Pre-operative intravenous steroid improves pain and joint mobility after total knee arthroplasty in Chinese population: a double-blind randomized controlled trial.

INTRODUCTION: This study aims to investigate the effect of pre-operative intravenous methylprednisolone on post-operative pain control and joint mobility in Chinese patients undergoing single primary total knee arthroplasty. METHODS: This is a prospective, randomized, double-blinded, placebo-controlled single-centre trial. Sixty subjects were randomized into intervention and control group. The peri-operative anaesthetic and analgesic regimes were standardized. The intervention group received 125 mg methylprednisolone intravenously on the induction of anaesthesia. Subjects were assessed at 24, 30 and 48 h after surgery and upon discharge for pain scores and range of movement from the operated knee. Change in C-reactive protein level was calculated. Patient's satisfaction was recorded. Adverse reactions were documented. Subjects were followed up at 6 weeks, 4 months and 1 year. RESULTS: Rest pain and pain on movement were significantly reduced in the methylprednisolone group at 24 and 30 h after surgery (ANOVA p = 0.030, p = 0.003, p = 0.032, p = 0.010). The methylprednisolone group demonstrated a greater range of movement from the operated knee up to 30 h after surgery (ANOVA p = 0.031). Post-operative C-reactive protein level was significantly less in the methylprednisolone group (p < 0.001). Methylprednisolone group had a higher patient's satisfaction than the control group (p < 0.01). No adverse effects were noted at the 1-year follow-up. CONCLUSION: Pre-operative intravenous methylprednisolone improves post-operative pain and joint mobility after total knee arthroplasty up to 30 h after operation. It results in a higher patients' satisfaction. It can act as an effective adjunct in the multimodal analgesic regime. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03082092.

Recommendations for the Generation, Quantification, Storage, and Handling of Peptides Used for Mass Spectrometry-Based Assays.

BACKGROUND: For many years, basic and clinical researchers have taken advantage of the analytical sensitivity and specificity afforded by mass spectrometry in the measurement of proteins. Clinical laboratories are now beginning to deploy these work flows as well. For assays that use proteolysis to generate peptides for protein quantification and characterization, synthetic stable isotope-labeled internal standard peptides are of central importance. No general recommendations are currently available surrounding the use of peptides in protein mass spectrometric assays. CONTENT: The Clinical Proteomic Tumor Analysis Consortium of the National Cancer Institute has collaborated with clinical laboratorians, peptide manufacturers, metrologists, representatives of the pharmaceutical industry, and other professionals to develop a consensus set of recommendations for peptide procurement, characterization, storage, and handling, as well as approaches to the interpretation of the data generated by mass spectrometric protein assays. Additionally, the importance of carefully characterized reference materials-in particular, peptide standards for the improved concordance of amino acid analysis methods across the industry-is highlighted. The alignment of practices around the use of peptides and the transparency of sample preparation protocols should allow for the harmonization of peptide and protein quantification in research and clinical care.

Negative urine opioid screening caused by rifampin-mediated induction of oxycodone hepatic metabolism.

INTRODUCTION: Oxycodone has become widely used in the clinic for the treatment of chronic pain. This reflects its favorable pharmacokinetics and side effect profiles. CASE REPORT: We report a 60-y-old man who had a clinically significant drug interaction between rifampin and oxycodone, resulting in 3 consecutive negative urine oxycodone screens in a 2-month period, suggesting non-adherence. A combination of urine opioid metabolite quantification by GC/MS and CYP genotyping confirmed that he was compliant with his oxycodone therapy. Determination of the complete oxycodone metabolite profile and the CYP3A4/5 and 2D6 genotype allowed the physician to be confident that the patient was compliant with the medication (and not diverting it) and to increase his oxycodone dose to optimize his pain control. CONCLUSION: This case demonstrates how the combination of analytical toxicology and pharmacogenetic analyses enhances a physician's ability to personalize drug therapy in patients with chronic pain syndromes.

Pharmacogenomics as molecular autopsy for forensic toxicology: genotyping cytochrome P450 3A4*1B and 3A5*3 for 25 fentanyl cases.

Pharmacogenomics, the study on genetic contributions to drug action may help in certifying fentanyl toxicity. Fentanyl is used clinically as an adjunct to surgical anesthesia and for chronic pain management. Its toxicity may be partially due to cytochrome P450 (CYP) 3A4*1B and 3A5*3 variant alleles, resulting in variable fentanyl metabolism. In this study, we examined 25 fentanyl-related deaths (22 Caucasians, 1 African-American, and 2 Native-Americans) from the Milwaukee County Medical Examiner's Office and referral cases. Fentanyl and norfentanyl in postmortem blood samples were analyzed by radioimmunoassay and liquid chromatography-mass spectrometry-mass spectrometry. The samples were then genotyped for CYP3A4*1B and 3A5*3 using Pyrosequencing. Genotyping showed: 1 CYP3A4*1B homozygous and CYP3A5*3 heterozygous, 1 compound CYP3A4*1B and CYP3A5*3 heterozygous, 22 CYP3A4*1B wild type and CYP3A5*3 homozygous, and 1 CYP3A5*3 and CYP3A4*1B wild type. CYP variant allelic frequencies of the 25 cases were 6% for CYP3A4*1B and 92% for CYP3A5*3, compared with normal Caucasian CYP3A4*1B, 3-8%, and CYP3A5*3, 85-95%. The mean fentanyl concentration and metabolic ratio of fentanyl to norfentanyl of the 2 cases with CYP3A4*1B and CYP3A5*3 variants were 12.8 and 1.4 microg/L, respectively, lower than those of 22 cases with wild type CYP3A4*1B and CYP3A5*3 homozygous variants, 16.7 and 7.3 microg/L, respectively. The postmortem/in vivo data provided the first scientific evidence that CYP3A5 is involved in the fentanyl metabolism, and homozygous CYP3A5 *3 causes impaired metabolism of fentanyl, and genotyping CYP3A4*1B and 3A5*3 variants may help to certify the fentanyl toxicity.

Effects of citalopram on worry and brain activation in patients with generalized anxiety disorder.

The effects of auditory statements describing a personal worry on brain activation as measured by functional magnetic resonance imaging were examined in patients with generalized anxiety disorder (GAD) before and after anxiety reduction with citalopram. Six patients were imaged while listening to verbal descriptions of a personal worry or a neutral statement before treatment with citalopram and after 7 weeks of treatment. Pre-post drug analyses showed treatment with citalopram reduced self-reported anxiety and reduced BOLD responses to a pathology-specific worry and a neutral stimulus. After treatment, worry sentences, compared to neutral statements, elicit reduced BOLD responses in prefrontal regions, the striatum, insula and paralimbic regions. In addition, contrasts before and after treatment revealed reductions in the differential response that existed between worry and neutral statements. Overall reduction of BOLD response was most prominent during neutral statements, particularly in the left hemisphere. These findings support the clinical impression that GAD patients overreact to both pathology-specific and non-specific cues and that the reduction of anxiety attenuates the response to both types of cues.

Pharmacogenomics as molecular autopsy for postmortem forensic toxicology: genotyping cytochrome P450 2D6 for oxycodone cases.

Pharmacogenomics, the study of the impact of heritable traits on pharmacology and toxicology, may serve as an adjunct for certifying opioid fatalities. Oxycodone, frequently prescribed for the relief of moderate to severe pain, is metabolized by cytochrome P450 (CYP) 2D6, encoded by a polymorphic gene with three mutations (*3, *4, and *5) with a combined 95% allelic frequency and about 10% prevalence. Individuals with variant alleles are more susceptible to oxycodone toxicity. By assessing the prevalence of CYP2D6 polymorphisms and covariables, we hypothesized that oxycodone fatality may be partially due to poor drug metabolism caused by CYP2D6 variant alleles. From the Milwaukee County Medical Examiner's Office (MCMEO), a retrospective analysis of 15 oxycodone cases was followed by genotyping blood samples for the variant alleles by conventional and real-time PCRs. Institutional Review Board approval was obtained. Oxycodone, extracted from blood and/or urine, was quantitated by GC-MS. The results show two homozygous for 2D6*4 and four heterozygous for 2D6*4. The MCMEO was not significantly different from those in the control group (n = 26) (p > 0.05, Fisher's Exact Test). However, genotyping CYP2D6 provided a more definitive interpretation of the oxycodone toxicity in four cases. Therefore, pharmacogenomics may serve as an adjunct in the determination of the cause and manner of death in forensic toxicology and a pharmacogenomic algorithm for genotyping has been proposed.

Pharmacogenomics as an aspect of molecular autopsy for forensic pathology/toxicology: does genotyping CYP 2D6 serve as an adjunct for certifying methadone toxicity?

Pharmacogenomics, applied as an aspect of molecular autopsy, may be used as an adjunct for certifying methadone fatalities. Methadone is metabolized by cytochrome P-450 (CYP) 1A2, 3A4, and 2D6. We hypothesized that methadone toxicity may be partially due to CYP 2D6 *3, *4, and *5 variant alleles, resulting in poor drug metabolism. A retrospective analysis was performed on covariables and risk factors of 21 methadone cases from the Milwaukee County Medical Examiner's Office (1998-2000). PCR genotyping showed: one heterozygous for 2D6*3, two homozygous for 2D6*4, five heterozygous for 2D6*4, and one heterozygous for both 2D6*3 and *4. This limited number of cases showed that the prevalence of poor metabolizer was higher but not significantly different from that of a control group (n = 23) (P > 0.05, Fisher Exact Test). Thus, CYP 2D6 mutations may not yet be directly associated with methadone toxicity. However, pharmacogenomics, complementing other case findings, served as an adjunct in interpreting methadone toxicity of poor and intermediate metabolizers.

A new look at trigger point injections.

Trigger point injections are commonly practised pain interventional techniques. However, there is still lack of objective diagnostic criteria for trigger points. The mechanisms of action of trigger point injection remain obscure and its efficacy remains heterogeneous. The advent of ultrasound technology in the noninvasive real-time imaging of soft tissues sheds new light on visualization of trigger points, explaining the effect of trigger point injection by blockade of peripheral nerves, and minimizing the complications of blind injection.

Steroids in regional analgesia.

IMPORTANCE OF THE FIELD: Local injections of steroids have been widely practiced to provide regional analgesia for the treatment of a wide variety of musculoskeletal pain syndromes. However, evidence regarding the effectiveness of steroid injections is not substantial. Also, there have been reports of catastrophic complications associated with their use. AREAS COVERED IN THIS REVIEW: The evidence currently available in the literature (Database: Ovid MEDLINE 1950 to 2010) is reviewed. The areas covered include the analgesic mechanisms of steroids, indications for steroid injections and their effectiveness, as well as the risks and precautions for steroid injections. WHAT THE READER WILL GAIN: This is an up-to-date review on the clinical application of steroid injections for regional analgesia, which will give the reader an insight on how to maximize the benefits of steroids while minimizing their side effects and complications. TAKE HOME MESSAGE: Although steroid injections are generally considered effective and safe in the treatment of painful condition of limbs, their use in the treatment of chronic back pain is still controversial and serious complications have been reported. More studies on outcome and safety are warranted.

Validation of a CYP2D6 genotyping panel on the NanoChip Molecular Biology Workstation.

BACKGROUND: CYP2D6 is a highly polymorphic phase I enzyme that metabolizes 20%-25% of clinically used drugs. The objective of this study was to validate a CYP2D6 genotyping assay with the NanoChip Molecular Biology Workstation. METHODS: We genotyped 200 anonymized human DNA samples with the Pyrosequencing platform at the Medical College of Wisconsin and with the NanoChip platform at Dartmouth Medical School. We compared CYP2D6 genotypes and resolved samples with genotypic discrepancies with the Jurilab CYP2D6 duplication/deletion assay or with traditional DNA sequencing. The Jurilab assay is a long-range PCR assay used to evaluate sequence structures 3' of the CYP2D7 and CYP2D6 coding regions. For the NanoChip platform, we performed multipad addressing and duplicate runs to test the intra- and intercartridge precision, within- and between-run precision, and reproducibility of the defined genotypes. RESULTS: We used both platforms to genotype all 200 DNA samples for CYP2D6*3, *4, *5, *6, *7, *8, and gene duplication. The 2 methods showed 99.4% concordance in the genotyping results; we found only 8 discrepant genotypes among 1400 DNA analyses. Confirmatory molecular analysis of the discrepant genotypes revealed that the NanoChip assay showed better agreement. The imprecision of the NanoChip method (CV) was 8.9%-17.7%. CONCLUSIONS: This validation study of the NanoChip electronic microarray-based CYP2D6 genotyping assay revealed a CV <20% and good concordance with the Pyrosequencing method and a confirmatory sequencing method.

Pharmacogenomic genotyping methodologies.

"Personalized medicine" based on an individual's genetic makeup is slowly becoming a reality as pharmacogenomics moves from the research setting to the clinical laboratory. Concordance studies between genotype and phenotype have shown that inherited mutations in several key drug-metabolizing enzymes, such as cytochrome P450 ( CYP ) 2D6 , 2C9 , and 2C19 , result in several distinct phenotypes that lead to different individual responses following drug administration. One of the major driving forces behind pharmacogenomics and its ability to be used effectively are the technologies that are available. A beneficial genotyping test must identify most or all of the mutations that have a significant impact on the expression or function of drug-metabolizing enzymes, transporter proteins, and/or drug receptors. Selection of the appropriate technology will be based on several issues, including prior knowledge of the mutation/polymorphism, sensitivity/specificity, sample requirements, and cost. Since the future volume of pharmacogenomic testing is anticipated to be large, automation of pharmacogenomics will also become increasingly important. This paper provides an overview of current technologies available for assessing polymorphisms on a small- to large-scale basis.