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Introduction Systemic cryotherapy is a popular treatment involving a short stay in a cryogenic chamber at a temperature below −100 °C. This leads to a number of physiological reactions, some of them also observed in the skin. The aim of the study was to analyze the effect of a single cryogenic treatment on selected skin characteristics (skin pH, level of hydration and TEWL – Transepidermal Water Loss) in young, healthy people. Materials and methods Skin characteristics in 77 young people (23.63 ± 1.36 years) were assessed. In the study, 43 women and 33 men who took part in a one-time treatment (−120 °C) lasting 3 min. Measurements were made on the forearm skin and (in men) on the face twice: before and immediately after the procedure. Results: Initial differences in hydration of the stratum corneum and TEWL were observed between the group of women and men. After one treatment, the examined characteristics of the forearm skin did not change, and an unfavorable increase in TEWL in men was indicated in the facial area. Conclusions A single stay in the cryogenic chamber, while maintaining the correct methodology of the treatment, is safe for the skin. The changes taking place depend on the body surface area tested, which indicates that the skin on the limbs and on the face reacts differently to the cryogenic stimulus.

Summary Purpose After harvesting a radial forearm flap (RFF) an optimal aesthetic and functional restitution of the donor site is required. In order to cover the secondary defect of the donor site, several solutions are currently available, but there is still no real evidence of the most reliable option. A retrospective study was conducted in order to evaluate a new technique of forearm coverage with artificial dermis: the association of full thickness skin graft (FTSG) with Matriderm®. Methods Our study included all RFF performed during a 34-month period. Forty-three forearm secondary defects after harvesting a RFF (16 men, 27 female) were included. Forearm donor site was covered using three techniques: a simple FTSG, split thickness skin graft (STSG) with Matriderm® or FTSG with Matriderm®. Clinical evaluations based on residual functionality, skin quality and aesthetic result were assessed using respectively the Disabilities of the Arm, Shoulder and Hand (DASH) score, the Vancouver Scar Scale (VSS) score and a blind panel questionnaire. Results FTSG with Matriderm® showed an improved DASH (10.6/100) and VSS score (5.5/13) if compared to the other techniques, mean surgeon satisfaction score was 3/5, mean patient satisfaction score was 3/5 in the FTSG with Matriderm® group. Conclusion The results of this study revealed that the new association of FTSG with Matriderm® improves the DASH score and the aesthetic outcomes resulting to be a reliable solution in treating full thickness forearm skin defects after RFF harvesting.

Several studies have shown that advanced glycation end products (AGE) play a role in both the microvascular and macrovascular complications of diabetes and are closely linked to inflammation and atherosclerosis. AGEs accumulate in skin and can be detected using their auto fluorescence (AF).A significant correlation exists between AGE AF and the levels of AGEs as obtained from skin biopsies. A commercial device, the AGE Reader, has become available to assess skin AF for clinical purposes but, while displaying promising results, it is limited to single-point measurements performed in contact to skin tissue. Furthermore, in vivo imaging of AGE accumulation is virtually unexplored.We proposed a non-invasive, contact-less novel technique for quantifying fluorescent AGE deposits in skin tissue using a multispectral imaging camera setup (MSI) during ultraviolet (UV) exposure. Imaging involved applying a region-of-interest mask, avoiding specular reflections and a simple calibration. Results of a study conducted on 16 subjects with skin types ranging from fair to deeply pigmented skin, showed that AGE measured with MSI in forearm skin was significantly correlated with the AGE reference method (AGE Reader on forearm skin, R=0.68, p=0.005). AGE measured in facial skin was borderline significantly related to AGE Reader on forearm skin (R=0.47, p=0.078). These results support the use of the technique in devices for non-touch measurement of AGE content in either facial or forearm skin tissue over time. SEMEOTICONS

Moisturizing creams and lotions are commonly used in daily life for beauty and treatment of different skin conditions such as dryness and wrinkling, and ultrasound stimulation has been used to enhance the delivery of ingredients into skin. However, there is a lack of convenient methods to study the effect of ultrasound stimulation on lotion absorption by skin in vivo. Ultrasound biomicroscopy was adopted as a viable tool in this study to investigate the effectiveness of ultrasound stimulation on the enhancement of lotion delivery into skin. The forearm skin of 10 male and 10 female young subjects was tested at three different sites, including two lotion treatment sites with (Ultrasound Equipment - UE ON) and without (UE OFF) ultrasound stimulation and a control site without any lotion treatment. 1 MHz ultrasound with a duty cycle of 1.7%, a spatial peak temporal peak pressure of 195 kPa and an average power of 0.43 W was used for the stimulation. The skin thickness before, immediately after (0 min), and 15 and 30 min after the treatment was measured by an ultrasound biomicroscopic system (55 MHz). It was found that the skin thickness significantly increased immediately after the lotion treatment for both UE ON (from 1.379 ± 0.187 mm to 1.466 ± 0.182 mm, p

Half-mask respirators have been increasingly used in public facilities to protect against indoor air contaminants. However, when they are used, the respiratory heat flow is restrained and its release into the environment is limited. This study evaluated the thermal burden on respirator users in an indoor environment where a significant heat load from hot-and-humid air is introduced. Twenty-five participants walked on the stairs at a speed of 4.6 km/h wearing a filtering facepiece respirator (N95 mask) or elastomeric facepiece respirator under varying air temperatures and relative humidity (RH). The thermo-physiological properties on the nasal, facial, and forearm skin and the temperature/RH of the breath were evaluated. Thermal sensation was also surveyed. The results showed that a thermal microclimate was developed inside the mask, with the heat index in the microclimate of N95 masks being elevated to 61.2–67.9 °C and a risk level of “Extreme Danger”. The metabolic heat from respirator use shifted the paradigm of thermoregulation to a scheme involving localized enhancement in thermoregulation. When using N95 masks the skin moisture level was increased by 77%–588% and the transepidermal water loss by 18%–72%. Thermoregulation underlying heat strain was near-saturated at 33 °C, and an abrupt increase of 1.6- to 3.6-fold in thermal sensation was concurrently observed. The threshold-controlled increase in sensation was likely a result of the thermal strain capacity being overwhelmed. These findings demonstrated that even under room temperature, caution should be exercised when using N95 masks for performing tasks of moderate metabolic load.

The aim of this study was to investigate physiological interactions between fabric and the human body via skin and the resultant disturbance to blood flow, which in turn influences the skin temperature and the sensation of warmth and chilliness, thus the feeling of comfort. We focussed on the effects on the forearm skin blood flow by different local physical stimuli from fabrics. The blood flows were examined under three protocols: (1) using fabrics of different fiber types and fiber blending, (2) different surface characteristics of the same fabric and fiber type, and (3) different moisture levels of the same fabric type. A total of five different fabrics were wrapped over the forearm of a female subject at a good health state for test. The fabric samples were preconditioned for 24 h, and the subject sat for 30 min, in both cold and dry ambient conditions (20.5±0.5 °C, 45±5 p.100 RH) to reach equilibrium before testing. The forearm skin blood flow and temperature were recorded by a laser-Doppler flowmeter (DP1T/7-V2) with two probes mounted on both forearms to eliminate any systematic common mode fluctuations. Several conclusions were drawn from our test data. First, the fabric impact on both skin temperature and blood flow can be significant. Also fabric surface characteristics play important role, especially during the transient heat exchange at the beginning of contact. Finally, moisture level in the samples exhibits considerable influences on skin temperature and blood flow, and the higher the moisture level, the longer the duration of the impact.

PURPOSE: Longitudinal scars on the radial quadrant of the distal forearm skin envelope are typically observed to be wider than those on the ulnar quadrant and have an increased incidence of hypertrophic change. Forearm rotation movements may produce differential skin tensions within the forearm skin envelope, and this may lead to differential scarring patterns. This study was designed to measure skin tension changes in the forearm as a result of rotational position to see if these would be consistent with the hypothesis that greater tension changes are observed on the radial aspect of the forearm. METHODS: The effect of forearm position on the magnitude and direction of skin tension was measured on human volunteers. Standardized circles were marked in circumferential fashion at specified intervals on forearm skin, and the angular and dimensional distortion of these circles that occurred with forearm rotation was measured with caliper and goniometer. Data were analyzed for statistical significance using paired t-test. RESULTS: Pronation and supination resulted in marked angular rotation of the lines of maximal skin tension at all sites on the forearm. Supination resulted in a greater angular deviation of the lines of maximal skin tension from the longitudinal line of usual surgical incision, particularly on the radial aspect of the forearm. In supination, the magnitude of ellipsoid deformation at the distal forearm was greater on the radial aspect compared with that of the ulnar. Similar significant changes were also demonstrated at the mid-forearm and proximal forearm levels. CONCLUSIONS: This study systematically maps the effects of pronation and supination on skin tension within the forearm skin envelope. The significant changes occurring in both the ellipsoid deformation and ellipsoid orientation support our hypothesis that the magnitude of skin tension changes significantly with forearm rotation. The radial aspect of the distal forearm experiences the greatest changes, particularly as the forearm supinates.

are common complications of the procedure. This study presents 9 cases of unusual complications of shoulder arthroscopy: 8 from the senior authors (M.G.H. and A.D.S.), whose experience includes more than 4000 shoulder arthroscopies, and 1 referral from another institution. Some of these complications are difficult to attribute to the surgical procedure. They are, however, undesirable sequelae, and we believe that they should be reported. Our standard practice in all cases of shoulder arthroscopy, unless there are specific contraindications, is to administer a general anesthetic and, frequently, an interscalene block. We perform shoulder arthroscopy with the patient in the lateral decubitus position, supported by a deflated bean bag. The arm is suspended by means of a 4-kg weight through use of single overhead traction applied through nonadhesive forearm skin traction. Our irrigation fluid is water in 1000-mL bags, 0.5 mL of 1:1000 adrenalin being added to each bag. We use a hand pump to assist in distension when it is required. Our 3 standard portals are the posterior, anterior, and lateral portals. We routinely perform electrosurgery with a diathermy unit (Valleylab Inc, Boulder, Colo). There was no deviation from our standard practice in any of the cases described in this article, except as specifically noted in the individual case histories.

A atomic absorption spectrometry method for the determination of nickel in finger nails and in the upper layer of the skin (stratum corneum) was developed, validated and applied in an experimental study on nickel allergic patients and non-nickel allergic controls. The relative intermediate precision (including between-day variation) was in the range 5.5–12%, and the limit of detection was 0.2 μg nickel per g nail and 1 ng nickel per skin sample, respectively. The baseline levels of nickel in nails were approximately 1.58 μg per g nail, which is comparable to previously reported reference values. No differences could be observed between patients and controls. Both nickel in nails and in skin samples increased significantly when low nickel doses were applied to fingers and the forearm, respectively. This suggests that nickel in nails and in skin samples may be relevant in characterizing occupational skin exposure to nickel.

Skin viscoelasticity was evaluated by a fast, noninvasive assay based on the measurement of the speed of elastic shear wave propagation in the skin by a new portable and user-friendly viscoelasticity skin analyzer. The range of speed of elastic shear wave propagation measured by viscoelasticity skin analyzer allows the evaluation of the stiffness of a wide spectrum of artificial materials as well as the viscoelasticity of skin of laboratory animals and human subjects. The directional nature of the measurement enables to monitor the anisotropy of the materials tested. The speed of elastic shear wave propagation was shown to have a positive correlation with the stiffness of the material tested. In symmetric contralateral areas of intact skin in rabbit ears, similar viscoelasticity and anisotropy were observed. Twenty-four hours after the induction of local edema by croton oil, skin stiffness and anisotropy were significantly increased. In healthy human subjects of both sexes significant variations in skin stiffness and anisotropy were observed in three different skin areas along the forearms, but the speed of elastic shear wave propagation was similar in the symmetric contralateral areas. Age (17–65 y) seemed to have a limited effect on the viscoelasticity of the forearm skin. Hydrating creams decreased the stiffness of the forearm skin for only ≈ 3 h. The stiffness and anisotropy of the skin of the breasts in female volunteers (20–86 y) increased with age, but the speed of elastic shear wave propagation was similar in symmetric contralateral areas in the same individuals. Based on these results, we propose the application of the viscoelasticity skin analyzer in experimental and clinical practice for quantitative evaluation of skin condition.

Objective: To measure the ability of a multiple-barrier product to inhibit the passage of a highly water-soluble tracer into the skin when compared with products currently available on the market (Peri-Care; Sween Corp., and Double-Guard; C. R. Bard, Inc.) Design: Dye extraction from the skin was measured at specified intervals and a spectrophotometric measurement of the amount of dye was obtained. Setting and Subjects: Two groups of light-skinned volunteers, 6 young adults subjects, aged 22 to 31 years, and 6 older subjects, aged 61 to 73 years, were studied in a controlled laboratory setting. Instruments: Spectronic 601 spectrophotometer. Methods: Rectangles (1 inch × 4 inch), inscribed on the ventral forearm skin, were divided into 4 1 inch × 1-inch squares, onto which 50 μL of different barrier products were spread. Band-Aids (Johnson & Johnson), saturated with 70 μL of an FD&C red dye No. 40 solution, were placed over the treated squares and left in place for specified intervals up to 8 hours. Similarly treated Band-Aids placed onto untreated skin comprised the controls. Main Outcome Measure: Amount of dye extracted from the skin as reflected by absorbance spectrophotometry. Results: This multiple-barrier product inhibited the passage of the tracer into the skin significantly better than the other 2 products at all time points, except for 1 point in the elderly group. Conclusion: Noninvasive preclinical methods show that this prototype barrier cream inhibits the absorption onto the skin of a solution simulating the density and ionic strength of urine. The advantages and limitations of the methods are clarified and directions for clinical research are suggested.

The early experience of our unit with the technique of ipsilateral full thickness forearm skin grafting of the radial forearm flap donor site defect is described. The technique provides the advantages of a full thickness skin graft whilst avoiding the need to harvest skin from a remote area. We have compared the results with that of split skin grafts used contemporaneously for the same purpose in our unit; the advantages and disadvantages are outlined. Continued success has encouraged us to utilize this technique routinely with certain modifications which we describe.

The radial forearm osteocutaneous flap is arguably the best flap for the restoration of intraoral function following oromandibular reconstruction: As well having ample surface area, its skin is thin, supple, capable of providing separate paddles for lining and cover, and most importantly, capable of reinnervation for sensate oral reconstruction. The donor site is remote from the recipient, allowing a two-team approach without respositioning. The vessels are large and the pedicle is long. The bone is strong but its usable length is short. It lacks vertical height as well as bulk. In low-volume resections the cosmetic results are excellent, but the cosmetic outcome is less satisfactory when bulky tissue has been resected. Bony defects exceeding 10 cm are probably unsuitable for reconstruction with this flap. Forearm skin may be hairy, and when much is taken, the donor site scar is a conspicuous cosmetic defect. Overzealous harvesting of bone, inadequate postoperative splintage, unusual forces, or sheer bad luck can result in a fractured radius. Yet the flap is reliable and the rates of bony union are high. Donor defects may be minimized by meticulous surgical technique, limiting the bone graft to one third of the distal radial circumference, direct wound closure when possible, and appropriate postoperative splintage. Fractures of the radius are rare under these circumstances. With the correct indications, the radial forearm flap has a distinct and unique role to play in reconstructing composite oromandibular defects.

Hypnosis has been used to ameliorate skin test reactivity in studies dating back to the 1930s. This study using modern methodology and statistical analyses sets out to test the hypothesis that it was possible to decrease reactions to histamine by hypnotic suggestion. Five subjects, all asthmatic and untrained in hypnosis, were given three hypnotic sessions where they were asked to control their reactions to histamine administered by the Pepys technique to forearm skin. These sessions were to be compared with three non-hypnotic sessions. The flare sizes but not wheal sizes were found to be significantly reduced after the hypnosis sessions, compared to sessions without hypnosis. Skin temperature was correlated with the size of reactions. The day upon which the sessions took place contributed significant amounts of the remaining unexplained variance, giving rise to questions about what could cause these day to day changes.

We determined whether the ability to localize a single noxious cold versus innocuous tactile stimulus is associated with the ability to discriminate between two stimuli in the forearm skin of healthy human subjects. When single stimuli were applied, the localization of a noxious cold stimulus was at least as good as that of a tactile stimulus. With both of these modalities, the localization of a single stimulus was more accurate in the radial-ulnar than proximo-distal direction. In contrast to localization of a single stimulus, the discrimination of two cutaneous test stimuli from each other was an order of magnitude worse for noxious cold than touch. This dissociation indicates that localization of single cutaneous stimuli and discrimination of two cutaneous stimuli from each other are based on different mechanisms.

1. 1. The purpose of this study was to determine the effect of fiber type and fabric moisture content on SC hydration. 2. 2. Using three similarly constructed fabrics, six fabric type/moisture content combinations were selected. 3. 3. Fabric swatches were placed on both “normal” and “hydrated” volar forearm skin of five subjects for a specified period, then removed. 4. 4. Two minutes after removal, evaporative water loss (EWL) and skin temperature were measured. 5. 5. Data were analyzed using analyses of variance and Bonferroni t-tests. 6. 6. For normal skin, SC hydration generally increased as fabric moisture content increased. SC was significantly drier after being in contact with cotton swatches at regain than at the two moisture content levels above regain, and also under polyester swatches. 7. 7. For hydrated skin, hydration state was significantly lower under the cotton swatch at regain than at 38.6% moisture content or at saturation, but was not significantly different under the polyester swatch at regain or at saturation.

The principles of color measurement established by the Commission International d'Eclairage have been applied to skin and the results expressed in terms of color space L*, hue angle, and chroma values. The distribution of these values for the ventral forearm skin of a sample of healthy volunteers is presented. The skin-color characteristics of a European subgroup is summarized and briefly compared with others. Color differences between individuals were identified in terms of one, two, or all three color-space parameters. Because the method is quantitative and the principles internationally recognized, these color-space parameters are proposed for the unambiguous communication of skin-color information that relates directly to visual observations of clinical importance or scientific interest.

1. 1. To examine whether the increased hand blood flow (BF), mainly arteriovenous anastomoses (AVA) flow, limits an increase in other skin BF during thermal load, 7 healthy male subjects were exercised for 25 min and then rested for 20 min in wrist occlusion (OCCL) and control experiments (CONT), respectively. 2. 2. In OCCL, both wrists were occluded at pressure of 250 mmHg from the 15th min of exercise. 3. 3. In CONT, the wrists were free throughout the experiment. Finger and forearm skin temperature greatly increased in CONT, but did not rise in OCCL. 4. 4. Suppressed hand BF in OCCL induced compensatory increases of skin BF and sweat rate in the chest at least. 5. 5. However, wrist occlusion induced a significant rise in esophageal temperature and a significant fall in mean arterial pressure (MAP). 6. 6. These results suggest that the rising hand BF greatly contributes to limit the increase in other skin BFs without any fall of MAP during thermal load.

Intro&ction Areas of unburned forearm skin such as that protected by a watchstrap may be salvaged in an otherwise complete full thickness bum of the upper limb requiring amputation. Pedicled skin flaps raised on the ulnar or radial arteries can be used to cover forearm or above-elbow amputation stumps. A case is presented.

1. Yang G, Baoqi C, Yuzhi G. Free forearm skin transplantation. National Medical Journal of China 1981; 61: 139. 2. Soutar DS, Scheker LR, Tanner NSB, McGregor IA. The radial forearm flap: a versatile method for intra-oral reconstruction. Br J Plast Surg 1983; 36: 1–8. 3. Urken ML, Chenly ML, Sullivan MJ, Biller HF. Atlas of regional and free flaps for head and neck reconstruction. New York: Raven Press, 1995: 334–335. 4. Kim KA, Chandrasekhar BS. Cephalic vein in salvage microsurgical reconstruction in the head and neck. Br J Plast Surg 1998; 51: 2–7. 5. Nakayama Y, Soeda S, Lino T. A radial forearm flap based on an extended dissection of cephalic vein: The longest venous pedicle? Br J Plast Surg 1986; 39: 454–457. 6. Bhathena HM, Kavarana NM. Bipaddled, retrograde radial extended forearm flap with microarterial anastomosis for reconstruction in oral cancer. Br J Plast Surg 1988; 41: 354–357. 7. To EWH, Wang JCY. Radial forearm free flap: hybrid version. Plast Reconstr Surgery 1999; 104: 1066–1069.

SUMMARY Using a newly developed suction device, the mechanical properties of forearm and vulvar skin were studied in 22 healthy women, 12 before and 10 after the menopause. The ratio between viscous deformation (Uv) and elastic deformation (Ue) and the biological elasticity, i.e. the ratio between immediate recovery (Ur) and total deformation (Uf), were both significantly lower in vulvar than in forearm skin. Ur/Uf decreased significantly with load in vulvar, but not in forearm skin, whereas Uv/Ue was not load-dependent in either site. Uv/Ue remained constant with age in both test sites, whereas Ur/Uf was significantly lower in post-menopausal women in both forearm and vulvar skin. In vulvar, but not in forearm skin, Uv/Ue was significantly correlated with body height which may be an indicator of mechanical connective tissue properties. Viscous deformation plays a lesser role and biological elasticity is decreased in vulvar compared to forearm skin. Despite differences in mechanical parameters at both sites, age-related changes seem to be similar.

Forearm skin of Stage XXIV Rana pipiens , which cannot regenerate limbs, was removed and placed upon the skinned forearms of young axolotls. The axolotl limbs were amputated immediately through the level of the grafts. Frog epidermis migrated to cover the amputation surface. Dedifferentiation and early blastema formation occurred beneath the frog wound epidermis. Limb regeneration continued, but in time axolotl epidermis overgrew the frog epidermis. The experiment shows that epidermis from nonregenerating frog limbs is still capable of supporting typical epimorphic regeneration.

Three semi-permeable polyurethane dressings, 'Ensure', 'OpSite' and 'Tegaderm', were tested for their ability to prevent the increase in bacterial population under naturally hydrated, occluded volar forearm skin. Only 'OpSite' inhibited the bacterial multiplication in these tests. It is concluded that in the practical situation, 'OpSite' could well confer a greater margin of safety.

The acute and chronic consequences of subclavian artery transection were analyzed in the noninvasive vascular laboratory. Twenty-eight patients (aged 1 day to 42/12 years, median 2 months) underwent subclavian artery transection (23 Blalock-Taussig, four subclavian aortoplasty for coarctation or interrupted arch, and one division of aberrant left subclavian). Bilateral systolic brachial artery pressure (BAP) was measured by Doppler instrumentation to obtain a “BAP index”: BAP1 = (operated side BAP/control side BAP). Velocity waveform tracings and bilateral forearm skin temperatures were also obtained during studies before and sequentially after operation (4 hours to 12 years). Five patients underwent exercise testing of the upper extremity. Nine patients were studied for manual preference and limb development. Before operation, mean BAP, was 0.99. Immediately (4 to 48 hours) after operation, mean BAP, was 0.39. Three weeks postoperatively, BAP, was 0.62, and thereafter it remained at 0.70. All differences between preoperative, immediate postoperative and late postoperative BAP, are significant (p

A spring-loaded apparatus was designed to apply uniaxial tension to forearm skin in 17 human subjects--10 normals, 6 psoriatics, and 1 patient with scleroderma. Simultaneously, the effects of stretching on the upper dermal vasculature were observed stereomicroscopically. Progressive changes (collapse) in the superficial microvasculature--vertical capillary loops and horizontal subpapillary plexus--with increasing tension were photographed. Force and strains were recorded at the points of disappearance of virtually all vessels. An average force of 11.9 newtons (N), accompanied by a mean strain of 10.3%, resulted in occlusion of all vessels. A much higher force (18.5 N) was necessary to occlude blood flow in the 1 patient with scleroderma. In summary, we have described a new technique for the study of mechanical forces on the blood supply of the epidermis. The data have shown that uniaxial tension has important effects on the superficial dermal microvasculature, resulting in impedance and obliteration of blood flow at relatively low magnitudes.

A new animal model for in vivo percutaneous absorption utilizing the hairless, relatively thick skin of the guinea pig ear is proposed. Topical absorption studies were carried out with [14C]hydrocortisone and [14C]testosterone. Systemic studies were also conducted to correct for incomplete urinary excretion. In addition, a single stratum corneum correction factor was developed from published data to enable the guinea pig ear skin to be directly compared with human forearm skin. A comparison of human percutaneous absorption with the corrected guinea pig ear absorption shows a high correlation for both hydrocortisone and testosterone. The effects of ambient changes in relative humidity are also discussed with respect to in vivo percutaneous absorption.

The inside skin of the forearm of healthy volunteers was irradiated with an infrared (IR) lamp for 1 hr, resulting in the rapid appearance of an erythema and an elevation of skin surface temperature from 30 +/- 1 degree C to 38 +/- 2 degrees C within 5 min. The erythema and elevated skin surface temperature decayed within 10-30 min when the IR irradiation was stopped. Suction blisters were raised on nonirradiated skin and on irradiated skin both during irradiation and at various times after irradiation stopped. Elevated levels of free arachidonic acid, PGE2, PGD2, PGF2 alpha and 6-oxo-PGF1 alpha were found up to 24 h after irradiation. By 48 h the prostaglandin levels had returned to control values whereas the free arachidonic acid levels were still elevated at 72 h. The peak level of 6-oxo-PGF1 alpha appears between 0-6 h whereas for PGE2, D2, and F2 alpha it is between 6-16 h, suggesting a different cellular source for this prostaglandin.

Suction blisters were produced on forearm skin, and the oxygen tension on the surface and the base of such blisters was measured polarographically during the breathing of both air and oxygen. Estimates of the oxygen tension gradient across the epidermis were made from the measurements. The mean value was 28 mm Hg ± 4.6 S.D. The rates of fall of oxygen tension following occlusion of the blood supply during the breathing of oxygen were the same on the blister lid and the blister base, and were linear.