Difference in Membrane Repair Capacity Between Cancer Cell Lines and a Normal Cell Line

Electroporation-based treatments and other therapies that permeabilize the plasma membrane have been shown to be more devastating to malignant cells than to normal cells. In this study, we asked if a difference in repair capacity could explain this observed difference in sensitivity. Membrane repair was investigated by disrupting the plasma membrane using laser followed by monitoring fluorescent dye entry over time in seven cancer cell lines, an immortalized cell line, and a normal primary cell line. The kinetics of repair in living cells can be directly recorded using this technique, providing a sensitive index of repair capacity. The normal primary cell line of all tested cell lines exhibited the slowest rate of dye entry after laser disruption and lowest level of dye uptake. Significantly, more rapid dye uptake and a higher total level of dye uptake occurred in six of the seven tested cancer cell lines (p < 0.05) as well as the immortalized cell line (p < 0.001). This difference in sensitivity was also observed when a viability assay was performed one day after plasma membrane permeabilization by electroporation. Viability in the primary normal cell line (98 % viable cells) was higher than in the three tested cancer cell lines (81–88 % viable cells). These data suggest more effective membrane repair in normal, primary cells and supplement previous explanations why electroporation-based therapies and other therapies permeabilizing the plasma membrane are more effective on malignant cells compared to normal cells in cancer treatment.     

Effect of Protein, Polysaccharide, and Oxygen Concentration Profiles on Biofilm Cohesiveness

It is important to control biofilm cohesiveness to optimize process performance. In this study, a membrane-aerated biofilm reactor inoculated with activated sludge was used to grow mixed-culture biofilms of different ages and thicknesses. The cohesions, or cohesive energy levels per unit volume of biofilm, based on a reproducible method using atomic force microscopy (F. Ahimou, M. J. Semmens, P. J. Novak, and G. Haugstad, Appl. Environ. Microbiol. 73:2897-2904, 2007), were determined at different locations within the depths of the biofilms. In addition, the protein and polysaccharide concentrations within the biofilm depths, as well as the dissolved oxygen (DO) concentration profiles within the biofilms, were measured. It was found that biofilm cohesion increased with depth but not with age. Level of biofilm cohesive energy per unit volume was strongly correlated with biofilm polysaccharide concentration, which increased with depth in the membrane-aerated biofilm. In a 12-day-old biofilm, DO also increased with depth and may therefore be linked to polysaccharide production. In contrast, protein concentration was relatively constant within the biofilm and did not appear to influence cohesion.     

Fine needle aspiration cytology of papillary endothelial hyperplasia. A case report.

BACKGROUND: Papillary endothelial hyperplasia is an intravascular or rarely extravascular proliferation of endothelial cells. It is considered an unusual form of thrombus organization. CASE: A 41-year-old, healthy male presented with a neck mass, which was aspirated. The cytomorphologic features were interpreted as consistent with squamous cell carcinoma. Subsequent workup failed to reveal a primary lesion, and the mass was surgically excised. Histopathology showed papillary endothelial hyperplasia associated with a hematoma. Immunocytochemical staining for factor VIII-related antigen on a destained, alcohol-fixed smear from the fine needle aspirate confirmed the endothelial nature of the cells. CONCLUSION: A vascular lesion should be considered in a fine needle aspiration biopsy of a head and neck mass, in particular when the clinical features are not consistent with a metastatic malignancy. The absence of cytoplasmic orangeophilia and immunoreactivity for factor VIII-related antigen may be helpful in establishing the diagnosis.     

Pair-rearing infant monkeys (Macaca nemestrina) using a “rotating-peer” strategy

Appropriate rearing conditions for captive primates are important for both research and breeding purposes. In an earlier study, pigtailed macaque infants that were pair-reared with a single continuous partner exhibited excessive social clinging and could not adapt to living in large social groups at 8–10 months of age. In the present study, eight macaques were pair-reared until they were 6 months old. Each member of an animal's four-monkey social group served as a home-cage partner. In an attempt to reduce excessive mutual clinging, the pairs were rotated every 2–3 days to increase the variability of social stimulation in the home cage. However, these infants developed abnormal social behaviors that were in some cases even more extreme than those exhibited by infants pair-reared with a single continuous partner. A second goal of this experiment was to study interlaboratory reliability for the development of social behavior. The animals were divided into two groups, one housed in a nursery and the other in a biological safety level 3 virus laboratory. Some differences were detected between the two groups, demonstrating the necessity of controls in biobehavioral developmental research. Am. J. Primatol. 41:141–149, 1997. © 1997 Wiley-Liss, Inc.     

Bayesian characterization of uncertainty in species interaction strengths

Considerable effort has been devoted to the estimation of species interaction strengths. This effort has focused primarily on statistical significance testing and obtaining point estimates of parameters that contribute to interaction strength magnitudes, leaving the characterization of uncertainty associated with those estimates unconsidered. We consider a means of characterizing the uncertainty of a generalist predator’s interaction strengths by formulating an observational method for estimating a predator’s prey-specific per capita attack rates as a Bayesian statistical model. This formulation permits the explicit incorporation of multiple sources of uncertainty. A key insight is the informative nature of several so-called non-informative priors that have been used in modeling the sparse data typical of predator feeding surveys. We introduce to ecology a new neutral prior and provide evidence for its superior performance. We use a case study to consider the attack rates in a New Zealand intertidal whelk predator, and we illustrate not only that Bayesian point estimates can be made to correspond with those obtained by frequentist approaches, but also that estimation uncertainty as described by 95% intervals is more useful and biologically realistic using the Bayesian method. In particular, unlike in bootstrap confidence intervals, the lower bounds of the Bayesian posterior intervals for attack rates do not include zero when a predator–prey interaction is in fact observed. We conclude that the Bayesian framework provides a straightforward, probabilistic characterization of interaction strength uncertainty, enabling future considerations of both the deterministic and stochastic drivers of interaction strength and their impact on food webs.     

Do upstream migrating,juvenile amphidromous shrimps,provide a marine subsidy to river ecosystems?

相似文献   

Lasioglossins LLIII affect the morphogenesis of Candida albicans and reduces the duration of experimental vaginal candidiasis in mice

Lasioglossins are a group of peptides with identified antimicrobial activity. The inhibitory effects of two synthetic lasioglossin derivatives, LLIII and D‐isomeric variant LLIII‐D, on morphological changes in Candida albicans in vitro and the effect of local administration of LLIII during experimental murine candidiasis were investigated. C. albicans blastoconidia were grown in the presence of lasioglossin LLIII or LLIII‐D at concentrations of 11.5 μM and 21 μM, respectively, for 1, 2 and 3 days and their viability determined by flow cytometry using eosin Y staining. Morphological changes were examined by light and fluorescent microscopy. The Candida‐inhibitory effect of daily intravaginal administration of 0.7 or 1.4 μg of LLIII was assessed in mice with experimentally‐induced vaginal candidiasis. LLIII and LLIII‐D lasioglossins exhibited candidacidal activity in vitro (>76% after 24 hr and >84% after 48 hr of incubation). After 72 hr incubation of Candida with low concentration of lasioglossins, an increase in viability was detected, probably due to a Candida antimicrobial peptides evasion strategy. Furthermore, lasioglossins inhibited temperature‐induced morphotype changes toward hyphae and pseudohyphae with sporadic occurrence of atypical cells with two or enlarged nuclei, suggesting interference with mitosis or cytokinesis. Local application of LLIII reduced the duration of experimental candidiasis with no evidence of adverse effects. Lasioglossin LLIII is a promising candidate for development as an antimicrobial drug for treating the vaginal candidiasis.