Immunolocalization of a mammalian aquaporin 3 homolog in water-transporting epithelial cells in several organs of the clawed toad Xenopus laevis

Nucleotide sequences of cDNA were used to construct antibodies against an aquaporin (AQP) expressed in the clawed toad, Xenopus laevis, viz., Xenopus AQP3, a homolog of mammalian AQP3. Xenopus AQP3 was immunolocalized in the basolateral membrane of the principal cells of the ventral skin, the urinary bladder, the collecting duct and late distal tubule of the kidney, the absorptive epithelial cells of the large intestine, and the ciliated epithelial cells of the oviducts. Therefore, we designated this AQP as basolateral Xenopus AQP3 (AQP-x3BL). The intensity of labeling for AQP-x3BL differed between the ventral and dorsal skin, with the basolateral membrane of the principal cells in the ventral skin showing intense labeling, whereas that in the dorsal skin was lightly labeled. AQP-x3BL was also immunolocalized in the basolateral membrane of secretory cells in the small granular and mucous glands of the skin. As AQP-x5, a homolog of mammalian AQP5, is localized in the apical membrane of these same cells, this provides a pathway for fluid secretion by the glands. Although Hyla AQP-h2 is translocated from the cytoplasm to the apical membrane of the Hyla urinary bladder in response to arginine vasotocin (AVT), AQP-h2 immunoreactivity in Xenopus bladder remains in the cytoplasm and barely moves to the apical membrane, regardless of AVT stimulation. AQP-x3 is localized in the basolateral membrane, even though the AVT-stimulated AQP-h2 does not translocate to the apical membrane. These findings provide new insights into AQP function in aquatic anurans.     

Quality and flavour stability of coffee substitute prepared by extrusion of wheat germ and chicory roots

Summary. A mixture of roasted chicory roots and wheat germ (1:1 w/w) was subjected to extrusion processing for preparation of coffee substitute. Comparative studies concerning sensory characteristics and headspace volatiles were carried out between genuine coffee and a freshly prepared coffee substitute. The sensory evaluation revealed similarities between the two samples. The comparative odour profile analysis showed that the sweetish/caramel-like note scored higher in our coffee substitute sample than in real coffee, whereas the other odour quality attributes showed an opposite trend. The high quality of the fresh coffee substitute was correlated to the presence of volatiles that are responsible for the fresh coffee aroma, such as: 2-methylbutanal, 3-methylbutanal, 2-methylfuran and 2,3-butanedione in high concentration. Storage of coffee substitute samples revealed a noticeable decrease in concentration of the Strecker aldehydes and diketones and a remarkable increase in phenolic compounds, whereas pyrazine and furan derivatives showed no linear changes during storage. The ratio of 2,3-butanedione/2-methylfuran (B/M) was used as an indicator for aging of coffee substitute samples. The variation in this ratio (B/M) during storage for 6 months was consistent with that of the odour profile analysis. Authors’ address: Prof. Dr. Hoda H. M. Fadel, Chemistry of Flavour and Aroma Department, National Research Centre, Al-Behos St., Dokki, Cairo, Egypt     

Skin thermal pain modeling—A holistic method

Pain sensation has been studied extensively, over a range of scales, from the molecular level to the entire human neural system. Thermal stimulation of pain has been widely used in the study of pain sensation. Skin thermal pain is induced through both direct (an increase/decrease in temperature) and indirect (thermomechanical and thermochemical) ways, and is governed by complicated thermomechanical–chemical–neurophysiologic responses. This paper is focused on the theoretical modeling of the underlying mechanisms in the process of skin thermal pain. A holistic model has been developed, which is composed of three sub-models, namely, transduction, transmission, and modulation and perception. The model can contribute to the understanding of thermally related pain phenomena in skin tissue and to improvements in a range of thermal therapeutic methods.     

Modelling the stratum corneum lipid organisation with synthetic lipid mixtures: the importance of synthetic ceramide composition

Cholesterol (CHOL), free fatty acids (FFA) and nine classes of ceramides (CER1-CER9) form the main constituents of the intercellular lipid lamellae in stratum corneum (SC), which regulate the skin barrier function. Both the presence of a unique 13-nm lamellar phase, of which the formation depends on the presence of CER1, and its dense lateral packing are characteristic for the SC lipid organisation. The present study focuses on the lipid organisation in mixtures prepared with CHOL, FFA and a limited number of synthetic CER, namely CER1, CER3 and bovine brain CER type IV (∑CERIV). The main objective is to determine the optimal molar ratio of CER3 to ∑CERIV for the formation of the 13-nm lamellar phase. CER3 contains a uniform acyl chain length, whereas ∑CERIV contains fatty acids with varying chain lengths. Using small angle X-ray diffraction (SAXD), it is demonstrated that the CER3 to ∑CERIV ratio affects the formation of the 13-nm lamellar phase and that the optimal ratio depends on the presence of FFA. Furthermore, the formation of the 13-nm lamellar phase is not very sensitive to variations in the total CER level, which is similar to the in vivo situation.     

物质经皮转运的唯象理论

物质经皮渗透是一个非平衡态的热力学过程,驱使物质经皮转运的动力产生了物质经皮转运的通量,文章试图用唯象理论来阐述这种关系。假设扩散池系统恒温、无化学反应：溶液为非粘性流体,双组份、局域平衡。根据Gibbs方程,建立了扩散池系统的耗散函数,导出了其质量流与质量力、体积流与体积力：实验分对照组(被动扩散)和实验组(电脉冲扩散),分别做3次并以替硝唑为模式药物。实验结果表明：(1)扩散池系统中不但存在物质的经皮渗透,而且存在溶液的体积缺失现象;(2)根据实验数据,确定唯象系数具有时变性,并且推断当时间延迟时,质量力对质量流和体积力对体积流的影响减弱;(3)溶液对流在皮肤表面产生的速度梯度可能产生体积流。结论是扩散池药物经皮渗透系统是一个非线性时变系统。     

The Expression and Activation of Protease‐Activated Receptor‐2 Correlate with Skin Color

Skin color results from the production and distribution of melanin in the epidermis. The protease‐activated receptor‐2 (PAR‐2), expressed on keratinocytes but not on melanocytes, is involved in melanosome uptake via phagocytosis, and modulation of PAR‐2 activation affects skin color. The pattern of melanosome distribution within the epidermis is skin color‐dependent. In vitro, this distribution pattern is regulated by the ethnic origin of the keratinocytes, not the melanocytes. Therefore, we hypothesized that PAR‐2 may play a role in the modulation of pigmentation in a skin type‐dependent manner. We examined the expression of PAR‐2 and its activator, trypsin, in human skins with different pigmentary levels. Here we show that PAR‐2 and trypsin are expressed in higher levels, and are differentially localized in highly pigmented, relative to lightly pigmented skins. Moreover, highly pigmented skins exhibit an increase in PAR‐2‐specific protease cleavage ability. Microsphere phagocytosis was more efficient in keratinocytes from highly pigmented skins, and PAR‐2 induced phagocytosis resulted in more efficient microsphere ingestion and more compacted microsphere organization in dark skin‐derived keratinocytes. These results demonstrate that PAR‐2 expression and activity correlate with skin color, suggesting the involvement of PAR‐2 in ethnic skin color phenotypes.     

Sleep propensity is modulated by circadian and behavior-induced changes in cutaneous temperature

A close relation between sleep and body temperature has been noted already for a long time. Although a correlation is indisputable, there is at present hardly evidence for a causal involvement of sleep in changes in body temperature. Concerning the reverse, a causal involvement of body temperature in sleep has been demonstrated: if core or skin temperature changes activate thermoregulatory processes aimed at heat loss or heat preservation, sleep is usually disrupted. We have recently proposed that sleep propensity is also affected by more subtle changes in skin temperature, within the thermoneutral range (Van Someren (2000). Chronobiol. Int. 17, 313–354). These changes are likely to modulate the firing properties of thermosensitive neurons in brain areas involved in sleep regulation. Subtle changes in skin temperature occur daily under control of the circadian timing system. They could provide this system with an additional signal pathway to support its neuronal and neurohormonal signals to enforce circadian modulation of sleep propensity. Subtle changes in skin temperature also result from behavior, and could contribute to the changes in sleep propensity resulting from these behaviors. The present review summarizes the neurobiological background and correlational physiological and behavioral data in support of the involvement of skin temperature in the modulation of sleep propensity. It moreover points out the type of experimental investigations needed to support or refute the hypothesis.     

X射线辐射对仔鼠体重、皮毛生长及肝、肾脏组织SOD、CAT活力及MDA含量的影响

本文采用比色法测定不同剂量（0．0、0．5、2．0、3．5、5．0、6．5Gy）X射线辐射对不同发育期（1、5、10和20d）仔鼠肝脏及肾脏组织超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活力和丙二醛（MDA）含量的影响,探讨X射线辐射后小鼠的体重、皮毛及肝、肾组织抗氧化酶活性的动态变化,为电离辐射防治提供实验依据。结果表明：经2．0、3．5、5．0和6．5GyX射线辐射后的仔鼠体重降低;3．5、5．0和6．5Gy辐射后3d开始脱毛,10d脱毛处开始长出新毛,6．5Gy辐射组鼠脱毛处皮肤出现紫斑;0．5Gy辐射组仔鼠肝脏及肾脏中SOD活性在辐射初期升高,后逐渐降低至近似正常水平,其它各组则先降低,后缓慢升高但始终低于对照组;0．5Gy辐射组仔鼠肝脏及肾脏MDA含量先降低,后升高至近似正常水平,其它各组则先升高,后缓慢降低,始终高于对照组;0．5、2．0Gy辐射组其仔鼠肝脏及肾脏CAT活性在辐射后初期降低,后升高,最终至近似正常水平;其它各组则在初期升高,后降低。辐射后一段时间内检测各组仔鼠肝脏及肾脏中各种酶的活性均有不同程度恢复正常的趋势。表明X射线影响生长发育中仔鼠的体重、皮毛生长及肝、肾组织的抗氧化酶活性,且剂量因素的影响大于时间因素。大剂量电离辐射对发育期仔鼠具有损伤作用[动物学报54（6）：1029-1037,2008]。     

陈旧皮张中DNA提取的新方法

对传统的馆藏陈旧皮张标本DNA提取方法进行了改进,所提DNA分子量可达1kb,而且具有样品用量少（约0.01g),消化时间短（约14h)和操作步骤简单等优点,利用所提DNA,对小熊猫等珍稀动物线粒体DNA的细胞色素b和控制区序列的部分片段进行了PCR扩增,序列测定和比较分析,证实所提DNA合格而无污染,完全可以用于珍稀动物保护遗传学研究。     

Depigmenting Action of Phenylhydroquinone,an o‐Phenylphenol Metabolite,on the Skin of JY‐4 Black Guinea‐Pigs

The effects of o‐phenylphenol (OPP) and its metabolite, phenylhydroquinone (PHQ) on the skin of JY‐4 black guinea‐pigs were studied. Topical application of 1 or 5% PHQ on the black skin of the back caused marked depigmentation and hypopigmentation of the skin after 5 weeks, whereas OPP applied at the same concentrations had little effect. Depigmented skin had an increased L* (lightness) value in the CIE‐L*a*b* color system. This corresponded with a decreased number of melanocytes and melanosomes in the melanocytes and keratinocytes, the disruption of melanosomes in the melanocytes, and destruction of the membranous organelles of the melanocytes. These morphological and numerical changes in epidermal melanocytes indicate that selective melanocyte toxicity occurred. Furthermore, application of PHQ to the skin of white guinea‐pigs caused skin irritation, as shown by a colorimetric increase in a* value (redness) and by histological observation of inflammation. This study confirmed that OPP, which is a reported depigmenter, has little depigmenting action, while its metabolite, PHQ, is a potent depigmenter preferentially affecting melanocytes.