Stem Cell-Associated Marker Expression in Canine Hair Follicles

Functional hair follicle (HF) stem cells (SCs) are crucial to maintain the constant recurring growth of hair. In mice and humans, SC subpopulations with different biomarker expression profiles have been identified in discrete anatomic compartments of the HF. The rare studies investigating canine HF SCs have shown similarities in biomarker expression profiles to that of mouse and human SCs. The aim of our study was to broaden the current repertoire of SC-associated markers and their expression patterns in the dog. We combined analyses on the expression levels of CD34, K15, Sox9, CD200, Nestin, LGR5 and LGR6 in canine skin using RT-qPCR, the corresponding proteins in dog skin lysates, and their expression patterns in canine HFs using immunohistochemistry. Using validated antibodies, we were able to define the location of CD34, Sox9, Keratin15, LGR5 and Nestin in canine HFs and confirm that all tested biomarkers are expressed in canine skin. Our results show similarities between the expression profile of canine, human and mouse HF SC markers. This repertoire of biomarkers will allow us to conduct functional studies and investigate alterations in the canine SC compartment of different diseases, like alopecia or skin cancer with the possibility to extend relevant findings to human patients.     

STX17在不同毛色小鼠皮肤中差异表达与在毛囊中的定位

突触融合蛋白17 (STX17)是一种囊泡蛋白,参与细胞中物质的运输.为研究Stx17在不同毛色皮肤中是否存在差异表达及明确它在毛囊中的定位,进行了普通PCR、real-time PCR、免疫组化和蛋白免疫印迹实验对小鼠皮肤组织和体外培养黑素细胞的Stx17基因及蛋白的检测.普通PCR检测得出小鼠皮肤和黑色素细胞总RNA有Stx17 CDS区序列的表达;荧光定量检测显示,在白、灰、黑3种组织中Stx17均有表达,在灰色腹部表达量最高,是黑色皮肤的1.682倍,昆明鼠白色皮肤中表达量最低,是黑色皮肤的0.115倍;皮肤组织免疫组化结果显示,STX17表达于毛囊的上皮根鞘,且毛囊上段和中段表达量高于下段,黑色素细胞的免疫组化分析得出,STX17在黑色素细胞的细胞质和细胞膜上均有表达;蛋白免疫印迹结果显示,在白色、灰色和黑色皮肤均有STX17蛋白阳性条带且灰色皮肤中表达量最高,黑色皮肤次之,白色皮肤中表达量是最低的,这与荧光定量检测结果一致,体外培养的小鼠黑色素细胞中也有STX17蛋白阳性条带.实验结果表明,小鼠Stx17基因在皮肤组织、毛囊角化细胞以及黑色素细胞中均有表达,Stx17可能参与毛色的形成,且在小鼠腹部毛色变浅中起到了一定的作用.     

Foot forces during exercise on the International Space Station

Long-duration exposure to microgravity has been shown to have detrimental effects on the human musculoskeletal system. To date, exercise countermeasures have been the primary approach to maintain bone and muscle mass and they have not been successful. Up until 2008, the three exercise countermeasure devices available on the International Space Station (ISS) were the treadmill with vibration isolation and stabilization (TVIS), the cycle ergometer with vibration isolation and stabilization (CEVIS), and the interim resistance exercise device (iRED). This article examines the available envelope of mechanical loads to the lower extremity that these exercise devices can generate based on direct in-shoe force measurements performed on the ISS. Four male crewmembers who flew on long-duration ISS missions participated in this study. In-shoe forces were recorded during activities designed to elicit maximum loads from the various exercise devices. Data from typical exercise sessions on Earth and on-orbit were also available for comparison. Maximum on-orbit single-leg loads from TVIS were 1.77 body weight (BW) while running at 8 mph. The largest single-leg forces during resistance exercise were 0.72 BW during single-leg heel raises and 0.68 BW during double-leg squats. Forces during CEVIS exercise were small, approaching only 0.19 BW at 210 W and 95 RPM. We conclude that the three exercise devices studied were not able to elicit loads comparable to exercise on Earth, with the exception of CEVIS at its maximal setting. The decrements were, on average, 77% for walking, 75% for running, and 65% for squats when each device was at its maximum setting. Future developments must include an improved harness to apply higher gravity replacement loads during locomotor exercise and the provision of greater resistance exercise capability. The present data set provides a benchmark that will enable future researchers to judge whether or not the new generation of exercise countermeasures recently added to the ISS will address the need for greater loading.     

Immunofluorescent Identification of Melanocytes in Murine Hair Follicles

Summary Immunocytochemical identification of skin cells are difficult due to numerous endogenous autofluorescent components within the cell and the environment. This is particularly evident in hair follicles. This paper reports on a serendipitous modification to an existing method which results in a drastically reduced background fluorescence. Immediately after antigen retrieval, sections exposed to 0.3% hydrogen peroxide in methanol for 30 min at room temperature exhibited low background fluorescence, increased antigenicity and revealed quantifiable numbers of melanocytes. This method is applicable to both human and mouse melanocytes particularly in the hair follicle.     

Development and Improvement of Countermeasures against Negative Effects of Weightlessness in Long-Term Space Flights on Board International Space Station

Human Physiology - The paper describes the history of development and improvement of the means of the Russian system of countermeasures against the negative effects of space flights over the past...     

The microgravity environment for experiments on the International Space Station

Experiments are sent to space laboratories in order to take advantage of the low-gravity environment. However, it is crucial to appreciate the distinction between the real microgravity environment and "weightlessness" or "simulated microgravity". The microgravity in space laboratories may be of much smaller magnitude than the gravitational acceleration on earth. However, it is not zero, nor even one microg (defined as 1e-6 earth gravity). Moreover, the orientation is not uniaxial, as on earth. The net acceleration that acts on a space experiment arises from, e.g., orbital mechanics, atmospheric drag, and thruster firings, and it can act on the experiments in gravity-like ways. In essence, a well-defined, stable 1 g acceleration on the earth's surface is substituted for a complex array of dynamically changing accelerations with ever-changing frequency content, magnitude and direction. This paper will show measured accelerations on the Shuttle from launch to orbit, as well as the latest measurements on the International Space Station (ISS). The ISS data presented here represent over 34,790 hours of data obtained from June 2002 to April 2003 during Increments 5 and 6 of the ISS construction cycle. The quasisteady acceleration level on the ISS has been measured to be on the order of a few microg during time allotted to microgravity mode. The vibratory acceleration environment spans a rich spectrum from 0.01-300 Hz.     

Microbial antibiotic production aboard the International Space Station

Previous studies examining metabolic characteristics of bacterial cultures have mostly suggested that reduced gravity is advantageous for microbial growth. As a consequence, the question of whether space flight would similarly enhance secondary metabolite production was raised. Results from three prior space shuttle experiments indicated that antibiotic production was stimulated in space for two different microbial systems, albeit under suboptimal growth conditions. The goal of this latest experiment was to determine whether the enhanced productivity would also occur with better growth conditions and over longer durations of weightlessness. Microbial antibiotic production was examined onboard the International Space Station during the 72-day 8A increment. Findings of increased productivity of actinomycin D by Streptomyces plicatus in space corroborated with previous findings for the early sample points (days 8 and 12); however, the flight production levels were lower than the matched ground control samples for the remainder of the mission. The overall goal of this research program is to elucidate the specific mechanisms responsible for the initial stimulation of productivity in space and translate this knowledge into methods for improving efficiency of commercial production facilities on Earth.     

Wnt通路中的部分基因在绒山羊胚胎皮肤毛囊中的表达分析

已知绒山羊毛囊的发育受Wnt等信号通路控制,但Wnt通路相关基因在绒山羊胚胎毛囊启动和生长发育过程中的表达及作用机制尚不清楚。本文采用RNA-Seq技术对45 d,55 d和65 d的绒山羊胚胎体侧皮肤进行了转录组测序,鉴定Wnt通路相关基因的表达。 RNA- Seq技术结合blast搜索,将转录组有效测序数据与云南黑山羊参考基因组序列(http://goat. kiz.ac. cn/GGD/download.htm)比对,获得了已知的Wnt通路（pathway hsa04310）中的123个相关基因（86.0%）。进而采用实时荧光定量PCR技术检测,验证了差异表达的Sfrp4、Wnt3、Wnt10a（上调）和Apc2（下调）基因在绒山羊胚胎不同时期皮肤中的表达量,初步探索了绒山羊毛囊在胚胎期启动、发育过程中,Wnt通路部分基因的表达模式,为进一步研究Wnt通路部分基因在绒山羊胚胎毛囊启动、发育过程中的作用机制提供了有意义的线索。     

The development of the International Space Station centrifuge.

Gravitational biology research facility "Centrifuge" is currently under development for the International Space Station. Research in the Complex Organism Biology, indispensable to the progress in Health Science, is only possible in the Centrifuge aboard the station. So, on-orbit 1 G controls for various specimens including small mammals, fish, and higher plants will be rigorously done in the Centrifuge. This facility is also capable of providing "reduced gravity" likely on the Moon or on Mars. Thus, it will play a key role in creating knowledge of space fundamental biology. As part of the offset of NASA's Shuttle launch services for the Japanese Experiment Module, JAXA is developing the Centrifuge Rotor (CR), the Life Sciences Glovebox (LSG) and the Centrifuge Accommodation Module (CAM). Critical Design Review (CDR) of LSG was conducted on July 2004, while the system CDRs of the CAM and CR are scheduled for December 2004 and August 2005, respectively. Their launch schedules are under review.     

小鼠皮肤及其毛囊早期发育的组织学观察

目的探讨小鼠皮肤及其毛囊的早期发育规律。方法采用常规石蜡切片和H-E染色技术,观察昆明系小鼠出生前后皮肤及其毛囊的形态发育。结果(1)孕龄16 d胎鼠的皮肤表面形成凹凸不平的深褶皱,但在生后3 d~5 d不仅皱褶的数量减少,而且凹陷变浅;(2)胎鼠孕龄16 d至19 d,其皮肤的表皮、真皮及皮肤总厚度呈现平稳增厚。但是,出生后,其表皮、真皮和皮肤总厚度急剧降低;在生后第1天至第9天,表皮呈现平稳增厚,而真皮则在生后快速厚度,第7天达到最高值(1861.50μm);(3)孕龄16 d的胎鼠皮肤中可观察到初级毛囊,至生后第7天其密度呈现平稳增长;与其相比,次级毛囊从18 d胎鼠开始出现,其密度增长非常迅速,出生后第7天达到1257.14/mm;毛囊的总密度与次级毛囊呈现相似的变化趋势。出生第7天后,由于毛囊的数量急剧增加,无法观察初级毛囊和次级毛囊的变化规律;(4)初级毛囊和次级毛囊的长度与深度变化在出生前后的相对缓慢,与其相比在第3天以后至第7天呈现迅速变化趋势。结论小鼠皮肤及其毛囊的生长性发育发生在胎儿晚期和生后的早期,而其周期性变化可能从出生后的第9天以后开始出现;在孕期16 d至生后第7天可能是检测毛囊特异性基因表达的最佳期。     

Heavy-ion anisotropy measured by ALTEA in the International Space Station

The uneven shielding of the International Space Station from the vessel hull, racks and experiments produces a modulation of the internal radiation environment. A detailed knowledge of this environment, and therefore of the Station's shielding effectiveness, is mandatory for an accurate assessment of radiation risk. We present here the first 3D measurements of the Station's radiation environment, discriminating particle trajectories and LET, made possible using the detection capability of the ALTEA-space detector. We provide evidence for a strong (factor ≈ 3) anisotropy in the inner integral LET for high-LET particles (LET > 50?keV/μm) showing a minimum along the longitudinal station axis (most shielded) and a maximum normal to it. Integrating over all measured LETs, the anisotropy is strongly reduced, showing that unstopped light ions plus the fragments produced by heavier ions approximately maintain flux/LET isotropy. This suggests that, while changing the quality of radiation, the extra shielding along the station main axis is not producing a benefit in terms of total LET. These features should be taken into account (1) when measuring radiation with detectors that cannot distinguish the direction of the impinging radiation or that are unidirectional, (2) when planning radiation biology experiments on the ISS, and (3) when simulating the space radiation environment for experiments on the ground. A novel analysis technique that fully exploits the ability to retrieve the angular distribution of the radiation is also presented as well as the angular particle flux and LET characteristic of three geomagnetic zones measured during 2009 by the ALTEA-space detector. This technique is applied to the ALTEA-space detector, but a wider applicability to other detectors is suggested.     

A Method for Determining the Activity State of Hair Follicles

A histological method is described for determining the proportion of growing hair follicles h skin samples. A variation of the Sacpic staining method, modified for bulk processing, produces high contrast staining of the principal tissue types present in skin. In particular, the inner root sheath is accentuated, facilitating detection of active follicles. Skin preparations from a range of species are used to illustrate structural characteristics of follicles viewed in cross section at various stages of the hair cycle and to establish criteria for classification of the state of activity of follicles. The hair cycle may be divided into quiescent and active states at the points of rapid transition (early pronanagen and mid catagen). Data from repeated skin biopsies from ferrets and goats are also used to demonstrate quantitative estimation of follicle activity, change in compound follicle size, and the relationship between follicle type and fiber medullation.     

Investigations of a simulated geomagnetic field experienced by the International Space Station on attentional performance

We have previously reported that the exposure to an abnormal magnetic field simulating the one encountered by the International Space Station (ISS) orbiting around the Earth may enhance autonomic response to emotional stimuli. Here we report the results of the second part of that study which tested whether this field also affects cognitive functions. Twenty-four volunteers participated in the study, 12 exposed to the natural geomagnetic field and 12 to the magnetic field encountered by ISS. The test protocol consisted of a set of eight tests chosen from a computerized test battery for the assessment of attentional performance. The duration of exposure was 90 min. No effect of exposure to ISS magnetic field was observed on attentional performance.     

Characterization of fungi isolated from the equipment used in the International Space Station or Space Shuttle

As a part of a series of studies regarding the microbial biota in manned space environments, fungi were isolated from six pieces of equipment recovered from the Japanese Experimental Module “KIBO” of the International Space Station and from a space shuttle. Thirty‐seven strains of fungi were isolated, identified and investigated with regard to morphological phenotypes and antifungal susceptibilities. The variety of fungi isolated in this study was similar to that of several previous reports. The dominant species belonged to the genera Penicillium, Aspergillus and Cladosporium, which are potential causative agents of allergy and opportunistic infections. The morphological phenotypes and antifungal susceptibilities of the strains isolated from space environments were not significantly different from those of reference strains on Earth.     

Shuttle radiation dose measurements in the International Space Station orbits.

The International Space Station (ISS) is now a reality with the start of a permanent human presence on board. Radiation presents a serious risk to the health and safety of the astronauts, and there is a clear requirement for estimating their exposures prior to and after flights. Predictions of the dose rate at times other than solar minimum or solar maximum have not been possible, because there has been no method to calculate the trapped-particle spectrum at intermediate times. Over the last few years, a tissue-equivalent proportional counter (TEPC) has been flown at a fixed mid-deck location on board the Space Shuttle in 51.65 degrees inclination flights. These flights have provided data that cover the expected changes in the dose rates due to changes in altitude and changes in solar activity from the solar minimum to the solar maximum of the current 23rd solar cycle. Based on these data, a simple function of the solar deceleration potential has been derived that can be used to predict the galactic cosmic radiation (GCR) dose rates to within +/-10%. For altitudes to be covered by the ISS, the dose rate due to the trapped particles is found to be a power-law function, rho(-2/3), of the atmospheric density, rho. This relationship can be used to predict trapped dose rates inside these spacecraft to +/-10% throughout the solar cycle. Thus, given the shielding distribution for a location inside the Space Shuttle or inside an ISS module, this approach can be used to predict the combined GCR + trapped dose rate to better than +/-15% for quiet solar conditions.