127 research outputs found
Neurophysiology of Skin Thermal Sensations
No full textUndoubtedly, adjusting our thermoregulatory behavior represents the most effective mechanism to maintain thermal homeostasis and ensure survival in the diverse thermal environments that we face on this planet. Remarkably, our thermal behavior is entirely dependent on the ability to detect variations in our internal (i.e., body) and external environment, via sensing changes
in skin temperature and wetness. In the past 30 years, we have seen a significant expansion of our understanding of the molecular, neuroanatomical, and neurophysiological mechanisms that allow humans to sense temperature and humidity. The discovery of temperature-activated ion
channels which gate the generation of action potentials in thermosensitive neurons, along with the characterization of the spino-thalamo-cortical thermosensory pathway, and the development of neural models for the perception of skin wetness, are only some of the recent advances which have provided incredible insights on how biophysical changes in skin temperature and wetness
are transduced into those neural signals which constitute the physiological substrate of skin thermal and wetness sensations. Understanding how afferent thermal inputs are integrated and how these contribute to behavioral and autonomic thermoregulatory responses under normal brain function is
critical to determine how these mechanisms are disrupted in those neurological conditions, which see the concurrent presence of afferent thermosensory abnormalities and efferent thermoregulatory
dysfunctions. Furthermore, advancing the knowledge on skin thermal and wetness sensations is crucial to support the development of neuroprosthetics. In light of the aforementioned text, this review will focus on the peripheral and central neurophysiological mechanisms underpinning skin thermal and wetness sensations in humans
Humidity sensation, cockroaches, worms and humans: are common sensory mechanisms for hygrosensation shared across species?
No full textAlthough the ability to detect humidity (i.e. hygrosensation) represents an important sensory attribute in many animal species (including humans), the neurophysiological and molecular bases of such sensory ability remain largely unknown in many animals. Recently, Russell and colleagues (Russell J, Vidal-Gadea AG, Makay A, Lanam C, Pierce-Shimomura JT. Proc Natl Acad Sci U S A 111: 8269-8274, 2014) provided for the first time neuromolecular evidence for the sensory integration of thermal and mechanical sensory cues which underpin the hygrosensation strategy of an animal (i.e. the free-living roundworm Caenorhabditis elegans) which lacks specific sensory organs for humidity detection (i.e. hygroreceptors). Due to the remarkable similarities in the hygrosensation transduction mechanisms used by hygroreceptor-provided (e.g. insects) and hygroreceptor-lacking species (e.g. roundworms and humans), Russell and colleagues' findings highlight potentially universal mechanisms for humidity detection which could be shared across a wide range of species, including humans
Radiofrequency Y-V anoplasty in the treatment of anal stenosis
No full textBACKGROUND: Anal stenosis is a common proctologic disease often caused from hemorrhoids surgery. Treatments adopted are many and varied. In this study we applied radiofrequencies to the classic Y-V anoplasty operation and reported results obtained.
METHODS: Eligibility criteria consisted of patients affected by anal stenosis. Exclusion criteria were those with contraindications to the surgical operation: pregnant patients or American Society of Anaesthesiologists Score III or IV.
RESULTS: From January 2002 to December 2004 we operated 7 patients, 4 of them were males. Mean age at the time of diagnosis was 46 years. All patients referred obstructive defecation, painful evacuation or bleeding. Mean values for operative time were 30 min. Postoperative pain was 3.9 at day 1 and 3.0 at 7th day (VAS scale). Patient satisfaction rate was 6.6 at three weeks and 8.3 at 6 and 12 months. No recurrences were observed after 1 year.
CONCLUSION: Radiofrequency Y-V anoplasty is a feasible and effective for the treatment of anal stenosis. The radiofrequency bistoury easies the procedure, lessens operating times and the healing process of surgical wounds
A meta-analytic approach to ilioinguinal nerve excision or preservation during open inguinal hernia repair
No full textNo abstrac
Clinical applications of radiofrequency in proctology: A review
No full textThe radiofrequency scalpel is an innovative instrument which allows to cut and coagulate tissues in an atraumatic manner, conversely to the electric scalpel. The authors describe the use of radiofrequencies in proctology by making a literature review for every major proctologic disease (hemorrhoids, anal fistulas, anal fissure, sinus pilonidalis, hypertrophied anal papillae). Many techniques have been developed with radiofrequencies in hemorrhoids treatment: coagulation, ablation with plication, Milligan Morgan and Parks hemorrhoidectomy. In the treatment of anal fissures, radiofrequency subcutaneous lateral internal sphincterotomy has been described. For anal fistulas, both radiofrequency fistulotomy and fistulectomy. Finally, radiofrequency sinotomy for sinus pilonidalis and coagulation for hypertrophied anal papillae are present in literature. The analysis of the results obtained with radiofrequency surgery compared with those of the "classic" surgery for proctologic disease shows that in most of them radiosurgery facilitates, accelerates and improves the surgical procedure
Beneficial effects of Flavonoids after ambulatory therapy with Combined Hemorrhoidal Radiocoagulation (CHR)
No full textBackground: Phlebotropic activity, protective effect on the capillaries and anti-inflammatory properties of the Flavonoids have been reported in literature. Recently, we evaluated the effect of these drugs in controlling postoperative symptoms of proctologic surgery. In this randomized study we compared the results obtained in two groups of patients, with grade II haemorrhoids, submitted to radiofrequency coagulation of the hemorrhoidal nodule with radiofrequency scalpel (CHR), to verify the effects of Flavonoids to reduce further symptoms after treatment.
Materials and Methods: Out of 70 patients initially randomized, a total of 59 patients regularly returned to outpatient visit at least for 1 month of follow-up. Consequently, two groups of patients were considered: Group A, represented by 28 individuals treated with Flavonoids, and Group B, consisting of 31 patients as a control group. Our purpose was to determine: grade of pain after procedure and at first evacuation (score from 1 to 10), bleeding, incidence of failures and complications, patient’s satisfaction after 30 days from the treatment (score from 1 to 10).
Results: We observed that the results obtained regarding the pain reported at the end of procedures (2.51 ± 1.4 for group A and 2.54 ± 1.15 for group B) and at the first evacuation (2.6 ±.1.52 for group A and 2.7 ± 1.18 for group B) are similar in both study groups. Instead, the mean score on overall satisfaction at 30 days from the treatment showed a statistical significance (8.32 ± 1.72 for group A and 6.64 ± 1.78 for group B; p <0.05).There were no reported other important issues.
Conclusions: Our results confirm the usefulness of Flavonoids to make more comfortable the post-treatment period
Characteristics of the local cutaneous sensory thermo-neutral zone
No full textSkin temperature detection thresholds have been used to measure human cold and warm sensitivity across the temperature continuum. They exhibit a sensory zone within which neither warm nor cold sensations prevail. This zone has been widely assumed to coincide with steady-state local skin temperatures between 32 and 34°C, but its underlying neurophysiology has been rarely investigated. In this study we employ two approaches to characterize the properties of sensory thermoneutrality, testing for each whether neutrality shifts along the temperature continuum depending on adaptation to a preceding thermal state. The focus is on local spots of skin on the palm. Ten participants (age: 30.3 ± 4.8 yr) underwent two experiments. Experiment 1 established the cold-to-warm inter-detection threshold range for the palm’s glabrous skin and its shift as a function of 3 starting skin temperatures (26, 31, or 36°C). For the same conditions, experiment 2 determined a thermally neutral zone centered around a thermally neutral point in which thermoreceptors’ activity is balanced. The zone was found to be narrow (~0.98 to ~1.33°C), moving with the starting skin temperature over the temperature span 27.5–34.9°C (Pearson r = 0.94; P < 0.001). It falls within the cold-to-warm inter-threshold range (~2.25 to ~2.47°C) but is only half as wide. These findings provide the first quantitative analysis of the local sensory thermoneutral zone in humans, indicating that it does not occur only within a specific range of steady-state skin temperatures (i.e., it shifts across the temperature continuum) and that it differs from the inter-detection threshold range both quantitatively and qualitatively. These findings provide insight into thermoreception neurophysiology
The Zuckerkandl tubercle
No full textIdentification and preservation of the recurrent laryngeal nerve is a major concern during thyroidectomies. The Zuckerkandl tubercle is an anatomic landmark that can be used for this purpose. It is generally found in 63% to 80% of patients undergoing thyroidectomy and is located between the superior and inferior lobes and points toward the tracheoesophageal groove. It is classified into three grades according to size: I 1 cm. A grade III tubercle, present in 45% of patients, is sometimes associated with significant pressure symptoms in otherwise small-sized goiters
Use of Flavonoids for the treatment of symptoms after hemorrhoidectomy with radiofrequency scalpel
No full textOBJECTIVES: Control of postoperative symptoms is of paramount importance in proctologic surgery. Phlebotropic activity, protective effect on the capillaries and anti-inflammatory properties of the flavonoids have been reported in several studies. They have been used to treat a variety of conditions including chronic venous insufficiency, lymphedema and hemorrhoids. Numerous trials, assessing the effect of phlebotonics in treating the symptoms and signs of haemorrhoidal disease, suggest that there is a potential benefit. Our trial was conducted to evaluate whether the flavonoids reduce postoperative bleeding, pain and other symptoms after hemorrhoidectomy.
PATIENTS AND METHODS: We compared the results obtained in 24 patients undergoing open hemorrhoidectomy with radiofrequency scalpel. Our study cohort was randomized in two groups: the Group A received flavonoids in the postoperative period, the Group B has constituted the control group, without administration of study drug. Follow-up outpatient visits were performed on 7, 15 and 30 postoperative day (POD). During the visits the patients expressed trough a list of specific questions, based on a scoring system (1 to 10), their opinion about the extent of postoperative symptoms as pain, bleeding, tenesmus, pruritus and perianal weight.
RESULTS: We observed that the results obtained after 7 days of surgery are similar in both study groups. Even after 15 and 30 days no significant changes were observed between the two groups about pain and bleeding. Instead, we observed significant differences regarding tenesmus (group A: 8.0 +/- 1.1 vs Group B: 5.4 +/- 1.5 at 15 POD, p < 0.05; group A: 9.1 +/- 0.8 vs Group B: 5.7 +/- 0.9 at 30 POD, p < 0.05), pruritus (group A: 7.1 +/- 1.4 vs Group B: 4.8 +/- 1 at 15 POD, p < 0.05; group A: 9.5 +/- 0.5 vs Group B: 6.6 +/- 0.8 at 30 POD, p < 0.05) and perianal weight (group A: 7.2 +/- 0.9 vs Group B: 6.2 +/- 0.8 at 15 POD, p < 0.05; group A: 9.75 +/- 0.4 vs Group B: 7.3 +/- 0.9 at 30 POD, p < 0.05).
CONCLUSIONS: Our results confirm the usefulness of this drug to reduce the prevalence and the importance of post-hemorrhoidectomy symptoms and make more comfortable the postoperative period
Thermosensory mapping of skin wetness sensitivity across the body of young males and females at rest and following maximal incremental running
No full textKey points: Humans lack skin receptors for wetness (i.e. hygroreceptors), yet we present a remarkable wetness sensitivity. Afferent inputs from skin cold-sensitive thermoreceptors are key for sensing wetness; yet, it is unknown whether males and females differ in their wetness sensitivity across their body and whether high intensity exercise modulates this sensitivity. We mapped sensitivity to cold, neutral and warm wetness across five body regions and show that females are more sensitive to skin wetness than males, and that this difference is greater for cold than warm wetness sensitivity. We also show that a single bout of maximal exercise reduced the sensitivity to skin wetness (i.e. hygro-hypoesthesia) of both sexes as a result of concurrent decreases in thermal sensitivity. These novel findings clarify the physiological mechanisms underpinning this fundamental human sensory experience. In addition, they indicate sex differences in thermoregulatory responses and will inform the design of more effective sport and protective clothing, as well as thermoregulatory models. Abstract: Humans lack skin hygroreceptors and we rely on integrating cold and tactile inputs from A-type skin nerve fibres to sense wetness. Yet, it is unknown whether sex and exercise independently modulate skin wetness sensitivity across the body. We mapped local sensitivity to cold, neutral and warm wetness of the forehead, neck, underarm, lower back and dorsal foot in 10 males (27.8 ± 2.7 years; 1.92 ± 0.1 m2 body surface area) and 10 females (25.4 ± 3.9 years; 1.68 ± 0.1 m2 body surface area), at rest and post maximal incremental running. Participants underwent our quantitative sensory test where they reported the magnitude of thermal and wetness perceptions (visual analogue scale) resulting from the application of a cold (5°C below skin temperature) wet (0.8 mL of water), neutral wet and warm wet (5°C above skin temperature) thermal probe (1.32 cm2) to five skin sites. We found that: (i) females were ∼14% to ∼17% more sensitive to cold-wetness than males, yet both sexes were as sensitive to neutral- and warm-wetness; (ii) regional differences were present for cold-wetness only, and these followed a craniocaudal increase that was more pronounced in males (i.e. the foot was ∼31% more sensitive than the forehead); and (iii) maximal exercise reduced cold-wetness sensitivity over specific regions in males (i.e. ∼40% decrease in foot sensitivity), and also induced a generalized reduction in warm-wetness sensitivity in both sexes (i.e. ∼4% to ∼6%). For the first time, we show that females are more sensitive to cold wetness than males and that maximal exercise induce hygro-hypoesthesia. These novel findings expand our knowledge on sex differences in thermoregulatory physiology
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