Magnetic sensitivity of cryptochrome 4 from a migratory songbird.

Night-migratory songbirds are remarkably proficient navigators1. Flying alone and often over great distances, they use various directional cues including, crucially, a light-dependent magnetic compass2,3. The mechanism of this compass has been suggested to rely on the quantum spin dynamics of photoinduced radical pairs in cryptochrome flavoproteins located in the retinas of the birds4-7. Here we show that the photochemistry of cryptochrome 4 (CRY4) from the night-migratory European robin (Erithacus rubecula) is magnetically sensitive in vitro, and more so than CRY4 from two non-migratory bird species, chicken (Gallus gallus) and pigeon (Columba livia). Site-specific mutations of ErCRY4 reveal the roles of four successive flavin-tryptophan radical pairs in generating magnetic field effects and in stabilizing potential signalling states in a way that could enable sensing and signalling functions to be independently optimized in night-migratory birds.

Magnetosome-inspired synthesis of soft ferrimagnetic nanoparticles for magnetic tumor targeting.

Magnetic targeting is one of the most promising approaches for improving the targeting efficiency by which magnetic drug carriers are directed using external magnetic fields to reach their targets. As a natural magnetic nanoparticle (MNP) of biological origin, the magnetosome is a special "organelle" formed by biomineralization in magnetotactic bacteria (MTB) and is essential for MTB magnetic navigation to respond to geomagnetic fields. The magnetic targeting of magnetosomes, however, can be hindered by the aggregation and precipitation of magnetosomes in water and biological fluid environments due to the strong magnetic attraction between particles. In this study, we constructed a magnetosome-like nanoreactor by introducing MTB Mms6 protein into a reverse micelle system. MNPs synthesized by thermal decomposition exhibit the same crystal morphology and magnetism (high saturation magnetization and low coercivity) as natural magnetosomes but have a smaller particle size. The DSPE-mPEG-coated magnetosome-like MNPs exhibit good monodispersion, penetrating the lesion area of a tumor mouse model to achieve magnetic enrichment by an order of magnitude more than in the control groups, demonstrating great prospects for biomedical magnetic targeting applications.

Tumor Microenvironment Activatable Nanoprodrug System for In Situ Fluorescence Imaging and Therapy of Liver Cancer.

The development of new imaging and treatment nanoprodrug systems is highly demanded for diagnosis and therapy of liver cancer, a severe disease characterized by a high recurrence rate. Currently, available small molecule drugs are not possible for cancer diagnosis because of the fast diffusion of imaging agents and low efficacy in treatment due to poor water solubility and significant toxic side effects. In this study, we report the development of a tumor microenvironment activatable nanoprodrug system for the diagnosis and treatment of liver cancer. This nanoprodrug system can accumulate in the tumor site and be selectively activated by an excess of hydrogen peroxide (H2O2) in the tumor microenvironment, releasing near-infrared solid-state organic fluorescent probe (HPQCY-1) and phenylboronic acid-modified camptothecin (CPT) prodrug. Both HPQCY-1 and CPT prodrugs can be further activated in tumor sites for achieving more precise in situ near-infrared (NIR) fluorescence imaging and treatment while reducing the toxic effects of drugs on normal tissues. Additionally, the incorporation of hydrophilic multivalent chitosan as a carrier effectively improved the water solubility of the system. This research thus provides a practical new approach for the diagnosis and treatment of liver cancer.

Activatable fluorescent probes for early diagnosis and evaluation of liver injury.

With the increase in people's living standards, the number of patients suffering from liver injury keeps on increasing. Traditional diagnostic methods can no longer meet the needs of early and accurate diagnosis due to their limitations in application. However, fluorescent probes based on different fluorophores and nanomaterials have been gradually lighting up medical research due to their unique properties, such as high specificity and non-invasiveness. In addition, accurate identification of the different types of liver injury biomarkers can significantly improve the level of early diagnosis. Therefore, this review reviews the fluorescent probes used in the detection of biomarkers of liver injury over recent years and briefly summarizes the corresponding biomarkers of different types of liver injury. Impressively, this review also lists the structures and the response mechanisms of the different probes, and concludes with an outlook, suggesting directions in which improvements can be made. Finally, we hope that this review will contribute to the further development of fluorescent probes for the early diagnosis and assessment of liver injury.

DZ2002 alleviates corneal angiogenesis and inflammation in rodent models of dry eye disease via regulating STAT3-PI3K-Akt-NF-κB pathway.

Dry eye disease (DED) is a prevalent ocular disorder with a multifactorial etiology. The pre-angiogenic and pre-inflammatory milieu of the ocular surface plays a critical role in its pathogenesis. DZ2002 is a reversible type III S-adenosyl-L-homocysteine hydrolase (SAHH) inhibitor, which has shown excellent anti-inflammatory and immunosuppressive activities in vivo and in vitro. In this study, we evaluated the therapeutic potential of DZ2002 in rodent models of DED. SCOP-induced dry eye models were established in female rats and mice, while BAC-induced dry eye model was established in female rats. DZ2002 was administered as eye drops (0.25%, 1%) four times daily (20 µL per eye) for 7 or 14 consecutive days. We showed that topical application of DZ2002 concentration-dependently reduced corneal neovascularization and corneal opacity, as well as alleviated conjunctival irritation in both DED models. Furthermore, we observed that DZ2002 treatment decreased the expression of genes associated with angiogenesis and the levels of inflammation in the cornea and conjunctiva. Moreover, DZ2002 treatment in the BAC-induced DED model abolished the activation of the STAT3-PI3K-Akt-NF-κB pathways in corneal tissues. We also found that DZ2002 significantly inhibited the proliferation, migration, and tube formation of human umbilical endothelial cells (HUVECs) while downregulating the activation of the STAT3-PI3K-Akt-NF-κB pathway. These results suggest that DZ2002 exerts a therapeutic effect on corneal angiogenesis in DED, potentially by preventing the upregulation of the STAT3-PI3K-Akt-NF-κB pathways. Collectively, DZ2002 is a promising candidate for ophthalmic therapy, particularly in treating DED.

Rationally Constructed De Novo Fluorescent Nanosensor for Nitric Oxide Detection and Imaging in Living Cells and Inflammatory Mice Models.

For the early diagnosis and effective evaluation of treatment effects of inflammation, a de novo bioanalytical method is urgently needed to monitor the metabolite nitric oxide (NO) associated with inflammatory diseases. However, developing a reliable detection method with excellent water solubility, biocompatibility, long retention time, and blood circulation is still challenging. In this work, we reported for the first time a de novo host-guest self-assembled nanosensor CTA for the quantitative detection and visualization of NO levels in inflammatory models. CTA mainly consists of two parts: (i) an adamantyl-labeled guest small-molecule RN-adH containing a classical response moiety o-phenylenediamine for a chemical-specific response toward NO and fluorophore rhodamine B with excellent optical properties as an internal reference for self-calibration and (ii) a remarkable water-soluble and biocompatible supramolecular ß-cyclodextrin polymer (Poly-ß-CD) host. In the presence of NO, the o-phenylenediamine unit was reacted with NO at a low pH value of ∼7.0, accompanied by changes in the intensity of the two emission peaks corrected for each other and the change in fluorescence color of the CTA solution from fuchsia to pink. Furthermore, CTA was an effective tool for NO detection with a fast response time (∼60 s), high selectivity, and sensitivity (LOD: 22.3 nM). Impressively, the CTA nanosensor has successfully achieved the targeted imaging of NO in living inflammatory RAW 264.7 cells and mice models with satisfactory results, which can provide a powerful molecular tool for the visualization and assessment of the occurrence and development of NO-related inflammatory diseases in complex biosystems.

[Prediction and analysis of Q-markers of Elephantopus scaber based on its UPLC fingerprint, content determination of components, and in vitro a nti-tumor activity].

This study aimed to provide scientific evidence for predicting quality markers(Q-markers) of Elephantopus scaber by establishing UPLC fingerprint of E. scaber from different geographical origins and determining the content of 13 major components, as well as conducting in vitro anti-cancer activity investigation of the main components. The chromatographic column used was Waters CORTECS UPLC C_(18)(2.1 mm×150 mm, 1.6 µm), and the mobile phase consisted of acetonitrile and 0.1% formic acid solution(gradient elution). The column temperature was set at 30 ℃, and the flow rate was 0.2 mL·min~(-1). The injection volume was 1 µL, and the detection wavelength was 240 nm. The UPLC fingerprint of E. scaber was fitted using the Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 edition) to determine common peaks, evaluate similarity, identify and determine the content of major components. The CCK-8 assay was used to explore the inhibitory effect of the main components on the proliferation of lung cancer cells. The results showed that in the established UPLC fingerprint of E. scaber, 35 common peaks were identified. Thirteen major components, including neochlorogenic acid(peak 1), chlorogenic acid(peak 2), cryptochlorogenic acid(peak 3), caffeic acid(peak 4), schaftoside(peak 6), galuteolin(peak 9), isochlorogenic acid B(peak 10), isochlorogenic acid A(peak 12), isochlorogenic acid C(peak 18), deoxyelephantopin(peak 28), isodeoxyelephantopin(peak 29), isoscabertopin(peak 31), and scabertopin(peak 32) were identified and quantified, and a quantitative analysis method was established. The results of the in vitro anti-cancer activity study showed that deoxyelephantopin, isodeoxyelephantopin, isoscabertopin, and scabertopin in E. scaber exhibited inhibition rates of lung cancer cell proliferation exceeding 80% at a concentration of 10 µmol·L~(-1), higher than the positive drug paclitaxel. These results indicate that the fingerprint of E. scaber is highly characteristic, and the quantitative analysis method is accurate and stable, providing references for the research on quality standards of E. scaber. Four sesquiterpene lactones in E. scaber show significant anti-cancer activity and can serve as Q-markers for E. scaber.

Activated Two-Photon Near-Infrared Ratiometric Fluorescent Nanoprobe for ONOO- Detection and Early Diagnosis and Assessment of Liver Injury.

Liver injury poses a serious threat to human health and growing evidence suggests that it is closely associated with a biomarker (peroxynitrite, ONOO-). Therefore, considering that the relationship of ONOO- levels with the occurrence and development of liver injury disease remains a challenge, an urgent need exists to develop a reliable and robust tool for its visual rapid diagnosis and assessment. Herein, a two-photon near-infrared (TP-NIR) ratiometric fluorescent nanoprobe (NTC) based on a fluorescence resonance energy transfer (FRET) strategy was designed, synthesized, and characterized, which had the advantages of good water solubility, low background interference, deep tissue penetration, and high imaging resolution. Specially, NTC was constructed by self-assembly of an alkynyl group of a small-molecule fluorescent probe (NR) via click chemistry grafting onto azide chitosan (natural polymeric nanomaterial). NR contained acceptor 1 (NIR fluorophore) and donor 3 (D-π-A structure of naphthalimide derivative fluorophore) with outstanding TP properties that could be activated by ONOO- for the ratiometric detection of ONOO-. Furthermore, in the presence of ONOO-, NTC exhibited a short response time (∼10 s) and high selectivity and sensitivity toward ONOO- with an excellent detection limit as low as 15.3 nM over other reactive oxygen/nitrogen species. Notably, NTC has been successfully employed for ONOO- detection and imaging in living HepG2 cells, liver injury mice tissues, and mice models with satisfactory results. Thus, the construction of this NTC nanoprobe can provide a robust molecule tool for enabling early diagnosis and assessment of liver injury in the future.

Pomegranate-Like KVPO4 F@C Microspheres as High-Volumetric-Energy-Density Cathode for Potassium-Ion Batteries.

KVPO4 F is one of the most competitive cathode candidates for potassium-ion batteries (KIBs) because of its high output voltage and energy density. Although the gravimetric energy density of KIBs is intensively discussed in literature, little attention is paid to the volumetric energy density. In view of this, pomegranate-like carbon-coated KVPO4 F microspheres with a high volumetric energy density are designed in this work. The nano-sized primary particles with carbon sheets in KVPO4 F microspheres enable promis rate capability by enhancing the K+ diffusion kinetics, while the micro-sized spheres guarantee the improvement of cycling stability. Owing to the dense hierarchical microspheres, the volumetric energy density of cells is greatly improved compared to bulk materials. This cathode delivers a reversible capacity of 101.5 mA h g-1 at 0.3 C with an average output voltage of 4.0 V and a capacity retention of 85.1% after 200 cycles. The KVPO4 F@C microspheres have a compact density of 2.45 g cm-3 and further offer a high volumetric energy density up to 891.3 Wh L-1 . The overcharge behavior of KVPO4 F in the first three cycles is also revealed. The presented KVPO4 F@C microspheres cathode provides a new sight for developing KIBs with large volumetric energy density.

A flexible-hazards cure model with application to patients with soft tissue sarcoma.

In medical research, it is often of great interest to have an accurate estimation of cure rates by different treatment options and for different patient groups. If the follow-up time is sufficiently long and the sample size is large, the proportion of cured patients will make the Kaplan-Meier estimator of survival function have a flat plateau at its tail, whose value indicates the overall cure rate. However, it may be difficult to estimate and compare the cure rates for all the subsets of interest in this way, due to the limit of sample sizes and curse of dimensionality. In the current literature, most regression models for estimating cure rates assume proportional hazards (PH) between different subgroups. It turns out that the estimation of cure rates for subgroups is highly sensitive to this assumption, so more flexible models are needed, especially when this PH assumption is clearly violated. We propose a new cure model to simultaneously incorporate both PH and non-PH scenarios for different covariates. We develop a stable and easily implementable iterative procedure for parameter estimation through maximization of the nonparametric likelihood function. The covariance matrix is estimated by adding perturbation weights to the estimation procedure. In simulation studies, the proposed method provides unbiased estimation for the regression coefficients, survival curves, and cure rates given covariates, while existing models are biased. Our model is applied to a study of stage III soft tissue sarcoma and provides trustworthy estimation of cure rates for different treatment and demographic groups.

Gut-derived fungemia due to Kodamaea ohmeri combined with invasive pulmonary aspergillosis: a case report.

BACKGROUND: Kodamaea ohmeri is a rare pathogen with high mortality and is found among blood samples in a considerable proportion; however, gastrointestinal infection of K. ohmeri is extremely rare. Invasive pulmonary aspergillosis is also an uncommon fungal; these two fungal infections reported concomitantly are unprecedented. CASE PRESENTATION: We described a case of a 37-year-old male who got infected with K. ohmeri and invasive pulmonary aspergillosis. We used the mass spectrometry and histopathology to identify these two fungal infections separately. For the treatment of K. ohmeri, we chose caspofungin. As for invasive pulmonary aspergillosis, we used voriconazole, amphotericin B, and then surgery. The patient was treated successfully through the collaboration of multiple disciplines. CONCLUSIONS: We speculate that the destruction of the intestinal mucosa barrier can make the intestine one of the ways for certain fungi to infect the human body.

A Rationally Designed Building Block of the Putative Magnetoreceptor MagR.

The ability of animals to perceive guidance cues from Earth's magnetic field for orientation and navigation has been supported by a wealth of behavioral experiments, yet the nature of this sensory modality remains fascinatingly unresolved and wide open for discovery. MagR has been proposed as a putative magnetoreceptor based on its intrinsic magnetism and its complexation with a previously suggested key protein in magnetosensing, cryptochrome, to form a rod-like polymer structure. Here, we report a rationally designed single-chain tetramer of MagR (SctMagR), serving as the building block of the hierarchical assembly of MagR polymer. The magnetic trapping experiment and direct magnetic measurement of SctMagR demonstrated the possibility of magnetization of nonmagnetic cells via overexpressing a single protein, which has great potential in various applications. SctMagR, as reported in this study, serves as a prototype of designed magnetic biomaterials inspired by animal magnetoreception. The features of SctMagR provide insights into the unresolved origin of the intrinsic magnetic moment, which is of considerable interest in both biology and physics. © 2022 Bioelectromagnetics Society.

A Review for In Vitro and In Vivo Detection and Imaging of Gaseous Signal Molecule Carbon Monoxide by Fluorescent Probes.

Carbon monoxide (CO) is a vital endogenous gaseous transmitter molecule involved in the regulation of various physiological and pathological processes in living biosystems. In order to investigate the biological function of CO, many technologies have been developed to monitor the level of endogenous CO in biosystems. Among them, the fluorescence detection technology based on the fluorescent probe has the advantages of high sensitivity, excellent selectivity, simple operation, especially non-invasive damage to biological samples, and the possibility of real-time in situ detection, etc., which is considered to be one of the most effective and applicable detection techniques. Therefore, in the last few years, a lot of work has been carried out on the design, synthesis and in vivo fluorescence imaging studies of CO fluorescent probes. Furthermore, using fluorescent probes to detect the changes in CO concentrations in living cells and tissues as well as in organisms has been one of the hot research topics in recent years. However, it is still a challenge to rationally design CO fluorescent probe with excellent optical performance, structural stability, low background interference, good biocompatibility, and excellent water solubility. Therefore, this review focuses on the research progress of CO fluorescent probes in the detection mechanism and biological applications in recent years. However, this popular and leading topic has rarely been summarized comprehensively to date. Thus, the research progress of CO fluorescent probes in recent years is reviewed in terms of their design concept, detection mechanism, and their biological applications. In addition, the relationship between the structure and performance of the probes was also discussed. More significantly, we hope that more excellent optical properties fluorescent probes for gaseous transmitter molecule CO detection and imaging will overcome the current problems of high biotoxicity and limited water solubility in future.

Reversible rearrangement of magnetic nanoparticles in solution studied using time-resolved SAXS method.

Superparamagnetic nanoparticles have broad applications in biology and medicines. Quantitative measurements of magnetic beads in solution are essential in gaining comprehensive understanding of their dynamics and developing applications. Here, using synchrotron X-ray sources combined with well controlled magnetic fields, the results from small-angle X-ray scattering (SAXS) experiments on superparamagnetic particles in solution under the influence of external magnetic fields are reported. The particles mostly remain in monodispersed states and the linear aggregates tend to be aligned with the external magnetic field. After removing the magnetic fields, the superparamagnetic nanoparticles quickly recover to their original states indicating high reversibility of the rearrangement under the control of a magnetic field. The external magnetic field instrument composed of paired permanent magnets is integrated into the SAXS beamline at the Shanghai Synchrotron Radiation Facility providing a platform for studying time-resolved dynamics induced by magnetic fields.

Fenobody: A Ferritin-Displayed Nanobody with High Apparent Affinity and Half-Life Extension.

Nanobodies consist of a single domain variable fragment of a camelid heavy-chain antibody. Nanobodies have potential applications in biomedical fields because of their simple production procedures and low cost. Occasionally, nanobody clones of interest exhibit low affinities for their target antigens, which, together with their short half-life limit bioanalytical or therapeutic applications. Here, we developed a novel platform we named fenobody, in which a nanobody developed against H5N1 virus is displayed on the surface of ferritin in the form of a 24mer. We constructed a fenobody by substituting the fifth helix of ferritin with the nanobody. TEM analysis showed that nanobodies were displayed on the surface of ferritin in the form of 6 × 4 bundles, and that these clustered nanobodies are flexible for antigen binding in spatial structure. Comparing fenobodies with conventional nanobodies currently used revealed that the antigen binding apparent affinity of anti-H5N1 fenobody was dramatically increased (∼360-fold). Crucially, their half-life extension in a murine model was 10-fold longer than anti-H5N1 nanobody. In addition, we found that our fenobodies are highly expressed in Escherichia coli, and are both soluble and thermo-stable nanocages that self-assemble as 24-polymers. In conclusion, our results demonstrate that fenobodies have unique advantages over currently available systems for apparent affinity enhancement and half-life extension of nanobodies. Our fenobody system presents a suitable platform for various large-scale biotechnological processes and should greatly facilitate the application of nanobody technology in these areas.

A magnetic protein biocompass.

The notion that animals can detect the Earth's magnetic field was once ridiculed, but is now well established. Yet the biological nature of such magnetosensing phenomenon remains unknown. Here, we report a putative magnetic receptor (Drosophila CG8198, here named MagR) and a multimeric magnetosensing rod-like protein complex, identified by theoretical postulation and genome-wide screening, and validated with cellular, biochemical, structural and biophysical methods. The magnetosensing complex consists of the identified putative magnetoreceptor and known magnetoreception-related photoreceptor cryptochromes (Cry), has the attributes of both Cry- and iron-based systems, and exhibits spontaneous alignment in magnetic fields, including that of the Earth. Such a protein complex may form the basis of magnetoreception in animals, and may lead to applications across multiple fields.

Opposing Control by Transcription Factors MYB61 and MYB3 Increases Freezing Tolerance by Relieving C-Repeat Binding Factor Suppression.

Cold acclimation is an important process by which plants respond to low temperature and enhance their winter hardiness. C-REPEAT BINDING FACTOR1 (CBF1), CBF2, and CBF3 genes were shown previously to participate in cold acclimation in Medicago truncatula In addition, MtCBF4 is transcriptionally induced by salt, drought, and cold stresses. We show here that MtCBF4, shown previously to enhance drought and salt tolerance, also positively regulates cold acclimation and freezing tolerance. To identify molecular factors acting upstream and downstream of the MtCBF4 transcription factor (TF) in cold responses, we first identified genes that are differentially regulated upon MtCBF4 overexpression using RNAseq Digital Gene Expression Profiling. Among these, we showed that MtCBF4 directly activates the transcription of the COLD ACCLIMATION SPECIFIC15 (MtCAS15) gene. To gain insights into how MtCBF4 is transcriptionally regulated in response to cold, an R2R3-MYB TF, MtMYB3, was identified based on a yeast one-hybrid screen as binding directly to MYB cis-elements in the MtCBF4 promoter, leading to the inhibition of MtCBF4 expression. In addition, another MYB TF, MtMYB61, identified as an interactor of MtMYB3, can relieve the inhibitory effect of MtMYB3 on MtCBF4 transcription. This study, therefore, supports a model describing how MtCBF4 is regulated by antagonistic MtMYB3/MtMYB61 TFs, leading to the up-regulation of downstream targets such as MtCAS15 acting in cold acclimation in M. truncatula.

Efficacy and tolerability of budesonide/formoterol added to tiotropium compared with tiotropium alone in patients with severe or very severe COPD: A randomized, multicentre study in East Asia.

BACKGROUND AND OBJECTIVE: Triple combination therapy with tiotropium plus budesonide/formoterol has improved lung function and reduced exacerbation risk in patients with chronic obstructive pulmonary disease (COPD) in Western countries, but no such data exist for East Asian patients. This study aimed to evaluate the efficacy and tolerability of adding budesonide/formoterol to tiotropium compared with tiotropium alone in East Asian patients with severe/very severe COPD. METHODS: This 12-week, randomized, parallel-group, multicentre, open-label study was conducted in East Asia. After a 14-day run-in period during which patients received tiotropium 18 µg once daily, patients were randomized to tiotropium (18 µg once daily) + budesonide/formoterol (160/4.5 µg 2 inhalations twice daily) or tiotropium alone (18 µg once daily). The primary endpoint was change from baseline in pre-dose forced expiratory volume in 1 s (FEV1 ) to the mean of values measured at Weeks 1, 6 and 12. RESULTS: Pre-dose FEV1 significantly increased from baseline with tiotropium plus budesonide/formoterol (n = 287) versus tiotropium alone (n = 291) (5.0% vs 0.6%; treatment difference: 4.4% (95% CI: 1.9-6.9), P = 0.0004). Triple therapy also reduced the COPD exacerbation rate by 40.7% (P = 0.0032) and prolonged time to first exacerbation (38.6% risk reduction, P = 0.0167) versus tiotropium alone and markedly improved health-related quality of life (HRQoL), measured using the St George's Respiratory Questionnaire. Incidence of adverse events was 26% for both groups. CONCLUSIONS: In East Asian patients with severe/very severe COPD, adding budesonide/formoterol to tiotropium was associated with significant improvements in FEV1 and HRQoL and lower COPD exacerbation rates. Treatment was generally well tolerated. CLINICAL TRIAL REGISTRATION: NCT01397890 at Clinicaltrials.gov.

Meta-analysis of the adverse effects of long-term azithromycin use in patients with chronic lung diseases.

The adverse effects of azithromycin on the treatment of patients with chronic lung diseases (CLD) were evaluated in the present study. MEDLINE and other databases were searched for relevant articles published until August 2013. Randomized controlled trials that enrolled patients with chronic lung diseases who received long-term azithromycin treatment were selected, and data on microbiological studies and azithromycin-related adverse events were abstracted from articles and analyzed. Six studies were included in the meta-analysis. The risk of bacterial resistance in patients receiving long-term azithromycin treatment was increased 2.7-fold (risk ratio [RR], 2.69 [95% confidence interval {95% CI}, 1.249, 5.211]) compared with the risk in patients receiving placebo treatment. On the other hand, the risk of bacterial colonization decreased in patients receiving azithromycin treatment (RR, 0.551 [95% CI, 0.460, 0.658]). Patients receiving long-term azithromycin therapy were at risk of increased impairment of hearing (RR, 1.168 [95% CI, 1.030, 1.325]). This analysis provides evidence supporting the idea that bacterial resistance can develop with long-term azithromycin treatment. Besides the increasingly recognized anti-inflammatory role of azithromycin used in treating chronic lung diseases, we should be aware of the potential for adverse events with its long-term use.

Structure of an integrin with an alphaI domain, complement receptor type 4.

We report the structure of an integrin with an alphaI domain, alpha(X)beta(2), the complement receptor type 4. It was earlier expected that a fixed orientation between the alphaI domain and the beta-propeller domain in which it is inserted would be required for allosteric signal transmission. However, the alphaI domain is highly flexible, enabling two betaI domain conformational states to couple to three alphaI domain states, and greater accessibility for ligand recognition. Although alpha(X)beta(2) is bent similarly to integrins that lack alphaI domains, the terminal domains of the alpha- and beta-legs, calf-2 and beta-tail, are oriented differently than in alphaI-less integrins. Linkers extending to the transmembrane domains are unstructured. Previous mutations in the beta(2)-tail domain support the importance of extension, rather than a deadbolt, in integrin activation. The locations of further activating mutations and antibody epitopes show the critical role of extension, and conversion from the closed to the open headpiece conformation, in integrin activation. Differences among 10 molecules in crystal lattices provide unprecedented information on interdomain flexibility important for modelling integrin extension and activation.