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At least 181 records · Page 10Linked to original sources
PubMed1984

Heat exchange following atropine injection before and after heat acclimation.

The effect of saline and atropine injection (2 mg, im) on eight healthy male subjects before and after heat acclimation was studied while each subject walked on a treadmill (1.34 m X s-1) in a hot-dry environment (ambient temperature = 48.4 degrees C, dew-point temperature = 20.5 degrees C). Partitional calorimetric analysis was done for the periods in which maximum sweat inhibition occurred (30 min). Mean skin temperature, rectal temperature, and heart rate were continuously observed. Evaporative loss from the skin was calculated by changes in body weight (Sauter balance); heat transfer coefficients were defined by Nishi equations. A prediction of sweat inhibition based on an analysis of heat storage and its effect on a theoretical temperature, which can be graphed on a psychrometric chart, was developed. A rational effective temperature (ET) defined as the operative temperature at the intersection of the 50% rh, which encompasses total heat exchange, was used to compare the effects of atropine before and after heat acclimation. The results show that heat acclimation reduced ET by approximately 2.5 degrees C when compared with the unacclimated state after atropine injection. Thus heat acclimation reduces the hazards of heatstroke caused by exercise in the heat with atropine injection.

Acclimatization↗
PubMed1983

Laboratory diagnosis of cystic fibrosis.

The demonstration of abnormally high concentrations of electrolytes in eccrine sweat is still the only practical laboratory procedure available for diagnosis of cystic fibrosis. Properly performed, the sweat test is very reliable, but there are many published reports that all of the methods in current use frequently generate incorrect diagnoses. Analysis of potential for error in sweat test methods shows that of the three essential phases involved, stimulation, collection, and analysis, the major cause of intrinsic inaccuracy occurs in the collection process. In this case the problem is due to condensate formation, which leads to the subsequent analysis of nonrepresentative sweat. Human error is also an important cause of false results and is a direct function of the number of critical manual operations involved in the technic. This review provides a critical examination of sweat test methods, identifying problem areas and suggesting ways to improve procedures in the interests of clinically reliable laboratory data in support of diagnosis.

Adolescent↗
PubMed1985

Liquid-chromatographic determination of chloride in sweat from cystic fibrosis patients and normal persons.

Chloride concentrations in sweat were measured by "vacancy liquid chromatography," a technique in which anions eluting from an ion-exchange column in the presence of an elution buffer which absorbs at 280 nm cause a decrease in absorbance proportional to the concentration of the anion. Less than 1 microL of sweat suffices for this analysis, which takes 5 min per sample. Results were comparable to those obtained by conventional titrimetric determination of chloride. Sweat from cystic fibrosis patients had higher (104 +/- 26 mmol/L) chloride concentrations than sweat from normal persons (16 +/- 7 mmol/L). This technique can be used in the diagnosis of cystic fibrosis.

Child, Preschool↗
PubMed1979

Christ-Siemens-Touraine syndrome--a clinical and genetic analysis of a large Brazilian kindred: II. Affected males.

We describe 13 males with Christ-Siemens-Touraine syndrome from one family. History and examination were supplemented by three sweat tests and dermatolglyphic analysis. Some of the patients had two uncommon findings (onychodystrophy and excessive lacrimation), and five had an "incomplete" form of the syndrome. Four signs (distal phalanges of fingers and toes radially and tibially deviated, respectively; facial hypochromic spots; large occipitofrontal circumference) seem to be described for the first time. The segregation proportion in the sibships with at least an affected male was found to be normal (1:1) in 44 series of data (43 from the literature), where a high ascertainment bias was present (155 affected and 68 normal males).

Adolescent↗
PubMed1997

Qualitative detection of opiates in sweat by EIA and GC-MS.

Sweat was collected with the PharmChek sweat patch, and drugs were eluted from the collection pad of the patch. A solid-phase enzyme immunoassay (EIA) using microtiter plates was modified for the analysis of opiates in sweat. After opiate administration, sweat contains primarily parent opiate (heroin, codeine) and lipophilic metabolites (6-monoacetylmorphine [6-MAM]). The immunoassay was determined to have a cross-reactivity with codeine of 588%, with hydrocodone of 143%, with diacetylmorphine of 28%, and with 6-MAM of 30% relative to 100% for the morphine calibrators. The optimum cutoff concentration for this modified assay was determined by receiver operator characteristic analysis using 215 patches from 95 subjects to be 10 ng/mL morphine equivalents. At this cutoff concentration the assay had a diagnostic sensitivity of 86.9% and a diagnostic specificity of 92.8% versus gas chromatography-mass spectrometry (GC-MS), which was the reference method. The positive predictive value at a prevalence of 50% was 86%. The intra-assay precision at 10 ng/mL was 7.8%, and the interassay coefficient of variation (CV) was 39%. Analysis of spiked patches around the cutoff gave a percent positive threshold of approximately 50% between 10 and 15 ng/mL and a 95% confidence level for a positive result by the EIA between 20 and 25 ng/mL. Eighteen possible adulterants that could be injected into or under the patch were studied. Two (tile cleaner and detergent) can cause false-positive responses in the immunoassay. Two adulterants reduced response to spiked drug (Visine eye drops and Ben Gay ointment), which could cause a false-negative response. All results were confirmed by GC-MS. The clinical sensitivity and specificity for detecting drug use by analyzing sweat collected from human subjects following known doses of codeine (0, 30, and 60 mg orally) or heroin (20 mg intravenously) were 76 and 100%, respectively.

Calibration↗
PubMed1993

Release of thiurams and carbamates from rubber gloves.

A method for quantitative determination of thiuram and carbamate derivatives released from rubber gloves into synthetic sweat is presented. The analysis was based upon determination of ester derivatives using gas-chromatography/mass spectrometry and isotope-dilution. The detection limit was 0.1 mg thiuram/carbamate in 200 ml synthetic sweat (0.5 ppm). The release of thiurams and carbamates from 5 household and 5 surgical types of gloves into synthetic sweat was determined. Each of the natural rubber gloves released varying amounts of thiurams (0-4.3 mg) as well as carbamates (0-8.1 mg). 22 thiuram-sensitized patients were patch tested with pieces of the gloves. Gloves releasing considerable amounts of thiurams and/or carbamates seemed to cause more positive patch test reactions in these patients than gloves releasing smaller amounts. Surgical gloves made from natural rubber caused a substantial larger number of positive patch test reactions than household gloves made from natural rubber. The amounts released per cm2 of the gloves were of the same order of magnitude as the content per cm2 patch test of thiuram mix, diluted 1:10. The accessibility of a quantitative, chemical analysis for thiurams and carbamates released from rubber gloves makes it reasonable to ask for declarations of rubber gloves. Proposals for threshold values for release of thiurams and carbamates from rubber gloves may be given in the future.

Carbamates↗
PubMed1999

Identification of pituitary adenylate cyclase activating polypeptide (PACAP) and PACAP type 1 receptor in human skin: expression of PACAP-38 is increased in patients with psoriasis.

Morphological and biochemical evidence is presented for the presence of pituitary adenylate cyclase activating peptide (PACAP) and the high-affinity PACAP-1 receptor subtype in human skin. Immunohistochemical analysis revealed PACAP-immunoreactivity (IR) to be present predominantly in dermal nerve fibers close to the dermal-epidermal border, hair follicles, blood vessels and sweat glands. Radioimmunoassay, chromatographic analysis and Western blotting revealed this PACAP-IR to be PACAP-38 whereas the second molecular form, PACAP-27, is absent. In tissue of psoriasis patients significantly more PACAP-38 protein was detected as compared to normal skin. Using RT-PCR, the expression of a high-affinity PACAP-1 receptor in human skin was observed. These results indicate a possible role for PACAP-38 in inflammatory processes of psoriasis.

Antibodies, Monoclonal↗
PubMed1985

Detection of cystic fibrosis heterozygotes using a modified loading with bromide.

A three day loading with sodium bromide was performed in 19 healthy controls, 16 definite cystic fibrosis heterozygotes, and 14 homozygote patients with cystic fibrosis. After three days sodium, potassium, chloride, and bromide were determined in serum and sweat. Using a multivariate discriminant analysis two nonelementary functions with the features sodium index, bromide index, potassium index, and chloride in sweat allowed us to identify the three groups. The reclassification of the probands, however, was correct in only 69.3%. A second analysis with the groups of controls and heterozygotes only resulted in a unidimensional nonelementary function with the features potassium index, bromide/sodium in sweat, and sodium index. The reclassification of the probands was correct in 91.4%. The discriminant values were 8.28 +/- 0.96 in the controls and 11.67 +/- 1.03 in the heterozygotes with an overlap of twice the standard deviations between 9.61 and 10.20.

Administration, Oral↗
PubMed1979

Christ-Siemens-Touraine syndrome--a clinical and genetic analysis of a large Brazilian kindred: I. Affected females.

A total of 27 women of a Brazilian kindred are described as having one or more signs of the Christ-Siemens-Touraine syndrome. The history and physical examination were supplemented by four sweat tests and dermatolglyphic analysis. It is suggested that this syndrome has two forms -- a major form (in males) and a minor one (in females). Two signs verified in some of our patients (mosaic patchy distribution of body hair and radial deviation of distal phalanges of index fingers) seem to be here described for the first time. A review of the literature shows a corrected sex ratio between 1 M: 1.21 F and 1 M: 2.38 F among affecteds. Since the manifestation rate of the gene among carriers was estimated at about 0.70, the actual sex ratio is expected to be not lower than 1 M: 1.40 F. Contrary to a general opinion, affected females outnumber affected males.

Adult↗
PubMed2003

[Molecular genetics principles in cystic fibrosis. An example of genetic illness in pneumology].

The generalized exocrinopathy cystic fibrosis (CF) is caused by molecular lesions in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The basic defect of this autosomal-recessive disorder manifests in decreased permeability for chloride ions across the apical epithelial membrane. Of the more than 1,000 known CFTR mutations the most frequent mutation F508del occurs on about 70% of North- and Mideuropean CF chromosomes. CFTR mutations are also causatively involved in male infertility, pancreatitis and several airway diseases like disseminated bronchiectasis. The differential diagnosis between CF, other CFTR-opathies and diseases of unrelated etiology can be achieved by the assessment of clinical symptoms, CFTR mutation analysis and electrophysiological bioassays (sweat test, nasal potential difference, intestinal current measurements).

Chromosome Aberrations↗
PubMed1998

Target-dependent development of the vesicular acetylcholine transporter in rodent sweat gland innervation.

Descriptive studies have delineated a developmental change in neurotransmitter phenotype from noradrenergic to cholinergic in the sympathetic innervation of sweat glands in rodent footpads. Transplantation and culture experiments provide evidence that interactions with the target tissue induce this change. Recent studies with an antiserum that recognizes the vesicular acetylcholine transporter (VAChT) suggest, however, that the development of cholinergic function in sympathetic neurons, including those that innervate sweat glands, occurs prior to and does not require target contact. To clarify these apparently contradictory findings, we directly compared the appearance of VAChT immunoreactivity in the sympathetic neurons that innervate sweat glands with the time that axons contact this target. We find that VAChT immunoreactivity is not detectable in either the axons or cell bodies of sweat gland neurons until several days after target innervation. Before and during VAChT acquisition, the developing sweat gland innervation contains vesicular stores of catecholamines. An analysis of mutant mice that lack sweat glands was undertaken to determine whether VAChT expression requires target interactions and revealed that VAChT does not appear in the absence of glands. These findings, together with previous studies, confirm the target dependence of cholinergic function in the sympathetic neurons that innervate sweat glands.

Acetylcholine↗
PubMed1986

Quantitative analysis of the local effect of skin temperature on sweating.

Effects of local skin temperature on sweat gland activity were analyzed quantitatively by measuring changes in the rates of thermal sweating and of drug-induced sweating by local heating. The data indicates that a rise in local temperature causes an accelerated increase in the rate of sweat production, the Q10 being around 2.5 regardless of the basal sweat rate with some individual variations. Local heating apparently facilitates transmitter release at the neuroglandular junction and augments glandular responsiveness, their significances being comparable.

Adult↗
PubMed1988

Prenatal diagnosis of cystic fibrosis: microvillar enzymes and DNA analysis compared.

We have established reference ranges for three microvillar intestinal enzymes--alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.1), and leucine aminopeptidase (EC 3.4.1.1)--measured in amniotic fluid in a reference population of 1875 women presenting for routine amniocentesis. These data were derived for use in prenatal diagnostic studies in a population at risk (1:4) for cystic fibrosis. False-positive or indeterminate results were noted for fewer than 3.5% of all low-risk cases for each enzyme evaluated. Total alkaline phosphatase and its isoenzymes and leucine amino-peptidase and gamma-glutamyltransferase were measured in amniotic fluid sampled between the 15th and 19th weeks of gestation. Restriction fragment length polymorphism analysis of DNA was also performed when possible. In 52 cases examined for cystic fibrosis thus far, 46 were diagnosed on the basis of DNA analysis and (or) by sweat testing; for the other six cases, only abnormal enzyme results were obtained before termination of pregnancy. Predictions based on microvillar enzyme results were falsely negative in three cases. In only one case was there a discrepancy between enzyme results and DNA analysis. Diagnostic accuracy was highest during the 17th and 18th week of gestation. Preliminary results suggest the false-negative rate of this diagnostic strategy may be greater than or equal to 10%.

Alkaline Phosphatase↗
PubMed1992

[Nicotine excretion by the apocrine and eccrine sweat in smokers and passive smokers].

Specimens of apocrine and eccrine sweat collected without and after pilocarpine stimulation from smokers and non-smokers exposed to tobacco smoke were investigated for the presence of nicotine. The concentrations were determined by radioimmunoassay, so that the values obtained represent the concentrations of nicotine plus its metabolites, e.g. cotinine. Measurable nicotine concentrations were found in all samples. The levels measured in apocrine sweat were higher than those in eccrine sweat. The presence of unchanged nicotine in sweat was revealed by GC/MS.

Adolescent↗
PubMed1981

Effect of a precooling maneuver on body temperature and exercise performance.

Twelve subjects exercised to exhaustion at an ambient temperature of 18 degrees C on a bicycle ergometer with the load being stepwise increased. On one day, exercise was preceded by a precooling maneuver. In the precooling tests, deep body temperature attained values of about 1 degree C lower than in the control tests. There was no indication of metabolic cold defense reactions being evoked throughout the exercise period. In the precooling tests, heart rate was significantly lower than in the controls, but the mean maximum work rate, peak oxygen uptake (VO2), time to exhaustion, and total work were not reduced, i.e., work rate and VO2 were increased for a given heart rate. In the three subjects with the lowest maximum work rates, total work and exhaustion time and, in two cases, maximum work rate were increased after precooling. The onset of sweating occurred at higher work rates but at lower core, mean skin, and mean body temperature after precooling. However, the accumulated sweat secretion was considerably smaller after precooling, indicating less thermoregulatory effort.

Body Temperature↗
PubMed2003

Combined in vivo confocal Raman spectroscopy and confocal microscopy of human skin.

In vivo confocal Raman spectroscopy is a noninvasive optical method to obtain detailed information about the molecular composition of the skin with high spatial resolution. In vivo confocal scanning laser microscopy is an imaging modality that provides optical sections of the skin without physically dissecting the tissue. A combination of both techniques in a single instrument is described. This combination allows the skin morphology to be visualized and (subsurface) structures in the skin to be targeted for Raman measurements. Novel results are presented that show detailed in vivo concentration profiles of water and of natural moisturizing factor for the stratum corneum that are directly related to the skin architecture by in vivo cross-sectional images of the skin. Targeting of skin structures is demonstrated by recording in vivo Raman spectra of sweat ducts and sebaceous glands in situ. In vivo measurements on dermal capillaries yielded high-quality Raman spectra of blood in a completely noninvasive manner. From the results of this exploratory study we conclude that the technique presented has great potential for fundamental skin research, pharmacology (percutaneous transport), clinical dermatology, and cosmetic research, as well as for noninvasive analysis of blood analytes, including glucose.

Arm↗