Evidence against implant-derived cobalt toxicity: case report and retrospective study of serum cobalt concentrations in an orthopedic implant population.

Objectives: Cobalt (Co) exposure has been documented to result in increased erythropoiesis. To evaluate the potential for implant-derived Co toxicity, we examined the relationship between serum Co (sCo) and erythrocyte counts (ERY) in a metal-containing total-hip arthroplasty implant population.

Methods: Retrospective review of sCo concentrations identified 77 patients with concomitant ERY.

Stone composition as a function of age and sex.

Background And Objectives: Kidney stones are heterogeneous but often grouped together. The potential effects of patient demographics and calendar month (season) on stone composition are not widely appreciated.

Design, Setting, Participants, & Measurements: The first stone submitted by patients for analysis to the Mayo Clinic Metals Laboratory during 2010 was studied (n=43,545).

Thiamine deficiency in Cambodian infants with and without beriberi.

Objectives: To test the hypothesis that heavy metal toxicity and consumption of thiaminase-containing foods predispose to symptomatic thiamine deficiency.

Study Design: In a case-control study, thiamine diphosphate (TDP) blood concentrations were measured in 27 infants diagnosed with beriberi at a rural clinic, as well as their mothers and healthy Cambodian and American controls. Blood and urine levels of lead, arsenic, cadmium, mercury, and thallium were measured.

An unusual foreign body in the urinary bladder mimicking a parasitic worm.

We report an unusual case of a foreign body removed from the urinary bladder of a 63-year-old male which mimicked a parasitic worm. The foreign body was identified as an artificial fishing worm by morphological comparison to a similar commercially produced product and by infrared spectrum analysis.

Hereditary hemochromatosis: laboratory evaluation.

The condition of hereditary hemochromatosis (HH) is caused by gene-dependent protein abnormalities involved in iron absorption, storage, or modulation of iron; these abnormalities result in iron overload. The clinical laboratory plays a significant role in case finding, diagnostic validation, and monitoring HH therapy. Elevated serum iron, transferrin saturation, and ferritin suggest HH, but results can also indicate other forms of hepatocyte injury such as alcoholic or viral hepatitis, or other inflammatory disorders involving the liver.

Fluoride excess and periostitis in transplant patients receiving long-term voriconazole therapy.

Background: We describe a heart transplant patient with painful periostitis and exostoses who was receiving long-term therapy with voriconazole, which is a fluoride-containing medication. Elevated plasma and bone fluoride levels were identified. Discontinuation of voriconazole therapy led to improvement in pain and reduced fluoride and alkaline phosphatase levels.

Effect of cytochrome P450 enzyme polymorphisms on pharmacokinetics of venlafaxine.

This study examines the relationship between blood concentrations of venlafaxine and its active metabolite, O-desmethyl venlafaxine (ODV), and genetic variants of the cytochrome P450 enzymes CYP2D6 and CYP2C19 in human subjects. Trough blood concentrations were measured at steady state in patients treated with venlafaxine extended release in a clinical practice setting. CYP2D6 and CYP2C19 genotypes were converted to activity scores based on known activity levels of the two alleles comprising a genotype.

Quantification of gadolinium in fresh skin and serum samples from patients with nephrogenic systemic fibrosis.

Background: Nephrogenic systemic fibrosis (NSF) is a rare, potentially fatal fibrosing disorder associated with renal insufficiency and gadolinium (Gd)-based contrast exposure. The cause remains unknown. To date, all efforts to investigate skin Gd concentrations in patients with NSF have been performed on paraffin-embedded samples, and Gd deposition has not been correlated with disease activity by a statistically significant analysis.

Warfarin genotyping reduces hospitalization rates results from the MM-WES (Medco-Mayo Warfarin Effectiveness study).

Objectives: This study was designed to determine whether genotype testing for patients initiating warfarin treatment will reduce the incidence of hospitalizations, including those due to bleeding or thromboembolism.

Background: Genotypic variations in CYP2C9 and VKORC1 have been shown to predict warfarin dosing, but no large-scale studies have prospectively evaluated the clinical effectiveness of genotyping in naturalistic settings across the U.S.

Warfarin sensitivity genotyping: a review of the literature and summary of patient experience.

The antithrombotic benefits of warfarin are countered by a narrow therapeutic index that contributes to excessive bleeding or cerebrovascular clotting and stroke in some patients. This article reviews the current literature describing warfarin sensitivity genotyping and compares the results of that review to the findings of our study in 189 patients at Mayo Clinic conducted between June 2001 and April 2003. For the review of the literature, we identified relevant peer-reviewed articles by searching the Web of Knowledge using key word warfarin-related adverse event.

Chelation of gadolinium with deferoxamine in a patient with nephrogenic systemic fibrosis.

A 65-year-old female with biopsy-confirmed nephrogenic systemic fibrosis (NSF) received a kidney transplantation. Despite good kidney function, her symptoms continued to progress. Deferoxamine was administered intramuscularly at 500 mg/day and later 1000 mg/day after 1 week with no adverse effects.

Effect of high-dose nicotine patch therapy on tobacco withdrawal symptoms among smokeless tobacco users.

No pharmacotherapies have been shown to increase long-term (> or = 6-month) abstinence rates among smokeless tobacco (ST) users. Available evidence suggests that underdosing may occur with standard-dose nicotine replacement therapy (NRT) in ST users. We investigated the effect of high-dose nicotine therapy on tobacco withdrawal symptoms among ST users in a randomized, controlled clinical pilot study.

Nicotine percentage replacement among smokeless tobacco users with nicotine patch.

To obtain preliminary evidence on the safety and efficacy of high dose nicotine patch therapy among smokeless tobacco (ST) users who consume > or =3 cans of ST per week, we conducted a randomized, placebo-controlled clinical trial with 42 ST users randomized to nicotine patch doses of 21, 42, and 63 mg/day or placebo. Serum nicotine concentrations were measured during ad libitum ST use and nicotine replacement therapy, and percentages of nicotine replacement were calculated. We observed substantial inter-subject variability in nicotine concentrations with ad lib ST use.

Alternative to ganglionic blockade with anticholinergic and alpha-2 receptor agents.

The ganglionic blocking agent trimethaphan (TMP) is no longer produced. Therefore, a need exists for alternative pharmacological approaches to investigate baroreflex control of the circulation. The aim of the present study was to examine baroreflex-mediated cardiovascular responses during the administration of a muscarinic receptor antagonist (glycopyrrolate; GLY: ) and a selective alpha-2 receptor agonist (dexmedetomidine; DEX: ) and to compare responses to ganglionic blockade with TMP.

Differentiation of amphetamine/methamphetamine and other cross-immunoreactive sympathomimetic amines in urine samples by serial dilution testing.

Background: Immunoassay-based screening for amphetamines has a variable positive predictive value (PPV) for detecting amphetamine abuse. The lack of immunoassay specificity necessitates confirmatory testing by gas chromatography-mass spectrometry (GC/MS), but the technical complexity and expense of GC/MS limit its availability. Physicians may make decisions regarding patient disposition based on unverified results.

Iqmik: a form of smokeless tobacco used among Alaska natives.

Objectives: To describe a homemade form of smokeless tobacco known as Iqmik used among Alaska Natives residing in western Alaska.

Methods: Individual and small-group interviews were conducted with 23 adult Alaska Natives. The major themes from the interview data were summarized.

Iqmik--a form of smokeless tobacco used by pregnant Alaska natives: nicotine exposure in their neonates.

Objective: To determine the concentration of nicotine and cotinine in maternal blood and neonatal cord blood among pregnant Alaska Native women and to assess the neonates for neurobehavioral effects.

Methods: In a nonrandomized, clinical observational pilot trial, 60 pregnant Alaska Native women were enrolled for assessment of Iqmik (a mixture of leaf tobacco and ash) and other tobacco use during pregnancy and at delivery. Neonatal cord blood, nicotine and cotinine concentrations were obtained, and neonatal neurobehavioral effects were assessed using the Lipsitz scale.

Variability in hepatic iron concentration in percutaneous needle biopsy specimens from patients with transfusional hemosiderosis.

In patients with sickle cell disease or beta-thalassemia receiving RBC transfusions for a long period, a precise knowledge of the liver iron concentration (LIC) is essential for treatment. Patients underwent LIC and liver pathology assessment by duplicate biopsies in 2 passes from the same local liver site. Fresh tissue cores in trace element-free containers and tissues from dissolved paraffin-embedded cores were analyzed.

Cotinine as a biomarker of systemic nicotine exposure in spit tobacco users.

Unlike cigarette smokers, spit tobacco (ST) users absorb a significant amount of nicotine through the gastrointestinal tract while swallowing tobacco juice. The majority of the absorbed nicotine is rapidly converted to cotinine during first-pass hepatic metabolism. This process potentially compromises the utility of cotinine as a biomarker for systemic nicotine exposure in ST users.

National academy of clinical biochemistry laboratory medicine practice guidelines: recommendations for the use of laboratory tests to support poisoned patients who present to the emergency department.

Background: Exposure to drugs and toxins is a major cause for patients' visits to the emergency department (ED).

Methods: Recommendations for the use of clinical laboratory tests were prepared by an expert panel of analytical toxicologists and ED physicians specializing in clinical toxicology. These recommendations were posted on the world wide web and presented in open forum at several clinical chemistry and clinical toxicology meetings.

Simultaneous analysis of nicotine, nicotine metabolites, and tobacco alkaloids in serum or urine by tandem mass spectrometry, with clinically relevant metabolic profiles.

Background: Assessment of nicotine metabolism and disposition has become an integral part of nicotine dependency treatment programs. Serum nicotine concentrations or urine cotinine concentrations can be used to guide nicotine patch dose to achieve biological concentrations adequate to provide the patient with immediate relief from nicotine withdrawal symptoms, an important factor in nicotine withdrawal success. Absence of nicotine metabolites and anabasine can be used to document abstinence from tobacco products, an indicator of treatment success.