CYP2D6 inhibition by diphenhydramine leading to fatal hydrocodone overdose.

OBJECTIVES: Fatal drug overdoses often involve multiple co-intoxicants, including opioids. Hydrocodone, the most prescribed opioid for pain management, is metabolized to the active metabolite hydromorphone by hepatic CYP2D6. Inhibition of CYP2D6 by other compounds can disrupt the analgesic properties of hydrocodone and extend its half-life. Diphenhydramine is an over-the-counter cold medication and is known to inhibit CYP2D6 activity. CASE PRESENTATION: A woman in her late 50s was prescribed hydrocodone/acetaminophen (Norco® 10/325). Days before her death, she began taking diphenhydramine for cold symptoms. A post-mortem toxicology report detected the following compounds by High Performance Liquid Chromatography/Time of Flight-Mass Spectrometry (LC/TOF-MS) analysis: acetaminophen (14 µg/mL), hydrocodone (410 ng/mL), dihydrocodeine (24 ng/mL), and diphenhydramine (150 ng/mL). Hydromorphone was not detected (<2 ng/mL). All compounds were detected in therapeutic concentrations, except for hydrocodone, which was present at lethal concentrations. CONCLUSIONS: This case highlights a fatal drug-drug interaction between hydrocodone and diphenhydramine. The estimated total body burden of hydrocodone was 6- to 12-fold higher than acetaminophen, which is unexpected, as these two drugs were administered as a single formulation and have similar half-lives. Furthermore, hydromorphone was undetectable. Taken together, these findings are highly suggestive of a fatal opioid overdose precipitated by diphenhydramine.

Endogenous and iatrogenic sources of variability in response to opioid therapy in Post-Surgical and injured orthopedic patients.

BACKGROUND: Hydrocodone is the most prescribed opioid in the US. The objective was to evaluate associations between genetic, intrinsic, and extrinsic patient factors, plasma hydrocodone and metabolites, common side effects, and pain scores in a cohort of orthopedic surgery patients. METHODS: Data for each patient was collected by review of the electronic hospital record (EHR), and patient interview. Patients were recruited from those with trauma or undergoing scheduled elective surgery for total knee replacement or total hip at the University of Louisville Hospital, Baptist East Hospital, and Jewish Hospital, Louisville, KY. Plasma opiate concentrations and a targeted genotyping panel was performed. RESULTS: There were statistically significant correlations with daily (p < 0.001) and total dose (p = 0.002) of hydrocodone in hospital and duration of opioid therapy. The length of opioid administration was significantly shorter in CYP2D6 EM/UM versus CYP2D6 PM/IM patients (p = 0.018). Subjects with the OPRM1 c.118G variant were also on opioids longer (p = 0.022). The effect of co-administration of a CYP2D6 inhibitor had a significant effect on the length of opioid therapy (P < 0.001). And not surprisingly the effect of the inhibitor adjusted CYP2D6 phenotype was greater in both the hospital stay period and days of opioid use post hospital discharge (p < 0.001). CONCLUSIONS: Based on this study, patients should be evaluated for the use of inhibitors of CYP2D6, during hydrocodone therapy can alter the phenotype of the patient (phenocopy) and increase the probability that the patient will be on opioids for longer periods of time.

A Shared Diagnostic Stewardship Approach toward Improving Autoimmune Encephalopathy Send-out Testing Utilization.

BACKGROUND: For many laboratories, autoimmune encephalopathy (AE) panels are send-out tests. These tests are expensive, and ordering patterns vary greatly. There is also a lack of consensus on which panel to order and poor understanding of the clinical utility of these panels. These challenges were presented to our newly formed, multidisciplinary, diagnostic stewardship committee (DSC). Through this collaboration, we developed an algorithm for ordering AE panels; combining diagnostic criteria with practice guidelines. METHODS: We analyzed test-ordering patterns in 2018 and calculated a true-positive rate based on clinical presentation and panel interpretation. An evidence-based approach was combined with input from the Department of Neurology to synthesize our algorithm. Efficacy of the algorithm (number of panels ordered, cost, and true positives) was assessed before and after implementation. RESULTS: In 2018, 77 AE-related panels were ordered, costing $137 510. The true-positive rate was 10%, although ordering multiple, similar panels for the same patient was common. Before implementing the algorithm (January 1-July 31, 2019), 55 panels were ordered, costing $105 120. The total true-positive rate was 3.6%. After implementation, 23 tests were ordered in a 5-month period, totaling $50 220. The true-positive rate was 13%. CONCLUSION: With the DSC-directed mandate, we developed an algorithm for ordering AE panels. Comparison of pre- and postimplementation data showed a higher true-positive rate, indicating that our algorithm was able to successfully identify the at-risk population for AE disorders. This was met with a 43% decrease in the number of tests ordered, with total cost savings of $25 000 over 5 months.

ELISA-based detection of Open Reading Frame protein 1 in patients at risk of developing lung cancer.

BACKGROUND: Early detection of lung cancer significantly improves survival outcomes. Thus, lung cancer screening for high-risk individuals using low-dose CT scan (LDCT) is recommended. LDCT has several limitations, and often requires invasive follow up. Previously, we have developed an ELISA for measurement of Open Reading Frame 1 protein (ORF1p) in serum. We assessed whether ORF1p can be used as a risk assessment biomarker for patients at high risk for developing lung cancer. PATIENTS: Patients with risk factors for lung cancer were enrolled in our study with consent under IRB approval. A total of 122 patients were included. The lung cancer cohort consisted of 38 patients with varying stages of cancer undergoing treatment. METHODS: ORF1p quantification was performed using our ELISA assay on serum samples. RESULTS: ORF1p was significantly increased in the serum of patients with identified lung nodules compared to those without nodules (P = 0.0007). ORF1p was also significantly increased in patients who were recommended for follow up (P = 0.0004). When comparing the at-risk cohort to patients with lung cancer, there was not a significant difference in ORF1p levels. CONCLUSION: ORF1p can be used to identify patients at high risk of developing lung cancer and may provide an effective, non-invasive risk assessment marker to complement LDCT screening.

Does an antibiotic nail made in a lubricated tube release antibiotic?

INTRODUCTION: The treatment of long-bone osteomyelitis has long been a difficult problem. Recently, antibiotic-impregnated intramedullary rods for the treatment of infected long-bone fractures have been gaining popularity but they are quite difficult to fabricate. Recently, a new technique that utilizes mineral oil to coat the inside of a chest tube mold prior to introduction of cement has been proven to ease fabrication. We hypothesized that the use of mineral oil would alter the elution characteristics of tobramycin from the intramedullary device. METHODS: Two groups of antibiotic nails were fabricated under sterile conditions. The control group utilized a chest tube mold. The study group utilized a chest tube that was coated with mineral oil prior to cement injection. Each intramedullary nail was placed in pooled human serum and incubated under physiologic conditions. The level of tobramycin in each sample was measured at timepoints 0, 1, 6, and 24 h. RESULTS: There was no significant difference when comparing control with the experimental group at any timepoint. Antibiotic nails eluted tobramycin at a rapid rate in the first 6 h of exposure to serum, regardless of their preparation with oil or without oil. The rate of elution fell precipitously between 6 and 24 h. CONCLUSION: We believe that although this study, as with any study, cannot perfectly recreate in vivo conditions, we have clearly shown that mineral oil has no significant effect on elution of tobramycin from antibiotic nails.

Verification of Newly FDA-Approved Kappa and Lambda Free Light Chain Assays on a Previously Untested Platform.

BACKGROUND: κ and λ free light chains (FLCs) are monitored to aid in the diagnosis of plasma cell disorders. Our goal was to validate the Diazyme Human κ and λ assays on Beckman Coulter UniCel DxC 800 Synchron and compare to Freelite κ and λ assays on Roche Cobas Integra. METHODS: Linearity verification, within- and between-run precision, method comparison, and reference range (RR) verification were conducted using CLSI guidelines. Statistical analysis was performed using EP Evaluator®. Mean, SD, CV, and bias were determined. RESULTS: Diazyme κ FLC assay was linear within 0.00-191.00 mg/L. Diazyme λ FLC assay was linear within 0.00-205.30 mg/L. Diazyme κ FLC QC1 had a mean of 16.70 mg/L, CV of 7.0%. QC2 had a mean of 33.37 mg/L, CV of 2.6%. Diazyme λ FLC QC1 had a mean of 21.73 mg/L, CV of 2.3%. QC2 had a mean of 42.05 mg/L, CV of 1.5%. Bias of DxC-Diazyme FLCs compared to Integra-Freelite FLCs was -2.55 mg/L (κ FLC), and 4.54 mg/L (λ FLC). Qualitative comparison of κ FLC assays indicated 100% agreement for both normal and abnormal values. For λ FLC assay, agreement was 95% for normal values and 75% for abnormal values. For κ/λ ratio there was 50% agreement for normal values, and 100% for abnormal values. For RR verification, 1 sample was outside the Diazyme κ RR. For λ, all samples were within the manufacturer's RR. CONCLUSIONS: Diazyme assays for FLCs have excellent precision and accuracy and are comparable to Freelite assays.

Lack of Influence by CYP3A4 and CYP3A5 Genotypes on Pain Relief by Hydrocodone in Postoperative Cesarean Section Pain Management.

BACKGROUND: Genetic polymorphisms of cytochrome P450 are contributors to variability in individual response to drugs. Within the P450 family, CYP2D6 is responsible for metabolizing hydrocodone, a widely prescribed opioid for pain management. Alternatively, CYP3A4 and CYP3A5 can form norhydrocodone and dihydrocodeine. We have previously found that in a postcesarean section cohort, the rate of hydromorphone formation was dependent on the genotype of CYP2D6 and that plasma hydromorphone, not hydrocodone, was predictive of pain relief. METHOD: Blood was obtained from a postcesarean cohort that were surveyed for pain response and common side effects. Plasma samples were genotyped for CYP3A4/5, and their hydrocodone concentrations were measured by LC-MS. R statistical software was used to check for differences in the outcomes due to CYP3A4/5 and CYP2D6, and a multivariate regression model was fit to determine factors associated with pain score. RESULTS: Two-way ANOVA between CYP3A4/A5 and CYP2D6 phenotypes revealed that the former variants did not have a statistical significance on the outcomes, and only CYP2D6 phenotypes had a significant effect on total dosage (P = 0.041). Furthermore, a 3-way ANOVA analysis showed that CYP2D6 (P = 0.036) had a predictive effect on plasma hydromorphone concentrations, and CYP3A4/A5 did not have any effect on the measured outcomes. CONCLUSIONS: With respect to total dosages in a cesarean section population, these results confirm that CYP2D6 phenotypes are predictors for plasma hydromorphone concentration and pain relief, but CYP3A4/A5 phenotypes have no influence on pain relief or on side effects.

Long interspersed nuclear element-1 mobilization as a target in cancer diagnostics, prognostics and therapeutics.

Long Interspersed Nuclear Element-1 (LINE-1) are DNAs that compromise 17% of our genome. LINE-1 expression is triggered by environmental stressors and accomplished through its demethylation leading to genomic instability. Expression of LINE-1 is regulated in adult somatic tissues through several endogenous defensive mechanisms, but is found to be associated with tumorigenesis in several cancers. This finding, has inspired the use of different indicators of LINE-1 activation, as biomarkers in cancer diagnostics and even therapeutic targets in recent years. The objective of this review is to provide a critical examination of LINE-1 elements as companion cancer diagnostic/prognostic biomarkers and anti-cancer drug targets. In our view, there's great potential for LINE-1 serving at both forefronts, but there is a need for more mechanistic studies in the clinic as well as on the bench research to validate LINE-1 activation elements as cancer biomarkers or therapeutic targets; in different cancer types and/or stages of the disease. In this context, development of minimally invasive, reliable and sensitive diagnostic tools for LINE-1 activation elements for clinical use, is of priority.

Discovery of the Long Interspersed Nuclear Element-1 activation product [Open Reading Frame-1 (ORF1) protein] in human blood.

Long Interspersed Nuclear Element 1 is the only autonomous mobile DNA capable of self-propagation, and is an environmental biomarker that is activated upon an environmental trigger. We have developed an ELISA method to detect and measure Open Reading Frame-1 (ORF1) and have applied it to interrogate serum samples from men with equivocal prostate specific antigen (PSA) results. Polyclonal antibodies were developed using the first 14-amino acid peptide of N-terminal-ORF1 protein. Remnant serum samples from a total of 53 men, ages>50 yr, were analyzed for immunoreactive ORF1 (iORF1) and PSA concentrations; outcomes for the non-biopsied and biopsied groups were also recorded. The dynamic range of the ELISA was between (CV): 2.0 (14%) to 30 ng/mL (1.2%). The total imprecision (within-run/inter-day) was: QC3 = 2.7%/21%, QC6 = 1.1%/18%, and QC20 = 0.33%/11%. The median iORF1 concentration in the non-biopsy group was 14.7 ng/mL (Q1 - Q3: 10.5 - Q3:18.4), which was significantly lower than the Biopsy group at 25.0 ng/mL (Q1 - Q3: 20.0-33.1), P-value = .003. In conclusion, we have developed a competitive ELISA and discovered the presence of iORF1 in serum, which could be used to advance future studies involving ORF1 measurement from blood. In addition, iORF1 may be a complement with the PSA screen to better detect prostate cancer.

Analytical interference of HBOC-201 (Hemopure, a synthetic hemoglobin-based oxygen carrier) on four common clinical chemistry platforms.

BACKGROUND: There are 13 million blood transfusions each year in the US. Limitations in the donor pool, storage capabilities, mass casualties, access in remote locations and reactivity of donors all limit the availability of transfusable blood products to patients. HBOC-201 (Hemopure®) is a second-generation glutaraldehyde-polymer of bovine hemoglobin, which can serve as an "oxygen bridge" to maintain oxygen carrying capacity while transfusion products are unavailable. Hemopure presents the advantages of extended shelf life, ambient storage, and limited reactive potential, but its extracellular location can also cause significant interference in modern laboratory analyzers similar to severe hemolysis. METHODS: Observed error in 26 commonly measured analytes was determined on 4 different analytical platforms in plasma from a patient therapeutically transfused Hemopure as well as donor blood spiked with Hemopure at a level equivalent to the therapeutic loading dose (10% v/v). RESULTS: Significant negative error ratios >50% of the total allowable error (>0.5tAE) were reported in 23/104 assays (22.1%), positive bias of >0.5tAE in 26/104 assays (25.0%), and acceptable bias between -0.5tAE and 0.5tAE error ratio was reported in 44/104 (42.3%). Analysis failed in the presence of Hemopure in 11/104 (10.6%). Observed error is further subdivided by platform, wavelength, dilution and reaction method. CONCLUSION: Administration of Hemopure (or other hemoglobin-based oxygen carriers) presents a challenge to laboratorians tasked with analyzing patient specimens. We provide laboratorians with a reference to evaluate patient samples, select optimal analytical platforms for specific analytes, and predict possible bias beyond the 4 analytical platforms included in this study.

Multicenter evaluation of analytical characteristics of the Elecsys® Periostin immunoassay.

OBJECTIVE: The multifunctional cytokine IL-13 is thought to play a central role in Type 2 inflammation in asthma. Serum periostin has been explored as a candidate biomarker for evaluating IL-13 activity in the airway. We describe the technical performance characteristics of a novel, fully automated immunoassay for the determination of periostin in serum. DESIGN AND METHODS: Limit of blank [LoB], limit of detection [LoD] and limit of quantitation [LoQ], linearity, precision and reproducibility across sites and lots were evaluated according to Clinical and Laboratory Standards Institute guidelines. Interferences and sample stability were also investigated. RESULTS: The pre-specified values for LoB (2ng/mL), LoD (4ng/mL) and LoQ (10ng/mL) were met. The assay was linear throughout the measuring range (10-160ng/mL) with recoveries within ±10% of target at concentrations >30ng/mL and within ±3ng/mL at concentrations ≤30ng/mL. Recovered periostin concentrations were also within ±10% of target in presence of 43 potentially interfering substances and drugs. Samples were stable across various storage conditions and durations (24h at room temperature, 7days at 4°C, 12weeks at -20°C, and 3 freeze/thaw cycles). Repeatability experiments resulted in CVs across samples and controls ranging from 0.9-1.5%. Intermediate precision was 1.2-1.7% and reproducibility including 3 testing sites and 3 reagent lots was 1.7-3.1%. The final assay correlates to the assay version used in previous clinical trials (Pearson's r=0.998, bias at 50ng/mL=1.2%). CONCLUSION: The performance evaluation of the Elecsys® Periostin immunoassay including a multicenter precision analysis demonstrated that the assay is suitable for measuring serum periostin at clinically important concentrations around 50ng/mL.

Reference intervals of urinary acute kidney injury (AKI) markers [IGFBP7]∙[TIMP2] in apparently healthy subjects and chronic comorbid subjects without AKI.

BACKGROUND: Insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) have demonstrated significantly improved diagnostic performance in assessing risk for acute kidney injury (AKI) compared with existing biomarkers. We present the findings of a multi-site trial to determine the reference intervals for these biomarkers in apparently healthy adults and those with stable chronic morbid conditions without AKI. METHODS: A urine specimen was collected from apparently healthy subjects (N=378) and subjects with at least one stable chronic morbidity (N=372). Specimens were kept frozen until analysis with the NephroCheck® Test (Astute Medical). The test is comprised of fluorescence immunoassays for IGFBP7 and TIMP-2 and is used with the Astute140® Meter which quantifies the concentration of each biomarker. The meter multiplies the concentrations of IGFBP7 and TIMP-2 and displays the result as a numerical value ([IGFBP7]∙[TIMP-2]) expressed in (ng/ml)(2)/1000 which is called the AKIRisk™ Score. RESULTS: The reference intervals (inner 95%) for [IGFBP7]∙[TIMP-2] in all subjects (N=750), apparently healthy subjects, and subjects with stable chronic morbidities were 0.04-2.22, 0.04-2.25, and 0.05-2.20 (ng/ml)(2)/1000 respectively. There was no statistical difference between reference intervals for apparently healthy and chronic stable morbid cohorts (p=0.42). CONCLUSIONS: Our investigation showed that urine [IGFBP7]∙[TIMP-2] values were not elevated in patients with stable chronic morbidities who did not have AKI.

Demographic data for urinary Acute Kidney Injury (AKI) marker [IGFBP7]·[TIMP2] reference range determinations.

This data in brief describes characteristics of chronic stable comorbid patients who were included in reference range studies of [IGFBP7]·[TIMP-2] "Reference Intervals of Urinary Acute Kidney Injury (AKI) Markers [IGFBP7]·[TIMP2] in Apparently Healthy Subjects and Chronic Comorbid Subjects without AKI" [1]. In order to determine the specificity of [IGFBP7]·[TIMP-2] for identifying patients at risk of developing AKI we studied a cohort with nine broad classification of disease who did not have AKI. Details regarding the population that was targeted for inclusion in the study are also described. Finally, we present data on the inclusion criteria for the healthy subjects used in this investigation to determine the reference range.

A clinical approach to solving discrepancies in therapeutic drug monitoring results for patients on sirolimus or tacrolimus: Towards personalized medicine, immunosuppression and pharmacogenomics.

BACKGROUND: Unexpected clinical laboratory concentrations often need to be investigated before they are acted upon in a clinical setting. Therapeutic drug monitoring (TDM) frequently involves drugs with narrow therapeutic windows and can be harmful to the patient if changes are made based on erroneous serum drug concentrations. Too little of the drug will result in ineffective therapy and too much of the drug can cause life threatening toxicities. There are many factors that can result in unexpected serum drug concentrations including differences in analytical methods being used, diet, timing of blood draw, genotype and compliance. All these factors should all be considered before deciding if changes should be made in a patient's therapeutic course. CASE REPORT: We determined the cause of 2 patient's unexpected TDM concentrations for sirolimus and tacrolimus. Using this approach in 2 patient cases, we describe how co-treatment and uncommon genotypes result in unexpected drug concentrations. CONCLUSIONS: Both cases involved unexpected drug values. In the first case, the cause was revealed to be a drug that was added to the patient's treatment regimen (posaconazole) that inhibits CYP3A4 which is responsible for sirolimus metabolism. In the second case, the patient was revealed to have an uncommon genotype for CYP3A5, causing higher metabolism and lower serum tacrolimus concentrations than the general population.

Pesticide-induced quadriplegia in a 55-year-old woman.

Acephate is a commercial organophosphate pesticide formerly used in households and now used primarily for agriculture. Poisoning symptoms include salivation, lacrimation, urination, defecation, gastrointestinal illness, and emesis. In addition to these classic symptoms, neurodegeneration can result from increased and continued exposure of organophosphates. This 55-year-old woman presented with organophosphate-induced delayed neuropathy in the form of quadriplegia due to the commonly used pesticide acephate. She was exposed to this pesticide through multiple sprayings in her work office with underrecognized poisoning symptoms. She presented to her primary care physician with neuropathic pain and paralysis in her arm following the sprayings and eventual complete paralysis. The patient lived for 2 years following her toxic exposure and quadriplegia. A complete autopsy after her death confirmed a transverse myelitis in her spinal cord. We conclude that in susceptible individuals, acephate in excessive amounts can produce severe delayed neurotoxicity as demonstrated in animal studies.

Resolving a case of concurrent hepatitis B virus surface antigen (HBsAg) and surface antibody (HBsAb).

BACKGROUND: In most cases, patients appear to recover from acute hepatitis B virus (HBV) infection and do not exhibit the surface antigen (HBsAg). Chronic carriers are positive for HBsAg but HBsAb is usually not present. After acute infection only HBsAb remains. The presence of both HBsAg and HBsAb is unusual. METHODS: We report on a patient whose results were analytically and clinically discrepant--positive for HBsAg and HBsAb on one testing platform but only HBsAg on another platform. RESULTS: Reasons for this result: 1) Interference from endogenous antibodies; 2) HBsAg is from one strain and HBsAb is from another: and 3) The presence of HBsAb and HBsAg. Growing evidence indicates that both may be present in many patients. Low HBsAb may be neutralized and not recognized by the solid-phase HBsAg in the assay. Likewise, low HBsAg may be neutralized by HBsAb. It remains unclear whether HBsAg is always cleared after acute infection. CONCLUSIONS: Testing indicated that both HBsAb and HBsAb were present. The data shows that different testing platforms may produce different results depending on the kinetics, the exposure of the capture HBsAg and the extent of endogenous HBAg/HBsAb. We demonstrate a simple way to rule out test interference to presumptively identify true HBsAb.

Hydrocodone in postoperative personalized pain management: pro-drug or drug?

BACKGROUND: Genetic variations in enzymes that produce active metabolites from pro-drugs are well known. Such variability could account for some of the clinically observed differences in analgesia and side effects seen in postoperative patients. Using genotyping and quantitation of serum concentrations of hydrocodone and its metabolites, we sought to demonstrate the clinical effects of the metabolites of hydrocodone on pain relief. The objective of the current study was to determine whether CYP2D6 genotype and serum hydromorphone levels account for some of the variability in pain relief seen with hydrocodone in a cohort of women post-Cesarean section. METHODS: In 156 post-Cesarean section patients who received hydrocodone, we assessed serum opioid concentrations and CYP2D6 genotypes. Blood samples were collected at that time for genotyping and determination of concentrations of hydrocodone and metabolites by LC-MS/MS. Multivariate analysis was used to determine the relationship between CYP2D6 genotypes, pain relief, side effects, and serum concentrations of hydrocodone and hydromorphone. RESULTS: The CYP2D6 genotyping results indicated that 60% of subjects were extensive, 30% intermediate, 3% poor, and 7% ultra-rapid metabolizers. In the poor metabolizers, the mean plasma hydromorphone concentration was 8-fold lower when compared to that of ultra-rapid metabolizers. Hydromorphone, and not hydrocodone concentrations correlated with pain relief. CONCLUSIONS: This study shows that hydromorphone is generated at substantially different rates, dependent on CYP2D6 genotype. Pain relief correlated with plasma concentrations of hydromorphone, and not with hydrocodone. This suggests that pain relief will vary with CYP2D6 genotype. Inability to metabolize hydrocodone to hydromorphone as seen in the poor metabolizers should alert the clinician to consider alternative medications for managing pain postoperatively.

Testing of gastric contents for peanut proteins in a 13-year old anaphylaxis victim.

BACKGROUND: We report the case of a 13-y female who went into anaphylactic shock following the ingestion of a meal suspected to be contaminated by peanuts. The teenager had a known sensitivity to peanuts, however, the restaurant claimed that no peanut products were used in the preparation of her meal. The gastric contents of the decedent were retained and tested for peanut proteins due to the possible legal liability of the proprietor. METHOD: Using antibodies against peanut proteins (roasted and unroasted), we optimized a method to detect total soluble peanut proteins by Western-blot analysis in gastric contents. In addition, we validated two commercially available tests which were originally intended for detection of peanut proteins in food matrices to examine the same gastric sample. One was an enzyme-linked immunosorbent assay (ELISA) that utilized polyclonal antibodies against Ara h 1 (Tepnel Life Sciences). The other was a laminar-flow assay directed against Ara h 1, Ara h 2 and Ara h 3 (R-Biopharm). A positive food-based control was created by reducing bread and peanuts (1:1, w/w) with water (1:1, w/v) using a mortar and pestle. A food-based negative food control was created similar to the positive control, except the peanuts were omitted and the amount of bread was doubled. RESULTS: The Western-blot assay was sensitive down to 2.5ng/ml of total peanut protein. The laminar flow was the most rapid and least complex. The ELISA was the most analytically sensitive with a cut-off of 1ng/ml of Ara h 1 protein compared to the laminar flow which had a cut-off of 4ng/ml Ara h 1 equivalent. Both ELISA and laminar flow assays were able to detect peanut proteins in the food matrices and positive controls, and not in negative controls. No peanut related proteins were detected in the decedent's gastric sample. The gastric sample spiked with peanuts was reliably detectable. CONCLUSION: The anaphylaxis patient had no peanut allergens detected in her gastric contents by any of the three methods employed. Both commercially available assays are easily adaptable for testing peanut allergens in the gastric contents as judged by the results of the immunoassays as well as the Western blot analysis. Due to the rising need for detecting peanut proteins in various heterogeneous and complex matrices, the use of appropriate controls should be also considered in these unique investigations.

Undetected hypoglycemia in a patient receiving TPN.

CASE REPORT: A 58-year-old female was admitted to the hospital in a severely malnourished state. She was treated for Crohn's disease with total parental nutrition (TPN). The patient's blood glucose was monitored by point of care (POC) testing every 4h, and a specimen is also drawn daily for metabolic assessment. The POC blood glucose values were consistently much higher than the lab values. Humalog insulin (5 U) was given to the patient to decrease high blood glucose levels that developed following administration of TPN. The patient then became hypoglycemic as a result of this insulin treatment. POC glucose testing, performed every 4h, did not detect the iatrogenic hypoglycemia, while lab glucose results were not given close attention. The lab sample was always drawn 1-2h after insulin was given to the patient and resulted in a lower blood glucose value. In addition, the symptoms of hypoglycemia such as shaking and dizziness were masked by the patient's poor health status, supine position, and the continuously given TPN. CONCLUSIONS: These findings highlighted the importance of the correct sampling time following insulin administration and the consideration of the lab results in addition to POC. The patient's insulin regimen was modified to prevent further hypoglycemic events.

The role of hydromorphone and OPRM1 in postoperative pain relief with hydrocodone.

BACKGROUND: Postoperative pain management remains a challenge for clinicians due to unpredictable patient responses to opioid therapy. Some of this variability may result from single nucleotide polymorphisms (SNPs) of the human opioid mu-1 receptor (OPRM1) that modify receptor binding or signal transduction. The OPRM1 variant with the highest frequency is the A118G SNP. However, previous studies have produced inconsistent results regarding the clinical effects of A118G on opioid response. We hypothesized that measurement of serum opioid concentrations, in addition to determining total opioid consumption, may provide a more precise method of assessing the effects of A118G on analgesic response. The current study evaluated the relationship of analgesia, side effects, total hydrocodone consumption, quantitative serum hydrocodone and hydromorphone concentrations, and A118G SNP in postoperative patients following Cesarean section. METHODS: 158 women scheduled for Cesarean section were enrolled prospectively in the study. The patients had bupivacaine spinal anesthesia for surgery and received intrathcal morphine with the spinal anesthetic or parenteral morphine for the first 24 hours after surgery. Thereafter, patients received hydrocodone/acetaminophen for postoperative pain control. On postoperative day 3, venous blood samples were obtained for OPRM1 A118G genotyping and serum opioid concentrations. RESULTS: 131 (82.9%) of the subjects were homozygous for the 118A allele of OPRM1 (AA) and 27 (17.1%) carried the G allele (AG/GG). By regression analysis, pain relief was significantly associated with total hydrocodone dose in the AA group (P = 0.01), but not in the AG/GG group (P = 0.554). In contrast, there was no association between pain relief and serum hydrocodone concentration in either group. However, pain relief was significantly associated with serum hydromorphone concentration (a metabolite of hydrocodone) in the AA group (P = 0.004), but not in the AG/GG group (P = 0.724). Conversely, side effects were significantly higher (P < 0.04) in the AG/GG group (mean = 6.4) than in the AA group (mean = 4.4), regardless of adjustment for BMI, pain level, or total dose of hydrocodone. CONCLUSION: This study found a correlation between pain relief and total hydrocodone dose in patients homozygous for the 118A allele (AA) of the OPRM1 gene, but not in patients with the 118G allele (AG/GG). However, pain relief in 118A patients did not correlate with serum hydrocodone concentrations, but rather with serum hydromorphone levels, the active metabolite of hydrocodone. This suggests that pain relief with hydrocodone may be due primarily to hydromorphone. Although pain relief did not correlate with opioid dose in AG/GG patients, they had a higher incidence of opioid side effects. The correlations identified in this study may reflect the fact that serum opioid concentrations were measured directly, avoiding the inherent imprecision associated with relying solely on total opioid consumption as a determinant of opioid effectiveness. Thus, measurement of serum opioid concentrations is recommended when assessing the role of OPRM1 variants in pain relief. This study supports pharmacogenetic analysis of OPRM1 in conjunction with serum opioid concentrations when evaluating patient responses to opioid therapy.