Thermosensitive hydrogels of poly(methyl vinyl ether-co-maleic anhydride) - Pluronic (R) F127 copolymers for controlled protein release

Thermosensitive hydrogels are of a great interest due to their many biomedical and pharmaceutical applications. In this study, we synthesized a new series of random poly (methyl vinyl ether-co-maleic anhydride) (Gantrez (R) AN, GZ) and Pluronic (R) F127 (PF127) copolymers (GZ-PF127), that formed thermosensitive hydrogels whose gelation temperature and mechanical properties could be controlled by the molar ratio of GZ and PF127 polymers and the copolymer concentration in water. Gelation temperatures tended to decrease when the GZm/PF127 ratio increased. Thus, at a fixed GZm/PF127 value, sol-gel temperatures decreased at higher copolymer concentrations. Moreover, these hydrogels controlled the release of proteins such as bovine serum albumin (BSA) and recombinant recombinant kinetoplastid membrane protein of Leishmania (rKMP-11) more than the PF127 system. Toxicity studies carried out in J774.2 macrophages showed that cell viability was higher than 80%. Finally, histopathological analysis revealed that subcutaneous administration of low volumes of these hydrogels elicited a tolerable inflammatory response that could be useful to induce immune responses against the protein cargo in the development of vaccine adjuvants.

The prognostic value of the stem-like group in colorectal cancer using a panel of immunohistochemistry markers

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the Western world. It is becoming increasingly clear that CRC is a diverse disease, as exemplified by the identification of subgroups of CRC tumours that are driven by distinct biology. Recently, a number of studies have begun to define panels of diagnostically relevant markers to align patients into individual subgroups in an attempt to give information on prognosis and treatment response. We examined the immunohistochemical expression profile of 18 markers, each representing a putative role in cancer development, in 493 primary colorectal carcinomas using tissue microarrays. Through unsupervised clustering in stage II cancers, we identified two cluster groups that are broadly defined by inflammatory or immune-related factors (CD3, CD8, COX-2 and FOXP3) and stem-like factors (CD44, LGR5, SOX2, OCT4). The expression of the stem-like group markers was associated with a significantly worse prognosis compared to cases with lower expression. In addition, patients classified in the stem-like subgroup displayed a trend towards a benefit from adjuvant treatment. The biologically relevant and poor prognostic stem-like group could also be identified in early stage I cancers, suggesting a potential opportunity for the identification of aggressive tumors at a very early stage of the disease.

The reliability of R50 as a measure of vulnerability of food webs to sequential species deletions

Recent studies predict elevated and accelerating rates of species extinctions over the 21st century, due to climate change and habitat loss. Considering that such primary species loss may initiate cascades of secondary extinctions and push systems towards critical tipping points, we urgently need to increase our understanding of if certain sequences of species extinctions can be expected to be more devastating than others Most theoretical studies addressing this question have used a topological (non-dynamical) approach to analyse the probability that food webs will collapse, below a fixed threshold value in species richness, when subjected to different sequences of species loss. Typically, these studies have neither considered the possibility of dynamical responses of species, nor that conclusions may depend on the value of the collapse threshold. Here we analyse how sensitive conclusions on the importance of different species are to the threshold value of food web collapse. Using dynamical simulations, where we expose model food webs to a range of extinction sequences, we evaluate the reliability of the most frequently used index, R<inf>50</inf>, as a measure of food web robustness. In general, we find that R<inf>50</inf> is a reliable measure and that identification of destructive deletion sequences is fairly robust, within a moderate range of collapse thresholds. At the same time, however, focusing on R<inf>50</inf> only hides a lot of interesting information on the disassembly process and can, in some cases, lead to incorrect conclusions on the relative importance of species in food webs.

Diagnostic value of increased sensitivity by massively parallel sequencing

Routine molecular diagnostics modalities are unable to confidently detect low frequency mutations (<5-15%) that may indicate response to targeted therapies. We confirm the presence of a low frequency NRAS mutation in a rectal cancer patient using massively parallel sequencing when previous Sanger sequencing results proved negative and Q-PCR testing inconclusive. There is increasing evidence that these low frequency mutations may confer resistance to anti-EGFR therapy. In view of negative/inconclusive Sanger sequencing and Q-PCR results for NRAS mutations in a KRAS wt rectal case, the diagnostic biopsy and 4 distinct subpopulations of cells in the resection specimen after conventional chemo/radiotherapy were massively parallel sequenced using the Ion Torrent PGM. DNA was derived from FFPE rectal cancer tissue and amplicons produced using the Cancer Hotspot Panel V2 and sequenced using semiconductor technology. NRAS mutations were observed at varying frequencies in the patient biopsy (12.2%) and all four subpopulations of cells in the resection with an average frequency of 7.3% (lowest 2.6%). The results of the NGS also provided the mutational status of 49 other genes that may have prognostic or predictive value, including KRAS and PIK3CA. NGS technology has been postulated in diagnostics because of its capability to generate results in large panels of clinically meaningful genes in a cost-effective manner. This case illustrates another potential advantage of this technology: its use for detecting low frequency mutations that may influence therapeutic decisions in cancer treatment.

The prognostic and therapeutic value of EpHA2 in early colorectal cancer (CRC).

Background: EpHA2 is a 130 kD transmembrane glycoprotein belonging to ephrin receptor subfamily and involved in angiogenesis/tumour neovascularisation. High EpHA2 mRNA level has recently been implicated in cetuximab resistance. Previously, we found high EpHA2 levels in a panel of invasive colorectal cancer (CRC) cells, which was associated with high levels of stem-cell marker CD44. Our aim was to investigate the prognostic value of EpHA2 and subsequently correlate expression levels to known clinico-pathological variables in early stage CRC. Methods: Tissue samples from 509 CRC patients were analysed. EpHA2 expression was measured using IHC. Kaplan-Meier graphs were used. Univariate and multivariate analyses employed Cox Proportional Hazards Ratio (HR) method. A backward selection method (Akaike’s information criterion) was used to determine a refined multivariate model. Results: EpHA2 was highly expressed in CRC adenocarcinoma compared to matched normal colon tissue. In support of our preclinical invasive models, strong correlation was found between EpHA2 expression and CD44 and Lgr5 staining (p<0.001). In addition, high EpHA2 expression significantly correlated with vascular invasion (p=0.03).HR for OS for stage II/III patients with high EpHA2 expression was 1.69 (95%CI: 1.164-2.439; p=0.003). When stage II/III was broken down into individual stages, there was significant correlation between high EpHA2 expression and poor 5-years OS in stage II patients (HR: 2.18; 95%CI: 1.28-3.71; p=0.005).HR in the stage III group showed a trend to statistical significance (HR: 1.48; 95%CI=0.87-2.51; p=0.05). In both univariate and multivariate analyses of stage II patients, high EpHA2 expression was the only significant factor and was retained in the final multivariate model. Higher levels of EpHA2 were noted in our RAS and BRAF mutant CRC cells, and silencing EpHA2 resulted in significant decreases in migration/invasion in parental and invasive CRC sublines. Correlation between KRAS/NRAS/BRAFmutational status and EpHA2 expression in clinical samples is ongoing. Conclusions: Taken together, our study is the first to indicate that EpHA2 expression is a predictor of poor clinical outcome and a potential novel target in early stage CRC.

A high-value, low-cost bubble continuous positive airway pressure system for low-resource settings:technical assessment and initial case reports

Acute respiratory infections are the leading cause of global child mortality. In the developing world, nasal oxygen therapy is often the only treatment option for babies who are suffering from respiratory distress. Without the added pressure of bubble Continuous Positive Airway Pressure (bCPAP) which helps maintain alveoli open, babies struggle to breathe and can suffer serious complications, and frequently death. A stand-alone bCPAP device can cost $6,000, too expensive for most developing world hospitals. Here, we describe the design and technical evaluation of a new, rugged bCPAP system that can be made in small volume for a cost-of-goods of approximately $350. Moreover, because of its simple design--consumer-grade pumps, medical tubing, and regulators--it requires only the simple replacement of a <$1 diaphragm approximately every 2 years for maintenance. The low-cost bCPAP device delivers pressure and flow equivalent to those of a reference bCPAP system used in the developed world. We describe the initial clinical cases of a child with bronchiolitis and a neonate with respiratory distress who were treated successfully with the new bCPAP device.