Cost-effectiveness analysis of Manuka honey-Omega-3 combination treatments in treating oxidative stress of pediatric β-thalassemia major

OBJECTIVE

Oxidative stress represents a ruthless complication of β-thalassemia that worsens the severity of that medical condition. There is no conclusive evidence on the best antioxidant used for that issue. Our earlier clinical study concluded that omega-3 and Manuka honey add-on to the conventional therapy had a potential therapeutic impact on reducing oxidative stress. However, there is no research evaluating their cost-effectiveness. This paper compares the cost-effectiveness of Omega-3 and Manuka honey supplementation to conventional therapy in treating oxidative stress among children with β-thalassemia major.

SUBJECTS AND METHODS

Cost-effectiveness evaluation of daily supplementation of Omega-3-Manuka honey and Manuka honey alone to the conventional therapy was performed. The economic evaluation was performed on data from a prospective 10-month randomized clinical trial. Fifty patients were recruited into the Omega-3-Manuka honey plus conventional therapy group, 50 patients were included in the Manuka honey alone plus conventional therapy group, and 50 patients receiving the conventional therapy alone served as a control group. Effectiveness measures from the randomized clinical trial were used to determine incremental effectiveness. Cost estimates were calculated from the healthcare payer's perspective. The analysis considered the improvement in oxidative stress biomarkers presented here as a percent change from baseline to determine the incremental effectiveness and cost for the treatment by both interventions.

RESULTS

Adding Omega-3 or Manuka honey to conventional therapy was a more cost-effective add-on than conventional treatment alone. Omega-3-Manuka honey was more cost-effective than Manuka honey alone in treating oxidative stress in that condition. Oxidative stress biomarkers were significantly reduced with both experimental medications compared to the conventional therapy alone.

CONCLUSIONS

The present study showed that using Manuka honey and Omega-3 as add-on treatments for oxidative stress in pediatric β-thalassemia disease could have significant cost-saving and clinical improvement.

Going around the Kok cycle of the water oxidation reaction with femtosecond X-ray crystallography

The water oxidation reaction in photosystem II (PS II) produces most of the molecular oxygen in the atmosphere, which sustains life on Earth, and in this process releases four electrons and four protons that drive the downstream process of CO2 fixation in the photosynthetic apparatus. The catalytic center of PS II is an oxygen-bridged Mn4Ca complex (Mn4CaO5) which is progressively oxidized upon the absorption of light by the chlorophyll of the PS II reaction center, and the accumulation of four oxidative equivalents in the catalytic center results in the oxidation of two waters to dioxygen in the last step. The recent emergence of X-ray free-electron lasers (XFELs) with intense femtosecond X-ray pulses has opened up opportunities to visualize this reaction in PS II as it proceeds through the catalytic cycle. In this review, we summarize our recent studies of the catalytic reaction in PS II by following the structural changes along the reaction pathway via room-temperature X-ray crystallography using XFELs. The evolution of the electron density changes at the Mn complex reveals notable structural changes, including the insertion of OX from a new water molecule, which disappears on completion of the reaction, implicating it in the O-O bond formation reaction. We were also able to follow the structural dynamics of the protein coordinating with the catalytic complex and of channels within the protein that are important for substrate and product transport, revealing well orchestrated conformational changes in response to the electronic changes at the Mn4Ca cluster.

Evolutionary diversity of proton and water channels on the oxidizing side of photosystem II and their relevance to function

One of the reasons for the high efficiency and selectivity of biological catalysts arise from their ability to control the pathways of substrates and products using protein channels, and by modulating the transport in the channels using the interaction with the protein residues and the water/hydrogen-bonding network. This process is clearly demonstrated in Photosystem II (PS II), where its light-driven water oxidation reaction catalyzed by the Mn4CaO5 cluster occurs deep inside the protein complex and thus requires the transport of two water molecules to and four protons from the metal center to the bulk water. Based on the recent advances in structural studies of PS II from X-ray crystallography and cryo-electron microscopy, in this review we compare the channels that have been proposed to facilitate this mass transport in cyanobacteria, red and green algae, diatoms, and higher plants. The three major channels (O1, O4, and Cl1 channels) are present in all species investigated; however, some differences exist in the reported structures that arise from the different composition and arrangement of membrane extrinsic subunits between the species. Among the three channels, the Cl1 channel, including the proton gate, is the most conserved among all photosynthetic species. We also found at least one branch for the O1 channel in all organisms, extending all the way from Ca/O1 via the 'water wheel' to the lumen. However, the extending path after the water wheel varies between most species. The O4 channel is, like the Cl1 channel, highly conserved among all species while having different orientations at the end of the path near the bulk. The comparison suggests that the previously proposed functionality of the channels in T. vestitus (Ibrahim et al., Proc Natl Acad Sci USA 117:12624-12635, 2020; Hussein et al., Nat Commun 12:6531, 2021) is conserved through the species, i.e. the O1-like channel is used for substrate water intake, and the tighter Cl1 and O4 channels for proton release. The comparison does not eliminate the potential role of O4 channel as a water intake channel. However, the highly ordered hydrogen-bonded water wire connected to the Mn4CaO5 cluster via the O4 may strongly suggest that it functions in proton release, especially during the S0 → S1 transition (Saito et al., Nat Commun 6:8488, 2015; Kern et al., Nature 563:421-425, 2018; Ibrahim et al., Proc Natl Acad Sci USA 117:12624-12635, 2020; Sakashita et al., Phys Chem Chem Phys 22:15831-15841, 2020; Hussein et al., Nat Commun 12:6531, 2021).

Comparative effectiveness of adding omega-3 and Manuka honey combination to conventional therapy in preventing and treating oxidative stress in pediatric β-thalassemia major - a randomized clinical trial

OBJECTIVE

β-thalassemia major is an inherited hematological disorder with significant oxidative stress and iron overload. Oxidative stress results in several pathological complications, including cell death, tissue injury, organ dysfunction, and thyroid dysfunction. The present study examined the effectiveness of omega-3 and Manuka honey combination or Manuka honey alone to the conventional therapy (deferasirox, blood transfusion, and L-carnitine) used for preventing and managing oxidative stress or iron overload-induced oxidative stress conditions in pediatric β-thalassemic patients (type major).

PATIENTS AND METHODS

165 patients participated in this randomized, double-blind, standard therapy-controlled, parallel-design multisite trial. The patients were randomly allocated into three groups, receiving either 1,000 mg omega-3 fish oil [350 mg eicosapentaenoic acid (EPA) and 250 mg docosahexaenoic acid (DHA)] combined with Manuka honey lozenge (344 mg) daily or Manuka honey alone plus the conventional therapy for ten months. Plasma 8-iso-prostaglandin F2α (8-iso-PGF2α), Lactate dehydrogenase (LDH), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), CRP (C-reactive protein), ferritin level, and serum iron were determined at baseline and month 10.

RESULTS

Omega-3 and Manuka honey combination were a significant add-on to conventional therapy of β-thalassemia in reducing the oxidative stress condition. The combination of Omega-3 and Manuka honey reduced the level of F2-isoprostane(8-iso-PGF2α) significantly compared to the Manuka alone and the control groups. Additionally, they showed an antihemolytic action measured by reduced LDH level. The combination restored the patient's lipid profile (LDL-C and HDL-C) significantly compared to the control group. Manuka honey enhanced the action of omega-3 in reducing oxidative stress by reducing serum iron significantly compared to the control group.

CONCLUSIONS

Results showed that omega-3 + Manuka honey was more effective than Manuka alone or the conventional treatment alone in managing oxidative stress of β-thalassemic patients.

Structural evidence for intermediates during O2 formation in photosystem II

In natural photosynthesis, the light-driven splitting of water into electrons, protons and molecular oxygen forms the first step of the solar-to-chemical energy conversion process. The reaction takes place in photosystem II, where the Mn4CaO5 cluster first stores four oxidizing equivalents, the S0 to S4 intermediate states in the Kok cycle, sequentially generated by photochemical charge separations in the reaction center and then catalyzes the O-O bond formation chemistry1-3. Here, we report room temperature snapshots by serial femtosecond X-ray crystallography to provide structural insights into the final reaction step of Kok's photosynthetic water oxidation cycle, the S3→[S4]→S0 transition where O2 is formed and Kok's water oxidation clock is reset. Our data reveal a complex sequence of events, which occur over micro- to milliseconds, comprising changes at the Mn4CaO5 cluster, its ligands and water pathways as well as controlled proton release through the hydrogen-bonding network of the Cl1 channel. Importantly, the extra O atom Ox, which was introduced as a bridging ligand between Ca and Mn1 during the S2→S3 transition4-6, disappears or relocates in parallel with Yz reduction starting at approximately 700 μs after the third flash. The onset of O2 evolution, as indicated by the shortening of the Mn1-Mn4 distance, occurs at around 1,200 μs, signifying the presence of a reduced intermediate, possibly a bound peroxide.

Capturing the sequence of events during the water oxidation reaction in photosynthesis using XFELs

Ever since the discovery that Mn was required for oxygen evolution in plants by Pirson in 1937 and the period-four oscillation in flash-induced oxygen evolution by Joliot and Kok in the 1970s, understanding of this process has advanced enormously using state-of-the-art methods. The most recent in this series of innovative techniques was the introduction of X-ray free-electron lasers (XFELs) a decade ago, which led to another quantum leap in the understanding in this field, by enabling operando X-ray structural and X-ray spectroscopy studies at room temperature. This review summarizes the current understanding of the structure of Photosystem II (PS II) and its catalytic centre, the Mn4 CaO5 complex, in the intermediate Si (i = 0-4)-states of the Kok cycle, obtained using XFELs.

A Survey Assessing Antimicrobial Prescribing at United Nations Relief and Works Agency Primary Health Care Centers in Jordan

Antimicrobial resistance (AMR) is a public health emergency. There is insufficient information on AMR in the context of humanitarian settings. An understanding of behavioral and institutional-level factors can strengthen antimicrobial stewardship. This study used a semistructured questionnaire to assess both knowledge, attitudes, and practices (KAP) on antimicrobial use, resistance and stewardship, and options to improving prescribing, among prescribers at the Primary Healthcare facilities of the United Nations' Relief and Works Agency Jordan field office. Responses to the KAP questions were evaluated using the Capability, Opportunity, Motivation, Behavior (COM-B) framework and Bloom's cutoffs. For each framework component, Bloom's cutoffs and interpretations were as follows: ≥ 80%, "good"; 60-79%, "moderate"; and < 60%, "poor." Fourteen options to improve prescribing were each assessed using 5-point Likert scales from very unhelpful to very helpful, aggregated by helpful and very helpful and ranked as follows: > 90%, best/most acceptable; > 80-90%, acceptable; and 70-80% as maybe acceptable/good. The questionnaire response rate was 59% (37/63) with a completion rate of 92% (34/37). Aggregate scores for real knowledge on AMR was 97%; opportunity to improve prescribing 88%; and motivation 16%-participants did not believe that there was a connection between their prescribing and AMR or that they had a key role in helping control AMR. Good options (74% aggregate score) to improving prescribing were the availability of guidelines and resistance data. There was good knowledge of AMR and good opportunities, but poor motivation for rational prescribing or behavioral change. There is a clinical need for AMR data to promote rational antibiotic prescribing.

Structural dynamics in the water and proton channels of photosystem II during the S2 to S3 transition

Light-driven oxidation of water to molecular oxygen is catalyzed by the oxygen-evolving complex (OEC) in Photosystem II (PS II). This multi-electron, multi-proton catalysis requires the transport of two water molecules to and four protons from the OEC. A high-resolution 1.89 Å structure obtained by averaging all the S states and refining the data of various time points during the S₂ to S₃ transition has provided better visualization of the potential pathways for substrate water insertion and proton release. Our results indicate that the O1 channel is the likely water intake pathway, and the Cl1 channel is the likely proton release pathway based on the structural rearrangements of water molecules and amino acid side chains along these channels. In particular in the Cl1 channel, we suggest that residue D1-E65 serves as a gate for proton transport by minimizing the back reaction. The results show that the water oxidation reaction at the OEC is well coordinated with the amino acid side chains and the H-bonding network over the entire length of the channels, which is essential in shuttling substrate waters and protons.

Room temperature XFEL crystallography reveals asymmetry in the vicinity of the two phylloquinones in photosystem I

Photosystem I (PS I) has a symmetric structure with two highly similar branches of pigments at the center that are involved in electron transfer, but shows very different efficiency along the two branches. We have determined the structure of cyanobacterial PS I at room temperature (RT) using femtosecond X-ray pulses from an X-ray free electron laser (XFEL) that shows a clear expansion of the entire protein complex in the direction of the membrane plane, when compared to previous cryogenic structures. This trend was observed by complementary datasets taken at multiple XFEL beamlines. In the RT structure of PS I, we also observe conformational differences between the two branches in the reaction center around the secondary electron acceptors A_1A and A_1B. The π-stacked Phe residues are rotated with a more parallel orientation in the A-branch and an almost perpendicular confirmation in the B-branch, and the symmetry breaking PsaB-Trp673 is tilted and further away from A_1A. These changes increase the asymmetry between the branches and may provide insights into the preferential directionality of electron transfer.

Effects of x-ray free-electron laser pulse intensity on the Mn K 1,3 x-ray emission spectrum in photosystem II-A case study for metalloprotein crystals and solutions

In the last ten years, x-ray free-electron lasers (XFELs) have been successfully employed to characterize metalloproteins at room temperature using various techniques including x-ray diffraction, scattering, and spectroscopy. The approach has been to outrun the radiation damage by using femtosecond (fs) x-ray pulses. An example of an important and damage sensitive active metal center is the Mn4CaO5 cluster in photosystem II (PS II), the catalytic site of photosynthetic water oxidation. The combination of serial femtosecond x-ray crystallography and Kβ x-ray emission spectroscopy (XES) has proven to be a powerful multimodal approach for simultaneously probing the overall protein structure and the electronic state of the Mn4CaO5 cluster throughout the catalytic (Kok) cycle. As the observed spectral changes in the Mn4CaO5 cluster are very subtle, it is critical to consider the potential effects of the intense XFEL pulses on the Kβ XES signal. We report here a systematic study of the effects of XFEL peak power, beam focus, and dose on the Mn Kβ1,3 XES spectra in PS II over a wide range of pulse parameters collected over seven different experimental runs using both microcrystal and solution PS II samples. Our findings show that for beam intensities ranging from ∼5 × 1015 to 5 × 1017 W/cm2 at a pulse length of ∼35 fs, the spectral effects are small compared to those observed between S-states in the Kok cycle. Our results provide a benchmark for other XFEL-based XES studies on metalloproteins, confirming the viability of this approach.

Lung Transplantation in COVID 19 ARDS - Short Term Outcomes

Introduction

COVID-19 associated severe acute respiratory syndrome rapidly progress to irreversible lung injury, multiple organ failure and death. Lung transplantation is considered as the rescue therapy for these patients. Herein, we reported a case series of two successful life-saving bilateral lung transplantations for COVID-19-associated respiratory failure.

Case Report

Case 1: A 69-year-old male was admitted for hypoxia and altered mental status. He was diagnosed with COVID-19 pneumonia by abnormal CT findings and positive PCR result. After receiving a course of dexamethasone, convalescent plasma, remdesivir and broad-spectrum antibiotics, he remained to be profoundly hypoxic, requiring non-invasive ventilation. Following two negative PCR results, he underwent bilateral lung transplantation on day 57. He was discharged to rehab unit on postoperative day 26. No desaturation was observed with the 6-min walk test on 30-day follow-up.

Case 2: A 63-year-old male was presented with cough, and dyspnea. He was hemodynamically stable, SpO2 was 94%, chest x-ray was normal and tested positive for COVID-19. He was discharged home with dexamethasone and bronchodilators. However, he presented back on day 6 with worsening dyspnea. He was admitted and received a course of dexamethasone, remdesivir, convalescent plasma and broad-spectrum antibiotics. Due to persistent hypoxic respiratory failure, the patient underwent bilateral orthotopic lung transplantation on day 68. His postoperative course was complicated by primary graft dysfunction stage 3 and required open tracheostomy. His condition gradually improved and decannulated. He is currently on room air and able to walk 30 ft using a roller walker.

Summary

SARS-CoV-2 recovery is characterized by post inflammatory fibrosis and multi organ dysfunction. Lung transplantation can be successfully performed in patients with final stage respiratory failure of COVID-19 related pulmonary fibrosis.

Solution Structure of the Detergent-Photosystem II Core Complex Investigated by Small-Angle Scattering Techniques

Albeit achieving the X-ray diffraction structure of dimeric photosystem II core complexes (dPSIIcc) at the atomic resolution, the nature of the detergent belt surrounding dPSIIcc remains ambiguous. Therefore, the solution structure of the whole detergent-protein complex of dPSIIcc of Thermosynechococcus elongatus (T. elongatus) solubilized in n-dodecyl-ß-d-maltoside (ßDM) was investigated by a combination of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) with contrast variation. First, the structure of dPSIIcc was studied separately in SANS experiments using a contrast of 5% D₂O. Guinier analysis reveals that the dPSIIcc solution is virtually free of aggregation in the studied concentration range of 2-10 mg/mL dPSIIcc, and characterized by a radius of gyration of 62 Å. A structure reconstitution shows that dPSIIcc in buffer solution widely retains the crystal structure reported by X-ray free electron laser studies at room temperature with a slight expansion of the entire protein. Additional SANS experiments on dPSIIcc samples in a buffer solution containing 75% D₂O provide information about the size and shape of the whole detergent-dPSIIcc. The maximum position of P(r) function increases to 68 Å, i.e., it is about 6 Å larger than that of dPSIIcc only, thus indicating the presence of an additional structure. Thus, it can be concluded that dPSIIcc is surrounded by a monomolecular belt of detergent molecules under appropriate solubilization conditions. The homogeneity of the ßDM-dPSIIcc solutions was also verified using dynamic light scattering. Complementary SAXS experiments indicate the presence of unbound detergent micelles by a separate peak consistent with a spherical shape possessing a radius of about 40 Å. The latter structure also contributes to the SANS data but rather broadens the SANS curve artificially. Without the simultaneous inspection of SANS and SAXS data, this effect may lead to an apparent underestimation of the size of the PS II-detergent complex. The formation of larger unbound detergent aggregates in solution prior to crystallization may have a significant effect on the crystal formation or quality of the ßDM-dPSIIcc.

Untangling the sequence of events during the S2 → S3 transition in photosystem II and implications for the water oxidation mechanism

In oxygenic photosynthesis, light-driven oxidation of water to molecular oxygen is carried out by the oxygen-evolving complex (OEC) in photosystem II (PS II). Recently, we reported the room-temperature structures of PS II in the four (semi)stable S-states, S1, S2, S3, and S0, showing that a water molecule is inserted during the S2 → S3 transition, as a new bridging O(H)-ligand between Mn1 and Ca. To understand the sequence of events leading to the formation of this last stable intermediate state before O2 formation, we recorded diffraction and Mn X-ray emission spectroscopy (XES) data at several time points during the S2 → S3 transition. At the electron acceptor site, changes due to the two-electron redox chemistry at the quinones, QA and QB, are observed. At the donor site, tyrosine YZ and His190 H-bonded to it move by 50 µs after the second flash, and Glu189 moves away from Ca. This is followed by Mn1 and Mn4 moving apart, and the insertion of OX(H) at the open coordination site of Mn1. This water, possibly a ligand of Ca, could be supplied via a "water wheel"-like arrangement of five waters next to the OEC that is connected by a large channel to the bulk solvent. XES spectra show that Mn oxidation (τ of ∼350 µs) during the S2 → S3 transition mirrors the appearance of OX electron density. This indicates that the oxidation state change and the insertion of water as a bridging atom between Mn1 and Ca are highly correlated.

A pilot study of avelumab in Epstein-Barr virus-associated gastric cancer

TPS473

Background: Gastric Cancer (GC) is the third most common cause of cancer related deaths worldwide. The median overall survival of patients with stage 4 disease is approximately 1 year. Current accepted treatment approach with chemotherapy is applied with little consideration for known genetic or biologic heterogeneity. Whilst immune-based approaches in GC look promising it is clear that single-agent PD1/PDL1 inhibition benefit a minority. We must clarify a means of identifying prospectively those patients who may benefit from this treatment. A recent landmark paper by The Cancer Genome Atlas (TCGA) proposed a classification of GC into four subtypes: Epstein-Barr-virus (EBV)-positive, microsatellite instable (MSI), chromosomal instable (CI), and genomically stable (GS). Two of the four – EBV and MSI subtypes – are likely to be immunogenic and amenable to PD1/PDL1 inhibition. Recent advances have shown EBV-positive tumors to be infiltrated by lymphocytes and be enriched for PDL1. Methods: This single centre single-arm pilot study in gastric or junctional adenocarcinoma will explore the hypothesis that administering anti-PDL1 therapy (Avelumab) in a prospectively identified population enriched for potential responders will result in improved outcomes. The anticipated frequency of EBV associated-GC (c10%) means that approximately N = 100 patients will be screened to identify N = 10 participants. If a positive signal for efficacy is seen this will provide a basis for a larger, multicentre study. Previously treated Patients with confirmation of stage 4 EBV- positive gastric or oesophago-gastric adenocarcinoma meeting eligibility criteria will be enrolled. Avelumab will be administered at a dose of 10mg/kg IV every 14days. Primary endpoint is to determine the 6-month progression free survival (PFS) of Avelumab in EBV-associated GC. Secondary endpoints include overall response rate, overall survival, median PFS time and feasibility/accrual rate at 12 months. Exploratory endpoints will be to evaluate changes in immune parameters in the peripheral blood over time. Kaplan-Meier methods for primary efficacy endpoint with two-tailed one-sample proportion test will be used to evaluate the evidence to reject the null hypothesis. Clinical trial information: 2018-002085-39.

Extending electron paramagnetic resonance to nanoliter volume protein single crystals using a self-resonant microhelix

Electron paramagnetic resonance (EPR) spectroscopy on protein single crystals is the ultimate method for determining the electronic structure of paramagnetic intermediates at the active site of an enzyme and relating the magnetic tensor to a molecular structure. However, crystals of dimensions typical for protein crystallography (0.05 to 0.3mm) provide insufficient signal intensity. In this work, we present a microwave self-resonant microhelix for nanoliter samples that can be implemented in a commercial X-band (9.5 GHz) EPR spectrometer. The self-resonant microhelix provides a measured signal-to-noise improvement up to a factor of 28 with respect to commercial EPR resonators. This work opens up the possibility to use advanced EPR techniques for studying protein single crystals of dimensions typical for x-ray crystallography. The technique is demonstrated by EPR experiments on single crystal [FeFe]-hydrogenase (Clostridium pasteurianum; CpI) with dimensions of 0.3 mm by 0.1 mm by 0.1 mm, yielding a proposed g-tensor orientation of the H_ox state.

Structures of the intermediates of Kok's photosynthetic water oxidation clock

Inspired by the period-four oscillation in flash-induced oxygen evolution of photosystem II discovered by Joliot in 1969, Kok performed additional experiments and proposed a five-state kinetic model for photosynthetic oxygen evolution, known as Kok's S-state clock or cycle^1,2. The model comprises four (meta)stable intermediates (S₀, S₁, S₂ and S₃) and one transient S₄ state, which precedes dioxygen formation occurring in a concerted reaction from two water-derived oxygens bound at an oxo-bridged tetra manganese calcium (Mn₄CaO₅) cluster in the oxygen-evolving complex^3-7. This reaction is coupled to the two-step reduction and protonation of the mobile plastoquinone Q_B at the acceptor side of PSII. Here, using serial femtosecond X-ray crystallography and simultaneous X-ray emission spectroscopy with multi-flash visible laser excitation at room temperature, we visualize all (meta)stable states of Kok's cycle as high-resolution structures (2.04-2.08 Å). In addition, we report structures of two transient states at 150 and 400 µs, revealing notable structural changes including the binding of one additional 'water', Ox, during the S₂→S₃ state transition. Our results suggest that one water ligand to calcium (W3) is directly involved in substrate delivery. The binding of the additional oxygen Ox in the S₃ state between Ca and Mn1 supports O-O bond formation mechanisms involving O5 as one substrate, where Ox is either the other substrate oxygen or is perfectly positioned to refill the O5 position during O₂ release. Thus, our results exclude peroxo-bond formation in the S₃ state, and the nucleophilic attack of W3 onto W2 is unlikely.

Discussion of “Evidence-based Health Informatics: How Do We Know What We Know?”

This article is part of a For-Discussion-Section of Methods of Information in Medicine about the paper “Evidence-based Health Informatics: How Do We Know What We Know?” written by Elske Ammenwerth [1]. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the Ammenwerth paper. In subsequent issues the discussion can continue through letters to the editor.

With these comments on the paper “Evidence-based Health Informatics: How do we know what we know?”, written by Elske Ammenwerth [1], the journal seeks to stimulate a broad discussion on the challenges of evaluating information processing and information technology in health care. An international group of experts has been invited by the editor of Methods to comment on this paper. Each of the invited commentaries forms one section of this paper.

Discussion of “Biomedical Infor -matics: We Are What We Publish”

This article is part of a For-Discussion-Section of Methods of Information in Medicine about the paper "Biomedical Informatics: We Are What We Publish", written by Peter L. Elkin, Steven H. Brown, and Graham Wright. It is introduced by an editorial. This article contains the combined commenta -ries invited to independently comment on the Elkin et al. paper. In subsequent issues the discussion can continue through letters to the editor.

Optimizing Crystal Size of Photosystem II by Macroseeding: Toward Neutron Protein Crystallography

Photosystem II (PSII) catalyzes the photo-oxidation of water to molecular oxygen and protons. The water splitting reaction occurs inside the oxygen-evolving complex (OEC) via a Mn₄CaO₅ cluster. To elucidate the reaction mechanism, detailed structural information for each intermediate state of the OEC is required. Despite the current high-resolution crystal structure of PSII at 1.85 Å and other efforts to follow the structural changes of the Mn₄CaO₅ cluster using X-ray free electron laser (XFEL) crystallography in addition to spectroscopic methods, many details about the reaction mechanism and conformational changes in the catalytic site during water oxidation still remain elusive. In this study, we present a rarely found successful application of the conventional macroseeding method to a large membrane protein like the dimeric PSII core complex (dPSIIcc). Combining microseeding with macroseeding crystallization techniques allowed us to reproducibly grow large dPSIIcc crystals with a size of ~3 mm. These large crystals will help improve the data collected from spectroscopic methods like polarized extended X-ray absorption fine structure (EXAFS) and single crystal electron paramagnetic resonance (EPR) techniques and are a prerequisite for determining a three-dimensional structure using neutron diffraction.

Structural insights into the light-driven auto-assembly process of the water-oxidizing Mn4CaO5-cluster in photosystem II

In plants, algae and cyanobacteria, Photosystem II (PSII) catalyzes the light-driven splitting of water at a protein-bound Mn₄CaO₅-cluster, the water-oxidizing complex (WOC). In the photosynthetic organisms, the light-driven formation of the WOC from dissolved metal ions is a key process because it is essential in both initial activation and continuous repair of PSII. Structural information is required for understanding of this chaperone-free metal-cluster assembly. For the first time, we obtained a structure of PSII from Thermosynechococcus elongatus without the Mn₄CaO₅-cluster. Surprisingly, cluster-removal leaves the positions of all coordinating amino acid residues and most nearby water molecules largely unaffected, resulting in a pre-organized ligand shell for kinetically competent and error-free photo-assembly of the Mn₄CaO₅-cluster. First experiments initiating (i) partial disassembly and (ii) partial re-assembly after complete depletion of the Mn₄CaO₅-cluster agree with a specific bi-manganese cluster, likely a di-µ-oxo bridged pair of Mn(III) ions, as an assembly intermediate.

DOI:http://dx.doi.org/10.7554/eLife.26933.001

Drop-on-demand sample delivery for studying biocatalysts in action at X-ray free-electron lasers

X-ray crystallography at X-ray free-electron laser sources is a powerful method for studying macromolecules at biologically relevant temperatures. Moreover, when combined with complementary techniques like X-ray emission spectroscopy, both global structures and chemical properties of metalloenzymes can be obtained concurrently, providing insights into the interplay between the protein structure and dynamics and the chemistry at an active site. The implementation of such a multimodal approach can be compromised by conflicting requirements to optimize each individual method. In particular, the method used for sample delivery greatly affects the data quality. We present here a robust way of delivering controlled sample amounts on demand using acoustic droplet ejection coupled with a conveyor belt drive that is optimized for crystallography and spectroscopy measurements of photochemical and chemical reactions over a wide range of time scales. Studies with photosystem II, the phytochrome photoreceptor, and ribonucleotide reductase R2 illustrate the power and versatility of this method.

Structure of photosystem II and substrate binding at room temperature

Light-induced oxidation of water by photosystem II (PS II) in plants, algae and cyanobacteria has generated most of the dioxygen in the atmosphere. PS II, a membrane-bound multi-subunit pigment protein complex, couples the one-electron photochemistry at the reaction centre with the four-electron redox chemistry of water oxidation at the Mn₄CaO₅ cluster in the oxygen-evolving complex (OEC). Under illumination, the OEC cycles through five intermediate S-states (S₀ to S₄), in which S₁ is the dark-stable state and S₃ is the last semi-stable state before O-O bond formation and O₂ evolution. A detailed understanding of the O-O bond formation mechanism remains a challenge, and will require elucidation of both the structures of the OEC in the different S-states and the binding of the two substrate waters to the catalytic site. Here we report the use of femtosecond pulses from an X-ray free electron laser (XFEL) to obtain damage-free, room temperature structures of dark-adapted (S₁), two-flash illuminated (2F; S₃-enriched), and ammonia-bound two-flash illuminated (2F-NH₃; S₃-enriched) PS II. Although the recent 1.95 Å resolution structure of PS II at cryogenic temperature using an XFEL provided a damage-free view of the S₁ state, measurements at room temperature are required to study the structural landscape of proteins under functional conditions, and also for in situ advancement of the S-states. To investigate the water-binding site(s), ammonia, a water analogue, has been used as a marker, as it binds to the Mn₄CaO₅ cluster in the S₂ and S₃ states. Since the ammonia-bound OEC is active, the ammonia-binding Mn site is not a substrate water site. This approach, together with a comparison of the native dark and 2F states, is used to discriminate between proposed O-O bond formation mechanisms.

Systematic analysis of protein-detergent complexes applying dynamic light scattering to optimize solutions for crystallization trials

Detergents are widely used for the isolation and solubilization of membrane proteins to support crystallization and structure determination. Detergents are amphiphilic molecules that form micelles once the characteristic critical micelle concentration (CMC) is achieved and can solubilize membrane proteins by the formation of micelles around them. The results are presented of a study of micelle formation observed by in situ dynamic light-scattering (DLS) analyses performed on selected detergent solutions using a newly designed advanced hardware device. DLS was initially applied in situ to detergent samples with a total volume of approximately 2 µl. When measured with DLS, pure detergents show a monodisperse radial distribution in water at concentrations exceeding the CMC. A series of all-trans n-alkyl-β-D-maltopyranosides, from n-hexyl to n-tetradecyl, were used in the investigations. The results obtained verify that the application of DLS in situ is capable of distinguishing differences in the hydrodynamic radii of micelles formed by detergents differing in length by only a single CH2 group in their aliphatic tails. Subsequently, DLS was applied to investigate the distribution of hydrodynamic radii of membrane proteins and selected water-insoluble proteins in presence of detergent micelles. The results confirm that stable protein-detergent complexes were prepared for (i) bacteriorhodopsin and (ii) FetA in complex with a ligand as examples of transmembrane proteins. A fusion of maltose-binding protein and the Duck hepatitis B virus X protein was added to this investigation as an example of a non-membrane-associated protein with low water solubility. The increased solubility of this protein in the presence of detergent could be monitored, as well as the progress of proteolytic cleavage to separate the fusion partners. This study demonstrates the potential of in situ DLS to optimize solutions of protein-detergent complexes for crystallization applications.

Discussion of "Biomedical informatics: we are what we publish"

This article is part of a For-Discussion-Section of Methods of Information in Medicine about the paper "Biomedical Informatics: We Are What We Publish", written by Peter L. Elkin, Steven H. Brown, and Graham Wright. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the Elkin et al. paper. In subsequent issues the discussion can continue through letters to the editor.

[Satisfaction with dental care from the patient's perspective - the dental-ZAP-V1]

BACKGROUND

Patient satisfaction is a central topic in quality management in outpatient dental care. The ZAP questionnaire was validated to explore patient satisfaction in general and specialist outpatient settings. This study aims at assessing the psychometric properties of the ZAP in dental care.

METHODS

A minimally modified version of the ZAP consisting of 4 domains (office organisation, cooperation, interaction, information) was administered in personal interviews to a population-based sample. Descriptive, exploratory and confirmatory psychometric analyses were conducted with random subsets of the study sample.

RESULTS

The study population comprised 1 773 subjects with at least one dental visit during their lifetime (mean age=50 years, female=51.6%). The exploratory factor analysis identified 3 subscales (office organisation, interaction, information). Based on these results, items of the subscale "cooperation" were excluded from further analyses. The remaining items had a medium difficulty of 0.75, all item-total-correlations were above 0.4. Missing values ranged between 2.3% and 28.7%. Cronbach's alpha ranged between 0.79 and 0.95. After introduction of 3 residual correlations, the confirmatory factor analyses reached a good model fit (TLI: 0.97; CFI: 0.97, RMSEA: 0.06). Partial standardised factor loadings ranged between 0.77 and 0.87. The 3 latent factors were highly correlated. There was a positive correlation between the 3 subscales and global patient satisfaction with the dentist.

CONCLUSION

The psychometric assessment can be used in the 3 modified subscales (office organisation, interaction, and information) to assess patient satisfaction with dental care. To assess dentist's competence in relation to dental anxiety and pain as well as shared decision making new scales specific to dental care should be explored.

Dying to give birth: the Pakistan Liaison Committee's strategies to improve maternal health in Pakistan

Pakistan has one of the worst maternal mortality ratios worldwide: 260-490 women die for every 100,000 live births in Pakistan. The Pakistan Liaison Group (PLG) was formed to work with and through the international office of the Royal College of Obstetricians and Gynaecologists (RCOG). It works with the RCOG representative committee in Pakistan to improve the health of women. It aims to contribute to improving maternal morbidity and mortality through strategies directed at improving the education and training of health professionals. In addition, the PLG aims to promote changes in the legislature to allow for the notification of maternal deaths so that accurate figures can be obtained, and so that health parameters can be accurately assessed and, in the long term, a confidential enquiry into maternal deaths can be initiated.

Biomedical and Health Informatics Education and Research at the Information Technology Institute in Egypt

During the last decade, Egypt has experienced a revolution in the field of Information and Communication Technology (ICT) that has had a corresponding impact on the field of healthcare.

Since 1993, the Information Technology Institute (ITI) has been leading the development of the Information Technology (IT) professional training and education in Egypt to produce top quality IT professionals who are considered now the backbone of the IT revolution in Egypt. For the past five years, ITI has been adopting the objective of building high caliber health professionals who can effectively serve the ever-growing information society.

Academic links have been established with internationally renowned universities, e.g., Oregon Health and Science University (OHSU) in US, University of Leipzig in Germany, in addition those with the Egyptian Fellowship Board in order to enrich ITI Medical Informatics Education and Research.

The ITI Biomedical and Health Informatics (BMHI) education and training programs target fresh graduates as well as lifelong learners. Therefore, the program’s learning objectives are framed within the context of the four specialization tracks: Healthcare Man- agement (HCM), Biomedical Informatics Research (BMIR), Bioinformatics Professional (BIP), and Healthcare Professional (HCP). The ITI BMHI research projects tackle a wide-range of current chal- lenges in this field, such as knowledge management in healthcare, providing tele-consultation services for diagnosis and treatment of infectious diseases for underserved regions in Egypt, and exploring the cultural and educational aspects of Nanoinformatics.

Since 2006, ITI has been positively contributing to de- velop the discipline of BMHI in Egypt in order to support improved healthcare services .

Biomedical and health informatics education and research at the Information Technology Institute in Egypt

OBJECTIVES

During the last decade, Egypt has experienced a revolution in the field of Information and Communication Technology (ICT) that has had a corresponding impact on the field of healthcare. Since 1993, the Information Technology Institute (ITI) has been leading the development of the Information Technology (IT) professional training and education in Egypt to produce top quality IT professionals who are considered now the backbone of the IT revolution in Egypt. For the past five years, ITI has been adopting the objective of building high caliber health professionals who can effectively serve the ever-growing information society.

METHODS

Academic links have been established with internationally renowned universities, e.g., Oregon Health and Science University (OHSU) in US, University of Leipzig in Germany, in addition those with the Egyptian Fellowship Board in order to enrich ITI Medical Informatics Education and Research.

RESULTS

The ITI Biomedical and Health Informatics (BMHI) education and training programs target fresh graduates as well as life-long learners. Therefore, the program's learning objectives are framed within the context of the four specialization tracks: Healthcare Management (HCM), Biomedical Informatics Research (BMIR), Bioinformatics Professional (BIP), and Healthcare Professional (HCP). The ITI BMHI research projects tackle a wide-range of current challenges in this field, such as knowledge management in healthcare, providing tele-consultation services for diagnosis and treatment of infectious diseases for underserved regions in Egypt, and exploring the cultural and educational aspects of Nanoinformatics.

CONCLUSION

Since 2006, ITI has been positively contributing to develop the discipline of BMHI in Egypt in order to support improved healthcare services.

A toxicological evaluation of inhaled solid lipid nanoparticles used as a potential drug delivery system for the lung

Inhalation is a non-invasive approach for both local and systemic drug delivery. This study aimed to define the therapeutic window for solid lipid nanoparticles (SLNs) as a drug delivery system by inhalation from a toxicological point of view. To estimate the toxic dose of SLNs in vitro, A549 cells and murine precision-cut lung slices (PCLS) were exposed to increasing concentrations of SLNs. The cytotoxic effect of SLNs on A549 cells was evaluated by MTT and NRU assays. Viability of lung tissue was determined with WST assay and by life/dead staining using calcein AM/EthD-1 for confocal microscopy (CLSM) followed by quantitative analysis with IMARIS. Inflammation was assessed by measuring chemokine KC and TNF-alpha levels. The in vivo effects were determined in a 16-day repeated-dose inhalation toxicity study using female BALB/c mice, which were daily exposed to different concentrations of SLN30 aerosols (1-200 microg deposit dose). Local inflammatory effects in the respiratory tract were evaluated by determination of total protein content, LDH, chemokine KC, IL-6, and differential cell counts, performed on days 4, 8, 12, and 16 in bronchoalveolar lavage fluid. Additionally, a histopathological evaluation of toxicologically relevant organs was accomplished. The in vitro and ex vivo dose finding experiments showed toxic effects beginning at concentrations of about 500 microg/ml. Therefore, we used 1-200 microg deposit doses/animal for the in vivo experiments. Even after 16 days of challenge with a 200-microg deposit dose, SLNs induced no significant signs of inflammation. We observed no consistent increase in LDH release, protein levels, or other signs of inflammation such as chemokine KC, IL-6, or neutrophilia. In contrast, the particle control (carbon black) caused inflammatory and cytotoxic effects at corresponding concentrations. These results confirm that repeated inhalation exposure to SLN30 at concentrations lower than a 200-microg deposit dose is safe in a murine inhalation model.

Evaluating wastewater-induced plant genotoxicity using randomly amplified polymorphic DNA

Wastewater often contains genotoxic substances that can resist different stages of the treatment process. In the present study, randomly amplified polymorphic DNA technology was applied to evaluate the genotoxic effects of wastewater (treated and raw) irrigation on oat plants (Avena sativa). RAPD profiles obtained showed that both treated and raw wastewater (RWW) were having genotoxic effects on oat plants. This was apparent by the appearance/disappearance of bands in the treatments compared with the control plants. From the 15 primers used, 186 bands were obtained with an average of 12.4 bands per primer. Irrigating plants with RWW caused 51 new bands to appear and 19 to disappear. Treated wastewater (TWW) caused only 16 new bands and the loss of 17 bands. This makes TWW less genotoxic than RWW. The Euclidean distances shown on the dendrogram, revealed the presence of two clusters according to dissimilarity values. One cluster contained the control plants and those irrigated with TWW, whereas the second contained the plants irrigated with RWW. Similarity indices calculated between the treatments and the control plants showed that the control and the plants irrigated with TWW had a similarity index of 0.87, the control and plants irrigated with RWW 0.73 and between the treatments 0.75.

Complex regional pain syndrome with special emphasis on the knee

Complex regional pain syndrome is characterised by an exaggerated response to injury in a limb with intense prolonged pain, vasomotor disturbance, delayed functional recovery and trophic changes. This review describes the current knowledge of the condition and outlines the methods of treatment available with particular emphasis on the knee.

Soft tissue sarcomas: are current referral guidelines sufficient?

INTRODUCTION

To investigate the adequacy of current early referral guidelines for patients with extremity soft tissue sarcomas.

PATIENTS & METHODS

365 patients with confirmed soft tissue sarcomas were evaluated. Data were collected prospectively and included the length of history and the presence of features in current guidelines suggestive of malignancy (pain, rapidity of growth, depth and tumour size). Statistical analysis included the t-test, ANOVA and the Chi test.

RESULTS

Deep tumours were the commonest (306 patients with deep tumours). Pain was the least consistent feature (176 patients with pain). 345 patients with one or more of the guideline features had an average history of 19.86 months, 238 of these were seen after more than 3 months.

CONCLUSION

Although the majority of soft tissue sarcomas in our patients had one or more of the clinical guideline features, there was still an unacceptable delay in referring these patients to a specialist unit. The referral guidelines should be modified with special emphasis on depth, which is the most sensitive, followed by size and a history of rapid growth. This combined with increased awareness of these guidelines and a well-advertised, open-access clinic linked to a specialist unit should allow for a more rapid evaluation of soft tissue tumours.