Volar Forearm Research Articles

Absence of flexor carpi radialis identified during volar approach for fixation of distal radius fracture: a case report

BackgroundVolar locking plate fixation of distal radius fractures is commonly performed because of its good clinical outcomes. The flexor carpi radialis (FCR) approach is one of the most popular approaches to dissecting the volar side of the distal radius because of its simplicity and safety. We describe an extremely rare case of an absent FCR identified during a volar approach for fixation of a distal radius fracture.Case presentationA 59-year-old woman with distal radius fracture underwent surgery using the usual FCR approach and volar locking plate. We could not identify the absence of the FCR tendon preoperatively because of severe swelling of the distal forearm. At first, we wrongly identified the palmaris longus tendon as the FCR because it was the tendinous structure at the most radial location of the volar distal forearm. When we found the median nerve just radial to the palmaris longus tendon, we were then able to identify the anatomical abnormality in this case. To avoid iatrogenic neurovascular injuries, we changed the approach to the classic Henry’s approach.ConclusionsAlthough the FCR approach is commonly used for fixation of distal radius fractures because of its simplicity and safety, this is the first report of complete absence of the FCR during the commonly performed volar approach for fixation of a distal radius fracture, to our knowledge. Because the FCR is designated as a favorable landmark because of its superficially palpable location, strong and thick structure, and rare anatomical variations, there is the possibility of iatrogenic complications in cases of the absence of the FCR. We suggest that surgeons should have a detailed knowledge of the range of possible anomalies to complete the fixation of a distal radius fracture safely.

Pharmacological validation of a novel nonhuman primate measure of thermal responsivity with utility for predicting analgesic effects.

IntroductionThe development of novel analgesics to treat acute or chronic pain has been a challenge due to a lack of translatable measurements. Preclinical end points with improved translatability are necessary to more accurately inform clinical testing paradigms, which may help guide selection of viable drug candidates.MethodsIn this study, a nonhuman primate biomarker which is sensitive to standard analgesics at clinically relevant plasma concentrations, can differentiate analgesia from sedation and utilizes a protocol very similar to that which can be employed in human clinical studies is described. Specifically, acute heat stimuli were delivered to the volar forearm using a contact heat thermode in the same manner as the clinical setting.ResultsClinically efficacious exposures of morphine, fentanyl, and tramadol produced robust analgesic effects, whereas doses of diazepam that produce sedation had no effect.ConclusionWe propose that this assay has predictive utility that can help improve the probability of success for developing novel analgesics.

Epidermal barrier and oxidative stress parameters improve during in 311 nm narrow band UVB phototherapy of plaque type psoriasis

BackgroundPsoriasis is a multi-systemic inflammatory disease that results from dysregulation between epidermal keratinocyte homeostasis and both innate and acquired immunity. Epidermal barrier defect has been described in psoriatic lesions. Furthermore an imbalance between pro-oxidative stress and antioxidant defense mechanisms are known in psoriasis patients. AimThe aim of this study was to address the link between disease activity, epidermal barrier and systemic oxidative stress in the course of 311 nm narrow band ultraviolet B (NB-UVB) therapy of psoriasis. The dynamic of systemic oxidative stress parameters as well as local transepidermal water loss (TEWL) and stratum corneum hydration (SCH) was characterized before and after 311 nm NB-UVB therapy on the plaques of psoriasis vulgaris in comparison to untreated non-affected volar forearm sites of the same patients. Material and methods22 patients with plaque type psoriasis vulgaris and 25 gender- and age-matched healthy controls were enrolled. We assessed the psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI) for monitoring disease activity, severity and self-perceived DLQI impact as patient related outcome parameter. We measured non-invasively TEWL (Tewameter TM 300) and SCH (Corneometer CM 825) and the end product of lipid peroxidation – malondialdehyde (MDA), Reactive oxygen species (ROS), ascorbyl radicals (Asc) and detoxifying activity of catalase (CAT) were measured in the peripheral blood with spectrophotometric and EPR spectroscopy methods. ResultsDisease activity improved in all patients compared to baseline witnessed by significant decrease in PASI; (from 14.1 to 10.4; p < 0.0001) and DLQI (from 11.7 to 8.1; p < 0.0001). At baseline TEWL-values were significantly (p < 0.0001) higher on psoriatic plaques (16.8 g/h/m2) in comparison to uninvolved skin (5.3 g/h/m2); with a decrease at both sites after NB-UVB phototherapy. SCH was significantly lower at psoriatic plaque s (4.7AU) compared to uninvolved sskin (42.4AU) and increased after treatment (8.6AU) (p < 0.0001). Interestingly, SCH decrease slightly during therapy at uninvolved skin (40.6AU). ROS and Asc declined during therapy in parallel to a decrease in MDA. A mild decrease in the antioxidative enzyme CAT activity which did not reach the significance was observed. ConclusionThe presented data is shows that a clinical improvement of psoriatic plaques under NB-UVB therapy, shown in with a decreased PASI and reflected by an increase in quality of life has beneficial effects on epidermal barrier function, SCH and improvement of systemic oxidative stress parameters (ROS, MDA and Asc). We assume that the general improvement in the oxidative stress parameters along with epidermal barrier parameters reflects mainly the improvement of disease activity which overwrites the possible negative pro-oxidative effects of the UV treatment.

Age-related morphological changes of the dermal matrix in human skin documented in vivo by multiphoton microscopy.

Two-photon fluorescence (TPF) and second harmonic generation (SHG) microscopy provide direct visualization of the skin dermal fibers in vivo. A typical method for analyzing TPF/SHG images involves averaging the image intensity and therefore disregarding the spatial distribution information. The goal of this study is to develop an algorithm to document age-related effects of the dermal matrix. TPF and SHG images were acquired from the upper inner arm, volar forearm, and cheek of female volunteers of two age groups: 20 to 30 and 60 to 80 years of age. The acquired images were analyzed for parameters relating to collagen and elastin fiber features, such as orientation and density. Both collagen and elastin fibers showed higher anisotropy in fiber orientation for the older group. The greatest difference in elastin fiber anisotropy between the two groups was found for the upper inner arm site. Elastin fiber density increased with age, whereas collagen fiber density decreased with age. The proposed analysis considers the spatial information inherent to the TPF and SHG images and provides additional insights into how the dermal fiber structure is affected by the aging process.

UVB- and NGF-induced cutaneous sensitization in humans selectively augments cowhage- and histamine-induced pain and evokes mechanical hyperknesis.

Exaggerated itch responses to pruritic chemical provocations and mechanical stimuli are evident in patients with chronic itch, for example, in atopic dermatitis. Currently used human models of itch do not account for such itch sensitization features, and the mechanisms underlying clinical itch sensitization are unknown. This study utilized two established human models of cutaneous nociceptive sensitization to explore how pre-established inflammatory hyperalgesia (ultraviolet-B-irradiation; "UVB") and non-inflammatory neurotrophic pain sensitization (nerve growth factor; "NGF") alter sensitivity to chemical and mechanically evoked itch. Twenty healthy volunteers participated in the UVB experiment. Six volar forearm areas (2cm diameter) were UVB irradiated with ≤2×minimal erythemal dose, and two non-irradiated areas were used as controls. Sixteen healthy volunteers participated in the NGF experiment and had 2μg intradermally injected (4×50μL in 2cm diameter areas) into both volar forearms. Isotonic saline was applied as control. Pain sensitivity measurements (mechanical and heat pain thresholds) were conducted to validate the models. Subsequently, itch was evoked using histamine and cowhage spicules in the sensitized skin areas, and itch/pain was rated using visual analogue scales. Mechanical hyperknesis (increased itch to punctuate stimuli) was probed with von Frey filaments before/after each itch provocation. Both UVB- and NGF models induced robust primary mechanical hyperalgesia (P<.01) and hyperknesis (P<.05). Neither of the models augmented itch in response to chemical itch provocations but significant increases specifically for pain ratings were observed for both histamine and cowhage (P<.05). This suggests that these models are of limited value as proxies for itch sensitization to pruritogens observed, e.g., in inflammatory dermatoses.

Preoperative Pain Sensitization Is Associated With Postoperative Pillar Pain After Open Carpal Tunnel Release.

Postoperative pillar pain (deep-seated wrist pain worsened by leaning on the heel of the hand) sometimes occurs after carpal tunnel release (CTR), leading to weakness in the hand and delayed return to work. Increased pain sensitivity has been found to be associated with worse symptoms and poorer treatment response in a number of chronic musculoskeletal conditions, but few studies have investigated the association of pain sensitization with pillar pain after CTR. (1) Is preoperative pain sensitization in patients with carpal tunnel syndrome (CTS) associated with increased severity of pillar pain after open CTR? (2) What other demographic, electrophysiological, or preoperative clinical characteristics are associated with pillar pain after CTR? Over a 35-month period, one surgeon performed 162 open carpal tunnel releases. Patients were eligible if they had sufficient cognitive and language function to provide informed consent and completed a self-reported questionnaire; they were not eligible if they had nerve entrapment other than CTR or if the surgery was covered by workers compensation insurance. Based on these criteria, 148 (91%) were approached for this study. Of those, 17 (9%) were lost to followup before 12 months, leaving 131 for analysis. Their mean age was 54 years (range, 32-78 years), and 81% (106 of 131) were women; 34% (45 of 131) had less than a high school education. We preoperatively measured pain sensitization by assessing the patients' pressure pain thresholds by stimulating pressure-induced pain in the pain-free volar forearm and administering a self-reported Pain Sensitivity Questionnaire minor subscale, an instrument that assesses pain intensity in daily life situations. We evaluated postoperative pillar pain using the "table test" (having the patient lean on a table with their weight on their hands placed on the table's edge with elbows straight) with an 11-point ordinal scale at 3, 6, and 12 months after their surgical procedures. We conducted bivariate and multivariable analyses to determine whether the patients' clinical, demographic, and pain sensitization factors were associated with their postoperative pillar pain severity after CTR. After controlling for relevant confounding variables such as age, education level, and functional states, we found that increased pillar pain severity was associated with the pressure pain threshold (β = -1.02 [-1.43 to -0.61], partial R = 11%, p = 0.021) and Pain Sensitivity Questionnaire minor (β = 1.22 [0.73-1.71], partial R = 17%, p = 0.013) at 3 months, but by 6 months, only Pain Sensitivity Questionnaire minor (β = 0.92 [0.63-1.21], partial R = 13%, p = 0.018) remained an associated variable for pillar pain. Additionally, gender (women) was associated with increased pain severity at 3 (β = 0.78 [0.52-1.04], partial R = 9%, p = 0.023) and 6 months (β = 0.72 [0.41-1.01], partial R = 8%, p = 0.027). At 3 months, pressure pain threshold, Pain Sensitivity Questionnaire minor, and gender (women) collectively accounted for 37% of the variance in pillar pain severity; at 6 months, Pain Sensitivity Questionnaire minor and gender (women) accounted for 21% of the variance, but no relationship between those factors and pillar pain was observed at 12 months. Gender (women) and preoperative pain sensitization measured by pressure pain threshold and self-reported Pain Sensitivity Questionnaire were associated with pillar pain severity up to 3 and 6 months after CTR, respectively. However, the influence of pain sensitization on pillar pain was diminished at 6 months and it did not show persistent effects beyond 12 months. Pain sensitization seems to be more important in the context of recovery from surgical intervention (in the presence of a pain condition) than in healthy states, and clinicians should understand the role of pain sensitization in the postoperative management of CTS. Future research may be needed to determine if therapeutic interventions to reduce sensitization will decrease the risk of pillar pain. Level III, prognostic study.

Use of SkinFibrometer® to measure skin elasticity and its correlation with Cutometer® and DUB® Skinscanner.

Skin elasticity is an important indicator of skin aging. The aim of this study was to demonstrate that the SkinFibrometer® is appropriate for measuring skin biomechanical properties, and to correlate it with elasticity parameters measured using the Cutometer® and with dermis structural properties measured using DUB® Skinscanner. Twenty-one individuals participated in this study. The skin of the cheek, around the eye, and the volar forearm were evaluated. To analyze correlations of elasticity parameters, the induration value against the indenter pressure of SkinFibrometer® and R, Q parameters of Cutometer® were compared. Dermal echogenicity using DUB® Skinscanner was compared with the induration value of SkinFibrometer® . The younger age group showed more firm and elastic skin properties compared to the older age group, and the elasticity values of the volar forearm were significantly higher than those of the cheek and around the eye region. Even though the measuring principle is different, both SkinFibrometer® and Cutometer® demonstrated the same trends of skin elasticity differences according to age and anatomical regions. There were significant correlations between the induration value of SkinFibrometer® , representing skin firmness, and R0, Q0 and R2, R5, R7, Q1, Q2 of Cutometer® , which represent skin firmness and resilience, respectively (P<.01). In addition, dermal echogenicity positively correlated with skin firmness determined by SkinFibrometer® (P<.01). We identified correlations between skin elasticity parameters evaluated by two different methods of suction and indentation, and demonstrated that the SkinFibrometer® is an objective, non-invasive evaluation tool for skin stiffness and elasticity.

Variation in skin hydration on the basis of Deha Prakriti (body constitution): A cross-sectional observational study

Background:Prakriti (body constitution) is an important concept of Ayurveda which is decided at the time of birth. It shows differences in physical, physiological and psychological characteristics of an individual. Variation in skin characteristics is found as per Prakriti.Aim:The aim of the present work was to study hydration of skin over volar forearm in people with different Prakriti with the help of skin diagnostic SD 27 instrument.Subjects and Methods:This was a cross-sectional study conducted at Cosmetic Technology Department in unmarried healthy female students of (18–30 years). A total of 904 volunteers were screened, of which 621 volunteers were further examined for Deha Prakriti for screening of single Dosha dominant Prakriti. 58 Vata, 70 Pitta and 61 Kapha dominant Prakriti were eligible for further study, but on actual day of skin examination, 50 volunteers in each group completed the study. Skin hydration was measured by skin diagnostic SD 27 instrument.Results:It was found that maximum people with Vata (92%) and Pitta dominant Prakriti (70%) had less hydration while (48%) Kapha dominant Prakriti volunteers had normal to dehydrated skin. Chi-square test was used for analysis. The Chi-square value is 45.9 and P = 0.0001, which is highly significant.Conclusion:The skin of Vata and Pitta dominant Prakriti had less hydration while hydration was well maintained in Kapha dominant Prakriti than that of Vata and Pitta Prakriti people.

Screening of BCG Vaccine Efficacy among Healthy Vaccinated Adults in Khartoum, Sudan

Tuberculosis (TB) is a major global health problem. The BCG is an attenuated vaccine. Tuberculin test is used as a nonspecific TB vaccination indicator. This study was aimed to determine the efficacy of BCG vaccine through screening of healthy, vaccinated adults’ subjects in Khartoum. A total of one hundred (n=100) healthy and TB symptoms free participants were screened by manteaux test. The participants were involving 55 (55%) males and 45 (45%) female. All participants were over 20 years and most of them had a scar in their vaccination site. All participants were screened through injection of purified protein derivative PPD (only 0.1 mL) intra-dermally into their volar forearm then 48-72 post-injection their induration diameter was measured. The results showed that out one hundred (n=100) participants, only 39 (39%) were positive for Manteaux test (≥ 10 mm diameter), while 61 (61%) were negative (≥ 10 mm diameter). Among the 39 positives, 33 show reading between 10 mm to 15 mm and 6 of them show zone ≥ 15 mm. In the other hand 53 out of 61 tuberculin test negative participants showed no induration post PPD injection and the rest were shows reading zone between 5 to 9 mm. The result shows that among the 39 positive participants 23 (58.97%) were male while only 16 (41.03%) were female. The mean of zone reading among the positive participants is higher in male 13.96 ± 3.29 than female 13.81 ± 2.22. The study concluded that more than half of the participants were negative for tuberculin test and this may be interpreted by either the vaccine was invalid or their cell-mediated immunity against TB is reduced. The discrepancy in the zone reading means between male and female may be related to some physiological difference. Further studies with more sample size and by using a more advanced technique (IFNγ) should be done to clarify the results.

A randomized, assessor-blinded, comparative study to evaluate the efficacy and safety of oat extract-based moisturizer in adult individuals with dry skin

Background: Dry skin or xeroderma is a very frequent condition which occurs at any age. Moisturizers including conventional oatmeal have been widely used to improve dry skin conditions. Oat-based moisturizer can protect, hydrate, and promote the endogenous barrier repair. Aim: This study aims to evaluate the efficacy and safety of oat extract-based moisturizer in adult individuals with dry skin. Materials and Methods: This study was a treatment-randomized, assessor-blinded, no treatment controlled, comparative study. A total of 36 individuals were included in the study. Oat extract-based moisturizer (test product) and control treatment (no product application) were randomized, as per randomization plan and applied to all individuals on the surface of volar forearm 2 cm (1 cm radius) in diameter. In addition, right cheek as control site and left cheek as test site (oat extract-based moisturizer lotion) were considered for sebum level and facial skin pH analysis. Results: Oat extract-based moisturizer possessed excellent skin moisturizing properties. Both the Corneometer® and modified Kligman score, respectively, showed significant improvement (P < 0.0001) in skin hydration and decrease in skin dryness with respect to baseline till 24 h postapplication. Furthermore, Cutometer® reading had statistically significant increase in skin elasticity as compared to baseline till 6 h postapplication. There was no statistically significant effect on skin pH and sebum level as compared to control treatment. This concludes that oat extract-based moisturizer is effective in improving skin hydration and elasticity without any change in skin pH and sebum levels. Conclusion: Test product (oat extract-based moisturizer lotion) was safe and well tolerated. Efficacy analysis showed that the effect of oat extract-based moisturizer was significant in terms of skin hydration and skin elasticity.

Age and Hydration dependence of jowl and forearm skin firmness in young and mature women.

Quantitative assessment of possible linkages between skin's firmness and water content is useful for cosmetic and clinical purposes and to better understand features of advancing age. Our goals were to characterize age-related differential features in skin firmness in women and determine the relationship between skin firmness and indices of skin water. Skin firmness was quantified using handheld devices that measure the force to indent skin 0.3 and 1.3 mm (F0.3 and F1.3). Skin hydration was quantified using handheld devices that measured tissue dielectric constant (TDC) at 300 MHz to skin depths of 0.5 and 2.0-2.5 mm. All parameters were measured bilaterally in the jowl area and volar forearm of 60 women grouped by age <45 years (YOUNG) and ≥45 years old (MATURE). All measured parameters were bilaterally symmetrical at jowl and forearm. Forearm and jowl indentation forces were greater in YOUNG with statistically significant declines with advancing age with regression relations most evident at shallower indentation depths (P < .001). Quantitative relations for arm and jowl were F0.3 = 0.256 × AGE + 32.7 mN and F0.3 = -0.07 × AGE + 17.7 mN. Firmness was related to TDC values only when indentation force and TDC were assessed on the arm at the shallowest skin depths, as weakly related to firmness and was observed to change with age only when measured to a depth of 0.5 mm represented by TDC5 = 0.096 × AGE + 32.7. Experimental finding show clear differences in skin firmness between age-groups with skin hydration playing a minor role. Possible explanations and suggestions for further studies are provided.

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics.

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.

DFD-01 Reduces Transepidermal Water Loss and Improves Skin Hydration and Flexibility.

IntroductionIn plaque psoriasis, the benefit of topical steroids is well established. The vehicle formulation of topical steroids may also provide benefit in addition to the effects of the steroid itself. DFD-01 (betamethasone dipropionate spray, 0.05%) is a formulation composed of a topical steroid in an emollient-like vehicle that enhances penetration to the target site of inflammation in the skin. The aim of this study was to assess the effect of DFD-01 and its vehicle on skin hydration and barrier function in compromised skin and to evaluate its effect on flexibility in healthy skin.MethodsEighteen healthy white volunteers were enrolled in each of two studies. In Study 1, dry shaving of volar forearms created a compromised skin barrier, through which transepidermal water loss (TEWL) was measured using an evaporimeter. Capacitance, a measure of epidermal hydration, was also measured at baseline and at 1, 2 and 4 h after application of DFD-01 or its vehicle formulation. In Study 2, intact skin flexibility was tested with a cutometer before and at 1, 2 and 4 h after application of DFD-01 or vehicle.ResultsIn Study 1, both DFD-01 and its vehicle were effective at reducing TEWL through the compromised stratum corneum. Capacitance measurements confirmed this finding; razor-chafed skin treated with either DFD-01 or vehicle exhibited levels of skin hydration similar to unshaved control skin. Study 2 found softening and greater flexibility of normal skin treated with either DFD-01 or vehicle compared with nontreated control skin samples.ConclusionsThese tests suggest that the DFD-01 formulation and its vehicle are each effective at retaining moisture within a damaged skin barrier and for softening and increasing the flexibility of intact skin.FundingDr. Reddy’s Laboratories.

Generalized Pain Sensitization and Endogenous Oxytocin in Individuals With Symptoms of Migraine: A Cross‐Sectional Study

The current study examined pain and neurogenic inflammation responses to topical capsaicin during the interictal period (between headache) and their relationship with plasma oxytocin in individuals with migraine. Individuals with migraine can experience generalized (extracephalic) hyperalgesia, which can persist even between headache attacks. Elevated levels of plasma and cerebrospinal fluid oxytocin have been observed during migraine attacks, oxytocin levels being positively associated with the intensity of migraine symptoms. However, whether oxytocin plays a role in the mechanisms of generalized pain sensitization and neurogenic inflammation during the interictal period has not been studied yet. Understanding migraineurs' interictal pain phenotype and endogenous oxytocin might help identify individuals who would benefit from intranasal oxytocin treatment. Thirty-two subjects with migraine and 26 healthy controls underwent pain testing. The current study compared capsaicin-induced pain, central sensitization (areas of secondary mechanical allodynia and hyperalgesia), and neurogenic inflammation (capsaicin-induced flare) responses on the nondominant volar forearm between migraineurs and healthy controls. Additionally, we studied plasma oxytocin levels and their relationship to migraine symptoms, experimental pain and affect. The results indicated a significant group effect (P = .019): Migraineurs reported greater capsaicin-induced pain unpleasantness (M = 1.2, SD = 1.4) on a 0-10 scale and showed larger areas of flare (LnM = 2.8, SD = 0.4) than healthy controls (M = 0.5, SD = 0.8; LnM = 2.6, SD = 0.4; ps < .032). In a subgroup analysis, enhanced capsaicin-induced pain unpleasantness was found in the chronic (P = .007), but not the episodic (Ps > .200), migraineurs. The oxytocin levels were elevated in migraineurs and accounted for 18% of the group difference in capsaicin-induced pain unpleasantness. Within migraineurs, interictal oxytocin levels were negatively associated with psychological distress (Ps < .030). However, during the interictal period, pain sensitivity in extracephalic regions and plasma oxytocin levels were unrelated to migraine symptom parameters (Ps > .074). Lastly, the results found no group difference in areas of secondary mechanical allodynia and hyperalgesia (Ps >.298). The current study revealed that individuals with migraine exhibit enhanced extracephalic capsaicin-induced pain unpleasantness and flare responses during interictal periods. In addition, migraineurs, especially those with chronic migraine, had slightly elevated interictal oxytocin levels compared to controls, which was associated with their affective component of experimental pain. Therefore, treatment targeting affective pain during the interictal period may help to reduce generalized pain in migraine. Furthermore, endogenous increases in oxytocin may be a compensatory mechanism that may help decrease affective distress in migraineurs. The therapeutic effects of intranasal oxytocin may benefit migraineurs by reducing their affective distress.

Between-day reliability of local thermal hyperemia in the forearm and index finger using single-point laser Doppler flowmetry.

To assess between-day reliability for LTH in glabrous and nonglabrous index finger skin and nonglabrous forearm skin, with single-point laser Doppler flowmetry. Part-1: In healthy, habitually active males (n=10), LTH was examined twice (~7-10days apart) for both skin types on the index finger. Part-2: Identical testing was performed on the volar forearm. Local heating (33-42°C at 1°C·20s-1 +20minutes at 44°C) was performed at all skin sites and baseline, initial peak, and plateau phases were identified. Data were expressed as raw CVC (laser-Doppler flux/MAP), and as CVC normalized to baseline (%CVC33°C ) and maximum heating (%CVC44°C ). Reliability was assessed using between-day mean difference, %CV, and ICC. Reliability (%CV) was poor at baseline for all forms of data presentation and for other phases with %CVC33°C . At the initial peak and plateau, reliability was moderate-poor (20%-26%) for CVC and good-moderate (6%-18%) for %CVC44°C . Reliability was good-moderate for vasodilatory onset time (10%-23%) and time to initial peak (6%-13%). For all sites, LTH reliability was acceptable for the timing, and for the initial peak and plateau using CVC or %CVC44°C .

Tempo-spatial discrimination is lower for noxious stimuli than for innocuous stimuli.

The exteroceptive sensory system is responsible for sensing external stimuli in relation to time and space. The aim of this study was to investigate the tempo-spatial properties of the exteroceptive system using painful laser heat and nonpainful mechanical touch stimulation. Thirteen healthy subjects were stimulated on the volar forearm using 2 paradigms: a continuous stimulation along a line on the skin and a 2-point stimulation. The line stimulations were delivered in both the distal and proximal direction with lengths of 25, 50, 75, and 100 mm. The 2-point stimulations were assessed by simultaneous stimuli at a point-to-point distance ranging from 10 to 100 mm, in steps of 10 mm. The subjects reported the intensity (0-10 numeric rating scale, 3: pain threshold) and either direction (line stimuli) or number of perceived points (2-point stimuli). All mechanical line stimulations were reported correctly, ie, a directional discrimination threshold of less than 25 mm. For painful laser line stimulation, the directional discrimination threshold was 68.5 and 70.2 mm for distally and proximally directed stimuli, respectively. The 2-point discrimination threshold for painful laser stimulation (67.9 mm) was higher than for the mechanical stimulation (34.5 mm). Numeric rating scale increased both with line length and distance between the 2 points (linear mixed model, P < 0.001). The findings indicate that the tempo-spatial acuity of the exteroceptive system is lower for noxious stimuli than for innocuous stimuli. This is possible due to the larger receptive fields of nociceptive neurons and/or less lateral inhibition.

In vivo THz imaging of human skin: Accounting for occlusion effects.

In vivo terahertz (THz) imaging of human skin needs to be done in reflection geometry due to the high attenuation of THz light by water in the skin. To aid the measurement procedure, there is typically an imaging window onto which the patient places the area of interest. The window enables better pulse alignment and helps keep the patient correctly positioned during the measurement. In this paper, we demonstrate how the occlusion caused by the skin contact with the imaging window during the measurement affects the THz response. By studying both rapid point measurements and imaging over an area of a human volar forearm, we find that even 5 seconds of occlusion affects the THz response. As the occlusion time increases, the skin surface water content increases, resulting in the reduction of the amplitude of the reflected THz pulse, especially in the first 3 minutes. Furthermore, it was found that the refractive index of the volar forearm increased by 10% to 15% after 20 minutes of occlusion. In this work, we examine and propose a model for the occlusion effects due to the quartz window with a view to compensating for its influence.

Impact of a pH 5 Oil-in-Water Emulsion on Skin Surface pH

Background: Human skin surface has a physiologically acidic pH (pH_ss). In cases of increased pH_ss, the acidity of the skin can be restored by topical formulations. We tested a pH 5 oil-in-water (O/W) emulsion for pH_ss regeneration and stabilization. Methods: We performed 2 experiments with 10 female study subjects in each. In both experiments, 2D imaging with luminescent sensor foils was used to determine pH_ss. Alkalization was reached by washing the volar forearm with a soap bar and warm running tap water for 20 min. Experiment 1: after defining the baseline pH_ss, we alkalized the respective area and measured pH_ss over a duration of 5 h, while applying emulsion every hour. Experiment 2: study subjects used the emulsion twice daily for 1 week. Then, pH_ss was measured before and after 5 min of washing a treated and an untreated area on the volar forearm. Results: (1) 5 h after alkalization, the treated arm showed a significantly lower pH_ss than the untreated one (5.87 ± 0.03 vs. 6.05 ± 0.03); (2) after washing, the treated area had a significantly lower pH_ss than controls (6.13 ± 0.03 vs. 6.27 ± 0.05). Conclusions: The tested pH 5 O/W emulsion seems to improve regeneration and stabilization of pH_ss.

Effects of stimulation technique, anatomical region, and time on human sweat lipid mediator profiles

Few studies compare sampling protocol effect on sweat composition. Here we evaluate the impact of sweat stimulation mode and site of collection on lipid mediator composition. Sweat from healthy males (n=7) was collected weekly for three weeks from the volar forearm following either pilocarpine iontophoresis or exercise, and from the forearm, back and thigh following pilocarpine iontophoresis only. Sweat content of over 150 lipid mediators were measured by liquid chromatography-tandem mass spectrometry. Seventy lipid mediators were routinely detected, including prostanoids, alcohols, diols, epoxides, ketones, nitrolipids, N-acylethanolamides, monoacylglycerols, and ceramides. Detected lipid mediators appeared unaffected by sampling site, though the forearm was the most consistent source of sweat. Pilocarpine-induced sweat showed increased concentrations of most detected compounds. Moreover, lipid mediator concentrations and profiles were temporally stable over the study duration. Sweat therefore appears to be a consistent and anatomically-stable source of lipid mediators, but care must be taken in comparing results obtained from different stimulation techniques.

Offset analgesia: The role of peripheral and central mechanisms.

Offset Analgesia (OA) can be evoked by a three-heat-stimulus train (T1-T2-T3), with T1 (5s) and T3 (20s) having the same temperature (e.g. 48°C) and T2 (5s) being slightly higher (1-3°C). OA is defined as a disproportional pain reduction caused by the slight temperature decrease from T2 to T3. As the pain modulatory mechanisms behind OA are still poorly understood, the current study aimed to investigate the role of peripheral and central mechanisms by applying heat stimuli to the same location and to different unilateral and bilateral locations. Young healthy volunteers participated in the study. A 'standard-OA' paradigm (48-49-48°C) was applied to the non-dominant volar forearm (T1-T2-T3 applied on the same location). 'Unilateral-OA' trials were applied on three different locations of the non-dominant volar forearm (the same dermatome). 'Bilateral-OA' trials were applied by shifting T1-T2-T3 between dominant and non-dominant volar forearms. A constant stimulus of 48°C was applied as control for the evoked pain. The pain intensities were continuously recorded using an electronic visual analogue scale. The largest pain intensity reduction was reported for the 'standard-OA' paradigm (p<0.001) compared with the control stimulus. Both 'Unilateral-OA' and 'Bilateral-OA' trials caused a significant pain reduction (p<0.05) compared with the control; however, the pain reduction was less than that evoked by 'standard-OA' (p<0.05). This study showed that OA could be elicited when the stimuli were applied both to the same and to different locations (ipsi- and contralateral) indicating that peripheral as well as central mechanisms are involved in mediating OA. This study investigated offset analgesia by applying thermal painful stimuli to the ipsi- and bilateral forearms in healthy subjects and found that both peripheral and central mechanisms seem to mediate offset analgesia.