Liquid-Solid Phase-Inversion PLGA Implant for the Treatment of Residual Tumor Tissue after HIFU Ablation

BackgroundHIFU has been shown to be a more suitable alternative for the treatment of primary solid tumors and metastatic diseases than other focal heat ablation techniques due to its noninvasive and extracorporeal nature. However, similar to other focal heat ablation techniques, HIFU is still in need of refinements due to tumor recurrence.MethodsIn this work, we investigated the effectiveness of an adjunct treatment regimen using doxorubicin (DOX)-loaded, injectable, in situ-forming, and phase-inverting PLGA as the second line of defense after HIFU ablation to destroy detrimental residual tumors and to prevent tumor recurrence. All of the statistical analyses were performed using the Statistical Package for the Social Sciences 18.0(SPSS, Inc., Chicago, IL, USA), and p< 0.05 was considered statistically significant. All of the results are presented as the means ± STDEV (standard deviation). For multiple comparisons, ANOVA (differences in tumor volumes, growth rates, apoptosis, proliferation indexes, and Bcl-2 and Bax protein levels) was used when the data were normally distributed with homogenous variance, and rank sum tests were used otherwise. Once significant differences were detected, Student-t tests were used for comparisons between two groups.ResultsOur results revealed that DOX diffused beyond the ablated tissue regions and entered tumor cells that were not affected by the HIFU ablation. Our results also show that HIFU in concert with DOX-loaded PLGA led to a significantly higher rate of tumor cell apoptosis and a lower rate of tumor cell proliferation in the areas beyond the HIFU-ablated tissues and consequently caused significant tumor volume shrinkage (tumor volumes:0.26±0.1,1.09±0.76, and 1.42±0.9cm³ for treatment, sham, and no treatment control, respectively).ConclusionsFrom these results, we concluded that the intralesional injection of DOX-loaded PLGA after HIFU ablation is significantly more effective than HIFU alone for the treatment of solid tumors.     

Rational Engineering of Recombinant Picornavirus Capsids to Produce Safe,Protective Vaccine Antigen

Foot-and-mouth disease remains a major plague of livestock and outbreaks are often economically catastrophic. Current inactivated virus vaccines require expensive high containment facilities for their production and maintenance of a cold-chain for their activity. We have addressed both of these major drawbacks. Firstly we have developed methods to efficiently express recombinant empty capsids. Expression constructs aimed at lowering the levels and activity of the viral protease required for the cleavage of the capsid protein precursor were used; this enabled the synthesis of empty A-serotype capsids in eukaryotic cells at levels potentially attractive to industry using both vaccinia virus and baculovirus driven expression. Secondly we have enhanced capsid stability by incorporating a rationally designed mutation, and shown by X-ray crystallography that stabilised and wild-type empty capsids have essentially the same structure as intact virus. Cattle vaccinated with recombinant capsids showed sustained virus neutralisation titres and protection from challenge 34 weeks after immunization. This approach to vaccine antigen production has several potential advantages over current technologies by reducing production costs, eliminating the risk of infectivity and enhancing the temperature stability of the product. Similar strategies that will optimize host cell viability during expression of a foreign toxic gene and/or improve capsid stability could allow the production of safe vaccines for other pathogenic picornaviruses of humans and animals.     

Inhibition of Klenow DNA polymerase and poly(A)-specific ribonuclease by aminoglycosides

Aminoglycosides are known to bind and perturb the function of catalytic RNA. Here we show that they also are potent inhibitors of protein-based catalysis using Escherichia coli Klenow polymerase (pol) and mammalian poly(A)-specific ribonuclease (PARN) as model enzymes. The inhibition was pH dependent and released in a competitive manner by Mg2+. Kinetic analysis showed that neomycin B behaved as a mixed noncompetitive inhibitor. Iron-mediated hydroxyl radical cleavage was used to show that neomycin B interfered with metal-ion binding in the active sites of both enzymes. Our analysis suggests a mechanism of inhibition where the aminoglycoside binds in the active site of the enzyme and thereby displaces catalytically important divalent metal ions. The potential causes of aminoglycoside toxicity and the usage of aminoglycosides to probe, characterize, and perturb metalloenzymes are discussed.     

Hydrophobic chromatography of the HL-60 cellular fraction co-binding with hexamethylene bisacetamide

Methods of separating N-acetyl-1,6-diaminohexane (NADAH) and its immobilization to diol-silica have been developed. Hexamethylene bisacetamide (HMBA) and its metabolite NADAH are used as inducers of leukemia cell differentiation. The inducing mechanism of HMBA is still not clear. Experiments show that HMBA and NADAH undergo relatively strong hydrophobic reactions and do not readily undergo ion-exchange with the proteins of the cytosolic fraction of HL-60 cells during immobilization of NADAH; the retention time of the proteins was longer than that of the phosphatides. These results show that the adsorption of HMBA and NADAH to proteins was higher than that to phosphatides. The expected biospecific receptor binding with HMBA has not been found.     

Assignment of 1H, 13C and 15N resonances of the reduced human IgG1 CH3 domain

Here we report the NMR resonance assignments for the reduced form of human IgG1 C_H3 domain, a 26 kDa dimer in solution (residues 341–447). The assignments have been deposited in the BioMagResBank with a BMRB accession number of 15204.     

Odor Memory Stability after Reinnervation of the Olfactory Bulb

The olfactory system, particularly the olfactory epithelium, presents a unique opportunity to study the regenerative capabilities of the brain, because of its ability to recover after damage. In this study, we ablated olfactory sensory neurons with methimazole and followed the anatomical and functional recovery of circuits expressing genetic markers for I7 and M72 receptors (M72-IRES-tau-LacZ and I7-IRES-tau-GFP). Our results show that 45 days after methimazole-induced lesion, axonal projections to the bulb of M72 and I7 populations are largely reestablished. Furthermore, regenerated glomeruli are re-formed within the same areas as those of control, unexposed mice. This anatomical regeneration correlates with functional recovery of a previously learned odorant-discrimination task, dependent on the cognate ligands for M72 and I7. Following regeneration, mice also recover innate responsiveness to TMT and urine. Our findings show that regeneration of neuronal circuits in the olfactory system can be achieved with remarkable precision and underscore the importance of glomerular organization to evoke memory traces stored in the brain.