Volar Forearm Research Articles

Can Offset Analgesia Magnitude Provide Additional Information About Endogenous Pain Modulation in People With Knee Osteoarthritis? An Experimental Study.

To investigate the relationship between offset analgesia magnitude and the responsiveness to conditioned pain modulation (CPM), temporal summation of (second) pain (TSP), and clinical pain severity in people with knee osteoarthritis (KOA). Electrical stimuli were applied to 88 participants with KOA to measure offset analgesia at the volar forearm of the dominant hand, and CPM and TSP at the most symptomatic knee and ipsilateral volar wrist. Clinical pain severity was assessed using the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOSPAIN). Linear mixed effects models evaluated pain modulatory effects across all tests, and Spearman's partial correlations assessed associations between offset analgesia, CPM, TSP, and KOOSPAIN while accounting for covariates of interest. Participants unable to validly finish all psychophysical tests were excluded from effect and correlation analyses but were evaluated for predictors of non-valid completion using bivariate Stochastic Search Variable Selection. Significant pain modulation was observed across all psychophysical tests (P < 0.05) and no meaningful predictors of non-valid test completion were found. Offset analgesia magnitude did not significantly correlate with CPM, TSP, or KOOSPAIN (p ≥ 0.05), with a maximum partial correlation coefficient of ρ = 0.21. Offset analgesia was not associated with CPM, TSP, or KOOSPAIN in people with KOA. Despite the lack of case-control studies comparing offset analgesia between people with KOA and healthy controls, these findings suggest that offset analgesia may provide information about endogenous pain modulation beyond CPM and TSP, though its clinical translation remains uncertain.

Effect of limb position change on capsaicin-evoked pain: Evidence of interplays between the vascular and nociceptive systems?

This experiment aimed at confirming our incidental observation that, when capsaicin is applied on the volar forearm, raising the arm to a vertical position leads to a dramatic increase in capsaicin-evoked pain and to explore possible underlying mechanisms. Twenty healthy volunteers received a 2% capsaicin patch on one forearm and a vehicle patch on the other. Patches were kept in place for 60 min. The perception caused by the patch was assessed repeatedly before, during and after patch application, both with the arm in horizontal resting position and raised vertically. In addition, capsaicin-induced secondary hyperalgesia was assessed using mechanical pinprick stimuli. Half of the participants were seated upright while the other half were lying supine, to assess whether the effect of limb position on capsaicin-evoked pain was due to gravity. After a few minutes of patch application, raising the capsaicin-treated arm (but not the vehicle-treated arm) led to a strong increase of the pain experienced at the patch. This effect of raising the arm did not differ between participants in the supine and seated groups and is therefore likely related to the position of the arm relative to the ground rather than to the body. Mechanical secondary hyperalgesia and the arm raising effect were strongly decorrelated at the last time point after patch removal, indicating different underlying mechanisms. Our results indicate that capsaicin-evoked pain can be strongly modulated by limb posture and that this effect may be caused by an interplay between vascular and nociceptive systems. Capsaicin-evoked pain can be strongly modulated by limb posture and this effect may be caused by an interplay between vascular and nociceptive systems.

Changes in Skin Barrier Function in Neonates: Daily Variation and Impact of Bathing.

The skin barrier function is an important predictor of neonatal barrier defects. This study aimed to investigate the daily changes in skin barrier function and the impact of bathing on skin barrier function in neonates. We assessed the transepidermal water loss (TEWL) and stratum corneum hydration (SCH) on the forehead, cheek, volar forearm, and chest from days 2 to 7 and at 1 month after birth. Additionally, we measured the values after bathing and compared them with the pre-bathing values. Sixty-six neonates were involved in the assessment, and each value at the four sites showed significant correlations. TEWL remained stable between days 2 and 7, but SCH significantly increased at most sites. Both significantly increased by 1.5-2 times in 1 month. After bathing, TEWL increased by more than 20% but decreased again after 3 h. TEWL did not change significantly with age during the first week of life. To minimize the effects of bathing, TEWL should be measured at least 3 h after bathing.

Decoding skin mysteries: Unveiling the link between microbiota and keloid scars through a Mendelian randomization study.

The cause of keloids remains unclear, but studies suggest a link between skin microbiota and keloid formation. However, the causal relationship has not been confirmed. This study utilized Genome-Wide Association Studies (GWAS) data from 2 population-based German cohorts, comprising a total of 1656 skin samples. To bolster the reliability of our results, we incorporated GWAS data from 3 keloid cohorts, encompassing 2555 patients and 870,556 controls (GWAS ID: keloid1, ebi-a-GCST90018874; keloid2, bbj-a-131; keloid3, ebi-a-GCST90018654). Subsequently, we employed bidirectional 2-sample Mendelian randomization (MR) analysis to probe the causal relationship between the variables. The primary method employed was the inverse-variance weighted (IVW) method, supported by heterogeneity analysis, horizontal pleiotropy testing, outlier detection, and "leave-one-out" sensitivity analysis. By synthesizing the results from 3 groups of MR analyses, we discovered a negative causal association between a.ASV063 [Finegoldia (unc.)] located on the volar forearm and keloid disease (IVW (keloid1) odds ratio (OR): 0.939, 95% confidence interval (CI): 0.886-0.994, P = .032; IVW (keloid2) OR: 0.897, 95% CI: 0.813-0.990, P = .031; IVW (keloid3) OR: 0.900, 95% CI: 0.825-0.981, P = .017). Similarly, a negative causal relationship may also exist between the genus: Bacteroides from the antecubital fossa and keloid disease (IVW (keloid1) OR: 0.928, 95% CI: 0.884-0.973, P = .002; IVW (keloid2) OR: 0.891, 95% CI: 0.820-0.968, P = .007; IVW (keloid3) OR: 0.918, 95% CI: 0.849-0.992, P = .030). Additionally, no reverse causation was found, with all analyses showing no signs of horizontal pleiotropy or heterogeneity. This study offers new insights for the prevention and treatment of keloids.

Endogenous pain modulation after sleep restriction in migraine: a blinded crossover study

BackgroundPatients with migraine are vulnerable to insufficient sleep, but the impact of sleep restriction is largely unknown. In addition, the importance of sleep may be different in patients with migraine who mostly have attack onsets during sleep, so called sleep-related migraine, compared to patients with non-sleep-related migraine. In this study we investigate the effect of sleep restriction on endogenous pain modulation in patients with migraine and healthy controls. We also compared the effect of sleep restriction in sleep-related and in non-sleep-related migraine.MethodsMeasurements were conducted in 39 patients with migraine between attacks and 31 controls, once after habitual sleep and once after two consecutive nights of partial sleep restriction. There were 29 and 10 patients with non-sleep-related and sleep-related migraine respectively. Test stimulus was 2-min tonic noxious heat to the left volar forearm. Temporal summation was calculated as the regression coefficient for rated pain in the late part of this 2-min stimulation. Conditioning stimulus was right hand-immersion in 7 °C water. Conditioned pain modulation was defined as the difference in rated pain with and without the conditioning stimulus and was calculated for temporal summation and mean rated pain for the test stimulus. The effect of sleep restriction on temporal summation and conditioned pain modulation was compared in migraine subjects and controls using two-level models with recordings nested in subjects.ResultsConditioned pain modulation for temporal summation of heat pain tended to be reduced after sleep restriction in patients with migraine compared to controls (p = 0.060) and, in an exploratory analysis, was reduced more after sleep restriction in sleep-related than in non-sleep-related migraine (p = 0.017). No other differences between groups after sleep restriction were found for temporal summation or conditioned pain modulation.ConclusionPatients with migraine may have a subtly altered endogenous pain modulation system. Sleep restriction may have an increased pronociceptive effect on this system, suggesting a mechanism for vulnerability to insufficient sleep in migraine. This effect seems to be larger in sleep-related migraine than in non-sleep-related migraine.

Changes in skin barrier over the first four days of life: a cross-sectional study.

We aimed to evaluate the trajectory of skin barrier properties in full-term newborns during the first four days after birth. Based on the MKNFOAD cohort (NCT02889081), transepidermal water loss (TEWL), stratum corneum hydration (SCH), skin pH, and sebum content at five anatomical sites (cheek, forehead, volar forearm, abdomen, and dorsal lower leg) were examined once within 96 h after birth in 384 full-term infants. Multivariable linear regression analysis was performed to assess variations in these skin barrier parameters with age adjusted for gestational age, neonate's sex, parents' allergy history, delivery mode, amniotic fluid characteristics, and birth weight. The regression coefficient (ß) and 95% confidence interval were reported. We analyzed a total of 384 neonates including 198 (51.6%) boys. TEWL values remained stable and showed no significant association with age (days). pH values exhibited a declining trend with age (p for trend <0.001). Both SCH values and sebum content grew with age (p for trend <0.001). During the first four days after birth, the skin TEWL remained stable, pH decreased, and the SCH and sebum content increased over time. These findings provide insights into the neonatal skin physiological development at the beginning of life. From birth to 96 h, TEWL was stable, pH showed a steep decline, SCH and sebum content increased. This study provides the first evidence of skin adaptation in the newborn due to changes in utero to after birth in the first 4 days of life in an Asian population. These findings will provide a new theoretical basis for neonatal skin physiology and clinical strategies for guiding newborn skin care.

Painful stimulation increases functional connectivity between supplementary motor area and thalamus in patients with small fibre neuropathy.

The lead symptom of small fibre neuropathy (SFN) is neuropathic pain. Recent functional magnetic resonance imaging (fMRI) studies have indicated central changes in SFN patients of different etiologies. However, less is known about brain functional connectivity during acute pain processing in idiopathic SFN. We conducted fMRI with thermal heat pain application (left volar forearm) in 32 idiopathic SFN patients and 31 healthy controls. We performed functional connectivity analyses with right supplementary motor area (SMA), left insula, and left caudate nucleus (CN) as seed regions, respectively. Since pathogenic gain-of-function variants in voltage gated sodium channels (Nav) have been linked to SFN pathophysiology, explorative connectivity analyses were performed in a homogenous subsample of patients carrying rare heterozygous missense variants. For right SMA, we found significantly higher connectivity with the right thalamus in SFN patients compared to controls. This connectivity correlated significantly with intraepidermal nerve fibre density, suggesting a link between peripheral and central pain processing. We found significantly reduced connections between right SMA and right middle frontal gyrus in patients with Nav variants. Likewise, connectivity between left CN and right frontal pole was decreased. Aberrant functional connectivity in SFN is in line with previous research on other chronic pain syndromes. Functional connectivity changes may be linked to SFN, highlighting the need to determine if they result from peripheral changes causing abnormal somatosensory processing. This understanding may be crucial for assessing their impact on painful symptoms and therapy response. We found increased functional connectivity between SMA and thalamus during painful stimulation in patients with idiopathic SFN. Connectivity correlated significantly with intraepidermal nerve fibre density, suggesting a link between peripheral and central pain processing. Our findings emphasize the importance of investigating functional connectivity changes as a potential feature of SFN.

Improvement effects of tapinarof on the skin barrier function in Japanese patients with atopic dermatitis

Background: Tapinarof is a nonsteroidal, topical, aryl hydrocarbon receptor agonist. Tapinarof has been shown to be efficacious and have acceptable safety profile in the treatment of atopic dermatitis (AD).Objective: We sought to evaluate the improvement effect of tapinarof on skin barrier function in patients with AD.Methods: This was an open-label, uncontrolled, single-center study. Japanese patients aged ≥20 years with AD (N = 30) were included in this study. Patients applied tapinarof cream 1% once daily to the target areas on the volar forearm for 8 weeks. The primary endpoints were changes from baseline in stratum corneum hydration (SCH) and transepidermal water loss (TEWL) at the target affected area at week 8.Results: The mean SCH value at the target affected area was 13.656 AU at baseline, 16.904 AU at week 4, and 16.423 AU at week 8. The SCH at the target affected area significantly increased from baseline to week 8, with a mean change of 2.826 AU (p = 0.0433). The mean TEWL value at the target affected area was 17.35 g/m2/hr at baseline, 10.01 g/m2/hr at week 4, and 9.52 g/m2/hr at week 8. The TEWL at the target affected area significantly decreased from baseline to week 8, with a mean change of −8.03 g/m2/hr (p &amp;lt; 0.0001). Clinical signs of AD at the target affected area were improved over time. No serious, severe, or treatment-related AEs were reported.Conclusion: Treatment with tapinarof led to an increase in SCH and a decrease in TEWL in patients with AD, indicating the potential improvement effect of tapinarof on skin barrier function.

Epidermal and dermal hydration in relation to skin color parameters.

Our goal was to investigate linkages between skin color parameters and skin hydration. Since most prior studies focused on stratum corneum hydration, we focused on epidermal and dermal hydration in relation to skin color parameters in both sexes. Thirty adults (16 female) with an age±SD of 24.3±0.6 years participated. Three sites on both volar forearms were evaluated for melanin index (MI), erythema index (EI), Individual Typology Angle (ITA), tissue dielectric constant (TDC) values to depths of 0.5mm (TDC0.5) and 2.5mm (TDC2.5), and Fitzpatrick skin type (FST). MI and EI were highly correlated (r=0.800, p<0.001) with maximum differences in MI and ITA along the arm of 3% and 6.3% with no difference between arms. Male MI was greater than females (p<0.01). Male TDC2.5 was 36.1±5.4 and correlated with EI (r=0.231, p=0.035). Contrastingly, female TDC25 was 28.5±3.6 with no correlation with EI but was correlated with MI (r=-0.301, p=0.003). These differential patterns held true for TDC0.5. For both sexes, FST and ITA were highly correlated (r=-0.756, p<0.001). The findings revealed several correlations between skin color parameters and hydration that differed between males in females in some cases. The observed correlations may indicate that melanin may differentially impact water-holding capacity between sexes and provides a future research target. Further, these initial findings also may hold significance for dermatological assessments and the customization of skincare treatments tailored to individual skin types and demographics.

Assessment of Intraday Variations in Skin Indentation Resistance.

Information about the mechanical properties of skin and their changes with age and other conditions is important to help characterize skin physiology and pathological changes. One method to obtain this information is to measure the force required to indent the skin to a specified indentation depth (FORCE). This process measures the tissue's resistance to indentation or its compressibility and is related to the tissue's elastic modulus. Since such measurements are made in clinical and other settings at various times of day (TOD), it is useful to estimate the extent of intraday variations in FORCE that may be expected. This report focuses on this issue. FORCE was self-measured on the volar forearm, 5 cm distal to the antecubital fossa, every two hours from 08:00 to 24:00 hours on two consecutive days by 12 medical students (six females and six males) who were trained in the measurement process using an indentation device (SkinFibroMeter). Variability in FORCE versus TOD was analyzed using the nonparametric Friedman test and differences between genders by the nonparametric Wilcoxon test. Differences between the first day (day 1) and the second day (day 2) were tested at each TOD. The whole-body fat percentage (FAT%) and water percentage (H2O%) were determined for each participant via bioimpedance measurements at 50 KHz. The age and BMI of the combined group (mean ± SD) were 24.5 ± 1.5 years and 23.2 ± 3.3 kg/m2.The overall average FORCE (mean ± SD) for the day over the 16 hours was 84.1 ± 22.7 mN and for day 2, it was 83.4 ± 28.5 mN with no significant difference between day 1 and day 2. For females, the overall two-day average FORCE (mean ± SD) over the 16 hours was 81.8 ± 20.3 mN and for males, it was 85.7 ± 30.1 mN with no significant difference between them (p = 0.271). Overall, there was no statistically significant difference in FORCE among TOD (p = 0.568). FORCE was not correlated with either FAT%, HTO%, or BMI. The findings indicate no statistically significant variation in indentation force in females, males, or combined concerning the TODof the measurement or differences between consecutive days at corresponding times. This suggests that whether such measurements are done in a research setting or within a clinic, they can be done at various TODwith minimal expected variation for a given subject. However, an extension of these findings to persons with skin conditions or ages not herein evaluated must await further study.

Intra-day variations in volar forearm skin hydration.

Skin hydration (SKH) measurements are used for multiple purposes: to study skin physiology, to clinically investigate dermatological issues, and to assess localized skin water in pathologies like diabetes and lymphedema. Often the volar forearm is measured at various times of day (TOD). This report aims to characterize intra-day variations in volar forearm SKH to provide guidance on expected TOD dependence. Forty medical students (20 male) self-measured tissue dielectric constant (TDC) on their non-dominant forearm in triplicate as an index of local skin tissue water every 2 h starting at 0800 and ending at 2400h. All were trained and pre-certified in the procedure and had whole-body fat (FAT%) and water (H2O%) measured. Day average TDC (TDCAVG) was determined as the average of all time points expressed as mean±SD. Males versus females had similar ages (25.1±2.2 yearsvs. 25.1±1.5 years), higher H2O% (56.6±5.0vs. 51.8±5.7, p=0.002), and higher TDCAVG (32.7±4.1vs. 28.5±5.1, p=0.008). TDC values were not significantly impacted by H2O% or FAT%. Female TDC exhibited a significant decreasing trend from morning to night (p=0.004); male TDC showed no trend. Skin water assessed by TDC shows some intra-day variations for females and males but with quite different temporal patterns. Clinical relevance relates to the confidence level associated with skin hydration estimates when measured at different times of day during normal clinic hours which, based on the present data, is expected to be around 5% for both males and females.

Characteristics of the Gantzer muscle and implications for its use as a tendon-graft source in upper extremity reconstruction

BackgroundThe Gantzer muscle is an anatomical variant muscle that functions in flexion of the volar forearm. The prevalence and laterality of this muscle has been studied more recently in the literature. This study aimed to determine the prevalence and size of this muscle and tendon. MethodsThis was an observational study done from September 2021 to January 2022 at the University of North Texas Health Science Center in Fort Worth, Texas. Cadaveric dissection was conducted in the Department of Physiology and Anatomy. 50 pairs for a total of 100 forearms were dissected bilaterally in cadavers comprising 17 females (34 %) and 33 males (66 %) to identify the Gantzer muscle. The mean age at death was 68.8 years of age (range 40–91 years). When present, the dimensions of each Gantzer tendon were measured in millimeters using digital calipers. As a study of cadaveric specimens, this study was exempt from Institutional Review Board (IRB) approval. ResultsThe Gantzer muscle was present in 62 of the 100 forearms (62 %). All 62 Gantzer muscles originated from flexor digitorum superficialis (FDS) (100 %). Of the 62 Gantzer muscles, 42 inserted distally into flexor pollicus longus (FPL) (72.5 %), while the remaining 17 muscles inserted distally into flexor digitorum profundus (FDP) (27.5 %). The tendons inserting into FDP had an average length of 65.495 mm, while those inserting into FPL had an average length of 16.353 mm (p = 0.002). The Gantzer muscle was present in 24 of the 33 male specimens (72.7 %) and 13 of the 17 female specimens (76.4 %). Of the 62 Gantzer muscles, 50 were present bilaterally (80.6 %), and there was no significant difference in bilateral occurrence between sexes (p = 0.189). ConclusionsOur results suggest that the Gantzer muscle may be of sufficient size and present commonly enough in the general population to be considered as an alternative graft source for certain upper extremity reconstruction procedures in place of, or in addition to, palmaris longus, extensor toe tendons, and other commonly used tendon grafts. In this study, when palmaris longus was absent in a specimen, a Gantzer muscle was likely present, and may provide surgeons an alternative tendon graft source in the upper extremity without requiring additional incisions in the lower extremity for alternative tendon graft sources. Further biomechanical testing of the Gantzer tendon with comparisons to other common tendon graft sources is warranted.

Is Tourniquet Pain the Result of Increased Compartment Pressure in the Forearm?

The pneumatic tourniquet has been a mainstay in upper extremity surgery by allowing the surgeon to operate in a blood-free field. Many upper extremity surgical procedures are done under local anesthesia or minimal sedation, and the problem of tourniquet pain is a vexing one. The question is posed: Is tourniquet pain the result of increased compartment pressure in the forearm? This study measured compartment pressures of the volar forearm in 10 healthy normotensive volunteers before inflation of a pneumatic tourniquet and compared it with pressure measurements taken while the tourniquet was still inflated after 15 minutes. Compartment pressures were measured using a Stryker needle manometer; all measurements were taken in the volar forearm by the senior author (C.H.M.). There was no increase in the volar/flexor compartment pressure of the forearm after 15 minutes of tourniquet inflation. All subjects complained of pain of the forearm, characteristically what is commonly called "tourniquet pain." We therefore conclude that in the upper extremity, at least for relatively short operating times, appropriate inflation of a tourniquet does not induce the early onset of increased compartment pressure in the forearm.

Symptomatic treatment of mosquito bites with a thermo-therapeutic medical device: a prospective, intraindividual compared, placebo-controlled, randomized clinical trial

Objective: Agonizing itching (pruritus), heat, and burning are common symptoms of mosquito bites. In this study, we present a thermo-therapeutic medical device for the symptomatic treatment of mosquito bites. Current research suggests the potential of a thermal (heat) stimulus for pruriceptor counter-stimulation and reduced histamine-signaling to relieve the symptoms of mosquito bites. The purpose of this clinical investigation was to investigate the efficacy and safety of the thermo-therapeutic medical device (class II) in the symptomatic treatment of mosquito bites in an intraindividual comparison to a placebo device (PD) examined under standardized conditions. This was achieved by assessing pruritus and wheal size over time after induction of a mosquito bite on the volar forearm. Methods: The itching was rated on a Visual Analog Scale ranging from 0 mm (no itching) to 100 mm (worst imaginable itching). The wheal size was measured in approximation to the area of an eclipse before and ~30 minutes after the treatment with the investigational device. Local tolerability was assessed by the investigator according to a score ranging from 0 (no irritation) to 4 (very strong irritation) and the subjects stated if the itching sensation was completely gone after treatment (yes/no question). Results: The mean area under the curve of the difference to baseline for the treatment with the medical device was statistically significantly bigger than for the treatment with the PD (1311.71 vs 914.61, respectively; P = 0.0127). Conclusions: Treatment of a mosquito bite with a thermo-therapeutic medical device significantly reduced pruritus and led to a faster reduction of the itching sensation as compared with PD. A significant itch reduction started immediately (1 min) after treatment with the medical device (post hoc analysis). The treatment with the medical device was well tolerated by all subjects and no adverse events related to the medical device occurred.

Skin lightening properties of zerumbone cream: A placebo-controlled study.

Despite the demonstrated anti-melanogenic and UV protective effects of Zerumbone (ZER) invitro, there is a lack of clinical trials that have been done to assess these properties. The primary objective of this study was to assess the effectiveness of ZER in lightening the skin tone of human participants with a single-blind approach. Twenty-six participants were randomly assigned to two groups to investigate the application location (left or right volar forearm) for the placebo and ZER creams. Both creams were topically administered to the volar forearms twice daily over a duration of 4 weeks. Initial skin irritation was assessed before and 30 min after applying creams. The melanin and erythema levels were quantified with Mexameter MX 18. Twenty participants were included in the analysis. The cream formulation had excellent physical properties and was well-received by the participants. The initial skin irritation study results indicated that neither of the creams elicited an allergic reaction. The administration of ZER cream resulted in a statistically significant reduction in melanin levels (p < 0.05) after 1 week compared to the initial baseline. Furthermore, after 2 weeks of application, ZER cream demonstrated significant differences in melanin levels compared to placebo (p < 0.05). No adverse effects were observed in the group using ZER cream. ZER demonstrated significant potential as a skin-lightening agent.

Associations between sun exposure, skin pH, and epidermal permeability in pregnancy: A longitudinal observational study.

Little is known about how sun exposure may affect the maternal skin barrier during pregnancy when many hormonal and physiological changes occur. In this longitudinal observational study, 50 pregnant women were recruited at 18-24 weeks' gestation, 25 in summer-autumn, and 25 in winter-spring. At three time points in pregnancy at 18-24, 28-30, and 36-38 weeks' gestation, participants completed a validated sun exposure questionnaire and had skin permeability and surface pH measured on the volar forearm. We identified an association between increased sun exposure and increased skin permeability at 18-24 weeks' gestation (β = 0.85, p = 0.01). Lower transepidermal water loss (decreased skin permeability), mean = 12.1 (SD = 5.1) at 28-30 weeks' gestation was observed, compared to mean = 12.6 (SD = 4.0) at 18-24 weeks' and mean = 13.7 (SD = 8.5) at 36-38 weeks' gestation (n = 27, β = -1.83, p = 0.007). Higher skin pH readings, mean = 5.80 (SD = 0.58) were found at 28-30 weeks' gestation, compared to mean = 5.25 (SD = 0.62) at 18-24 weeks' and mean = 5.47 (SD = 0.57) at 36-38 weeks' gestation (n = 27, β = 0.40, p = 0.004). These gestational fluctuations remained after adjusting for Fitzpatrick skin type, season, and sun exposure. We observed gestational fluctuations in both skin permeability and skin pH, with 28-30 weeks' gestation being a significant point of difference compared to mid- and late-pregnancy periods.

Motion-resistant three-wavelength spatial frequency domain imaging system with ambient light suppression using an 8-tap CMOS image sensor.

We present a motion-resistant three-wavelength spatial frequency domain imaging (SFDI) system with ambient light suppression using an 8-tap complementary metal-oxide semiconductor (CMOS) image sensor (CIS) developed at Shizuoka University. The system addresses limitations in conventional SFDI systems, enabling reliable measurements in challenging imaging scenarios that are closer to real-world conditions. Our study demonstrates a three-wavelength SFDI system based on an 8-tap CIS. We demonstrate and evaluate the system's capability of mitigating motion artifacts and ambient light bias through tissue phantom reflectance experiments and in vivo volar forearm experiments. We incorporated the Hilbert transform to reduce the required number of projected patterns per wavelength from three to two per spatial frequency. The 8-tap image sensor has eight charge storage diodes per pixel; therefore, simultaneous image acquisition of eight images based on multi-exposure is possible. Taking advantage of this feature, the sensor simultaneously acquires images for planar illumination, sinusoidal pattern projection at three wavelengths, and ambient light. The ambient light bias is eliminated by subtracting the ambient light image from the others. Motion artifacts are suppressed by reducing the exposure and projection time for each pattern while maintaining sufficient signal levels by repeating the exposure. The system is compared to a conventional SFDI system in tissue phantom experiments and then in vivo measurements of human volar forearms. The 8-tap image sensor-based SFDI system achieved an acquisition rate of 9.4 frame sets per second, with three repeated exposures during each accumulation period. The diffuse reflectance maps of three different tissue phantoms using the conventional SFDI system and the 8-tap image sensor-based SFDI system showed good agreement except for high scattering phantoms. For the in vivo volar forearm measurements, our system successfully measured total hemoglobin concentration, tissue oxygen saturation, and reduced scattering coefficient maps of the subject during motion (16.5cm/s) and under ambient light (28.9lx), exhibiting fewer motion artifacts compared with the conventional SFDI. We demonstrated the potential for motion-resistant three-wavelength SFDI system with ambient light suppression using an 8-tap CIS.

Skin Barrier Function Assessment: Electrical Impedance Spectroscopy Is Less Influenced by Daily Routine Activities Than Transepidermal Water Loss.

Skin barrier function assessment is commonly done by measuring transepidermal water loss (TEWL). An important limitation of this method is the influence of intrinsic and extrinsic factors. Electrical impedance spectroscopy (EIS) is a lesser-established method for skin barrier function assessment. Some influential factors have been described, but no guidelines exist regarding the standardization of these measurements. To evaluate the effect size of daily routine activities on TEWL and EIS, as well as their correlation with age and anatomical differences. Healthy participants (n=31) were stratified into three age groups (18-29, 30-49, and ≥50 years). In a climate-controlled room, EIS and TEWL measurements were performed on the left and right volar forearm and abdomen. Body cream application decreased TEWL and EIS values after 15 and 90 minutes. Skin washing decreased TEWL for 15 minutes and EIS values for at least 90 minutes. TEWL was increased 5 minutes after moderate to intense exercise. Coffee intake increased TEWL on the abdomen after 60 minutes. TEWL and EIS values did not correlate with participants' age and no anatomical differences were observed. No correlation was observed between TEWL and EIS. Body cream application and skin washing should be avoided at least 90 minutes prior to measurements of TEWL and EIS. Exercise and coffee intake should also be avoided prior to TEWL measurements. EIS may be a promising tool for skin barrier function assessment as it is less affected by daily routine activities than TEWL.

Realism of Tactile Texture Playback: A Combination of Stretch and Vibration.

This study investigates the effects of two stimulation modalities (stretch and vibration) on natural touch sensation on the volar forearm. The skin-textile interaction was implemented by scanning three textures across the left forearm. The resulting skin displacements were recorded by the digital image correlation technique to capture the information imparted by the textures. The texture recordings were used to create three playback modes (stretch, vibration, and both), which were reproduced on the right forearm. Two psychophysical experiments compared the texture scans to rendered texture playbacks. The first experiment used a matching task and found that to maximize perceptual realism, i.e., similarity to a physical reference, subjects preferred the rendered texture to have a playback intensity of 1X - 2X higher on DC components (stretch), and 1X - 3.5X higher on AC components (vibration), varying across textures. The second experiment elicited similarity ratings between the texture scans and playbacks and showed that a combination of stretch and vibration was required to create differentiated texture sensations. However, the intensity amplification and use of two stimuli were still insufficient to create fully realistic texture sensations. We conclude that mechanisms beyond single-site uniaxial stimuli are needed to reproduce realistic textural sensations.

Phase 1, randomized, rater and participant blinded placebo-controlled study of the safety, reactogenicity, tolerability and immunogenicity of H1N1 influenza vaccine delivered by VX-103 (a MIMIX microneedle patch [MAP] system) in healthy adults.

The MIMIX platform is a novel microneedle array patch (MAP) characterized by slowly dissolving microneedle tips that deploy into the dermis following patch application. We describe safety, reactogenicity, tolerability and immunogenicity for MIMIX MAP vaccination against influenza. The trial was a Phase 1, exploratory, first-in-human, parallel randomized, rater, participant, study analyst-blinded, placebo-controlled study in Canada. Forty-five healthy participants (18 to 39 years of age, inclusive) were randomized in a 1:1:1 ratio to receive either 15 μg or 7.5 μg of an H1N1 influenza vaccine, or placebo delivered via MIMIX MAP to the volar forearm. A statistician used a computer program to create a randomization scheme with a block size of 3. Post-treatment follow-up was approximately 180 days. Primary safety outcomes included the incidence of study product related serious adverse events and unsolicited events within 180 days, solicited application site and systemic reactogenicity through 7 days after administration and solicited application site erythema and/or pigmentation 14, 28, 56 and 180 days after administration. Immunogenicity outcomes included antibody titers and percentage of seroconversion (SCR) and seroprotection (SPR) rates determined by the hemagglutination inhibition (HAI) assay. Exploratory outcomes included virus microneutralization (MN) titers, durability and breadth of the immune response. The trial was registered with ClinicalTrials.gov, number NCT06125717. Between July 7, 2022 and March 13, 2023 45 participants were randomized to a treatment group. One participant was lost to follow up in the 15 μg group and 1 participant withdrew from the 7.5 μg dose group. Safety analyses included n = 15 per group, immunogenicity analyses included n = 14 for the 15 μg and 7.5 μg treatment groups and n = 15 for the placebo group. No SAEs were reported in any of the treatment groups. All treatment groups reported solicited local events within 7 days after vaccination, with mild (Grade 1) erythema being the most frequent symptom reported. Other local symptoms reported included mostly mild (Grade 1) induration/swelling, itching, pigmentation, skin flaking, and tenderness. Within 7 days after vaccination, 2 participants (4.4%) reported moderate (Grade 2) erythema, 1 participant (2.2%) reported moderate (Grade 2) induration/swelling, and 1 participant (2.2%) reported moderate (Grade 2) itching. There was an overall reduction in erythema and pigmentation reported on Days 15, 29, 57, and 180 among all treatment groups. Systemic symptoms reported within 7 days after vaccination, included mild (Grade 1) fatigue reported among all treatment groups, and mild (Grade 1) headache reported by 1 participant in the 7.5 μg treatment group. No study drug related severe symptoms were reported in the study. Group mean fold rises in HAI titers ranged between 8.7 and 12-fold, SCRs were >76% and SPRs were >92% for both VX-103 dose groups thereby fulfilling serological criteria established by the EMA and FDA for seasonal influenza vaccines. Longitudinal assessments demonstrate persistence of the immune response through at least Day 180. The MIMIX MAP platform is safe, well tolerated and elicits robust antibody responses.