Biologically inspired control of physically simulated bipeds

Summary The basic rhythmicity underlying animal locomotion is created by dedicated neural structures called central pattern generators (CPGs). We describe the implementation of such structures in simulation and their successful use for the control of bipedal walking. Artificial evolution (in the form of genetic algorithms) is used as the optimisation procedure. Two CPG types are illustrated, the more advanced of which being based on recent theoretical findings on the nature of neural architectures required to drive animal locomotion. It is shown that CPGs in conjunction with simple reflex responses as well as an appropriate mechanical implementation of the biped are capable of producing stable walking patterns on planar surfaces. This finding corroborates circumstantial experimental evidence that limited bipedal locomotion is possible without the employment of higher level control centres.     

Molecular cloning of major histocompatibility complex class II B gene cDNA from the Bengalese finch Lonchura striata

The only avian major histocompatibility complex (Mhc) genes thus far identified are from species of the relatively small order of Galliformes, while by far the largest order of Passeriformes (songbirds), containing some 60% of extant bird species, has not been studied at all in this regard. The Galliformes emerged more than 55 million years (my) ago, the Passeriformes some 25 my ago. Because of the potential for the use of Mhc genes as markers in the study of songbird populations, an attempt was made to clone class II B genes of a passeriform species, the Bangalese finch Lonchura striata acuticauda. Using a set of primers designed on the basis of known sequences, a probe corresponding to part of exon II was obtained by the polymerase chain reaction. The probe was then used to screen a Bengalese finch cDNA library and to isolate and sequence two nearly full-length clones. The sequences reveal the presence of one presumably functional class II B locus in this bird species.     

The role of tumor microenvironment in prostate cancer bone metastasis

Prostate cancer (PCa) epithelial cells require a number of factors to facilitate their establishment and growth at a distant site of metastasis. Their ability to adapt to their microenvironment, proliferate and recruit an underlying stroma is integral to the survival and growth of the metastasis. PCa predominantly metastasizes to the bone, and bone metastases are the main cause of morbidity. The bone marrow provides a permissive environment for the formation of a metastasis. In some cases, the cells may remain dormant for some time, eventually proliferating in response to an unknown "trigger." The marrow is rich in progenitor cells that differentiate into numerous cell types, producing new blood vessels, supporting fibroblasts, and an underlying extracellular matrix (ECM) that form the reactive stroma. By secreting a number of cytokines, growth factors and proteases they recruit auxiliary cells required to produce a functional stroma. These components are involved in a reciprocal interaction between the stroma and the PCa cells, allowing for the growth and survival of the tumor. Left unchecked, once a PCa tumor has established itself in the bone marrow it will eventually replace the marrow, interrupting bone homeostasis and typically promoting an osteoblastic response in the bone including osteoclastic events. The abundant deposition of new woven bone results in nerve compression, bone pain and an increase in fractures in patients with PCa bone metastases. This review will examine the tumor microenvironment, its role in facilitating tumor dissemination, growth and the resultant pathologies associated with PCa bone metastasis.     

Treatment of Helicobacter pylori infection 2012

Helicobacter pylori resistance rates to antibiotics vary in different countries and even in different regions of the same country. Choice of treatment is strongly dependent on antibiotic resistance rates. In some countries, triple therapy with a proton-pump inhibitor, amoxicillin, and clarithromycin is still the best option, but eradication results fall short of what would be desired (90-95%) in countries with clarithromycin resistance >20%, bismuth-containing quadruple therapy, or nonbismuth sequential or concomitant therapies may then be the preferred option. Newer antibiotic regimens are awaited. Vaccination would be the best option, especially for developing countries, but little progress has been made in designing a vaccine.     

Prevalence and identity of Cryptosporidium spp. in pig slurry

Cryptosporidium spp. were detected in 25 of 56 pig slurry samples from 33 Irish farms by PCR and DNA sequencing. The organisms detected included C. suis, Cryptosporidium pig genotype II, and C. muris. We concluded that Cryptosporidium oocysts can persist in treated slurry and potentially contaminate surface water through improper discharge or uncontrolled runoff.