Integrated systems for rapid point of care (PoC) blood cell analysis

Counting the different subpopulations of cells in a fingerprick of human blood is important for a number of clinical point-of-care (PoC) applications. It is a challenge to demonstrate the integration of sample preparation and detection techniques in a single platform. In this paper we demonstrate a generic microfluidic platform that combines sample processing and characterisation and enumeration in a single, integrated system. Results of microfluidic 3-part differential leukocyte (granulocyte, lymphocyte and monocyte) counts, together with erythrocyte and thrombocyte (platelet) counts, in human blood are shown and corroborated with results from hospital clinical laboratory analysis

A Systematic Evaluation of the Impact of STRICTA and CONSORT Recommendations on Quality of Reporting for Acupuncture Trials

Background: We investigated whether there had been an improvement in quality of reporting for randomised controlled trials of acupuncture since the publication of the STRICTA and CONSORT statements. We conducted a before-and-after study, comparing ratings for quality of reporting following the publication of both STRICTA and CONSORT recommendations. Methodology and Principal Findings: Ninety peer reviewed journal articles reporting the results of acupuncture trials were selected at random from a wider sample frame of 266 papers. Papers published in three distinct time periods (1994–1995, 1999–2000 and 2004–2005) were compared. Assessment criteria were developed directly from CONSORT and STRICTA checklists. Papers were independently assessed for quality of reporting by two assessors, one of whom was blind to information which could have introduced systematic bias (e.g. date of publication). We detected a statistically significant increase in the reporting of CONSORT items for papers published in each time period measured. We did not, however, find a difference between the number of STRICTA items reported in journal articles published before and 3 to 4 years following the introduction of STRICTA recommendations. Conclusions and Significance: The results of this study suggest that general standards of reporting for acupuncture trials have significantly improved since the introduction of the CONSORT statement in 1996, but that quality in reporting detail

A blood atlas of COVID-19 defines hallmarks of disease severity and specificity.

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19

Non-invasive monitoring of brain tissue temperature by near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) is a non-invasive technique that is established as a research tool with which to study tissue oxygenation and haemodynamics, particularly in infant brains. In studies of oxygenation, NIRS relies on the oxygen-dependence of the haemoglobin spectrum to determine blood oxygen saturation. Similarly, the temperature- dependence of the tissue water absorption spectrum, due to changes in intermolecular hydrogen bonding, could act as an endogenous indicator of tissue temperature. This thesis describes the development of a methodology to determine in vivo tissue temperature using NIRS, based on the temperature response of the NIR water spectrum. One particular application of this technique is monitoring cerebral temperature in infants suffering from birth asphyxia, a condition in which the brain is deprived of oxygen. It has been shown that cooling the brain by a few degrees has a neuroprotective effect and the potential to prevent long-term damage. In order to assess the efficacy of mild hypothermia, brain temperature must be monitored continuously and non-invasively during the treatment, which is in principle possible with NIRS. Experiments have been performed to accurately characterise the temperature-dependence (in the clinical range) of the NIR water absorption spectrum between 650 and 1050 nm. Measurements of absorption are calibrated against temperature using a range of multivariate fitting techniques. In order to determine tissue temperature from the calibration of the water spectrum, the contribution of absorption to in vivo NIRS measurements must be separated from that of light scattering. Furthermore, absorption due to water must be extracted from the total absorption, which contains contributions from oxy- and deoxyhaemoglobin. A number of different approaches have been explored, including second derivative spectroscopy, non-linear diffusion theory modelling and spatially-resolved techniques. The performance of the tissue prediction algorithms are investigated using temperature-resolved measurements of a tissue phantom and ex vivo and in vivo tissues

Comparison of venous and capillary differential leukocyte counts using a standard hematology analyzer and a novel microfluidic impedance cytometer

Capillary blood sampling has been identified as a potentially suitable technique for use in diagnostic testing of the full blood count (FBC) at the point-of-care (POC), for which a recent need has been highlighted. In this study we assess the accuracy of capillary blood counts and evaluate the potential of a miniaturized cytometer developed for POC testing. Differential leukocyte counts in the normal clinical range from fingerprick (capillary) and venous blood samples were measured and compared using a standard hematology analyzer. The accuracy of our novel microfluidic impedance cytometer (MIC) was then tested by comparing same-site measurements to those obtained with the standard analyzer. The concordance between measurements of fingerprick and venous blood samples using the standard hematology analyzer was high, with no clinically relevant differences observed between the mean differential leukocyte counts. Concordance data between the MIC and the standard analyzer on same-site measurements presented significantly lower leukocyte counts determined by the MIC. This systematic undercount was consistent across the measured (normal) concentration range, suggesting that an internal correction factor could be applied. Differential leukocyte counts obtained from fingerprick samples accurately reflect those from venous blood, which confirms the potential of capillary blood sampling for POC testing of the FBC. Furthermore, the MIC device demonstrated here presents a realistic technology for the future development of FBC and related tests for use at the site of patient car

Microfluidic impedance cytometry of tumour cells in blood

The dielectric properties of tumour cells are known to differ from normal blood cells, and this difference can be exploited for label-free separation of cells. Conventional measurement techniques are slow and cannot identify rare circulating tumour cells (CTCs) in a realistic timeframe. We use high throughput single cell microfluidic impedance cytometry to measure the dielectric properties of the MCF7 tumour cell line (representative of CTCs), both as pure populations and mixed with whole blood. The data show that the MCF7 cells have a large membrane capacitance and size, enabling clear discrimination from all other leukocytes. Impedance analysis is used to follow changes in cell viability when cells are kept in suspension, a process which can be understood from modelling time-dependent changes in the dielectric properties (predominantly membrane conductivity) of the cells. Impedance cytometry is used to enumerate low numbers of MCF7 cells spiked into whole blood. Chemical lysis is commonly used to remove the abundant erythrocytes, and it is shown that this process does not alter the MCF7 cell count or change their dielectric properties. Combining impedance cytometry with magnetic bead based antibody enrichment enables MCF7 cells to be detected down to 100 MCF7 cells in 1 ml whole blood, a log 3.5 enrichment and a mean recovery of 92%. Microfluidic impedance cytometry could be easily integrated within complex cell separation systems for identification and enumeration of specific cell types, providing a fast in-line single cell characterisation method

HACASE: a simple and versatile framework for session design and delivery

We have developed a simple framework, HACASE, for session design and delivery, based on established educational principles such as constructive alignment. The HACASE framework was primarily designed for new educators, but can also be used by experienced educators. Sessions designed using HACASE can be delivered to students, colleagues, patients and their families. Its versatility and sound educational foundations make it appropriate for single sessions, through to workshops, modules and beyond