An integrated quantification method to increase the precision, robustness, and resolution of protein measurement in human plasma samples.

BACKGROUND: Current quantification methods for mass spectrometry (MS)-based proteomics either do not provide sufficient control of variability or are difficult to implement for routine clinical testing. RESULTS: We present here an integrated quantification (InteQuan) method that better controls pre-analytical and analytical variability than the popular quantification method using stable isotope-labeled standard peptides (SISQuan). We quantified 16 lung cancer biomarker candidates in human plasma samples in three assessment studies, using immunoaffinity depletion coupled with multiple reaction monitoring (MRM) MS. InteQuan outperformed SISQuan in precision in all three studies and tolerated a two-fold difference in sample loading. The three studies lasted over six months and encountered major changes in experimental settings. Nevertheless, plasma proteins in low ng/ml to low µg/ml concentrations were measured with a median technical coefficient of variation (CV) of 11.9% using InteQuan. The corresponding median CV using SISQuan was 15.3% after linear fitting. Furthermore, InteQuan surpassed SISQuan in measuring biological difference among clinical samples and in distinguishing benign versus cancer plasma samples. CONCLUSIONS: We demonstrated that InteQuan is a simple yet robust quantification method for MS-based quantitative proteomics, especially for applications in biomarker research and in routine clinical testing.

Modification of Major Contributors Responsible for Latrine Malodor on Exposure to Hypochlorous Acid: The Potential for Simultaneously Impacting Odor and Infection Hazards to Encourage Latrine Use.

Open defecation remains a common practice in developing countries and leads to high incidence and prevalence of acute gastroenteritis, which is most often caused by human noroviruses (human NoV). Encouraging the use of toilets and pit latrines is one method of improving sanitation; however, it is often hindered by not only cultural traditions but also from a reluctance to use latrines and toilets due to their odor and impression of uncleanliness. In an effort to establish new means to encourage toilet and latrine use, laboratory experiments tested the ability of hypochlorous acid (HOCl) to modify the malodorous compounds identified in the air in latrines in developing countries (indole, p-cresol, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and butyric acid) and inactivate MS2 bacteriophage, a surrogate for human NoV. After 5 minutes, > 94% of indole, p-cresol, DMDS, and DMTS was modified as determined by high-pressure liquid chromatography in the presence of 100 ppm HOCl. A log10 reduction value (LRV) greater than 6 was seen for MS2 bacteriophage after 5 minutes of exposure to 100 ppm HOCl in solution. Sensory studies indicated that there was a significant difference (P ≤ 0.05) between the untreated and HOCl-treated samples for all five malodorous compounds tested. The findings suggest that introduction of HOCl into the headspace air could encourage latrine and toilet use. Optimization of HOCl dosing in air to accomplish both odor control and reduction of infectious hazards is worthy of further study.

The efficacy of link items in the construction of a numeracy achievement scale--from kindergarten to year 6.

A large-scale numeracy research project was commissioned by the Australian Government, involving 4732 Australian students from 91 NSW primary schools. Rasch analysis was applied in the construction of a Numeracy Achievement Scale (NAS) in order to measure numeracy growth. Following trialling, a pool of 244 items was developed to assess number, space and measurement concepts. Link items were included in test forms within year levels and across adjacent year levels to enable linking of the forms and the construction of a scale spanning Kindergarten to Year 6 (5 to 13 years of age). However, results from the scaling were not consistent with expectations of increases in student abilities or item difficulties across year levels. Differential item functioning determined the problematic role of link items across year levels. After a different set of items was used for linking test forms, the results were consistent with expectations. A key finding was that items used to link forms must not exhibit differential item functioning across those levels.

Comparison of Intraoperative Outcomes between Single-incision Robotic Cholecystectomy and Multi-incision Robotic Cholecystectomy.

Background The aim of this study was to evaluate the differences in the key surgical factors for single-incision robotic cholecystectomy (SIRC) and multi-incision robotic cholecystectomy (MIRC). Methods A retrospective data review from August 2013 to April 2018 consisting of 104 SIRC and 105 MIRC cases was done considering factors including patient gender, age, operating time (skin incision to skin closure), robotic console time (docking to undocking), the preoperative diagnosis for surgery, any complications in surgery, length of stay (LOS), and estimated blood loss (EBL). Procedures with conversion away from original robotic cholecystectomy approach were excluded. Chi-square analysis (p-value: 0.05) was run between the two data sets. Results A total of 209 robotic cholecystectomy cases were reviewed since 2013. We found significantly less time with single-incision compared to multi-incision (single incision = 94.0 minutes, multi-incision = 99.9 minutes, p = 0.016) and EBL (single-incision = 11.52 mL, multi-incision = 17.17 mL, p = 0.004). There was no significant difference in age or robotic console time. The most common indication was symptomatic cholelithiasis overall, with equal cases of dyskinesia in single-incision approach, although there was no significant difference in indication between the two approaches. Intraoperatively, there was marginally significant use of irrigation in multi-incision (multi-incision 45 [42.9%], single-incision 31 [29.8%], p = 0.0499) and no difference in Firefly, perforation, or intraoperative cholangiogram use. LOS results showed significant decreased stay in SIRC cases (single-incision 84 outpatients [80.8%], multi-incision 75 [71.4%]; p = 0.0379). Conclusions SIRC and MIRC are both safe and feasible ways to remove the inflamed/dysfunctional gallbladder. SIRC is associated with less operative time, less blood loss, and shorter hospital stay.

Spinal cord injury without radiographic abnormality in a 4-year-old child: hypoperfusion injury or direct trauma?

Spinal cord injury without radiographic abnormality is uncommon even in major paediatric trauma. A case is described of a 4-year-old girl sustaining multiple injuries from blunt trauma including spinal cord injury without radiographic abnormality. She was profoundly shocked with extensive thoracic, abdominal and pelvic injuries. An MRI performed 8 days after injury showed an ischaemic area from T8 to L2 consistent with hypoperfusion. Various possible aetiologies exist, including distraction, hyperflexion, hyperextension and ischaemic spinal cord damage. In this case the likely cause was spinal ischaemia. The anterior spinal and two posterior spinal arteries supply the spinal cord. The aorta feeds these superiorly via the subclavian and vertebral arteries, and inferiorly via the radicular arteries. Injury may tear these conduit arteries from the aorta causing cord ischaemia. This is important in the thoracolumbar area where the radicular artery of Adamkewicz supplies a large area of the spinal cord. The artery of Adamkewicz may have been interrupted directly by blunt trauma. The other cause of ischaemia is the systemic hypoperfusion sustained owing to profound hypovolaemia, which could also correlate with the child's reported transient blindness. Treatment and prognosis of spinal cord injury without radiographic abnormality are considered.