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Cystic fibrosis in patients over 40 is rare. We report a 52-year-old woman in whom cystic fibrosis was confirmed by sweat analysis. This patient represents the oldest cystic fibrosis patient (with confirmatory sweat chlorides) ever described. We conclude that any patient with the appropriate clinical presentation, regardless of age, should be investigated for cystic fibrosis.
There are few data on sweat analysis in Down's syndrome. We studied 25 children with Down's syndrome and obtained sweat samples by pilocarpine iontophoresis. Sweat osmolality was elevated in Down's syndrome compared to normal. The results of sweat testing must be regarded with caution when cystic fibrosis is suspected in children with Down's syndrome.
Several amperometric biosensors have been developed and applied for the non invasive determination of metabolites in body fluids. Advantages of saliva or sweat analysis are the ease of sample collection and that samples can be collected more frequently with much less stress on the patient. An alcohol biosensor has been developed with a hydrogen peroxide based electrode utilizing immobilized alcohol oxidase. Immobilization parameters have been optimized to increase the stability of the enzyme. An auter hydrophobic gas membrane was used to improve the selectivity of the probe. A hydrogen peroxide based amperometric biosensor has also been developed that utilized the enzyme glucose oxidase. The biosensor was applied to the determination of sera and saliva glucose content. Two hydrogen peroxide based amperometric biosensors that utilized lactate oxidase were also developed for determination of lactate in saliva and sweat. To discriminate against electroactive substances, the biosensor for assay of lactate in saliva utilized a dual electrode with one side active and one inactive, while the biosensor for assay of sweat lactate content utilized a hydrophobic hydrogen peroxide membrane to improve selectivity. Lactate content of saliva and sweat samples were measured after an intense physical exercise. A new procedure to measure glucose via transbuccal mucosa was developed using a dual glucose probe similar to that used for lactate. Correlation between glucose in blood and in transbuccal mucosa has been evaluated.
The novel approach of using a micro-sensor array of miniaturised solid-state ion-selective electrodes to analyse sweat samples for sodium, potassium and chloride simultaneously is described. The array, incorporated into a miniature flow cell which is linked to a portable PC for data acquisition, constitutes a small, portable, and simple to use analytical instrument. Samples are passed through the flow cell and over the array and an immediate potentiometric response is obtained, which can be equated to the concentrations of sodium, chloride, potassium and other parameters in the sweat sample. Used here in conjunction with a Wescor Macroduct sweat sampling unit, it promises a much simplified, much less expensive procedure for sweat analysis than the procedures currently in common use.
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.
OBJECTIVE: To obtain baseline data on the incidence of acute alcohol intoxication, chronic alcoholism and illicit drug usage among a cohort of injured patients. DESIGN: A prospective, descriptive study of 254 injured patients presenting at the trauma unit of Groote Schuur Hospital over an idealized week in 1997. Alcohol consumption was assessed by means of the Lion SD2 alcolmeter. Chronic alcoholism was assessed using the CAGE questionnaire. Each patient's urine was analysed for four drugs (cannabis, morphine, opiates and methaqualone) using conventional 'wet' analysis. Sweat was tested for cannabis using a Drugwipe. MAIN OUTCOME MEASURES: Socio-demographics, cause of injury, injury severity, acute alcohol intoxication, chronic alcohol usage and illicit drug involvement. RESULTS: Patients were predominantly male, coloured and an average of 31.3 years old. The majority had been injured as a result of interpersonal violence. Self-reported alcohol consumption was reliable but this was not so for self-reported drug usage. Sixty per cent of patients had positive alcohol levels on breath analysis. More than one-quarter of all the patients could be classified as chronic alcoholics on the CAGE questionnaire. On urine analysis, 40% of patients were found to have used at least one illicit drug in the recent past. The most commonly abused drugs were cannabis or a combination of cannabis and Mandrax, locally called a 'white pipe'. Use of the white pipe was confined almost exclusively to patients injured as a result of interpersonal violence. CONCLUSIONS: Alcohol remains the most commonly abused substance among trauma patients, but there are growing numbers of patients who simultaneously abuse illicit drugs. This study will be conducted annually to detect trends and identify emerging problems.
Male infertility as a result of isolated congenital bilateral absence of the vas deferens (CBAVD) is one primary genital form of cystic fibrosis (CF) and occurs in 1-2% of infertile men. Assisted fertilization in patients with CBAVD increases the risk of transmitting mutations in the CF gene. We developed a rational approach to genetic CF testing in infertile men. A total of 282 infertile male patients were screened for the most common CF mutations (DeltaF508, R117H, IVS8-5T). Clinical data including medical history, examination, semen analysis, sweat tests, karyotypes and hormonal values were analysed. We identified 23 patients carrying mutations in the CF gene (DeltaF508: 10 patients; R117H: six patients; IVS8-5T: 11 patients). Two patients were compound heterozygote for DeltaF508/R117H, two others for DeltaF508/IVS8-5T. Correlating these molecular analyses with the clinical data pertaining to serum follicle-stimulating hormone concentration, semen pH, sperm count and total testicular volume, we were able to develop a score with a high specificity (98.4) for the presence of a cystic fibrosis transmembrane conductance regulator (CFTR) mutation, but only with a low sensitivity (positive post-test likelihood: 62.5%; negative post-test likelihood: 6.3%). With regard to the low sensitivity and the high number of CFTR mutations found in this heterogeneous group of infertile men, we still recommend genetic CF testing before assisted fertilization.
Twenty-two patients with sweat gland carcinoma treated during the past 8 years are reported. They constitute 4.4% of malignant lesions of the skin during the same period. Of these 22 patients, 2 were apocrine gland carcinoma, 15 eccrine carcinoma, 4 hidradenocarcinoma and 1 cylindroma. In 11 patients with distant metastasis, 90.9% had lymphatic metastasis and 36.3% had blood metastasis. Vascular disseminations were mainly to the bone, lung and skin in order of incidence. Sweat gland carcinoma is rare and of low malignancy with evident tendency of recurrence. Prognosis was mainly related to the presence of distant metastasis. It is believed that the enlarged local resection should be given to patients without metastasis. On the other hand, local resection plus regional dissection should be performed on patients with metastasis. Post-operative irradiation may be helpful to prevent distant metastasis.
Sweat secretion involves the transport of salt and water into the lumen of the secretory coil of the sweat gland. By analogy to salivary and submucosal glands, where fluid secretion is aquaporin-5 (AQP5) dependent, we postulated that aquaporin water channels might facilitate sweat secretion. Immunolocalization with specific antibodies revealed strong expression of AQP5 at the luminal membrane of secretory epithelial cells in sweat glands in mouse paw skin. Novel quantitative methods were developed to compare sweat secretion in wild-type mice and mice lacking AQP5. Total hindpaw sweat secretion was measured by proton nuclear magnetic resonance of sweat-derived (1)H(2)O in (2)H(2)O solvent, and sweat secretion from individual glands was measured by real-time video imaging of sweat droplet formation under oil. Sweat secretion rates after pilocarpine stimulation did not differ in wild-type mice (0.21 +/- 0.03 nl min(-1) gland(-1)) vs. mice lacking AQP5 (0.19 +/- 0.04 nl min(-1) gland(-1)). The lack of effect of AQP5 on sweat secretion rate was confirmed by microcapillary collections of sweat from defined regions of mouse paws. Also, as by direct counting of droplets, the number of functional sweat glands was not affected by AQP5 deletion. Sweat gland morphology was similar in wild-type and AQP5 null mice. From sweat coil geometry and gland secretion rate, the rate of fluid secretion was estimated to be 130 nl min(-1) cm(-2) of secretory epithelium, substantially lower than that of > 500 nl min(-1) cm(-2) in kidney proximal tubules and salivary glands, where active fluid absorption or secretion is aquaporin dependent. These results indicate the expression of AQP5 in sweat gland secretory epithelium, but provide direct evidence against its physiological involvement in sweat fluid secretion in mice.
We compared concentrations of chloride and sulfate in sweat obtained by use of the Macroduct capillary-coil collection device with results obtained by the conventional absorbent filter pad technique. Samples obtained with the device weighed less than those obtained conventionally, but sweat chloride concentrations were not significantly different. To assess analysis of trace anions, we used inorganic sulfate as a prototype. Background contamination, a problem with the filter pads, was negligible with the Macroduct collector. However, with the Macroduct device, sulfate concentrations were nominally higher than with the conventional pads (105 +/- 6 vs 88 +/- 5 mumol/L) and showed no dependence of sulfate concentration on sweat rate. Subtraction of the significant "background" SO4 concentration obtained with blanks (i.e., unused filter pads) is a likely source of error in the conventional method. We consider the Macroduct device useful for study of trace constituents of human sweat.
The presence of high concentrations of sodium in the sweat of patients with cystic fibrosis is widely accepted by all investigators as one of the most important manifestations of the genetic defect. However, the simple means of sweat collection utilized for diagnostic purposes has been extended to the biochemical and physical analysis of the macromolecular components of human sweat. The most popular technique for the attainment of sweat has been collection of sweat droplets from the skin surface following heat stimulation. In this report, it is demonstrated that a far superior means of sweat collection exists based on a new collection device called the MACRODUCT. Utilizing this device, in conjunction with thin-layer isoelectric focusing, demonstrated that human sweat contains sex-specific proteins expressed in adult males and absent or greatly decreased from females and prepubertal males. Additionally, results are presented which suggest that the presence of epidermal keratins are an excellent marker for sweat contaminated with nonsweat gland-derived macromolecules.
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A modified method of analysis of sweat chloride concentration with an ion-selective electrode is presented. The original method of sweat chloride analysis proposed by the Orion Research Corporation (Cambridge, Massachusetts 02139) is inadequate because it produces erratic and misleading results. The modified method was compared with the reference quantitative method of Gibson and Cooke. In the modified method, individual electrode pads are cut and placed in the electrodes rather than using the pads supplied by the company; pilocarpine nitrate (2,000 mg/l) is used in place of pilocarpine HCl (640 mg/l); sodium bicarbonate as the weak electrolyte is used instead of K2SO4. A 10-minute period for sweat accumulation is employed rather than a zero-time collection as in the original Orion method. The modification has been studied for reproducibility in individuals, reproducibility between right and left arm in individuals; it has been compared extensively with the quantitative method of Gibson and Cooke, both in normal individuals and in patients with cystic fibrosis. There is excellent agreement between the modified method and the quantitative reference method. There appears to be a slight bias toward higher concentrations of chloride from the right arm compared with the left arm, but this difference is not medically significant.
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.
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Volumes of 10(-10) liter of sweat, saliva, and urine were analyzed with an energy-dispersive spectrometer (EDS) X-ray analyzer on a standard scanning electron microscope (SEM). Results of the EDS analysis of diluted and undiluted samples were verified by comparison with results of analyses of the same sample prepared by conventional quantitative methods. Except for Cl in concentrated urines and Mg in low concentrations, good agreement was found between the methods. The analysis provides quantitation of most elements of biological interest present in concentrations of about 1 mM, while it demonstrates good linearity (r greater than 0.99) throughout a wide range of commonly encountered biological concentrations. Reproducibility of the analysis is on the order of 2% and the minimal determinable concentration is generally between 0.5 and 1.0 mM for S, P, K, and Ca and slightly more than 1.0 mM for Mg.
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