High-flux Hemodialysis Does Not Increase Vitamin B Loss Compared With Low-flux Hemodialysis.

OBJECTIVES: A consistent effect of hemodialysis (HD) on vitamin B loss has not been fully demonstrated and the effect of high-flux hemodialysis (HFHD) is also inconclusive. The aim of this study was to identify the loss of vitamin B1, B3, B5, and B6 in a single HD session and to evaluate the effect of HFHD on vitamin B removal. METHODS: Patients on maintenance HD were enrolled in this study. They were divided into low-flux hemodialysis (LFHD) group and HFHD group. Vitamin B1, B3, B5, and B6 (pyridoxal 5'-phosphate [PLP]) concentrations in blood pre- and post-HD sessions, as well as in the spent dialysate were measured. Loss of vitamin B was calculated and the difference in vitamin B loss between the 2 groups was compared. The association between HFHD and vitamin B loss was estimated using multivariable linear regression analysis. RESULTS: Seventy-six patients were included, of whom 29 were on LFHD and 47 were on HFHD. The median reduction ratio of serum vitamins B1, B3, B5, and B6 after a single HD session was 38.1%, 24.9%, 48.4%, and 44.7%, respectively. The median concentration of vitamins B1, B3, B5, and B6 in the dialysate was 0.3 µg/L, 2.9 µg/mL, 2.0 µg/L, and 0.4 ng/mL. There was no difference in either the reduction ratio of vitamin B in blood, or the concentration in dialysate between LFHD and HFHD groups. After adjusting for covariates by multivariable regression, HFHD had no effect on vitamin B1, B3, B5, or B6 removal. CONCLUSIONS: Vitamins B1, B3, B5, and B6 can be removed by HD and HFHD does not increase the loss.

There is no association of serum vitamin B levels with all-cause and cardiovascular mortality in hemodialysis patients.

INTRODUCTION: The impact of vitamin B metabolic disorders on hemodialysis (HD) patients' survival is unknown. This study is to investigate the association of serum vitamin B1, B3, B5, and B6 with all-cause and cardiovascular (CV) mortality in HD patients. METHODS: Patients' baseline serum vitamin B1, B3, B5, and B6 levels were collected, and they were followed up for the occurrence of all-cause and CV death. Kaplan-Meier analysis and Cox proportional hazards model were used to examine the association of vitamin B with mortality. RESULTS: Seventy-six HD patients were included. The median follow-up time was 99 months. Kaplan-Meier analysis showed that baseline vitamin B5 < 69.0 nmol/L and vitamin B6 < 8.1 ng/ml were associated with a higher risk of CV mortality, but these associations were nullified after adjustment. CONCLUSIONS: Serum vitamins B1, B3, B5, and B6 were not associated with all-cause or CV mortality in HD patients. CLINICAL TRIAL REGISTRY: ChiCTR2200057078 (Chinese Clinical Trial Registry, https://www.chictr.org.cn/).

Risk assessment of failure during transitioning from in-centre to home haemodialysis.

BACKGROUND: Introducing a de-novo home haemodialysis (HHD) program often raises safety concerns as errors could potentially lead to serious adverse events. Despite the complexity of performing haemodialysis at home without the supervision of healthcare staff, HHD has a good safety record. We aim to pre-emptively identify and reduce the risks to our new HHD program by risk assessment and using failure mode and effects analysis (FMEA) to identify potential defects in the design and planning of HHD. METHODS: We performed a general risk assessment of failure during transitioning from in-centre to HHD with a failure mode and effects analysis focused on the highest areas of failure. We collaborated with key team members from a well-established HHD program and one HHD patient. Risk assessment was conducted separately and then through video conference meetings for joint deliberation. We listed all key processes, sub-processes, step and then identified failure mode by scoring based on risk priority numbers. Solutions were then designed to eliminate and mitigate risk. RESULTS: Transitioning to HHD was found to have the highest risk of failure with 3 main processes and 34 steps. We identified a total of 59 areas with potential failures. The median and mean risk priority number (RPN) scores from failure mode effect analysis were 5 and 38, with the highest RPN related to vascular access at 256. As many failure modes with high RPN scores were related to vascular access, we focussed on FMEA by identifying the risk mitigation strategies and possible solutions in all 9 areas in access-related medical emergencies in a bundled- approach. We discussed, the risk reduction areas of setting up HHD and how to address incidents that occurred and those not preventable. CONCLUSIONS: We developed a safety framework for a de-novo HHD program by performing FMEA in high-risk areas. The involvement of two teams with different clinical experience for HHD allowed us to successfully pre-emptively identify risks and develop solutions.

Telemedicine and Haemodialysis Care during the COVID-19 Pandemic: An Integrative Review of Patient Safety, Healthcare Quality, Ethics and the Legal Considerations in Singapore Practice.

The COVID-19 pandemic has been an unprecedented health crisis for the general population as well as for patients with chronic illnesses such as those requiring maintenance dialysis. Patients suffering from chronic kidney disease requiring dialysis are considered a high-risk population. Multiple reports have highlighted an increased need for intensive care and higher death rates among this group of patients. Most maintenance dialysis patients are in-centre haemodialysis patients who receive treatment in shared facilities (community dialysis centres). The inability to maintain social distancing in these facilities has led to case clustering among patients and staff. This poses a substantial risk to the patients, their household members, and the wider community. To mitigate the risks of COVID-19 transmission, telemedicine was rapidly adopted in the past year by nephrologists and other allied-health staff to provide care via remote consultations and reviews. Telemedicine poses unique challenges even in an era where so much is performed online with a high degree of success and satisfaction. In applying distant clinical care for maintenance haemodialysis patients via telemedicine, there is a need to ensure adequate protection for the health and safety of patients as well as understand the ethical and legal implications of telemedicine. We discussed, in this article, these three core aspects of patient safety and quality, ethics and legal implications in telemedicine, and how each of these is crucial to the safe and effective delivery of care in general as well as unique aspects of this in Singapore.

Heterogeneity of non-cystic-fibrosis bronchiectasis in multiethnic Singapore: A prospective cohort study at a tertiary pulmonology centre.

INTRODUCTION: Non-cystic fibrosis bronchiectasis (NCFB) is a highly heterogenous disease. We describe the clinical characteristics of NCFB patients and evaluate the performance of Bronchiectasis Severity Index (BSI) in predicting mortality. METHODS: Patients attending the bronchiectasis clinic between August 2015 and April 2020 with radiologically proven bronchiectasis on computed tomography were recruited. Clinical characteristics, spirometry, radiology, microbiology and clinical course over a median period of 2.4 years is presented. RESULTS: A total of 168 patients were enrolled in this prospective cohort study. They were predominantly women (67.8%), Chinese (87.5%) and never-smokers (76.9%). Median age of diagnosis was 64 years (interquartile range 56-71) and the most common aetiology was "idiopathic" bronchiectasis (44.6%). Thirty-nine percent had normal spirometries. Compared to female patients, there were more smokers among the male patients (53.8% versus 8.5%, P<0.001) and a significantly larger proportion with post-tuberculous bronchiectasis (37.0% vs 15.8%, P=0.002). Fifty-five percent of our cohort had a history of haemoptysis. Lower body mass index, presence of chronic obstructive pulmonary disease, ever-smoker status, modified Reiff score, radiological severity and history of exacerbations were risk factors for mortality. Survival was significantly shorter in patients with severe bronchiectasis (BSI>9) compared to those with mild or moderate disease (BSI<9). The hazard ratio for severe disease (BSI>9) compared to mild disease (BSI 0-4) was 14.8 (confidence interval 1.929-114.235, P=0.01). CONCLUSION: The NCFB cohort in Singapore has unique characteristics with sex differences. Over half the patients had a history of haemoptysis. The BSI score is a useful predictor of mortality in our population.

Phase Behavior of Polyglycerol Ester-Based Nanoemulsions.

Nanoemulsions were prepared using polyglycerol esters as emulsifiers. The effects of emulsifiers, oils, and polyols on the phase behavior of nanoemulsions were analyzed by phase diagram method using caprylic acid capric triglyceride (318), mineral oil, and squalane (Squ) as oils respectively. Various factors affecting the area of the oil-in-water (O/W) nanoemulsion were investigated. The results showed that hydrophilic polyglyceryl-4 laurate was beneficial to the formation of translucent nanoemulsions, while lipophilic polyglyceryl-4 oleate could synergize the emulsification performance and was more conducive to the formation of nanoemulsions; the type of oil could affect the emulsifying ability of the emulsifier. It was found that it was beneficial to form translucent nanoemulsion when caprylic acid capric triglyceride was adopted as oil. However, it was almost impossible to form translucent nanoemulsions when mineral oil and squalane were used as oils. The addition of water-soluble jojoba ester was beneficial to the formation of O/W emulsion. In addition, glycerin can improve the polarity of the aqueous medium, enhance the affinity between emulsifiers and aqueous medium, and help to form a translucent nanoemulsion.

Telemedicine in the Satellite Dialysis Unit: Is It Feasible and Safe?

Telemedicine has gained popularity during the recent COVID-19 pandemic. Regular and timely physician review is an essential component of care for the maintenance of hemodialysis patients. While it is widely acknowledged that telemedicine cannot fully replace the role of physical review in this group of patients with organ failure, it can perhaps reduce the reliance on physical review or serve as a filter and triage in determining which patient requires actual physical review. The use of technology in any healthcare setting should always align with existing clinical workflow and protocols. We discuss the safety and quality aspects of this new concept applied to the satellite dialysis unit.

Impact of structured curriculum with simulation on bronchoscopy.

BACKGROUND AND OBJECTIVE: Simulation enhances a physician's competency in procedural skills by accelerating ascent of the learning curve. Training programmes are moving away from the Halstedian model of 'see one, do one, teach one', also referred as medical apprenticeship. We aimed to determine if a 3-month structured bronchoscopy curriculum that incorporated simulator training could improve bronchoscopy competency among pulmonary medicine trainees. METHODS: We prospectively recruited trainees from hospitals with accredited pulmonary medicine programmes. Trainees from hospitals (A, B and C) were assigned to control group (CG) where they received training by traditional apprenticeship while trainees from hospital D were assigned to intervention group (IG) where they underwent 3-month structured curriculum that incorporated training with the bronchoscopy simulator. Two patient bronchoscopy procedures per trainee were recorded on video and scored independently by two expert bronchoscopists using the modified Bronchoscopy Skills and Tasks Assessment Tool (BSTAT) forms. A 25 multiple choice questions (MCQ) test was administered to all participants at the end of 3 months. RESULTS: Eighteen trainees participated; 10 in CG and eight in IG with equal female:male ratio. Competency assessed by modified BSTAT and MCQ tests was variable and not driven by volume as IG performed fewer patient bronchoscopies but demonstrated better BSTAT, airway anaesthesia and MCQ scores. Bronchoscopy simulator training was the only factor that correlated with better BSTAT (r = 0.80), MCQ (r = 0.85) and airway anaesthesia scores (r = 0.83), and accelerated the learning curve of IG trainees. CONCLUSION: An intensive 3-month structured bronchoscopy curriculum that incorporated simulator training led to improved cognitive and technical skill performance as compared with apprenticeship training.

The Influence of Altitude on Erythropoietin Resistance Index in Maintenance Hemodialysis Patients: Data from Tibetan Plateau.

BACKGROUND: It is known that hypoxia influences many of the biologic processes involved in erythropoiesis; therefore, the high-altitude hypoxia may affect erythropoietin (EPO) responsiveness in maintenance hemodialysis (MHD) patients. This study aimed to evaluate the impact of altitude on EPO responsiveness in MHD patients. METHODS: In this retrospective study, MHD patients from Tibet Autonomous Region People's Hospital (3,650 m above sea level) and Peking University People's Hospital (43.5 m above sea level) were recruited between May 2016 and December 2018. Patients were divided into 2 groups according to altitude. Variables including age, sex, dialysis vintage, dialysis modality, duration of EPO use, EPO doses, and laboratory tests were collected and analyzed. EPO responsiveness was measured in terms of the EPO resistance index (ERI). ERI was defined as the weekly weight-adjusted dose of EPO (IU/kg/week) divided by hemoglobin concentration (g/dL). The association between ERI and altitude was estimated using a multivariable linear regression model. RESULTS: Sixty-two patients from Tibet Autonomous Region People's Hospital (high-altitude [HA] group) and 102 patients from Peking University People's Hospital (low-altitude [LA] group) were recruited. The ERI for HA group and LA group was 6.9 ± 5.1 IU w-1 kg-1 (g/dL)-1 and 11.5 ± 6.4 IU w-1 kg-1 (g/dL)-1, respectively. After adjusting for covariates by multivariable regression, altitude was independently associated with ERI (R2 = 0.245, p < 0.001). CONCLUSION: Altitude had an independent negative correlation with ERI. This result supported the hypothesis that altitude-associated hypoxia improved EPO responsiveness in MHD patients.

Heterogeneity of non-cystic-fibrosis bronchiectasis in multiethnic Singapore: A prospective cohort study at a tertiary pulmonology centre

INTRODUCTION@#Non-cystic fibrosis bronchiectasis (NCFB) is a highly heterogenous disease. We describe the clinical characteristics of NCFB patients and evaluate the performance of Bronchiectasis Severity Index (BSI) in predicting mortality.@*METHODS@#Patients attending the bronchiectasis clinic between August 2015 and April 2020 with radiologically proven bronchiectasis on computed tomography were recruited. Clinical characteristics, spirometry, radiology, microbiology and clinical course over a median period of 2.4 years is presented.@*RESULTS@#A total of 168 patients were enrolled in this prospective cohort study. They were predominantly women (67.8%), Chinese (87.5%) and never-smokers (76.9%). Median age of diagnosis was 64 years (interquartile range 56-71) and the most common aetiology was "idiopathic" bronchiectasis (44.6%). Thirty-nine percent had normal spirometries. Compared to female patients, there were more smokers among the male patients (53.8% versus 8.5%, @*CONCLUSION@#The NCFB cohort in Singapore has unique characteristics with sex differences. Over half the patients had a history of haemoptysis. The BSI score is a useful predictor of mortality in our population.

Polyether-modified siloxane stabilized dispersion system on the physical stability and control release of double (W/O/W) emulsions.

In this work, three different polyether-modified siloxanes (PMS1, PMS2, and PMS3) were applied to stabilize water-in-oil emulsions, and sodium caseinate (SC) was used to establish water-in-oil-in-water (W/O/W) emulsions. Here, PMS polymers were modified by Isolan GPS and SC by Tween 80. The impact of modifications on the physical stability and controlled release of W/O/W emulsions were investigated. It was found that the storage stability and control release of double emulsions were dependent on the types of PMS used, percent of Isolan GPS, and Tween 80. When PMS1 and PMS2 were combined with low percent of Isolan GPS and Tween 80, the dispersed droplet sizes were reduced, lower percent in the gravitational sedimentation were achieved than using PMS3 emulsions. The controlled releases of Mg2+ from W/O/W emulsions by using PMS3 were slower than using other PMS. PMS3 had a strong influence in controlling the release of Mg2+ from the double emulsions.

Utility of routine screening for alpha-1 antitrypsin deficiency in patients with bronchiectasis.

Alpha-1 antitrypsin deficiency (AATD) is a cause of bronchiectasis. Guidelines for bronchiectasis from the British Thoracic Society do not recommend to routinely test patients for AATD. In contrast, guidelines for AATD recommend routine screening. This contradiction, in part, results from the lack of data from large studies performing comprehensive screening. We screened 1600 patients with bronchiectasis at two centres in the UK from 2012 to 2016. In total, only eight individuals with AATD were identified representing 0.5% of the overall population. We conclude that routine screening for AATD in bronchiectasis in the UK has a low rate of detection. Further studies are required in different geographical regions, which may have a higher prevalence of AATD.

Distinct "Immunoallertypes" of Disease and High Frequencies of Sensitization in Non-Cystic Fibrosis Bronchiectasis.

RATIONALE: Allergic sensitization is associated with poor clinical outcomes in asthma, chronic obstructive pulmonary disease, and cystic fibrosis; however, its presence, frequency, and clinical significance in non-cystic fibrosis bronchiectasis remain unclear. OBJECTIVES: To determine the frequency and geographic variability that exists in a sensitization pattern to common and specific allergens, including house dust mite and fungi, and to correlate such patterns to airway immune-inflammatory status and clinical outcomes in bronchiectasis. METHODS: Patients with bronchiectasis were recruited in Asia (Singapore and Malaysia) and the United Kingdom (Scotland) (n = 238), forming the Cohort of Asian and Matched European Bronchiectasis, which matched recruited patients on age, sex, and bronchiectasis severity. Specific IgE response against a range of common allergens was determined, combined with airway immune-inflammatory status and correlated to clinical outcomes. Clinically relevant patient clusters, based on sensitization pattern and airway immune profiles ("immunoallertypes"), were determined. MEASUREMENTS AND MAIN RESULTS: A high frequency of sensitization to multiple allergens was detected in bronchiectasis, exceeding that in a comparator cohort with allergic rhinitis (n = 149). Sensitization was associated with poor clinical outcomes, including decreased pulmonary function and more severe disease. "Sensitized bronchiectasis" was classified into two immunoallertypes: one fungal driven and proinflammatory, the other house dust mite driven and chemokine dominant, with the former demonstrating poorer clinical outcome. CONCLUSIONS: Allergic sensitization occurs at high frequency in patients with bronchiectasis recruited from different global centers. Improving endophenotyping of sensitized bronchiectasis, a clinically significant state, and a "treatable trait" permits therapeutic intervention in appropriate patients, and may allow improved stratification in future bronchiectasis research and clinical trials.

Choosing the right mask for your Asian patient with sleep apnoea: A randomized, crossover trial of CPAP interfaces.

BACKGROUND AND OBJECTIVE: A major challenge with the treatment of obstructive sleep apnoea (OSA) is adherence to continuous positive airway pressure (CPAP) therapy. Mask tolerability is an important determinant of adherence, however evidence to guide selection of mask interfaces is lacking. METHODS: We conducted a randomized crossover trial of mask interfaces in CPAP therapy for moderate-to-severe OSA to assess adherence and efficacy of CPAP therapy with nasal mask, nasal pillow and oronasal masks. Demographic data, Nasal Obstruction Symptom Evaluation (NOSE) scores and craniofacial measurements were also analysed for associations with adherence with oronasal masks. RESULTS: Eighty-five patients were included in the study (mean ± SD age: 46 ± 12 years; body mass index: 29.9 ± 5.6 kg/m2 ; apnoea-hypopnoea index (AHI): 53.6 ± 24.0 events/h). Patients had better adherence with nasal masks (average night use: 3.96 ± 2.26 h/night) compared to oronasal masks (3.26 ± 2.18 h/night, P < 0.001) and nasal pillows (3.48 ± 2.20 h/night, P = 0.007). Residual AHI was higher with oronasal masks (7.2 ± 5.2) compared to nasal masks (4.0 ± 4.2, P < 0.001) and nasal pillows (4.1 ± 3.3, P < 0.001). Twenty-two (25.9%) patients had the best adherence with oronasal masks (4.22 ± 2.14 vs 2.93 ± 2.12 h/night, P = 0.016). These patients had lower NOSE scores (15 (0-35) vs 40 (10-55), P = 0.024) and larger menton-labrale inferioris/biocular width ratios (31 ± 3% vs 28 ± 4%, P = 0.019). CONCLUSION: Nasal masks are the preferred interface during CPAP initiation. Patients with less nasal obstruction and a proportionally increased chin-lower lip distance to mid-face width may have better CPAP adherence with an oronasal mask interface.

Immunological corollary of the pulmonary mycobiome in bronchiectasis: the CAMEB study.

Understanding the composition and clinical importance of the fungal mycobiome was recently identified as a key topic in a "research priorities" consensus statement for bronchiectasis.Patients were recruited as part of the CAMEB study: an international multicentre cross-sectional Cohort of Asian and Matched European Bronchiectasis patients. The mycobiome was determined in 238 patients by targeted amplicon shotgun sequencing of the 18S-28S rRNA internally transcribed spacer regions ITS1 and ITS2. Specific quantitative PCR for detection of and conidial quantification for a range of airway Aspergillus species was performed. Sputum galactomannan, Aspergillus specific IgE, IgG and TARC (thymus and activation regulated chemokine) levels were measured systemically and associated to clinical outcomes.The bronchiectasis mycobiome is distinct and characterised by specific fungal genera, including Aspergillus, Cryptococcus and ClavisporaAspergillus fumigatus (in Singapore/Kuala Lumpur) and Aspergillus terreus (in Dundee) dominated profiles, the latter associating with exacerbations. High frequencies of Aspergillus-associated disease including sensitisation and allergic bronchopulmonary aspergillosis were detected. Each revealed distinct mycobiome profiles, and associated with more severe disease, poorer pulmonary function and increased exacerbations.The pulmonary mycobiome is of clinical relevance in bronchiectasis. Screening for Aspergillus-associated disease should be considered even in apparently stable patients.

A new therapeutic avenue for bronchiectasis: Dry powder inhaler of ciprofloxacin nanoplex exhibits superior ex vivo mucus permeability and antibacterial efficacy to its native ciprofloxacin counterpart.

Non-cystic fibrosis bronchiectasis (NCFB) characterized by permanent bronchial dilatation and recurrent infections has been clinically managed by long-term intermittent inhaled antibiotic therapy among other treatments. Herein we investigated dry powder inhaler (DPI) formulation of ciprofloxacin (CIP) nanoplex with mannitol/lactose as the excipient for NCFB therapy. The DPI of CIP nanoplex was evaluated against DPI of native CIP in terms of their (1) dissolution characteristics in artificial sputum medium, (2) ex vivo mucus permeability in sputum from NCFB and healthy individuals, (3) antibacterial efficacy in the presence of sputum against clinical Pseudomonas aeruginosa strains (planktonic and biofilm), and (4) cytotoxicity towards human lung epithelial cells. Despite their similarly fast dissolution rates in sputum, the DPI of CIP nanoplex exhibited superior mucus permeability to the native CIP (5-7 times higher) attributed to its built-in ability to generate highly supersaturated CIP concentration in the sputum. The superior mucus permeability led to the CIP nanoplex's higher antibacterial efficacy (>3 log10 CFU/mL). The DPI of CIP nanoplex exhibited similar cytotoxicity towards the lung epithelial cells as the native CIP indicating its low risk of toxicity. These results established the promising potential of DPI of CIP nanoplex as a new therapeutic avenue for NCFB.

Fampridine is a Substrate and Inhibitor of Human OCT2, but not of Human MATE1, or MATE2K.

PURPOSE: The renal clearance of fampridine (Fampyra®, or Ampyra®) significantly exceeds the glomerular filtration rate, suggesting active renal secretion is likely the major elimination pathway. The goal of this study was to identify the renal transporters that are involved in the renal active secretion, and elucidate the active renal secretion mechanism of fampridine. METHODS: The uptake of fampridine to HEK-293 cells overexpressing human OCT2, MATE1 or MATE2K was determined in the absence and presence of Cimetidine, the prototypical inhibitor of the transporters. The inhibition potential of fampridine on the renal transporters was evaluated by determining the uptake of TEA and Metformin, the probe substrates of the transporters of OCT2 and MATEs, respectively, in the absence or presence of fampridine. RESULTS: Significant time- and concentration-dependent uptake of fampridine by human OCT2 was observed. The Km and Vmax were determined as 51.0 ± 17.1 µM and 1107 ± 136 pmole/min/106 cells, respectively. Fampridine also inhibited OCT2 mediated uptake of Metformin with estimated IC50 of 66.8 µM. In contrast, there was not significant uptake of fampridine by human MATE1 or MATE2K, and fampridine did not inhibit MATE1 or MATE2K mediated uptake of TEA. CONCLUSION: The studies indicated fampridine is a substrate and inhibitor of OCT2, but not MATE1 or MATE2K. Results from the study suggested the active renal secretion of fampridine is mediated by human OCT2 but not MATE1 or MATE2K. To our knowledge, fampridine is the first reported substrate specific to OCT2 but not to MATE1 or MATE2K.

Unsupervised Medical Entity Recognition and Linking in Chinese Online Medical Text.

Online medical text is full of references to medical entities (MEs), which are valuable in many applications, including medical knowledge-based (KB) construction, decision support systems, and the treatment of diseases. However, the diverse and ambiguous nature of the surface forms gives rise to a great difficulty for ME identification. Many existing solutions have focused on supervised approaches, which are often task-dependent. In other words, applying them to different kinds of corpora or identifying new entity categories requires major effort in data annotation and feature definition. In this paper, we propose unMERL, an unsupervised framework for recognizing and linking medical entities mentioned in Chinese online medical text. For ME recognition, unMERL first exploits a knowledge-driven approach to extract candidate entities from free text. Then, the categories of the candidate entities are determined using a distributed semantic-based approach. For ME linking, we propose a collaborative inference approach which takes full advantage of heterogenous entity knowledge and unstructured information in KB. Experimental results on real corpora demonstrate significant benefits compared to recent approaches with respect to both ME recognition and linking.

Monoclonal antibody exposure in rat and cynomolgus monkey cerebrospinal fluid following systemic administration.

BACKGROUND: Many studies have focused on the challenges of small molecule uptake across the blood-brain barrier, whereas few in-depth studies have assessed the challenges with the uptake of antibodies into the central nervous system (CNS). In drug development, cerebrospinal fluid (CSF) sampling is routinely used as a surrogate for assessing CNS drug exposure and biomarker levels. In this report, we have studied the kinetic correlation between CSF and serum drug concentration-time profiles for five humanized monoclonal antibodies in rats and cynomolgus monkeys and analyzed factors that affect their CSF exposure. RESULTS: Upon intravenous (IV) bolus injection, antibodies entered the CNS slowly and reached maximum CSF concentration ( CSF T max ) in one to several days in both rats and monkeys. Antibody serum and CSF concentration-time curves converged until they became parallel after CSF T max was reached. Antibody half-lives in CSF ( CSF t ½ ) approximated their serum half-lives ( serum t ½ ). Although the intended targets of these antibodies were different, the steady-state CSF to serum concentration ratios were similar at 0.1-0.2% in both species. Independent of antibody target and serum concentration, CSF-to-serum concentration ratios for individual monkeys ranged by up to tenfold from 0.03 to 0.3%. CONCLUSION: Upon systemic administration, average antibodies CSF-to-serum concentration ratios in rats and monkeys were 0.1-0.2%. The CSF t ½ of the antibodies was largely determined by their long systemic t ½ ( systemic t ½ ).

Role of bronchoprovocation tests in identifying exercise-induced bronchoconstriction in a non-athletic population: a pilot study.

BACKGROUND: Studies on diagnostic tests for exercise-induced bronchoconstriction (EIB) have centered around the asthmatic and elite athletic population. Traditionally, the exercise challenge test (ET) was recommended to assess EIB. We aimed to compare the performance of surrogate testing, mainly the hypertonic saline (HS) test, and methacholine challenge test (MCT) versus ET in identifying EIB among non-athletic subjects. METHODS: We prospectively recruited subjects who did not have confirmed active asthma, but who reported exercise-induced dyspnoea. The participants underwent HS and ET on separate days within two weeks. MCT performed within one year were obtained retrospectively from medical records. The sensitivity, specificity, and accuracy of each diagnostic test were calculated using ET as the gold standard. RESULTS: We recruited 27 participants (mean age 20.6±2.5 years; 92.6% male). Five (18.5%) had a history of self-reported asthma prior to recruitment. Eleven participants (40.7%) had a positive ET test. The sensitivity, specificity and accuracy of HS in diagnosing EIB was 90.9%, 62.5% and 74.1%; while that of MCT was 88.9%, 83.3% and 85.7% respectively. Six subjects were positive to HS but had negative ET test. CONCLUSIONS: Both HS and MCT were found to be suitable alternatives to ET in screening for EIB in the non-athletic population in this pilot study. Further large scale studies are required to confirm this finding. These tests have the potential to replace ET for the diagnosis of EIB in centres without ET equipment or facilities.