Multi-exemplar affinity propagation.

The affinity propagation (AP) clustering algorithm has received much attention in the past few years. AP is appealing because it is efficient, insensitive to initialization, and it produces clusters at a lower error rate than other exemplar-based methods. However, its single-exemplar model becomes inadequate when applied to model multisubclasses in some situations such as scene analysis and character recognition. To remedy this deficiency, we have extended the single-exemplar model to a multi-exemplar one to create a new multi-exemplar affinity propagation (MEAP) algorithm. This new model automatically determines the number of exemplars in each cluster associated with a super exemplar to approximate the subclasses in the category. Solving the model is NP-hard and we tackle it with the max-sum belief propagation to produce neighborhood maximum clusters, with no need to specify beforehand the number of clusters, multi-exemplars, and superexemplars. Also, utilizing the sparsity in the data, we are able to reduce substantially the computational time and storage. Experimental studies have shown MEAP's significant improvements over other algorithms on unsupervised image categorization and the clustering of handwritten digits.

Studies on the establishment of a co-culture system of lung stage Schistosoma japonicum with host cells.

Due to their role in eliciting protective Th1 cell-mediated immune responses in definitive hosts lung stage schistosomula are in the focus of intensive research. In vitro culture approaches in the past exhibited significant differences in gene expression profiles between lung stage schistosomula isolated from hosts and those cultured conventionally. Therefore, new approaches to culture schistosomula are of broad interest. In the present study, co-culture systems of schistosomula of Schistosoma japonicum and different vertebrate host cells were tested. Among these, human hepatic venous endothelial cells (ED25) turned out to be very suitable and interesting feeder cells. Compared with controls cultured in vitro or co-cultured with other cells, schistosomula co-cultured with ED25 cells shared more similarities in morphology and tegumental structures with schistosomula directly obtained from infected mice as microscopically determined. According to results from a suppression subtractive hybridization approach to compare transcriptional differences of co-cultured and host group or control group parasites, four candidate transcripts encoding cathepsin L precursor, heat shock protein 70, glyceraldehyde 3-phosphate dehydrogenase, and programmed cell death protein 10 were shown to be differently expressed among the three groups by real-time PCR. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis finally confirmed not only congruent protein patterns but also interesting differences among the compared schistosomula groups. The co-culture system between schistosomula of S. japonicum and ED25 cells established in the present study improved existing cultivation attempts. Although some differences to host-derived schistosomula were still observed, co-culture with ED25 cells positively influenced parasite morphology and gene expression in a more host-like manner.

Effects of protein extract from head-foot tissue of Oncomelania hupensis on the growth and gene expression of mother sporocysts of Schistosoma japonicum.

Oncomelania hupensis is the intermediate host of Schistosoma japonicum. In the present study, we investigated the effects of protein extracts from head-foot or gland tissue of O. hupensis on mother sporocysts of S. japonicum cultured in vitro. In the presence of head-foot protein extract of snails from the native province Hunan, in-vitro-transformed mother sporocysts presented not only a longer survival time and stronger motility, but also a bigger size than parasites cultured with protein extracts of glands of the same snail or head-foot tissue of a non-native snail from the Hubei province. Using suppression subtractive hybridization, two subtractive libraries were constructed on the basis of RNA of sporocysts cultured with or without native snail head-foot protein extract. A number of 31 transcripts were found to be up-regulated. Sequence analyses revealed that they represented genes involved among others in metabolic process, electron transport chain, response to chemical stimulus, and oxidation-reduction processes. Opposite to that 20 down-regulated transcripts were among others related to pseudouridine synthesis, RNA processing, and ribosome biogenesis. The differential expression of three of these transcripts, encoding cytochrome c oxidase subunit 2 (Cox2), NADH-ubiquinone oxidoreductase (ND1), and dyskeratosis congenita 1 protein (DKC1), were confirmed by real-time PCR. The promoted development and the differential gene expression of cultured sporocysts under the influence of head-foot protein extract of native O. hupensis implied not only its ability to improve in vitro culture conditions for intramolluscan stages, it may also represent a priming result with respect to the identification and characterization of factors involved in the parasite-host interplay between S. japonicum and O. hupensis.

KN-93, a specific inhibitor of CaMKII inhibits human hepatic stellate cell proliferation in vitro.

AIM: To investigate the effects of KN-93, a CaMKII selective inhibitor on cell proliferation and the expression of p53 or p21 protein in human hepatic stellate cells. METHODS: Human hepatic stellate cells (LX-2) were incubated with various concentrations (0-50 micromol/L) of KN-93 or its inactive derivative, KN-92. Cell proliferation was measured by CCK-8 assay, and the expression of two cell cycle regulators, p53 and p21, was determined by SDS-PAGE and Western blotting. RESULTS: KN-93 (5-50 micromol/L) decreased the proliferation of human hepatic stellate cells in a dose-dependent manner from 81.76% (81.76% +/- 2.58% vs 96.63% +/- 2.69%, P < 0.05) to 27.15% (27.15% +/- 2.86% vs 96.59% +/- 2.44%, P < 0.01) after 24 h treatment. Incubation of 10 micromol/L KN-93 induced the cell growth reduction in a time-dependent manner from 78.27% at 8 h to 11.48% at 48 h. However, KN-92, an inactive derivative of KN-93, did not inhibit cell proliferation effectively. Moreover, analysis of cell cycle regulator expression revealed that KN-93 rather than KN-92 reduced the expression of p53 and p21. CONCLUSION: KN-93 has potent inhibitory effect on proliferation of LX-2 cells by modulating the expression of two special cell cycle regulators, p53 and p21.

[Primary culture of the cells from Oncomelania hupensis liver].

OBJECTIVE: To develop a method for primary culture of cells from Oncomelania hupensis liver, and to observe the distribution of succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) in the cultured cells. METHODS: O. hupensis was anatomized to separate the liver. Livers were soaked in 0.2% benzalkonium bromide and washed by physiological saline containing antibiotics in turns. Cells from the liver were harvested by mechanical mulling and filtering. The isolated cells were then incubated with methods of the combination culture and standing suspension culture, respectively. The culture medium for the cells was a mixture of Medium 199 (50 ml), 0.3% lactoalbumin hydrolysate dissolved in a balanced salt solution (BBS, 30 ml), and fetal calf serum (FCS, 20 ml) containing a moderate amount of antibiotics (100 IU/ml penicillin, 100 microg/ml streptomycin and 50 microg/ml kanamycin) at pH 7.2-7.4 under the temperature of 26.5 degrees C. The cells were stained by using Giemsa and Pearson methods (for SDH and LDH respectively) to observe the shape of cultured cells and enzyme distribution in cells. The living and stained cells were microscopically observed. RESULTS: Under microscope, the attached cells incubated with method of the combination culture showed round, elliptic, triangular and irregular shapes, with more round and elliptic cells. The size was approximately (4-16) microm x (6-20) microm in average. The clustered cells with an unclear nucleus and abundant and lucid cytoplasm were smaller than diffused cells with a large, obvious nuclei and less cytoplasm. Degeneration was observed after culturing for 5-7 days. The cultured cells could be divided into two types based on the color shown after Giemsa staining. The first type cells showed blue cytoplasm and mauve nuclei while the second type cells were opposite. There were blue granules in different sizes and shade in the cytoplasm after SDH and LDH staining. It was difficult for the cells to attach the wall of the culture flask using method of the standing suspension culture. The shape of the cultured cells were almost round with unclear nuclei, and the size was about (4-6) microm x (6-8) microm in average. The cells incubated with the standing suspension method were found to be contaminated after culturing for 3 days. CONCLUSION: The combination culture method is suitable for primary culture of the cells from O. hupensis liver and the cells show activities of both SDH and LDH in cytoplasm.