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PubMed1988

Sweat tests in patients with diabetes insipidus.

Increased sweat chloride concentrations have been reported in patients with nephrogenic (NDI) but not central diabetes insipidus (CDI). To determine whether false-positive sweat tests also occur in CDI, six subjects with CDI had plasma electrolytes, osmolatities, and sweat tests performed before and after water deprivation. All subjects were hyperosmolar after dehydration (287 +/- 2.0 and 296 +/- 3.2 mosm/kg, plasma osmolality before and after dehydration, respectively; p = 0.02). Sweat chloride concentrations before and after dehydration were not different, and no positive sweat tests were observed. Sweat chloride concentrations after dehydration did not correlate with the degree of dehydration as assessed by either plasma sodium or plasma osmolality. We conclude that increased concentrations of chloride in sweat are not typically found in dehydrated subjects with CDI, although they have been reported in subjects with the nephrogenic form.

Adult↗

PubMed1991

Sweating threshold during isoflurane anesthesia in humans.

Isoflurane anesthesia in humans markedly decreases the threshold temperature triggering peripheral thermoregulatory vasoconstriction (i.e., central temperature triggering vasoconstriction). However, it is not known whether the sweating threshold remains unchanged (e.g., near 37 degrees C), decreases along with the vasoconstriction threshold, or increases during anesthetic administration. Accordingly, the hypothesis that isoflurane anesthesia increases the thermoregulatory threshold for sweating was tested. Forehead sweating was evaluated in five healthy patients given isoflurane anesthesia. The sweating threshold was prospectively defined as the distal esophageal temperature at which significant sweating was first observed. Sweating was observed in each patient at a mean central temperature of 38.3 +/- 0.3 degrees C and an end-tidal isoflurane concentration of 1.1% +/- 0.2%. The interthreshold range (difference between vasoconstriction and sweating thresholds) without anesthesia is approximately 0.5 degrees C; isoflurane anesthesia increases this range to approximately 4 degrees C.

Adult↗

PubMed2000

Micro-flowcell conductometric sweat analysis for cystic fibrosis diagnosis.

This paper describes a device specifically designed to facilitate neonatal sweat testing. The components are sized appropriately for attachment to the limbs of newborns. Iontophoretic electrodes, with pilocarpine gel inserts, are latched into small holders attached by straps to the limb. The holder at the anodic site remains in place to receive and align the sensor cell, which uses a conical collecting surface to channel the sweat directly and anaerobically from the sweat ducts to the continuous flow-through conductivity cell within its body. A crib-side analysis unit incorporates an iontophoretic power supply and displays a continuous readout of sweat electrical conductivity. The average conductivity during a specific time interval and the initial sweating rate are automatically displayed. The method, which simplifies sweat tests, is currently being assessed in three neonatal clinical trials to test its ability to reduce test failures in the newborn due to insufficient sweat.

Adult↗

PubMed2006

Opioid disposition in human sweat after controlled oral codeine administration.

BACKGROUND: Characterization of opioid excretion in sweat is important for accurate interpretation of sweat tests in drug treatment, criminal justice, and workplace drug testing programs. METHODS: Participants (n=20) received placebo, 3 low (60 mg/70 kg) or 3 high (120 mg/70 kg) codeine sulfate doses (used as a model for opioid excretion) within 1 week. Codeine and metabolites in sweat were collected with PharmChek Sweat Patches; hourly patches were applied for 1 to 15 h (n=775) and weekly patches for 7 days (n=118). Patches were analyzed by solid-phase extraction and gas chromatography-mass spectrometry for codeine, norcodeine, morphine, normorphine, and 6-acetylmorphine. Limits of quantification were 2.5 ng/patch (codeine and morphine) and 5 ng/patch (other analytes). RESULTS: Codeine was the only analyte identified in 12.6% of hourly patches and 83.3% of weekly sweat patches worn during dosing. Weekly patch concentrations (SD) were 38.6 (59.9) ng/patch [median (range), 15.9 (0-225.1) ng/patch] for low and 34.1 (32.7) ng/patch [24.0 (0-96.2) ng/patch] for high codeine doses. Codeine detected 1 week after dosing was 4.6 (5.3) ng/patch [median (range), 4.0 (0-17.1) ng/patch; n=11] after low and 7.7 (7.1) ng/patch [6.9 (0-20.5) ng/patch; n=10] after high doses. In total, 2.6% of hourly, 38.5% of low-dose, and 45.5% of high-dose weekly patches contained codeine at the proposed Substance Abuse and Mental Health Services Administration cutoff. CONCLUSIONS: Codeine was the only analyte detected, at highly variable concentrations, up to 2 weeks after dosing. These results are consistent, considering the complex processes of codeine deposition in sweat. Sweat testing is a useful alternative technique for qualitative monitoring of opioid use.

Administration, Oral↗

PubMed2001

Concentrations of trace elements in sweat during sauna bathing.

Trace elements in sweat during sauna bathing were assessed. Sweat collected by the whole body method was compared with that collected by the arm bag method. The sweat samples were collected from ten healthy male adults aged 22-26 years, by heat exposure in dry sauna bathing (60 degrees C, 30 minutes). Concentrations of major (Na, Cl, K, Ca, P and Mg) and trace (Zn, Cu, Fe, Ni, Cr and Mn) elements in sweat tended to be lower in the arm bag method than in the whole body method. It was found that Ca, Mg, Fe and Mn concentrations in the arm bag method were significantly lower than those in the whole body method. The amount of trace elements in sweat measured by the arm bag method was less than that by the whole body method; significant differences were observed in Fe and Mn amounts. These observations suggest that excretion of trace elements by sweating induces trace element decrease. Therefore, athletes and workers who work in a hot environment and sweat much habitually should ingest adequate amounts of trace elements.

Adult↗

PubMed1991

[Functional differentiation of thermoregulation, with particular references to seasonal variation of whole body sweat rate of exercising man].

We investigated the seasonal variation of sweating response during exercise. Four adult healthy men repeated a moderate bicycle exercise (60 watts) in a climatic chamber of an ambient temperature of 30 degrees C (relative humidity, 45%) in winter, spring, summer, and fall. In summer, sweat rate immediately increased as soon as the exercise started, whereas in winter in a few minutes. The mean sweat rate during exercise was significantly different between winter and summer. The transient reduction of the Tsk was observed at the beginning of the exercise in winter. The Tsk decreased in proportion to increasing of sweat rate in each season. Significantly negative correlations were found between sweat rate and the rate of change of Tsk during exercise in each season. The slope and intercept of regression line were significantly different between winter and summer. The index of sweating was made available for the relative value, changing rate against annual mean value of total sweat loss (delta SR, %). The relative value rather than the absolute value (i.e., expressed as g.m-2.h-1) corrected well with skin temperature. It is suggested that the present results may reflect adapted changes in the thermoregulatory mechanisms to seasonal acclimatization. Moreover, the fall in skin temperature during exercise may be not due to increased evaporative cooling, but may be the result of vasoconstriction probably caused by non-thermal factors.

Acclimatization↗

PubMed1988

Borderline sweat test: criteria for cystic fibrosis diagnosis.

The CF diagnosis can be difficult in subjects with disease consistent symptoms and borderline values of the sweat test. This study aimed to evaluate possibly resolutory criteria. Seventy-one ill subjects with borderline sweat test values (40-70 mEq/l Cl-) aged 0.1-37.7 years (mean, 8.7; SD, 7.3) were studied and compared with 33 age-matched CF patients (Cl- over 75 mEq/l) and 25 healthy subjects. A complex CF score based on 25 variables was set: CF-specific clinical conditions, detailed analysis of sweat test (salt-free diet test included), pancreatic function, Pseudomonas infection, and others. The score ranged from 0 to a maximum of 65 and clearly distinguished the CF patients from the healthy subjects. Therefore the CF score was assumed as the best reference criterion to define the diagnosis in the borderline group: 27 of them (38%) were assigned to the CF condition and 44 (62%) to the healthy one, with a quite clear separation between the 2 subgroups. With respect to these assignments, the most discriminant variable turned out to be the sweat Cl- persisting above 40 mEq/l after 5 days of salt-free diet (mean error, 18.4%). Neither sweat Cl-/Na+ ratio nor bicarbonate duodenal output showed better discriminant power (mean error, 29% and 25%, respectively). It is concluded that in borderline situations of sweat test results a definite CF diagnosis can be achieved only by compounding many clinical and laboratory data with a preference for the sweat test after a salt-free diet period. The CF score proposal can be an effective help.

Adult↗

PubMed2001

Effect of simulated microgravity exposure on thermoregulatory control of sweating.

The purpose of the present study was to investigate the alterations in thermoregulatory control following 14 days of head-down bed rest (HDBR). The threshold temperature for sweating onset and sweating sensitivity were determined from sweating rates on the chest and forearm, and tympanic temperature as an index of core temperature (Tc) in nine healthy males exposed to a 60-min heat stress with a water-perfused blanket before and after HDBR. The threshold temperature for sweating onset, that is, the Tc at which sweating began on the chest and forearm was 36.75 +/- 0.14 and 36.72 +/- 0.13 degrees C before HDBR, respectively. The value significantly increased to 37.05 +/- 0.09 (p<0.05) for the chest and 37.04 +/- 0.08 degrees C (p<0.05) for the forearm after HDBR. On the other hand, the sweating sensitivity which was indicated as a slope of the Tc-sweating rate relationship significantly decreased from 4.20 +/- 1.15 to 2.32 +/- 1.18 for the chest (p<0.05) and from 4.20 +/- 1.06 to 2.92 +/- 0.98 mg/min/cm2/degrees C for the forearm (p<0.05) after HDBR. These findings suggest that the heat-dissipatory function was attenuated after 14 days of HDBR.

Adult↗

PubMed1992

[Effect of thermal dehydration on blood levels of hormones regulating volume and electrolyte content of sweat in patients with kidney transplantation].

The thermal dehydration test was performed in 12 patients with renal transplant and in 20 healthy subjects. The study was aimed at the evaluation of the effect of volume regulating hormones on electrolyte composition of thermal sweat in patients with renal transplant. Blood plasma renin activity (PRA) as well as plasma concentrations of aldosterone (ALD), vasopressin (AVP) and atrial natriuretic peptide (ANP) were determined before and after thermal dehydration in all the subjects studied. In all the subjects sweat was also collected after 15 and 45 minutes of exposition to heat and the concentrations of sodium, potassium and chloride were determined in all sweat samples. Significantly elevated PRA and ANP concentrations and significantly lowered plasma AVP concentrations but normal ALD levels were found before thermal dehydration test in all the patients with renal transplant. After the exposition to heat lasting 1 hour the direction of changes was similar, their magnitude was, however, different in renal transplant patients than in healthy subjects. In addition, lower concentrations of sodium and chloride in thermal sweat and lower total concentration of sweat solids were found in renal transplant patients than in healthy controls. No significant correlation was found between the plasma concentrations of the hormones determined and the electrolyte concentrations of thermal sweat both in the renal transplant patients and in healthy subjects. The results suggest that the volume regulating hormones have no effect on the electrolyte composition of thermal sweat induced by short exposition to heat both in renal transplant patients and in healthy subjects.

Adult↗

PubMed1988

Biochemical changes in sweat following prolonged ischemia.

Much emphasis has been placed on the measurement of physical parameters at the body support interface in order to detect and moderate conditions which could result in pressure damage to soft tissues. Major difficulties are encountered both in the design of instrumentation and interpretation of the data collected. Metabolic processes in sweat glands that control sweat secretion have been shown to be sensitive to applied pressure, producing sweating rate suppression and changes in sweat NaCl concentration. In this study, we have demonstrated the feasibility of measuring lactate concentration in sweat collected locally using an electrochemical stimulation technique (iontophoresis of pilocarpine nitrate). Elevated levels of sweat lactate concentration during local tissue indentation were detected in a group of able-bodied subjects. Upon removal of the indentor, however, levels of sweat lactate returned to normal.

Adult↗

PubMed1986

Evaluation of a cystic fibrosis screening system incorporating a miniature sweat stimulator and disposable chloride sensor.

A new sweat test (CF Indicator; Medtronic, Inc.) for cystic fibrosis (CF) features a compact, portable configuration of electrodes that dispense pilocarpine for iontophoresis. A disposable chloride sensor patch absorbs a specified volume of sweat, in which the chloride concentration is immediately determined as less than 40, 40-60, or greater than 60 mmol/L. We assessed the performance of the system in a five-center study, in relation to the clinical diagnosis and to the Gibson-Cooke sweat test (GCST) as a control test. With sweat chloride concentrations of less than or equal to 40 mmol/L defined as normal and greater than 40 mmol/L as indicating persons at risk for CF, the new system showed 91% specificity and 100% sensitivity for CF, as compared with 92.8% and 100%, respectively, for the GCST. When we used sweat chloride concentrations of less than or equal to 60 mmol/L as probably normal and greater than 60 mmol/L as probably indicative of CF, the new system showed a 99.1% specificity and 98.6% sensitivity, vs 97.8% specificity and 97.9% sensitivity for the GCST test. In both procedures, occasionally insufficient sweat was collected, and this appeared related to the age of the subject. We conclude that the new sweat test system is potentially useful in physicians' offices, in clinics, and similar settings.

Adolescent↗

PubMed1993

Disappearance of seasonal variation of sweating responses in exercising man: effect of pre-heating in cold season.

The present study was designed to investigate the seasonal variation in thermal responses during moderate exercise. In winter, exercise was done after pre-heating for 30 min at an ambient temperature of 30 degrees C. Adult healthy men repeated the exercise at 40% of maximal oxygen uptake by a bicycle ergometer in a climatic chamber of an ambient temperature of 30 degrees C (relative humidity, 45%) in winter, spring, summer, and fall. In summer, the sweat rate increased immediately after the exercise started, whereas in winter it took in several minutes. The average sweat rate during exercise was significantly different (p < 0.01) in winter and compared to the other seasons. Significantly (p < 0.01) negative correlations were found between sweat rate and the rate of change of the mean skin temperature in each season. The regression equation was significantly (p < 0.01) different between winter and summer. After the pre-heating in winter, the sweating responses during exercise were similar to the responses in the summer. Thus, by thermal stimuli, the heat dissipation, especially skin evaporation due to sweating, may be stimulated in the cold season. It is suggested that sweating may be facilitated by not only the heat dissipation capacity of the hypothalamic mechanism with the thermal information via skin thermoreceptors but also by a change of peripheral sweat gland activity. Furthermore, the fall in skin temperature during the initial exercise may not be due to increased evaporative cooling, but to the vasoconstriction probably caused by non-thermal factors.

Acclimatization↗

PubMed1994

Current status of sweat testing in North America. Results of the College of American Pathologists needs assessment survey.

The College of American Pathologists surveyed 5096 laboratories for information concerning collection and analytic methodologies used in the performance of the sweat test. The test measures the concentration of electrolytes in sweat and is an essential criterion for the diagnosis of cystic fibrosis. An 83% response rate was achieved on the needs assessment survey, representing the first large-scale, national study of sweat testing practices. Nineteen percent of the respondents perform sweat testing in their laboratory, and the majority of the respondents analyze the sweat for chloride concentration. Fifty-nine percent of the laboratories performing sweat testing indicated an interest in participating in proficiency testing for sweat analysis. The information gathered from the needs assessment survey will be used to develop a comprehensive proficiency testing program to provide feedback and education to laboratories performing this critical diagnostic test.

Chemistry, Clinical↗

PubMed1996

A new individualization marker of sweat: deoxyribonuclease I (DNase I) polymorphism.

We confirmed for the first time, both biochemically and immunologically, the existence of deoxyribonuclease I (DNase I) in human liquid sweat. Isoelectric focusing of sweat samples on polyacrylamide gels (pH 3.5 to 5), followed by dried agarose film overlay detection, was used to determine the phenotypes of sweat DNase I. Because this detection method not only had high sensitivity, but also high band resolution, it was possible to determine DNase I types from sweat samples of 50 to 100 microL. Pretreatment of sweat samples with sialidase was essential for typing to enhance markedly the sensitivity accompanied by simplification of the isozyme pattern. The DNase I types in all sweat samples were consistently related to the types found in corresponding blood, urine, and semen samples. DNase I typing could, therefore, provide a novel discriminant characteristic in the forensic examination of sweat.

Biomarkers↗

PubMed1997

Descriptive epidemiology of sweating in a hospice population.

Sweating can be a distressing and difficult problem to manage in patients with advanced cancer. Despite this, new published data exist on the frequency, nature, and severity of sweating in cancer patients. This prospective survey describes the epidemiology of sweating in patients with advanced cancer on admission to a London hospice. 153 consecutive admissions were assessed. Of these, 100 were suitable for inclusion into the study. A general symptom enquiry was performed on all patients. Age, sex, primary diagnoses, extent of diseases, relevant secondary diagnoses, and concurrent medication were also recorded. 16 patients volunteered sweating as a problem. For 12 of these 16 patients, sweating had been severe (drenching sweats requiring change of clothing or bedlinen or both) in nature. This survey highlights sweating as a significant problem in this group of patients.

Adult↗

PubMed1996

The sweat of patients with atopic dermatitis contains specific IgE antibodies to inhalant allergens.

We have investigated levels of total and specific IgE against inhalant allergens in the sweat of 15 patients with atopic dermatitis, 10 patients with allergic rhinitis and high levels of specific IgE in the serum, and five patients with psoriasis without atopy as controls, by means of various commercial methods such as fluorescence immunoassay, nephelometry, chemiluminescence assay, enzyme immunoassay and the radioallergosorbent test. Total IgE and specific IgE antibodies were detectable in the sweat of patients with atopic dermatitis as well as of patients with allergic rhinitis alone. These levels of total IgE in the sweat correlated with the severity of the skin disease (P < 0.05). By means of the Ciba Corning assay (P < 0.001), the fluorescence immunoassay (P < 0.05) and the nephelometry assay (P < 0.05), positive correlations were then established between the levels of total IgE in the serum and the sweat. Moreover, specific IgE antibodies to birch pollen and Dermatophagoides pteronyssinus were detectable in the sweat and correlated positively with these specific IgE levels in the serum (P < 0.05). Further, the specific IgE levels against these allergens in the sweat also correlated with the severity of dermatitis (P < 0.05). It is suggested that these specific IgE antibodies against certain inhalant allergens in the sweat of patients with atopic dermatitis may play a role in allergen trapping in the skin.

Adolescent↗

PubMed1997

Predicting changes in the distribution of sweating following thoracoscopic sympathectomy.

BACKGROUND: Compensatory sweating is a common symptom following thoracic sympathectomy; however, the reported incidence of this complication varies greatly, and its severity has not been quantified. METHODS: In this study changes in the distribution of sweating following bilateral T2-3 thoracoscopic sympathectomy for hyperhidrosis were assessed in 42 patients. Sweat production in the palms, axillae, face, trunk and feet was assessed using a linear analogue scale. RESULTS: The operation was most successful in reducing sweat production in the palms, axillae and face (in descending order). The operation also reduced pedal sweat production in 12 of the 29 patients who suffered concomitant pedal hyperhidrosis. Compensatory truncal sweating occurred in 36 of the 42 patients; it was severe in ten, moderate in 16 and minimal in ten. CONCLUSION: Patients should be warned about compensatory sweating before thoracic sympathectomy.

Adult↗

PubMed1994

Sweat function in Parkinson's disease.

Sweat function was studied in patients with Parkinson's disease and in normal adults by sympathetic skin response, the bromphenol blue printing method and the silicone mould method. In patients with Parkinson's disease, dysfunction of sweating was classified into two types: one type involved the postganglionic fibres and the other involved the preganglionic fibres or the central nervous system. The latter was observed in patients with milder disease and the former was observed in patients with severe disease. The progressive involvement of sweat function in Parkinson's disease may reflect spread from the central nervous system or preganglionic fibres to postganglionic fibres. In a few patients the results of sweat tests were normal. Ceruletide increased sweating in Parkinson's disease patients, and decreased the prolonged latency of the sympathetic skin response. It is hypothesized that ceruletide facilitates the preserved somatosympathetic reflex of sweating.

Aged↗