TFAP2 paralogs regulate midfacial development in part through a conserved ALX genetic pathway

Cranial neural crest development is governed by positional gene regulatory networks (GRNs). Fine-tuning of the GRN components underlies facial shape variation, yet how those networks in the midface are connected and activated remain poorly understood. Here, we show that concerted inactivation of Tfap2a and Tfap2b in the murine neural crest, even during the late migratory phase, results in a midfacial cleft and skeletal abnormalities. Bulk and single-cell RNA-seq profiling reveal that loss of both TFAP2 family members dysregulates numerous midface GRN components involved in midface morphogenesis, patterning and differentiation. Notably, Alx1, Alx3 and Alx4 (ALX) transcript levels are reduced, whereas ChIP-seq analyses suggest TFAP2 family members directly and positively regulate ALX gene expression. Tfap2a, Tfap2b and ALX co-expression in midfacial neural crest cells of both mouse and zebrafish implies conservation of this regulatory axis across vertebrates. Consistent with this notion, tfap2a zebrafish mutants present with abnormal alx3 expression patterns, Tfap2a binds ALX loci and tfap2a-alx3 genetic interactions are observed. Together, these data demonstrate TFAP2 paralogs regulate vertebrate midfacial development in part by activating expression of ALX transcription factor genes.

TFAP2 paralogs regulate midfacial development in part through a conserved ALX genetic pathway

Cranial neural crest development is governed by positional gene regulatory networks (GRNs). Fine-tuning of the GRN components underly facial shape variation, yet how those in the midface are connected and activated remain poorly understood. Here, we show that concerted inactivation of Tfap2a and Tfap2b in the murine neural crest even during the late migratory phase results in a midfacial cleft and skeletal abnormalities. Bulk and single-cell RNA-seq profiling reveal that loss of both Tfap2 members dysregulated numerous midface GRN components involved in midface fusion, patterning, and differentiation. Notably, Alx1/3/4 (Alx) transcript levels are reduced, while ChIP-seq analyses suggest TFAP2 directly and positively regulates Alx gene expression. TFAP2 and ALX co-expression in midfacial neural crest cells of both mouse and zebrafish further implies conservation of this regulatory axis across vertebrates. Consistent with this notion, tfap2a mutant zebrafish present abnormal alx3 expression patterns, and the two genes display a genetic interaction in this species. Together, these data demonstrate a critical role for TFAP2 in regulating vertebrate midfacial development in part through ALX transcription factor gene expression.

FaceBase 3: analytical tools and FAIR resources for craniofacial and dental research

The FaceBase Consortium was established by the National Institute of Dental and Craniofacial Research in 2009 as a 'big data' resource for the craniofacial research community. Over the past decade, researchers have deposited hundreds of annotated and curated datasets on both normal and disordered craniofacial development in FaceBase, all freely available to the research community on the FaceBase Hub website. The Hub has developed numerous visualization and analysis tools designed to promote integration of multidisciplinary data while remaining dedicated to the FAIR principles of data management (findability, accessibility, interoperability and reusability) and providing a faceted search infrastructure for locating desired data efficiently. Summaries of the datasets generated by the FaceBase projects from 2014 to 2019 are provided here. FaceBase 3 now welcomes contributions of data on craniofacial and dental development in humans, model organisms and cell lines. Collectively, the FaceBase Consortium, along with other NIH-supported data resources, provide a continuously growing, dynamic and current resource for the scientific community while improving data reproducibility and fulfilling data sharing requirements.

The TFAP2A-IRF6-GRHL3 genetic pathway is conserved in neurulation

Mutations in IRF6, TFAP2A and GRHL3 cause orofacial clefting syndromes in humans. However, Tfap2a and Grhl3 are also required for neurulation in mice. Here, we found that homeostasis of Irf6 is also required for development of the neural tube and associated structures. Over-expression of Irf6 caused exencephaly, a rostral neural tube defect, through suppression of Tfap2a and Grhl3 expression. Conversely, loss of Irf6 function caused a curly tail and coincided with a reduction of Tfap2a and Grhl3 expression in tail tissues. To test whether Irf6 function in neurulation was conserved, we sequenced samples obtained from human cases of spina bifida and anencephaly. We found two likely disease-causing variants in two samples from patients with spina bifida. Overall, these data suggest that the Tfap2a-Irf6-Grhl3 genetic pathway is shared by two embryologically distinct morphogenetic events that previously were considered independent during mammalian development. In addition, these data suggest new candidates to delineate the genetic architecture of neural tube defects and new therapeutic targets to prevent this common birth defect.

Diagnostic delay in pulmonary arterial hypertension: Insights from the Australian and New Zealand pulmonary hypertension registry

BACKGROUND AND OBJECTIVE

Early diagnosis of PAH is clinically challenging. Patterns of diagnostic delay in Australian and New Zealand PAH populations have not been explored in large-scale studies. We aimed to evaluate the magnitude, risk factors and survival impact of diagnostic delay in Australian and New Zealand PAH patients.

METHODS

A cohort study of PAH patients from the PHSANZ Registry diagnosed from 2004 to 2017 was performed. Diagnostic interval was the time from symptom onset to diagnostic right heart catheterization as recorded in the registry. Factors associated with diagnostic delay were analysed in a multivariate logistic regression model. Survival rates were compared across patients based on the time to diagnosis using Kaplan-Meier method and Cox regression.

RESULTS

A total of 2044 patients were included in analysis. At diagnosis, median age was 58 years (IQR: 43-69), female-to-male ratio was 2.8:1 and majority of patients were in NYHA FC III-IV (82%). Median diagnostic interval was 1.2 years (IQR: 0.6-2.7). Age, CHD-PAH, obstructive sleep apnoea and peripheral vascular disease were independently associated with diagnostic interval of ≥1 year. No improvement in diagnostic interval was seen during the study period. Longer diagnostic interval was associated with decreased 5-year survival.

CONCLUSION

PAH patients experience significant diagnostic interval, which has not improved despite increased community awareness. Age, cardiovascular and respiratory comorbidities are significantly associated with longer time to diagnosis. Mortality rates appear higher in patients who experience longer diagnostic interval.

Structural features associated with multiferroic behavior in the RX3(BO3)4 system

The magnetoelectric effect in the RX₃(BO₃)₄ system (R  =  Ho, Eu, Sm, Nd, Gd; X  =  Fe, Al) varies significantly with the cation R despite very similar structural arrangements. Our structural studies reveal a symmetry reducing tilting of the BO₃ planes and of the FeO₆ polyhedra in the systems exhibiting low magnetic field induced electric polarization. Neutron scattering measurements reveal a lack of magnetic ordering indicating the primary importance of the atomic structure in the multiferroic behavior of this system.

Ep400 deficiency in Schwann cells causes persistent expression of early developmental regulators and peripheral neuropathy

Schwann cells ensure efficient nerve impulse conduction in the peripheral nervous system. Their development is accompanied by defined chromatin changes, including variant histone deposition and redistribution. To study the importance of variant histones for Schwann cell development, we altered their genomic distribution by conditionally deleting Ep400, the central subunit of the Tip60/Ep400 complex. Ep400 absence causes peripheral neuropathy in mice, characterized by terminal differentiation defects in myelinating and non-myelinating Schwann cells and immune cell activation. Variant histone H2A.Z is differently distributed throughout the genome and remains at promoters of Tfap2a, Pax3 and other transcriptional regulator genes with transient function at earlier developmental stages. Tfap2a deletion in Ep400-deficient Schwann cells causes a partial rescue arguing that continued expression of early regulators mediates the phenotypic defects. Our results show that proper genomic distribution of variant histones is essential for Schwann cell differentiation, and assign importance to Ep400-containing chromatin remodelers in the process.

The Ep400 chromatin remodeler determines genomic distribution of variant histones. In the current study, the authors show that loss of Ep400 in Schwann cells leads to aberrant expression of developmental regulators, and a peripheral neuropathy phenotype.

Developmental nonlinearity drives phenotypic robustness

Robustness to perturbation is a fundamental feature of complex organisms. Mutations are the raw material for evolution, yet robustness to their effects is required for species survival. The mechanisms that produce robustness are poorly understood. Nonlinearities are a ubiquitous feature of development that may link variation in development to phenotypic robustness. Here, we manipulate the gene dosage of a signaling molecule, Fgf8, a critical regulator of vertebrate development. We demonstrate that variation in Fgf8 expression has a nonlinear relationship to phenotypic variation, predicting levels of robustness among genotypes. Differences in robustness are not due to gene expression variance or dysregulation, but emerge from the nonlinearity of the genotype–phenotype curve. In this instance, embedded features of development explain robustness differences. How such features vary in natural populations and relate to genetic variation are key questions for unraveling the origin and evolvability of this feature of organismal development.

Developmental processes often involve nonlinearities, but the consequences for translating genotype to phenotype are not well characterized. Here, Green et al. vary Fgf8 signaling across allelic series of mice and show that phenotypic robustness in craniofacial shape is explained by a nonlinear effect of Fgf8 expression.

A tissue-specific role for intraflagellar transport genes during craniofacial development

Primary cilia are nearly ubiquitous, cellular projections that function to transduce molecular signals during development. Loss of functional primary cilia has a particularly profound effect on the developing craniofacial complex, causing several anomalies including craniosynostosis, micrognathia, midfacial dysplasia, cleft lip/palate and oral/dental defects. Development of the craniofacial complex is an intricate process that requires interactions between several different tissues including neural crest cells, neuroectoderm and surface ectoderm. To understand the tissue-specific requirements for primary cilia during craniofacial development we conditionally deleted three separate intraflagellar transport genes, Kif3a, Ift88 and Ttc21b with three distinct drivers, Wnt1-Cre, Crect and AP2-Cre which drive recombination in neural crest, surface ectoderm alone, and neural crest, surface ectoderm and neuroectoderm, respectively. We found that tissue-specific conditional loss of ciliary genes with different functions produces profoundly different facial phenotypes. Furthermore, analysis of basic cellular behaviors in these mutants suggests that loss of primary cilia in a distinct tissue has unique effects on development of adjacent tissues. Together, these data suggest specific spatiotemporal roles for intraflagellar transport genes and the primary cilium during craniofacial development.

Feasibility and Safety of a Transthoracic Pneumostoma Airway Bypass in Severe Emphysema Patients

BACKGROUND

Emphysema is characterised by airflow obstruction, hyperinflation, and resultant dyspnoea. It is worth investigating whether decompression improves lung mechanics and enhances quality of life (QoL).

OBJECTIVES

The purpose of this study was to describe the feasibility and safety of creating a transthoracic pneumostoma to enable lung reduction.

METHODS

A transthoracic 10-mm diameter Portaero Access Tube (Portaero™, Cupertino, CA, USA) was implanted via a third intercostal space incision in 15 severe emphysema patients [mean age 63 years, forced expiratory volume in 1 s 54% predicted, diffusing capacity for carbon monoxide 31% predicted, residual volume 246% predicted, Six-Minute Walk Test 296 m]. Four weeks later, an 8-mm Portaero Disposable Tube (3-8 cm in length) was substituted and changed daily thereafter. The targeted primary endpoints were a ≥12% increase in forced expiratory volume in 1 s and a decrease of ≥4 points in Saint George's Respiratory Questionnaire score at 6 months.

RESULTS

Sixteen procedures were performed on 15 patients, complicated by 1 intercostal haemorrhage, 1 pneumothorax, and universal mild surgical emphysema. Early patency issues were common, but often responded to external endoscopic debridement or argon plasma laser. Three-month patency was achieved in 9 of 15 patients, and 6 of these had long-term patency (mean of 4 years). Patency was associated with potentially useful long-term improvements or stability in spirometry, residual volume, and QoL. However, the primary endpoints were not met at 6 months.

CONCLUSION

The creation and maintenance of a transthoracic pneumostoma appears feasible and safe in patients with severe emphysema. Further studies refining patient selection (perhaps via chest computed tomography collateral ventilation and fissure assessments), techniques, and tube materials are suggested.

Sequential unilateral lung volume reduction for emphysema - Stretching the benefit

Bronchoscopic Lung Volume Reduction (BLVR) and Surgical Lung Volume Reduction (SLVR) and are two different approaches used to remodel severely emphysematous lungs to improve lung function and quality-of-life. We present a case initially referred for lung transplantation, where sequential left upper lobe BLVR and 7 years later right upper lobe SLVR, providing enduring physiological and functional improvement. The potential for sustained benefit via sequential unilateral lung volume reduction is under-appreciated.

Morphological and proteomic analysis of biofilms from the Antarctic archaeon, Halorubrum lacusprofundi

Biofilms enhance rates of gene exchange, access to specific nutrients, and cell survivability. Haloarchaea in Deep Lake, Antarctica, are characterized by high rates of intergenera gene exchange, metabolic specialization that promotes niche adaptation, and are exposed to high levels of UV-irradiation in summer. Halorubrum lacusprofundi from Deep Lake has previously been reported to form biofilms. Here we defined growth conditions that promoted the formation of biofilms and used microscopy and enzymatic digestion of extracellular material to characterize biofilm structures. Extracellular DNA was found to be critical to biofilms, with cell surface proteins and quorum sensing also implicated in biofilm formation. Quantitative proteomics was used to define pathways and cellular processes involved in forming biofilms; these included enhanced purine synthesis and specific cell surface proteins involved in DNA metabolism; post-translational modification of cell surface proteins; specific pathways of carbon metabolism involving acetyl-CoA; and specific responses to oxidative stress. The study provides a new level of understanding about the molecular mechanisms involved in biofilm formation of this important member of the Deep Lake community.

Developing a genetic manipulation system for the Antarctic archaeon, Halorubrum lacusprofundi: investigating acetamidase gene function

No systems have been reported for genetic manipulation of cold-adapted Archaea. Halorubrum lacusprofundi is an important member of Deep Lake, Antarctica (~10% of the population), and is amendable to laboratory cultivation. Here we report the development of a shuttle-vector and targeted gene-knockout system for this species. To investigate the function of acetamidase/formamidase genes, a class of genes not experimentally studied in Archaea, the acetamidase gene, amd3, was disrupted. The wild-type grew on acetamide as a sole source of carbon and nitrogen, but the mutant did not. Acetamidase/formamidase genes were found to form three distinct clades within a broad distribution of Archaea and Bacteria. Genes were present within lineages characterized by aerobic growth in low nutrient environments (e.g. haloarchaea, Starkeya) but absent from lineages containing anaerobes or facultative anaerobes (e.g. methanogens, Epsilonproteobacteria) or parasites of animals and plants (e.g. Chlamydiae). While acetamide is not a well characterized natural substrate, the build-up of plastic pollutants in the environment provides a potential source of introduced acetamide. In view of the extent and pattern of distribution of acetamidase/formamidase sequences within Archaea and Bacteria, we speculate that acetamide from plastics may promote the selection of amd/fmd genes in an increasing number of environmental microorganisms.

The FaceBase Consortium: a comprehensive resource for craniofacial researchers

The FaceBase Consortium, funded by the National Institute of Dental and Craniofacial Research, National Institutes of Health, is designed to accelerate understanding of craniofacial developmental biology by generating comprehensive data resources to empower the research community, exploring high-throughput technology, fostering new scientific collaborations among researchers and human/computer interactions, facilitating hypothesis-driven research and translating science into improved health care to benefit patients. The resources generated by the FaceBase projects include a number of dynamic imaging modalities, genome-wide association studies, software tools for analyzing human facial abnormalities, detailed phenotyping, anatomical and molecular atlases, global and specific gene expression patterns, and transcriptional profiling over the course of embryonic and postnatal development in animal models and humans. The integrated data visualization tools, faceted search infrastructure, and curation provided by the FaceBase Hub offer flexible and intuitive ways to interact with these multidisciplinary data. In parallel, the datasets also offer unique opportunities for new collaborations and training for researchers coming into the field of craniofacial studies. Here, we highlight the focus of each spoke project and the integration of datasets contributed by the spokes to facilitate craniofacial research.

Donation After Circulatory Determination of Death Lung Transplantation for Pulmonary Arterial Hypertension: Passing the Toughest Test

Lung transplantation (LTx) is a therapeutic option for severe pulmonary arterial hypertension (PAH) patients failing optimal medical therapy. The use of donation after circulatory determination of death (DCDD) donor lungs for PAH LTx has rarely been reported, primarily reflecting concerns that DCDD lungs represent extended criteria donors, at risk of morbidity and mortality. A retrospective study of all Alfred Hospital DCDD and DNDD (donation after neurologic determination of death) PAH LTx was undertaken. Protocolized fluid/inotrope/ventilator and extracorporeal membrane oxygenation (ECMO) strategies were utilized. Since our first DCDD LTx in 2006, 512 LTx have been performed. Of 31 PAH recipients, 11 received DCDD lungs (11% of DCDD LTx) and 20 received DNDD lungs (5% of DNDD LTx) (p = 0.04). Only one PAH patient died on the LTx waiting list. Peri-LTx ECMO was utilized in 3/11 (27%) DCDD and 6/20 (30%) DNDD PAH LTx (p = 0.68). Primary graft dysfunction, intensive care, and overall stay were the same in both groups. Survival at 1 and 8 years was 100% and 80% for DCDD versus 100% and 70% for DNDD LTx (p = 0.88), respectively. In conclusion, excellent results can be achieved for PAH LTx. DCDD donor lungs are not extended lungs per se having passed the toughest test.

Autoimmune disease leading to pulmonary AL amyloidosis and pulmonary hypertension

A 33-year-old woman with past history of Sjögren's syndrome and systemic lupus erythematosus presented with dyspnea and syncope secondary to pulmonary hypertension. After progressive symptoms over 4 years, she received bilateral lung transplantation. Histopathology of the explanted lungs showed isolated pulmonary amyloid light-chain amyloidosis and pulmonary cysts. No evidence of systemic amyloidosis was found at the time of transplantation. Seven years post lung transplantation, she remains well with no evidence of systemic amyloidosis recurrence.

Management of refractory chylothorax in pulmonary lymphangioleiomyomatosis

This case reports the successful management of chylothorax in a non-transplanted patient with pulmonary lymphangioleiomyomatosis (pLAM). Prolonged initial therapy failed, including total parenteral nutrition, pleural drainage, surgical pleurodesis, and pleurectomy. Commencement of sirolimus 2 mg daily (2 mg alternating days had failed) led to resolution of chylothorax after 20 days. Discontinuation of sirolimus for abdominal surgery led to recurrence of the chylothorax. Reinstitution of sirolimus led to rapid resolution of the effusion, stabilization of lung function, and there has been no recurrence in the ensuing 4 years. We conclude that sirolimus should be considered in the management of pLAM-related chylothorax, perhaps before surgical intervention.

Intermittent positive pressure ventilation increases diastolic pulmonary arterial pressure in advanced COPD

OBJECTIVES

To measure the impact of intermittent positive pressure ventilation (IPPV) on diastolic pulmonary arterial pressure (dPAP) and pulmonary pulse pressure in patients with advanced COPD.

BACKGROUND

The physiological effects of raised intrathoracic pressures upon the pulmonary circulation have not been fully established.

METHODS

22 subjects with severe COPD receiving IPPV were prospectively assessed with pulmonary and radial arterial catheterization. Changes in dPAP were assessed from end-expiration to early inspiration during low and high tidal volume ventilation.

RESULTS

Inspiration during low tidal volume IPPV increased the median [IQR] dPAP by 3.9 [2.5-4.8] mm Hg (P < 0.001). During high tidal volume, similar changes were observed. The IPPV-associated change in dPAP was correlated with baseline measures of PaO2 (rho = 0.65, P = 0.005), pH (rho = 0.64, P = 0.006) and right atrial pressure (rho = -0.53, P = 0.011).

CONCLUSIONS

In severe COPD, IPPV increases dPAP and reduces pulmonary pulse pressure during inspiration.

The Alfred Hospital Lung Transplant Experience

The management of patients undergoing lung transplantation has continued to evolve, leading to improvements in 90-day and 1-year survival. The significant advancements in donor management and utilization at our center have led to significant increases in lung transplant activity without any compromise in recipient outcomes. Through the use of a patient-centered multidisciplinary model of care involved in all aspects of recipient management, from assessment and waitlisting to pre-, peri- and post-operative care, our lung transplant outcomes represent 2015 world's best lung transplant practice.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

Pulmonary arterial remodeling in chronic obstructive pulmonary disease is lobe dependent

Abstract Pulmonary arterial remodeling has been demonstrated in patients with severe chronic obstructive pulmonary disease (COPD), but it is not known whether lobar heterogeneity of remodeling occurs. Furthermore, the relationship between pulmonary hypertension (PH) and pulmonary arterial remodeling in COPD has not been established. Muscular pulmonary arterial remodeling in arteries 0.10-0.25 mm in diameter was assessed in COPD-explanted lungs and autopsy controls. Remodeling was quantified as the percentage wall thickness to vessel diameter (%WT) using digital image analysis. Repeat measures mixed-effects remodeling for %WT was performed according to lobar origin (upper and lower), muscular pulmonary arterial size (small, medium, and large), and echocardiography-based pulmonary arterial pressure (no PH, mild PH, and moderate-to-severe PH). Lobar perfusion and emphysema indices were determined from ventilation-perfusion and computed tomography scans, respectively. Overall, %WT was greater in 42 subjects with COPD than in 5 control subjects ([Formula: see text]). Within the COPD group, %WT was greater in the upper lobes ([Formula: see text]) and in the small muscular pulmonary arteries ([Formula: see text]). Lobar differences were most pronounced in medium and large arteries. Lobar emphysema index was not associated with arterial remodeling. However, there was a significant positive relationship between the lobar perfusion index and pulmonary arterial remodeling ([Formula: see text]). The presence of PH on echocardiography showed only a trend to a small effect on lower lobe remodeling. The pattern of pulmonary arterial remodeling in COPD is complicated and lobe dependent. Differences in regional blood flow partially account for the lobar heterogeneity of pulmonary arterial remodeling in COPD.

MicroRNA-17-92, a direct Ap-2α transcriptional target, modulates T-box factor activity in orofacial clefting

Among the most common human congenital anomalies, cleft lip and palate (CL/P) affects up to 1 in 700 live births. MicroRNA (miR)s are small, non-coding RNAs that repress gene expression post-transcriptionally. The miR-17-92 cluster encodes six miRs that have been implicated in human cancers and heart development. We discovered that miR-17-92 mutant embryos had severe craniofacial phenotypes, including incompletely penetrant CL/P and mandibular hypoplasia. Embryos that were compound mutant for miR-17-92 and the related miR-106b-25 cluster had completely penetrant CL/P. Expression of Tbx1 and Tbx3, the DiGeorge/velo-cardio-facial (DGS) and Ulnar-mammary syndrome (UMS) disease genes, was expanded in miR-17-92 mutant craniofacial structures. Both Tbx1 and Tbx3 had functional miR seed sequences that mediated gene repression. Analysis of miR-17-92 regulatory regions uncovered conserved and functional AP-2α recognition elements that directed miR-17-92 expression. Together, our data indicate that miR-17-92 modulates expression of critical T-box transcriptional regulators during midface development and is itself a target of Bmp-signaling and the craniofacial pioneer factor AP-2α. Our data are the first genetic evidence that an individual miR or miR cluster is functionally important in mammalian CL/P.

Iron deficiency in patients with idiopathic pulmonary arterial hypertension

BACKGROUND

Iron deficiency has been reported to be highly prevalent in idiopathic pulmonary arterial hypertension (iPAH) patients, with the potential to influence cardiac performance, pulmonary artery pressures and the pulmonary vascular response to hypoxia.

METHODS

Iron status was evaluated in 29 iPAH patients, and was related to haemodynamic, echocardiographic and exercise parameters.

RESULTS

Iron deficiency was present in 44.8% of all iPAH patients, although anaemia was only present in 13.8%. Iron-deficient patients had similar exercise capacity (6MWD: 446±141 m), compared to iron-sufficient patients (421±193 m), however 46.2% of iron deficient patients had NYHA FC 3 or higher, compared to 12.5% in non-iron deficient group. Additionally iron-deficient patients showed increased mean pulmonary arterial pressure (63.3±12.2 mmHg; iron deficient vs. 38.8±16.7 mmHg; non-iron deficient) and reduced cardiac index (1.3±0.2 L/min/m(2); iron deficient vs. 2.5±0.4 L/min/m(2); non-iron deficient).

CONCLUSIONS

Iron deficiency is highly prevalent in iPAH, and the extent of iron deficiency is related to haemodynamics and NYHA functional class. While the exact mechanism of iron deficiency is unknown, our study suggests that treatment of iron deficiency should be considered in iPAH patients.

A technique for sexing mouse embryos by a visual colorimetric assay of the X-linked enzyme, glucose 6-phosphate dehydrogenase

Described is a simple visual, colorimetric assay for the X-linked enzyme, glucose 6-phosphate dehydrogenase (G6PD), in mouse embryos. Included is a demonstration of the effectiveness of the assay in predicting the sex of embryos prior to transfer. Scoring of embryos according to G6PD content resulted in an apparent bimodal distribution with 50% scoring as females, i.e., double dosage of G6PD, and 50% scoring as males, i.e., single dosage of G6PD. Transfer of "sexed" embryos to surrogate mothers resulted in an overall birth rate of 35% (181 516 ) compared to 46% (39 84 ) for controls. Embryos predicted as females resulted in a birth rate of 35% (86 247 ), and 72% (62 86 ) of pups born were female. Embryos predicted as males resulted in a birth rate of 35% (95 269 ), and 57% (54 95 ) of pups born were male. Overall, the accuracy of the assay was 64% (116 181 ) in predicting sex, i.e., about two-thirds of the embryos were correctly sexed prior to transfer.

Measurement of granulocyte pharmacodynamics in whole blood by flow cytometry

During the Phase I/II assessment of new therapies with the potential to suppress eosinophil and neutrophil inflammation, there is a need to assess the peripheral blood pharmacokinetic (PK) and pharmacodynamic (PD) profiles of the drug. This has relevance in respiratory disease since drugs that target eosinophillic inflammation are in development for asthma; whereas neutrophil-directed therapies are being introduced for treatment of chronic obstructive airways disease (COPD). Pharmacokinetic evaluation is required to determine the concentration of drug substance (and possibly metabolites) in peripheral blood at intervals following single or repeated dosing. Pharmacodynamic assessment is also required since many drug substances have a duration of action which is prolonged beyond the time when drug substance is detectable in the blood (see Fig. 1). Fig. 1. Whole blood pharmacodynamics. In preclinical studies, animal or human blood is treated with test agents. In clinical studies, human subjects are treated with drug and blood removed for analysis. GAFS, gated autofluorescence forward scatter; PK, pharmacokinetics; PD, pharmacoldynamics.

Impact of heart failure and changes to volume status on liver stiffness: non-invasive assessment using transient elastography

AIM

The impact of cardiac dysfunction on the liver is known as cardiac hepatopathy. In certain instances this can result in significant hepatic fibrosis or cirrhosis. The validity of non-invasive tools to assess hepatic fibrosis, such as FibroScan(®) which measures liver stiffness (LSM), has not been established in this setting. We examined the impact of cardiac dysfunction on LSM using FibroScan(®) and the influence of volume changes on LSM.

METHODS AND RESULTS

A prospective, cross-sectional study examined the use of FibroScan(®) in subjects with left-sided heart failure (LHF, n = 32), right-sided heart failure (RHF, n = 9), and acute decompensated heart failure (ADHF, n = 8). The impact of volume changes upon LSM was further examined in the ADHF group (pre- and post-diuresis) and in a haemodialysis group (HD, n = 12), pre- and post-ultrafiltration on dialysis. Compared with healthy controls [n = 55, LSM = median 4.4 (25th percentile 3.6, 75th percentile 5.1) kPa], LSM was increased in all the cardiac dysfunction subgroups [LHF, 4.7 (4.0, 8.7) kPa, P = 0.04; RHF, 9.7 (5.0, 10.8) kPa, P < 0.001; ADHF, 11.2 (6.7, 14.3) kPa, P < 0.001]. Alteration in volume status via diuresis did not change the baseline LSM in ADHF [11.2 (6.7, 14.3) to 9.5 (7.3, 21.6) kPa, P > 0.05] with mean diuresis 5051 ± 1585 mL, or ultrafiltration in HD [6.0 (3.6, 5.1) vs. 5.7 (4.8, 7.0) kPa, P > 0.05] with mean diuresis 1962 ± 233 mL.

CONCLUSION

Our findings support the concept of increased LSM in the cardiac failure population. LSM was not altered to a statistically significant level with acute volume changes.

New magnetic phase diagram of (Sr,Ca)2RuO4

High-T(c) cuprates, iron pnictides, organic BEDT and TMTSF, alkali-doped C(60), and heavy-fermion systems have superconducting states adjacent to competing states exhibiting static antiferromagnetic or spin density wave order. This feature has promoted pictures for their superconducting pairing mediated by spin fluctuations. Sr(2)RuO(4) is another unconventional superconductor which almost certainly has a p-wave pairing. The absence of known signatures of static magnetism in the Sr-rich side of the (Ca, Sr) substitution space, however, has led to a prevailing view that the superconducting state in Sr(2)RuO(4) emerges from a surrounding Fermi-liquid metallic state. Using muon spin relaxation and magnetic susceptibility measurements, we demonstrate here that (Sr,Ca)(2)RuO(4) has a ground state with static magnetic order over nearly the entire range of (Ca, Sr) substitution, with spin-glass behaviour in Sr(1.5)Ca(0.5)RuO(4) and Ca(1.5)Sr(0.5)RuO(4). The resulting new magnetic phase diagram establishes the proximity of superconductivity in Sr(2)RuO(4) to competing static magnetic order.

Spin ice: magnetic excitations without monopole signatures using muon spin rotation

Theory predicts the low temperature magnetic excitations in spin ices consist of deconfined magnetic charges, or monopoles. A recent transverse-field (TF) muon spin rotation (μSR) experiment [S. T. Bramwell et al., Nature (London) 461, 956 (2009)] reports results claiming to be consistent with the temperature and magnetic field dependence anticipated for monopole nucleation-the so-called second Wien effect. We demonstrate via a new series of μSR experiments in Dy(2)Ti(2)O(7) that such an effect is not observable in a TF μSR experiment. Rather, as found in many highly frustrated magnetic materials, we observe spin fluctuations which become temperature independent at low temperatures, behavior which dominates over any possible signature of thermally nucleated monopole excitations.

Proliferating bronchial webs after lung transplantation

This case details the decline in lung function due to bronchial webs in a lung transplant recipient. The decline occurred 2 years after transplantation and, despite therapy, the webs, which had an inflammatory component, became treatment resistant. We outline the pathological findings and management strategies used, discuss the evidence in the literature, and offer possible causes for these unusual clinical findings.

Long-term outcomes from bronchoscopic lung volume reduction using a bronchial prosthesis

BACKGROUND AND OBJECTIVE

We evaluated long-term safety and lung function outcomes in a cohort of patients with severe upper-zone heterogeneous emphysema who underwent bronchoscopic lung volume reduction (BLVR) performed with the Emphasys one-way valve.

METHODS

A retrospective cohort study was undertaken to assess long-term outcomes in 23 consecutive patients who underwent upper lobe BLVR between July 2001 and November 2003 as part of a first-in-humans study. Long-term follow up (>12 months) was available in 16/23 patients (median duration of follow up 64 months (range 15-90 months)). Both unilateral (n=4) and bilateral (n=12) BLVR procedures were performed with a mean of 6 (range 3-11) valves being inserted. Changes in pulmonary function tests were assessed longitudinally following the procedure.

RESULTS

13/16 and 11/16 patients showed post-procedure improvements in FEV1 and DL(CO) , respectively. However, early improvements in pulmonary function were not sustained with only 6/16 patients still showing improved lung function at the end of follow up. There were no significant improvements in other indices of pulmonary function. Three patients, in the absence of clinical benefit, proceeded to lung transplantation at 15, 16 and 44 months post BLVR. Four patients died during the course of the study at 27, 29, 39 and 50 months post procedure.

CONCLUSIONS

BLVR with the Emphasys one-way valve has an acceptable safety profile and in select patients may achieve long-term sustained improvements in pulmonary function.

Delta opioid receptors colocalize with corticotropin releasing factor in hippocampal interneurons

The hippocampal formation (HF) is an important site at which stress circuits and endogenous opioid systems intersect, likely playing a critical role in the interaction between stress and drug addiction. Prior study findings suggest that the stress-related neuropeptide corticotropin releasing factor (CRF) and the delta opioid receptor (DOR) may localize to similar neuronal populations within HF lamina. Here, hippocampal sections of male and cycling female adult Sprague-Dawley rats were processed for immunolabeling using antisera directed against the DOR and CRF peptide, as well as interneuron subtype markers somatostatin or parvalbumin, and analyzed by fluorescence and electron microscopy. Both DOR- and CRF-labeling was observed in interneurons in the CA1, CA3, and dentate hilus. Males and normal cycling females displayed a similar number of CRF immunoreactive neurons co-labeled with DOR and a similar average number of CRF-labeled neurons in the dentate hilus and stratum oriens of CA1 and CA3. In addition, 70% of DOR/CRF dual-labeled neurons in the hilar region co-labeled with somatostatin, suggesting a role for these interneurons in regulating perforant path input to dentate granule cells. Ultrastructural analysis of CRF-labeled axon terminals within the hilar region revealed that proestrus females have a similar number of CRF-labeled axon terminals that contain DORs compared to males but an increased number of CRF-labeled axon terminals without DORs. Taken together, these findings suggest that while DORs are anatomically positioned to modulate CRF immunoreactive interneuron activity and CRF peptide release, their ability to exert such regulatory activity may be compromised in females when estrogen levels are high.

Biotechnological uses of enzymes from psychrophiles

The bulk of the Earth's biosphere is cold (e.g. 90% of the ocean's waters are ≤ 5°C), sustaining a broad diversity of microbial life. The permanently cold environments vary from the deep ocean to alpine reaches and to polar regions. Commensurate with the extent and diversity of the ecosystems that harbour psychrophilic life, the functional capacity of the microorganisms that inhabitat the cold biosphere are equally diverse. As a result, indigenous psychrophilic microorganisms provide an enormous natural resource of enzymes that function effectively in the cold, and these cold‐adapted enzymes have been targeted for their biotechnological potential. In this review we describe the main properties of enzymes from psychrophiles and describe some of their known biotechnological applications and ways to potentially improve their value for biotechnology. The review also covers the use of metagenomics for enzyme screening, the development of psychrophilic gene expression systems and the use of enzymes for cleaning.

A comparison of the structure of solute clusters formed during thermal ageing and irradiation

Nanometre scale clusters form in Cu-containing reactor pressure vessel (RPV) steels during neutron irradiation. These clusters have a deleterious effect on mechanical properties, which can result in embrittlement and limit the reactor operating life. Thermal ageing of RPV steels can also induce the formation of solute clusters but it is not clear how similar these are to those formed during irradiation. In this work atom probe tomography, combined with detailed structural assessments of the structure of solute clusters, is used to address this issue. A series of thermal ageing heat treatments has been performed on several high- and low-Ni RPV welds to produce 1-4 nm diameter solute clusters. The same materials have also been neutron irradiated. The results show that CuMnNiSi enriched clusters formed during thermal ageing have, on average, higher Cu contents and lower Mn, Ni and Si contents than those found in irradiation-induced clusters. The effect of increasing bulk Ni is to encourage the formation of clusters with significantly higher Ni content, slightly higher Mn and Si contents and significantly lower Cu contents. At very high doses and dose rates MnNiSi enriched clusters can form even in high-Cu welds. Despite differences in the compositions of individual clusters formed during irradiation and during thermal ageing, clusters in both exhibit similar structure. In particular, well developed clusters in both materials have Cu-enriched cores whose peripheries are enriched in Ni, Mn and, in most cases, Si.

Temperature-dependent global gene expression in the Antarctic archaeon Methanococcoides burtonii

Methanococcoides burtonii is a member of the Archaea that was isolated from Ace Lake in Antarctica and is a valuable model for studying cold adaptation. Low temperature transcriptional regulation of global gene expression, and the arrangement of transcriptional units in cold-adapted archaea has not been studied. We developed a microarray for determining which genes are expressed in operons, and which are differentially expressed at low (4°C) or high (23°C) temperature. Approximately 55% of genes were found to be arranged in operons that range in length from 2 to 23 genes, and mRNA abundance tended to increase with operon length. Analysing microarray data previously obtained by others for Halobacterium salinarum revealed a similar correlation between operon length and mRNA abundance, suggesting that operons may play a similar role more broadly in the Archaea. More than 500 genes were differentially expressed at levels up to ≈ 24-fold. A notable feature was the upregulation of genes involved in maintaining RNA in a state suitable for translation in the cold. Comparison between microarray experiments and results previously obtained using proteomics indicates that transcriptional regulation (rather than translation) is primarily responsible for controlling gene expression in M. burtonii. In addition, certain genes (e.g. involved in ribosome structure and methanogenesis) appear to be regulated post-transcriptionally. This is one of few experimental studies describing the genome-wide distribution and regulation of operons in archaea.

The six-minute walk test: a useful metric for the cardiopulmonary patient

Measurement of exercise capacity is an integral element in assessment of patients with cardiopulmonary disease. The 6-min walk test (6MWT) provides information regarding functional capacity, response to therapy and prognosis across a range of chronic cardiopulmonary conditions. A distance less than 350 m is associated with increased mortality in chronic obstructive pulmonary disease, chronic heart failure and pulmonary arterial hypertension. Desaturation during a 6MWT is an important prognostic indicator for patients with interstitial lung disease. The 6MWT is sensitive to commonly used therapies in chronic obstructive pulmonary disease such as pulmonary rehabilitation, oxygen, long-term use of inhaled corticosteroids and lung volume reduction surgery. However, it appears less reliable to detect changes in clinical status associated with medical therapies for heart failure. A change in walking distance of more than 50 m is clinically significant in most disease states. When interpreting the results of a 6MWT, consideration should be given to choice of predictive values and the methods by which the test was carried out.

Bronchodilator reversibility, airway eosinophilia and anti-inflammatory effects of inhaled fluticasone in COPD are not related

BACKGROUND AND OBJECTIVE

Bronchodilator reversibility (BDR) is common in smoking-related COPD, but the airway pathology underlying this has not been described. In particular, it is not known whether BDR is associated with underlying airway eosinophilia and whether BDR is predictive of a better response to inhaled corticosteroid (ICS) treatment.

METHODS

A double-blind, placebo-controlled, randomized 2:1 study of fluticasone propionate (FP), 500 microg twice daily versus placebo over 6 months was performed in subjects with mild to moderate COPD. Subjects with a clinical history of asthma were excluded, but not on BDR criteria alone. Induced sputum, BAL and endobronchial biopsies (EBB) were performed in 36 subjects at baseline, and 30 of these provided a second full set of samples (FP, n = 19; placebo, n = 11).

RESULTS

Baseline BDR was not related to airway eosinophilia and did not predict response to ICS. Post-bronchodilator FEV(1) increased in the FP group compared with the placebo group (P = 0.05), and there were within-treatment group reductions in total symptom scores with FP (P < 0.05). Compared with placebo, FP reduced macrophage numbers but increased neutrophil numbers in EBB (P = 0.01 and P = 0.003, respectively). BAL neutrophil and epithelial cell numbers were also reduced with FP (P = 0.03 for both). There were within-treatment group reductions in the numbers of EBB mast cells and CD8+ve lymphocytes with FP (P = 0.007).

CONCLUSIONS

BDR was not related to any particular inflammatory phenotype or any clinical or anti-inflammatory response to ICS in these subjects with mild to moderate COPD.