Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Hall EM [original query] |
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Phosphine exposure among emergency responders - Amarillo, Texas, January 2017
Hall EM , Patel K , Victory KR , Calvert GM , Nogueira LM , Bojes HK . MMWR Morb Mortal Wkly Rep 2018 67 (13) 387-389 Phosphine is a highly toxic gas that forms when aluminum phosphide, a restricted-use pesticide* typically used in agricultural settings, reacts with water. Acute exposure can lead to a wide range of respiratory, cardiovascular, and gastrointestinal symptoms, and can be fatal (1). On January 2, 2017, the Texas Department of State Health Services (DSHS) was notified by the Texas Panhandle Poison Center of an acute phosphine exposure incident in Amarillo, Texas. DSHS investigated potential occupational phosphine exposures among the 51 on-scene emergency responders; 40 (78.4%) did not use respiratory protection during response operations. Fifteen (37.5%) of these 40 responders received medical care for symptoms or as a precaution after the incident, and seven (17.5%) reported new or worsening symptoms consistent with phosphine exposure within 24 hours of the incident. Emergency response organizations should ensure that appropriate personal protective equipment (PPE) is used during all incidents when an unknown hazardous substance is suspected. Additional evaluation is needed to identify targeted interventions that increase emergency responder PPE use during this type of incident. |
Glucose-6-phosphate dehydrogenase enzyme stability in filter paper dried blood spots
Flores SR , Hall EM , De Jesus VR . Clin Biochem 2017 50 (15) 878-881 OBJECTIVE: Prior to initial distribution of Glucose-6-phosphate dehydrogenase (G6PD) proficiency testing (PT) materials, we evaluated G6PD enzyme stability in dried blood spots (DBS) under various temperature and humidity environments to develop storage and usage guidelines for our new materials. DESIGN & METHODS: We prepared fresh G6PD-normal DBS materials and conducted stability evaluations of daily use and short and long-term storage under various temperature and humidity environments. RESULTS: G6PD DBS PT materials retained 92% of initial activity after 30days of use at 4 degrees C. Materials stored at -20 degrees C and 4 degrees C with desiccant for 30days retained 95% and 90% of initial activity, respectively. When stored for one year at -20 degrees C or six months at 4 degrees C specimens retained >90% of initial activity. Specimens stored at 37 degrees C with desiccant lost 10% activity in three days. At the end of 30days, specimens stored under 'Extreme'-humidity >50% without desiccant- conditions at 37 degrees C assayed below the NSQAP cut off for G6PD. Humidity exacerbated loss of enzyme activity with increasing temperature and time duration. CONCLUSION: Data suggest that G6PD PT materials can be stored at 4 degrees C and used for up to one month and can be stored at -20 degrees C for one year and yield >90% enzyme activity. Exposure to warm temperatures, especially with elevated humidity, should be avoided. Desiccant should always be used to mitigate humidity effects. |
Influence of Hematocrit and Total-Spot Volume on Performance Characteristics of Dried Blood Spots for Newborn Screening
Hall EM , Flores SR , De Jesús VR . Int J Neonatal Screen 2015 1 (2) 69-78 Dried blood spots (DBS) have been used in newborn screening (NBS) tests for over 50 years. The Newborn Screening Quality Assurance Program (NSQAP) at the Centers for Disease Control and Prevention (CDC) conducted studies to assess the individual impacts of hematocrit and total-spot volume on characteristics of DBS samples. Per-punch serum volumes decreased 27%, RBC volumes more than doubled, absorption times increased over 300%, and spot diameters decreased marginally between the hematocrits of 40% to 65%. Per-punch serum and RBC volumes decreased logarithmically with lowering total-spot volumes. Patient hematocrit is an uncontrollable variable and inevitably affects the resulting punch from a DBS sample. It may be possible, though, to identify samples that fall outside of an acceptable range by noting certain physical characteristics of the DBS. |
Active tracing and monitoring of contacts associated with the first cluster of Ebola in the United States
Chung WM , Smith JC , Weil LM , Hughes SM , Joyner SN , Hall EM , Ritch J , Srinath D , Goodman E , Chevalier MS , Epstein L , Hunter JC , Kallen AJ , Karwowski MP , Kuhar DT , Smith C , Petersen LR , Mahon BE , Lakey DL , Schrag SJ . Ann Intern Med 2015 163 (3) 164-73 BACKGROUND: Following hospitalization of the first patient with Ebola virus disease diagnosed in the United States on 28 September 2014, contact tracing methods for Ebola were implemented. OBJECTIVE: To identify, risk-stratify, and monitor contacts of patients with Ebola. DESIGN: Descriptive investigation. SETTING: Dallas County, Texas, September to November 2014. PARTICIPANTS: Contacts of symptomatic patients with Ebola. MEASUREMENTS: Contact identification, exposure risk classification, symptom development, and Ebola. RESULTS: The investigation identified 179 contacts, 139 of whom were contacts of the index patient. Of 112 health care personnel (HCP) contacts of the index case, 22 (20%) had known unprotected exposures and 37 (30%) did not have known unprotected exposures but interacted with a patient or contaminated environment on multiple days. Transmission was confirmed in 2 HCP who had substantial interaction with the patient while wearing personal protective equipment. These HCP had 40 additional contacts. Of 20 community contacts of the index patient or the 2 HCP, 4 had high-risk exposures. Movement restrictions were extended to all 179 contacts; 7 contacts were quarantined. Seven percent (14 of 179) of contacts (1 community contact and 13 health care contacts) were evaluated for Ebola during the monitoring period. LIMITATION: Data cannot be used to infer whether in-person direct active monitoring is superior to active monitoring alone for early detection of symptomatic contacts. CONCLUSION: Contact tracing and monitoring approaches for Ebola were adapted to account for the evolving understanding of risks for unrecognized HCP transmission. HCP contacts in the United States without known unprotected exposures should be considered as having a low (but not zero) risk for Ebola and should be actively monitored for symptoms. Core challenges of contact tracing for high-consequence communicable diseases included rapid comprehensive contact identification, large-scale direct active monitoring of contacts, large-scale application of movement restrictions, and necessity of humanitarian support services to meet nonclinical needs of contacts. PRIMARY FUNDING SOURCE: None. |
Performance of succinylacetone assays and their associated proficiency testing outcomes
Adam BW , Hall EM , Meredith NK , Lim TH , Haynes CA , De Jesus VR , Hannon WH . Clin Biochem 2012 45 (18) 1658-63 BACKGROUND: Succinylacetone (SUAC) is the primary metabolic marker for hepatorenal tyrosinemia. MATERIALS AND METHODS: We used results reported for dried-blood-spot proficiency testing (PT) specimens and hepatorenal tyrosinemia patients' newborn screening (NBS) samples to demonstrate analytic biases in SUAC recoveries and differences in presumptive clinical classifications. RESULTS: SUAC recoveries from non-kit and NeoBase kit tandem mass spectrometry methods were markedly different. Kit users that set high cutoff values submitted discordant clinical assessments of "within normal limits" for PT specimens enriched with 10-15mcmol SUAC/L in blood. SUAC levels in tyrosinemia patients' NBS samples analyzed by NeoBase kit were lower than those in samples analyzed by non-kit methods. CONCLUSIONS: From 2009 to 2011, analytic biases in SUAC recoveries were consistent. Discordant clinical assessments of PT specimens were associated with high cutoff values for NeoBase kit results. Method-related differences in SUAC concentrations of tyrosinemia patients' samples were consistent with those of PT specimens. |
The stability of markers in dried-blood spots for recommended newborn screening disorders in the United States
Adam BW , Hall EM , Sternberg M , Lim TH , Flores SR , O'Brien S , Simms D , Li LX , De Jesus VR , Hannon WH . Clin Biochem 2011 44 1445-50 OBJECTIVE: We aimed to measure separately the contributions of heat and humidity to changes in levels of 34 markers of inborn disorders in dried-blood-spot (DBS) samples. DESIGN AND METHODS: We stored paired sets of DBSs at 37 degrees C for predetermined intervals in low-humidity and high-humidity environments. Marker levels of all samples in each complete sample set were measured in a single analytic run. RESULTS: During the 30+/-5day studies, galactose-1-phosphate uridyltransferase and biotinidase lost almost 65% of initial activities in low-humidity storage; most of the degradation in 27 other markers was attributable to adverse effects of high-humidity storage; seven markers in DBSs stored at high humidity lost more than 90% of initial levels by the end of the study and 4 of the 7 lost more than 50% of initial levels within the first week of storage. CONCLUSIONS: Minimizing both humidity and temperature in DBS transportation and storage environments is essential to maintaining sample integrity. |
The preparation and storage of dried-blood spot quality control materials for lysosomal storage disease screening tests
Adam BW , Orsini JJ Jr , Martin M , Hall EM , Zobel SD , Caggana M , Hannon WH . Clin Biochem 2011 44 704-10 OBJECTIVE: We aimed to prepare dried-blood spot (DBS) quality control (QC) materials for lysosomal storage disease (LSD) screening tests and to determine optimum blood and DBS storage conditions. METHODS: We compared enzyme activities of five LSD markers in adult blood, umbilical-cord blood, and leukocyte-reduced blood. We measured activities in liquid blood and DBSs after predetermined intervals at controlled temperatures and humidities. RESULTS: Lysosomal-enzyme activity levels in umbilical-cord blood mimicked those in newborn screening samples. Lysosomal-enzyme activities in leukocyte-reduced blood were lower than in LSD-positive patient samples. Enzyme activities were stable in refrigerated liquid blood for 32days and in frozen DBSs stored at low humidity for a year. Activity losses from DBSs after 34days at 37+/-1 degrees C were 35-66% in low humidity and 61-100% in high humidity. CONCLUSIONS: Umbilical-cord blood is the preferred matrix for LSD-normal DBS QC materials. Leukocyte-reduced blood is lysosomal enzyme-deficient. Failure to control humidity during DBS storage results in loss of lysosomal-enzyme activities. |
Preliminary proficiency testing results for succinylacetone in dried blood spots for newborn screening for tyrosinemia type I
Adam BW , Lim TH , Hall EM , Hannon WH . Clin Chem 2009 55 (12) 2207-13 BACKGROUND: Succinylacetone (SUAC) is the primary metabolite accumulated in tyrosinemia type I-an inborn error of metabolism that, if untreated, can cause death from liver failure during the first months of life. Newborn screening laboratories measure SUAC in dried blood spot (DBS) samples to detect asymptomatic tyrosinemia type I. We used panels of SUAC-enriched DBSs to compare and evaluate the performance of these screening tests. METHODS: We prepared sets of DBS materials enriched with predetermined SUAC concentrations and distributed samples of these materials, along with a screening practices questionnaire, to laboratories that perform SUAC tests. We compared their reported SUAC concentrations and questionnaire responses to identify screening practices that affect SUAC test outcomes. RESULTS: Data from 2 pilot surveys showed large differences among laboratories in SUAC recoveries, reproducible within-laboratory recoveries, and stable performance of the DBS materials. Results from 257 proficiency test analyses contained a total of 6 false-negative misclassifications. Reported recoveries of added SUAC ranged from 0 to >200%. Low-biased SUAC recoveries were associated with 1 method used by 5 laboratories. All laboratories that reported SUAC recoveries ≥100% used DBS matrix calibrators. CONCLUSIONS: The wide ranges of SUAC concentrations reported for pilot and proficiency testing specimens demonstrate a need to harmonize quantitative results among laboratories. Although DBS matrix calibrators are important for optimizing SUAC recoveries, the preparation of these calibrators is not standardized among laboratories. Certified DBS-based SUAC calibrators are needed for accuracy and harmonization. |
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