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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.Methods: This national, prospective, comparative effectiveness study compared the 6-month incidence of hospitalization in patients receiving warfarin genotyping (n = 896) versus a matched historical control group (n = 2,688). To evaluate for temporal changes in the outcomes of warfarin treatment, a secondary analysis compared outcomes for 2 external control groups drawn from the same 2 time periods.Results: Compared with the historical control group, the genotyped cohort had 31% fewer hospitalizations overall (adjusted hazard ratio [HR]: 0.69, 95% confidence interval [CI]: 0.58 to 0.82, p < 0.001) and 28% fewer hospitalizations for bleeding or thromboembolism (HR: 0.72, 95% CI: 0.53 to 0.97, p = 0.029) during the 6-month follow-up period. Findings from a per-protocol analysis were even stronger: 33% lower risk of all-cause hospitalization (HR: 0.67, 95% CI: 0.55 to 0.81, p < 0.001) and 43% lower risk of hospitalization for bleeding or thromboembolism (HR: 0.57, 95% CI: 0.39 to 0.83, p = 0.003) in patients who were genotyped. During the same period, there was no difference in outcomes between the 2 external control groups.Conclusions: Warfarin genotyping reduced the risk of hospitalization in outpatients initiating warfarin. (The Clinical and Economic Impact of Pharmacogenomic Testing of Warfarin Therapy in Typical Community Practice Settings [MHSMayoWarf1]; NCT00830570). [ABSTRACT FROM AUTHOR]

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. A chemical analysis was conducted of the alkalinity of a sample of fungus ash used to prepare Iqmik. RESULTS: Few adverse health effects of using Iqmik were reported. The alkalinity of the sample of fungus ash was high (pH=10.9). CONCLUSION: The high alkalinity of Iqmik may contribute to the higher rates of tobacco use in this population. [ABSTRACT FROM AUTHOR]

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. Statistical analysis was performed to determine if there was a significant difference in ERY for patients divided into clinically relevant sCo ranges. A single detailed case review of a patient with a loose mal-positioned acetabular component and significantly elevated sCo was also performed for symptoms thought to arise from Co toxicity., Results: Statistical difference in ERY was not observed between patients with significantly elevated (>10 ng/mL), elevated (4-10 ng/mL), modestly elevated (1.0-3.9 ng/mL), or normal (<1.0 ng/mL) sCo. While the detailed case report was unremarkable for any of the clinical symptoms previously reported to be associated with Co toxicity and no increase in ERY was observed, this patient's sCo was 84 ng/mL., Conclusions: Increased erythropoiesis was not observed in patients with implant-derived increased sCo. Even with a sCo 100 × the upper-limit of normal, the patient presented did not have increased ERY nor exhibit any symptoms ascribed with Co toxicity., (Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

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). Stones were classified in the following order: any struvite, any cystine, any uric acid, any brushite, majority (≥50%) calcium oxalate, or majority (≥50%) hydroxyapatite., Results: Calcium oxalate (67%) was the most common followed by hydroxyapatite (16%), uric acid (8%), struvite (3%), brushite (0.9%), and cystine (0.35%). Men accounted for more stone submissions (58%) than women. However, women submitted more stones than men between the ages of 10-19 (63%) and 20-29 (62%) years. Women submitted the majority of hydroxyapatite (65%) and struvite (65%) stones, whereas men submitted the majority of calcium oxalate (64%) and uric acid (72%) stones (P<0.001). Although calcium oxalate stones were the most common type of stone overall, hydroxyapatite stones were the second most common before age 55 years, whereas uric acid stones were the second most common after age 55 years. More calcium oxalate and uric acid stones were submitted in the summer months (July and August; P<0.001), whereas the season did not influence other stone types., Conclusions: It is well known that calcium oxalate stones are the most common stone type. However, age and sex have a marked influence on the type of stone formed. The higher number of stones submitted by women compared with men between the ages of 10 and 29 years old and the change in composition among the elderly favoring uric acid have not been widely appreciated. These data also suggest increases in stone risk during the summer, although this is restricted to calcium oxalate and uric acid stones., (Copyright © 2014 by the American Society of Nephrology.)

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. Local food samples were analyzed for thiaminase activity., Results: Mean TDP level among cases and Cambodian controls was 48 and 56 nmol/L, respectively (P = .08) and was 132 nmol/L in American controls (P < .0001 compared with both Cambodian groups). Mean TDP level of mothers of cases and Cambodian controls was 57 and 57 nmol/L (P = .92), and was 126 nmol/L in American mothers (P < .0001 compared with both Cambodian groups). Cases (but not controls) had lower blood TDP levels than their mothers (P = .02). Infant TDP level decreased with infant age and was positively associated with maternal TDP level. Specific diagnostic criteria for beriberi did not correlate with TDP level. There was no correlation between heavy metal levels and either TDP level or case/control status. No thiaminase activity was observed in food samples., Conclusions: Thiamine deficiency is endemic among infants and nursing mothers in rural southeastern Cambodia and is often clinically inapparent. Neither heavy metal toxicity nor consumption of thiaminase-containing foods account for thiamine deficiency in this region., (Copyright © 2012 Mosby, Inc. All rights reserved.)

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.

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. In the context of elevated serum iron, transferrin saturation, and ferritin, and after ruling out secondary causes of iron overload, HFE gene evaluation is the preferred test to confirm the diagnosis of HH. However, 5% to 15% of patients with phenotypic HH do not have HFE gene mutations. In these cases, MRI evaluation or liver biopsy with iron quantification is indicated. The clinical role of hepcidin, the iron modulating protein, is undetermined at this time. Because hepcidin also plays a key role in antimicrobial and inflammatory activities, interpretation of hepcidin serum or urine concentration will require thorough understanding of its complex role in iron regulation., (Copyright © 2011 Elsevier B.V. All rights reserved.)

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., Methods: To determine whether voriconazole is a cause of fluoride excess, we measured plasma fluoride levels in 10 adult post-transplant patients who had received voriconazole for at least 6 months and 10 post-transplant patients who did not receive voriconazole. To assess the effect of renal insufficiency on fluoride levels in subjects receiving voriconazole, half were recruited on the basis of a serum creatinine level of ≥1.4 mg/dL on their most recent measurement, whereas the other 5 subjects receiving voriconazole had serum creatinine levels <1.4 mg/dL. All control subjects had serum creatinine levels of ≥1.4 mg/dL. Patients were excluded from the study if they received a fluorinated pharmaceutical other than voriconazole., Results: All subjects who received voriconazole had elevated plasma fluoride levels, and no subjects in the control group had elevated levels (14.32 μmol/L ± 6.41 vs 2.54 ± 0.67 μmol/L; P<.001). Renal function was not predictive of fluoride levels. Plasma fluoride levels remained significantly higher in the voriconazole group after adjusting for calcineurin inhibitor levels and doses. Half of the voriconazole group subjects had evidence of periostitis, including exostoses in 2 patients. Discontinuation of voriconazole therapy in patients with periostitis resulted in improvement of pain and a reduction in alkaline phosphatase and fluoride levels., Conclusions: Voriconazole is associated with painful periostitis, exostoses, and fluoride excess in post-transplant patients with long-term voriconazole use.

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. After adjusting for drug dose and gender effects, higher CYP2D6 and CYP2C19 activity scores were significantly associated with lower venlafaxine concentrations (P < 0.001 for each). Only CYP2D6 was associated with the concentration of ODV (P < 0.001), in which genotypes with more active alleles were associated with higher ODV concentrations. The sum of venlafaxine plus ODV concentration showed the same pattern as venlafaxine concentrations with CYP2D6 and CYP2C19 genotypes with higher activity scores being associated with a lower venlafaxine plus ODV concentration (2D6 P = 0.01; 2C19 P < 0.001). Because allelic variants in both CYP2D6 and CYP2C19 influence the total concentration of the active compounds venlafaxine and ODV, both CYP2D6 and CYP2C19 genotypes should be considered when using pharmacogenomic information for venlafaxine dose alterations.

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., Objective: We sought to: (1) quantify Gd concentration in fresh tissue skin biopsy specimens; (2) quantify and compare synchronous Gd concentration of affected skin and unaffected skin in patients with NSF (n = 13) with a control group (n = 13); and (3) quantify serum Gd., Methods: We used inductively coupled plasma mass spectrometry., Results: In patients with NSF, the mean ratio of paired Gd concentrations of affected skin to unaffected skin was 23.1, ranging from 1.2 to 88.9. Mean serum Gd concentrations in patients with NSF were 4.8 ng/mL, which is more than 10 times the level in control patients. A statistically significant correlation existed between serum and affected skin Gd concentrations (r(2) = .74, P < .0001)., Limitations: Because of the feasibility of this study, the main limitation was the small sample size (n = 13 affected and 13 control)., Conclusions: Determination of Gd concentrations in fresh skin samples and serum using inductively coupled plasma mass spectrometry demonstrates significant differences in the amounts of Gd in involved versus nonlesional skin of patients with NSF. This supports the role of differential free Gd deposition from Gd-based contrast in the pathogenesis of NSF., (Copyright © 2009 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

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. For the 189 Mayo Clinic patients initiating warfarin therapy to achieve a target international normalized ratio (INR) in the range of 2.0 to 3.5, we analyzed the CYP2C9 (cytochrome P450 2C9) and VKORC1 (vitamin K epoxide reductase complex, subunit 1) genetic loci to study the relationship among the initial warfarin dose, steady-state dose, time to achieve steady-state dose, variations in INR, and allelic variance. Results were compared with those previously reported in the literature for 637 patients. The relationships between allelic variants and warfarin sensitivity found in our study of Mayo Clinic patients are fundamentally the same as in those reported by others. The Mayo Clinic population is predominantly white and shows considerable allelic variability in CYP2C9 and VKORC1. Certain of these alleles are associated with increased sensitivity to warfarin. Polymorphisms in CYP2C9 and VKORC1 have a considerable effect on warfarin dose in white people. A correlation between steady-state warfarin dose and allelic variants of CYP2C9 and VKORC1 has been demonstrated by many previous reports and is reconfirmed in this report. The allelic variants found to most affect warfarin sensitivity are CYP2C9*1*1-VKORC1BB (less warfarin sensitivity than typical); CYP2C9*1*1-VKORC1AA (considerable variance in INR throughout initiation); CYP2C9*1*2-VKORC1AB (more sensitivity to warfarin than typical); CYP2C9*1*3-VKORC1AB (much more sensitivity to warfarin than typical); CYP2C9*1*2-VKORC1AB (much more sensitivity to warfarin than typical); CYP2C9*1*3-VKORC1AA (much more sensitivity to warfarin than typical); and CYP2C9*2*2-VKORC1AB (much more sensitivity to warfarin than typical). Although we were unable to show an association between allelic variants and initial warfarin dose or dose escalation, an association was seen between allelic variant and steady-state warfarin dose. White people show considerable variance in CYP2C9 allele types, whereas people of Asian or African descent infrequently carry CYP2C9 allelic variants. The VKORC1AA allele associated with high warfarin sensitivity predominates in those of Asian descent, whereas white people and those of African descent show diversity, carrying either the VKORC1BB, an allele associated with low warfarin sensitivity, or VKORC1AB or VKORC1AA, alleles associated with moderate and high warfarin sensitivity, respectively.

The purpose of this study was to compare ganglionic blockade with trimethaphan (TMP) and an alternative drug strategy using combined muscarinic antagonist (glycopyrrolate, GLY) and alpha-2 agonist (dexmedetomidine, DEX). Protocol 1: incremental phenylephrine was administered during control and combined GLY-DEX, or control and TMP on two control combined GLY and DEX or TMP infusion on two randomized days. Protocol 2: muscle sympathetic nerve activity (MSNA) and the baroreflex MSNA relationship was determined before and after GLY-DEX. Blood pressure was higher with GLY-DEX (99+/-3 mm Hg) and lower with TMP (78+/-3 mm Hg) relative to control (GLY-DEX: 90+/-2 mm Hg; TMP: 91+/-2 mm Hg; P<0.05). Incremental phenylephrine increased pressure during GLY-DEX (P<0.01 vs control) and TMP (P<0.01 vs control) to a similar degree. Both GLY-DEX and TMP infusion inhibited norepinephrine release (P<0.01 vs control). GLY-DEX inhibited baseline MSNA (P<0.05) and baroreflex changes in MSNA (P<0.01). We conclude that the GLY-DEX alternative drug strategy can be used as a reasonable alternative to pharmacologic ganglionic blockade to examine autonomic cardiovascular control.

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. The mean percentage replacement of ad lib ST use serum nicotine concentrations approximated 100% with the 42 mg/day patch dose (mean+/-S.D., 98.4%+/-45%). Dosing with the 21 mg/day nicotine patch was associated with mean "under-replacement" (53.2%+/-17.1%), and the 63 mg/day nicotine was associated with mean "over-replacement" (159.2%+/-121.9%). We observed symptoms of nausea consistent with nicotine toxicity in two subjects in the 63 mg/day group while no subjects in the 42 mg/day reported these symptoms. We conclude that the use of 42 mg/day nicotine patch therapy is safe and should be considered as initial therapy in the clinical setting among ST users who use > or =3 cans/week.

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. We hypothesized that combined GLY-: DEX: would inhibit the baroreflex similar to TMP. Ten volunteers participated in two study days and were instrumented with pulse oximeter, nasal cannula, ECG, continuous blood pressure monitoring (Finapres), and I.V. catheter for drug infusions. Each study day consisted of a control condition followed by either combined GLY: -DEX: or TMP on alternating days. A Valsalva maneuver was performed under each condition with every subject and six subjects received bolus phenylephrine (25 mug) during GLY: -DEX: and TMP. Combined GLY: -DEX: increased (P < 0.05) blood pressure (99 +/- 4 mmHg) and heart rate (99 +/- 3 bpm) relative to control condition (BP: 90 +/- 2 mmHg; HR: 64 +/- 3 bpm) and TMP infusion decreased (P < 0.05) blood pressure (79 +/- 3 mmHg) while increasing heart rate (88 +/- 3 bpm). Valsalva maneuver elicited a persistent drop in arterial pressure (no phase IIb recovery) with the absence of a phase IV overshoot during both GLY: -DEX: and TMP conditions. Phenylephrine increased systolic pressure 34 +/- 4 mmHg under GLY: -DEX: and 23 +/- 3 mmHg with TMP (P < 0.05). Heart rate only decreased 1 +/- 2 bpm during GLY: -DEX: and 1 +/- 1 bpm with TMP. Taken together, our results suggest that GLY: -DEX: is a reasonable alternative to TMP for baroreflex inhibition.

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. A total of 42 ST users using at least 3 cans or pouches per week were randomized to nicotine patch doses of 63, 42, or 21 mg/day or placebo for 8 weeks. Multiple daily assessments of tobacco withdrawal and nicotine toxicity were obtained with an electronic diary. During the first week of nicotine patch therapy, we observed a dose-response relationship such that higher nicotine patch doses were associated with less decreased arousal (chi2 = 6.87, p = .009), less negative affect (chi2 = 3.85, p = .05), and less restlessness (chi2 = 3.90, p = .048). During the second week, higher nicotine patch doses were associated with less decreased arousal (chi2 = 6.77, p = .009). Overall, the frequency of nicotine toxicity symptoms did not differ by dose group. Of specific symptoms, nausea was observed to be more frequent in the 63 mg/day dose group compared with placebo (p = .035). In conclusion, high-dose nicotine patch therapy resulted in a greater reduction of tobacco withdrawal symptoms among ST users using at least 3 cans per week. High-dose nicotine patch therapy is safe and well tolerated in this population of tobacco users.

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. In this study we assessed the utility of using dose-response properties to distinguish urine samples containing amphetamines from samples containing cross-immunoreactive species., Methods: Urine was supplemented with known concentrations of amphetamine, methamphetamine, methylenedioxymethamphetamine (MDMA), or pseudoephedrine. Using a series of dilutions, we determined the maximum change in rate over the fractional change in concentration for each compound in the Emit II amphetamine/methamphetamine immunoassay. Patient urine samples that screened positive for amphetamines were diluted 1:1, 1:10, and 1:20, and maximum slope estimates within the dynamic assay range were determined. An optimal slope cutoff that differentiated samples containing (meth)amphetamine from those containing cross-reacting species was determined by ROC analysis., Results: The slope of the dose response was largest for amphetamine and methamphetamine, followed by MDMA and pseudoephedrine. The optimum slope cutoff for identifying patient specimens containing (meth)amphetamine was 320 (sensitivity, 96%; specificity, 90%; PPV, 92%). High concentrations of less reactive compounds may mask low concentrations of amphetamines., Conclusions: Use of the slope of the dose-response relationship in patient urine specimens can enhance the PPV of presumptive positive immunoassay results but does not exclude the presence of low amphetamine concentrations in samples containing high concentrations of cross-reactive species.

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., Results: At delivery, there were 22 subjects who reported using only Iqmik, and 10 who used other tobacco products. Subjects who reported using only Iqmik prior to delivery had higher concentrations of cotinine (167+/-116 vs. 81+/-100) in maternal blood (rank sum test, p=0.036) and higher concentrations of nicotine (8.4+/-7.3 vs. 4.4+/-5.1, p=0.048) and cotinine (153+/-115 vs. 70+/-95, p=0.048) in cord blood compared to subjects who reported using other tobacco products. Neurobehavioral signs as assessed by the Lipsitz score were increased in neonates born to mothers using only Iqmik (3.7+/-1.8, p=0.011), or to mothers using other tobacco products (3.4+/-1.4, p=0.034) compared to neonates born to women who reported no tobacco use (1.8+/-1.4)., Conclusions: Mothers who use Iqmik and their neonates have higher cotinine concentrations compared to mothers who use cigarettes and/or other forms of tobacco. Neurobehavioral signs occur in neonates born to women who use Iqmik but also in neonates born to mothers who use other forms of tobacco during pregnancy.

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. LIC measurements in each of 2 paraffin-embedded cores did not differ significantly (median, 12,455 vs 12,153 microg/g dry weight; n = 29). A significant difference was observed when 1 fresh tissue sample and 1 paraffin-embedded core were analyzed (median, 11,716 vs 12,864 microg/g dry weight; n = 16; P < .001) with a median disagreement between LIC measurements of 23.0%. We found high agreement in LICs between liver biopsy specimens processed by the paraffin-embedding technique but overestimation of LICs in comparison with desiccated fresh tissue samples.

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. To investigate this question, we correlated nicotine and cotinine concentrations with clinical measures of ST use in 68 daily ST users enrolled in a non-nicotine pharmacologic intervention trial. We found that a higher frequency of swallowing tobacco juice (P=.007) was an independent predictor of higher serum cotinine concentrations. Serum nicotine concentrations, on the other hand, were not correlated with a higher frequency of swallowing. In the absence of a reliable way to measure frequency of swallowing, we conclude that cotinine should not be used for guiding clinical decisions that depend upon a precise quantification of systemic nicotine exposure, such as tailored nicotine replacement therapy.

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., Results: A menu of important stat serum and urine toxicology tests was prepared for clinical laboratories who provide clinical toxicology services. For drugs-of-abuse intoxication, most ED physicians do not rely on results of urine drug testing for emergent management decisions. This is in part because immunoassays, although rapid, have limitations in sensitivity and specificity and chromatographic assays, which are more definitive, are more labor-intensive. Ethyl alcohol is widely tested in the ED, and breath testing is a convenient procedure. Determinations made within the ED, however, require oversight by the clinical laboratory. Testing for toxic alcohols is needed, but rapid commercial assays are not available. The laboratory must provide stat assays for acetaminophen, salicylates, co-oximetry, cholinesterase, iron, and some therapeutic drugs, such as lithium and digoxin. Exposure to other heavy metals requires laboratory support for specimen collection but not for emergent testing., Conclusions: Improvements are needed for immunoassays, particularly for amphetamines, benzodiazepines, opioids, and tricyclic antidepressants. Assays for new drugs of abuse must also be developed to meet changing abuse patterns. As no clinical laboratory can provide services to meet all needs, the National Academy of Clinical Biochemistry Committee recommends establishment of regional centers for specialized toxicology testing.

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., Methods: The procedure was designed to quantify nicotine, cotinine, trans-3'-hydroxycotinine, anabasine, and nornicotine in human serum or urine. The technique required simple extraction of the sample with quantification by HPLC-tandem mass spectrometry., Results: The procedure for simultaneous analysis of nicotine, its metabolites, and tobacco alkaloids simultaneously quantified five different analytes. Test limit of quantification, linearity, imprecision, and accuracy were adequate for clinical evaluation of patients undergoing treatment for tobacco dependency. The test readily distinguished individuals who had no exposure to tobacco products from individuals who were either passively exposed or were abstinent past-tobacco users from those who were actively using a tobacco or nicotine product., Conclusions: Nicotine, cotinine, trans-3'-hydroxycotinine, nornicotine, and anabasine can be simultaneously and accurately quantified in either serum or urine by HPLC-tandem mass spectrometry with imprecision <10% at physiologic concentrations and limits of quantification ranging from 0.5 to 5 micro g/L. Knowledge of serum or urine concentrations of these analytes can be used to guide nicotine replacement therapy or to assess tobacco abstinence in nicotine dependency treatment. These measurements are now an integral part of the clinical treatment and management of patients who wish to overcome tobacco dependence.

Objective: To describe smoking abstinence and fetal effects of pregnant smokers who received 8 weeks of nicotine patch therapy., Methods: One-sample study of 21 pregnant women smoking > or = 15 cigarettes/day during their third trimester of pregnancy despite physician advice to stop. Nicotine patch therapy (22 mg/24 h) was initiated during the first day of a 4-day in-hospital study and continued for a total of 8 weeks. Subjects returned weekly until delivery, at 4 weeks after delivery, and at 6 and 12 months after patch therapy. Fetal growth and well-being were assessed using ultrasound examinations and non-stress tests., Results: Eight of 21 subjects completed all 8 weeks of patch therapy according to the protocol. Five subjects (24%) discontinued using the nicotine patch, owing to adverse skin reactions. There were eight subjects (38%) who were biochemically confirmed abstinent from smoking at the time of delivery; of these, seven were continuously abstinent from the start of patch therapy. Centile weight for gestational age did not change significantly over time for 12 subjects with serial ultrasound measurements available at baseline, 4 weeks and 8 weeks following initiation of patch therapy. In all cases, non-stress tests remained reactive or became reassuring with observation. No significant preterm deliveries occurred (gestational ages of 36.3-41.1 weeks). Three infants suffered severe neonatal morbidity; however, these problems were unrelated to nicotine patch therapy., Conclusion: Nicotine patch therapy has potential benefit for pregnant smokers who continue to smoke despite physician advice to stop.

The measurement of the unbound or free phenytoin concentration is indicated in several situations, including uremia. In patients with uremia, metabolites of phenytoin and other substances accumulate and can displace phenytoin from its protein binding sites, with a consequent increase in the free fraction of drug. Some of the phenytoin metabolites that accumulate in uremia can cross-react with phenytoin immunoassays. In this study the authors evaluated four free phenytoin immunoassays compared with a high-performance liquid chromatography (HPLC) method: the Roche COBAS Integra, the Syva EMIT 2000, the Opus INNOFLUOR, and the Abbott TDx. All four methods demonstrated good precision, with interday coefficients of variation of < or = 5% and comparable recoveries using quality control material. Two of the methods, the EMIT 2000 and COBAS Integra, showed excellent agreement with the HPLC method using samples from patients both with normal renal function and with renal insufficiency. The other two methods, the INNOFLUOR and TDx, showed average positive biases for the therapeutic range of 3-7% and 21-22%, respectively, compared with the HPLC method for samples from patients with normal renal function, and average positive biases of 24-32% and 75-81%, respectively, with samples from patients with uremia.

Smoking is a major risk factor for failure of coronary artery bypass grafts (CABG). Experiments were designed to determine effects of transdermal nicotine, independent of smoking, on structure and function of CABG. Saphenous veins were placed as CABG in untreated dogs (control) or in dogs treated with transdermal nicotine (one 11-mg or two 22-mg patches/day) for 5 wk. Serum nicotine and plasma nitric oxide were measured. Grafts were removed and prepared for organ chamber studies and histology. Serum nicotine averaged 12.1 and 118.7 ng/ml in the 11 mg/day and 44 mg/day groups, respectively. Plasma nitric oxide was higher in dogs treated with 11 mg/day doses compared with controls. In organ chamber studies, endothelium-dependent relaxations to thrombin and A-23187 and endothelium-independent relaxations to nitric oxide were greatest in grafts from dogs treated with 11 mg/day doses. Intimal thickness of the grafts were similar among groups. However, staining for bone sialoprotein was increased in the media of grafts from the 11 mg/day treatment group. These data suggest that transdermal nicotine in doses comparable and double to those used for conventional smoking cessation treatment in humans does not adversely affect early patency of canine CABG up to 4 wk postoperatively. Transdermal nicotine, however, may increase production of and response to nitric oxide in bypass grafts.

The mesolimbic dopamine system is thought to be a critical substrate for drugs of addiction including nicotine. Since dopamine may play a critical role in mediating the reinforcing effects of nicotine, we hypothesized that administering levodopa in its therapeutic form (carbidopa/levodopa) might be effective for smoking cessation by replacing the effects of dopamine that smokers may seek during smoking. A pilot open-label study using carbidopa/levodopa for smokers wanting to stop smoking was carried out at the Mayo Clinic Nicotine Research Center, Rochester, MN. The dosing schedule was one tablet TID for 1 week, 1 1/2 tablets TID for 1 week, then two tablets TID for 6 weeks. Each tablet contained 25 mg of carbidopa and 100 mg of levodopa. The subjects were 40 adult smokers smoking > or = 20 cigarettes per day for 3 or more years. Self-reported abstinence from smoking was confirmed by expired air CO level of < or = 8 ppm. Nicotine withdrawal symptoms were assessed at baseline and daily during the medication phase. Smoking abstinence rates and withdrawal symptom relief were compared to the placebo (n = 153) arm of a previously reported bupropion smoking cessation trial. The biochemically confirmed, 7-day point-prevalence smoking abstinence rate at the end of carbidopa/levodopa treatment was 20.0% versus 19.0% for the placebo group (p > 0.10), and 12.5% of the carbidopa/levodopa group were abstinent versus 15.7% for the placebo group (p > 0.10) at 6 months. Subjects from both studies had significant increases in withdrawal scores from baseline, but there were no significant differences between the two groups at any time period. We found no differences in smoking abstinence rates or nicotine withdrawal symptom relief in smokers receiving carbidopa/levodopa compared to placebo. Despite the theoretical reasons why carbidopa/levodopa might be effective as a pharmacological adjunct in treating smokers, it was not observed in this group of smokers at this dose.

Objective: The aims of this study were (1) to determine whether nicotine patch therapy for pregnant women smokers acutely compromises fetal well-being and (2) to determine the serum and urine nicotine and cotinine levels in pregnant women while smoking, while abstinent from smoking, and while receiving nicotine patch therapy compared with levels in a historical control group of nonpregnant women smokers who abstained from smoking while receiving comparable doses of nicotine patch therapy., Study Design: Pregnant cigarette smokers (n = 21) aged >/=18 years whose fetuses were beyond 24 weeks' gestational age were recruited for this 1-sample, repeated-measures study. Serial measurements of the mother and fetus were made at baseline while the mother was smoking, while abstaining from smoking, and while using nicotine patch therapy for 4 days in a special care hospital unit. Nonpregnant women smokers of similar age were used for comparison. Morning and afternoon serum and 24-hour urine levels of nicotine and cotinine were obtained during hospitalization. Indicators of fetal well-being assessed were fetal heart rate and reactivity, systolic/diastolic ratio of blood flow in the umbilical artery, and fetal activity seen on ultrasonography and quantitated as biophysical profiles., Results: No evidence of fetal compromise was seen during the inpatient phase while nicotine patch therapy was administered. Steady state (inpatient day 4) serum levels of nicotine were similar to smoking levels and to those seen in historical control subjects (ie, nonpregnant women of child-bearing age who were abstinent from smoking and who used the same nicotine patch). Morning serum cotinine levels were significantly higher (P =.038) in the nonpregnant subjects than in the pregnant subjects, whereas afternoon levels were not significantly different. Steady state urinary levels of nicotine and cotinine were also not significantly different in pregnant versus nonpregnant patients. On inpatient days 2, 3, and 4, when the women were not smoking and were wearing the nicotine patch, the morning fetal heart rates were significantly reduced relative to baseline when the subjects were smoking., Conclusions: Nicotine patch therapy was not found to be associated with indications of fetal compromise during the in-hospital phase of nicotine patch therapy in pregnant smokers who were abstaining. Although not conclusive because of the small sample sizes, serum nicotine levels (morning and afternoon) appear similar in pregnant and nonpregnant subjects and similar for both groups when smoking (baseline) as compared to the steady state of nicotine patch use.

Background: Antiretroviral therapy for HIV-1 infection has become increasingly complex. The availability of new and potent drugs and progress in understanding the pathogenesis of HIV-1 infection have led to the establishment of new treatment paradigms. The varying dosing regimens, associated toxicities, and the potential for drug-drug and food-drug interactions further complicate treatment. This complexity contributes to patient nonadherence. Because clinicians have no tools to monitor adherence or drug-drug interactions and because response requires that therapy exceed the known inhibiting concentration, serum monitoring of antiretroviral therapy may play a role in improving treatment of HIV-1 infection. We report methods to quantify serum concentrations of antiretroviral drugs used to treat HIV-1 infection, precision and interference studies of these methods, and results observed in a pilot evaluation of blood serum concentrations from 12 human subjects., Methods: HPLC offers adequate sensitivity to measure peak or trough serum concentrations of delavirdine, lamivudine, nevirapine, indinavir, nelfinavir, ritonavir, and saquinavir and peak serum concentrations of stavudine, zidovudine, and didanosine with reasonable precision., Results: Peak indinavir serum concentrations in most patients were in the range of 1-10 mg/L, and trough concentrations were in the range of 0.1-0.5 mg/L. Peak stavudine concentrations were in the range of 0.3-1.3 mg/L, and trough concentrations were in the range of 0.1-0.5 mg/L. Peak zidovudine concentrations were in the range of 0.1-1.1 mg/L., Conclusions: Because this was a blood serum concentration-seeking pilot study to evaluate analytic performance, we do not report on the correlation of drug response to blood concentration. However, the concentrations observed in patients are generally consistent with blood concentrations reported from studies of monotherapy.

Capillary blood sampling as a means of monitoring blood cyclosporine levels has replaced venipuncture in some medical centers. As the validity of capillary venipuncture for analysis of cyclosporine has not been documented, we sought to validate the capillary blood collection technique by comparing it with serum samples collected simultaneously by venous phlebotomy. Forty paired capillary- and venous samples were collected from 36 cardiac transplantation patients and analyzed, using a polyclonal immunoassay. The values obtained were compared using regression correlation. The correlation coefficient for all 40 samples was 0.859. However, we discovered that the first 7 capillary specimens were processed incorrectly. The correlation coefficient for the other 33 samples was 0.995 (99% confidence interval 0.987-0.998). The excellent correlation between serum samples obtained from capillary sampling and from venous sampling, together with the ease of obtaining capillary blood specimens, make "fingerstick" sampling the method of choice for monitoring cyclosporine levels in infants and children.

Nicotine nasal spray and nicotine gum have been found to be effective in relieving nicotine withdrawal symptoms. In this randomized single-blind study, 91 cigarette smokers were randomly assigned to a single 1 mg dose of active nicotine nasal spray (n=29), active 4 mg nicotine gum (n=31), saline placebo nasal spray (n=16) or placebo gum (n=15). Following overnight abstinence, subjects repeatedly completed visual analog scales for assessing nicotine withdrawal symptoms over 30 min preceding (time -30 min to time 0) and 120 min following a single dose of study medication. This sequence was performed 3 times during the day. Nicotine withdrawal symptoms were assessed on a 41-point visual analog scale (1=no withdrawal, 41=extreme withdrawal). At the initial session only, blood samples for serum nicotine levels were taken at baseline, then at 5, 10, 30 and 120 min following study drug administration. The mean (+/-SD) age of the subjects was 38.6 (+/-10.1) years, 48% were females, smoking rate was 24.5 (+/-7.8) cigarettes per day, and years of smoking was 19.9 (+/-10.0). A single 1 mg dose of nicotine nasal spray provided more immediate relief for craving for a cigarette compared to a single 4 mg dose of nicotine gum. Serum venous nicotine levels for the active nicotine nasal spray and nicotine gum were comparable at 5 and 10 min while the levels were higher for nicotine gum at 30 and 120 min. Changes in withdrawal symptoms were not found to be related to serum venous nicotine levels. Our findings provide a rationale for the as needed use of nicotine nasal spray to control withdrawal symptoms, possibly in combination with other medications with longer acting effects.

The silicone breast implant controversy rages on. Recent work has demonstrated that normal or baseline breast tissue silicon levels in women who had had no prior exposure to any type of breast implant may be as high as 446 microg/gm of tissue. These data ranged from 4 to 446 microg/gm of tissue, with a median of 27.0 microg/gm of tissue. In addition, numerous other epidemiologic and rheumatologic studies have demonstrated no association between silicone breast implants and any connective-tissue diseases. Despite these reports, the use of silicone implants remains restricted. The present study measured breast and capsular tissue silicon levels from 23 breasts in 14 patients with saline implants, and from 42 breasts in 29 patients with silicone implants. No patient in the saline implant group presented with signs or symptoms of connective-tissue disease. Patients with silicone implants, however, were divided into three groups based on the presence or absence of signs or symptoms of connective-tissue disease: group I, no symptoms or signs; group II, + symptoms, no signs; and group III, + symptoms, + signs. Six patients in group III were diagnosed with a specific connective-tissue disease, including systemic lupus erythematosus, rheumatoid arthritis, or scleroderma. The most common indications for implant removal or exchange were capsular contracture and implant rupture, although 41 percent of patients with silicone implants expressed media-related concern over the implant issue. The most common symptoms described by patients in groups II and III were joint pain and stiffness, arm pain and numbness, and fatigue. In all groups, capsular tissue silicon levels were significantly greater than breast tissue levels. This finding may indicate that the capsule serves as a barrier to the distribution of silicone from the implant into adjacent breast tissue. Although breast tissue silicon levels in patients with silicone implants were not significantly greater than those in patients with saline implants (p = 0.48), capsular tissue levels in patients with silicone implants were, indeed, significantly greater than those in patients with saline implants (p < 0.001). However, no statistically significant differences in tissue silicon levels were observed with relation to the presence or absence of connective-tissue disease signs or symptoms in patients with silicone implants (groups I to III). Therefore, these data strengthen the conclusion that there is no association between tissue silicon levels and connective-tissue disease.

Well-founded pharmacokinetic information is one of the cornerstones of a New Drug Application (NDA) to the Food and Drug Administration (FDA) required to introduce a new drug or a generic equivalent (ANDA) to the marketplace. The service that laboratories engaged in therapeutic drug monitoring provide to support clinical activities is also needed by the pharmaceutical industry during the evaluation and introduction of drugs to the marketplace. In considering this alternative service activity, one must be aware of and compliant with rules established by the FDA for performance of such studies. As specified in CFR 21, Parts 58, 211, and 320, good clinical and laboratory practice indicates that the laboratory should employ a Lab Study Director, who is responsible for the validation of all procedures implemented to support a study protocol, ensures that the laboratory carries out the study following these defined procedures, and personally reviews the results of all testing. The laboratory must validate each procedure by demonstrating and documenting that the procedure does what it is designed to do while meeting the analytical performance specifications required by the study. Laboratory records of all activities must be maintained and available for inspection by the FDA on request. The FDA has authority over all activities related to NDA and ANDA submissions and can bring criminal charges if results of a study are changed because a laboratory deviates from standard procedure. Competent drug monitoring laboratories are fully capable of participating in clinical trials testing activities. Laboratory staff should be fully versed in the FDA rules governing these activities, validate all procedures, and establish systems to verify the procedures are carried out as specified.

A method for analysis of silicon in tissue was developed to determine silicon content in breast parenchymal and periprosthetic capsular tissues of patients with silicone or saline implants and to compare levels in tissues from normal (nonaugmented) breasts. It is of interest to determine whether increased silicon content in tissues can be associated with morbidity in patients who have received silicone implants. This manuscript addresses the issues involved in analysis of breast tissue samples for silicon and compares silicon levels with tissue histologic findings and patient morbidity. One hundred sixty tissue samples were obtained for silicon analysis from 72 patients during augmentation, capsulectomy with or without replacement mammoplasty, mastectomy, or biopsy procedures and were frozen in acid-washed polystyrene tubes at 220 degrees C until analysis. Samples were thawed, sectioned to approximately 0.1 g (dry weight), and digested in nitric acid before analysis by inductively coupled plasma emission spectroscopy, monitoring emission intensity at 251.6 nm. Tissue silicon levels (breast parenchymal and periprosthetic capsular tissue) in patients with silicone gel implants were much higher (mean, 9,287 micrograms/g, n = 106) than in patients with saline implants (mean, 196 micrograms/g, n = 37) or nonaugmented breasts (mean, 64 micrograms/g, n = 17). Histologic examination was performed on 54 tissue samples stained with hematoxylin-eosin. Tissue samples were rated as to degree of inflammation and calcification, and amount of giant cells, foamy histiocytes, and vacuoles containing a colorless refractory material. Vacuolization and foamy histiocyte ratings correlated significantly with tissue silicon concentration. No correlations were found between tissue silicon concentration and inflammation, calcification, or giant cell rating. Implant age (number of years an implant was in place before sampling) correlated with capsular tissue silicon concentration in patients with intact implants but not in those with ruptured implants. No difference in tissue silicon concentration was found between patients with or without signs or symptoms of morbidity. Using 0.1 g of tissue, the method was linear to 1,000 micrograms/g, and sensitivity was 3.7 micrograms/g. Precision between runs (mean, 5.1 micrograms/g; coefficient of variance, 13.7%; n = 13) was calculated from multiple analyses of a bovine liver standard (National Bureau of Standards, reference material 1577a). Significant biologic variability (21.4% to 52.5%) was seen in tissues with high silicon levels. Paraffin-embedded, formalin-fixed tissues are not amenable to silicon analysis by this method, because of leaching of silicone from the tissues during preparation. Thus only fresh frozen tissue samples were used.

The ubiquitousness of silicon is well known. Recent work has demonstrated measurable baseline levels of silicon in nonaugmented cadavers, subsequent to numerous reports of significant elevations of such levels within patients with silicone breast implants and even more reports alleging a causal relation between silicone gel prostheses and connective-tissue diseases. Despite the lack of scientifically substantiated data that such a relation exists, the calamitous silicone breast implant controversy has ensued. Saline-filled breast implants are constructed with a silicone elastomer envelope that remains in direct contact with periprosthetic capsular tissue following implantation. Although there is no evidence to link saline implants with any disorders, it is important to know if saline breast implants contribute any silicon to human body baseline silicon levels. The present study measured tissue silicon levels in 28 breasts of 16 patients with saline-filled implants to determine if the silicone envelope of these prostheses can contribute to the elevation of such levels. These data were compared with data from 116 breasts of 65 patients with silicone gel-filled prostheses as well as breast tissue from 17 patients (controls) who had never been exposed to either type of implant. Samples of breast tissue and periprosthetic capsular tissue were obtained from patients with both intact and ruptured implants. Silicon levels of breast tissue specimens from patients with saline-filled implants were within the range of the controls if the implants were intact. Silicon levels in periprosthetic capsular tissue from patients with intact saline-filled implants were significantly higher than controls (p < 0.02); however, they were still 100-fold less than capsular tissue levels from patients with intact gel-filled implants. Silicon levels measured in both types of tissue were significantly elevated in patients with silicone gel-filled implants compared with controls (p < 0.01). In the case of ruptured gel implants, breast tissue demonstrated higher silicon levels than did similar specimens from patients with intact implants (p < 0.054); periprosthetic capsular tissue levels also were elevated, although the differences were not statistically significant (p = 0.54). These findings are independent of the implant brand or length of exposure to the particular prosthesis. The finding of elevated levels of silicon in both breast and periprosthetic capsular tissue in patients with silicone gel-filled implants in no way implies or substantiates any claim of a causal relationship between silicone and any reported illnesses.

Objective: To determine whether urinary magnesium (Mg) values in patients with gut failure would be more helpful than serum Mg measurements in assessment of Mg deficiency., Design: We compared serum and urinary Mg values in 16 patients with gut failure and 16 age- and sex-matched control subjects., Material and Methods: Sixteen patients with gut failure (nine women and seven men; mean age, 59 years) had serum and 24-hour urinary mg measured before Mg replacement therapy. Short bowel syndrome was present in 75%, and diffuse small bowel disease was present in 25%., Results: The median value for serum Mg was 1.7 mg/dL for patients and 2.0 mg/dL for healthy control subjects (P < 0.001). The median values for urinary Mg were 19 mg and 127 mg per 24-hour specimen in patient and control groups, respectively (P < 0.001). A strong correlation was noted between serum Mg and urinary Mg levels. All patients had low urinary Mg values even though 9 of 16 (56%) had normal serum Mg values. Two patients with normal serum Mg concentrations had urinary Mg values of 20 mg/24 h (25% of normal). Serum, but not urinary, Mg correlated significantly with the length of remaining small bowel (P = 0.03)., Conclusions: Urinary Mg declines before serum Mg and is an earlier and more reliable indicator of evolving Mg deficiency. On the basis of these observations and those showing beneficial effects of parenterally administered Mg supplements on urinary citrate excretion (and, presumably, formation of calcium oxalate stones), replacement of Mg in patients with gut failure should be targeted at normalizing urinary Mg.

A cold vapor atomic absorption technique for blood or urine mercury analysis that uses persulfate oxidation to prepare samples for total mercury analysis and acid permanganate oxidation to prepare samples for inorganic mercury analysis is described. The linearity of the procedures ranged from 0.5 to 25 micrograms/L. Precision ranged from 20% at 1 microgram/L to 7% at 20 micrograms/L. Documentation of accuracy is based on analysis of samples prepared by an international proficiency survey program. The development of a two-step digestion procedure followed by automated flow-injection mercury analysis was a necessary precursor to the assessment of inorganic and alkylmercury exposure in a large unexposed human population. Application of this technique to 902 blood and 902 urine samples collected from a normal human population who had no extraordinary mercury exposure generated mean plus two standard deviation skewed confidence-limit ranges of results as follows: blood total mercury, 0-8.4 micrograms/L; blood inorganic mercury, 0-1.7 micrograms/L; blood organic mercury, 0-7.5 micrograms/L; urine total mercury, 0-9.9 micrograms/L; urine inorganic mercury, 0-8.6 micrograms/L; and urine organic mercury, 0-1.8 micrograms/L.

Objective: There is a high prevalence of neurodegenerative disease (parkinsonism, dementia, and motor neuron disease) on the western Pacific island of Guam. We sought evidence in support of the hypothesis that these conditions are triggered by nutritional deficiencies of calcium and magnesium leading to secondary hyperparathyroidism that then facilitates the entry of calcium and toxic heavy metals into the brain., Methods: We analyzed indices of calcium metabolism plus blood-serum, urine, nail, and hair heavy metal concentrations in 12 patients with Guamanian neurodegenerative disease and 12 Chamorro control subjects., Results: All 12 patients with Guamanian neurodegenerative disease had normal values for serum total and ionized calcium, 25-hydroxyvitamin D, and 24-hour urine collections for calcium. Eleven of 12 patients had normal serum parathyroid hormone values and alkaline phosphatase levels. No patient had reduced serum phosphorus or magnesium values although a minority of patients and controls had low urinary magnesium concentrations. Median blood-serum and 24-hour urine collections for heavy metals (aluminum, arsenic, cadmium, copper, iron, lead, manganese, mercury, and zinc) were statistically similar in the patient and control groups except for a slight elevation of blood, but not urine, lead in the patient group. Concentrations of heavy metals in hair and nails were similar in the two groups., Conclusions: We could find no evidence in support of abnormalities of calcium metabolism or heavy metal absorption as a major causative factor in the development of neurodegenerative disease on the island of Guam.

Insulin influences both glucose metabolism and magnesium homeostasis in humans. The present studies sought to determine whether insulin-induced stimulation of magnesium uptake is impaired in noninsulin-dependent diabetes mellitus (NIDDM) and enhanced by acute hyperglycemia. To do so, we measured plasma magnesium concentrations in diabetic and nondiabetic subjects on two occasions: once when glucose concentrations were maintained constant and once when glucose concentrations were varied to mimic a postprandial pattern. The same amount of insulin was infused on both occasions in a manner that reproduced the systemic insulin concentrations normally observed after glucose ingestion. During the prandial insulin infusion, the decrement in the plasma magnesium concentration was lower (P < 0.05) in the diabetic patients than that in the nondiabetic subjects during both the euglycemic (4.1 +/- 0.9 vs. 7.8 +/- 1.3 mmol/L.4 h) and hyperglycemic (1.7 +/- 1.1 vs. 6.6 +/- 1.4 mmol/L.4 h) studies. Glucose disappearance also was lower (P < 0.05) in the diabetic patients than that in the nondiabetic subjects, and the insulin-induced decrement in plasma magnesium was correlated (P < 0.01) with glucose disappearance. On the other hand, despite higher (P < 0.05) rates of disappearance in the hyperglycemic than euglycemic experiments, the decrement in plasma magnesium did not differ in either group on either occasion. We conclude that insulin resistance in subjects with NIDDM impairs the ability of insulin to stimulate magnesium as well as glucose uptake.

The concentrations of five essential elements and six potentially toxic elements were determined in seven organs collected at autopsy from 30 human subjects. Elemental analyses were carried out by graphite furnace atomic absorption spectroscopy, and inductively coupled plasma emission spectroscopy, and inductively coupled plasma mass spectroscopy, and concentrations in fresh and formalin-fixed tissues were compared. Formalin-fixation long-term storage has little effect on most element concentrations in tissue, except for Al and Mn, which changed with prolonged storage in formalin. The kidney and liver contained the greatest concentrations of toxic elements compared with other organs, whereas the essential elements were uniformly distributed among all organs. There was no more than a 10-fold difference in the tissue concentration of the elements studied among the organs, except for the concentration of Fe in liver, and Ca and Mg in bone. We also demonstrate that these elements are homogeneously distributed in tissues.

The authors present a simple liver biopsy protocol that is a reliable and cost-effective method of diagnosing hepatic Wilson's disease. Biopsy specimens are obtained in routine fashion, without the need for copper-free solutions or instruments. The samples are then embedded in paraffin, stained for copper and copper-associated protein, and studied by light microscopy. Subsequently, a sample of hepatic parenchyma is excised from the paraffin block for chemical quantitation of tissue copper. This combination of methods generally yields reliable results and allows confirmation of the diagnosis in cases of Wilson's disease in which special stains for copper are negative. In most instances, electron-microscopic studies are not necessary.