A review of ageing and an examination of clinical methods in the assessment of ageing skin. Part I: Cellular and molecular perspectives of skin ageing

The ageing process is noticeable within all organs of the body and manifests itself visibly in the skin. Skin ageing is influenced by several factors including genetics, environmental exposure, hormonal changes and metabolic processes. Together these factors lead to cumulative alterations of skin structure, function and appearance. The functioning of the central nervous, immune, endocrine and cardiovascular systems, as well as the skin is also impaired with age. Chronologically, aged skin is thin, relatively flattened, dry and unblemished, with some loss of elasticity and age-related loss of architectural regularity. General atrophy of the extracellular matrix is reflected by a decrease in the number of fibroblasts. Reduced levels of collagen and elastin, with impaired organization are primarily because of decreased protein synthesis affecting types I and III collagen in the dermis, with an increased breakdown of extracellular matrix proteins. Oxidative stress is considered of primary importance in driving the ageing process. The original free radical theory of ageing purported that the molecular basis of ageing was derived from a lifetime accumulation of oxidative damage to cells resulting from excess reactive oxygen species (ROS) produced as a consequence of aerobic metabolism. Although the skin possesses extremely efficient anti-oxidant activities, during ageing, ROS levels rise and anti-oxidant activities decline. The ROS are necessary in multiple MAP kinase pathways and the induction of AP-1, in turn, up-regulates expression of matrix-metalloproteinases providing a plausible mechanism for the increased collagen degradation in aged human skin.     

不同胁迫因子对葡萄皮中白藜芦醇含量的影响

为了提高葡萄皮的综合利用价值,探讨pH、过氧化氢、氯化铝等六个化学因素对葡萄皮中白藜芦醇含量的影响。分别在pH、过氧化氢、氯化铝等七个因素影响下探讨白藜芦醇的含量变化。结果表明,在pH为13、过氧化氢浓度为5%、氯化铝浓度为90μg/mL、硝酸银浓度为10μg/mL、紫外照射254 nm、热休克的影响下,葡萄皮中白藜芦醇含量是增加的;而在低温(-20℃)的影响下,白藜芦醇的含量是降低的。通过分析影响葡萄皮中白藜芦醇含量的变化的原因,提高了白藜芦醇的提取率,更好地提高葡萄皮的综合利用率。     

Stress responses during milking; comparing conventional and automatic milking in primiparous dairy cows

A comparative study was performed to evaluate the differences in behavioral and physiological stress responses during milking between cows that were milked by an automated milking system (AM-cows) and cows that were milked in a conventional tandem parlor (TM-cows). In a randomized design, 36 primiparous Holstein-Friesian dairy cows were observed and blood sampled (1-min intervals) individually during milking. AM-cows spent less time standing with their heads outside the feeding trough than TM-cows and had a lower heart rate. In addition, AM-cows had lower maximum plasma adrenaline and noradrenaline concentrations during milking. No differences were found in the number of steps. After tactile stimulation of the teats either by hand or by the cleaning brush, mean oxytocin concentrations did not differ. In AM-cows, however, elevated oxytocin levels were prolonged at the end of milking. Averaged over the first five blood samples, AM-cows tended to have higher plasma cortisol concentrations than TM-cows, but median fecal concentrations of the cortisol metabolite dioxoandrostane were comparable. Maximum quarter milk flow, maximum udder milk flow and residual milk as a percentage of the total milk volume was comparable. From this study it is concluded that behavioral and physiological responses, both in automatically and in conventionally milked cows, were relatively low and were typical for cows being milked. We therefore conclude that, as far as the welfare of the dairy cow during milking is concerned, automatic milking and conventional milking are equally acceptable.     

Quantification of the skin's topography by skin profilometry

A method of skin profilometry is presented. The data generated using this method are used to (a) uncover sources of variation in skin profilometry, (b) provide information regarding the choice of roughness parameters best suited for characterizing the skin's topography, and (c) determine if skin profilometry is a valuable tool for quantitatively assessing changes in the skin's surface pattern.
The data show the roughness parameter values to be dependent on the orientation of the tracings with regard to the major grooves and ridges present in the surface patterns. Large variabilities of roughness parameter values obtained for multiple scans within small areas of replicas are indicative of the nonhomogeneity of the skin's surface. The number of peaks, mean peak size, mean depth of roughness, depth of smoothness, and residual profile length appear to be the most utile roughness parameters for quantifying changes in the skin's topography. The ability of skin profilometry to detect subtle changes in the skin's surface pattern due to hydration indicates the method is a sensitive means of quantifying the skin's topography.
Quantification de la topographie de la pedu par la profilométrie de la pedu     

银狐皮毛被及皮板组织构造的研究(续)

用光学显微镜和扫描电镜观察了国产人工饲养银狐的毛被和皮板组织构造 ,测定了毛的长度、细度、密度、毛的鳞片高度和皮板厚度。提供了毛和皮板组织学图片 15幅     

Sex- and site-dependent variations in the thickness and mechanical properties of human skin in vivo

A new method for the in vivo characterization of the physical properties of skin is presented. This comprises an ultrasound device to measure the vertical displacement of the surface of the skin, as well as its thickness and that of the hypodermis under suction. In combination with this, a mathematical model is used to calculate the following skin parameters: Young's modulus, the initial stress and an index of non-elasticity. These parameters were evaluated from the volar forearm and the forehead of 30 male and 30 females, of similar ages (28 +/- 6-years-old). The sensitivity of the testing procedure, allowing the characterization of the mechanical parameters of the skin, easily differentiated these two sites, and in some cases, differences between women and men were demonstrated. The main results showed for both sexes that the thickness (P = 0.0001), Young's modulus (P = 0.0001), and the index of non-elasticity (P = 0.0001) were greater for the forehead than for the ventral forearm, but that the initial stress was lower (P = 0.0001). The results show that the skin is thicker, stiffer and less tense and elastic on the forehead than on the ventral forearm, suggesting structural differences between these two sites (collagen fibre network, elastic fibres, epidermis, stratum corneum, microvascularization, actinic damage, presence of sebaceous glands, etc.). It is hoped that this device will be useful for the evaluation of certain skin disorders (scleroderma, Ehlers-Danlos syndrome, cutis laxa, oedema, etc.) and their therapy, as well as being a useful tool in skin ageing and cosmetic product assessment.     

Influence of skin cleansing preparation acidity on skin surface properties

Two long-term trials were conducted each over eight weeks to compare the effect of the regular application of skin cleansing preparations of pH 5.5 and pH 8.5 and pH 5.5 and pH 7.0 respectively on the surface pH, roughness and transepidermal water loss (TEWL) of normal human forehead and forearm skin. Both trials were based on a cross-over design: five healthy volunteers started with a pH 5.5 preparation and switched to the other after four weeks, five additional volunteers used the preparations in the opposite order. While the skin surface pH was markedly lower in those individuals using the pH 5.5 preparation at each examination, as compared to those using the pH 8.5 or pH 7.0 preparation, no such difference could be established with respect to skin roughness and TEWL. Hence the skin irritancy of a cleansing preparation does not seem to be linked to its pH within the pH ranges tested.     

银狐皮毛被及皮板组织构造的研究

用光学显微镜和扫描电镜观察了国产人工饲养银狐的毛被和皮板组织构造 ,测定了毛的长度、细度、密度、毛的鳞片高度和皮板厚度。提供了毛和皮板组织学图片 15幅。     

鲨鱼皮胶原与罗非鱼皮胶原的理化性质及酶解特性研究

为了系统比较深海鱼和淡水鱼胶原的差异,利用酸法提取鲨鱼皮胶原和罗非鱼皮胶原,并对它们的理化性质和酶解特性进行了考察。氨基酸组成分析表明,鲨鱼皮胶原中异亮氨酸含量大约是罗非鱼皮胶原的2倍,但脯氨酸含量较少。鲨鱼皮胶原α肽链和β肽链的分子量,以及胶原热变性温度都低于罗非鱼皮胶原,但在紫外光谱和红外光谱中没有发现明显的差异。另一方面,电泳图谱和液相图谱都表明,鲨鱼皮胶原和罗非鱼皮胶原容易被胶原酶和胰蛋白酶酶解,不易被木瓜蛋白酶酶解。在胶原酶与底物质量比为0.05%,pH8.0和50℃的酶解条件下,经过240min酶解,鲨鱼皮胶原肽中小于1000u的肽含量达到23%,而罗非鱼胶原肽中却只有17%。      

A review of ageing and an examination of clinical methods in the assessment of ageing skin. Part 2: Clinical perspectives and clinical methods in the evaluation of ageing skin

With the advancement of skin research, today's consumer has increased access to technological information about ageing skin and hair care products. As a result, there is a rapidly increasing demand for proof of efficacy of these products. Recognizing these demands has led to the development and validation of many clinical methods to measure and quantify ageing skin and the effects of anti-ageing treatments. Many of the current testing methods used to research and evaluate anti-ageing product claim to employ sophisticated instruments alongside more traditional clinical methods. Intelligent use of combined clinical methods has enabled the development of technologically advanced consumer products providing enhanced efficacy and performance. Of non-invasive methods for the assessment and quantification of ageing skin, there is a plethora of tools available to the clinical researcher as defined by key clinically observed ageing parameters: skin roughness and surface texture; fine lines and wrinkles; skin pigmentation; skin colour; firmness and elasticity; hair loss; and proliferative lesions. Furthermore, many clinical procedures for the evaluation of ageing skin treatments are combined with invasive procedures, which enable added-value to claims (such as identification and alteration of biochemical markers), particularly in those cases where perception of product effect needs additional support. As discussed herein, clinical methods used in the assessment of skin ageing are many and require a disciplined approach to their use in such investigations.     

Intrinsic and extrinsic factors in skin ageing: a review

As the proportion of the ageing population in industrialized countries continues to increase, the dermatological concerns of the aged grow in medical importance. Intrinsic structural changes occur as a natural consequence of ageing and are genetically determined. The rate of ageing is significantly different among different populations, as well as among different anatomical sites even within a single individual. The intrinsic rate of skin ageing in any individual can also be dramatically influenced by personal and environmental factors, particularly the amount of exposure to ultraviolet light. Photodamage, which considerably accelerates the visible ageing of skin, also greatly increases the risk of cutaneous neoplasms. As the population ages, dermatological focus must shift from ameliorating the cosmetic consequences of skin ageing to decreasing the genuine morbidity associated with problems of the ageing skin. A better understanding of both the intrinsic and extrinsic influences on the ageing of the skin, as well as distinguishing the retractable aspects of cutaneous ageing (primarily hormonal and lifestyle influences) from the irretractable (primarily intrinsic ageing), is crucial to this endeavour.     

外源抗氧化剂对高温胁迫下红地球葡萄果皮组织CAT、APX和SOD酶活性的影响

以红地球葡萄为试材,喷施抗坏血酸(Vc)、苯甲酸钠(SBN)、水杨酸(SA)、柠檬酸(CA)、氯化钙(CaCl2)等5种抗氧化剂,研究不同外源抗氧化剂对高温胁迫下果皮组织中过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、超氧化物歧化酶(SOD)活性的影响。结果表明:喷施外源抗氧化剂均能显著提高果皮组织内CAT、APX和SOD的活性。综合分析:以Vc 10 mmol/L,SA 0.05 mmol/L,CA 10 mmol/L,Vc 10 mmol/L+CaCl21000 mg/L,Vc 10 mmol+SBN 10 mmol/L为极显著。     

The effect of smoking on skin moisture and on surface lipids

In the present retrospective study we investigated the effect of smoking on the moisture and surface lipid levels of the skin. We analysed data from the files of 576 female clients treated in a Tel-Aviv cosmetic parlour. Measurements have been conducted by the same cosmetician, by commercially available equipment, on every client receiving cosmetic treatment, regardless of the nature of the treatment.
Results demonstrated a significant difference of skin moisture in the various smoking groups: women who smoked 11–20 cigarettes per day showed significantly lower mean values than the non-smoker group, as expected. Moreover, women before or after menopause showed no significant differences in their moisture measurements.
The surface lipid variables showed no significant differences in mean over the four smoking groups.
We believe that the objective of the study was achieved, and that the results, indicating decreased skin moisture in smokers, will serve well in anti-smoking campaigns. We also believe that the present study will stimulate other investigators to conduct similar studies that will provide answers to the many questions which still remain open.