Strip Of Skin Research Articles

Combined method of autoallodermoplasty

In the treatment of extensive skin defects, when donor resources were insufficient for a one-step full replacement of the lost dermal cover, we used a new method of plastic surgery, which consists in combining the patient's skin and the donor's. A skin strip devoid of fatty tissue was cut out from a patient (its dimensions were calculated taking into account the area of ​​the wound surface), which was dissected with a scalpel, a straight razor or a special microdermatome into transverse auto-micrografts with a thickness of 0.1 to 0.5 mm. This significantly increased the area of ​​the main flap. The resulting grafts had two lateral surfaces capable of fusion with tissues. They contain all the elements of the skin, which allows us to call them full layer. The grafts were placed on the granulating surface with their lateral side with their moderate spreading at a distance of 4 mm from each other in a checkerboard pattern.

Repair of large midline abdominal-wall hernias by a running strip of abdominal skin.

Our experience with a full-thickness running strip of abdominal skin for the treatment of large midline abdominal hernias has been very positive. The mechanical properties of the skin strip allow one to reestablish a normal anatomy by bringing the rectus muscle in contact. Clinical and histologic studies have shown that the full-thickness skin rapidly loses its epidermal components and appears to transform itself into a dense connective tissue very similar to normal aponeurosis.

Viscoelastic behavior of human connective tissues: relative contribution of viscous and elastic components.

Stress-relaxation tests were performed at successive strain levels on strips of human aorta, skin, psoas tendon, dura mater, and pericardium. The elastic fraction, the equilibrium force divided by the initial force, was calculated at each strain increment. In the aorta, the elastic fraction decreased with strain and was modeled as the transfer of stress from elastic to collagen fibers, while in skin it increased with strain, probably due to the rearrangement of individual collagen fiber orientations, resulting in an aligned collagen network at high strains. The strain-independent elastic fractions for tendon, dura mater, and pericardium were similar, and approximately equal to the values found for aorta and skin at high strains. It was hypothesized that the elastic fraction is related to the type of fiber loaded, and the tissue geometry. This analysis may be useful in studying disease-induced changes in the mechanical properties of connective tissues.

Pattern regulation between hind- and forelimbs after blastema exchanges and skin grafts in Notophthalmus viridescens.

Experiments were performed to ascertain whether cells from the forelimb and the hindlimb of newts share a common pattern-regulating mechanism during regeneration. In one series of experiments early digit hindlimb and forelimb blastemas were exchanged either ipsilaterally or contralaterally. In a second experimental series, a strip of forelimb skin was added to a slit in a homologous site on the hindlimb or in a site 180 degrees removed from the position of origin, and vice versa (hindlimb skin into forelimb). After contralateral blastema exchanges, supernumerary limbs developed in addition to the limb of graft origin, whereas after ipsilateral exchanges, a single limb of graft origin regenerated. Limbs in which skin grafts were inserted into homologous sites developed normal regenerates of the host type, while in contrast, limbs with supernumerary digits regenerated from limbs which had received skin grafts in positions 180 degrees opposite to the homologous position. The results of both experiments were dependent on the positional disparity between the graft and host tissues, and they suggest that the forelimb and hindlimb do indeed utilize a common mechanism for pattern regulation.

The Response of Human Skin to Small Tensile Loads in Vitro

The mechanical properties of excised strips of human skin were investigated in the initial high compliant phase. The specimens showed preconditioning on repeated load cycling. The preconditioned specimen displayed a reproducible response, and a region of linear load-extension behaviour. The value of the tensile modulus and Poisson's ratio, both referred to the dimensions of the preconditioned specimens, are reported and the tissues shown to be anisotropic. Stress relaxation tests showed the properties of the tissues to be time dependent.

A new technique for areolar reconstruction

A new technique for areolar reconstruction is presented. Donor areolar tissue is preferred, but groin or thigh skin may be used. The modification of this procedure is the placement of a strip of areolar skin as a circular mesh, so that small amounts of tissue may be used to give an irregular surface. To restore the size of the donor areola, the same principle is applied by outward expansion of the remaining areolar tissue. If the areola is small, we prefer to make the reconstruction bilateral.

Posterior neck lift for correction of sagging of the lower anterior neck

The posterior neck lift is described as part of an overall rhytidectomy for tightening the skin of the lower anterior neck. A wide horizontal strip of skin is excised along the entire nape of the neck. Closure of the resultant defect is obtained by raising the posterolateral neck skin, which in turn has a direct effect in overcoming laxity of the lower anterior neck. The plane of dissection is in the fibrofatty tissues. The operation is easily performed and has not been associated with any untoward complications. It relies only on skin traction without any platysma muscle plasty being undertaken.

Dose-survival relationship for epithelial cells of human skin after multifraction irradiation: evaluation by a quantitative method in vivo

The dose-survival relationship for normal epithelial cells after single and fractionated radiation exposures has been established by Withers for the mouse, 11 but it is not available for humans according to a strict criterion for survival of single cell reproductive integrity. In an attempt to obtain such a quantitative estimation, 2 patients requiring radical radiation therapy to the chest wall were treated according to particular Multiple Daily Fractionation (MDF protocols i) 250 + 150 + 150 rad/day, 4 hr interval, 5 days/week; and ii) 150 + 150 + 150 + 150 rad/day, 3.5 hr interval, 5 days/week. In both cases, different strips of skin received different total doses: 6300, 6850, and 7150 rad, and 6300, 6750, and 7200 rad, respectively. In case (i), moist desquamation appeared and thereafter repopulating colonies of epithelium could be recognized and counted. Using these counts a survival curve having a D 0 value of 490 ± 150 rad was estimated according to the formula proposed by Withers. 11 In case (ii), no moist desquamation was reached at the doses delivered. The difference observed may imply that the initial region of the survival curve deviates appreciably from exponential between doses of 150 and 250 rad. If such is the case, a 1 D 0 value of 490 rad may represent an underestimate. These results are discussed from the point of view of both the shape of the survival curve and the effectiveness of nonconventional fractionation courses.

The influence of a local injection of cortisol on the mechanical properties of tendons and ligaments and the indirect effect on skin.

The effects of local cortisol treatment on the mechanical properties of muscle tendon and ligament in rats were studied. In addition to the local effects, possible systemic effects as reflected in the properties of the skin, remote from the site of the injection, were investigated. Two groups of rats were given cortisol injections, 20 mg/kg, every third day for 24 days. In one of the groups the injections were given bilaterally around the peroneal tendons and in the other they were given into both knee joint cavities. Specimens from the peroneal tendons, the posterior cruciate ligament with bone attachments, and strips of skin from the dorsum, were tested in a materials testing machine. The local treatment resulted in increased "tensile strength" of the peroneus brevis tendon and increased maximum load and stiffness of the peroneus longus tendon with no change in the collagen content in any of the samples. The posterior cruciate ligament always broke at one of the two sites of attachment to the bone and the maximum load value at these points was decreased after local cortisol treatment. The systemic effects of this local cortisol treatment on the skin were decreased thickness and fat content, increased collagen concentration and higher "tensile strength" and failure energy. From this study it is concluded that local cortisol injections for 24 days increase the strength and stiffness of muscle tendons, but decrease the strength of the bone attachments of ligaments. This treatment also results in a systemic effect which shows itself as increased strength of the skin remote from the site of the injections.

Dose survival relationship for epithelial cells of human skin after multifraction irradiation: Evaluation by quantitative method [formula omitted

The dose-survival relationship for normal epithelial cells after single and fractionated radiation exposures has been established by Withers for the mouse,” but it is not available for humans according to a strict criterion for survival of single cell reproductive integrity. In an attempt to obtain such a quantitative estimation, 2 patients requiring radical radiation therapy to the chest wall were treated according to particular Multiple Daily Fractionation (MDF) protocols: i) 250 + 150 + 150 rad/day, 4 hr interval, 5 days/week; and ii) 150 + 150 + 150 + 150 rad/day, 3.5 hr interval, 5 days/week. In both cases, different strips of skin received different total doses: 6300,6850, and 7150 rad, and 6300, 6750, and 7200 rad, respectively. In case (i), moist desquamation appeared and thereafter repopulating colonies of epithelium could be recognized and counted. Using these counts a survival curve having a D,, value of 490 + 150 rad was estimated according to the formula proposed by Withers.” In case (ii), no moist desquamation was reached at the doses delivered. The difference observed may imply that the initial region of the survival curve deviates appreciably from exponential between doses of 150 and 250 rad. If such is the case, a ,D, value of 490 rad may represent an underestimate. These results are discussed from the point of view of both the shape of the survival curve and the effectiveness of nonconventional fractionation courses.

Construction of epithelialised tubes

The construction of an epithelialised tube from a buried split skin strip and the free transfer of the constructed tube are described in animal experiments.

An attempt to reduce the visible scar in primary cleft lip repair

MODERN cleft lip surgery attempts to provide a nose and lip which are normal in function and appearance. Unfortunately the result is often marred by a noticeable scar, however fine it may be. In some patients the scar draws attention to the lip due to broadening, depression or a poor colour match with the adjacent skin. An attempt has been made to reduce the visible scarring in the repaired lip using an idea based on a simple observation made during the treatment of facial abrasions and lacerations: wounds confined to the epidermis and superficial layers of the dermis healed without visible scars but those which penetrated more deeply, particularly if they reached the fat, always left noticeable scars. It was considered that, if the repair of a cleft lip could be designed so that the only visible portion of the repair was confined to the superficial layers of the skin, it might be possible to hide the main scar. It was assumed that the skin of the lip would be sufficiently opaque to hide the scar and that a wedge-shaped strip of skin (without subdermal fat) would survive on the dermal plexus.

Determination of the impedance of the guinea pig skin.

The impedance of guinea-pig skin has been studied using anin vitro method which consists of placing the recording chamber containing a strip of guinea-pig skin in the feedback branch of a closed-loop amplifier having an adjustable resistor in its input circuit. The chamber consists of two cylinders filled with a circulating Krebs solution at 37°C and two platinum electrodes facing one another inside the cylinders. At a given frequency, the series resistor is adjusted to obtain a gain of unity between input and output sinewave voltages (gain=10). The value of the series resistor is then equal to the modulus of the impedance in the feedback loop and its argument is calculated by a phase/amplitude convertor on the basis of the input and output phase shift. The impedance measurement is made separately for the recording chamber and the whole system in which the tissue is inserted. Substracting vectorially both values obtained enables the impedance of the tissue itself to be deduced. This procedure is repeated over a wide frequency band and the resulting values are represented on a Bode diagram of phase and amplitude. The Bode diagram shows the variations of the electrical characteristics of the tissues as the frequency varies, and indicates nonlinear filtering especially for low-frequency values (10−2 Hz).

Relay transplantation: A new method of expanding a free skin graft

A method of skin transplantation is presented whereby a wound may be successively sown with epithelium by the repeated transfer of the same strips of split thickness skin.

Influence of concomitant treatment with D-penicillamine and beta-aminopropionitrile on mechanical properties of rat connective tissue (author's transl)

In order to study the influence of D-penicillamine (DPA) and beta-aminopropionitrile (BAPN) as well as of a combination of both substances (proportion by weight 1:1) on the collagen of skin, aorta, and femoral epiphysial cartilage, the mechanical properties of these fibrous organs were examined, after having performed tests on onset and dissipation of action, measured by the decrease of ultimate load of excised strips of skin using the two individual compounds. The action of 320 mg/kg of DPA sets in within 7 days reaching a maximum value after 14 days. After discontinuance of the substance the control values are reached within 15 days. BAPN shows its maximal effect on the 18th test day. After discontinuance of treatment the control value is not reached within 35 days. DPA and BAPN show organo-specific actions: DPA has a considerably stronger influence on the collagen of skin than on the collagen of the aorta; under the present test conditions it does, however, not affect the collagen of the distal femoral epiphysial cartilage. As compared to DPA, BAPN exerts a less pronounced influence on the collagen of the skin, similar influence on the collagen of the aorta, and a strong influence on the collagen of the distal femoral epiphysial cartilage. If both substances are administered together, the organospecific actions of DPA on the one hand and BAPN on the other hand are maintained. It is discussed whether the different chemical compositions of the collagen (Type I--IV) may be connected with the organospecific effects of the test substances.

Extrinsic nerve supply of the naked rhinarium in the tree shrew.

The extrinsic nerve supply of the median strip of skin in the naked rhinarium of the tree shrews (Tupaia glis) was studied by means of nerve section. Experiments were designed, where the external nasal nerves, infraorbital nerves or a combination of both were sectioned. The cholinesterase and silver impregnation techniques were employed to demonstrate intraepithelial nerves, mammalian end-organs, and the dermal nerve plexus before and after denervation. These experiments have given results contrary to what was expected, as the skin in this region, which develops from the frontonasal process, was found to be supplied by the infraorbital nerves (branches of the maxillary division of the fifth cranial nerve, which is the nerve of the maxillary process) and not the external nasal nerves (branches of the ophthalmic division of the fifth cranial nerve, the nerve of the frontonasal process).

Morphogenetic interactions between rotated skin cuffs and underlying stump tissues in regenerating axolotl forelimbs

Rotation of skin cuffs 180° around the longitudinal axis of the underlying tissues in the axolotl forelimb results in a high percentage of multiple regenerates after amputation through the rotated skin. Similar results occur after rotation of only the anteroposterior (A-P) axis of the skin. Rotation of only the proximodistal (Pr-Ds) axis of the skin results in normal regenerates whereas dorsoventral (D-V) axial skin rotation results in single regenerates with some disturbances in symmetry. Rotation of anterior or posterior half cuffs of skin produces results similar to those obtained after A-P rotation of full skin cuffs, and rotation of dorsal or ventral skin halves duplicates the results obtained by rotating full skin cuffs about the D-V axis. Skin cuffs rotated for periods from 6 months to over 2 years before amputation are also capable of causing multiple regenerates to form. No significant difference in the percentage of multiple regenerates was seen after skin rotation and limb amputation through shoulder, upper arm, and forearm levels. X-Radiation (4000 r) of either the skin or underlying tissues before skin rotation resulted in single regenerates after amputation. If a strip of normal skin was turned perpendicularly to the long axis of the irradiated underlying stump tissues, the regenerative response was blocked. In some of the above experiments, regenerates with longitudinally duplicated upper arm and forearm segments appeared. It is postulated that normally both the skin and the underlying limb tissues can influence morphogenesis during regeneration and that they work in harmony. In contrast, rotated skin and the underlying tissues each exert a morphogenetic influence upon the regenerating limb, and the regenerate is not able to integrate these disharmonious influences. This is reflected in the highly abnormal morphology of the regenerates. The nature of the morphogenetic influence disrupted by skin rotation is not yet known.

Studies on detection and synthesis of prostaglandins in tail skin of the rat.

AbstractStudies are reported on the detection and in vitro biosynthesis of prostaglandins of the E type in the tail skin of male Sprague‐Dawley rats. It was found that strips of skin were preferred to other techniques of skin preparations, such as mincing or homogenization for the assay of endogenous prostaglandins. Each strip of tail skin could be used at least twice, each time in fresh buffer to obtain additional release of endogenous prostaglandins. The skin was stripped from a longitudinal incision in the tail in one piece and cut into four parallel strips lengthwise. Each strip of skin was incubated singly and the prostaglandins were extracted with ethyl acetate. The detection and analysis of prostaglandins of the E type were carried out by standard procedures on the residue of this extract dissolved in 95% ethanol. By means of this technique, endogenous prostaglandins were detected in the tail skin of rats. Little or no prostaglandins were extracted by organic solvents directly from the tissue, and the yields were low when the tissue was minced. The results indicate the possibility that endogenous prostaglandins may be synthesized during incubation in buffer or may be released from binding with other cellular components. The major prostaglandin of this tissue was PGE2; prostaglandin E1 (PGE1) was also detected. Using the same procedure, the presence of a prostaglandin synthetase system in the tail skin was demonstrated by the conversion of exogenous arachidonic acid to prostaglandin E2 (PGE2).

Replantation of almost completely amputated thigh with recovery

A twenty year old woman had transection of all the structures of the distal right thigh except for the sciatic nerve, the vastus lateralis muscle, and a small strip of skin. Successful replantation with excellent functional result was attributed to several fortuitous factors: (1) most importantly, an intact sciatic nerve; (2) the youth of the patient; (3) presence of a minimal amount of collateral circulation which, although not enough to maintain the viability of the limb, perhaps bought time for the tissues during the prolonged period of ischemia. Important technical factors in replantation include: (1) careful debridement; (2) accurate anastomosis of the vein and artery; (3) adequate fasciotomies of the anterior and posterior muscle compartments of the leg; (4) adequate internal fixation of the comminuted compound fracture; (5) intravenous administration of large amounts of balanced electrolyte solution and correction of blood loss; (6) massive doses of penicillin and streptomycin.

Two-stage urethroplasty for stricture: results and technical considerations.

SUMMARY Forty-four patients who underwent the two-stage urethroplasty employing the buried skin strip principle are reviewed. Follow-up extended from one to five years. Urinary drainage was by urethral catheter in all cases. Good results were obtained in 81 per cent. overall, and in 92 per cent. of the last 27 cases. The causes of failure are analysed and the technique necessary to obtain “good” results outlined: 1 Recurrences of stricture are primarily due to incomplete division of the original stricture. Panendoscopy at operation is essential in defining the extent of the stricture. 2 Diverticula are due to improper cutting of the urethral flaps at the second stage and can be avoided if a No. 20 sound is used as a guide. 3 Stitches in the urethra or in the urethral skin flaps are completely unnecessary and probably harmful.