Sleep laboratory test referrals in Canada: sleep apnea rapid response survey

BACKGROUND

An estimated 5.4 million Canadian adults have been diagnosed with sleep apnea or are at high risk of experiencing obstructive sleep apnea (OSA). There are no recent Canadian data regarding access to and predictors of referral for diagnostic testing in these populations.

METHODS

The Sleep Apnea Rapid Response survey sampled 8647 Canadian adults and captured information about risk, testing, diagnosis and treatment of sleep apnea. Predictors of sleep laboratory test referrals were assessed using log-linked binomial regression modelling. Information regarding sleep testing facilities was updated at the provincial and regional levels.

RESULTS

Approximately 76.8% (95% CI 70.1% to 83.6%) of adult Canadians with sleep apnea and 5.1% (95% CI 3.4% to 6.7%) of those at high risk for OSA reported being referred to a sleep laboratory. Significant predictors of sleep laboratory referral in the general population were male sex, middle age, overweight or obese, a chronic condition, having a regular medical doctor and reporting symptoms of sleep apnea. Region of residence was also a predictor of reported sleep laboratory referral, with individuals from Ontario being more likely to report being referred to a sleep laboratory versus individuals from other regions.

CONCLUSION

Individuals reporting risk factors and symptoms associated with OSA were more likely to report a sleep laboratory testing referral compared with those without risk factors or symptoms. However, Canada's diagnostic sleep laboratory testing capacity varies across regions and is believed to be inadequate given the number of individuals at high risk for OSA who did not report testing referral.

Antagonistic regulation by the transcription factors C/EBPα and MITF specifies basophil and mast cell fates

It remains unclear whether basophils and mast cells are derived from a common progenitor. Furthermore, how basophil versus mast cell fate is specified has not been investigated. Here, we have identified a population of granulocyte-macrophage progenitors (GMPs) that were highly enriched in the capacity to differentiate into basophils and mast cells while retaining a limited capacity to differentiate into myeloid cells. We have designated these progenitor cells "pre-basophil and mast cell progenitors" (pre-BMPs). STAT5 signaling was required for the differentiation of pre-BMPs into both basophils and mast cells and was critical for inducing two downstream molecules: C/EBPα and MITF. We have identified C/EBPα as the critical basophil transcription factor for specifying basophil cell fate and MITF as the crucial transcription factor for specifying mast cell fate. C/EBPα and MITF silenced each other's transcription in a directly antagonistic fashion. Our study reveals how basophil and mast cell fate is specified.

Dysfunctional resident lung mesenchymal stem cells contribute to pulmonary microvascular remodeling

Pulmonary vascular remodeling and oxidative stress are common to many adult lung diseases. However, little is known about the relevance of lung mesenchymal stem cells (MSCs) in these processes. We tested the hypothesis that dysfunctional lung MSCs directly participate in remodeling of the microcirculation. We employed a genetic model to deplete extracellular superoxide dismutase (EC-SOD) in lung MSCs coupled with lineage tracing analysis. We crossed ^floxpsod3 and mT/mG reporter mice to a strain expressing Cre recombinase under the control of the ABCG2 promoter. We demonstrated In vivo that depletion of EC-SOD in lung MSCs resulted in their contribution to microvascular remodeling in the smooth muscle actin positive layer. We further characterized lung MSCs to be multipotent vascular precursors, capable of myofibroblast, endothelial and pericyte differentiation in vitro. EC-SOD deficiency in cultured lung MSCs accelerated proliferation and apoptosis, restricted colony-forming ability, multilineage differentiation potential and promoted the transition to a contractile phenotype. Further studies correlated cell dysfunction to alterations in canonical Wnt/β-catenin signaling, which were more evident under conditions of oxidative stress. Our data establish that lung MSCs are a multipotent vascular precursor population, a population which has the capacity to participate in vascular remodeling and their function is likely regulated in part by the Wnt/β-catenin signaling pathway. These studies highlight an important role for microenviromental regulation of multipotent MSC function as well as their potential to contribute to tissue remodeling.

Age of transfused blood is not associated with increased postoperative adverse outcome after cardiac surgery

BACKGROUND

This study investigated the hypothesis that storage age of transfused red blood cells (RBCs) is associated with adverse outcome after cardiac surgery, and examined association between volume of RBC transfusions and outcome after cardiac surgery.

METHODS

Adult patients undergoing first time elective/urgent cardiac surgery who had received RBC transfusion perioperatively were included. Three prospective institutional databases were linked. Patients were grouped according to the oldest storage age of any RBCs transfused: those who received only RBCs stored for ≤14 days, only RBCs stored for >14 days, and a mixture of both ages of blood. The effect of RBC age on early mortality, postoperative ventilation ≥72 h, renal failure, pulmonary and infectious complications, length of intensive care stay, and postoperative ventilation time was examined using regression analyses with adjustment for confounding factors, including number of units transfused.

RESULTS

Data were analysed on 1153 patients who received a total of 5962 RBC units. There was no difference in adjusted odds of any outcome between the ≤14 days group and the group who received RBCs aged >14 days. Multivariate logistic regression analyses disclosed number of RBC units transfused as the most consistent factor associated with major postoperative complications, P<0.0001 in all cases. A trend of increasing complication rate was observed with more units transfused.

CONCLUSIONS

Storage age of RBC transfusion up to 35 days was not associated with increased postoperative adverse outcome after cardiac surgery. The number of RBC units transfused is consistently associated with adverse outcome.

Abstract 5778: Fragment-based drug discovery of selective inhibitors of fibroblast growth factor receptor (FGFr)

Recent data in a number of tumour types has implicated Fibroblast Growth Factor (FGF) and Fibroblast Growth Factor receptor (FGFr) signalling as being key to the molecular pathology of cancer. This poster will describe fragment based drug discovery using biophysical screening to identify initial fragments. Subsequently, in the fragments-to-leads stage a detailed structural understanding of the binding interactions between the fragment and its target protein utilised X-ray crystallography and NMR. Starting with different fragments allows several lead series to be identified, often by synthesizing only small numbers of compounds.

A fragment screening campaign was conducted against the FGFr-1 to detect very low molecular weight compounds that bound to the hinge region of the kinase. The screening produced several fragment molecules (Molecular Weight &lt;250 Da) which were in the micromolar range and confirmed binding mode in X-ray crystallography. One X-ray hit series that was 120 uM verse FGFr-3 will be described. Several iterations of structure-guided medicinal chemistry led to the identification of a lead compound with 3 nM affinity for FGFr-3, good cell activity and 30-fold selectivity verse VEGFr-2 with good oral activity. The lead was optimised to afford a compound that showed good PK/PD and efficacy.

This poster represents first disclosure of the structure of the lead series and illustrates how a fragment-based drug discovery approach can be efficiently used to discover compounds advanced nanomolar compounds with oral bioavailability.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5778.

Economic evaluation of diagnosing and excluding ectopic pregnancy

BACKGROUND

The diagnosis of ectopic pregnancy in women presenting in early pregnancy is often protracted, relying on costly investigations that are psychologically burdensome to the patient. The aim of this study was to evaluate the financial costs to the health services in Scotland of the current methods used to diagnose and exclude ectopic pregnancy, and compare these with that of a theoretical single diagnostic serum biomarker.

METHODS

We conducted a retrospective cost-description analysis (with and without costs of diagnostic laparoscopy) of the health-care costs incurred by all patients presenting to a large Scottish teaching hospital between June and September 2006 with pain and bleeding in early pregnancy, where ectopic pregnancy was not excluded. Additionally, a cost minimization analysis was performed for the costs of current ectopic pregnancy investigations versus those of a theoretical single diagnostic serum biomarker. This included sensitivity analyses where the biomarker was priced at increasing values and assumed to have less than 100% diagnostic sensitivity and specificity.

RESULTS

About 175 patients were eligible to be included in the analysis. Forty-seven per cent of patients required more than three visits to diagnose or exclude ectopic pregnancy. The total yearly cost for diagnosing and excluding ectopic pregnancy was 197K pound sterling for the hospital stated, and was estimated to be 1364K pound sterling for Scotland overall. Using a theoretical diagnostic serum biomarker we calculated that we could save health services up to 976K pound sterling (lowest saving 251K pound sterling after subanalysis) every year in Scotland.

CONCLUSIONS

Ectopic pregnancy is expensive to diagnose and exclude, and the investigation process is often long and might involve significant psychological morbidity. The development of a single diagnostic serum biomarker would minimize this morbidity and lead to significant savings of up to 1 million pounds per year in Scotland.