Gap junctions and impulse propagation in embryonic epithelium of Amphibia

Summary Epithelium of amphibian embryos (Cynops orientalis, Xenopus laevis) was found in preceding experiments to generate and conduct impulses during a limited stage (26–37) of development. In order to elucidate the structural basis of impulse propagation, epithelial cells of four stages were examined by the freeze-etching method: (I) before and (II) during acquisition of conductivity; (III) when propagation was fully established, and (IV) when it was no longer present. Only few gap junctions (GJ) of small size were found in groups I and IV. GJ in epithelia of group III were increased in number and size, and appeared morphologically coupled, i.e., with more loosely arranged connexons. The size of gap-junctional particles did not differ significantly between coupled and uncoupled stages. Zonulae occludentes seemed leaky in stage I, and tight in stages II–IV. Thus, the morphological characteristics of specialized junctions between non excitable cells correlated with the opening and closing of low resistance intercellular current pathways during embryonic development.Gap junctions in particular seem to form an essential link in the non-neural stimulus-response system, which may facilitate the mobility of the embryo during early phases of aquatic life before the reflex pathways have been established. Coupling and uncoupling of gap junctions may also play an important role in the regulation of cell differentiation and morphogenetic movement. The experimental model used in this study provides a useful tool for further investigations of structural correlates of gap junctional permeability under physiological conditions.     

Heritability and components of phenotypic expression in skin reflectance of Mestizos from the Peruvian Lowlands

Skin reflectance was measured on the inner upper arm and forehead of a sample of 209 Mestizos ranging in age from 2 to 64 years living in the town of Lamas in the Eastern Peruvian Lowlands. The sample consisted of 43 father-son, 42 father-daughter, 62 mother-son, and 70 mother-daughter pairs. The sample also consisted of 57 brother-brother, 60 sister-sister and 139 brother-sister pairs. The reflectance measurements were made with a Photovolt Reflection Meter, model 670. Stepwise polynomial regression techniques were used to derive standardized residual values. Then using these residual values parent-offspring, sibling intraclass correlations and components of the phenotypic expression of skin reflectance were calculated. The study indicates that 1) the parent-offspring and sibling correlation coefficients conformed with the theoretical correlations expected assuming polygenic inheritance; 2) the husband-wife correlations indicate a high degree of assortative mating for skin color, but despite this effect the parent-offspring and sibling correlation coefficients are lower than the values expected under the influence of autosomal genes; 3) estimates of heritability and components of phenotypic expression indicate that about 55% of the total variability in skin reflectance could be attributed to the influence of additive genetic factors; and 4) there is no evidence of X-linkage in the inheritance of skin color.     

Ixodes dammini: Induced skin lesions in guinea pigs and rabbits compared to erythema chronicum migrans in patients with lyme arthritis

Erythematous skin lesions occurred in rabbits 2 days after being fed upon by larvae or nymphs of the tick, Ixodes dammini. Similar lesions occurred in guinea pigs 7 days after a primary infestation with either larvae or nymphs. Host resistance to secondary feeding by larvae was demonstrated in guinea pigs and rabbits. Host resistance to secondary feeding by nymphs was seen in guinea pigs, but not in rabbits. Guinea pigs developed resistance to nymphs after being previously fed upon twice by larvae. All skin lesions in resistant guinea pigs contained large accumulations of basophils (49–76% of cells) with smaller (20–33%), but significant, numbers of eosinophils. These responses were characteristic of strong cutaneous basophil hypersensitivity reactions. Primary and secondary lesions in rabbits fed upon by larvae contained mostly mononuclear cells (46–52%) and moderate numbers (16–30%) of basophils and eosinophils. Primary and secondary lesions in rabbits fed upon by nymphs had few (3–11%) basophils and eosinophils and were dominated by mononuclear cells (73–86%). Thus, acquired resistance in guinea pigs and rabbits was associated with cutaneous basophil and eosinophil responses and the lack of resistance of rabbits to nymphs was associated with erythematous lesions dominated by mononuclear cells. The mononuclear nature of rabbit lesions induced by nymphal feeding was similar to that seen in erythema chronicum migrans in Lyme arthritis patients who are thought to have been fed upon by I. dammini nymphs. This study confirms the cutaneous basophil hypersensitivity characteristics of lesions in guinea pigs resistant to ticks and demonstrates a relationship between the mononuclear cell response of rabbits to nymphal I. dammini and the cellular response seen in patients with erythema chronicum migrans and Lyme arthritis.     

Schistosoma japonicum: Immediate hypersensitivity reactions to egg antigen in humans and rodents

Immediate hypersensitivity reactions in schistosoma japonicum infections were examined in both man and experimental animals. In man higher reaction to soluble egg antigen than to adult worm antigen was detected by the use of the radioallergosorbent test (RAST). Blood-collecting filter paper can be used in RAST for seroepidemiological study in place of a skin test. Reaginic antibody formation against egg antigen was detected at the approximate time of egg deposition in strains of mice, Mongolian gerbils, cotton rats, and laboratory rats by the use of passive cutaneous anaphylaxis or Prausnitz-Küstner-type skin tests. At the same time circumoval precipitin tests were positive. Results with athymic nude mice suggest that these reactions are T-cell dependent. No detectable reagin synthesis against adult worm antigen was found in the animals so far examined, confirming stronger allergenic reaction to egg antigen than to that of adult worms in S. japonicum infections in man and animals.     

Schistosoma mansoni: Ultrastructure of early transformation of skin- and shear-pressure-derived schistosomules

Against the background of cercarial fine structure, ultrastructural changes were compared in schistosomules of Schistosoma mansoni 30 min and 1 hr after their production in vivo by skin penetration and in vitro by shear pressure. The same developmental pattern was observed in schistosomules of both derivations. In vitro schistosomules, however, developed more slowly, resembled cercariae more closely, and varied less among organisms than did in vivo schistosomules. The greatest morphological changes were observed in the 1-hr in vivo schistosomules. These were as follows: (1) in tegument, formation of transient microvilli, a hepatalaminate outer membrane and accented surface invaginations, loss of glycocalyx, movement outward of cyton vesicles via bridges, accumulation of multilaminate bodies around bridge openings; (2) in the anterior organ (oral sucker), movement of head gland vesicles via the ducts into tegument followed by collapse of the gland fundus, disappearance of the circumfundal cells and two large support cells, and the appearance in these areas of membranes and parenchymal cells; (3) secretion of the acetabular gland contents, collapse of the glands and replacement by membranes and parenchymal cells; (4) peristaltic activity of the digestive tract as shown by alternate areas of lumen constriction and dilation; (5) loss of bladder and contraction of the small aboral collecting tubules; and (6) conversion of heterochromatic parenchymal cell nuclei to euchromatic. In contrast, the 1-hr in vitro shear schistosomules resembled 30-min in vivo schistosomules, retaining many cercarial features.     

Echinococcus granulosus: host lymphocyte transformation by parasite antigens.

Lymphocyte transformation, measured by in vitro tritiated thymidine incorporation, and indirect hemagglutination tests were carried out on hydatid patients and normal individuals using sheep and human hydatid fluid or scolex antigens. The hydatid patients showed statistically significant lymphocyte transformation with human and sheep hydatid fluid or scolex antigens when compared to normal individuals. The indirect hemagglutination tests resulted in high titers of antibody with sheep or human hydatid fluid antigens, while very low titers were obtained with scolex antigens. Unlike in the indirect hemagglutination test, the source of the antigen, scolex or fluid, was not of consequence in the lymphocyte transformation test. Furthermore, there was no correlation between the results of the serologic and lymphocyte transformation tests, since some patients with very high lymphocyte stimulation indices produced low indirect hemagglutination titers and vice versa. Similar results were obtained from rabbits which were immunized with sheep hydatid fluid or scolex extracts. The skin tests were of the immediate type of hypersensitivity reactions. Delayed skin reactions did not occur in spite of the presence of sensitized lymphocytes in the blood of the immunized rabbits.     

应用iTRAQ技术分析滩羊二毛期不同花穗型裘皮差异蛋白

为了解二毛期时滩羊串子花型裘皮与其它类型裘皮中蛋白质的差异,本试验采用iTRAQ技术及LC-MS/MS蛋白质组学研究方法,对串子花型、软大花型、绿豆丝型及其它不规则型花穗裘皮蛋白质进行鉴定和筛选,并运用Proteome Discoverer l.4软件进行定量分析,结合数据库搜索,鉴定出具有显著表达差异的蛋白,同时应用生物学技术对其进行GO和Pathway分析。结果显示4类花穗型裘皮共检测出2 886个蛋白,其中有135个、142个、113个差异蛋白分别存在于软大花型与串子花型、绿豆丝型与串子花型、其它不规则型与串子花型3个对比组中。对有表达差异的蛋白进行分析,发现膜联蛋白与血管内皮生长因子可能与软大花型毛股形成相关,KAP3和KAP6可能与滩羊串子花型毛股结构相关。研究发现滩羊不同二毛裘皮蛋白水平上的差异,可为选育优良的滩羊串子花型二毛裘皮提供理论基础。     

Assessment of skin dose in breast cancer radiotherapy: on-phantom measurement and Monte Carlo simulation

AimThe main purpose of the present study is assessment of skin dose in breast cancer radiotherapy.BackgroundAccurate assessment of skin dose in radiotherapy can provide useful information for clinical considerations.Materials and methodsA RANDO phantom was irradiated using a 6 MV Siemens Primus linac with medial and tangential radiotherapy fields for simulating breast cancer treatment. Dosimetry was also performed on various positions across the fields using an EBT3 radiochromic film. Similar conditions of measurement on the RANDO phantom including field size, irradiation angle, number of fields, etc. were subsequently simulated via the Monte Carlo N-Particle Transport code (MCNP). Ultimately, dose values for corresponding points from both methods were compared.ResultsConsidering dosimetry using radiochromic films on the RANDO phantom, there were points having underdose and overdose based on the prescribed dose and skin tolerance levels. In this respect, 81.25% and 18.75% of the points had underdose and overdose, respectively. In some cases, several differences were observed between the measurement and the MCNP simulation results associated with skin dose.ConclusionBased on the results of the points which had underdose, it was suggested that a bolus should be used for the given points. With regard to overdose points, it was advocated to consider skin tolerance dose in treatment planning. Differences between the measurement and the MCNP simulation results might be due to voxel size of tally cells in simulations, effect of beam’s angle of incidence, validation time of linac’s head, lack of electronic equilibrium in the build-up region, as well as MCNP tally type.     

Plant derived coumestrol phytochemical targets human skin carcinoma cells by inducing mitochondrial-mediated apoptosis,cell cycle arrest,inhibition of cell migration and invasion and modulation of m-TOR/PI3K/AKT signalling pathway

The current study was undertaken to investigate anticancer activity of coumestrol phytoestrogen against human skin cancer. MTT assay was performed for cell viability assessment and clonogenic assay for cell colony formation assessment. Apoptosis was analysed by Annexin V/FITC staining, AO/EB staining and western blotting assays. Effects on the m-TOR/PI3K/AKT signalling pathway were investigated by western blotting. Results indicated that coumestrol induced significant toxicity in human skin cancer cells in contrast to mouse skin cancer cells. The proliferation rate in normal skin cells remained almost intact. Annexin V-FITC and AO/EB staining assays indicated coumestrol induced cytotoxicity in skin cancer cells is mediated through apoptosis stimulation. The apoptosis in skin cancer cells was mediated through caspase-activation. Cell migration and invasion was inhibited by coumestrol in human skin cancer cells via inhibition of MMP-2 and MMP-9 expressions. Moreover, m-TOR/PI3K/AKT signalling pathway in SKEM-5 cells was blocked by coumestrol.     

In vivo measurement of surface skin strain during human gait to improve the design of rehabilitation devices

Abstract

When designing any rehabilitation, sportswear or exoskeleton device the mechanical behaviour of the body segment must be known, specifically the skin, because an excessive tissue strain may lead to ulceration and bedsores. To date, it is not known if the kinematic variability between subjects have an effect on the skin strain field, and therefore, in the design and manufacturing of rehabilitation products, such as orthoses. Several studies have analysed the skin deformation during human motion, nevertheless, the comparison between the skin strain field in different subjects during normal or pathological gait has not been reported yet. This work presents a comparison of skin strain analysis for different gait patterns to study the differences between people and, specifically, if it is possible to standardize the orthotic design between subjects with the same gait disorder. Moreover, the areas with relatively minimum strain during the ankle-foot motion are compared to improve the design of structural parts of rehabilitation devices. In this case, a validated 3D digital image correlation system has been used for this purpose combined with strain ellipse theory. The results demonstrate variations in the skin strain field between subjects with the same pathology and similarities between subjects with normal gait. However, more studies and experiments are necessaries to validate this hypothesis and also to test it between different gait pathologies.