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At least 919 records · Page 51Linked to original sources

PubMed1979

Negative effects of oral fatty acid supplementation on sweat chloride in cystic fibrosis.

Essential fatty acid supplementation with oral safflower oil (1 gm/kg/day) to 11 cystic fibrosis patients (aged 6 months to 14 years) for one year produced no significant change in sweat chloride concentration (mEq/liter) or sweat rate (gm/min/m2), Addition of vitamin E (10 mg/kg/day) to the safflower oil had no effect on sweat chloride concentration or rate compared to placebo. No clinical improvement could be detected compared to a control group. These results do not support previous reports of the effects of fatty acid supplementation on sweat electrolyte concentrations in cystic fibrosis.

Adolescent↗

PubMed1983

A puzzling triad: anorexia nervosa, high sweat electrolytes and indication to partial exocrine pancreatic insufficiency.

This report describes a 15-year-old girl with anorexia nervosa whose sweat electrolytes and pancreatic exocrine function were abnormal during a state of malnutrition. Both findings normalized when nutrition improved. The patient did not have any evidence of disorders known to be associated with an abnormal sweat test, including most importantly cystic fibrosis. It is postulated that the elevated sweat electrolytes and the pancreatic insufficiency developed in this patient secondary to malnutrition. The pathophysiological mechanism for both phenomena remains obscure. It is recommended that positive sweat tests in malnourished children should be repeated several times in a corrected nutritional state in order to obviate an erroneous diagnosis of cystic fibrosis.

4-Aminobenzoic Acid↗

PubMed1984

Tubulocisternal endoplasmic reticulum in human eccrine sweat glands.

Human eccrine sweat glands, including those expressing the gene for cystic fibrosis, were stained sequentially en bloc with uranyl acetate, lead citrate and copper sulfate, and osmium tetroxide for the ultrastructural demonstration of tubulocisternal endoplasmic reticulum (TER). This organelle has been associated with water and electrolyte transport in other epithelia. TER was present in the apical cytoplasm and basolateral cytoplasm circumscribing intercellular canaliculi of clear cells in the secretory coil and in the apical cuticular cytoplasm of luminal cells in the coiled duct. In both the secretory coil and duct, TER was situated strategically around the tight junctions. Together, the TER and tight junctions may regulate the secretory and absorptive permeability of the eccrine sweat gland to NaCl and water. The dark cell of the coil which is exocrine, and the deep cell of the duct which lacked tight junctions, did not contain TER. In sweat glands obtained from three cases of cystic fibrosis, elements of TER were more prevalent and complex in luminal cells of the secretory duct than was the TER in normal sweat glands. This difference may be a consequence of the basic electrolyte abnormality of cystic fibrosis.

Cystic Fibrosis↗

PubMed1983

100% oxygen breathing during acute heat stress: effect on sweat composition.

Twelve male Indian Air Force subjects were exposed on two occasions to a simulated hot environment (DB 57 degrees C; WB 35.5 degrees C; RH 25%) for a period of 50 min. On one occasion the subject breathed normal atmospheric air while on the other occasion he breathed 100% oxygen at ambient atmospheric pressure. Arm sweat collected at the end of the two experiments was analysed for Na+, K+, Mg++, C1-, and lactic acid. Arm sweat Mg++ was found to be much higher than that reported in the literature. Hyperoxia during heat stress improved arm sweating and showed significantly lower concentrations of Mg++, Na+, K+, and lactic acid. However, the total loss of these cations and lactic acid through the arm were not found to differ significantly for the two experiments. Based on arm sweat concentration, when the total body loss of these cations was worked out for the two runs, only whole-body Mg++ showed a significantly lesser loss during hyperoxia. The selective retention of Mg++ during the hyperoxic heat run and its association in lowering the heat-induced physiological strain are discussed.

Adult↗

PubMed1983

Freeze fracture morphology of the tight junctions of the eccrine sweat gland from patients with cystic fibrosis.

The resorption of Na+ and Cl- across the duct of the human eccrine sweat gland is markedly decreased in individuals with cystic fibrosis (CF). Conceivably, a defective transcellular ion transport mechanism or an increased paracellular backflux of ions could account for the abnormal salt resorption in the sweat gland duct and other organs affected in CF. Tight junctions are thought to regulate paracellular ion flow. Specifically, the number of junctional elements observed by freeze fracture are believed to correspond with the extent of paracellular transport. We compared the freeze fracture morphology of tight junctions of eccrine sweat glands taken from 11 control and seven CF patients. In an attempt to "fingerprint" the junctions morphometrically, the following parameters were measured: the number of strands, the depth of the junction from the apical to the basal strand, the angle of intersection between strands, and the mean distance along a strand between intersections with two other strands. No significant difference was observed between control and CF sweat glands in the freeze fracture morphology of the tight junctions of the duct, the segment where the net reabsorption of Na+ and Cl- is abnormally decreased in CF. Significant changes were observed, however, in the means of the number of strands, the depth, and the distance between intersections for the tight junctions of the intercellular canaliculus of the secretory coil, which appears to function normally in CF.

Adolescent↗

PubMed1994

Innervation and vasculature of human sweat glands: an immunohistochemistry-laser scanning confocal fluorescence microscopy study.

Secreting tubules, nerves fibers, and blood vessels in human sweat glands (SGs) were fluorescently stained by immunohistochemical and lectin methods for examination with a laser scanning confocal microscope (LSCM). Using these techniques, the three-dimensional distribution of up to three substances within a single specimen was investigated by collecting a series of optical sections for each of three fluorophores. Each SG received several nerve fibers. These branched into delicate bands of one or more axons that ran longitudinal to the sweat tubule then encircled the tubule. A heavy complement of capillaries was interwoven among the sweat tubules. Sweat ducts were accompanied from the SG toward the skin surface by one or two longitudinally oriented nerve fibers and capillaries. Immunoreactive staining of nerves was heaviest with protein gene product 9.5 antibody, but triple labeling showed that immunoreactivity to calcitonin gene-related peptide, vasoactive intestinal polypeptide, and synaptophysin was also present in the same axons. Substance P-immunoreactive axons were sparse in SGs but were present in other areas of the skin. The techniques used have considerable potential in examination of human skin biopsies for diagnosis of disorders affecting the somatic and autonomic nervous systems.

Adolescent↗

PubMedDate not supplied

The extractability of Cr(VI) from contaminated soil in synthetic sweat.

Hexavalent chromium is a common skin irritant that can cause contact dermatitis in sensitized individuals. Soil samples from two chromium waste sites having different Cr(VI) concentrations were extracted in synthetic sweat solutions over a pH range of 4 to 8 and analyzed for Cr(VI). These extractions were performed to determine the potential availability of Cr(VI) from contaminated soils upon contact with human sweat. The samples were also extracted using the EPA Method 3060 alkaline digestion. Overall, hexavalent chromium was readily extractable from both samples in the solutions tested. One of the samples contained Cr(VI) crystals, known as blooms, and had a Cr(VI) concentration approximately 40 times greater than the sample without blooms. The pH of the synthetic sweat solution had little effect on the Cr(VI) concentration determined for the sample containing blooms, whereas the Cr(VI) concentration determined for the sample without blooms increased with increasing pH. The Cr(VI) extracted in the synthetic sweat solutions was consistently lower than the amount extracted by the EPA 3060 alkaline extraction.

Chromium↗

PubMed1995

Sweat sodium and chloride analysis using BM/Hitachi 911 ion-selective electrodes.

The suitability of Hitachi 911 ion-selective electrodes to analyse neat sweat samples for sodium and chloride was investigated. Sweat samples obtained using the Gibson and Cooke method were analysed by flame photometry for sodium and coulometry for chloride. Specimens obtained by the Wescor Macroduct collection procedure were analysed by ion-specific electrodes. No significant differences between sodium and chloride results were found between the two different collection methods and analysis procedures. Analysis of neat sweat can reduce errors in sweat analysis by eliminating extraction and dilution stages. Errors could occur with use of a serum compensator in the calibration of ion-selective electrodes.

Chlorides↗

PubMed1976

[Calorimetric study of thermoregulatory mechanisms at the onset of sweating and during the menstrual cycle (author's transl)].

1 At the onset of sweating, tympanic (Tty), vaginal (Tva) and mean skin (Ts) temperature as well as the sudoral response were studied by direct and indirect calorimetry. Eight women with a normal ovulatory cycle were consecutively exposedt wice to 37 degrees C/20% rh during the follicular phase and again during the luteal phase. 2 Under our conditions, Tty may be used as an index of deep body temperature without any notable influence from ambient temperature. A weighting factor of chi = 0,7 was applied to the internal part of the body for the calculation of mean body temperature Tb. chi was determined by calorimetry, before and after the onset of sweating. 3 The onset of thermal sweating depends on a characteristic Tb corresponding to a specific caloric content of the body. Neither Tty, Tva, nor Ts, alone constitutes the specific stimulus leading to thermolysis by sweating. 4 The set point value (Tb "set") of the thermoregulatory system increases in the luteal phase, compared with that of the follicular phase. 5 Thermal regulation of the proportional control system shows a gain which is not modified during the menstrual cycle. 6 There is no relation between the shift of the set point value (Tb "set") and the increase of urine pregnandiol in the luteal phase. 7 The increase in basal body temperature and its maintenance during the post-ovulatory phase do not seem to be related to an increase in metabolic heat production.

Adult↗

PubMed1993

Sweat osmolality in some of the congenital diseases.

Sweat osmolality pattern was studied in Indian sub population of both controls and patients with congenital diseases. A Normal range for sweat osmolality was established for different age groups and sex (100-150 mmols/kg) and compared with the patients, who were clinically diagnosed as cystic fibrosis, Down's syndrome and mentally retarded cases. The study has revealed that sweat osmolality varies according to age and sex in normal population implying the effect of endocrinological changes associated with the onset of puberty. Further, it was also observed that an elevated sweat osmolality is not unique to cystic fibrosis alone, but seen among the Down's syndrome and some of the mentally retarded cases where in the etiology is traced to the inborn errors of metabolism.

Adolescent↗

PubMed1996

Enzyme immunoassay validation for qualitative detection of cocaine in sweat.

A solid-phase enzyme immunoassay (EIA) involving microtiter plates was modified for analysis of cocaine in sweat. Sweat was collected with the PharmChek sweat patch and drugs were eluted from the collection pad of the patch. The sweat contained primarily parent cocaine. The assay was determined to have cross-reactivity for cocaine of 102% relative to 100% for the benzoylecgonine (BE) calibrators and for cocaethylene of 148%. The optimum cutoff concentration for this modified assay, determined by receiver-operating characteristic curve analysis, was 10 micrograms/L cocaine or BE equivalents. At this concentration the assay had 94.5% sensitivity and 99.1% specificity vs gas chromatography-mass spectrometry (GC-MS) as an acceptable indicator of the true clinical state. The positive predictive value at a prevalence of 50% was 99%. Threshold analysis for positives suggested that the 95% confidence interval for a positive result by the EIA was between 12.5 and 15 micrograms/L and that quality-control samples at 5 and 15 micrograms/L could be run with each batch to certify the precision around the cutoff. All positive samples must be confirmed by GC-MS. The sensitivity and specificity of the overall analysis system (immunoassay screen and GC-MS confirmation) was 86% and 97%, with known cocaine dosing of volunteers as the acceptable indicator of the true clinical state.

Cocaine↗

PubMed1996

Sweat testing for benzodiazepines.

Thirteen subjects participated in a clinical study to determine the cumulative excretion, the time course, the dose-concentration relationship, and concentrations of diazepam in sweat following oral administration of single dose of the drug. Nordiazepam and oxazepam, two metabolites of diazepam, were also investigated. Sweat was collected by means of Sudormed sweat patch. Patches were removed at specified times over one week and drug content was determined by gas chromatography/mass spectrometry (GC/MS) in negative chemical ionization mode using deuterated internal standards. Irrespective of the time of collection, diazepam and nordiazepam were present, but oxazepam was never detected. Drugs were detectable in the 2 to 4-h period following the administration. Peaks of diazepam were obtained during the 48 to 72-h period. After the peak, a decrease of drug concentration was observed. Concentrations were in the range from 0.1 to 6.0 ng/patch for both drugs. After single administration of diazepam (10, 20, or 30 mg), drugs monitored in three groups of three subjects were suggestive to be dose related. All these data suggest that the sweat patch technology can be useful to document drug use over a week-long period of surveillance.

Administration, Oral↗

PubMed1997

Sweat analysis following pressure ischaemia in a group of debilitated subjects.

This article examines the application of a simple technique for the collection of sweat to the investigation of tissue metabolites in 11 debilitated subjects attending a rehabilitation unit. It is applicable to subjects with a range of clinical conditions. Sweat was collected at the sacrum with the subjects either seated in a wheelchair or lying in bed, which was representative of their usual daily routine. The tissues could be loaded during sweat collection by sacral support in either of these positions. Collections were made for about 10 hours and interface pressures were recorded on at least two occasions. After the prescribed period, the sweat pads were removed and a quantitative analysis of a range of metabolites was performed. Metabolite concentrations may reflect local tissue viability and responses to loading. In unloaded tissues the metabolite concentrations were similar to those observed in nondisabled subjects in an earlier study. During prolonged loading at relatively low levels of pressure, there was elevation in the levels of some metabolites; for example 39 and 28% increases for lactate and urea respectively. Successive measurements on an individual over a period of months showed variations, which were small compared to those observed in either groups of nondisabled or debilitated subjects. These observations suggest that the technique may be best applied in clinical practice to monitor sequential changes in individual subjects.

Adult↗

PubMed1997

Calcium homeostasis influences epidermal sweating in patients with vitiligo.

Patients with vitiligo have a decreased sweating response in both their lesional and non-lesional skin (n = 17) compared with healthy age- and sex-matched controls (n = 22) after stimulation with the acetylcholine agonist pilocarpine. The decreased cholinergic response of the dermal sweat glands in this patient group correlates with a significantly lower calcium concentration in sweat compared with controls. In addition, a significantly higher potassium concentration was found in the pigmented skin of these patients. The other fast exchange ions sodium and chloride are unaffected. In vitiligo, there was a marginal sweat induction after adrenergic stimulation in four of 10 patients tested whereas all controls (n = 10) did not show any response.

Acetylcholine↗

PubMed1995

Maximal sweating rate in humans.

We reviewed the literature concerning the maximal sweating rate (SRmax) during heat acclimatization, walking in desert heat and marathon running, and analyzed it from the viewpoint of sex, age, level of maximal oxygen uptake, and experimental conditions, i.e., ambient temperature, relative humidity, work intensity, work type, working duration, seasonal factors and the techniques of heat acclimatization. Exercise simulation, walking, running or bicycling, to induce the SRmax was conducted in a hot climatic chamber or in the desert. The SRmaxs due to marathon running were 1,000 to 1,200 g.h-1 in the cold season and 1,500 to 2,000 g.h-1 in the hot season. After several days of heat acclimatization, sweating capacity in the exercise simulation reached a maximum rate, over 2,000 g.h-1. There was a sexual difference in the SRmax, and the sweating capacity in the female was less than that in the male. Thus, the maximal sweating capacity in human was observed by prolonged moderate muscular exercise under thermal stress and internal and/or external heat loads.

Acclimatization↗

PubMed1953

Variation in the functional power of human sweat glands.

A method has been worked out for the measurement of the volume of sweat produced by individual glands. A special paper, impregnated with iodine, absorbs water in a uniform way and shows the area of wetting by a sharply defined blue dot. Indirect calibrations showed that 1 cm.(3) of water would form a spot of 700 cm.(2) area, and that this relation of volume to area was a constant one over a wide range. The actual volumes encountered in prints of the sweat glands were from 5 x 10(-9) to 4 x 10(-6) cm.(3). The relative activity of glands at any instant of time can be expressed by the statistical distribution of log diameter of the dots on the print. This distribution, which might at first sight seem rather artificial, has the advantage of being unaffected by a proportionate change in the output of water from each gland. Thus it is independent of the duration of contact between print paper and skin, and of changes in the average flow from the field as a whole. It is sensitive only to changes in the activity of glands relative to each other. The methods of printing and statistical analysis were used to study the relative activity of glands in a field of 22 mm. diameter. Glands of the forearm and back were studied both under direct stimulation with mecholyl and under the reflex stimulation of environmental heat, similar results being obtained with the two kinds of stimuli. Glands of the abdomen and leg, stimulated with mecholyl, were studied in one experiment. Detailed comparison of the dots in consecutive prints showed that the large dots remained large and the small dots continued to be small. These persistent differences in the outflow of water from adjacent glands were interpreted as being due to differences in the functional power of the glands. Repeated prints of the glands during a period of 75 minutes, in which the sweat flow was declining, showed that the relative activity of the glands remained constant. This meant that the set of glands, although differing greatly in power, varied together as a functional unit. Different regions of the body show not only the variation of glandular power within each small area, but also marked differences in the average power of glands belonging to the different regions. Glands of the back, for instance, show a much greater outflow than glands of the forearm when stimulated equally with a local injection of mecholyl. Equal rates of outflow, therefore, do not mean equal states of functional activity, unless the regions being compared are of equal functional power.

Hot Temperature↗

PubMed1992

Myoepithelial differentiation in benign sweat gland tumors. Demonstrated by a monoclonal antibody to alpha-smooth muscle actin.

One hundred and two cases of benign sweat gland tumors of the skin were studied for the presence of myoepithelial cells specifically identified by a monoclonal antibody to alpha-smooth muscle actin on paraffin-embedded tissues. The monoclonal antibody gave a positive result in 12 of 12 cases of cylindroma, 14 of 16 cases of spiradenoma, 2 of 2 cases of apocrine tubular adenoma (papillary eccrine adenoma), 5 of 5 cases of apocrine hidrocystoma, 5 of 5 cases of hidradenoma papilliferum, and in 10 of 10 cases of syringocystadenoma papilliferum. Rare myoepithelial cells were detected in only 1 of 10 cases of mixed tumor, apocrine type. There was no immunoreactivity for alpha-smooth muscle actin in eccrine hidrocystoma (2 cases), mixed tumor of eccrine type (2 cases), syringoma (7 cases), hidroacanthoma simplex (1 case), eccrine poroma (14 cases), clear cell hidradenoma (15 cases), and in 1 case of eccrine syringofibroadenoma. Our data support the concept that myoepithelial cells are seen in most sweat gland tumors considered to differentiate toward the secretory coil of the normal sweat gland. In contrast, myoepithelial cells are absent in tumors showing differentiation toward the excretory (ductal) component of the gland.

Actins↗

PubMed1995

Significance of lipopigments with fingerprint profiles in eccrine sweat gland epithelial cells.

Lipopigments with fingerprint profiles in eccrine sweat gland epithelial cells are regular findings in childhood NCL. They have also been described in adult NCL (ANCL) a few times, but not consistently. However, they have been considered nonspecific when not matched by similar abnormal profiles in noneccrine sweat gland epithelial cells. These conflicting reports may pose a diagnostic dilemma as outlined in the following 2 examples. Patient 1 is a 20-year-old man who developed severe tetraparesis and dementia over 2 years. Electroencephalogram was abnormal with epileptiform discharges. The patient died at age 21 years without autopsy; no other relatives are known to have a similar disease. Patient 2, a 49-year-old woman, developed ataxia and gait abnormalities when 44 years old, and, later, psychosis and dementia. The patient is still alive; no other family members are similarly affected. Both patient lacked evidence of a retinopathy clinically, funduscopically, and by electroretinography. Both patients showed lipopigments within secretory eccrine sweat gland epithelial cells which harbored unequivocal fingerprint profiles, but not within noneccrine sweat gland cells. Regular lipofuscin was observed in other cells, including skeletal muscle fibers of patient 2.

Adult↗