Drop In Skin Temperature Research Articles

Bioinspired Hierarchical Multi-Protective Membrane for Extreme Environments via Co-Electrospinning-Electrospray Strategy.

Extreme environments can cause severe harm to human health, and even threaten life safety. Lightweight, breathable clothing with multi-protective functions would be of great application value. However, integrating multi-protective functions into nanofibers in a facile way remains a great challenge. Here, a one-step co-electrospinning-electrospray strategy is developed to fabricate a superhydrophobic multi-protective membrane (S-MPM). The water contact angle of S-MPM can reach up to 164.3°. More importantly, S-MPM can resist the skin temperature drop (11.2 °C) or increase (17.2 °C) caused by 0 °C cold or 70 °C hot compared with pure electrospun membrane. In the cold climate (-5 °C), the anti-icing time of the S-MPM is extended by 2.52 times, while the deicing time is only 1.45 s due to the great photothermal effect. In a fire disaster situation, the total heat release and peak heat release rate values of flame retarded S-MPM drop sharply by 24.2% and 69.3%, respectively. The S-MPM will serve as the last line of defense for the human body and has the potential to trigger a revolution in the practical application of next-generation functional clothing.

Angiotensinergic neurotransmission in the bed nucleus of the stria terminalis is involved in cardiovascular responses to acute restraint stress in rats.

The brain angiotensin II acting via AT1 receptors is a prominent mechanism involved in physiological and behavioral responses during aversive situations. The AT2 receptor has also been implicated in stress responses, but its role was less explored. Despite these pieces of evidence, the brain sites related to control of the changes during aversive threats by the brain renin-angiotensin system (RAS) are poorly understood. The bed nucleus of the stria terminalis (BNST) is a limbic structure related to the cardiovascular responses by stress, and components of the RAS system were identified in this forebrain region. Therefore, we investigated the role of angiotensinergic neurotransmission present within the BNST acting via local AT1 and AT2 receptors in cardiovascular responses evoked by an acute session of restraint stress in rats. For this, rats were subjected to bilateral microinjection of either the angiotensin-converting enzyme inhibitor captopril, the selective AT1 receptor antagonist losartan, or the selective AT2 receptor antagonist PD123319 before they underwent the restraint stress session. We observed that BNST treatment with captopril reduced the decrease in tail skin temperature evoked by restraint stress, without affecting the pressor and tachycardic responses. Local AT2 receptor antagonism within the BNST reduced both the tachycardia and the drop in tail skin temperature during restraint. Bilateral microinjection of losartan into the BNST did not affect the restraint-evoked cardiovascular changes. Taken together, these data indicate an involvement of BNST angiotensinergic neurotransmission acting via local AT2 receptors in cardiovascular responses during stressful situations.

Sex differences during a cold-stress test in normobaric and hypobaric hypoxia: A randomized controlled crossover study.

Cold and hypoxia are two stressors that are frequently combined and investigated in the scientific literature. Despite the growing literature regarding normobaric hypoxia (NH) and hypobaric hypoxia (HH), responses between females and males are less often evaluated. Therefore, this study aims to investigate the physiological sex differences following a cold-stress test under normoxia, normobaric- and hypobaric hypoxia. A total of n = 10 females (24.8 ± 5.1 years) and n = 10 males (30.3 ± 6.3 years) from a university population volunteered for this study. The cold-stress test (CST) of the right hand (15°C for 2 min) was performed using a randomised crossover design in normobaric normoxia, NH and HH. The change (∆) from baseline to post-CST up to 15 min was analysed for cutaneous vascular conductance (CVC) and the hands’ skin temperature, whilst the mean values across time (post-CST up to 15 min) were assessed for peripheral oxygen saturation (SpO2), thermal sensation- and comfort. Pressure pain threshold (PPT) was assessed after the post-CST 15 min period. The hands’ skin temperature drop was higher (p = 0.01) in the female group (∆3.3 ± 1.5°C) compared to the male group (∆1.9 ± 0.9°C) only in NH. Females (−0.9 ± 0.5) rated this temperature drop in NH to feel significantly colder (p = 0.02) compared to the males (−0.2 ± 0.7). No differences were observed between sexes in NN, NH, and HH for ∆CVC, SpO2, thermal comfort and PPT. In conclusion, females and males show similar reactions after a CST under normoxia and hypoxia. Sex differences were observed in the local skin temperature response and thermal sensation only in NH.

Skin Temperature: The Impact of Perfusion, Epidermis Thickness, and Skin Wetness

This work aimed to elucidate the primary factors which affect skin temperature. A simple thermophysical model of the skin, which accounts for radiative, convective, and evaporative heat losses, has been developed to address it. The model is based on the skin’s morphology and consists of passive (nonviable tissue) and active (viable tissue) layers. The bioheat equation was solved for these layers using realistic assumptions. It was found that other than the ambient temperature, blood perfusion and epidermis thickness are the primary factors responsible for the skin temperature variations. The main temperature drop in the skin is attributed to the cooling of the blood in the venous plexus. The temperature drop in the epidermis is on the scale of 0.1 °C for the normal epidermis but can be 1.5–2 °C or higher in calluses. Thus, local skin temperature variations can indicate the epidermis thickness variations, particularly in callus-prone areas. The effects of relative air humidity and skin wetness on skin temperature were also quantified. The presence of free moisture on the skin (e.g., wet wound) significantly increases the heat transfer, resulting in a skin temperature drop, which can be on the scale of several degrees Celsius. The relative air humidity significantly contributes (by slowing heat dissipation) only in the case of evaporative heat loss from wet skin. Therefore, wet skin is undesirable and should be avoided during a thermographic assessment.

Reading Your Emotions in My Physiology? Reliable Emotion Interpretations in Absence of a Robust Physiological Resonance.

Affective states are expressed in an individual’s physical appearance, ranging from facial expressions and body postures, to indicators of physiological arousal (e.g., a blush). Confirming the claimed communicative function of these markers, humans are capable of distinguishing between a variety of discrete emotion displays. In an attempt to explain the underlying mechanism, characteristic bodily changes within the observer, including physiological arousal and mimicry, have been suggested to facilitate the interpretation of an expression. The current study aims to create a holistic picture of emotion perception by (1) using three different sources of emotional information (prototypical facial expressions, bodily expressions, and subtle facial cues) and (2) measuring changes in multiple physiological signals (facial electromyography, skin conductance level, skin temperature, and pupil size). While participants clearly discriminated between perceived emotional expressions, there was no overall 1–1 correspondence with their physiological responses. Some specific but robust effects were observed. Angry facial expressions were consistently responded to with a peak in skin conductance level. Furthermore, sad body expressions were associated with a drop in skin temperature. In addition to being the best recognized expression, viewing happy faces elicited congruent facial muscle responses, which supports the potential role of embodied simulation in emotion recognition. Lastly, tears were not only rated as highly emotional intense but also evoked a peak in skin conductance level in the observer. The absence of distinct physiological responses to other expressions could be explained by the lacking functionality of affect sharing in a non-interactive experimental context. Consequentially, emotional alignment in body and mind might especially take place in real social situations, which should be considered in future research.Supplementary InformationThe online version contains supplementary material available at 10.1007/s42761-021-00083-5.

Cardiovascular Reactivity to a Novel Stressor: Differences on Susceptible and Resilient Rats to Social Defeat Stress.

Prolonged and heightened responses to stress are known factors that influence the development of mood disorders and cardiovascular diseases. Moreover, the coping strategies related to the experience of adverse events, i.e., resilience or the susceptibility to stress, are determinants for the individual risk of developing such diseases. Susceptible rats to the social defeat stress (SDS), identified by the social interaction test (SIT), show behavioral and cardiovascular alterations after SDS exposure that are not found in resilient rats. However, it is not elucidated yet how the cardiovascular system of susceptible and resilient phenotypes responds to a new stressor after SDS exposure. Thus, using the SDS exposure followed by the SIT, we evaluated heart rate, blood pressure (BP), tail skin temperature, and circulating corticosterone responses to an acute session of restraint stress in susceptible and resilient rats to SDS. Susceptible rats showed resting tachycardia and exaggerated BP response to restraint stress, while resilient rats did not present such alterations. In contrast, both phenotypes showed increased plasma corticosterone and a drop in tail skin temperature to restraint stress, which was similar to that observed in control animals. Our results revealed an increased cardiovascular reactivity in response to a new stressful stimulus in susceptible rats, which might be related to a greater risk for the development of cardiovascular diseases.

Differential roles of prelimbic and infralimbic cholinergic neurotransmissions in control of cardiovascular responses to restraint stress in rats

Previous studies showed a prominent role of the medial prefrontal cortex (mPFC), especially the prelimbic (PL) and infralimbic (IL) subregions, in behavioral and physiological responses to stressful stimuli. Nevertheless, the local neurochemical mechanisms involved are not completely understood. In this sense, previous studies identified cholinergic terminals within the mPFC, and stressful stimuli increased local acetylcholine release. Despite these pieces of evidence, the specific role of cholinergic neurotransmission in different subregions of the mPFC controlling the cardiovascular responses to stress has never been systematically evaluated. Therefore, the purpose of this study was to investigate the involvement of cholinergic neurotransmission present within PL and IL in cardiovascular responses to an acute session of restraint stress in rats. For this, rats received bilateral microinjection of the choline uptake inhibitor hemicholinium-3 before exposure to restraint stress. The arterial pressure and heart rate (HR) increases and the decrease in tail skin temperature as an indirect measurement of sympathetically-mediated cutaneous vasoconstriction were recorded throughout the restraint stress session. The results showed that the depletion of acetylcholine within the PL caused by local microinjection of hemicholinium-3 decreased the tachycardia to restraint stress, but without affecting the pressor response and the drop in tail skin temperature. Conversely, IL treatment with hemicholinium-3 decreased the restraint-evoked pressor response and the sympathetically-mediated cutaneous vasoconstriction without interfering with the HR response. Taken together, these results indicate functional differences of cholinergic neurotransmission within the PL and IL in control of cardiovascular and autonomic responses to stressful stimuli.

Exoskeletons and Exosuits Could Benefit from Mode-Switching Body Interfaces That Loosen/Tighten to Improve Thermal Comfort.

Exoskeletons and exosuits (exos) are wearable devices that physically assist movement. User comfort is critically important for societal adoption of exos. Thermal comfort (a person’s satisfaction with their thermal environment) represents a key design challenge. Exos must physically attach/interface to the body to apply forces, and these interfaces inevitably trap some heat. It is envisioned that thermal comfort could be improved by designing mode-switching exo interfaces that temporarily loosen around a body segment when assistive forces are not being applied. To inform exo design, a case series study (N = 4) based on single-subject design principles was performed. Our objective was to assess individual responses to skin temperature and thermal comfort during physical activity with a Loose leg-sleeve interface compared with a Form-Fitting one, and immediately after a Form-Fitting sleeve switched to Loose. Skin under the Loose sleeve was 2–3 °C (4–6 °F) cooler after 25 min of physical activity, and two of four participants reported the Loose sleeve improved their thermal comfort. After completion of the physical activity, the Form-Fitting sleeve was loosened, causing a 2–4 °C (3–8 °F) drop in skin temperature underneath for all participants, and two participants to report slightly improved thermal comfort. These findings confirmed that an exo that can quickly loosen its interface when assistance is not required—and re-tighten when it is— has the potential to enhance thermal comfort for some individuals and environments. More broadly, this study demonstrates that mode-switching mechanisms in exos can do more than adjust physical assistance: they can also exploit thermodynamics and facilitate thermoregulation in a way that enhances comfort for exo users.

Thermodynamic Correlation between Actual Temperature and Cryogenic Flow Rate in an Empty Cryosauna

The objective of this study was to monitor the actual temperature in an empty partial body cryotherapy cabin throughout the cooling phase that precedes the cryotherapy session. It was shown that after 9 minutes of cooling, the minimum temperature recorded inside the empty cryosauna was −66 °C while the temperature was set to −140 °C. To further investigate the relationship between the use of nitrogen as a cryogenic fluid and the actual temperature inside the cabin, we used a numerical method and modeled the convective heat transfer for 3 different flow rates (0.01, 0.03 and 0.05 kg/s). According to the simulations, a temperature of about −100 °C may be reached after 3 minutes with a flow rate of 0.05 kg/s against 5 minutes with a flow rate of 0.03 kg/s. With the lowest flow rate, it would be possible to reach −60 °C after 10 minutes. A key assumption is that a too low nitrogen flow does not provide a thermal gradient able to induce the drop in skin temperature required to achieve therapeutic effectiveness.

Bilateral skin temperature drop and warm sensibility decrease following modulation of body part ownership through mirror-box illusion

The implicit and explicit awareness of owning a body and its parts is a constant accompaniment in our everyday life and our interaction with the outside world. The way in which we build and maintain a coherent sense of body ownership is not fully understood. It has been postulated that the integration between exteroceptive, interoceptive, and proprioceptive signals may play a fundamental role in the sense of body ownership. For instance, studies on healthy subjects and brain-damaged patients have suggested that alterations in the sense of body ownership are coupled with autonomic signal changes, such as thermoregulatory reactions. However, the available evidence is conflicting, possibly due to shortcomings in the experimental paradigm that previous studies have adopted. In this study, we explore the relationship between body ownership, thermoregulation, and thermal sensitivity through a novel application of the mirror-box illusion paradigm, overcoming some of the limitations of previous studies. We find a bilateral decrease in hand skin temperature, together with reduced thermal sensitivity for warm thermal stimuli following the induction of the illusion of ownership towards the participant's reflected hand. These findings demonstrate the importance of the orchestration of exteroceptive (e.g., visual), autonomic (e.g., body temperature) and proprioceptive (e.g., position and movement of the body) signals in maintaining a coherent sense of body ownership.

Habituation of the cardiovascular response to restraint stress is inhibited by exposure to other stressor stimuli and exercise training.

This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as treadmill exercise training, in the habituation of the cardiovascular response upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted for 10 consecutive days, whereas treadmill training was performed for 1 h per day, 5 days per week for 8 weeks. We observed that the increase in serum corticosterone was reduced during both the stress and the recovery period of the 10th session of restraint. Habituation of the cardiovascular response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation or treadmill exercise training inhibited the habituation of the restraint-evoked tachycardia. Additionally, CVS increased the blood pressure response at the 10th session of restraint, whereas social isolation enhanced both the tachycardia during the first session and the drop in skin temperature at the 10th session of restraint. Taken together, these findings provide new evidence that pathologies evoked by stress might be related to impairment in the habituation process to homotypic stressors.

Human wetness perception of fabrics under dynamic skin contact

This experiment studied textile (surface texture, thickness) and non-textile (local skin temperature changes, stickiness sensation and fabric-to-skin pressure) parameters affecting skin wetness perception under dynamic interactions. Changes in fabric texture sensation between WET and DRY states and their effect on pleasantness were also studied. The surface texture of eight fabric samples, selected for their different structures, was determined from surface roughness measurements using the Kawabata Evaluation System. Sixteen participants assessed fabric wetness perception, at high pressure and low pressure conditions, stickiness, texture and pleasantness sensation on the ventral forearm. Differences in wetness perception (p < 0.05) were not determined by texture properties and/or texture sensation. Stickiness sensation and local skin temperature drop were determined as predictors of wetness perception (r2 = 0.89), and although thickness did not correlate with wetness perception directly, when combined with stickiness sensation it provided a similar predictive power (r2 = 0.86). Greater (p < 0.05) wetness perception responses at high pressure were observed compared with low pressure. Texture sensation affected pleasantness in DRY (r2 = 0.89) and WET (r2 = 0.93). In WET, pleasantness was significantly reduced (p < 0.05) compared to DRY, likely due to the concomitant increase in texture sensation (p < 0.05). In summary, under dynamic conditions, changes in stickiness sensation and wetness perception could not be attributed to fabric texture properties (i.e. surface roughness) measured by the Kawabata Evaluation System. In dynamic conditions thickness or skin temperature drop can predict fabric wetness perception only when including stickiness sensation data.

Both N-methyl-D-aspartate and non-N-methyl-D-aspartate glutamate receptors in the bed nucleus of the stria terminalis modulate the cardiovascular responses to acute restraint stress in rats.

The bed nucleus of the stria terminalis (BNST) is a forebrain structure that has been implicated on cardiovascular responses evoked by emotional stress. However, the local neurochemical mechanisms mediating the BNST control of stress responses are not fully described. In our study we investigated the involvement of glutamatergic neurotransmission within the BNST in cardiovascular changes evoked by acute restraint stress in rats. For this study, we investigated the effects of bilateral microinjections of selective antagonists of either N-methyl-D-aspartate (NMDA) or non-NMDA glutamate receptors into the BNST on the arterial pressure and heart rate increase and the decrease in tail skin temperature induced by acute restraint stress. Microinjection of the selective NMDA glutamate receptor antagonist LY235959 (1 nmol/100 nL) into the BNST decreased the tachycardiac response to restraint stress, without affecting the arterial pressure increase and the drop in skin temperature. Bilateral BNST treatment with the selective non-NMDA glutamate receptor NBQX (1 nmol/100 nL) decreased the heart rate increase and the fall in tail skin temperature, without affecting the blood pressure increase. These findings indicate a facilitatory influence of BNST glutamatergic neurotransmission via coactivation of local NMDA and non-NMDA receptors on the tachycardiac response to stress, whereas control of sympathetic-mediated cutaneous vasoconstriction is selectively mediated by local non-NMDA glutamate receptors.

Human wetness perception in relation to textile water absorption parameters under static skin contact

Skin wetness perception (WP) greatly affects thermal and sensorial discomfort in clothing and as such is of great interest to the clothing industry. Following neurophysiological studies of WP, this study looks at textile parameters affecting WP. Twenty-four fabrics varying in thickness, fiber type and absorption capacity were studied. Using 12 participants (males/females), the WP induced was studied in four wetness states: 1. Dry; 2. absolute (ABS), all having the same absolute water content of 2400 µL per sample (=0.24 µL mm−2); 3. 100REL, saturated with water to their individual absorption capacity; 4. 50REL, to 50% of the value in 3. As total absorption capacity was highly correlated ( r = 0.99) to fabric thickness, conditions 3 and 4 were equivalent to having the same water content per volume of textile, i.e. 0.8 and 0.4 µL mm−3, respectively. Samples were applied to the upper back statically to minimize the contribution of surface roughness/friction. WP was highly correlated to drop in skin temperature induced by the wet fabric, and increased with application pressure of the fabric. No effect of fiber type was observed. In REL, with equal µL mm−3, WP showed a positive correlation to total fabric water-content-per-area (µL mm−2), and thus also to thickness, given the correlation between the latter two, with saturation above 1.5 µL mm−2. In ABS, on the other hand, with equal µL mm−2, and thus with relative water content (µL mm µL mm−3) inversely proportional to thickness, WP was also inversely proportional to thickness. Thus WP showed opposing responses depending on the wetting type, indicating that the methodology of manipulating water content should be selected in relation to the product end-use.

Does local cryotherapy improve thermal diagnosis similar to whole-body cryotherapy in spinal diseases?

Thermal imaging has been used for patients with spinal diseases who were qualified by their physicians for whole-body treatment or local cryotherapy. The experimental groups of patients consisted of 20 males aged 51.6 ± 9.0 (12 treated by whole-body cryotherapy and 8 by local cryotherapy). The distribution of the skin surface temperature was monitored by using a Thermovision Camera E60 before and immediately after body cooling. The chosen spinal region (Th5/Th6–L5/S1) was taken into consideration for all of the research groups. An essential drop in skin temperature and a better differentiation of the body surface temperatures (leading to an increase in the diagnostic value of thermography) was observed after both methods of cold impact. In order to estimate the usefulness of thermovision used after body cooling, the quantitative parameters including temperature contrast—the difference between the maximum and minimum temperatures before and after cold impact and relative contrast ratio (related to the average temperature of the selected area of interest, before and after cooling, respectively)—were compared for both kinds of medical treatment. The statistical analysis proved that significant differences between the parameters obtained before and after body cooling in the case that patients treated by local and whole-body cryotherapy are similar. However, local therapy is cheaper and easy for application while whole-body therapy can give more information about the state of soft tissues for the whole back.

Skin temperature reveals the intensity of acute stress

Acute stress triggers peripheral vasoconstriction, causing a rapid, short-term drop in skin temperature in homeotherms. We tested, for the first time, whether this response has the potential to quantify stress, by exhibiting proportionality with stressor intensity. We used established behavioural and hormonal markers: activity level and corticosterone level, to validate a mild and more severe form of an acute restraint stressor in hens (Gallus gallus domesticus). We then used infrared thermography (IRT) to non-invasively collect continuous temperature measurements following exposure to these two intensities of acute handling stress. In the comb and wattle, two skin regions with a known thermoregulatory role, stressor intensity predicted the extent of initial skin cooling, and also the occurrence of a more delayed skin warming, providing two opportunities to quantify stress. With the present, cost-effective availability of IRT technology, this non-invasive and continuous method of stress assessment in unrestrained animals has the potential to become common practice in pure and applied research.

Remote Limb Ischemic Preconditioning: A Neuroprotective Technique in Rodents.

Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. Sublethal ischemia has also been shown to upregulate protective mechanisms in remote tissues. A brief period of ischemia (5-10 min) in the hind limb of mammals induces self-protective responses in the brain, lung, heart and retina. The effect is known as remote ischemic preconditioning (RIP). It is a therapeutically promising way of protecting vital organs, and is already under clinical trials for heart and brain injuries. This publication demonstrates a controlled, minimally invasive method of making a limb - specifically the hind limb of a rat - ischemic. A blood pressure cuff developed for use in human neonates is connected to a manual sphygmomanometer and used to apply 160 mmHg pressure around the upper part of the hind limb. A probe designed to detect skin temperature is used to verify the ischemia, by recording the drop in skin temperature caused by pressure-induced occlusion of the leg arteries, and the rise in temperature which follows release of the cuff. This method of RIP affords protection to the rat retina against bright light-induced damage and degeneration.

Effects of two different battings (sheep wool versus polyester microfiber) in an outdoor jacket on the heat and moisture management and comfort sensation in the cold

Wool in outdoor clothing systems is stated to be a good temperature and humidity regulator giving the wearer a warm and dry feeling during physical activities in the cold. The objective was to compare two different battings (sheep wool “tirolwool” (TW) versus polyester microfiber (PMF)) in an outdoor jacket of a two-layer outdoor clothing system consisting of a shirt and jacket on the heat and moisture management and comfort sensation during a moderate mountain walking protocol which was followed by a cool-down phase in the cold (−5℃, 43% relative humidity). Due to its beneficial moisture management properties it was hypothesized that TW in the outermost layer would cause a higher skin and core temperature, reduce the after chill effect, increase moisture transfer, decrease moisture accumulation within the clothing system, and lead to more pleasant comfort sensations. Twelve sport students performed the simulated walking protocol (60 min, 7.7% inclination, 5 km/h) and cool-down phase (20 min) with TW and PMF in a climatic chamber. The use of TW compared to PMF was stronger moisture absorbent led to a dryer shirt ( p = 0.043) and lower humidity underneath the shirt and jacket (chest: p ≤ 0.05). Core temperature ( p = 0.017) and skin temperature drop (chest: p = 0.003) were attenuated with TW after the physical activity. Therefore, the after chill effect was reduced with TW but moisture accumulated to a higher extent in the jacket ( p = 0.001), which might lead to a longer drying rate. Correlation analysis revealed that tested underwear blended with merino wool, elastane, and polyamide might feel less scratchy in the slightly damp state than in the dry state.

Transient flow response after femoral artery catheterization for diagnostic neuroangiography in infants and children: Doppler US assessment of the ipsilateral femoral artery.

Hemodynamic changes in the distal arteries during transfemoral catheterization in children have not been documented. To evaluate arterial flow changes of the lower extremities ipsilateral to the puncture site using Doppler US during transfemoral cerebral angiography in children. Twenty-seven children who underwent transfemoral cerebral angiography at our institution between April 2013 and August 2013 compose our study population. Doppler US was performed to evaluate diameters and peak systolic velocities of the common femoral artery and superficial femoral artery before and after femoral sheath insertion. Children were classified into three groups based on the spectral waveform changes of the superficial femoral artery after femoral sheath insertion. Thereafter, one-way ANOVA followed by the Bonferroni post-hoc comparisons test were performed to compare values among the groups. Mean common femoral artery and superficial femoral artery baseline diameters were 4.10 mm and 3.32 mm, and mean baseline peak systolic velocities were 218.26 and 166.51 cm/s, respectively. Fourteen of 27 children showed persistent triphasic flow in the superficial femoral artery (group 1); 7 children showed altered flow of biphasic (n = 3) or monophasic (n = 4) waveforms (group 2); and 6 children showed pulsus tardus et parvus pattern (group 3) after femoral sheath insertion. Mean baseline diameter of the common femoral artery and mean subtracted value between common femoral artery and femoral sheath size were significantly smaller in group 3 than the other groups. Size discrepancy between common femoral artery and femoral sheath was <1 mm in all cases of group 3. Superficial femoral artery diameter and peak systolic velocity significantly decreased after femoral sheath insertion in group 3 compared to groups 1 and 2. A significant skin temperature drop after sheath insertion in the ipsilateral lower extremity was noted in group 3 (-1.83°C), compared to groups 1 and 2 (+0.42 and -0.86°C, respectively). Changes in the spectral waveforms of superficial femoral arteries frequently occur in children during transfemoral cerebral angiography (13/27, 48%). Significant arterial flow disturbance was noted on Doppler US in children with a common femoral artery <1 mm larger than the femoral sheath diameter.

Regional differences in the cutaneous thermal sensitivity to wetness across the torso (1104.10)

Humans are not provided with humidity receptors and the ability to perceive skin wetness seems to rely on the sensory inputs arising from thermal cold afferents. Given the regional variability in thermal sensitivity across the torso, we examined whether regional differences in the sensitivity to wetness exist. Sixteen male participants were tested at rest. Twelve regions of the torso were stimulated with a dry or wet thermal probe (25cm²) set at a temperature of 15°C below the local skin temperature, which was measured pre and post stimulation. Thermal and wetness sensations were recorded using likert scales. As a result of the same relative cold stimuli, the skin cooling response varied by location and regional differences were found in thermal and wetness sensations. The lateral chest showed the greater drop in local skin temperature. Colder sensations were reported on the lateral abdomen and lower back. Greater wetness was reported on the lower back. No differences were perceived between wet and dry stimuli, the dry ones perceived as wet as the wet ones. The regional variability in wetness sensitivity showed a pattern similar to the thermal sensitivity to cold. We conclude that, as thermal cold afferents seem to have a critical role in driving the perception of wetness, based on the regional variability in thermal sensitivity, humans present regional differences in the cutaneous sensitivity to wetness across the torso.Grant Funding Source: Supported by Loughborough University and Oxylane Research