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At least 163 records · Page 9Linked to original sources
PubMed2000

Reliability of sweat-testing by the Macroduct collection method combined with conductivity analysis in comparison with the classic Gibson and Cooke technique.

UNLABELLED: This study was to ascertain the reliability of sweat-testing by the Macroduct collection method combined with conductivity analysis (MCS) compared with the Gibson and Cooke technique (GCT). Sweat stimulation by pilocarpine iontophoresis was identical for both procedures, sweat being collected for 30 min on a filter paper on one forearm and in the coil of the Macroduct collector on the other. Chloride, sodium and potassium concentrations were chemically analysed both on paper-eluted and tube-collected sweat; the latter was also analysed using a conductivity analyser. Chemical analyses were compared with conductivity analyses. This prospective study was carried out on 318 subjects with MCS (118 CFs, 200 controls) and on 305 of them with the GCT (113 CFs, 192 controls). The pilocarpine iontophoresis produced adequate sweat in 96.4% of collections with GCT and in 90.9% with the MCS. Sensitivity and specificity of the Macroduct/conductivity system were comparable to the GCT. No patient detected by the GCT technique was considered negative by conductivity, but one GCT positive was "borderline" with the MCS. Six non-CF subjects identified as negative by the GCT (3.3%) were in the borderline range with the MCS. CONCLUSION: Sweat-testing by the MCS has acceptable sensitivity and specificity when performed by trained CF sweat-testing technicians. Additional studies will be required to find out if these results can be confirmed in small clinics and hospitals where testing is done infrequently. Wherever the MCS is used all positive or borderline results should be confirmed by the GCT at a reference Cystic Fibrosis Center.

Adolescent↗
PubMed1991

Roles of Ca and cAMP on C1 channel activity in cystic fibrosis sweat clear cells as studied by microsuperfusion and cell volume analysis.

In an attempt to study regulation of C1 channels in intact sweat secretory coils in cystic fibrosis and controls in the least invasive manner, isolated secretory coils were superfused with various drugs and K-efflux was determined as an indirect measure of C1 movement. C1 channel activity was also determined from the drug-induced cell volume increase in gramicidin (GC)-treated dissociated eccrine clear cells. We observed that while MCh-induced K-efflux from the CF secretory coils was entirely normal, K-efflux in the presence of isoproterenol (ISO), forskolin (FK), or IBMX was absent in CF, suggesting that these agents failed to stimulate C1 movement. C1 channel activity of dissociated CF clear cells, as studied by cell volume analysis, was entirely normal when stimulated by Ca-elevating agents but was defective when stimulated by cAMP-elevating agents. TPA (phorbol ester) does not appear to stimulate C1 channel activity nor does it modify the effect of other agents. The following observations from the present and previous studies are not necessarily consistent with the traditional thesis that the observed C1 movement is due to cAMP: CT-cAMP had no effect on cell swelling or on K-efflux; ISO is more potent in accumulating tissue cAMP than IBMX yet the latter is more potent in stimulating K-efflux; IBMX increases cytoplasmic [Ca] yet is unable to stimulate K-efflux in CF; K-efflux stimulated by cAMP-elevating agents was inhibited by removal of Ca from the bath; and, cell swelling of GC-treated cells in response to cAMP elevating agents was inhibited by removal of Ca. The inability of IBMX to stimulate C1 channels in the face of elevated cytoplasmic [Ca] and cAMP in CF cells deserves further scrutiny.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Whole body sweat collection in humans: an improved method with preliminary data on electrolyte content.

Previous methods used to collect human sweat for electrolyte analysis have been criticized because they involve only regional sampling or because of methodological problems associated with whole body-washdown techniques. An improved method for collection of whole body sweat from exercising subjects is described. It involved construction of a plastic frame that supports a large plastic bag within which the subject exercises. The subject and the equipment are washed with distilled, deionized water before exercise begins. After exercise is completed, the subject and equipment are again washed with water containing a marker not present in sweat (ammonium sulfate). Total sweat loss is calculated from the change in body mass, and the volume of sweat not evaporated is calculated from dilution of the added marker. Recovery of added water was 102 +/- 2% (SD) of the added volume, and recovery of added electrolytes was 99 +/- 2% for sodium, 98 +/- 9% for potassium, and 101 +/- 4% for chloride. Repeated trials (n = 4) on five subjects to establish the reproducibility of the method gave a coefficient of variation of 17 +/- 5% for sodium, 23 +/- 6% for potassium, and 15 +/- 6% for chloride. These values include the biological variability between trials as well as the error within the method. The biological variability thus appears to be far greater than the methodological error. Normal values for the composition of sweat induced by exercise in a hot, humid environment in healthy young men and women were (in mM) 50.8 +/- 16.5 sodium, 4.8 +/- 1.6 potassium, 1.3 +/- 0.9 calcium, 0.5 +/- 0.5 magnesium, and 46.6 +/- 13.1 chloride.

Adult↗
PubMed1991

Changes in cholinergic sweat gland activation in diabetic neuropathy identified by computerised sweatspot analysis.

Peripheral small-fibre denervation has been reported to result in decreased activation of eccrine sweat glands to muscarinic cholinergic agents. Using computerised image-analysis of pilocarpine-activated sweatspot prints of a 4 cm2 area of the dorsum of the foot in 79 randomly selected diabetic patients we have identified a group of neuropathic patients (18%) with decreased sweatspot activation (less than 20/cm2), and a smaller group (6%) of younger patients with less marked neuropathy who had increased activation (greater than 132/cm2), probably resulting from denervation supersensitivity. The associations between sweatspot density and other conventional tests of peripheral nerve function were weak. The prevalence of abnormal sweatspot density, 24%, was similar to that of other tests, except thermal thresholds at the feet (35-37%), which were not correlated with sweatspot activation, suggesting that diabetic neuropathy has differing effects on afferent and efferent small fibres. The method is rapid and reproducible (median coefficient of variation 14%) and its ability to identify patients with increased, as well as decreased, peripheral nerve function may be of value in the characterisation and longitudinal follow-up of small-fibre abnormalities in diabetes.

Adult↗
PubMed1996

Congenital bilateral absence of the vas deferens (CBAVD) and cystic fibrosis transmembrane regulator (CFTR): correlation between genotype and phenotype.

To assess better the link between congenital bilateral absence of the vas deferens (CBAVD) and cystic fibrosis (CF), we compared sweat chloride values, analysis of the CFTR intron 8 poly(T) tract length and analysis of 10 exons in a population of 38 patients with CBAVD. The data indicate that this population can be divided into three groups of patients. In the first group of 15 patients with abnormal sweat chloride (> 60 mmol/l), the frequency of CF mutations is high. In the second group of 18 patients with equivocal sweat chloride (between 40 and 60 mmol/l), the frequency of the 5T variant is high; 6 patients have a delta F508 mutation and a 5T variant and 1 patient is homozygous for the 5T variant; a 5T variant has been detected in 3 other patients, and a delta F508 mutation in another patient. A third group of 5 patients is probably not related to CF: these patients have other congenital abnormalities of the urogenital tract, low chloride values (< 40 mmol/l) and apparently no abnormality of the CF gene.

Adult↗
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↗
PubMed1992

Monoclonal antibody analysis of keratin expression in carcinomas of sweat glands.

Characteristics of keratins of five carcinomas of sweat gland origin were immunohistochemically investigated with several antikeratin monoclonal antibodies with differing specificities. Specimens were obtained from two cases of mucinous carcinoma of the skin, two cases of classic type of eccrine adenocarcinoma, and a case of eccrine porocarcinoma. The tumor cells of mucinous carcinoma expressed only simple epithelial keratins. In a case of eccrine adenocarcinoma, simple epithelial keratin 19 was diffusely expressed. The expression of the other simple epithelial keratins was confined to the luminal cells, whereas the remaining tumor cells further expressed stratified epithelial keratins. Eccrine porocarcinoma and a second case of eccrine adenocarcinoma did not express simple epithelial keratins, although stratified epithelial keratins were diffusely expressed. These data suggest that carcinomas of sweat glands express various combinations of simple and stratified epithelial keratins. Development of additional data along these lines may help to further define their classification.

Adenocarcinoma↗
PubMed1994

Sweat testing for heroin, cocaine, and metabolites.

Although a variety of drugs have been detected in sweat, little information is available on the characteristics of drug excretion in sweat under controlled-dosing conditions. A series of clinical studies were designed to determine the identity, concentration, time course, dose dependency, and variability of drug and metabolite excretion in sweat following administration of single doses of cocaine and heroin to human subjects. Sweat was collected by means of a sweat patch that could be worn for a period of several days to several weeks at a time, resulting in accumulation of drug in the patch. Sweat patches were removed at specified times and frozen until analyzed by gas chromatography--mass spectrometry. Cocaine and heroin were the major analytes excreted in sweat following their administration. Smaller amounts of cocaine metabolites were also detected following cocaine administration. 6-Acetylmorphine appeared rapidly after heroin administration and continued to increase while heroin content decreased, suggesting that heroin was undergoing hydrolysis in the sweat patch. Cocaine appeared in sweat within 1-2 hours and peaked within 24 hours in an apparent dose-dependent manner. Analysis of duplicate adjacent patches from individual subjects who had been administered cocaine provided similar quantitative results, suggesting that intrasubject variability was relatively low, whereas intersubject variability was high. These observations regarding the excretion of cocaine and heroin analytes in sweat have important forensic implications to other fields such as hair analysis. Sweat excretion could be an important mechanism by which drugs enter hair. These data also suggest that the sweat patch could serve as a useful monitoring device in surveillance of individuals in treatment and probation programs.

Administration, Inhalation↗
PubMed1998

Buccal cell DNA mutation analysis for diagnosis of cystic fibrosis in newborns and infants inaccessible to sweat chloride measurement.

OBJECTIVES: To assess the application of DNA-based cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation analysis as a primary cystic fibrosis (CF) diagnostic test in preterm and term newborns and infants for whom the quantitative pilocarpine iontophoresis test (QPIT) cannot be used. DESIGN: Retrospective survey. SETTING: DNA Diagnostic Laboratory, Children's Hospital, Boston, Massachusetts. Buccal cell DNA samples were received from inpatients, outpatients, and three neonatal intensive care units. OUTCOME MEASURE: Detection of at least 1 of 12 CFTR mutations. PATIENTS: Between November 1, 1992, and April 30, 1994, 28 newborns and infants under 12 months of age at risk for CF had CFTR DNA mutation analysis performed because a sweat chloride (SC) value could not be obtained. QPIT was either not performed (infant weight <2 kg, QPIT not available at site of hospitalization, or infant not accessible to QPIT laboratory) or was inconclusive (sweat volume <75 mg or indeterminate SC [>/=40, <60 mEq/L]). The postnatal age at time of testing ranged from 1 day to 11 months, and gestational age at birth from 25 to 40 weeks. RESULTS: Six (21%) of 28 infants with unobtainable or indeterminate QPIT had 1 or 2 CFTR mutations detected. Immediate CF diagnosis by direct detection of 2 CFTR mutations was made in 5 of these 6 patients. Definitive CF diagnosis in the infant with 1 CFTR mutation was delayed until an elevation in SC could be documented. The patients with no CFTR mutations detected had a low likelihood of CF. CONCLUSIONS: For infants in whom CF is suspected but QPIT cannot be obtained, buccal cell DNA-based CFTR mutation analysis can be used as a rapid, noninvasive primary diagnostic test. This simple mode of DNA collection may aid in the diagnosis of other inherited disorders in newborns.

Cystic Fibrosis↗
PubMed1982

Mucolipidosis IV, a sialolipidosis due to ganglioside sialidase deficiency.

A female patient of Italian, non-Jewish, descent, 22 years of age, with cloudy corneae, capsular lens opacities and severe and progressive mental and motor deterioration is described. Ultrastructural examination of a skin biopsy sample showed storage of membranous cytoplasmic bodies in Schwann cells, vessel walls, fibroblasts, smooth muscle fibres and sweat glands, and the presence of some electron-lucent vacuoles, filled with fibrillo-granular material, in sweat glands. Biochemical analysis of cultured fibroblasts (from skin explant) showed a complete deficiency of the sialidase acting on gangliosides, while the sialidase acting on sialyllactose and MU-NeuAc, and several lysomal hydrolases were normal. The urine sediment analysis showed accumulation of all phospholipid species, of several glycolipids and of gangliosides, especially of the polysialylated species. We conclude that the patient under examination is affected by Mucolipidosis IV and the term 'sialolipidosis' is suggested for this inborn disorder.

Adult↗
PubMed2006

Application of ion mobility spectrometry in cases of forensic interest.

Ion mobility spectrometry (IMS) has been known as an analytical technique since the late 1960s and early 1970s. To date, it has been successfully utilized for the detection of environmental pollutants, warfare agents, explosives, herbicides, pesticides, petroleum products as well as for the detection of prescription and illicit drugs. In this paper the authors describe the use of the IMS technology in cases of forensic interest in Salzburg, Austria. We report the use of the IMS methodology for the rapid analysis of hallucinogenic mushroom material as well as for the analysis of samples taken after an explosion. A new application of the IMS technology for the analysis of postmortem sweat samples for drugs is also presented.

Adult↗
PubMed2002

Different morphotypes of functional dentition in the lower molar region of tabby (EDA) mice.

OBJECTIVES: To sort and classify the highly variable lower molar dentition in tabby (Ta) mice postnatally. The Ta syndome is homologous to the anhidrotic (hypohidrotic) ectodermal dysplasia (EDA) in human and includes severe developmental defects of teeth, hair and sweat glands. DESIGN: Analysis of tooth shape and cusp pattern and measurement of the mesio-distal crown length. SETTING AND SAMPLE POPULATION: Institute of Experimental Medicine, Academy of Sciences, Prague. Fixed heads of 107 tabby (Ta) homozygous and hemizygous mice and 90 wild type mice aged from post-natal day 11 to adulthood, collected during 1995-2001. OUTCOME MEASURE: Identification of distinct morphotypes of Ta dentition. Reduced tooth length in Ta teeth and specific differences in tooth length between distinct morphotypes. RESULTS: The variable dentitions in the lower molar region of Ta mice were classified in two basic morphotypes I and II. The morphotype I was further subdivided into particular morphotypes Ia, Ib and Ic. Proportion of the basic morphotypes I and II was different in the offspring of heterozygous (84% and 12%) compared with homozygous + hemizygous (45% and 52%) mothers. The proportions of particular morphotypes within a basic morphotype were similar in both offspring groups. CONCLUSION: The identification of the distinct morphotypes made possible to classify the structural variability of the mandibular functional dentition in Ta mice.

Animals↗
PubMed2002

Cystic fibrosis in a child from Syria.

We describe a Syrian child with typical features of severe cystic fibrosis (CF) phenotype and a positive sweat test. DNA analysis confirmed homozygosity for the delta F508 mutation on chromosome 7. This report stresses the need to draw attention to and consider CF in Arab populations. The frequency and distribution of delta F508 in the Middle East are reviewed.

Arabs↗
PubMed2000

Genotype analysis and phenotypic manifestations of children with intermediate sweat chloride test results.

STUDY OBJECTIVES: Cystic fibrosis (CF) is one of the most common inherited diseases among whites. Since the cloning of the CF transmembrane conductance regulator (CFTR) gene, a number of studies have focused on associations between the genotype and phenotype in CF. This had led to the progressive identification of new groups of patients, including those who have mild lung disease and those who have normal sweat chloride values (< 60 mEq/L). The aim of the present work was to provide information on the genotype and the phenotypic characteristics of children with intermediate-range sweat chloride test results. PATIENTS AND RESULTS: We focused on children referred to the pulmonary department for various types of pulmonary disease and who had several sweat chloride test results with median values in the range of 40 to 60 mEq/L. Twenty-four patients over a 10-year period were enrolled (mean age, 4.8 years). Respiratory manifestations at initial evaluation included recurrent bronchitis, wheezing, chronic cough, and pneumonia. The duration of the follow-up ranged from 0.5 to 10.5 years. Sputum cultures revealed the presence of Haemophilus influenzae (10 children), Staphylococcus aureus (4 children), and Pseudomonas aeruginosa (3 children). Pancreatic insufficiency was found in two patients. Analysis of the entire coding sequence allowed identification of 16 known mutations in CFTR gene. Fifteen chromosomes (31.2%) carried a mutation in CFTR gene and one allele carried two mutations. Three patients were homozygous or double heterozygous (DeltaF508/DeltaF508, DeltaF508/3849 + 10 kb C-->T, S1235R/G551D). The 5-thymidine allele was identified in four children. CONCLUSION: These results indicate an higher frequency of CFTR gene mutations in patients with borderline sweat chloride test results, compared to data reported in the general population. They lead to the recommendations for complete pulmonary and GI investigations in this group of patients, as well as assiduous care and medical follow-up.

Adolescent↗
PubMed2001

In vivo confocal Raman microspectroscopy of the skin: noninvasive determination of molecular concentration profiles.

Confocal Raman spectroscopy is introduced as a noninvasive in vivo optical method to measure molecular concentration profiles in the skin. It is shown how it can be applied to determine the water concentration in the stratum corneum as a function of distance to the skin surface, with a depth resolution of 5 microm. The resulting in vivo concentration profiles are in qualitative and quantitative agreement with published data, obtained by in vitro X-ray microanalysis of skin samples. Semi-quantitative concentration profiles were determined for the major constituents of natural moisturizing factor (serine, glycine, pyrrolidone-5-carboxylic acid, arginine, ornithine, citrulline, alanine, histidine, urocanic acid) and for the sweat constituents lactate and urea. A detailed description is given of the signal analysis methodology that enables the extraction of this information from the skin Raman spectra. No other noninvasive in vivo method exists that enables an analysis of skin molecular composition as a function of distance to the skin surface with similar detail and spatial resolution. Therefore, it may be expected that in vivo confocal Raman spectroscopy will find many applications in basic and applied dermatologic research.

Adult↗
PubMed2006

New tests for cystic fibrosis.

Most patients presenting with symptoms and signs of CF are still diagnosed on the basis of a sweat test. CFTR mutation analysis is useful in confirming the diagnosis, screening family members, newborn screening programmes and in those with borderline or normal sweat tests with a high index of suspicion. Nasal PD can also be helpful in the latter group, although there are a number of caveats to its use and interpretation.

Biomarkers↗