Sweat ethanol concentrations are highly correlated with co-existing blood values in humans.
This study compared the concentration of ethanol, both absolute and relative to water content, in sweat and blood. Ten male volunteers consumed approximately 13 mmol (kg body weight)-1 of ethanol. Blood and sweat samples were collected approximately 1, 2 and 3 h following ingestion. Sweat was collected following pilocarpine iontophoresis using an anaerobic technique that prevented ethanol evaporation. In addition, the water content of sweat and blood samples was determined. The correlation between sweat and blood ethanol, expressed in mmol l-1, was r = 0.98. The slope of the relationship was 0.81. When corrected for the water content in each sample, and expressed as mmoles per litre of water, the correlation remained very high (r = 0.97) while the slope increased to 1.01. These results suggest that rapid and complete equilibrium of ethanol occurs across the sweat gland epithelium. (+info)
Increased frequency of cystic fibrosis deltaF508 mutation in bronchiectasis associated with rheumatoid arthritis.
This study investigated the clinical characteristics and the possible involvement of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in patients with symptomatic diffuse bronchiectasis (DB) associated with rheumatoid arthritis (RA). Twenty-six patients with both RA and DB (group RA+DB) and control groups of 29 consecutive patients with RA but no bronchiectasis (group RA) and 29 patients with symptomatic DB of unknown origin (group DB) were prospectively studied. Among the patients of the RA+DB group, four (15.4%) were heterozygous for the CFTR gene deltaF508 mutation, whereas no deltaF508 mutation was found in patients of the RA and the DB groups (both, p<0.05). This frequency of deltaF508 mutation was also higher than the expected frequency (2.8%) in the general European population (p<0.04). Sweat chloride values and nasal potential differences were normal in three out of four patients carrying the deltaF508 mutation. In the RA+DB group, those with deltaF508 mutation had more frequent chronic sinusitis (p<0.05), a trend toward a more severe pulmonary involvement, and a lower value of nasal potential differences (p<0.01) whereas their rheumatic features had no particularity. In the RA+DB group, patients with adult-onset bronchiectasis (including two with deltaF508 mutation) had a greater reduction in total lung capacity (p<0.05) and lower nasal potential differences (p<0.005) than those with childhood-onset bronchiectasis. This study suggests a possible deleterious effect of the cystic fibrosis transmembrane conductance regulator mutated protein in the airways which may predispose to the development and severity of bronchiectasis in patients suffering from rheumatoid arthritis. (+info)
A collection method and high-sensitivity enzyme immunoassay for sweat pyridinoline and deoxypyridinoline cross-links.
BACKGROUND: Collagen cross-link molecules such as pyridinoline (PYD), deoxypyridinoline (DPD), and N-terminal cross-linked peptides (NTX) have been measured in urine as indices of bone resorption. However, very little is known regarding the excretion of pyridinolines into other biological fluids. We report a collection device, normalizing analyte, and high-sensitivity immunoassay for quantitative analysis of free pyridinoline cross-links in sweat. METHODS: Flame atomic emission and ion-selective electrode techniques were used to measure potassium as a sweat volume marker. The Pyrilinks immunoassay for urine free pyridinolines was optimized to increase sensitivity for measurements in sweat. The precision, accuracy, and detection limit of this assay were characterized. To assess values and variability of sweat pyridinolines in human subjects, a nonocclusive skin patch was used to collect sweat samples from a reference group and from a mixed group experiencing accelerated bone resorption, postmenopausal women and men receiving gonadotropin-releasing hormone for prostate cancer. RESULTS: The immunoassay intra- and interassay variations were +info)
Monitoring cocaine use in substance-abuse-treatment patients by sweat and urine testing.
Sweat and urine specimens were collected from 44 methadone-maintenance patients to evaluate the use of sweat testing to monitor cocaine use. Paired sweat patches that were applied and removed weekly (on Tuesdays) were compared with 3-5 consecutive urine specimens collected Mondays, Wednesdays, and Fridays. All patches (N = 930) were extracted in 2.5 mL of solvent and analyzed by ELISA immunoassay (cutoff concentration 10 ng/mL); a subset of patches (N = 591) was also analyzed by gas chromatography-mass spectrometry (GC-MS) for cocaine, benzoylecgonine (BZE), and ecgonine methyl ester (EME) (cutoff concentration 5 ng/mL). Urine specimens were subjected to qualitative analysis by EMIT (cutoff 300 ng/mL) and subsets were analyzed by TDx (semiquantitative, LOD 30 ng/mL) and by GC-MS for cocaine (LOD 5 ng/mL). Results were evaluated to (1) determine the relative amounts of cocaine and its metabolites in sweat; (2) assess replicability in duplicate patches; (3) compare ELISA and GC-MS results for cocaine in sweat; and (4) compare the detection of cocaine use by sweat and urine testing. Cocaine was detected by GC-MS in 99% of ELISA-positive sweat patches; median concentrations of cocaine, BZE, and EME were 378, 78.7, and 74 ng/mL, respectively. Agreement in duplicate patches was approximately 90% by ELISA analysis. The sensitivity, specificity, and efficiency of sweat ELISA cocaine results as compared with sweat GC-MS results were 93.6%, 91.3%, and 93.2%, respectively. The sensitivity, specificity, and efficiency between ELISA sweat patch and EMIT urine results were 97.6%, 60.5%, and 77.7%, respectively. These results support the use of sweat patches for monitoring cocaine use, though further evaluation is needed. (+info)
Drug testing with alternative matrices II. Mechanisms of cocaine and codeine deposition in hair.
A 10-week inpatient study was performed to evaluate cocaine, codeine, and metabolite disposition in biological matrices collected from volunteers. An initial report described drug disposition in plasma, sebum, and stratum corneum collected from five African-American males. This report focuses on drug disposition in hair and sweat collected from the same five subjects. Following a three-week washout period, three doses of cocaine HCl (75 mg/70 kg, subcutaneous) and three doses of codeine SO4 (60 mg/70 kg, oral) were administered on alternating days in week 4 (low-dose week). The same dosing sequence was repeated in week 8 with doubled doses (high-dose week). Hair was collected by shaving the entire scalp once each week. Hair from the anterior vertex was divided into two portions. One portion was washed with isopropanol and phosphate buffer; the other portion was not washed. Hair was enzymatically digested, samples were centrifuged, and the supernatant was collected. Sweat was collected periodically by placing PharmChek sweat patches on the torso. Drugs were extracted from sweat patches with methanol/0.2 M sodium acetate buffer (75:25, v/v). Supernatants from hair digests, hair washes, and sweat patch extracts were processed by solid-phase extraction followed by gas chromatography-mass spectrometry analysis for cocaine, codeine, 6-acetylmorphine, and metabolites. Cocaine and codeine were the primary analytes identified in sweat patches and hair. Drugs were detected in sweat within 8 h after dosing, and drug secretion primarily occurred within 24 h after dosing. No clear relationship was observed between dose and drug concentrations in sweat. Drug incorporation into hair appeared to be dose-dependent. Drugs were detected in hair within 1-3 days after the last drug administration; peak drug concentrations generally occurred in the following 1-2 weeks; thereafter, drug concentrations decreased. Solvent washes removed 50-55% of cocaine and codeine from hair collected 1-3 days after the last drug dose. These data may reflect removal of drug that was deposited by sweat shortly after dosing. Drug removed by washing hair collected 1-3 weeks after the last dose was minimal for cocaine but variable for codeine. Drug in these specimens was likely transferred from blood to germinative hair cells followed by emergence of drug in growing hair. These findings suggest that drug deposition in hair occurs by multiple mechanisms. (+info)
Equine sweating responses to submaximal exercise during 21 days of heat acclimation.
This study examined sweating responses in six exercise-trained horses during 21 consecutive days (4 h/day) of exposure to, and daily exercise in, hot humid conditions (32-34 degrees C, 80-85% relative humidity). On days 0, 3, 7, 14, and 21, horses completed a standardized exercise test on a treadmill (6 degrees incline) at a speed eliciting 50% of maximal O(2) uptake until a pulmonary artery temperature of 41.5 degrees C was attained. Sweat was collected at rest, every 5 min during exercise, and during 1 h of standing recovery for measurement of ion composition (Na(+), K(+), and Cl(-)) and sweating rate (SR). There was no change in the mean time to reach a pulmonary artery temperature of 41.5 degrees C (range 19.09 +/- 1.41 min on day 0 to 20.92 +/- 1.98 min on day 3). Peak SR during exercise (ml. m(-2). min(-1)) increased on day 7 (57.5 +/- 5. 0) but was not different on day 21 (48.0 +/- 4.7) compared with day 0 (52.0 +/- 3.4). Heat acclimation resulted in a 17% decline in SR during recovery and decreases in body mass and sweat fluid losses during the standardized exercise test of 25 and 22%, respectively, by day 21. By day 21, there was also a 10% decrease in mean sweat Na(+) concentration for a given SR during exercise and recovery; this contributed to an approximately 26% decrease in calculated total sweat ion losses (3,112 +/- 114 mmol on day 0 vs. 2,295 +/- 107 mmol on day 21). By day 21, there was a decrease in sweating threshold ( approximately 1 degrees C) but no change in sweat sensitivity. It is concluded that horses responded to 21 days of acclimation to, and exercise in, hot humid conditions with a reduction in sweat ion losses attributed to decreases in sweat Na(+) concentration and SR during recovery. (+info)
Indirect measurements of sweat electrolyte concentration in the laboratory diagnosis of cystic fibrosis.
AIM: To investigate whether analytical methods based on the colligative physical chemical properties of ions or solutes in sweat are less effective than the specific measurement of electrolytes in the diagnosis of cystic fibrosis (CF). METHODS: A single sweat sample was collected (Macroduct) from each of 211 infants and children, of whom 57 had CF, for the measurement of sodium, chloride, osmolality, and conductivity. RESULTS: The ranges within which CF and non-CF individual values overlapped (equivocal ranges), were wider for sodium and osmolality measurement than for chloride or conductivity. Neither of the latter two measurements provided a discriminatory advantage over the other. The utilisation of broadly based age related ranges for non-CF control subjects served to improve the discriminatory power of all four measurements to an extent that, in this cohort, both chloride and conductivity provided complete discrimination. CONCLUSION: Sweat conductivity is as effective as chloride measurement in the laboratory diagnosis of CF. (+info)
Inconsistencies in sweat testing in UK laboratories.
BACKGROUND: Sweat testing procedures are perceived to vary widely. AIM: To evaluate variability in sweat collection, analysis, and interpretation. METHODS: Questionnaire responses from 30 self selected centres: 15 paediatric centres, and 15 district general hospitals. RESULTS: Centres carried out 30-400 tests per year (median 100), with a diagnostic rate of 1:5-152 (median 1:30). Staff performed 5-268 tests per year. Minimum test age varied from 24 hours to four months. All stimulated sweating by pilocarpine iontophoresis using varying currents and times. Twenty six had observed urticaria or skin reddening, and nine blistering or burns. Sweat was collected for 10-60 minutes onto filter paper or into Macroduct coils. Between 2% and 25% of tests were considered insufficient. Twenty eight measured sodium, 24 chloride, and one osmolality and conductivity. Fifteen used literature and five in house reference ranges. Eleven would not test severely eczematous children. CONCLUSIONS: Local audit is required to improve performance, as well as a national guideline to standardise collection, and external quality assessment to provide analytical feedback. (+info)