Gas flux through human skin: effect of temperature, stripping, and inspired tension

The flux of He and O2 through intact adult human skin was measured at various inspired concentrations and skin temperatures. The skin surface was then stripped with cellophane tape to alter the diffusional conductance of the stratum corneum. He flux for stripped skin was used to estimate skin perfusion as a function of local temperature, and diffusional conductance for O2 was estimated from O2 flux and perfusion. The flux of He or O2 at constant skin temperature can be related to inspired concentration by a simple linear model. Increasing surface temperature in the range 33-43 degrees C produced a much larger increase in O2 flux than in He flux for intact skin. Skin stripping greatly increased skin O2 flux. Estimated skin conductance for O2 showed a more marked temperature dependence than estimated skin perfusion. The results suggest that raising skin temperature in the range 38-43 degrees C has only a modest effect on skin perfusion and that stratum corneum conductance may have a major role in the large increase of O2 flux with temperature.     

Tension decrease during skin stretching in undermined versus not undermined skin: an experimental study in piglets

In a controlled study using 15 piglets, the efficacy of skin stretching using a skin stretching device was tested by quantifying the tension decrease during skin stretching in undermined and not undermined wounds. The viability of the skin margins was examined in both situations. Thirty standardized wounds was created: around 15 wounds on one flank, the surrounding skin was undermined; whereas around the 15 wounds on the opposite flank, the surrounding skin was not undermined. The force required to close the 9 x 9 cm defect was measured at the beginning, after undermining, and after 30 minutes of skin stretching. Also examined was the wound healing after 1 day and 1 week. A tension decrease of 3.02 N (13.6 percent reduction of the total force that is required to close the wound at the beginning) was seen due to undermining the surrounding skin. Skin stretching for 30 minutes without undermining the skin showed a tension decrease of 6.10 N (26.5 percent). Therefore, the tension decrease due to skin stretching was twice as high in comparison with undermining the skin margins alone. This has been statistically proven to be significant (-d (difference) = 3.08, 95 percent confidence interval = 2.16; 4.00, p < 0.001). When the undermined skin of the wound was stretched for 30 minutes, we measured a total tension decrease of 7.60 N (34.1 percent). There was a statistically significant but small difference in total tension decrease as a result of undermining combined with skin stretching in comparison with skin stretching without undermining (-d = 1.51, 95 percent confidence interval = 0.77; 2.23, p < 0.001). Undermining the surrounding skin involved cutting musculocutaneous perforating vessels. Looking at the viability of the skin, seven wounds, all found in the undermined group, showed skin necrosis after 1 week. Excessive seroma formation was seen in all wounds around which the skin was undermined. In the not undermined wounds, there were no problems in wound healing. In conclusion, skin stretching for only 30 minutes using a skin stretching device significantly reduces wound closing tension. The additional advantage of skin stretching over that of undermining alone is clearly shown. Undermining the wound margins before skin stretching gives a small additional tension decrease but has well-known complications, such as skin-edge necrosis and seroma formation.     

Skin preservation at 4 degrees C: a species comparison

There are numerous experimental studies in the literature regarding skin storage and preservation. These studies are difficult to interpret due to the variety of storage techniques utilized and the number of different animal species used as skin donors. This study utilized a single cold storage protocol to test the effect of species variation on skin graft viability. Donor skin was obtained from five animal species and human surgical panniculectomy specimens. The skin was stored in modified Roswell Park Memorial Institute (RPMI) 1640 tissue culture media at 4 degrees C. Stored skin was transplanted to surgically created defects on athymic (nude) mice after specific storage intervals. Ten days after transplantation, the grafts were examined by gross and microscopic techniques. The viability of mouse, rat, and dog skin was significantly different from human skin, while stored rabbit and pig skin were similar to human skin. These results demonstrate the difficulty of applying the data of skin storage studies from nonhuman species to clinical practice. The data indicate that rabbit and pig skin may be used in laboratory studies of skin preservation at 4 degrees C with a strong likelihood that the results may be of clinical relevance in predicting the behavior of human skin under similar storage conditions.     

负压封闭引流技术在躯干部皮肤恶性肿瘤切除术中的应用

目的:探讨负压封闭引流技术应用于躯干部皮肤恶性肿瘤切除术的临床效果,并分析其临床应用价值。方法:回顾性分析2012年5月~2015年3月我院收治的11例躯干部皮肤恶性肿瘤患者的临床资料,均予行肿物切除术并同时行自体皮游离移植术,并外用持续负压封闭引流术于植皮术区。结果:所有患者均接受肿物切除+植皮+封闭负压引流技术治疗。9例患者于4~9天后拆除负压材料,皮片全部成活。1例患者治疗后24小时内吸引管堵塞,经术后于24小时内行管路冲洗疏通后再次行负压吸引,于术后5天首次拆除负压材料,见皮片部分成活,部分皮片仍有浮动,血运未明显建立,予以扩大皮片引流孔后再次行负压封闭引流术,术后9天再次拆除负压材料,见皮片成活较好。1例患者治疗4天后出现新鲜渗血经引流管引出,予拆除负压材料,所植皮片下有积血块,有新鲜渗血,予以清创后再次行负压封闭引流术,术后9天再次拆除负压材料,见皮片成活较好。随访半年到3年,所植皮片无破溃,肿瘤无复发。结论:躯干部皮肤恶性肿瘤切除术中,植皮联合封闭式负压引流技术可使所植皮片固定确实,充分引流渗液积血,利于皮片成活,对无法有效包扎固定肢体特殊部位(肩部、臀部、躯干部)等术区植皮提供了有效方法,具有一定的推广应用价值。     

Oxygenation and microcirculation during skin stretching in undermined and nonundermined skin

The aim of this experimental study was to assess the skin microcirculation of undermined and nonundermined wound edges closed with a skin-stretching device. In eight piglets, 9 x 9-cm wounds were created on both flanks by excision of the skin and the subcutaneous layer down to the muscular fascia, with general anesthesia. On one flank, the surrounding skin was completely undermined. For a period of 30 minutes, wound closure was performed with a stretching device, using the principle of load cycling. The device stretched the skin and moved the opposing wound edges toward each other. During this period, laser Doppler flowmetry and transcutaneous oximetry were simultaneously used to monitor microcirculation and oxygenation in the stretched skin of both flanks. Undermining of the surrounding skin produced a 12 percent decrease in the laser Doppler flowmetry signal and a 21 percent decrease in the transcutaneous oximetry value. Skin stretching resulted in decreases in the laser Doppler flowmetry signals and the transcutaneous oximetry values, whether or not the skin was undermined. Releasing the stretching device resulted in rapid normalization of the laser Doppler flowmetry values in undermined and nonundermined skin and a slow return of the transcutaneous oximetry values to close to baseline levels in nonundermined skin. The transcutaneous oximetry values in undermined skin did not return to baseline levels; each period of skin stretching resulted in an additional decrease in the transcutaneous oximetry values. Stretching of undermined skin for 30 minutes produced a significant (p < 0.0001) decrease in skin oxygenation. As a result, 50 percent of the undermined stretched skin demonstrated skin necrosis at the wound edges, which was still present after 1 week. Wound healing in the nonundermined stretched skin proceeded without problems. It is concluded from these experiments that the viability of undermined skin becomes compromised as a result of significantly decreased oxygen availability in the skin during and after stretching. Consequently, it is recommended that skin stretching be performed on nonundermined skin, rather than undermined skin. In addition, when skin is stretched to close a large defect, it is logical to use cyclic loading, so that recuperation of the skin circulation can occur. Furthermore, laser Doppler flowmetry seemed to produce atypical signals in monitoring of skin viability of wound edges closed with a skin-stretching device.     

皮肤的光学模型

基于人体皮肤的组织结构,光在皮肤组织中的传输特性以及皮肤各层的组织光学参数,建立了正常皮肤的光学模型,介绍了该模型中的组织光学参数的确定方法。本文建立的皮肤组织光学模型及其方法,可应用于皮肤光学基础与临床的其它研究中。     

Comparison of skin permeability of drugs in mice and human cadaver skin

In vitro percutaneous absorption of four antihypertensive drugs were carried out across the mice and human cavader skin in order to compare their skin permeability. An interesting trend was noticed in these experiments. Poorly water soluble drug prazosin hydrochloride showed 13 times enhanced flux in the mice skin whereas the steady-state flux of the water soluble drug propranolol hydrochloride was almost same in both human cadaver and mice skin. The permeation rate of prazosin hydrochloride and propranolol hydrochloride through the human cadaver skin fluctuated widely over time, but in mice skin, distinct trends were noticed. The study indicates that the overall permeation rate in mice skin is higher than that in the cadaver skin and the meeting of the target-flux in mice skin does not guarantee its good permeability in human skin.     

Dolphin skin as a natural anisotropic compliant wall

Although the success of compliant walls in mimicking dolphin skin is well known, the drag-reducing properties of a dolphin's skin are still unclear. Moreover, little is known about the relation between the 3D structure of the skin and the local flow conditions. To study the role of a dolphin's skin in reducing the drag the skin morphology parameters were compared with the parameters of an anisotropic compliant wall and a possible flow-skin interface was considered. The 3D structure of skin from different locations was modelled using serial histological sections of the skin. The hydrodynamics of the dorsal fin of the harbour porpoise was studied by means of computer simulation of the flow around virtual models of the fin. It was found that the distribution of the skin morphology parameters is correlated with the local flow parameters on the fin surface. The skin structure appears to allow the flow-skin interface to behave similar to an anisotropic compliant wall in the regions of favourable and adverse pressure gradients on the fin. The relation founded between the skin morphology and the local flow parameters could be useful in the design of multipanel anisotropic compliant walls.     

Human skin permittivity determined by millimeter wave reflection measurements

Millimeter wave reflection from the human skin was studied in the frequency range of 37-74 GHz in steps of 1 GHz. The forearm and palm data were used to model the skin with thin and thick stratum corneum (SC), respectively. To fit the reflection data, a homogeneous unilayer and three multilayer skin models were tested. Skin permittivity in the mm-wave frequency range resulted from the permittivity of cutaneous free water which was described by the Debye equation. The permittivity increment found from fitting to the experimental data was used for determination of the complex permittivity and water content of skin layers. Our approach, first tested in pure water and gelatin gels with different water contents, gave good agreement with literature data. The homogeneous skin model fitted the forearm data well. Permittivity of the forearm skin obtained with this model was close to the skin permittivity reported by others. To fit reflection from the palmar skin with a thick SC, a skin model containing at least two layers was required. Multilayer models provided better fitting to both the forearm and palmar skin reflection data. The fitting parameters obtained with different models were consistent with each other.     

Evaluation of changes in selected skin parameters under the influence of extremely low temperature

The aim of the work was to evaluate changes in selected skin parameters under the influence of low temperature. The tests were conducted on a group of 20 women using whole-body cryotherapy. The average age of participants was 58.7 ± 7.54 years; the average body weight 77.84 ± 16.01 kg, the mean BMI 30.14 ± 5.81, and the average body height 160.7 ± 6.48 cm. The tested parameters included hydration, lubrication, temperature, and pH of the skin. The skin measurements were made on the first and tenth treatment days, before and after leaving the whole-body cryo-chamber. To assess the data collected before and after the experiment, the measurement taken at each time point were compared. After a series of ten treatment sessions, the greatest decrease was observed in skin hydration and skin temperature. No significant differences were noted for lubrication and skin pH. The analysis showed statistically significant differences in skin parameters between all measurement locations; the upper and lower limbs responded more significantly to cold than other parts of the body. It was also found that the facial skin was more lubricated and hydrated compared to other measuring locations. We conclude that varies skin parts respond differently to low temperature. Cryotherapy causes a significant decrease in temperature and hydration of the skin whereas differences in pH and lubrication of the skin remain insignificant.     

爪鲵呼吸器官的胚后发育

应用石蜡切片和扫描电镜技术,对爪鲵(Onychodactylus fischeri)幼体、亚成体和成体3个不同发育阶段的皮肤、外鳃、咽等呼吸器官进行了显微观察与比较分析,旨在揭示爪鲵不同发育阶段各呼吸器官的演化规律.结果表明,爪鲵的皮肤随年龄的增长而逐渐增厚,幼体阶段其背腹皮肤厚度相差不大,亚成体及成体背部皮肤明显厚于腹部;外鳃是幼体和亚成体爪鲵呼吸器官的重要组成部分,随着发育外鳃逐渐完善,到亚成体阶段达到顶峰,随后逐步退化;咽部是爪鲵的重要呼吸器官,幼体期口腔和咽发育不完善,亚成体咽部逐渐发育,至成体时发育完善.     

花背蟾蜍蝌蚪皮肤的结构与发育

为研究花背蟾蜍(Bufo raddei)蝌蚪在变态发育期皮肤的显微结构特点,选取G19、G22、G26、G36、G41、G43和G46共7个发育期蝌蚪的连续石蜡切片及成体的背部皮肤切片,采用H.E和AB-PAS染色方法,观察了皮肤各层结构的发育时序并进行了相应的测量.结果表明,在G19、G22和G26蝌蚪表皮均为1层细胞;G36蝌蚪皮肤细胞形态和层数在背腹部出现了显著的区别;在G41基本完成了表皮2层细胞的构建;G43期完成完整的真皮构建,其中分布有毛细血管和2种皮肤腺.G46皮肤在厚度、腺体和毛细血管分布等方面表现出了明显的区域性差异,并与成体皮肤结构有明显的差别,显示出蝌蚪在发育过程中皮肤结构的变化与其生存环境之间紧密的关联性.     

Developing Skin Analogues for a Robotic Octopus

In order to fabricate a biomimetic skin for an octopus inspired robot,a new process was developed based on mechanical properties measured from real octopus skin.Various knitted nylon textiles were tested and the one of 10-denier nylon was chosen as reinforcement.A combination of Ecoflex 0030 and 0010 silicone rubbers was used as matrix of the composite to obtain the right stiffness for the skin-analogue system.The open mould fabrication process developed allows air bubble to escape easily and the artificial skin produced was thin and waterproof.Material properties of the biomimetic skin were characterised using static tensile and instrumented scissors cutting tests.The Young's moduli of the artificial skin are 0.08 MPa and 0.13 MPa in the longitudinal and transverse directions,which are much lower than those of the octopus skin.The strength and fracture toughness of the artificial skin,on the other hand are higher than those of real octopus skins.Conically-shaped skin prototypes to be used to cover the robotic arm unit were manufactured and tested.The biomimetic skin prototype was stiff enough to maintain it conical shape when filled with water.The driving force for elongation was reduced significantly compared with previous prototypes.     

慢性湿疹患者皮损、鼻粘膜需氧微生物群的定位、定量研究

本文首次应用定位、定量方法对23例小腿部慢性湿疹患者皮损、邻近皮肤及鼻孔的菌群,从微生态学的角度进行探讨,并将结果同24例正常人小腿皮肤及鼻孔的菌群做了比较。其结果表明:金黄色葡萄球菌为皮损及邻近皮肤的主要菌种,并且其分离率及密度有按正常皮肤、邻近皮肤、皮损依次增高现象;类白喉杆菌的数量在皮损部位明显低于正常皮肤与邻近皮肤;表皮葡萄球菌分离率皮损及邻近皮肤均明显降低。本组结果同正常对照组相比其皮肤微生物群菌谱虽无不同,但其数量的变异是显著的,这对探讨湿疹的病因及用生态制剂等调整皮肤菌群使其恢复微生态平衡达到防治目的有所裨益。     

Split-thickness skin grafting of the myelomeningocele defect: a subset at risk for late ulceration

The appropriate method and timing of the management of the myelomeningocele defect have prompted considerable discussion. Use of split-thickness skin grafts acutely has accomplished wound closure with low morbidity and mortality. This study was designed to address the question of long-term suitability of the technique of split-thickness skin grafting of the myelomeningocele patient. The incidence of late and/or severe skin ulceration and the presence of gibbus deformity were correlated with the method of skin closure. Long-term follow-up revealed a higher incidence of chronic skin ulceration in the split-thickness skin graft group as compared with the primary closure group. All skin breakdowns appeared in the presence of a gibbus deformity, and gibbus deformity was more prevalent in the split-thickness skin graft group. The incidence of skin ulceration and gibbus deformity was site-dependent. A thoracic or thoracolumbar myelomeningocele repair with split-thickness skin graft was significantly more likely to be complicated by skin problems than the defect in the lumbar, lumbosacral, or sacral region. This relationship was secondary to the frequency of gibbus deformity in the more cephalad defects than defects caudad. A treatment plan is outlined that is based on the primary variable of the location of the myelomeningocele and secondarily by defect size.     

Interstitial-tissue localization of high-molecular-weight kininogen in guinea-pig skin

A rabbit antibody against the light-chain of guinea-pig high-molecular-weight (HMW) kininogen, which was specific to HWM kininogen and did not recognize low-molecular-weight kininogen, was prepared. This antibody demonstrated the presence of HMW kininogen antigen at the interstitial-tissue space in the guinea-pig skin by means of immunohistochemistry. The interstitial-tissue HMW kininogen antigen was extracted from the skin. This antigen molecule in the skin extract behaved identically as HWM kininogen of plasma in slab-polyacrylamide gel electrophoresis under the presence of sodium dodecyl sulfate followed by immunoblotting. Therefore, it was concluded that HMW kininogen was present in the interstitial-tissue fluid in the skin. The amount of HMW kininogen in the skin extract was quantified by a sandwich enzyme-linked immunosorbent assay with the anti-light-chain antibody and a goat anti-guinea-pig HMW kininogen antibody. On the assumption that the interstitial-tissue volume is 50 ml/100 g wet skin tissue, the average concentration of HMW kininogen in the interstitial-tissue fluid of the skin was calculated to be 23% of the plasma concentration. On the other hand, the proportion of intravascular HMW kininogen (derived from blood remaining in the vessels of the harvested skin) in relation to the total HMW kininogen in the skin extract was quantified by measuring the radio-labelled HMW kininogen which had been injected intravenously as a tracer of the intravascular HMW kininogen. About 5% of the total HMW kininogen in the skin extract was calculated to be derived from the intravascular blood volume of the skin, indicating that the majority of the HMW kininogen in the skin extract was derived from the extravascular-tissue space.     

重建组织工程化皮肤生物学功能研究

皮肤是人体最大的器官,易受到内外异常因素的损害而导致各种创伤。组织工程化皮肤为促进皮肤创伤修复起了很大的作用,但由于组织工程化皮肤只具备生理皮肤的相似结构,不具备其正常生物学功能,不能实现患者对皮肤创伤实现“完美愈合”的理想,难以广泛应用于临床。因此,构建具有生物学功能的理想人工皮肤是皮肤组织工程研究的重要课题。总结了当前组织工程化皮肤的缺陷,提出构建具有生物学功能人工皮肤的策略。     

GPR143在绵羊皮肤组织中的表达及定位分析

G蛋白偶联受体143(G-protein coupled receptor143, GPR143)在黑素体的生物合成中起重要作用,本文旨在研究GPR143基因在不同毛色绵羊皮肤组织中的差异表达及定位,探索GPR143基因与毛色形成的相关性。通过qRT-PCR方法和免疫印迹方法分别检测不同毛色绵羊皮肤组织中GPR143基因mRNA水平和蛋白水平的表达差异;运用免疫荧光法对不同毛色绵羊皮肤组织中的GPR143基因进行定位并对结果进行光密度值分析。qRT-PCR结果显示,GPR143基因在黑色绵羊皮肤组织中mRNA相对表达量为白色绵羊的7.84倍,二者差异极显著(P<0.01);免疫印迹结果显示,黑色绵羊皮肤组织中GPR143蛋白表达量是白色绵羊的1.3倍,二者差异显著(P<0.05)。免疫荧光结果显示,GPR143蛋白的主要表达部位为绵羊皮肤组织毛囊外根鞘和表皮层,经光密度值分析后发现,GPR143在黑色绵羊皮肤毛囊外根鞘和表皮层的表达量显著高于白色绵羊。本研究结果表明不同毛色绵羊皮肤组织均能表达GPR143基因,但黑色绵羊皮肤组织中该基因的mRNA和蛋白水平都显著高于白色绵羊,说明GPR143的mRNA和蛋白在黑色绵羊皮肤组织中表达上调,在白色绵羊皮肤组织中表达下调。GPR143基因可能通过调控MITF水平和黑素体的数量、大小、运动和成熟进而参与绵羊毛色的形成过程。     

Role of human skin in the photodecomposition of bilirubin

1. Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The K(m) values for serum-bound bilirubin were 1.8x10(-3)m and 2.2x10(-3)m respectively for human skin epithelium and human skin; corresponding K(m) values for free bilirubin were 3.0x10(-4)m and 5x10(-4)m. The V(max.) for bound and free bilirubin was of the same magnitude, the apparent V(max.) being 1.0 and 1.66mumol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [(3)H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [(3)H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin.     

Flagellin delivery by Pseudomonas aeruginosa rhamnolipids induces the antimicrobial protein psoriasin in human skin

The opportunistic pathogen Pseudomonas aeruginosa can cause severe infections in patients suffering from disruption or disorder of the skin barrier as in burns, chronic wounds, and after surgery. On healthy skin P. aeruginosa causes rarely infections. To gain insight into the interaction of the ubiquitous bacterium P. aeruginosa and healthy human skin, the induction of the antimicrobial protein psoriasin by P. aeruginosa grown on an ex vivo skin model was analyzed. We show that presence of the P. aeruginosa derived biosurfactant rhamnolipid was indispensable for flagellin-induced psoriasin expression in human skin, contrary to in vitro conditions. The importance of the bacterial virulence factor flagellin as the major inducing factor of psoriasin expression in skin was demonstrated by use of a flagellin-deficient mutant. Rhamnolipid mediated shuttle across the outer skin barrier was not restricted to flagellin since rhamnolipids enable psoriasin expression by the cytokines IL-17 and IL-22 after topical application on human skin. Rhamnolipid production was detected for several clinical strains and the formation of vesicles was observed under skin physiological conditions. In conclusion we demonstrate herein that rhamnolipids enable the induction of the antimicrobial protein psoriasin by flagellin in human skin without direct contact of bacteria and responding cells. Hereby, human skin might control the microflora to prevent colonization of unwanted microbes in the earliest steps before potential pathogens can develop strategies to subvert the immune response.