Heat Sensation Research Articles

Differential Expression and Functionality of TRPA1 Protein Genetic Variants in Conditions of Thermal Stimulation

The role of genetic modifications of the TRPA1 receptor has been well documented in inflammatory and neuropathic pain. We recently reported that the E179K variant of TRPA1 appears to be crucial for the generation of paradoxical heat sensation in pain patients. Here, we describe the consequences of the single amino acid exchange at position 179 in the ankyrin repeat 4 of human TRPA1. TRPA1 wild type Lys-179 protein expressed in HEK cells exhibited intact biochemical properties, inclusive trafficking into the plasma membrane, formation of large protein complexes, and the ability to be activated by cold. Additionally, a strong increase of Lys-179 protein expression was observed in cold (4 °C) and heat (49 °C)-treated cells. In contrast, HEK cells expressing the variant Lys-179 TRPA1 failed to get activated by cold possibly due to the loss of ability to interact with other proteins or other TRPA1 monomers during oligomerization. In conclusion, the detailed understanding of TRPA1 genetic variants might provide a fruitful strategy for future development of pain treatments.

Rheumatoide Arthritis: Diagnostik und Therapie 2012

Rheumatoid Arthritis (RA) should be suspected if patients do not only complain of joint pain, but suffer from joint swelling, sensation of heat, hyperemia and warmth around the joints. An arthritic joint pain should be most prominent at night time or early in the morning and cause morning stiffness (> 30min) of the joint, exercise will improve the symptoms. Diagnosis of RA will be even more likely if wrists, MCP- or PIP joints are affected. Serologic procedures will test for rheumatoid factor or anti-citrullinated antibodies (CCP Ab). One needs to keep in mind that positive results for rheumatoid factor or CCP Ab alone never proves the diagnosis of RA. After diagnosis therapy should be started immediately, recruiting physiotherapy, pain medication, corticosteroids and disease-modifying anti-rheumatic drugs (DMARDs), primarily methotrexate. At the latest after failure of two DMARDs biologics like TNF-α-blockers, an Interleukin-6-Receptor-antibody, a B-cell-specific antibody or a rather T-cell-specific biologic will be initiated. Aim of therapy is freedom of symptoms of an ongoing arthritis, low dosage of immunosuppressants (especially corticosteroids maximally 5mg/day), stop of radiological progression and prevention of long term consequences of inflammation like myocardial infarction, stroke or lymphoma.

Chronic pain after breast augmentation is associated with both signs of peripheral nerve injury and central nervous mechanisms

Abstract Background/aims The mechanisms behind chronic postsurgical pain remains unsettled. Quantitative sensory testing and questioning sensory function may help understand mechanisms behind the transition from acute to chronic pain. The aim of this study was to assess these aspects in postsurgical patients with and without chronic postsurgical pain. Methods 116 women, who answered a questionnaire in a four years follow-up study of pain, sensory changes and quality of life after cosmetic breast augmentation surgery [1], were invited to participate in a psychophysical study. Twenty women answered the request and filled in a questionnaire, and 12 of these women finally met for examination. Results Six of the 12 women had pain in the area of surgery, three were pain-free, but reported sensory changes and three reported no pain or sensory disturbances. We performed a detailed quantitative sensory examination, with a protocol adapted from Rollke et al. [2] While only 3/6 patients in the pain-free group reported hypoesthesia, an area of hypoesthesia to tactile-, heat- and cold stimuli was identified in all subjects when examined (Table 1). Table 1 Number in each group (subjects with pain vs. subjects without pain) showing presence of sensory characteristics. Pain (N = 6) No pain (N = 6) Questionnaire Hypoesthesia 5 3 Hyperesthesia 6 3 Examination Hypoesthesia (tactile, heat, cold) 6 6 Hypersensitivity detected 4 1 Hyperpathia to heat 5 5 Paradoxical heat sensation during cold stimulation 4 0 Allodynia, cotton 0 0 Allodynia, brush 0 1 Cold allodynia 5 1 Abnormal temporal summation 5 1 Deep pain after algometry 4 0 The most striking difference between the group reporting pain and the one not reporting pain was the presence of paradoxical heat sensation, cold allodynia, abnormal temporal summation, and the presence of deep pain during/after pressure pain threshold testing with the algometer in the group with pain. Conclusion Self-reported sensory changes under-estimated sensory changes. Sensory testing revealed signs of peripheral nerve injury changes in all subjects, while signs of central nervous changes were found predominantly in patients with persistent pain.

Comparison of Allergic Adverse Effects and Contrast Enhancement Between Iodixanol and Iopromide

BackgroundIodinated X-ray contrast media are the most commonly used contrast agents in the world with an annual application of 40-50 million. New non-ionic contrast agents are subdivided into low osmolar agents such as iopromide and iso-osmolar agents such as iodixanol. Regarding different biochemical characteristics, these agents are different in the allergic reactions and contrast enhancement and final lesion conspicuity.ObjectivesThis study was carried out to compare allergic adverse effects and contrast enhancement between iodixanol and iopromide.Patients and MethodsOne-hundred and twenty patients who were referred for abdominal CT scan to Besat Hospital were included in this study. Patients were randomly divided into two groups (A and B). Group A received 100 cc iodixanol (300 mgI/mL) and group B received 100 cc iopromide (300 mgI/ml) by power injector. CT examination was performed using Helical CT Scanner (Somatom, Siemens, Germany). Sixty seconds after injection, images were obtained and enhancement of port, liver and aorta were determined. Allergic adverse effects were recorded one hour and up to one week after injection.ResultsIodixanol produced a significantly greater enhancement of the hepatic, aorta and portal vein than iopromide (P < 0.01). Sixty seconds after injection, associated pain and heat sensation were less frequent in iodixanol in comparison with iopromide (P = 0.03). Immediate reactions such as nausea and vomiting were less frequent in iodixanol (P = 0.01). Late skin reactions such as rash was more frequent in iodixanol (P < 0.01).ConclusionsIodixanol is safe and is better tolerated in the early phase of injection with better contrast enhancement and lesion conspicuity. Mild late skin rash is its disadvantage.

BOLD Responses in Somatosensory Cortices Better Reflect Heat Sensation than Pain

The discovery of cortical networks that participate in pain processing has led to the common generalization that blood oxygen level-dependent (BOLD) responses in these areas indicate the processing of pain. Physical stimuli have fundamental properties that elicit sensations distinguishable from pain, such as heat. We hypothesized that pain intensity coding may reflect the intensity coding of heat sensation during the presentation of thermal stimuli during fMRI. Six 3T fMRI heat scans were collected for 16 healthy subjects, corresponding to perceptual levels of "low innocuous heat," "moderate innocuous heat," "high innocuous heat," "low painful heat," "moderate painful heat," and "high painful heat" delivered by a contact thermode to the face. Subjects rated pain and heat intensity separately after each scan. A general linear model analysis detected different patterns of brain activation for the different phases of the biphasic response to heat. During high painful heat, the early phase was associated with significant anterior insula and anterior cingulate cortex activation. Persistent responses were detected in the right dorsolateral prefrontal cortex and inferior parietal lobule. Only the late phase showed significant correlations with perceptual ratings. Significant heat intensity correlated activation was identified in contralateral primary and secondary somatosensory cortices, motor cortex, and superior temporal lobe. These areas were significantly more related to heat ratings than pain. These results indicate that heat intensity is encoded by the somatosensory cortices, and that pain evaluation may either arise from multimodal evaluative processes, or is a distributed process.

Full recovery from CRPS type 1 after introduction of fentanyl transdermal patch: a case report

In Japan, use of the fentanyl transdermal patch was finally approved in 2010 for the treatment of intractable pain. Complex regional pain syndrome (CRPS) is one of the diseases/syndromes associated with pain that is often difficult to diagnose and treat. We report a case of CRPS type 1 which was refractory to prior treatments administered at several institutions, but introduced to resolve after initiation of treatment with the fentanyl transdermal patch. The patient was a 54-year-old woman. After 2 sites surgery, spinal decompression and fixation of L4/5 and L3/4, she began to suffer from bilateral numbness and coldness over the region extending from the lateral femur to the crus, as well as severe pain and heat sensation in the right sole. Bilateral thermal distance was 10 degrees. Although various treatments, including drug therapy, were administered at some clinics, the visual analog scale (VAS) score remained at approximately 70 mm. For seven months since her initial visit to closely our outpatient pain clinic, she was treated by several blocks along with rehabilitation therapy. However, the VAS score only decreased to 50 to 60 mm, and no further relief of symptoms could be obtained. Then, use of the fentanyl transdermal patch was initiated at the dose of 2.1 mg. This resulted in a dramatic reduction of the VAS score to 0 to 10 mm within 1 week, and the symptoms were relieved within 3 weeks to the level of no difference in the temperature of lower extremities. After two months the treatment was discontinued altogether according to the patient's wishes, however, no sign of CRPS recurrence has been observed at the present time. In this case, the course to the introduction of the fentanyl transdermal patch may also be important as a part of multidisciplinary treatment.

Mushroom-Body Memories: An Obituary Prematurely Written?

Studies on insect olfactory learning have established the mushroom bodies as key brain structures for the formation of long-term memory (LTM). Two new neurons in the fly brain are reported now as essential sites for LTM formation, while mushroom bodies are claimed to be unnecessary to this end.

Low fluence–high repetition rate diode laser hair removal 12‐month evaluation: Reducing pain and risks while keeping clinical efficacy

High fluence diode lasers with contact cooling have emerged as the mainstay modality for hair removal. However, the use of these devices is associated with pain and side effects, especially in patients with dark or tanned skin. A novel concept of depilation at low fluence using 810 nm diode laser has been introduced as a solution to these shortcomings. The purpose of this study was to evaluate the lasting efficacy and safety of low-level fluence 810 nm (15 J/cm(2) ) and high repetition rate (5 Hz) F1 Diode Laser™ therapy on hair reduction in patients with various skin types. This randomised, controlled, bilaterally paired within-patient, double-blind study compared low level fluence 810 nm (15 Joules/cm(2) ) laser diode therapy to nontreated shaved control areas on long-term hair reduction. Seventeen patients with skin type II-V were treated four times at 1 month intervals. Hair count was assessed monthly over 10 months using an objective computerised method. Safety and tolerability were assessed by adverse reactions monitoring. Statistically significant differences in hair count between treated and control sites were observed at each follow-up visit. The majority of patients reported a slight but bearable sensation of heat during the laser treatment, and transient erythema post-treatment. This study showed that laser hair removal with the F1 Diode Laser™ system was generally well tolerated, safe, and efficacious in this small sample study of patients with various skin types. After just four treatments, permanent hair reduction following one complete hair cycle has been shown. Controlled studies on larger groups of patients within each skin phototype are needed to confirm these promising results.

A randomised controlled trial comparing rocuronium priming, magnesium pre‐treatment and a combination of the two methods*

We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety-two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg(-1) rocuronium; patients in the prime group were given 0.06 mg.kg(-1) rocuronium three minutes before a further dose of 0.54 mg.kg(-1) rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg(-1) magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16)s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid-sequence intubating conditions, compared with either magnesium sulphate or priming used alone.

Functional connectivity of pain-mediated affect regulation in Borderline Personality Disorder.

Affective instability and self-injurious behavior are important features of Borderline Personality Disorder. Whereas affective instability may be caused by a pattern of limbic hyperreactivity paired with dysfunctional prefrontal regulation mechanisms, painful stimulation was found to reduce affective arousal at the neural level, possibly underlying the soothing effect of pain in BPD.We used psychophysiological interactions to analyze functional connectivity of (para-) limbic brain structures (i.e. amygdala, insula, anterior cingulate cortex) in Borderline Personality Disorder in response to painful stimulation. Therefore, we re-analyzed a dataset from 20 patients with Borderline Personality Disorder and 23 healthy controls who took part in an fMRI-task inducing negative (versus neutral) affect and subsequently applying heat pain (versus warmth perception).Results suggest an enhanced negative coupling between limbic as well as paralimbic regions and prefrontal regions, specifically with the medial and dorsolateral prefrontal cortex, when patients experienced pain in addition to emotional arousing pictures. When neutral pictures were combined with painful heat sensation, we found positive connectivity in Borderline Personality Disorder between (para-)limbic brain areas and parts of the basal ganglia (lentiform nucleus, putamen), as well areas involved in self-referential processing (precuneus and posterior cingulate).We found further evidence for alterations in the emotion regulation process in Borderline Personality Disorder, in the way that pain improves the inhibition of limbic activity by prefrontal areas. This study provides new insights in pain processing in BPD, including enhanced coupling of limbic structures and basal ganglia.

The Interruptive Effect of Pain on Attention

Pain is known to disrupt attentional performance in both healthy adults and patients with chronic pain. Exactly which aspects of attentional function are affected are, however, still to be determined. The primary aim of this investigation was to systematically examine the effects of experimentally induced pain on a range of attentional performance tasks. Following a review of tests of attentional disruption, seven best candidate tasks were selected and examined across seven experiments. The tasks were: continuous performance, flanker, endogenous precueing, n-back, inhibition, attentional switching, and divided attention. Healthy adult participants performed each of these tasks under three different conditions: a painful heat sensation, a warm heat sensation, and a nonheat control. Pain differentially affected attentional performance across these tasks; pain-related attentional impairment was found on the n-back, attentional switching, and divided attention tasks, but not on the other tasks. This finding suggests that the aspects of attention most affected by pain are those essential for the completion of complex tasks that require the processing of multiple cues and control over attentional deployment. These results are discussed in the context of an emerging view of pain as a demand for executive control and the development of measures that could be used to examine attentional disruption in the context of pain.

Heteromeric Heat-sensitive Transient Receptor Potential Channels Exhibit Distinct Temperature and Chemical Response

TRPV1 and TRPV3 are two heat-sensitive ion channels activated at distinct temperature ranges perceived by human as hot and warm, respectively. Compounds eliciting human sensations of heat or warmth can also potently activate these channels. In rodents, TRPV3 is expressed predominantly in skin keratinocytes, whereas in humans TRPV1 and TRPV3 are co-expressed in sensory neurons of dorsal root ganglia and trigeminal ganglion and are known to form heteromeric channels with distinct single channel conductances as well as sensitivities to TRPV1 activator capsaicin and inhibitor capsazepine. However, how heteromeric TRPV1/TRPV3 channels respond to heat and other stimuli remains unknown. In this study, we examined the behavior of heteromeric TRPV1/TRPV3 channels activated by heat, capsaicin, and voltage. Our results demonstrate that the heteromeric channels exhibit distinct temperature sensitivity, activation threshold, and heat-induced sensitization. Changes in gating properties apparently originate from interactions between TRPV1 and TRPV3 subunits. Our results suggest that heteromeric TRPV1/TRPV3 channels are unique heat sensors that may contribute to the fine-tuning of sensitivity to sensory inputs.

Responses of Obese and Non-obese Boys Cycling in the Heat

This study compared rectal temperature (Tre), heat sensation and sweating between obese and non-obese boys during cycling in the heat. Participants (aged 12-15 years) were 17 obese and 16 non-obese (BMI=29.4±4.3 and 16.8±1.7 kg · m⁻², respectively) boys. They cycled for 30-min (50-55% VO(2peak)) in a climatic chamber (35°C, 45% RH) and Tre, heat sensation and sweat volume were monitored. From the start to the end of cycling, Tre was similar between the obese (37.4±0.3-37.8±0.3°C) and non-obese (37.3±0.2-37.9±0.2°C) groups. Heat sensation was higher in the obese group from the start (3.6±2.7 vs. 1.3±1.4 cm; P=0.008) to the end (7.6±2 vs. 5.2±2.2 cm; P=0.003) of cycling. Sweat volume corrected by body surface area was similar between the obese (200±123 mL · m⁻²) and non-obese (212±80 mL · m⁻²) groups. Initial and final HR were similar in both groups, and RPE was higher in the obese group at 25th (P=0.040) and 30th (P=0.019) min. In conclusion, the obese pubescent participants presented similar Tre and sweating volume, but higher heat sensation while cycling in the heat.

スポーツにおける「あがり」の要因と要因間の関係性

Factors related to choking under pressure during sports were investigated through a questionnaire survey, and the relationships among them were examined. A questionnaire survey of choking was conducted among university students in sports-oriented school clubs (n=535). Exploratory factor analysis extracted 11 factors: changes in motor control and vicious circles, abnormal physical sensations, cognitive and perceptual confusion, introversion, self-consciousness, feelings of physical heaviness and weakness, conscious processing (attention to movements), passivity, feelings of physical fatigue, safety-oriented strategies, and heat sensations. An analytical model with nine factors (excluding feelings of physical fatigue and heat sensations) as latent variables was constructed, and covariance structure analysis was performed. The results indicated the validity of the mechanistic model of choking, consisting of nine latent variables. According to the model, when self-consciousness, or abnormal physical sensations, had a high profile, conscious processing increased. Furthermore, it was confirmed that conscious processing affected changes in motor control and vicious circles, which led directly to a decline in motor performance. It was also indicated that abnormal physical sensations determined cognitive and perceptual confusion, or feelings of physical heaviness and weakness. On the other hand, when cognitive and perceptual confusion and feelings of physical heaviness and weakness had a high profile, passivity increased. High passivity caused changes in motor control and vicious circles. Moreover, increased passivity led to the adoption of a safety-oriented strategy that often caused changes in motor control and vicious circles. While previous studies have tried to explain choking only from the perspective of changes in attention, the above results suggest the following mechanistic model of choking, indicative of another perspective: changes in psychological, physiological, and behavioral variables cause a decline in performance. Especially interactions between emotions and cognition and the adoption of a strategy with a low risk of failure determine changes in motor control.

Heteromeric Heat-Sensitive TRP Channels Exhibit Distinct Temperature and Chemical Response

TRPV1 and TRPV3 are two heat-sensitive channels activated at distinct temperature ranges perceived by human as hot and warm, respectively. Compounds eliciting human sensations of heat or warmth can also potently activate them. While in rodents TRPV3 is expressed predominantly in keratinocytes, in humans TRPV1 and TRPV3 are co-expressed in sensory neurons of dorsal root ganglia and trigeminal ganglion and are known to form heteromeric channels with distinct single-channel conductances as well as sensitivities to TRPV1 activator and inhibitor. However, how heteromeric TRPV1/TRPV3 channels respond to heat and other stimuli remains unknown. In the present study, we examined the behavior of heteromeric TRPV1/TRPV3 channels activated by heat, capsaicin and voltage. Our results demonstrate that the heteromeric channels exhibit distinct temperature sensitivity, activation threshold, and heat-induced sensitization. Changes in gating properties apparently originate from interactions between TRPV1 and TRPV3 subunits. Furthermore, biochemical study demonstrated interactions between the intracellular C termini of TRPV1 and TRPV3, indicating that the recently identified tetrameric assembly domain for homomeric channels also mediates heteromeric subunit assembly. Together, our results suggest that heteromeric TRPV1/TRPV3 channels may contribute to the fine tuning of sensitivity to sensory inputs and pain.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Aspects of Applying Ergonomic Tests in the Evaluation of Ballistic Body Armours Using the Example of Ballistic Vests

The main objective of using ballistic protection (such as ballistic vests) is to protect the human body from mechanical damage. In Poland, the requirements for ballistic vests and ballistic inserts are set out in PN-V 87000:2011 Light ballistic armour. Bullet-proof and fragmentation vests Requirements and tests. This standard lays particular emphasis on the quality of workmanship of the vest etc, ergonomics aspects are treated marginally. At the same time, the use of any elements that cover the body affects the process of heat exchange between the human body and the environment, and can cause thermal strain while performing various tasks which can affect the accuracy of user’s actions. Hence it is important to determine the level of their impact on the physiological and psychological reactions of the vest user. In this paper the results of comprehensive ergonomic tests of ballistic armour are analyzed and an example of this type of research methodology, covering important aspects of the functioning of the body under strain conditions of effort and a thermal environment is presented. In order to conduct a broad assessment of the ergonomic aspects for selected vests, the following measurements were performed: thermal insulation of uniforms and vests; based on the result, a temperature range was determined in which the vests should be used in order to avoid negative heat sensations for the user; the impact of vests on physiological indicators of users; work comfort in vests, in laboratory and field tests; influence of vests on human psychological parameters.

Anterior inferior cerebellar artery syndrome; without hearing loss

The anterior inferior cerebellar artery (AICA) arises from the lower side of the basilar artery and supplies blood to the rostral olfactory bulb, rostral pontine base, and cerebellar regions. The AICA syndrome was first defined by Adams in 1943. Here, we present a case of a patient with a left AICA occlusion who suddenly started experiencing dizziness and had abnormal gait; he was subsequently diagnosed with ischemia in the left cerebellar hemisphere.A 55-year-old man was admitted to the hospital with complaints of sudden onset of vertigo, speech disorder, and imbalance. The neurological examination revealed gait disturbance, and left-sided ataxia. In addition, dysarthric speech left peripheral facial paralysis, loss of pain and heat sensations in the left half of the face and right half of the body. Bilateral horizontal nystagmus was observed. Babinski and Hoffman signs were also observed on the left side. The patient was evaluated with diffusion weighted (DW) magnetic resonance (MR) imaging. On DW image and apparent diffusion coefficient (ADC) maps precisely determined diffusion restrictions in the antero-inferior part of the left cerebellar hemisphere and the left part of the inferior vermis. MR angiography revealed occlusions in the right internal carotid artery and left AICA; hence, he was administered antiagregan treatment. We have presented this case because infarctions in the AICA have different clinical features from those observed in other cerebellar arteries, and such cases are rarely observed in neurological practice.

Feeling the heat: Temperature sensing by ion channels – how do they do it?

Two ion channels, TRPV1 (capsaicin receptor/channel) and TRPM8 (menthol receptor channel) of the transient receptor potential (TRP) family, are well established as mediators of heat and cold sensation respectively. What is it about the structures of these molecules that enables these properties?

Psychophysical and cerebral responses to heat stimulation in patients with central pain, painless central sensory loss, and in healthy persons

Patients with central pain (CP) typically have chronic pain within an area of reduced pain and temperature sensation, suggesting an impairment of endogenous pain modulation mechanisms. We tested the hypothesis that some brain structures normally activated by cutaneous heat stimulation would be hyperresponsive among patients with CP but not among patients with a central nervous system lesion causing a loss of heat or nociceptive sensation with no pain (NP). We used H 2 15O positron emission tomography to measure, in 15 healthy control participants, 10 NP patients, and 10 CP patients, increases in regional cerebral blood flow among volumes of interest (VOI) from the resting (no stimulus) condition during bilateral contact heat stimulation at heat detection, heat pain threshold, and heat pain tolerance levels. Both patient groups had a reduced perception of heat intensity and unpleasantness on the clinically affected side and a bilateral impairment of heat detection. Compared with the HC group, both NP and CP patients had more hyperactive and hypoactive VOI in the resting state and more hyperresponsive and hyporesponsive VOI during heat stimulation. Compared with NP patients, CP patients had more hyperresponsive VOI in the intralaminar thalamus and sensory–motor cortex during heat stimulation. Our results show that focal CNS lesions produce bilateral sensory deficits and widespread changes in the nociceptive excitability of the brain. The increased nociceptive excitability within the intralaminar thalamus and sensory–motor cortex of our sample of CP patients suggests an underlying pathophysiology for the pain in some central pain syndromes.

Analysis of Internet Bar Use Evaporative Air-Conditioning and Ventilation of Thermal Comfort

The factors affecting indoor thermal environment are briefly introduced in this article, and one Internet bar was tested and analyzed that used evaporative air-conditioning in lanzhou, gansu. Meanwhile, through the air temperature, the relative humidity and air velocity of sensitivity factors were analyzed that heat sensation to human body, changed the heat sensation for people's from qualitative to the quantitative. As one way and the basis has provided for the improvement room internal heat environment quality.