22 research outputs found

    A method to increase reproducibility in adult ventricular myocyte sizing and flow cytometry: Avoiding cell size bias in single cell preparations.

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    RATIONALE:Flow cytometry (FCM) of ventricular myocytes (VMs) is an emerging technology in adult cardiac research that is challenged by the wide variety of VM shapes and sizes. Cellular variability and cytometer flow cell size can affect cytometer performance. These two factors of variance limit assay validity and reproducibility across laboratories. Washing and filtering of ventricular cells in suspension are routinely done to prevent cell clumping and minimize data variability without the appropriate standardization. We hypothesize that washing and filtering arbitrarily biases towards sampling smaller VMs than what actually exist in the adult heart. OBJECTIVE:To determine the impact of washing and filtering on adult ventricular cells for cell sizing and FCM. METHODS AND RESULTS:Left ventricular cardiac cells in single-cell suspension were harvested from New Zealand White rabbits and fixed prior to analysis. Each ventricular sample was aliquoted before washing or filtering through a 40, 70, 100 or 200Ī¼m mesh. The outcomes of the study are VM volume by Coulter Multisizer and light-scatter signatures by FCM. Data are presented as meanĀ±SD. Myocyte volumes without washing or filtering (NF) served as the "gold standard" within the sample and ranged from 11,017 to 46,926Ī¼m3. Filtering each animal sample through a 200Ī¼m mesh caused no variation in the post-filtration volume (1.01+0.01 fold vs. NF, n = 4 rabbits, p = 0.999) with an intra-assay coefficient of variation (%CV) of <5% for all 4 samples. Filtering each sample through a 40, 70 or 100Ī¼m mesh invariably reduced the post-filtration volume by 41Ā±10%, 9.0Ā±0.8% and 8.8Ā±0.8% respectively (n = 4 rabbits, p<0.0001), and increased the %CV (18% to 1.3%). The high light-scatter signature by FCM, a simple parameter for the identification of ventricular myocytes, was measured after washing and filtering. Washing discarded VMs and filtering cells through a 40 or 100Ī¼m mesh reduced larger VM by 46% or 11% respectively (n = 6 from 2 rabbits, p<0.001). CONCLUSION:Washing and filtering VM suspensions through meshes 100Ī¼m or less biases myocyte volumes to smaller sizes, excludes larger cells, and increases VM variability. These findings indicate that validity and reproducibility across laboratories can be compromised unless cell preparation is standardized. We propose no wash prior to fixation and a 200Ī¼m mesh for filtrations to provide a reproducible standard for VM studies using FCM

    Spending and procedural data on voluntary medical male circumcision

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    Introduction: Voluntary male medical circumcision (VMMC) reduces HIV acquisition by up to 60%. Kenya has successfully scaled up VMMC to an estimated 91% of eligible men and boys in certain regions. Given that funding toward VMMC is expected to decline in the coming years, it is important to identify what models of care are most appropriate and efficient as new cohorts of men become eligible for VMMC. To this end, we compared the costs of facility-based VMMC and one within a rapid results initiative (RRI), a public health service scheduled during school holidays to perform many procedures over a short period. Methods: We employed activity-based micro-costing to estimate the costs, from the implementer perspective, of facility-based VMMC and RRI-based VMMC conducted between October 2017 and September 2018 at 41 sites in Kisumu County, Kenya supported by the Family AIDS Care & Education Services (FACES). We conducted site visits and reviewed financial ledger and programmatic data to identify and quantify resources consumed and the number of VMMC procedures performed during routine care and RRIs. Ledger data were used to estimate fixed costs, recurring costs, and cost per circumcision (CPC) in United States dollar (USD). A sensitivity analysis was done to estimate CPC where we allocated 6 months of the ledger to facility-based and 6 months to RRI. Results: Overall, FACES spent 3,092,891towardVMMCservicesandperformed42,139proceduresduringthefundingyear.Thisincluded3,092,891 toward VMMC services and performed 42,139 procedures during the funding year. This included 2,644,910 in stable programmatic costs, 139,786procedurecosts,and139,786 procedure costs, and 308,195 for RRI-specific activities. Over the year, 49% (n=20,625) of procedures were performed as part of routine care and 51% (n=21,514) were performed during the RRIs. Procedures conducted during facility-based cost 99.35percircumcision,thoseconductedduringtheRRIscost99.35 per circumcision, those conducted during the RRIs cost 48.51 per circumcision, and according to our sensitivity analysis, CPC for facility-based ranges from 99.35to99.35 to 287.24 and for RRI costs ranged from 29.81to29.81 to 48.51. Conclusion: The cost of VMMC during the RRI was substantially lower than unit costs reported in previous costing studies. We conclude that circumcision campaigns, such as the RRI, offer an efficient and sustainable approach to VMMC.Funding provided by: University of California, San FranciscoCrossref Funder Registry ID: http://dx.doi.org/10.13039/100008069Award Number

    A method to increase reproducibility in adult ventricular myocyte sizing and flow cytometry: Avoiding cell size bias in single cell preparations.

    No full text
    RATIONALE:Flow cytometry (FCM) of ventricular myocytes (VMs) is an emerging technology in adult cardiac research that is challenged by the wide variety of VM shapes and sizes. Cellular variability and cytometer flow cell size can affect cytometer performance. These two factors of variance limit assay validity and reproducibility across laboratories. Washing and filtering of ventricular cells in suspension are routinely done to prevent cell clumping and minimize data variability without the appropriate standardization. We hypothesize that washing and filtering arbitrarily biases towards sampling smaller VMs than what actually exist in the adult heart. OBJECTIVE:To determine the impact of washing and filtering on adult ventricular cells for cell sizing and FCM. METHODS AND RESULTS:Left ventricular cardiac cells in single-cell suspension were harvested from New Zealand White rabbits and fixed prior to analysis. Each ventricular sample was aliquoted before washing or filtering through a 40, 70, 100 or 200Ī¼m mesh. The outcomes of the study are VM volume by Coulter Multisizer and light-scatter signatures by FCM. Data are presented as meanĀ±SD. Myocyte volumes without washing or filtering (NF) served as the "gold standard" within the sample and ranged from 11,017 to 46,926Ī¼m3. Filtering each animal sample through a 200Ī¼m mesh caused no variation in the post-filtration volume (1.01+0.01 fold vs. NF, n = 4 rabbits, p = 0.999) with an intra-assay coefficient of variation (%CV) of <5% for all 4 samples. Filtering each sample through a 40, 70 or 100Ī¼m mesh invariably reduced the post-filtration volume by 41Ā±10%, 9.0Ā±0.8% and 8.8Ā±0.8% respectively (n = 4 rabbits, p<0.0001), and increased the %CV (18% to 1.3%). The high light-scatter signature by FCM, a simple parameter for the identification of ventricular myocytes, was measured after washing and filtering. Washing discarded VMs and filtering cells through a 40 or 100Ī¼m mesh reduced larger VM by 46% or 11% respectively (n = 6 from 2 rabbits, p<0.001). CONCLUSION:Washing and filtering VM suspensions through meshes 100Ī¼m or less biases myocyte volumes to smaller sizes, excludes larger cells, and increases VM variability. These findings indicate that validity and reproducibility across laboratories can be compromised unless cell preparation is standardized. We propose no wash prior to fixation and a 200Ī¼m mesh for filtrations to provide a reproducible standard for VM studies using FCM
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