RESUMEN
Hyperhidrosis (HH) is a chronic disorder of excess sweat production that may have a significant adverse effect on quality of life. A variety of treatment modalities currently exist to manage HH. Initial treatment includes lifestyle and behavioral recommendations. Antiperspirants are regarded as the first-line therapy for primary focal HH and can provide significant benefit. Iontophoresis is the primary remedy for palmar and plantar HH. Botulinum toxin injections are administered at the dermal-subcutaneous junction and serve as a safe and effective treatment option for focal HH. Oral systemic agents are reserved for treatment-resistant cases or for generalized HH. Energy-delivering devices such as lasers, ultrasound technology, microwave thermolysis, and fractional microneedle radiofrequency may also be utilized to reduce focal sweating. Surgery may be considered when more conservative treatments have failed. Local surgical techniques, particularly for axillary HH, include excision, curettage, liposuction, or a combination of these techniques. Sympathectomy is the treatment of last resort when conservative treatments are unsuccessful or intolerable, and after accepting secondary compensatory HH as a potential complication. A review of treatment modalities for HH and a sequenced approach are presented.
Asunto(s)
Hiperhidrosis/terapia , Calidad de Vida , Glándulas Sudoríparas/cirugía , Administración Cutánea , Antitranspirantes/uso terapéutico , Toxinas Botulínicas Tipo A/administración & dosificación , Antagonistas Colinérgicos/administración & dosificación , Terapia Cognitivo-Conductual , Terapia Combinada/métodos , Legrado , Humanos , Hiperhidrosis/etiología , Hiperhidrosis/psicología , Inyecciones Subcutáneas , Iontoforesis , Microondas/uso terapéutico , Ablación por Radiofrecuencia , Glándulas Sudoríparas/fisiopatología , Glándulas Sudoríparas/efectos de la radiación , Sudoración/fisiología , Sudoración/efectos de la radiación , Simpatectomía , Resultado del Tratamiento , Terapia por UltrasonidoRESUMEN
BACKGROUND: Minimally invasive techniques, including superficial liposuction with automatic shaver curettage (LC), subcutaneous laser treatment, and microwave-based therapy have been developed to treat osmidrosis. Few studies have compared these three techniques in relation to clinical efficacy, life quality improvement, and downtime. AIMS: We aim to evaluate clinical results and life quality improvement, in addition to downtime and complications, between these three techniques. PATIENTS/METHODS: Clinical records of patients treated with these three minimally invasive techniques for axillary osmidrosis were retrospectively reviewed. Hyperhidrosis disease severity scale, Dermatology Life of Quality Index, clinical improvement, complication, and recurrence were assessed. RESULTS: Among 403 patients, 168 received microwave-based therapy, 119 received subcutaneous laser treatment, and 116 received LC. All treatments showed significant improvements (P < 0.001) in HDSS, DLQI and clinical result after 3 and 12 months comparing to the baseline. But the improvements of subcutaneous laser were significantly inferior to microwave-base therapy and LC. Patients who received LC had a significantly longer downtime (P < 0.001) than those who received other treatments. The recurrence rate was significantly higher in the subcutaneous laser treatment group, and the microwave-based therapy group exhibited a longer recurrence duration (P < 0.001). LC group presented higher complication rate than other treatments. CONCLUSION: Comparing to other treatments, microwave-based therapy was effective in treating osmidrosis with minimal downtime, recurrence, and complications. It could be a durable and effective therapeutic modality for osmidrosis and is less operator-dependent. It may be considered as a first-line treatment for axillary osmidrosis.
Asunto(s)
Legrado/métodos , Hiperhidrosis/terapia , Terapia por Láser/métodos , Lipectomía/métodos , Microondas/uso terapéutico , Adulto , Glándulas Apocrinas/efectos de la radiación , Glándulas Apocrinas/cirugía , Axila , Legrado/efectos adversos , Legrado/instrumentación , Femenino , Estudios de Seguimiento , Humanos , Hiperhidrosis/diagnóstico , Hiperhidrosis/psicología , Terapia por Láser/efectos adversos , Terapia por Láser/instrumentación , Láseres de Estado Sólido/efectos adversos , Láseres de Estado Sólido/uso terapéutico , Lipectomía/efectos adversos , Lipectomía/instrumentación , Masculino , Microondas/efectos adversos , Odorantes , Dolor Postoperatorio/epidemiología , Dolor Postoperatorio/etiología , Satisfacción del Paciente , Calidad de Vida , Recurrencia , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Sudoración/efectos de la radiación , Factores de Tiempo , Resultado del Tratamiento , Adulto JovenRESUMEN
Axillary hyperhidrosis (AH) and bromhidrosis are common causes of consultation in dermatology. Currently, the most widely prescribed treatment for AH is botulinum toxin, a very effective but temporary option; it is totally ineffective in bromhidrosis. Sympathectomy is an increasingly infrequent choice of treatment due to the high incidence of compensatory hyperhidrosis. We describe the treatment of AH and bromhidrosis with a novel microwave device that can fibrose eccrine and apocrine glands, achieving possibly permanent results. The procedure should preferably be performed under tumescent anesthesia. Side effects, principally local inflammation, are transient. Clinical effectiveness and safety, supported by recently published studies, position this technique as a first-choice option both for hyperhidrosis and for bromhidrosis.
Asunto(s)
Diatermia/métodos , Hiperhidrosis/terapia , Microondas/uso terapéutico , Glándulas Sudoríparas/efectos de la radiación , Anestesia Local/métodos , Diatermia/efectos adversos , Diatermia/economía , Diatermia/instrumentación , Fibrosis , Humanos , Estudios Multicéntricos como Asunto , Odorantes , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Retrospectivos , Glándulas Sudoríparas/patología , Sudoración/efectos de la radiación , Resultado del TratamientoRESUMEN
BACKGROUND: Removing unwanted body hair is a growing trend in society today, and there are many laser-based devices for hair reduction. There are some limitations to those methods, including the lack of efficacy for lighter color hair. OBJECTIVE: The objective was to quantify hair reduction in the axillae after treatment with a noninvasive microwave energy device. MATERIALS AND METHODS: A prospective, multicenter study was performed at 3 private dermatology clinics. Fifty-six adult subjects seeking axillary hair reduction were enrolled and treated with the device in 1 or 2 treatment sessions 3 months apart at various energy levels, and followed for 12 months. The primary analysis was monitoring reduction of hair counts from baseline to follow-up visits. A subject assessment of overall satisfaction, odor ratings, and sweat reduction ratings was provided at follow-up visits. RESULTS: Fifty-six subjects received treatment, with an average total underarm hair reduction of approximately 70% for both light and dark hair. Percentage of patients with hair reduction of 30% or more was significantly higher than 50% at all follow-up visits. Half of treated subjects reported expected mild transient post-treatment effects such as localized edema, discomfort, and bruising. Other reported events were mild. CONCLUSION: This clinical study provides evidence for safe and permanent axillary hair reduction, showing stable average reduction that lasted through the year of follow-up. Most notably, the study has shown the treatment's efficacy for reduction of light-colored axillary hair.
Asunto(s)
Remoción del Cabello/métodos , Hiperhidrosis/radioterapia , Microondas/uso terapéutico , Adolescente , Adulto , Axila , Femenino , Estudios de Seguimiento , Cabello/efectos de la radiación , Color del Cabello , Humanos , Masculino , Microondas/efectos adversos , Persona de Mediana Edad , Odorantes , Satisfacción del Paciente , Fotograbar , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Método Simple Ciego , Sudoración/efectos de la radiación , Adulto JovenRESUMEN
A microwave-based device has been developed to treat axillary hyperhidrosis by selectively heating the interface between the skin and underlying fat in the axilla. This study was conducted to evaluate the efficacy and safety of microwave-based devices for axillary hyperhidrosis and osmidrosis in Asians. Eleven patients (8 females and 3 males, age range 20-52 years, mean age 37.6 years) with axillary hyperhidrosis or osmidrosis were enrolled, treated with the microwave-based device, and followed up for 7 months. Procedure efficacy, patient satisfaction, and treatment safety were assessed. The clinical records were reviewed and the patients were interviewed individually at follow-up visits or via telephone. Evaluation of sweating showed at least a 2-point drop or greater in hyperhidrosis disease severity scale (HDSS) in 83.3% subjects (10/12 axillae) as measured at the 7-month follow-up. Of 16 axillae with osmidrosis, 93.8% (15/16 axillae) showed good to excellent results. Histologic findings also showed destruction of eccrine and apocrine glands that were replaced with fibrosis. Regarding safety, altered sensation of arms developed in one case that resolved after 3 months. This novel microwave-based treatment appears to be effective and well tolerated for the treatment of axillary hyperhidrosis and osmidrosis in Asians.
Asunto(s)
Hiperhidrosis/radioterapia , Microondas/uso terapéutico , Odorantes/prevención & control , Sudoración/efectos de la radiación , Adulto , Glándulas Apocrinas/patología , Glándulas Apocrinas/efectos de la radiación , Pueblo Asiatico , Axila , Glándulas Ecrinas/patología , Glándulas Ecrinas/efectos de la radiación , Femenino , Humanos , Hiperhidrosis/patología , Masculino , Microondas/efectos adversos , Persona de Mediana Edad , Satisfacción del Paciente , Índice de Severidad de la Enfermedad , Resultado del Tratamiento , Adulto JovenRESUMEN
BACKGROUND: This study tested the hypothesis that the core interthreshold zone (CIZ) changes during exposure to red or blue light via the non-visual pathway, because it is known that light intensity affects the central nervous system. We conducted a series of human experiments with 5 or 10 male subjects in each experiment. METHODS: The air temperature in the climatic chamber was maintained at 20 to 24°C. The subjects wore suits perfused with 25°C water at a rate of 600 cm3/min. They exercised on an ergometer at 50% of their maximum work rate for 10 to 15 minutes until sweating commenced, and then remained continuously seated without exercise until their oxygen uptake increased. The rectal temperature and skin temperatures at four sites were monitored using thermistors. The sweating rate was measured at the forehead with a sweat rate monitor. Oxygen uptake was monitored with a gas analyzer. The subjects were exposed to red or blue light at 500 lx and 1000 lx in both summer and winter. RESULTS: The mean CIZs at 500 lx were 0.23 ± 0.16°C under red light and 0.20 ± 0.10°C under blue light in the summer, and 0.19 ± 0.20°C under red light and 0.26 ± 0.24°C under blue light in the winter. The CIZs at 1000 lx were 0.18 ± 0.14°C under red light and 0.15 ± 0.20°C under blue light in the summer, and 0.52 ± 0.18°C under red light and 0.71 ± 0.28°C under blue light in the winter. A significant difference (P <0.05) was observed in the CIZs between red and blue light at 1000 lx in the winter, and significant seasonal differences under red light (P <0.05) and blue light (P <0.01) were also observed at 1000 lx. CONCLUSIONS: The present study demonstrated that dynamic changes in the physiological effects of colors of light on autonomic functions via the non-visual pathway may be associated with the temperature regulation system.
Asunto(s)
Temperatura Corporal/efectos de la radiación , Tiritona/efectos de la radiación , Sudoración/efectos de la radiación , Adulto , Humanos , Luz , Masculino , Estaciones del Año , Adulto JovenRESUMEN
Human exposure to radio frequency (RF) electromagnetic energy is known to result in tissue heating and can raise temperatures substantially in some situations. Standards for safe exposure to RF do not reflect bio-heat transfer considerations however. Thermoregulatory function (vasodilation, sweating) may mitigate RF heating effects in some environments and exposure scenarios. Conversely, a combination of an extreme environment (high temperature, high humidity), high activity levels and thermally insulating garments may exacerbate RF exposure and pose a risk of unsafe temperature elevation, even for power densities which might be acceptable in a normothermic environment. A high-resolution thermophysiological model, incorporating a heterogeneous tissue model of a seated adult has been developed and used to replicate a series of whole-body exposures at a frequency (100 MHz) which approximates that of human whole-body resonance. Exposures were simulated at three power densities (4, 6 and 8 mW cm(-2)) plus a sham exposure and at three different ambient temperatures (24, 28 and 31 °C). The maximum hypothalamic temperature increase over the course of a 45 min exposure was 0.28 °C and occurred in the most extreme conditions (T(AMB) = 31 °C, PD = 8 mW cm(-2)). Skin temperature increases attributable to RF exposure were modest, with the exception of a 'hot spot' in the vicinity of the ankle where skin temperatures exceeded 39 °C. Temperature increases in internal organs and tissues were small, except for connective tissue and bone in the lower leg and foot. Temperature elevation also was noted in the spinal cord, consistent with a hot spot previously identified in the literature.
Asunto(s)
Exposición a Riesgos Ambientales/efectos adversos , Modelos Anatómicos , Ondas de Radio/efectos adversos , Temperatura , Adulto , Humanos , Temperatura Cutánea/efectos de la radiación , Sudoración/efectos de la radiación , Factores de TiempoRESUMEN
BACKGROUND: A third-generation microwave-based device has been developed to treat axillary hyperhidrosis by selectively heating the interface between the skin and underlying fat where the sweat glands reside. MATERIALS AND METHODS: Thirty-one (31) adults with primary axillary hyperhidrosis were enrolled. All subjects had one to three procedure sessions over a 6-month period to treat both axillae fully. Efficacy was assessed using the Hyperhidrosis Disease Severity Scale (HDSS), gravimetric weight of sweat, and the Dermatologic Life Quality Index (DLQI), a dermatology-specific quality-of-life scale. Subject safety was assessed at each visit. Subjects were followed for 12 months after all procedure sessions were complete. RESULTS: At the 12-month follow-up visit, 90.3% had HDSS scores of 1 or 2, 90.3% had at least a 50% reduction in axillary sweat from baseline, and 85.2% had a reduction of at least 5 points on the DLQI. All subjects experienced transient effects in the treatment area such as swelling, discomfort, and numbness. The most common adverse event (12 subjects) was the presence of altered sensation in the skin of the arm that resolved in all subjects. CONCLUSION: The device tested provided efficacious and durable treatment for axillary hyperhidrosis.
Asunto(s)
Axila , Hiperhidrosis/radioterapia , Microondas/uso terapéutico , Sudoración/efectos de la radiación , Adolescente , Adulto , Anciano , Femenino , Humanos , Hiperhidrosis/fisiopatología , Masculino , Persona de Mediana Edad , Calidad de Vida , Resultado del TratamientoRESUMEN
BACKGROUND: Duration of effect and effectiveness limit current options for treating axillary hyperhidrosis. A new microwave procedure for treatment of axillary hyperhidrosis has been tested. STUDY DESIGN/MATERIALS AND METHODS: Adults with primary axillary hyperhidrosis were enrolled in a randomized, sham-controlled, blinded study. Subjects were required to have a Hyperhidrosis Disease Severity Scale (HDSS) score of 3 or 4 and baseline sweat production greater than 50 mg/5 min. Procedures were administered using a proprietary microwave energy device that isolates and heats target tissue. Responders were defined as subjects reporting a HDSS score of 1 or 2. Subjects were followed for 6 months (sham group) or 12 months (active group). RESULTS: Thirty days after treatment, the active group had a responder rate of 89% (72/81), and the sham group had a responder rate of 54% (21/39) (P < .001). Treatment efficacy was stable from 3 months (74%) to 12 months (69%), when follow-up ended. Adverse events were generally mild, and all but one resolved over time. CONCLUSIONS: The procedure demonstrated statistically significant, long-term efficacy in sweat reduction. As with any new procedure, findings from this first investigational device study identified optimization strategies for the future.
Asunto(s)
Hiperhidrosis/radioterapia , Microondas/uso terapéutico , Sudoración/efectos de la radiación , Adulto , Axila , Método Doble Ciego , Femenino , Humanos , Hiperhidrosis/fisiopatología , Masculino , Microondas/efectos adversos , Persona de Mediana EdadRESUMEN
We investigated the validity of employing a fuzzy piecewise prediction equation (PW) [Gonzalez et al. J Appl Physiol 107: 379-388, 2009] defined by sweat rate (m(sw), g·m(-2)·h(-1)) = 147 + 1.527·(E(req)) - 0.87·(E(max)), which integrates evaporation required (E(req)) and the maximum evaporative capacity of the environment (E(max)). Heat exchange and physiological responses were determined throughout the trials. Environmental conditions were ambient temperature (T(a)) = 16-26°C, relative humidity (RH) = 51-55%, and wind speed (V) = 0.5-1.5 m/s. Volunteers wore military fatigues [clothing evaporative potential (i(m)/clo) = 0.33] and carried loads (15-31 kg) while marching 14-37 km over variable terrains either at night (N = 77, trials 1-5) or night with increasing daylight (N = 33, trials 6 and 7). PW was modified (Pw,sol) for transient solar radiation (R(sol), W) determined from measured solar loads and verified in trials 6 and 7. PW provided a valid m(sw) prediction during night trials (1-5) matching previous laboratory values and verified by bootstrap correlation (r(bs) of 0.81, SE ± 0.014, SEE = ± 69.2 g·m(-2)·h(-1)). For trials 6 and 7, E(req) and E(max) components included R(sol) applying a modified equation Pw,sol, in which m(sw) = 147 + 1.527·(E(req,sol)) - 0.87·(E(max)). Linear prediction of m(sw) = 0.72·Pw,sol + 135 (N = 33) was validated (R(2) = 0.92; SEE = ±33.8 g·m(-2)·h(-1)) with PW ß-coefficients unaltered during field marches between 16°C and 26°C T(a) for m(sw) ≤ 700 g·m(-2)·h(-1). PW was additionally derived for cool laboratory/night conditions (T(a) < 20°C) in which E(req) is low but E(max) is high, as: PW,cool (g·m(-2)·h(-1)) = 350 + 1.527·E(req) - 0.87·E(max). These sweat prediction equations allow valid tools for civilian, sports, and military medicine communities to predict water needs during a variety of heat stress/exercise conditions.
Asunto(s)
Ejercicio Físico/fisiología , Modelos Biológicos , Luz Solar , Sudoración/fisiología , Sudoración/efectos de la radiación , Rayos Ultravioleta , Vestuario , Ambiente , Humanos , Humedad , Masculino , Reproducibilidad de los Resultados , Temperatura , Factores de Tiempo , VientoRESUMEN
The purpose of this study was to assess the effects of artificial shade, tree shade, and no shade on physiological changes, oxidative stress, and total antioxidant power in Thai Brahman cattle. Twenty-one cattle were divided into three groups: cattle maintained under artificial shade, under tree shade, and without shade. On days 1, 7, 14, 21, and 28 of the experimental period, after the cattle were set in individual stalls for 2 h, physiological changes, thiobarbituric acid reactive substances (TBARS), and total antioxidant power were investigated. The results revealed that the respiratory rate, heart rate, sweat rate and the neutrophil/lymphocyte ratio of the no-shade cattle were significantly higher than those of cattle maintained under artificial shade and tree shade (P < 0.05). During the early period of heat exposure, the total antioxidant power of the no-shade cattle was lower than those of cattle maintained under artificial shade and tree shade, but the total antioxidant power of cattle maintained under artificial shade and tree shade were not different (P > 0.05). However, rectal temperature and packed cell volume of the cattle in all groups did not differ (P > 0.05). These results showed that artificial shade and tree shade can protect cattle from sunlight compared to no shade, and that the effectiveness of tree shade for sunlight protection is at an intermediate level.
Asunto(s)
Antioxidantes/efectos de la radiación , Bovinos/fisiología , Estrés Oxidativo , Luz Solar , Árboles , Bienestar del Animal , Animales , Animales Domésticos , Antioxidantes/metabolismo , Regulación de la Temperatura Corporal/efectos de la radiación , Trastornos de Estrés por Calor/etiología , Trastornos de Estrés por Calor/prevención & control , Trastornos de Estrés por Calor/veterinaria , Linfocitos/metabolismo , Linfocitos/efectos de la radiación , Neutrófilos/metabolismo , Neutrófilos/efectos de la radiación , Sudoración/efectos de la radiación , TailandiaRESUMEN
This study computationally assessed the temperature elevations due to electromagnetic wave energy deposition during magnetic resonance imaging in non-pregnant and pregnant woman models. We used a thermal model with thermoregulatory response of the human body for our calculations. We also considered the effect of blood temperature variation on body core temperature. In a thermal equilibrium state, the temperature elevations in the intrinsic tissues of the woman and fetal tissues were 0.85 and 0.61 degrees C, respectively, at a whole-body averaged specific absorption rate of 2.0 W kg(-1), which is the restriction value of the International Electrotechnical Commission for the normal operating mode. As predicted, these values are below the temperature elevation of 1.5 degrees C that is expected to be teratogenic. However, these values exceeded the recommended temperature elevation limit of 0.5 degrees C by the International Commission on Non-Ionizing Radiation Protection. We also assessed the irradiation time required for a temperature elevation of 0.5 degrees C at the aforementioned specific absorption rate. As a result, the calculated irradiation time was 40 min.
Asunto(s)
Campos Electromagnéticos/efectos adversos , Exposición a Riesgos Ambientales/efectos adversos , Feto/efectos de la radiación , Imagen por Resonancia Magnética/efectos adversos , Temperatura , Temperatura Corporal/efectos de la radiación , Regulación de la Temperatura Corporal/efectos de la radiación , Femenino , Feto/fisiología , Humanos , Modelos Anatómicos , Modelos Biológicos , Embarazo , Ondas de Radio/efectos adversos , Sudoración/efectos de la radiaciónRESUMEN
Bright light (BL) exposure at night leads to suppressed secretion of melatonin and an attenuated fall in internal temperature at rest from the night to the early morning. However, it is unknown at the present whether typical diurnal variations in reflex responses to thermal challenges are similarly affected by BL exposure at night. We investigated the control of cutaneous vasodilator and sweating responses to hyperthermia in the early morning after artificial BL exposure at night, compare with dim light (DL) exposure. Six subjects stayed awake in a semi-supine position under DL (120 lx) or BL (2800 lx) conditions between 21.00 and 04.30 h. Urine samples were collected at 04.30 h. Beginning at 05.30 h, the lower legs were immersed for 50 min in 42 degrees C water. The subjects remained awake for 21 h until the end of hot water immersion. Urinary 6-sulphatoxymelatonin levels following BL were significantly lower than after DL. Oesophageal temperature (T es) before heating was significantly higher following BL [36.41+/-0.10 (DL) vs. 36.55+/-0.09 (BL) degrees C]. The T es thresholds for the onset of cutaneous vasodilation and sweating were significantly higher with BL than with DL conditions (approximately 0.15 degrees C, respectively). We found that the internal temperature threshold for thermoregulatory control of cutaneous vasodilation and sweating responses to passive heating in the early morning can be modified by the level of light exposure the prior night. Thus both basal internal temperature and the regulation of internal temperature are modified by BL exposure at night.
Asunto(s)
Regulación de la Temperatura Corporal/fisiología , Luz , Estimulación Luminosa/métodos , Piel/irrigación sanguínea , Sudoración/fisiología , Vasodilatación/fisiología , Adulto , Regulación de la Temperatura Corporal/efectos de la radiación , Oscuridad , Humanos , Masculino , Piel/efectos de la radiación , Sudoración/efectos de la radiación , Vasodilatación/efectos de la radiaciónRESUMEN
Since 1994, our research has demonstrated how thermophysiological responses are mobilized in human volunteers exposed to three radio frequencies, 100, 450, and 2450 MHz. A significant gap in this frequency range is now filled by the present study, conducted at 220 MHz. Thermoregulatory responses of heat loss and heat production were measured in six adult volunteers (five males, one female, aged 24-63 years) during 45 min whole body dorsal exposures to 220 MHz radio frequency (RF) energy. Three power densities (PD = 9, 12, and 15 mW/cm(2) [1 mW/cm(2) = 10 W/m(2)], whole body average normalized specific absorption rate [SAR] = 0.045 [W/kg]/[mW/cm(2)] = 0.0045 [W/kg]/[W/m(2)]) were tested at each of three ambient temperatures (T(a) = 24, 28, and 31 degrees C) plus T(a) controls (no RF). Measured responses included esophageal (T(esoph)) and seven skin temperatures (T(sk)), metabolic rate (M), local sweat rate, and local skin blood flow (SkBF). Derived measures included heart rate (HR), respiration rate, and total evaporative water loss (EWL). Finite difference-time domain (FDTD) modeling of a seated 70 kg human exposed to 220 MHz predicted six localized "hot spots" at which local temperatures were also measured. No changes in M occurred under any test condition, while T(esoph) showed small changes (< or =0.35 degrees C) but never exceeded 37.3 degrees C. As with similar exposures at 100 MHz, local T(sk) changed little and modest increases in SkBF were recorded. At 220 MHz, vigorous sweating occurred at PD = 12 and 15 mW/cm(2), with sweating levels higher than those observed for equivalent PD at 100 MHz. Predicted "hot spots" were confirmed by local temperature measurements. The FDTD model showed the local SAR in deep neural tissues that harbor temperature-sensitive neurons (e.g., brainstem, spinal cord) to be greater at 220 than at 100 MHz. Human exposure at both 220 and 100 MHz results in far less skin heating than occurs during exposure at 450 MHz. However, the exposed subjects thermoregulate efficiently because of increased heat loss responses, particularly sweating. It is clear that these responses are controlled by neural signals from thermosensors deep in the brainstem and spinal cord, rather than those in the skin.
Asunto(s)
Regulación de la Temperatura Corporal/efectos de la radiación , Campos Electromagnéticos , Irradiación Corporal Total , Adulto , Temperatura Corporal/efectos de la radiación , Tronco Encefálico/efectos de la radiación , Metabolismo Energético/efectos de la radiación , Esófago/efectos de la radiación , Femenino , Frecuencia Cardíaca/efectos de la radiación , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Neuronas/efectos de la radiación , Dosis de Radiación , Flujo Sanguíneo Regional/efectos de la radiación , Respiración/efectos de la radiación , Piel/irrigación sanguínea , Piel/efectos de la radiación , Temperatura Cutánea/efectos de la radiación , Médula Espinal/efectos de la radiación , Sudoración/efectos de la radiación , Pérdida Insensible de Agua/efectos de la radiaciónRESUMEN
The effects of acupuncture stimulation at 5 Hz and 100 Hz on mental stress-induced sweating were analyzed, and the mechanisms involved were examined using the rate of sweat expulsion as an estimate of central sudomotor outflow. Mental arithmetic was imposed on 25 young healthy volunteers for 2 min before, during and after the stimulation. Acupuncture stimulation was delivered to either the Zusanli (leg) or Hegu (hand) acupoint, and the sweat rate was measured quantitatively during mental arithmetic on the palm or the sole, respectively. When stimulation at 5 Hz was applied to the Zusanli acupoint, the palmar sweat rate (paSR), rate of sweat expulsion (Fsw) and paSR/Fsw were reduced during the stimulation, whereas when it was applied to the Hegu acupoint, plantar SR (plSR) and Fsw were reduced, but plSR/Fsw was not altered. When stimulation at 100 Hz was applied to Zusanli, paSR and paSR/Fsw were reduced, but Fsw was unchanged whereas when it was applied to Hegu, neither plSR, Fsw nor plSR/Fsw was altered. The results suggest that acupuncture stimulation at 5 Hz affects both the supraspinal rhythm-generating mechanism and the mechanisms situated below (probably the spinal cord), whereas stimulation at 100 Hz only affects the mechanisms below the rhythm-generating mechanism. Thus, acupuncture stimulation at 5 Hz and at 100 Hz may reduce mental stress-induced sweating through different mechanisms.
Asunto(s)
Acupuntura/métodos , Inhibición Psicológica , Estrés Psicológico/fisiopatología , Estrés Psicológico/terapia , Sudoración/efectos de la radiación , Puntos de Acupuntura , Adulto , Análisis de Varianza , Relación Dosis-Respuesta en la Radiación , Femenino , Lateralidad Funcional , Humanos , Masculino , Modelos Biológicos , Sudoración/fisiología , Factores de TiempoRESUMEN
Both thin afferent (nociceptors) and efferent (sympathetic sudomotor) nerve fibers can be activated electrically and chemically, resulting in neurogenic erythema and sweating. These reactions have been used before to assess the impairment of sympathetic and nociceptor fibers in humans. In this study, electrically induced sweating and erythema were assessed simultaneously in the foot dorsum and thigh, and were compared to chemically induced activation. Reproducible intensity-response relations (stimulation intensities 0-30 mA, 1 Hz) were obtained from 32 subjects. The steepest increase of the sweat response was induced at lower intensities as compared to that of the erythema (18.3 mA vs. 25.7 mA, p<0.01) and reached a plateau for intensities above 25 mA, suggesting lower electrical thresholds for sudomotor fibers. Maximum flare areas induced electrically with 30 mA were smaller than those evoked chemically (flare size: 4.5 cm2 vs. 10.6 cm2). In contrast, the electrically evoked sweating rate was higher than that evoked chemically (acetylcholine, or ACh; sweating rate 0.31 vs. 0.21 microl/cm2/min, p<0.01), which might be attributed to an increased effectiveness of synchronized discharge in sympathetic fibers upon electrical stimulation.
Asunto(s)
Estimulación Eléctrica , Eritema/etiología , Piel , Estimulación Química , Sudoración/efectos de los fármacos , Sudoración/efectos de la radiación , Acetilcolina/farmacología , Adulto , Factores de Edad , Anciano , Análisis de Varianza , Relación Dosis-Respuesta en la Radiación , Femenino , Pie/fisiología , Lateralidad Funcional , Humanos , Flujometría por Láser-Doppler , Masculino , Persona de Mediana Edad , Reflejo/efectos de los fármacos , Reproducibilidad de los Resultados , Factores Sexuales , Piel/efectos de los fármacos , Piel/efectos de la radiación , Muslo/fisiologíaRESUMEN
BACKGROUND: This study examines the use of a simple thermoregulatory model for the human body exposed to extended (45 minute) exposures to radiofrequency/microwave (RF/MW) energy at different frequencies (100, 450, 2450 MHz) and under different environmental conditions. The exposure levels were comparable to or above present limits for human exposure to RF energy. METHODS: We adapted a compartmental model for the human thermoregulatory system developed by Hardy and Stolwijk, adding power to the torso skin, fat, and muscle compartments to simulate exposure to RF energy. The model uses values for parameters for "standard man" that were originally determined by Hardy and Stolwijk, with no additional adjustment. The model predicts changes in core and skin temperatures, sweat rate, and changes in skin blood flow as a result of RF energy exposure. RESULTS: The model yielded remarkably good quantitative agreement between predicted and measured changes in skin and core temperatures, and qualitative agreement between predicted and measured changes in skin blood flow. The model considerably underpredicted the measured sweat rates. CONCLUSIONS: The model, with previously determined parameter values, was successful in predicting major aspects of human thermoregulatory response to RF energy exposure over a wide frequency range, and at different environmental temperatures. The model was most successful in predicting changes in skin temperature, and it provides insights into the mechanisms by which the heat added to body by RF energy is dissipated to the environment. Several factors are discussed that may have contributed to the failure to account properly for sweat rate. Some features of the data, in particular heating of the legs and ankles during exposure at 100 MHz, would require a more complex model than that considered here.
Asunto(s)
Regulación de la Temperatura Corporal/efectos de la radiación , Modelos Biológicos , Ondas de Radio , Adulto , Anciano , Femenino , Calor , Humanos , Masculino , Concentración Máxima Admisible , Microondas , Persona de Mediana Edad , Flujo Sanguíneo Regional/efectos de la radiación , Piel/irrigación sanguínea , Temperatura Cutánea/efectos de la radiación , Sudoración/efectos de la radiación , Factores de TiempoRESUMEN
PURPOSE: The morphological effect of radiation on the skin has been adequately analyzed, but the functional effect has received little attention. The purpose of this study was to examine the long-term effects of radiation on the skin from the viewpoint of function. MATERIALS AND METHODS: Physiological changes in the irradiated skin of patients who had undergone breast-conserving therapy for the treatment of breast cancer were examined throughout the follow-up period. Thermal stimulation was applied to both breasts, and changes in skin temperature and sweating reactivity of irradiated and non-irradiated skin were measured. RESULTS: From three weeks to the end of radiotherapy, the resting skin temperature of the irradiated region was significantly elevated, while the rate of sweating was lower. More than two years after radiotherapy, the elevated resting skin temperature of the irradiated region had returned to within the range observed for non-irradiated skin, although an abnormally high increase in skin temperature after thermal stimulation continued to be observed for more than two years after radiotherapy. At the same time, sweating after thermal stimulation continued to be suppressed. CONCLUSION: Present observations suggest that functional effects, such as the skin temperature and sweating ability of irradiated skin, persist longer than readily visible morphological changes.
Asunto(s)
Temperatura Cutánea/efectos de la radiación , Piel/efectos de la radiación , Adulto , Anciano , Regulación de la Temperatura Corporal/efectos de la radiación , Mama/efectos de la radiación , Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Femenino , Estudios de Seguimiento , Calor , Humanos , Estudios Longitudinales , Mastectomía Segmentaria , Persona de Mediana Edad , Radioterapia Adyuvante , Sudoración/efectos de la radiación , Termografía , Factores de TiempoRESUMEN
Thermophysiological responses of heat production and heat loss were measured in seven adult volunteers (six males and one female, aged 31-74 years) during 45 min dorsal exposures of the whole body to 100 MHz continuous wave (CW) radio frequency (RF) energy. Three power densities (PD) (average PD = 4, 6, and 8 mW/cm(2); whole body specific absorption rate [SAR] = 0.068 [W/kg]/[mW/cm(2)]) were tested in each of three ambient temperatures (T(a) = 24, 28, and 31 degrees C), as well as in T(a) controls (no RF). A standardized protocol (30 min baseline, 45 min RF or sham exposure, 10 min baseline) was used. Measured responses included esophageal and seven skin temperatures, metabolic heat production, local sweat rate, and local skin blood flow. No changes in metabolic heat production occurred under any test condition. Unlike published results of similar exposures at 450 and 2450 MHz, local skin temperatures, even those on the back that were irradiated directly, changed little or not at all during 100 MHz exposures. The sole exception was the temperature of the ankle skin, which increased by 3-4 degrees C in some subjects at PD = 8 mW/cm(2). During the 45 min RF exposure, esophageal temperature showed modest changes (range = -0.15 to 0.13 degrees C) and never exceeded 37.2 degrees C. Thermoregulation was principally controlled by appropriate increases in evaporative heat loss (sweating) and, to a lesser extent, by changes in skin blood flow. Because of the deep penetration of RF energy at this frequency, effectively bypassing the skin, these changes must have been stimulated by thermal receptors deep in the body rather than those located in the skin.