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1.
Biomed Instrum Technol ; 57(1): 31-39, 2023.
Article in English | MEDLINE | ID: mdl-37099598

ABSTRACT

Studies of healthcare providers doffing personal protective equipment, especially gloves, indicate that self-contamination does occur. Although generally this is not hazardous, working with particularly pathogenic organisms, such as Ebola virus and Clostridium difficile, can present a serious health risk. Decontaminating medical gloves before removal can reduce self-contamination and mitigate the spread of these types of pathogens. Also, in cases of extreme shortage, the Centers for Disease Control and Prevention (CDC) has specific recommendations for decontaminating gloves for extended use. Reuse of medical gloves is strongly discouraged by both the CDC and Food and Drug Administration. This work seeks to lay a foundation of testing to evaluate whether a decontamination method is compatible for a given glove type and material. Four potential methods of decontamination (commercial hand soap, alcohol-based hand sanitizer, commercial bleach, and quaternary ammonium solution) were tested on a variety of surgical and patient examination gloves. The method of barrier performance evaluation was ASTM D5151-19, Standard Test Method for Detection of Holes in Medical Gloves. Our results indicated that the performance of the gloves after treatment was highly dependent on the composition of the medical gloves. In general, the surgical gloves in this study performed better than the patient examination gloves, regardless of the material from which they were made. Specifically, vinyl examination gloves tended to have poorer performance. In this study, the number of gloves available to test were limited and therefore statistical significance is beyond the scope of this project.


Subject(s)
Decontamination , Hemorrhagic Fever, Ebola , Humans , Hemorrhagic Fever, Ebola/prevention & control , Personal Protective Equipment , Gloves, Protective , Health Personnel
2.
Nat Biotechnol ; 40(7): 1082-1092, 2022 07.
Article in English | MEDLINE | ID: mdl-35256815

ABSTRACT

Single-nuclei RNA sequencing characterizes cell types at the gene level. However, compared to single-cell approaches, many single-nuclei cDNAs are purely intronic, lack barcodes and hinder the study of isoforms. Here we present single-nuclei isoform RNA sequencing (SnISOr-Seq). Using microfluidics, PCR-based artifact removal, target enrichment and long-read sequencing, SnISOr-Seq increased barcoded, exon-spanning long reads 7.5-fold compared to naive long-read single-nuclei sequencing. We applied SnISOr-Seq to adult human frontal cortex and found that exons associated with autism exhibit coordinated and highly cell-type-specific inclusion. We found two distinct combination patterns: those distinguishing neural cell types, enriched in TSS-exon, exon-polyadenylation-site and non-adjacent exon pairs, and those with multiple configurations within one cell type, enriched in adjacent exon pairs. Finally, we observed that human-specific exons are almost as tightly coordinated as conserved exons, implying that coordination can be rapidly established during evolution. SnISOr-Seq enables cell-type-specific long-read isoform analysis in human brain and in any frozen or hard-to-dissociate sample.


Subject(s)
Brain , RNA , Alternative Splicing/genetics , Brain/metabolism , Exons/genetics , Humans , Protein Isoforms/genetics , RNA/genetics , Sequence Analysis, RNA
3.
Genome Biol ; 22(1): 109, 2021 04 16.
Article in English | MEDLINE | ID: mdl-33863344

ABSTRACT

BACKGROUND: Targeted sequencing using oncopanels requires comprehensive assessments of accuracy and detection sensitivity to ensure analytical validity. By employing reference materials characterized by the U.S. Food and Drug Administration-led SEquence Quality Control project phase2 (SEQC2) effort, we perform a cross-platform multi-lab evaluation of eight Pan-Cancer panels to assess best practices for oncopanel sequencing. RESULTS: All panels demonstrate high sensitivity across targeted high-confidence coding regions and variant types for the variants previously verified to have variant allele frequency (VAF) in the 5-20% range. Sensitivity is reduced by utilizing VAF thresholds due to inherent variability in VAF measurements. Enforcing a VAF threshold for reporting has a positive impact on reducing false positive calls. Importantly, the false positive rate is found to be significantly higher outside the high-confidence coding regions, resulting in lower reproducibility. Thus, region restriction and VAF thresholds lead to low relative technical variability in estimating promising biomarkers and tumor mutational burden. CONCLUSION: This comprehensive study provides actionable guidelines for oncopanel sequencing and clear evidence that supports a simplified approach to assess the analytical performance of oncopanels. It will facilitate the rapid implementation, validation, and quality control of oncopanels in clinical use.


Subject(s)
Biomarkers, Tumor , Genetic Testing/methods , Genomics/methods , Neoplasms/genetics , Oncogenes , DNA Copy Number Variations , Genetic Testing/standards , Genomics/standards , Humans , Molecular Diagnostic Techniques/methods , Molecular Diagnostic Techniques/standards , Mutation , Neoplasms/diagnosis , Polymorphism, Single Nucleotide , Reproducibility of Results , Sensitivity and Specificity
4.
Genome Biol ; 22(1): 111, 2021 04 16.
Article in English | MEDLINE | ID: mdl-33863366

ABSTRACT

BACKGROUND: Oncopanel genomic testing, which identifies important somatic variants, is increasingly common in medical practice and especially in clinical trials. Currently, there is a paucity of reliable genomic reference samples having a suitably large number of pre-identified variants for properly assessing oncopanel assay analytical quality and performance. The FDA-led Sequencing and Quality Control Phase 2 (SEQC2) consortium analyze ten diverse cancer cell lines individually and their pool, termed Sample A, to develop a reference sample with suitably large numbers of coding positions with known (variant) positives and negatives for properly evaluating oncopanel analytical performance. RESULTS: In reference Sample A, we identify more than 40,000 variants down to 1% allele frequency with more than 25,000 variants having less than 20% allele frequency with 1653 variants in COSMIC-related genes. This is 5-100× more than existing commercially available samples. We also identify an unprecedented number of negative positions in coding regions, allowing statistical rigor in assessing limit-of-detection, sensitivity, and precision. Over 300 loci are randomly selected and independently verified via droplet digital PCR with 100% concordance. Agilent normal reference Sample B can be admixed with Sample A to create new samples with a similar number of known variants at much lower allele frequency than what exists in Sample A natively, including known variants having allele frequency of 0.02%, a range suitable for assessing liquid biopsy panels. CONCLUSION: These new reference samples and their admixtures provide superior capability for performing oncopanel quality control, analytical accuracy, and validation for small to large oncopanels and liquid biopsy assays.


Subject(s)
Alleles , Biomarkers, Tumor , Gene Frequency , Genetic Testing/methods , Genetic Variation , Genomics/methods , Neoplasms/genetics , Cell Line, Tumor , DNA Copy Number Variations , Genetic Heterogeneity , Genetic Testing/standards , Genomics/standards , Humans , Neoplasms/diagnosis , Workflow
5.
Biomed Instrum Technol ; 54(2): 102-109, 2020.
Article in English | MEDLINE | ID: mdl-32186903

ABSTRACT

Effective personal protective equipment (PPE) is critical in preventing the spread of infectious diseases. Appropriate test systems and test soils are needed to adequately evaluate PPE. ASTM test method F903, which specifies the test method setup also used in ASTM F1670 and F1671, has been used for decades to test liquid (ASTM F1670) or viral (ASTM F1671) penetration resistance of PPE fabrics. However, an alteration of the bacteriophage propagation method detailed in the standard was necessary to obtain consistent titers of virus. In this study, modification of the nutrient broth provided consistently higher titers of virus and the use of the top agar in smaller increments prevented premature solidification. This study then compared the standard ASTM F1671 (using bacteriophage ϕχ174) with a modified dot-blot method to assess viral penetration of PPE materials. The results indicated that ASTM F1671 and the dot-blot apparatus methods were equivalent. The dot-blot method described here is less labor intensive and faster than the ASTM F1671 method. However, using the dot-blot system, which uses antibodies to detect the bacteriophage and signal amplification, does not indicate if virus viability or infectivity is retained, whereas the ASTM F1671 method indicates both. Nonetheless, the method presented in this investigation is a substantial improvement of a standard method for viral challenge testing of PPE materials.


Subject(s)
Personal Protective Equipment , Soil
6.
J Pain Symptom Manage ; 59(3): 709-716.e2, 2020 03.
Article in English | MEDLINE | ID: mdl-31877346

ABSTRACT

CONTEXT: Essential for adequate management of breakthrough cancer pain is a combination of accurate (re-)assessment and a personalized treatment plan. The Breakthrough Pain Assessment Tool (BAT) has been proven to be a brief, multidimensional, reliable, and valid questionnaire for the assessment of breakthrough cancer pain. OBJECTIVES: The aim of this study was to examine the validity and reliability of the Dutch Language version of the BAT (BAT-DL) in patients with cancer. METHODS: The BAT was forward-backward translated into the Dutch language. Thereafter, the psychometric properties of the BAT-DL were tested, that is factor structure, reliability (internal consistency and test-retest reliability), validity (content validity and construct validity), and the responsiveness to change. RESULTS: The BAT-DL confirmed the two-factor structure in 170 patients with cancer: pain severity/impact factor and pain duration/medication efficacy factor. The Cronbach's alpha coefficient was 0.72, and the intraclass correlation for the test-retest reliability was 0.81. The BAT-DL showed to be able to differentiate between different group of patients and correlated significantly with the Brief Pain Inventory. In addition, the BAT-DL was capable to detect clinically important changes over time. CONCLUSION: The BAT-DL is a valid and reliable questionnaire to assess breakthrough pain in Dutch patients with cancer and is a relevant questionnaire for daily practice.


Subject(s)
Breakthrough Pain , Neoplasms , Breakthrough Pain/diagnosis , Breakthrough Pain/drug therapy , Humans , Language , Neoplasms/complications , Neoplasms/diagnosis , Pain Measurement , Psychometrics , Reproducibility of Results , Surveys and Questionnaires
7.
J Mol Diagn ; 21(5): 808-823, 2019 09.
Article in English | MEDLINE | ID: mdl-31173928

ABSTRACT

Next-generation DNA sequencing is rapidly becoming an indispensable tool for genome-directed cancer diagnostics, but next-generation RNA sequencing (RNA-seq) is currently not standardly used in clinical diagnostics for expression assessment. However, multigene RNA diagnostic assays are used increasingly in the routine diagnosis of early-stage breast cancer. Two of the most widely used tests are currently available only as a central laboratory service, which limits their clinical use. We evaluated the use of RNA-seq as a decentralized method to perform such tests. The MammaPrint and BluePrint RNA-seq tests were found to be equivalent to the clinically validated microarray tests. The RNA-seq tests were highly reproducible when performed in different locations and were stable over time. The MammaPrint RNA-seq test was clinically validated. Our data demonstrate that RNA-seq can be used as a decentralized platform, yielding results substantially equivalent to results derived from the predicate diagnostic device.


Subject(s)
Biomarkers, Tumor/genetics , Breast Neoplasms/diagnosis , Breast Neoplasms/genetics , Gene Expression Profiling/methods , High-Throughput Nucleotide Sequencing/methods , Microarray Analysis/methods , Pathology, Molecular/methods , Biomarkers, Tumor/analysis , Breast Neoplasms/pathology , Female , Humans
8.
Biomed Instrum Technol ; 53(3): 196-201, 2019.
Article in English | MEDLINE | ID: mdl-31162954

ABSTRACT

Effective personal protective equipment (PPE) is critically important to preventing the spread of infectious diseases. Appropriate test systems and test soils are needed to adequately evaluate PPE. ASTM test method F903, which specifies the test method setup also used in ASTM F1670/F1670M-17a and ASTM F1671/F1671M-13, has been used for decades to test liquid penetration resistance of fabrics. All three standards require at least 60 mL of challenge liquid, such as synthetic blood solution (F1670) or bacteriophage in nutrient broth (F1671). The three ASTM test methods also are labor intensive and prone to exhibiting problems with leakage around the gaskets. Previous work comparing the F903 test apparatus with a modified dot-blot apparatus to evaluate the visual penetration of a blood test soil in series of commercially available gowns and drapes demonstrated that the methods are comparable and revealed that penetration through PPE material may depend on the test solution. The study described here evaluated a series of clinically relevant test soils (blood, vomit, urine, and feces) in penetration of PPE garments using the modified dot-blot apparatus. The results indicated that a vomit test soil penetrates PPE material more often than blood, urine, or fecal test soils and that the blood test soil has the least number of PPE failures. Incorporating clinically relevant, chemically defined test soils to evaluate PPE material should be considered to protect healthcare workers and reduce the spread of infectious material.


Subject(s)
Personal Protective Equipment , Soil , Health Personnel , Protective Clothing
9.
J Test Eval ; 48(1)2019 Mar 07.
Article in English | MEDLINE | ID: mdl-36147246

ABSTRACT

Personal protective equipment (PPE), such as gowns used in the latest Ebola outbreak in Western Africa, are critical in preventing the spread of deadly diseases. Appropriate test systems and test soils are needed to adequately evaluate PPE. ASTM F903, Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Liquid, has been used for decades to test fabrics' resistance to liquid penetration. However, this test apparatus requires at least 60 mL of test solutions, is labor intensive, and has problems with leakage around the gaskets. We compared the F903 test apparatus to a modified dot-blot apparatus to evaluate the visual penetration of a blood test soil. A series of commercially available gowns and drapes were tested in each apparatus. Using blood test soil at 2 psi, there was no statistically significant difference between the two methods except for in one gown. By comparing this gown in the ASTM test apparatus with and without a screen, the particular screen selected did not account for the difference between the dot-blot and F903 apparatuses; however, it is conceivable that a particular screen/fabric combination could account for this difference. The modified dot-blot apparatus was evaluated using three different test solutions: blood, vomit, and a labeled protein (goat anti-rabbit immunoglobulin G-horseradish peroxidase [GaR IgG-HRP]) in a blood test soil solution. This testing revealed significant difference in penetration for some of the PPE garments. The modified dot-blot had several large advantages over the ASTM apparatus-over six times less specimen volume and no edge or gasket leakage. In addition, nitrocellulose can be easily incorporated into the modified dot-blot apparatus, enabling the trapping of viruses and proteins that penetrate PPE-thus permitting the use of antibodies to quickly and sensitively detect penetration.

10.
J Biomed Mater Res B Appl Biomater ; 107(5): 1706-1710, 2019 07.
Article in English | MEDLINE | ID: mdl-30388312

ABSTRACT

Reusable medical devices (RMDs) must be reprocessed between uses to render them safe for each use and each patient. Cleaning used devices removes organic and inorganic soil making them either safe for reuse or ready for disinfection/sterilization depending on the device. Although cleaning is an important step in a RMD's life cycle, it is not always a priority during device design. In addition, when performing cleaning validation, it is recommended that the manufacturer takes into consideration, what the most appropriate or worst case conditions are in terms of type of soil or the presence of bacteria. This study compared the ability of three different cleaning/disinfecting agents (water, alcohol, and bleach) to remove bacteria and fecal test soil from two different polymers: polypropylene and ultrahigh molecular weight polyethylene (UHMWPE) with two different roughness. There were some differences in the effects of the cleaning/disinfecting agents, the materials, and the roughness depending on the particular circumstances. However, the most consistent effect on the removal of bacteria was the presence of soil, which protected the bacteria from being removed. Conversely, the presence of bacteria played little role in the removal of soil. Although the interactions between material type and roughness, soil type, and bacteria are complicated, they should be taken into account during device design and reprocessing validation to create a device that is easy and safe to use. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1706-1710, 2019.


Subject(s)
Bacterial Infections/prevention & control , Clostridioides difficile/drug effects , Disinfectants/chemistry , Disinfectants/metabolism , Fecal Incontinence/prevention & control , Polypropylenes/chemistry , Bleaching Agents/chemistry , Bleaching Agents/metabolism , Decontamination/instrumentation , Decontamination/methods , Disinfection , Equipment Design/instrumentation , Equipment Design/methods , Equipment Reuse , Equipment Safety , Ethanol/chemistry , Ethanol/metabolism , Humans , Sterilization
11.
Mol Ther ; 26(10): 2431-2442, 2018 10 03.
Article in English | MEDLINE | ID: mdl-30005866

ABSTRACT

Genome-editing technologies are currently being translated to the clinic. However, cellular effects of the editing machinery have yet to be fully elucidated. Here, we performed global microarray-based gene expression measurements on human CD34+ hematopoietic stem and progenitor cells that underwent editing. We probed effects of the entire editing process as well as each component individually, including electroporation, Cas9 (mRNA or protein) with chemically modified sgRNA, and AAV6 transduction. We identified differentially expressed genes relative to control treatments, which displayed enrichment for particular biological processes. All editing machinery components elicited immune, stress, and apoptotic responses. Cas9 mRNA invoked the greatest amount of transcriptional change, eliciting a distinct viral response and global transcriptional downregulation, particularly of metabolic and cell cycle processes. Electroporation also induced significant transcriptional change, with notable downregulation of metabolic processes. Surprisingly, AAV6 evoked no detectable viral response. We also found Cas9/sgRNA ribonucleoprotein treatment to be well tolerated, in spite of eliciting a DNA damage signature. Overall, this data establishes a benchmark for cellular tolerance of CRISPR/Cas9-AAV6-based genome editing, ensuring that the clinical protocol is as safe and efficient as possible.


Subject(s)
Genetic Therapy , Genetic Vectors/genetics , Microarray Analysis/methods , Parvovirinae/genetics , Antigens, CD34/genetics , CRISPR-Associated Protein 9/genetics , CRISPR-Cas Systems/genetics , Dependovirus , Electroporation , Gene Editing/methods , Gene Expression Regulation/genetics , Genetic Vectors/therapeutic use , Hematopoietic Stem Cell Transplantation , Hematopoietic Stem Cells/drug effects , Humans , Stem Cells/drug effects
12.
Methods Mol Biol ; 1783: 81-104, 2018.
Article in English | MEDLINE | ID: mdl-29767358

ABSTRACT

Gene expression profiling of samples from biobanks requires a method that can be used with intact as well as partially degraded RNA. High throughput applications can benefit from reducing the number of processing steps including eliminating the poly(A) selection and ribosomal depletion steps. When performing targeted capture, we have found that we can eliminate the upfront poly(A) selection/ribosomal depletion steps that cause bias in standard mRNA-Seq workflows. This target enrichment solution allows for whole transcriptome or customized content to characterize differential gene expression patterns (especially for mid/low level transcripts). Protocol modifications to the Agilent Strand-Specific RNA Library Prep kit resulted in a new workflow called "RNA Direct" that generates RNA-Seq data with minimal ribosomal contamination and good sequencing coverage. Using RNA isolated from a set of matched samples including fresh frozen (FF) or formalin-fixed, paraffin-embedded (FFPE) from tumor/normal tissues we generated high-quality data using a protocol that does not require upfront ribosomal depletion or poly(A) selection. Using SureSelectXT RNA Direct protocol (RNA Direct) workflow, we found transcripts to be upregulated or downregulated to similar degrees with similar confidence levels in both the FF and FFPE samples, demonstrating the utility for meaningful gene expression studies with biobank samples of variable quality.


Subject(s)
Biomarkers/analysis , Gene Expression Profiling/methods , High-Throughput Nucleotide Sequencing/methods , Neoplasms/genetics , RNA/genetics , Sequence Analysis, RNA/methods , Transcriptome , Gene Library , Humans , Paraffin Embedding , RNA/isolation & purification , Tissue Fixation , Workflow
13.
Acta Biomater ; 72: 424-433, 2018 05.
Article in English | MEDLINE | ID: mdl-29597023

ABSTRACT

Although nitinol is widely used in percutaneous cardiovascular interventions, a causal relationship between nickel released from implanted cardiovascular devices and adverse systemic or local biological responses has not been established. The objective of this study was to investigate the relationship between nitinol surface processing, in-vivo nickel release, and biocompatibility. Nitinol stents manufactured using select surface treatments were implanted into the iliac arteries of minipigs for 6 months. Clinical chemistry profile, complete blood count, serum and urine nickel analyses were performed periodically during the implantation period. After explant, stented arteries were either digested and analyzed for local nickel concentration or fixed and sectioned for histopathological analysis of stenosis and inflammation within the artery. The results indicated that markers for liver and kidney function were not different than baseline values throughout 180 days of implantation regardless of surface finish. In addition, white blood cell, red blood cell, and platelet counts were similar to baseline values for all surface finishes. Systemic nickel concentrations in serum and urine were not significantly different between processing groups and comparable to baseline values during 180 days of implantation. However, stents with non-optimized surface finishing had significantly greater nickel levels in the surrounding artery compared to polished stents. These stents had increased stenosis with potential for local inflammation compared to polished stents. These findings demonstrate that proper polishing of nitinol surfaces can reduce in-vivo nickel release locally, which may aid in minimizing adverse inflammatory reactions and restenosis. STATEMENT OF SIGNIFICANCE: Nitinol is a commonly used material in cardiovascular medical devices. However, relationships between nitinol surface finishing, in-vivo metal ion release, and adverse biological responses have yet to be established. We addressed this knowledge gap by implanting single and overlapped nitinol stents with different surface finishes to assess systemic impact on minipigs (i.e. serum and urine nickel levels, liver and kidney function, immune and blood count) over the 6 month implantation period. In addition, nickel levels and histopathology in stented arteries were analyzed on explant to determine relationships between surface processing and local adverse tissue reactions. The findings presented here highlight the importance of surface processing on in-vivo nickel release and subsequent impact on local biological response for nitinol implants.


Subject(s)
Alloys , Graft Occlusion, Vascular/prevention & control , Nickel , Stents , Alloys/pharmacokinetics , Alloys/pharmacology , Animals , Female , Graft Occlusion, Vascular/metabolism , Graft Occlusion, Vascular/pathology , Nickel/pharmacokinetics , Nickel/pharmacology , Surface Properties , Swine , Swine, Miniature , Time Factors
14.
J Biomed Mater Res B Appl Biomater ; 106(6): 2455-2463, 2018 08.
Article in English | MEDLINE | ID: mdl-29226556

ABSTRACT

Ethylene oxide (EO) gas is commonly used to sterilize medical devices. Bioavailable residual EO, however, presents a significant toxicity risk to patients. Residual EO is assessed using international standards describing extraction conditions for different medical device applications. We examine a series of polymers and explore different extraction conditions to determine residual EO. Materials were sterilized with EO and exhaustively extracted in water, in one of three organic solvents, or in air using thermal desorption. The EO exhaustively extracted varies significantly and is dictated by two factors: the EO that permeates the material during sterilization; and the effectiveness of the extraction protocol in flushing residual EO from the material. Extracted EO is maximized by a close matches between Hildebrand solubility parameters δpolymer , δEO , and δsolvent . There remain complexities to resolve, however, because maximized EO uptake and detection are accompanied by great variability. These observations may inform protocols for material selection, sterilization, and EO extraction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2455-2463, 2018.


Subject(s)
Equipment and Supplies , Ethylene Oxide/analysis , Sterilization/methods , Ethylene Oxide/chemistry
15.
Am J Infect Control ; 45(7): 793-798, 2017 Jul 01.
Article in English | MEDLINE | ID: mdl-28359612

ABSTRACT

BACKGROUND: One-way valves used in day use devices (used on multiple patients throughout a day without reprocessing between patients) are intended to reduce the potential for cross-contamination between patients resulting from the backflow of patient fluids. One-way valves are typically designed to withstand high levels of back pressure before failure; however, they may not be explicitly designed as a means of infection control as used in medical device applications. METHODS: Five different medical grade one-way valves were placed in low pressure configurations. After flushing in the intended direction of flow, bacteriophage, bacteria, or dye was placed patient side for 24 hours. The upstream device side of the valve was then evaluated for microbial growth or presence of visible dye. RESULTS: Leakage (ie, backflow) of the microorganisms occurred with a variety of one-way valve designs across a range of fluid properties tested. CONCLUSIONS: This study describes testing of the one-way valves (component-level testing) for the potential of cross-contamination. Although day use medical device systems may use numerous other factors to prevent patient cross-contamination, this work demonstrates that one-way valves themselves may not prevent leakage of contaminated fluid if the fluid is able to reach the upstream side of the one-way valve.


Subject(s)
Cross Infection/prevention & control , Equipment and Supplies , Infection Control/instrumentation , Humans
16.
Pharm Dev Technol ; 22(1): 35-44, 2017 Feb.
Article in English | MEDLINE | ID: mdl-26895348

ABSTRACT

Potential connections between release profiles and solvent evaporation rates alongside polymer chemistry were elucidated for the release of tetracycline hydrochloride from two different poly (d, l-lactide-co-glycolide) (PLGA) film matrices containing high drug fractions (50%, 30%, and 15%), and prepared at two distinct solvent evaporation rates. At highest tetracycline concentrations (50%), (i) the early release rates were ≤0.5 µg/min in all cases; (ii) release was linear from systems fabricated with lower lactic content and slower solvent evaporation rate and bimodal from systems fabricated with higher lactic content and faster evaporation rate; (iii) surface fractions covered by the drug were similar at both evaporation rates for 85:15 PLGA but very different for 50:50 PLGA, leading to unexpectedly reduced early release from 50:50 PLGA than from 85:15 PLGA when both the matrices were fabricated using a slower evaporation rate. These features remained unaffected in case of low drug concentration. Results suggested that during the formation of the drug-polymer microstructure, the combined effect of polymer chemistry and solvent evaporation rate sets apart the surface characteristics and the initial release profiles of systems containing high drug fraction, and an appropriate combination of these parameters may be utilized to control the early stage of drug release.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Delayed-Action Preparations/chemistry , Drug Liberation , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Tetracycline/administration & dosage , Anti-Bacterial Agents/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Solubility , Solvents/chemistry , Tetracycline/chemistry , Volatilization
17.
Am J Infect Control ; 45(2): 194-196, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27776820

ABSTRACT

Cleaning reusable medical devices removes organic and inorganic soil, which allows for effective disinfection and sterilization. However, it is not always clear what variables to consider when validating cleaning. This study compared the ability of 3 different cleaning agents (ie, water, alcohol, and bleach) to remove bacteria (ie, vegetative and spores) and artificial blood test soil from 2 common device materials: polypropylene and ultra-high-molecular-weight polyethylene. There was a complex interaction between bacteria, soil, and surface roughness.


Subject(s)
Bacteria/isolation & purification , Equipment Contamination , Equipment and Supplies , Hematologic Tests , Surface Properties , Decontamination/methods , Disinfection/methods , Humans
18.
BMC Biotechnol ; 16(1): 54, 2016 Jun 24.
Article in English | MEDLINE | ID: mdl-27342544

ABSTRACT

BACKGROUND: Highly multiplexed assays for quantitation of RNA transcripts are being used in many areas of biology and medicine. Using data generated by these transcriptomic assays requires measurement assurance with appropriate controls. Methods to prototype and evaluate multiple RNA controls were developed as part of the External RNA Controls Consortium (ERCC) assessment process. These approaches included a modified Latin square design to provide a broad dynamic range of relative abundance with known differences between four complex pools of ERCC RNA transcripts spiked into a human liver total RNA background. RESULTS: ERCC pools were analyzed on four different microarray platforms: Agilent 1- and 2-color, Illumina bead, and NIAID lab-made spotted microarrays; and two different second-generation sequencing platforms: the Life Technologies 5500xl and the Illumina HiSeq 2500. Individual ERCC controls were assessed for reproducible performance in signal response to concentration among the platforms. Most demonstrated linear behavior if they were not located near one of the extremes of the dynamic range. Performance issues with any individual ERCC transcript could be attributed to detection limitations, platform-specific target probe issues, or potential mixing errors. Collectively, these pools of spike-in RNA controls were evaluated for suitability as surrogates for endogenous transcripts to interrogate the performance of the RNA measurement process of each platform. The controls were useful for establishing the dynamic range of the assay, as well as delineating the useable region of that range where differential expression measurements, expressed as ratios, would be expected to be accurate. CONCLUSIONS: The modified Latin square design presented here uses a composite testing scheme for the evaluation of multiple performance characteristics: linear performance of individual controls, signal response within dynamic range pools of controls, and ratio detection between pairs of dynamic range pools. This compact design provides an economical sample format for the evaluation of multiple external RNA controls within a single experiment per platform. These results indicate that well-designed pools of RNA controls, spiked into samples, provide measurement assurance for endogenous gene expression studies.


Subject(s)
Gene Expression Profiling/standards , High-Throughput Nucleotide Sequencing/standards , RNA/genetics , RNA/standards , Sequence Analysis, RNA/standards , Algorithms , Gene Expression Profiling/methods , High-Throughput Nucleotide Sequencing/methods , Humans , Reference Values , Reproducibility of Results , Sensitivity and Specificity
19.
Am J Infect Control ; 44(3): 304-10, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26589998

ABSTRACT

BACKGROUND: This study examined the effectiveness of commercially available disinfecting wipes and cosmetic wipes in disinfecting pulse oximeter sensors contaminated with pathogenic bacterial surrogates. METHODS: Surrogates of potential biological warfare agents and bacterial pathogens associated with hospital-acquired infections (HAIs) were spotted on test surfaces, with and without an artificial test soil (sebum), allowed to dry, and then cleaned with different commercially available cleaning and disinfecting wipes or sterile gauze soaked in water, bleach (diluted 1:10), or 70% isopropanol. The percentage of microbial survival and an analytical estimation of remaining test soil on devices were determined. RESULTS: Wipes containing sodium hypochlorite as the active ingredient and gauze soaked in bleach (1:10) were the most effective in removing both vegetative bacteria and spores. In the presence of selective disinfectants, sebum had a protective effect on vegetative bacteria, but not on spores. CONCLUSIONS: The presence of sebum reduces the cleaning efficiency of some commercially available wipes for some select microbes. Various commercial wipes performed significantly better than the designated cleaning agent (70% isopropanol) in disinfecting the oximetry sensor. Cosmetic wipes were not more effective than the disinfecting wipes in removing sebum.


Subject(s)
Bacteria/isolation & purification , Disinfection/methods , Equipment and Supplies/microbiology , Humans , Oximetry
20.
Am J Infect Control ; 43(12): 1331-5, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26654235

ABSTRACT

BACKGROUND: Nosocomial infections are a serious problem in health care facilities. Bacteria can be transferred from patient to patient via contaminated reusable medical devices and equipment. METHODS: An anesthesia machine and objects representative of smooth and ridged machine knobs were contaminated with Staphylococcus aureus, Bacillus atrophaeus spores, and Clostridium sporogenes spores. The ability of 5 commercially available cleaning-disinfecting wipes to remove bacteria was compared with gauze soaked with water or bleach. Gauze soaked with water was used to determine the optimal wetness for bacteria removal, which was then used to evaluate the efficacy of the wipe ingredients. RESULTS: All of the wipes cleaned the device surfaces significantly better than the no wipe control. Some wipes performed equally well as gauze with water, whereas others performed worse. Overall, the wipe containing sodium hypochlorite was the most effective at removing bacteria. When the wipe ingredients were re-evaluated using the determined optimal wipe wetness on gauze, their effectiveness at cleaning S aureus, but not spores, significantly improved. CONCLUSION: Physically removing bacteria from device surfaces with water was often as effective as the cleaning-disinfecting wipes. Of the wipe active ingredients evaluated, sodium hypochlorite was the most effective overall. The wetness of the wipes may also play a role in their effectiveness.


Subject(s)
Bacillus/isolation & purification , Clostridium/isolation & purification , Decontamination/methods , Disinfection/methods , Equipment and Supplies/microbiology , Staphylococcus aureus/isolation & purification , Pilot Projects
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