressure, diabetes, and high cholesterol. Further high-quality studies are needed in poorer countries and to better quantify differences in prescribing outcomes for adverse events, and to determine health economic outcomes. Further studies could also focus more specifically on the prescribing component of care. What was studied in the review? A number of countries allow health professionals other than doctors to prescribe medicines. This shift in roles is thought to provide improved and timely access to medicines for consumers where there are shortages of doctors or the health system is facing pressures in coping with the burden of disease. In addition, this task shift has been supported by a number of governments as a way to more appropriately use the skills of health professionals, such as nurses and pharmacists, in the care of patients. We compared the outcomes of any healthcare workers who were prescribing with a high degree of autonomy with medical prescribers in the hospital or community setting in low-, middle- and high-income countries. What are the main results of the review? This review found 45 studies where nurses and pharmacists with high levels of prescribing autonomy were compared with usual care medical prescribers. A further study compared nurse prescribing with guideline support with usual nurse prescribing care. No studies were found with other health professionals or lay prescribers. Four nurse prescribing studies were undertaken in the low- and middle-income settings of Colombia, South Africa, Uganda, and Thailand. The remainder of studies were undertaken in high-income Western countries. Forty-two studies were based in a community setting, two studies were located in hospitals, one study in the workplace, and one study in an aged care facility. Prescribing was but one part of many health-related interventions, particularly in the management of chronic disease. The review found that the outcomes for non-medical prescribers were comparable to medical prescribers for: high blood pressure (moderate-certainty of evidence); diabetes control (high-certainty of evidence); high cholesterol (moderate-certainty of evidence); adverse events (low-certainty of evidence); patients adhering to their medication regimeans (moderate-certainty of evidence); patient satisfaction with care (moderate-certainty of evidence); and health-related quality of life (moderate-certainty of evidence). Pharmacists and nurses with varying levels of undergraduate, postgraduate, and specific on-the-job training related to the disease or condition were able to deliver comparable prescribing outcomes to doctors. Non-medical prescribers frequently had medical support available to facilitate a collaborative practice model

Current concepts in the prevention of pathogen transmission via blood/plasma-derived products for bleeding disorders

The pathogen safety of blood/plasma-derived products has historically been a subject of significant concern to the medical community. Measures such as donor selection and blood screening have contributed to increase the safety of these products, but pathogen transmission does still occur. Reasons for this include lack of sensitivity/specificity of current screening methods, lack of reliable screening tests for some pathogens (e.g. prions) and the fact that many potentially harmful infectious agents are not routinely screened for. Methods for the purification/inactivation of blood/plasma-derived products have been developed in order to further reduce the residual risk, but low concentrations of pathogens do not necessarily imply a low level of risk for the patient and so the overall challenge of minimising risk remains. This review aims to discuss the variable level of pathogenic risk and describes the current screening methods used to prevent/detect the presence of pathogens in blood/plasma-derived products

Glucocorticoids modulate the biosynthesis and processing of prothyrotropin releasing-hormone (proTRH).

The thyrotropin- (TRH) releasing hormone precursor (26 kDa) undergoes proteolytic cleavage at either of two sites, generating N-terminal 15 kDa/9.5 kDa or C-terminal 16.5/10 kDa intermediate forms that are processed further to yield five copies of TRH-Gly and seven non-TRH peptides. Glucocorticoids (Gcc) have been shown to enhance TRH gene expression in three different cell systems in vitro, an effect that occurs, at least in part, through transcriptional activation. Although this implies that an increase of TRH prohormone biosynthesis would take place, this had not been demonstrated as yet. We report here that the synthetic glucocorticoid dexamethasone (Dex) substantially elevated the de novo biosynthesis of the intact 26-kDa TRH prohormone and its intermediate products of processing in cultured anterior pituitary cells, an observation that is consistent with an overall upregulation of both the biosynthesis and degradation of the TRH precursor. We reasoned that Gcc may act not only at the transcriptional, but also at the translational/posttranslational level. To address this question we chose a different cell system, AtT20 cells transfected with a cDNA encoding preproTRH. Since TRH gene expression in these cells is driven by the CMV-IE promoter and not by an endogenous "physiological" promoter, these cells provide an ideal model to study selectively the effects of Gcc on the translation and posttranslational processing of proTRH without interference from a direct transcriptional activation of the TRH gene. Dex caused a significant 75.7% increase in newly synthesized 26-kDa TRH prohormone, suggesting that the glucocorticoid raised the translation rate. We then demonstrated that Dex treatment accelerated TRH precursor processing. Of interest, processing of the N- vs the C-terminal intermediate was influenced differentially by the glucocorticoid. Although the N-terminal intermediate product of processing accumulated, the C-terminal intermediate was degraded more rapidly. Consistent with these observations was the finding that the intracellular accumulation of the N-terminally derived peptide preproTRH 25-50 was enhanced, but levels of the C-terminally derived peptide preproTRH208-255 were reduced. Accumulation of TRH itself, whose five copies are N- and C-terminally derived, was also enhanced. We conclude that Gcc induce changes in the biosynthesis and processing of proTRH by increasing the translation rate and by differentially influencing the processing of N- vs C-terminal intermediates of the precursor molecule. These effects of Gcc at the translational and posttranslational levels result in an increase in TRH production accompanied by differential effects on the accumulation of N- and C-terminal non-TRH peptides

Glucocorticoids modulate the biosynthesis and processing of prothyrotropin releasing-hormone (proTRH).

The thyrotropin- (TRH) releasing hormone precursor (26 kDa) undergoes proteolytic cleavage at either of two sites, generating N-terminal 15 kDa/9.5 kDa or C-terminal 16.5/10 kDa intermediate forms that are processed further to yield five copies of TRH-Gly and seven non-TRH peptides. Glucocorticoids (Gcc) have been shown to enhance TRH gene expression in three different cell systems in vitro, an effect that occurs, at least in part, through transcriptional activation. Although this implies that an increase of TRH prohormone biosynthesis would take place, this had not been demonstrated as yet. We report here that the synthetic glucocorticoid dexamethasone (Dex) substantially elevated the de novo biosynthesis of the intact 26-kDa TRH prohormone and its intermediate products of processing in cultured anterior pituitary cells, an observation that is consistent with an overall upregulation of both the biosynthesis and degradation of the TRH precursor. We reasoned that Gcc may act not only at the transcriptional, but also at the translational/posttranslational level. To address this question we chose a different cell system, AtT20 cells transfected with a cDNA encoding preproTRH. Since TRH gene expression in these cells is driven by the CMV-IE promoter and not by an endogenous "physiological" promoter, these cells provide an ideal model to study selectively the effects of Gcc on the translation and posttranslational processing of proTRH without interference from a direct transcriptional activation of the TRH gene. Dex caused a significant 75.7% increase in newly synthesized 26-kDa TRH prohormone, suggesting that the glucocorticoid raised the translation rate. We then demonstrated that Dex treatment accelerated TRH precursor processing. Of interest, processing of the N- vs the C-terminal intermediate was influenced differentially by the glucocorticoid. Although the N-terminal intermediate product of processing accumulated, the C-terminal intermediate was degraded more rapidly. Consistent with these observations was the finding that the intracellular accumulation of the N-terminally derived peptide preproTRH 25-50 was enhanced, but levels of the C-terminally derived peptide preproTRH208-255 were reduced. Accumulation of TRH itself, whose five copies are N- and C-terminally derived, was also enhanced. We conclude that Gcc induce changes in the biosynthesis and processing of proTRH by increasing the translation rate and by differentially influencing the processing of N- vs C-terminal intermediates of the precursor molecule. These effects of Gcc at the translational and posttranslational levels result in an increase in TRH production accompanied by differential effects on the accumulation of N- and C-terminal non-TRH peptides

Glucocorticoids modulate the biosynthesis and processing of prothyrotropin releasing-hormone (proTRH).

The thyrotropin- (TRH) releasing hormone precursor (26 kDa) undergoes proteolytic cleavage at either of two sites, generating N-terminal 15 kDa/9.5 kDa or C-terminal 16.5/10 kDa intermediate forms that are processed further to yield five copies of TRH-Gly and seven non-TRH peptides. Glucocorticoids (Gcc) have been shown to enhance TRH gene expression in three different cell systems in vitro, an effect that occurs, at least in part, through transcriptional activation. Although this implies that an increase of TRH prohormone biosynthesis would take place, this had not been demonstrated as yet. We report here that the synthetic glucocorticoid dexamethasone (Dex) substantially elevated the de novo biosynthesis of the intact 26-kDa TRH prohormone and its intermediate products of processing in cultured anterior pituitary cells, an observation that is consistent with an overall upregulation of both the biosynthesis and degradation of the TRH precursor. We reasoned that Gcc may act not only at the transcriptional, but also at the translational/posttranslational level. To address this question we chose a different cell system, AtT20 cells transfected with a cDNA encoding preproTRH. Since TRH gene expression in these cells is driven by the CMV-IE promoter and not by an endogenous "physiological" promoter, these cells provide an ideal model to study selectively the effects of Gcc on the translation and posttranslational processing of proTRH without interference from a direct transcriptional activation of the TRH gene. Dex caused a significant 75.7% increase in newly synthesized 26-kDa TRH prohormone, suggesting that the glucocorticoid raised the translation rate. We then demonstrated that Dex treatment accelerated TRH precursor processing. Of interest, processing of the N- vs the C-terminal intermediate was influenced differentially by the glucocorticoid. Although the N-terminal intermediate product of processing accumulated, the C-terminal intermediate was degraded more rapidly. Consistent with these observations was the finding that the intracellular accumulation of the N-terminally derived peptide preproTRH 25-50 was enhanced, but levels of the C-terminally derived peptide preproTRH208-255 were reduced. Accumulation of TRH itself, whose five copies are N- and C-terminally derived, was also enhanced. We conclude that Gcc induce changes in the biosynthesis and processing of proTRH by increasing the translation rate and by differentially influencing the processing of N- vs C-terminal intermediates of the precursor molecule. These effects of Gcc at the translational and posttranslational levels result in an increase in TRH production accompanied by differential effects on the accumulation of N- and C-terminal non-TRH peptides