HTA on DVD/Health technology assessment, May 1, 2024
Background: Information on the quality of life of people hospitalised with COVID-19 is important,... more Background: Information on the quality of life of people hospitalised with COVID-19 is important, both in assessing the burden of disease and the cost-effectiveness of treatments. However, there were potential barriers to collecting such evidence. Objective: To review the existing evidence on quality of life for people hospitalised with COVID-19, with a focus on the amount of evidence available and methods used. Design: A scoping review with systematic searches. Results: A total of 35 papers were selected for data extraction. The most common study type was economic evaluation (N = 13), followed by cross-sectional (N = 10). All economic evaluations used published utility values for other conditions to represent COVID-19 inpatients' quality of life. The most popular quality-of-life survey measure was the Pittsburgh Sleep Quality Index (N = 8). There were 12 studies that used a mental health-related survey and 12 that used a sleep-related survey. Five studies used EQ-5D, but only one collected responses from people in the acute phase of COVID-19. Studies reported a negative impact on quality of life for people hospitalised with COVID-19, although many studies did not include a formal comparison group. Limitations: Although it used systematic searches, this was not a full systematic review. Conclusion: Quality-of-life data were collected from people hospitalised with COVID-19 from relatively early in the pandemic. However, there was a lack of consensus as to what survey measures to use, and few studies used generic health measures. Economic evaluations for COVID-19 treatments did not use utilities collected from people with COVID-19. In future health crises, researchers should be vigilant for opportunities to collect quality-of-life data from hospitalised patients but should try to coordinate as well as ensuring generic health measures are used more.
http://isrctn.com/, May 17, 2021
http://isrctn.com/, Dec 19, 2019
Ryanodine receptors are homotetrameric intracellular calcium release channels. The efficiency of ... more Ryanodine receptors are homotetrameric intracellular calcium release channels. The efficiency of these channels is underpinned by exceptional rates of cation translocation through the open channel and this is achieved at the expense of the high degree of selectivity characteristic of many other types of channel. Crystallization of prokaryotic potassium channels has provided insights into the structures and mechanisms responsible for ion selection and movement in these channels, however no equivalent structural detail is currently available for ryanodine receptors. Nevertheless both molecular modeling and cryo-electron microscopy have identified the probable pore-forming region (PFR) of the ryanodine receptor (RyR) and suggest that this region contains structural elements equivalent to those of the PFRs of potassium-selective channels. The aim of the current study was to establish if the isolated putative cardiac RyR (RyR2) PFR could form a functional ion channel. We have expressed and purified the RyR2 PFR and shown that function is retained following reconstitution into planar phospholipid bilayers. Our data provide the first direct experimental evidence to support the proposal that the conduction pathway of RyR2 is formed by structural elements equivalent to those of the potassium channel PFR.
Advances in Experimental Medicine and Biology, 2012
In excitable tissues, the ryanodine receptor Ca(2+) release channel (RyR) protein complex regulat... more In excitable tissues, the ryanodine receptor Ca(2+) release channel (RyR) protein complex regulates excitation-contraction coupling, exocytosis, gene expression and apoptosis. Defects in RyR function, in genetic or acquired pathologies, lead to massive disruptions of Ca(2+) release that can be lethal. Therefore, RyR has emerged as a putative therapeutic target and an increasing number of RyR-targeting drugs are currently being tested.Nonetheless this large-size channel is still a mystery in terms of structure, which hinders full characterization of the properties of this central protein. This chapter is dedicated to the methods available to examine RyR structure and function. The aim of the article is to concentrate on contemporary methodologies rather than focusing overtly on the progress that has been achieved using these techniques. Here we review a series of reliable approaches that are routinely employed to investigate this channel. Technical limitations are discussed, and technological developments are presented. This work is not a handbook, but it can be used as a resource and a starting point for the investigation of RyR at different levels of resolution.
Background: In many K ϩ channels, gating requires flexing of inner helices at glycine residues wi... more Background: In many K ϩ channels, gating requires flexing of inner helices at glycine residues within a "hinge motif." An analogous motif is present in the ryanodine receptor channel. Results: Mutation of ryanodine receptor "hinge" glycines produces varying effects on gating. Conclusion: Ryanodine receptors do not contain a typical glycine hinge. Significance: This work provides new insights into mechanisms of ryanodine receptor function. Ryanodine receptor channels (RyR) are key components of striated muscle excitation-contraction coupling, and alterations in their function underlie both inherited and acquired disease. A full understanding of the disease process will require a detailed knowledge of the mechanisms and structures involved in RyR function. Unfortunately, high-resolution structural data, such as exist for K ؉-selective channels, are not available for RyR. In the absence of these data, we have used modeling to identify similarities in the structural elements of K ؉ channel pore-forming regions and postulated equivalent regions of RyR. This has identified a sequence of residues in the cytosolic cavity-lining transmembrane helix of RyR (G 4864 LIIDA 4869 in RyR2) analogous to the glycine hinge motif present in many K ؉ channels. Gating in these K ؉ channels can be disrupted by substitution of residues for the hinge glycine. We investigated the involvement of glycine 4864 in RyR2 gating by monitoring properties of recombinant human RyR2 channels in which this glycine is replaced by residues that alter gating in K ؉ channels. Our data demonstrate that introducing alanine at position 4864 produces no significant change in RyR2 function. In contrast, function is altered when glycine 4864 is replaced by either valine or proline, the former preventing channel opening and the latter modifying both ion translocation and gating. Our studies reveal novel information on the structural basis of RyR gating, identifying both similarities with, and differences from, K ؉ channels. Glycine 4864 is not absolutely required for channel gating, but some flexibility at this point in the cavity-lining transmembrane helix is necessary for normal RyR function.
Criteria for inclusion in the Health Technology Assessment journal Reports are published in Healt... more Criteria for inclusion in the Health Technology Assessment journal Reports are published in Health Technology Assessment (HTA) if (1) they have resulted from work for the HTA programme, and (2) they are of a sufficiently high scientific quality as assessed by the reviewers and editors. Reviews in Health Technology Assessment are termed 'systematic' when the account of the search appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.
Interactions between a membrane protein and the lipid molecules that surround it in the membrane ... more Interactions between a membrane protein and the lipid molecules that surround it in the membrane are important in determining the structure and function of the protein. These interactions can be pictured at the molecular level using fluorescence spectroscopy, making use of the ability to introduce tryptophan residues into regions of interest in bacterial membrane proteins. Fluorescence quenching methods have been developed to study lipid binding separately on the two sides of the membrane. Lipid binding to the surface of the mechanosensitive channel MscL is heterogeneous, with a hot-spot for binding anionic lipid on the cytoplasmic side, associated with a cluster of three positively charged residues. The environmental sensitivity of tryptophan fluorescence emission has been used to identify the residues at the ends of the hydrophobic core of the second transmembrane α-helix in MscL. The efficiency of hydrophobic matching between MscL and the surrounding lipid bilayer is high. Fluore...
IntroductionSepsis is a common, potentially life-threatening complication of infection. The optim... more IntroductionSepsis is a common, potentially life-threatening complication of infection. The optimal treatment for sepsis includes prompt antibiotics and intravenous fluids, facilitated by its early and accurate recognition. Currently, clinicians identify and assess severity of suspected sepsis using validated clinical scoring systems. In England, the National Early Warning Score 2 (NEWS2) has been mandated across all National Health Service (NHS) trusts and ambulance organisations. Like many clinical scoring systems, NEWS2 should not be used without clinical judgement to determine either the level of acuity or a diagnosis. Despite this, there is a tendency to overemphasise the score in isolation in patients with suspected infection, leading to the overprescription of antibiotics and potentially treatment-related complications and rising antimicrobial resistance. The biomarker procalcitonin (PCT) has been shown to be useful in specific circumstances to support appropriate antibiotics...
Background Less than 10% of hospitalized cases in the United Kingdom during the first wave of the... more Background Less than 10% of hospitalized cases in the United Kingdom during the first wave of the pandemic had bacterial coinfection, but approximately 75% were prescribed antibiotics contrary to NICE guidelines. We have evaluated the relationship between antibiotic prescribing and biomarker use, in hospitalized adult patients with COVID-19 in the UK, as synthesis defined by the pandemic timeline, particularly during ‘Wave 2’ is lacking. Clinical outcomes were compared in the context of antimicrobial stewardship. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT) and white cell count (WCC) were selected based on clinical relevance. Methods Studies (n = 300) dated 2019–22 were identified via EMBASE and Web of Science databases, using relevant search terms. Wave 1 and Wave 2 parameters were defined by the Office for National Statistics. Literature selection was organized by the preferred reporting items for systematic reviews and meta-analyses (PRISMA)...
559-Pos Board B314 The Cardiac Ryanodine Receptor (RyR2): Investigating Mechanisms of Gating at t... more 559-Pos Board B314 The Cardiac Ryanodine Receptor (RyR2): Investigating Mechanisms of Gating at the Selectivity Filter Jahn M. Firth, Joanne Euden, Alan J. Williams. Institute of Molecular and Experimental Medicine, Cardiff, United Kingdom. Ryanodine receptors (RyR) provide the pathway for release of intracellular calcium ions (Ca2þ) that initiate muscle contraction. Mutations in cardiac RyRs, (RyR2) underlie arrhythmia and sudden cardiac death. RyRs are therefore an attractive therapeutic target, howevermore information regarding structure and function is required.The enormoussizeofRyRsprecludes detailed structural analysis. Models, based on potassium channel templates, exist for the RyR poreforming region (PFR) providing an invaluable framework in which predictions of specific processes of ion translocation and gating mechanisms can be tested. Potassium channels have a conserved gating mechanism involving a distinct hydrogen-bonding network of residues at the selectivity filter th...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus responsible for the... more Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus responsible for the coronavirus disease 2019 (COVID-19) pandemic. Although COVID-19 is a viral illness, many patients admitted to hospital are prescribed antibiotics, based on concerns that COVID-19 patients may experience secondary bacterial infections, and the assumption that they may respond well to antibiotic therapy. This has led to an increase in antibiotic use for some hospitalised patients at a time when accumulating antibiotic resistance is a major global threat to health. Procalcitonin (PCT) is an inflammatory marker measured in blood samples and widely recommended to help diagnose bacterial infections and guide antibiotic treatment. The PEACH study will compare patient outcomes from English and Welsh hospitals that used PCT testing during the first wave of the COVID-19 pandemic with those from hospitals not using PCT. It will help to determine whether, and how, PCT testing should be used in the ...
<p>(A) The logarithm of the molecular weight was plotted against elution volumes for three ... more <p>(A) The logarithm of the molecular weight was plotted against elution volumes for three protein standards: (a) B-amylase (200 kDa), (b) carbonic anhydrase (29 kDa) and (c) cytochrome c (12.4 kDa) to create a calibration curve. The expected elution position of the hRyR2-PFR is shown as a dotted line. (B) Gel filtration trace of analytical standards.</p
<p>(A) shows Po of hRyR2-PFR at −60 mV with neomycin added to both sides of the channel. (B... more <p>(A) shows Po of hRyR2-PFR at −60 mV with neomycin added to both sides of the channel. (B) shows Po of hRyR2-PFR at +60 mV under the same conditions. Data are plotted as mean ±S.E.M for between three and six channels. Where differences between the means reach statistical significance, these are indicated by asterisks (**P<0.005).</p
<p>(A) Gel filtration trace of hRyR2-PFR showing void volume; and protein peak; (PFR) at 72... more <p>(A) Gel filtration trace of hRyR2-PFR showing void volume; and protein peak; (PFR) at 72 mls as predicted by analytical gel filtration. (B) Purification samples of hRyR2-PFR 1-Load, 2-affinity sample, 3-void, 4-main peak, 5-second affinity sample following GF.</p
<p>A plot of open probability (Po) plotted against voltage is shown in symmetrical 210 mM K... more <p>A plot of open probability (Po) plotted against voltage is shown in symmetrical 210 mM KCl. All points are mean values ±SD derived from three or more experiments. Error bars, where not visible, are within the symbol. The cartoon inset shows a stylized representation of a typical section of recording from a bilayer containing 3 hRyR2-PFR channels at −80 mV. The collective open probability of these channels (Po<sub>(N)</sub>) was determined as the time spent at level N (level 3 in this example), as a proportion of the total time of the recording using QuB, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066542#s2" target="_blank">Materials and Methods</a>.</p
<p>(A) Current voltage plots of hRyR2-PFR in symmetrical 210 mM (•), 610 mM (▴), and 810 mM... more <p>(A) Current voltage plots of hRyR2-PFR in symmetrical 210 mM (•), 610 mM (▴), and 810 mM (⧫) KCl. Solid lines are derived from linear regression to give the slope conductance. All points are mean values ±SE derived from four or more experiments. Error bars, where not visible, are within the symbol. (B) shows the change in slope conductance with an increase in K<sup>+</sup> concentration for WT hRyR2 (▴) and the PFR (•). Lines are nonlinear regression derived from a single-site binding hyperbola. All points are mean values ±SE derived from four or more experiments. Error bars are within the symbol.</p
<p>(A) shows recordings at −40 mV with closings shown as downward deflections. P<sub>... more <p>(A) shows recordings at −40 mV with closings shown as downward deflections. P<sub>o</sub> is extremely high with very rare closing events. Closings are often too short to be fully resolved. (B) shows recordings at −80 mV. Closings occur more frequently and dwell times within closed states are much longer. Closed levels are denoted by C with the hashed line representing the closed level.</p
<p>(A) The pore forming region of KcsA and (B) our analogy model for the pore forming regio... more <p>(A) The pore forming region of KcsA and (B) our analogy model for the pore forming region of RyR2, constructed using KcsA as a template. Two monomers are shown for clarity as PyMOL cartoon representations (DeLano Scientific LLC, CA, USA).</p
HTA on DVD/Health technology assessment, May 1, 2024
Background: Information on the quality of life of people hospitalised with COVID-19 is important,... more Background: Information on the quality of life of people hospitalised with COVID-19 is important, both in assessing the burden of disease and the cost-effectiveness of treatments. However, there were potential barriers to collecting such evidence. Objective: To review the existing evidence on quality of life for people hospitalised with COVID-19, with a focus on the amount of evidence available and methods used. Design: A scoping review with systematic searches. Results: A total of 35 papers were selected for data extraction. The most common study type was economic evaluation (N = 13), followed by cross-sectional (N = 10). All economic evaluations used published utility values for other conditions to represent COVID-19 inpatients' quality of life. The most popular quality-of-life survey measure was the Pittsburgh Sleep Quality Index (N = 8). There were 12 studies that used a mental health-related survey and 12 that used a sleep-related survey. Five studies used EQ-5D, but only one collected responses from people in the acute phase of COVID-19. Studies reported a negative impact on quality of life for people hospitalised with COVID-19, although many studies did not include a formal comparison group. Limitations: Although it used systematic searches, this was not a full systematic review. Conclusion: Quality-of-life data were collected from people hospitalised with COVID-19 from relatively early in the pandemic. However, there was a lack of consensus as to what survey measures to use, and few studies used generic health measures. Economic evaluations for COVID-19 treatments did not use utilities collected from people with COVID-19. In future health crises, researchers should be vigilant for opportunities to collect quality-of-life data from hospitalised patients but should try to coordinate as well as ensuring generic health measures are used more.
http://isrctn.com/, May 17, 2021
http://isrctn.com/, Dec 19, 2019
Ryanodine receptors are homotetrameric intracellular calcium release channels. The efficiency of ... more Ryanodine receptors are homotetrameric intracellular calcium release channels. The efficiency of these channels is underpinned by exceptional rates of cation translocation through the open channel and this is achieved at the expense of the high degree of selectivity characteristic of many other types of channel. Crystallization of prokaryotic potassium channels has provided insights into the structures and mechanisms responsible for ion selection and movement in these channels, however no equivalent structural detail is currently available for ryanodine receptors. Nevertheless both molecular modeling and cryo-electron microscopy have identified the probable pore-forming region (PFR) of the ryanodine receptor (RyR) and suggest that this region contains structural elements equivalent to those of the PFRs of potassium-selective channels. The aim of the current study was to establish if the isolated putative cardiac RyR (RyR2) PFR could form a functional ion channel. We have expressed and purified the RyR2 PFR and shown that function is retained following reconstitution into planar phospholipid bilayers. Our data provide the first direct experimental evidence to support the proposal that the conduction pathway of RyR2 is formed by structural elements equivalent to those of the potassium channel PFR.
Advances in Experimental Medicine and Biology, 2012
In excitable tissues, the ryanodine receptor Ca(2+) release channel (RyR) protein complex regulat... more In excitable tissues, the ryanodine receptor Ca(2+) release channel (RyR) protein complex regulates excitation-contraction coupling, exocytosis, gene expression and apoptosis. Defects in RyR function, in genetic or acquired pathologies, lead to massive disruptions of Ca(2+) release that can be lethal. Therefore, RyR has emerged as a putative therapeutic target and an increasing number of RyR-targeting drugs are currently being tested.Nonetheless this large-size channel is still a mystery in terms of structure, which hinders full characterization of the properties of this central protein. This chapter is dedicated to the methods available to examine RyR structure and function. The aim of the article is to concentrate on contemporary methodologies rather than focusing overtly on the progress that has been achieved using these techniques. Here we review a series of reliable approaches that are routinely employed to investigate this channel. Technical limitations are discussed, and technological developments are presented. This work is not a handbook, but it can be used as a resource and a starting point for the investigation of RyR at different levels of resolution.
Background: In many K ϩ channels, gating requires flexing of inner helices at glycine residues wi... more Background: In many K ϩ channels, gating requires flexing of inner helices at glycine residues within a "hinge motif." An analogous motif is present in the ryanodine receptor channel. Results: Mutation of ryanodine receptor "hinge" glycines produces varying effects on gating. Conclusion: Ryanodine receptors do not contain a typical glycine hinge. Significance: This work provides new insights into mechanisms of ryanodine receptor function. Ryanodine receptor channels (RyR) are key components of striated muscle excitation-contraction coupling, and alterations in their function underlie both inherited and acquired disease. A full understanding of the disease process will require a detailed knowledge of the mechanisms and structures involved in RyR function. Unfortunately, high-resolution structural data, such as exist for K ؉-selective channels, are not available for RyR. In the absence of these data, we have used modeling to identify similarities in the structural elements of K ؉ channel pore-forming regions and postulated equivalent regions of RyR. This has identified a sequence of residues in the cytosolic cavity-lining transmembrane helix of RyR (G 4864 LIIDA 4869 in RyR2) analogous to the glycine hinge motif present in many K ؉ channels. Gating in these K ؉ channels can be disrupted by substitution of residues for the hinge glycine. We investigated the involvement of glycine 4864 in RyR2 gating by monitoring properties of recombinant human RyR2 channels in which this glycine is replaced by residues that alter gating in K ؉ channels. Our data demonstrate that introducing alanine at position 4864 produces no significant change in RyR2 function. In contrast, function is altered when glycine 4864 is replaced by either valine or proline, the former preventing channel opening and the latter modifying both ion translocation and gating. Our studies reveal novel information on the structural basis of RyR gating, identifying both similarities with, and differences from, K ؉ channels. Glycine 4864 is not absolutely required for channel gating, but some flexibility at this point in the cavity-lining transmembrane helix is necessary for normal RyR function.
Criteria for inclusion in the Health Technology Assessment journal Reports are published in Healt... more Criteria for inclusion in the Health Technology Assessment journal Reports are published in Health Technology Assessment (HTA) if (1) they have resulted from work for the HTA programme, and (2) they are of a sufficiently high scientific quality as assessed by the reviewers and editors. Reviews in Health Technology Assessment are termed 'systematic' when the account of the search appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.
Interactions between a membrane protein and the lipid molecules that surround it in the membrane ... more Interactions between a membrane protein and the lipid molecules that surround it in the membrane are important in determining the structure and function of the protein. These interactions can be pictured at the molecular level using fluorescence spectroscopy, making use of the ability to introduce tryptophan residues into regions of interest in bacterial membrane proteins. Fluorescence quenching methods have been developed to study lipid binding separately on the two sides of the membrane. Lipid binding to the surface of the mechanosensitive channel MscL is heterogeneous, with a hot-spot for binding anionic lipid on the cytoplasmic side, associated with a cluster of three positively charged residues. The environmental sensitivity of tryptophan fluorescence emission has been used to identify the residues at the ends of the hydrophobic core of the second transmembrane α-helix in MscL. The efficiency of hydrophobic matching between MscL and the surrounding lipid bilayer is high. Fluore...
IntroductionSepsis is a common, potentially life-threatening complication of infection. The optim... more IntroductionSepsis is a common, potentially life-threatening complication of infection. The optimal treatment for sepsis includes prompt antibiotics and intravenous fluids, facilitated by its early and accurate recognition. Currently, clinicians identify and assess severity of suspected sepsis using validated clinical scoring systems. In England, the National Early Warning Score 2 (NEWS2) has been mandated across all National Health Service (NHS) trusts and ambulance organisations. Like many clinical scoring systems, NEWS2 should not be used without clinical judgement to determine either the level of acuity or a diagnosis. Despite this, there is a tendency to overemphasise the score in isolation in patients with suspected infection, leading to the overprescription of antibiotics and potentially treatment-related complications and rising antimicrobial resistance. The biomarker procalcitonin (PCT) has been shown to be useful in specific circumstances to support appropriate antibiotics...
Background Less than 10% of hospitalized cases in the United Kingdom during the first wave of the... more Background Less than 10% of hospitalized cases in the United Kingdom during the first wave of the pandemic had bacterial coinfection, but approximately 75% were prescribed antibiotics contrary to NICE guidelines. We have evaluated the relationship between antibiotic prescribing and biomarker use, in hospitalized adult patients with COVID-19 in the UK, as synthesis defined by the pandemic timeline, particularly during ‘Wave 2’ is lacking. Clinical outcomes were compared in the context of antimicrobial stewardship. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT) and white cell count (WCC) were selected based on clinical relevance. Methods Studies (n = 300) dated 2019–22 were identified via EMBASE and Web of Science databases, using relevant search terms. Wave 1 and Wave 2 parameters were defined by the Office for National Statistics. Literature selection was organized by the preferred reporting items for systematic reviews and meta-analyses (PRISMA)...
559-Pos Board B314 The Cardiac Ryanodine Receptor (RyR2): Investigating Mechanisms of Gating at t... more 559-Pos Board B314 The Cardiac Ryanodine Receptor (RyR2): Investigating Mechanisms of Gating at the Selectivity Filter Jahn M. Firth, Joanne Euden, Alan J. Williams. Institute of Molecular and Experimental Medicine, Cardiff, United Kingdom. Ryanodine receptors (RyR) provide the pathway for release of intracellular calcium ions (Ca2þ) that initiate muscle contraction. Mutations in cardiac RyRs, (RyR2) underlie arrhythmia and sudden cardiac death. RyRs are therefore an attractive therapeutic target, howevermore information regarding structure and function is required.The enormoussizeofRyRsprecludes detailed structural analysis. Models, based on potassium channel templates, exist for the RyR poreforming region (PFR) providing an invaluable framework in which predictions of specific processes of ion translocation and gating mechanisms can be tested. Potassium channels have a conserved gating mechanism involving a distinct hydrogen-bonding network of residues at the selectivity filter th...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus responsible for the... more Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus responsible for the coronavirus disease 2019 (COVID-19) pandemic. Although COVID-19 is a viral illness, many patients admitted to hospital are prescribed antibiotics, based on concerns that COVID-19 patients may experience secondary bacterial infections, and the assumption that they may respond well to antibiotic therapy. This has led to an increase in antibiotic use for some hospitalised patients at a time when accumulating antibiotic resistance is a major global threat to health. Procalcitonin (PCT) is an inflammatory marker measured in blood samples and widely recommended to help diagnose bacterial infections and guide antibiotic treatment. The PEACH study will compare patient outcomes from English and Welsh hospitals that used PCT testing during the first wave of the COVID-19 pandemic with those from hospitals not using PCT. It will help to determine whether, and how, PCT testing should be used in the ...
<p>(A) The logarithm of the molecular weight was plotted against elution volumes for three ... more <p>(A) The logarithm of the molecular weight was plotted against elution volumes for three protein standards: (a) B-amylase (200 kDa), (b) carbonic anhydrase (29 kDa) and (c) cytochrome c (12.4 kDa) to create a calibration curve. The expected elution position of the hRyR2-PFR is shown as a dotted line. (B) Gel filtration trace of analytical standards.</p
<p>(A) shows Po of hRyR2-PFR at −60 mV with neomycin added to both sides of the channel. (B... more <p>(A) shows Po of hRyR2-PFR at −60 mV with neomycin added to both sides of the channel. (B) shows Po of hRyR2-PFR at +60 mV under the same conditions. Data are plotted as mean ±S.E.M for between three and six channels. Where differences between the means reach statistical significance, these are indicated by asterisks (**P<0.005).</p
<p>(A) Gel filtration trace of hRyR2-PFR showing void volume; and protein peak; (PFR) at 72... more <p>(A) Gel filtration trace of hRyR2-PFR showing void volume; and protein peak; (PFR) at 72 mls as predicted by analytical gel filtration. (B) Purification samples of hRyR2-PFR 1-Load, 2-affinity sample, 3-void, 4-main peak, 5-second affinity sample following GF.</p
<p>A plot of open probability (Po) plotted against voltage is shown in symmetrical 210 mM K... more <p>A plot of open probability (Po) plotted against voltage is shown in symmetrical 210 mM KCl. All points are mean values ±SD derived from three or more experiments. Error bars, where not visible, are within the symbol. The cartoon inset shows a stylized representation of a typical section of recording from a bilayer containing 3 hRyR2-PFR channels at −80 mV. The collective open probability of these channels (Po<sub>(N)</sub>) was determined as the time spent at level N (level 3 in this example), as a proportion of the total time of the recording using QuB, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066542#s2" target="_blank">Materials and Methods</a>.</p
<p>(A) Current voltage plots of hRyR2-PFR in symmetrical 210 mM (•), 610 mM (▴), and 810 mM... more <p>(A) Current voltage plots of hRyR2-PFR in symmetrical 210 mM (•), 610 mM (▴), and 810 mM (⧫) KCl. Solid lines are derived from linear regression to give the slope conductance. All points are mean values ±SE derived from four or more experiments. Error bars, where not visible, are within the symbol. (B) shows the change in slope conductance with an increase in K<sup>+</sup> concentration for WT hRyR2 (▴) and the PFR (•). Lines are nonlinear regression derived from a single-site binding hyperbola. All points are mean values ±SE derived from four or more experiments. Error bars are within the symbol.</p
<p>(A) shows recordings at −40 mV with closings shown as downward deflections. P<sub>... more <p>(A) shows recordings at −40 mV with closings shown as downward deflections. P<sub>o</sub> is extremely high with very rare closing events. Closings are often too short to be fully resolved. (B) shows recordings at −80 mV. Closings occur more frequently and dwell times within closed states are much longer. Closed levels are denoted by C with the hashed line representing the closed level.</p
<p>(A) The pore forming region of KcsA and (B) our analogy model for the pore forming regio... more <p>(A) The pore forming region of KcsA and (B) our analogy model for the pore forming region of RyR2, constructed using KcsA as a template. Two monomers are shown for clarity as PyMOL cartoon representations (DeLano Scientific LLC, CA, USA).</p
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Papers by Joanne Euden