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Experimental Physiology Apr 2021What is the central question of this study? What are the mechanisms by which equine sweat glands transport sodium, potassium and water into sweat? What is the main...
NEW FINDINGS
What is the central question of this study? What are the mechanisms by which equine sweat glands transport sodium, potassium and water into sweat? What is the main finding and its importance? The flux of sodium into sweat does not have an active transport component, the flux of potassium into sweat is partially dependent on an active transport mechanism, and there is no evidence for paracellular transport.
ABSTRACT
In two series of experiments, this study used radioactive sodium (Na ) and potassium (K ) to trace the net flux, and calculate the unidirectional fluxes, of these ions from extracellular fluid into sweat of horses during exercise and recovery. The effect of an oral electrolyte supplement (PNW) on the sweating responses and ion fluxes was also examined. Compared to 8 litres of water (controls), provision of 8 litres of PNW resulted in significantly increased sweating duration (P < 0.001). Two hours before exercise, Tc-labelled diethylene-triamine-pentaacetate (DTPA) was administered i.v. to determine if there was paracellular flux of this molecule in sweat glands during the period of sweating. One hour before beginning moderate-intensity exercise, horses were nasogastrically administered either Na (1-3 litres) or K (8 litres) with water (control) or an electrolyte supplement. Both radiotracers appeared in sweat within 10 min of exercise onset, and the sweat specific activity of both ions increased during exercise (P < 0.001), approaching plasma specific activities. There was no appearance of Tc-DTPA in sweat. The activities of Na and K, together with the concentrations Na , K and Cl , argued against significant paracellular flux of these ions into the lumen of sweat glands. The flux analysis for Na indicated a small intracellular pool within sweat gland cells, and no evidence for an active transport component. The flux analysis for K indicated a relatively large intracellular equilibration pool within sweat gland cells, with evidence for an active transport component. The results are discussed with respect to the current understanding of sweat gland epithelial cell ion transport mechanisms at both the basal and the apical membranes. It appears likely that the majority of ions appearing in sweat pass through sweat gland epithelial cells by transcellular mechanisms that include ion transporting pathways as well as apical vesicular exocytosis.
Topics: Animals; Chlorides; Horses; Physical Conditioning, Animal; Potassium; Sodium; Sweat; Sweating; Water
PubMed: 33550621
DOI: 10.1113/EP089232 -
American Journal of Physiology.... Jan 2012Appropriate quantification of analytical and biological variation of thermoregulatory sweating has important practical utility for research design and statistical...
Appropriate quantification of analytical and biological variation of thermoregulatory sweating has important practical utility for research design and statistical analysis. We sought to examine contributors to variability in local forearm sweating rate (SR) and sweating onset (SO) and to evaluate the potential for using bilateral measurements. Two women and eight men (26 ± 9 yr; 79 ± 12 kg) completed 5 days of heat acclimation and walked (1.8 l/min VO(2)) on three occasions for 30 min in 40°C, 20% RH, while local SR and SO were measured. Local SR measures among days were not different (2.14 ± 0.72 vs. 2.02 ± 0.79 vs. 2.31 ± 0.72 mg·cm(2)·min(-1), P = 0.19) nor was SO (10.47 ± 2.54 vs. 10.04 ± 2.97 vs. 9.87 ± 3.44 min P = 0.82). Bilateral SR (2.14 ± 0.72 vs. 2.16 ± 0.71 mg·cm(2)·min(-1), P = 0.56) and SO (10.47 ± 2.54 vs. 10.83 ± 2.48 min, P = 0.09) were similar and differences were ≤ 1 SD of day-to-day differences for a single forearm. Analytical imprecision (CV(a)), within (CV(i))-, and between (CV(g))-subjects' coefficient of variation for local SR were 2.4%, 22.3%, and 56.4%, respectively, and were 0%, 9.6%, and 41%, respectively, for SO. We conclude: 1) technologically, sweat capsules contribute negligibly to sweat measurement variation; 2) bilateral measures of SR and SO appear interchangeable; 3) when studying potential factors affecting sweating, changes in SO afford a more favorable signal-to-noise ratio vs. changes in SR. These findings provide a quantitative basis for study design and optimization of power/sample size analysis in the evaluation of thermoregulatory sweating.
Topics: Acclimatization; Adult; Body Temperature; Body Temperature Regulation; Exercise; Female; Humans; Male; Oxygen Consumption; Regional Blood Flow; Research Design; Stress, Physiological; Sweating
PubMed: 22071159
DOI: 10.1152/ajpregu.00456.2011 -
Acta Dermato-venereologica Jan 2020Infectious pseudochromhidrosis is a rare dermatological disorder, characterized by a change in colour of the sweat from normal skin, caused by pigments from... (Review)
Review
Infectious pseudochromhidrosis is a rare dermatological disorder, characterized by a change in colour of the sweat from normal skin, caused by pigments from microorganisms. Such pigments are a result of evolutionary competition among microorganisms, which appears to be a decisive factor in their survival, patho-genicity, and virulence. Four bacteria are known to be involved in infectious pseudochromhidrosis: Bacillus spp. (blue colour), Corynebacterium spp. (brown/black colour), Serratia marcescens (red/pink colour), and Pseudomonas aeruginosa (blue-green colour). Infectious pseudochromhidrosis seems to be triggered by certain drugs and conditions causing physiological alterations and/or changes in microflora on the skin surface. The condition can be treated by addressing potential triggers and/or prescribing antibiotic/antiseptic therapies. We report here a case of blue infectious pseudochromhidrosis caused by pigment-producing Bacillus cereus and the results of a literature review.
Topics: Adult; Color; Female; Humans; Sweat Gland Diseases; Sweating; Young Adult
PubMed: 31612235
DOI: 10.2340/00015555-3338 -
American Journal of Physiology.... Oct 2013Aging is associated with attenuated thermoregulatory function that varies regionally over the body. Decrements in vasodilation and sweating are well documented with age,...
Aging is associated with attenuated thermoregulatory function that varies regionally over the body. Decrements in vasodilation and sweating are well documented with age, yet limited data are available concerning the regional relation between these responses. We aimed to examine age-related alterations in the relation between regional sweating (RSR) and skin blood flow (SkBF) to thermal and pharmacological stimuli. Four microdialysis fibers were inserted in the ventral forearm, abdomen, thigh, and lower back of eight healthy aged subjects (64 ± 7 yr) and nine young (23 ± 3 yr) during 1) ACh dose response (1 × 10(-7) to 0.1 M, mean skin temperature 34°C) and 2) passive whole body heating to Δ1°C rise in oral temperature (Tor). RSR and SkBF were measured over each microdialysis membrane using ventilated capsules and laser-Doppler flowmetry. Maximal SkBF was measured at the end of both protocols (50 mM SNP). Regional sweating thresholds and RSR were attenuated in aged vs. young at all sites (P < 0.0001) during whole body heating. Vasodilation thresholds were similar between groups (P > 0.05). Attenuated SkBF were observed at the arm and back in the aged, representing 56 and 82% of those in the young at these sites, respectively (0.5 ΔTor). During ACh perfusion, SkBF (P = 0.137) and RSR were similar between groups (P = 0.326). Together these findings suggest regional age-related decrements in heat-activated sweat gland function but not cholinergic sensitivity. Functional consequences of such thermoregulatory impairment include the compromised ability of older individuals to defend core temperature during heat exposure and a subsequently greater susceptibility to heat-related illness and injury.
Topics: Acetylcholine; Adult; Age Factors; Aged; Aging; Blood Pressure; Body Temperature Regulation; Female; Hemodynamics; Hot Temperature; Humans; Male; Middle Aged; Regional Blood Flow; Skin; Skin Temperature; Sweating; Vasodilation; Vasodilator Agents
PubMed: 23926135
DOI: 10.1152/ajpregu.00290.2013 -
The Journal of Physiology Feb 2016A post-menopausal hot flush consists of profuse physiological elevations in cutaneous vasodilatation and sweating that are accompanied by reduced brain blood flow. These...
A post-menopausal hot flush consists of profuse physiological elevations in cutaneous vasodilatation and sweating that are accompanied by reduced brain blood flow. These responses can be used to objectively quantify hot flush severity. The impact of an exercise training intervention on the physiological responses occurring during a hot flush is currently unknown. In a preference-controlled trial involving 21 post-menopausal women, 16 weeks of supervised moderate intensity exercise training was found to improve cardiorespiratory fitness and attenuate cutaneous vasodilatation, sweating and the reductions in cerebral blood flow during a hot flush. It is concluded that the improvements in fitness that are mediated by 16 weeks of exercise training reduce the severity of physiological symptoms that occur during a post-menopausal hot flush. A hot flush is characterised by feelings of intense heat, profuse elevations in cutaneous vasodilatation and sweating, and reduced brain blood flow. Exercise training reduces self-reported hot flush severity, but underpinning physiological data are lacking. We hypothesised that exercise training attenuates the changes in cutaneous vasodilatation, sweat rate and cerebral blood flow during a hot flush. In a preference trial, 18 symptomatic post-menopausal women underwent a passive heat stress to induce hot flushes at baseline and follow-up. Fourteen participants opted for a 16 week moderate intensity supervised exercise intervention, while seven participants opted for control. Sweat rate, cutaneous vasodilatation, blood pressure, heart rate and middle cerebral artery velocity (MCAv) were measured during the hot flushes. Data were binned into eight equal segments, each representing 12.5% of hot flush duration. Weekly self-reported frequency and severity of hot flushes were also recorded at baseline and follow-up. Following training, mean hot flush sweat rate decreased by 0.04 mg cm(2) min(-1) at the chest (95% confidence interval 0.02-0.06, P = 0.01) and by 0.03 mg cm(2) min(-1) (0.02-0.05, P = 0.03) at the forearm, compared with negligible changes in control. Training also mediated reductions in cutaneous vasodilatation by 9% (6-12%) at the chest and by 7% (4-9%) at forearm (P ≤ 0.05). Training attenuated hot flush MCAv by 3.4 cm s(-1) (0.7-5.1 cm s(-1) , P = 0.04) compared with negligible changes in control. Exercise training reduced the self-reported severity of hot flushes by 109 arbitrary units (80-121, P < 0.001). These data indicate that exercise training leads to parallel reductions in hot flush severity and within-flush changes in cutaneous vasodilatation, sweating and cerebral blood flow.
Topics: Blood Pressure; Cerebrovascular Circulation; Exercise; Exercise Therapy; Female; Heart Rate; Hot Flashes; Humans; Skin; Sweating; Vasodilation
PubMed: 26676059
DOI: 10.1113/JP271456 -
Arquivos de Neuro-psiquiatria Oct 2016Neurofibromatosis type 1 (NF1) causes neural and cutaneous disorders and reduced exercise capacity. Exercise/heat exposure increasing internal temperature must be...
OBJECTIVE
Neurofibromatosis type 1 (NF1) causes neural and cutaneous disorders and reduced exercise capacity. Exercise/heat exposure increasing internal temperature must be compensated by eccrine sweat function and warmed skin vasodilation. We suspected NF1 could adversely affect eccrine sweat function and/or vascular thermoregulatory responses (VTR).
METHODS
The eccrine sweat function and VTR of 25 NF1 volunteers (14 males, 11 females; 16-57 years old) were compared with 23 non-NF1 controls matched by sex, age, height and weight (CG). Sweating was induced by 1) pilocarpine 1% iontophoresis (PILO); and 2) by passive heating (HEAT) via the lower third of the legs being immersed in 42°C water for one hour. Previously established eccrine sweat function and VTR protocols were used.
RESULTS
The NF1 group showed: a) lower sweat rate than the CG group during PILO; b) a smaller diastolic pressure decrease; and c) higher tympanic temperatures than controls during HEAT (p < 0.05).
CONCLUSION
Reduced sweating and vascular thermoregulatory responses suggest autonomic dysfunction in NF1 individuals.
Topics: Adolescent; Adult; Age Factors; Analysis of Variance; Body Temperature Regulation; Case-Control Studies; Female; Humans; Male; Middle Aged; Neurofibromatosis 1; Primary Dysautonomias; Reference Values; Sex Factors; Skin; Sweat; Sweating; Time Factors; Young Adult
PubMed: 27759804
DOI: 10.1590/0004-282X20160122 -
Skin Research and Technology : Official... Jan 2019Recent increases in the use of noninvasive matrices for biomedical analysis has led to interest in the evaluation of sweat for both clinical and research applications.... (Review)
Review
BACKGROUND AND OBJECTIVE
Recent increases in the use of noninvasive matrices for biomedical analysis has led to interest in the evaluation of sweat for both clinical and research applications. However, despite being one of the two main cutaneous secretions, until very recently, only one study actually analyzed sweat in the context of cutaneous disease. This review attempts to make the case for increased use of sweat in cutaneous research, and discusses lipid mediators as potential analytical targets in sweat.
METHODS
Sweat composition and its relationship with the skin and systemic circulation are discussed, as are practical considerations for sweat sampling and analysis. Previous analyses of lipid mediators in skin biopsies are provided to show that lipid mediators can regulate cutaneous processes and disease pathways. Summaries of recent studies involving the analysis of sweat lipid mediators are provided to demonstrate the utility of sweat lipid mediator testing to support future cutaneous research studies.
RESULTS
Sweat has the potential to reflect both local and systemic biochemical changes in response to disease or intervention, and two recent studies of sweat lipid mediators confirm this ability. Additionally, sweat lipid mediators appear to be temporally stable with individual variability comparable to other matrices, suggesting that these analytes could be useful biomarkers.
CONCLUSIONS
Sweat metabolites may be capable of reporting changes in cutaneous biochemical pathways, thereby providing insight into the immunomodulatory biochemistry of the skin. Lipid mediator analysis of sweat appears to be a non invasive approach that could enhance existing cutaneous research and diagnostic methodologies.
Topics: Fatty Acids; Humans; Lipids; Metabolomics; Skin Diseases; Specimen Handling; Sweat
PubMed: 30030941
DOI: 10.1111/srt.12617 -
Philosophical Transactions of the Royal... Jun 2020Humans, like other animals, have an excellent sense of smell that can serve social communication. Although ample research has shown that body odours can convey transient...
Humans, like other animals, have an excellent sense of smell that can serve social communication. Although ample research has shown that body odours can convey transient emotions like fear, these studies have exclusively treated emotions as , neglecting the question whether emotion can be expressed chemically. Using a unique combination of methods and techniques, we explored a dose-response function: Can fear intensity be in fear sweat? Specifically, fear experience was quantified using multivariate pattern classification (combining physiological data and subjective feelings with partial least-squares-discriminant analysis), whereas a photo-ionization detector quantified volatile molecules in sweat. Thirty-six male participants donated sweat while watching scary film clips and control (calming) film clips. Both traditional univariate and novel multivariate analysis (100% classification accuracy; : 0.76; : 0.79) underlined effective fear induction. Using their regression-weighted scores, participants were assigned significantly above chance (83% > 33%) to fear intensity categories (low-medium-high). Notably, the high fear group ( = 12) produced higher doses of armpit sweat, and greater doses of fear sweat emitted more volatile molecules ( = 3). This study brings new evidence to show that fear intensity is encoded in sweat (dose-response function), opening a field that examines intensity coding and decoding of other chemically communicable states/traits. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.
Topics: Adult; Axilla; Fear; Humans; Male; Nonverbal Communication; Odorants; Olfactory Perception; Photic Stimulation; Smell; Sweat; Young Adult
PubMed: 32306883
DOI: 10.1098/rstb.2019.0271 -
The Cochrane Database of Systematic... Dec 2013Vasomotor symptoms, such as hot flushes and night sweats, are very common during the menopausal transition. Hormone therapy has traditionally been used as a highly... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Vasomotor symptoms, such as hot flushes and night sweats, are very common during the menopausal transition. Hormone therapy has traditionally been used as a highly effective treatment, but concerns about increased risk of some chronic diseases have markedly increased the interest of women in alternative treatments. Some of the most popular of these treatments are foods or supplements enriched with phytoestrogens-plant-derived chemicals that have estrogenic action.
OBJECTIVES
To assess the efficacy, safety and acceptability of food products, extracts and dietary supplements containing high levels of phytoestrogens when compared with no treatment, placebo or hormone therapy for the amelioration of vasomotor menopausal symptoms (such as hot flushes and night sweats) in perimenopausal and postmenopausal women.
SEARCH METHODS
Searches targeted the following electronic databases: the Cochrane Menstrual Disorders and Subfertility Group Specialised Register of randomised trials (29 July 2013), the Cochrane Register of Controlled Trials (CENTRAL; 29 July 2013), MEDLINE (inception to 29 July 2013), EMBASE (inception to 29 July 2013), AMED (1985 to 29 July 2013), PsycINFO (inception to 29 July 2013) and CINAHL (inception to 29 July 2013). Attempts were made to access grey literature by sending letters to pharmaceutical companies and performing searches of ongoing trial registers. Reference lists of included trials were also searched.
SELECTION CRITERIA
Studies were included if they were randomised, included perimenopausal or postmenopausal participants with vasomotor symptoms (hot flushes or night sweats), lasted at least 12 weeks and provided interventions such as foods or supplements with high levels of phytoestrogens (not combined with other herbal treatments). Trials that included women who had breast cancer or a history of breast cancer were excluded.
DATA COLLECTION AND ANALYSIS
Selection of trials, extraction of data and assessment of quality were undertaken by at least two review authors. Most trials were too dissimilar for their results to be combined in a meta-analysis, so these findings are provided in narrative 'Summary of results' tables. Studies were grouped into broad categories: dietary soy, soy extracts, red clover extracts, genistein extracts and other types of phytoestrogens. Five trials used Promensil, a red clover extract; results of these trials were combined in a meta-analysis, and summary effect measures were calculated.
MAIN RESULTS
A total of 43 randomised controlled trials (4,364 participants) were included in this review. Very few trials provided data suitable for inclusion in a meta-analysis. Among the five trials that yielded data assessing the daily frequency of hot flushes suitable for pooling, no significant difference overall was noted in the incidence of hot flushes between participants taking Promensil (a red clover extract) and those given placebo (mean difference (MD) -0.93, 95% confidence interval (CI) -1.95 to 0.10, I(2) = 31%). No evidence indicated a difference in percentage reduction in hot flushes in two trials between Promensil and placebo (MD 20.15, 95% CI -12.08 to 52.38, I(2) = 82%). Four trials that were not combined in meta-analyses suggested that extracts with high (> 30 mg/d) levels of genistein consistently reduced the frequency of hot flushes. Individual results from the remaining trials were compared in broad subgroups such as dietary soy, soy extracts and other types of phytoestrogens that could not be combined. Some of these trials found that phytoestrogen treatments alleviated the frequency and severity of hot flushes and night sweats when compared with placebo, but many trials were small and were determined to be at high risk of bias. A strong placebo effect was noted in most trials, with a reduction in frequency ranging from 1% to 59% with placebo. No indication suggested that discrepant results were due to the amount of isoflavone in the active treatment arm, the severity of vasomotor symptoms or trial quality factors. Also, no evidence indicated that these treatments caused oestrogenic stimulation of the endometrium or the vagina or other adverse effects when used for up to two years.
AUTHORS' CONCLUSIONS
No conclusive evidence shows that phytoestrogen supplements effectively reduce the frequency or severity of hot flushes and night sweats in perimenopausal or postmenopausal women, although benefits derived from concentrates of genistein should be further investigated.
Topics: Female; Hot Flashes; Humans; Isoflavones; Phytoestrogens; Randomized Controlled Trials as Topic; Glycine max; Sweating; Trifolium
PubMed: 24323914
DOI: 10.1002/14651858.CD001395.pub4 -
Blood Feb 2013
Topics: Adolescent; Female; Hemorrhage; Humans; Skin Diseases; Sweat; Sweat Gland Diseases; Sweating
PubMed: 23570065
DOI: 10.1182/blood-2012-09-450031