Biocompatibility of silk-tropoelastin protein polymers

Blended polymers are used extensively in many critical medical conditions as components of permanently implanted devices. Hybrid protein polymers containing recombinant human tropoelastin and silk fibroin have favorable characteristics as implantable scaffolds in terms of mechanical and biological properties. A firefly luciferase transgenic mouse model was used to monitor real-time IL-1β production localized to the site of biomaterial implantation, to observe the acute immune response (up to 5 days) to these materials. Significantly reduced levels of IL-1β were observed in silk/tropoelastin implants compared to control silk only implants at 1, 2 and 3 days post-surgery. Subsequently, mice (n = 9) were euthanized at 10 days (10D) and 3 weeks (3W) post-surgery to assess inflammatory cell infiltration and collagen deposition, using histopathology and immunohistochemistry. Compared to control silk only implants, fewer total inflammatory cells were found in silk/tropoelastin (∼29% at 10D and ∼47% at 3W). Also fewer ingrowth cells (∼42% at 10D and ∼63% at 3W) were observed within the silk/tropoelastin implants compared to silk only. Lower IL-6 (∼52%) and MMP-2 (∼84%) (pro-inflammatory) were also detected for silk/tropoelastin at 10 days. After 3 weeks implantation, reduced neovascularization (vWF ∼43%), fewer proliferating cells (Ki67 ∼58% and PCNA ∼41%), macrophages (F4/80 ∼64%), lower IL-10 (∼47%) and MMP-9 (∼55%) were also observed in silk/tropoelastin materials compared to silk only. Together, these results suggest that incorporation of tropoelastin improves on the established biocompatibility of silk fibroin, uniquely measured here as a reduced foreign body inflammatory response.     

Advantages and limitations of the autofluorescent diagnostics of the laryngeal cancer and precancerosis

Any endoscopic diagnostic procedure that is capable of giving exact information on laryngeal lesions without damaging the tissue has essential advantages over standard biopsy. Tissue autofluorescence is defined as a natural ability of tissue to fluoresce when exposed to a certain light wavelength. This feature is a consequence of the presence of fluorophores in the tissues, which are activated by a narrow wavelength range. However, due to their biochemical and biophysical characteristics, laryngeal precancerosis and cancer do not fluoresce when exposed to blue light. In the present study, we used Pentax’s System of Autofluorescent Endoscopy (SAFE 1000) to detect autofluorescence disturbances from laryngeal mucosa. Diagnostic parameters (sensitivity and specificity) of the microlaryngoscopy (MLS) and SAFE 1000 in the diagnosis of laryngeal precancerosis and carcinoma were compared and discussed. We have found that SAFE had a better sensitivity with regard to mentioned laryngeal pathology, but MLS had better specificity than SAFE. The overall diagnostic sensitivity in the diagnostics of laryngeal atypical hyperplasia and cancer with SAFE was 89%, as opposed to 73% with MLS. Diagnostic specificity of SAFE for all cases of laryngeal carcinomas and atypical hyperplasia was 78%. The specificity of MLS in diagnostics of laryngeal carcinomas cases was 98%, while that for cases of atypical hyperplasia was 100%. Many other conditions that have impact on autofluorescent features of laryngeal mucosa were also discussed.     

In vivo observation of intracellular oximetry in perfluorocarbon‐labeled glioma cells and chemotherapeutic response in the CNS using fluorine‐19 MRI

Preclinical development of therapeutic agents against cancer could greatly benefit from noninvasive markers of tumor killing. Potentially, the intracellular partial pressure of oxygen (pO₂) can be used as an early marker of antitumor efficacy. Here, the feasibility of measuring intracellular pO₂ of central nervous system glioma cells in vivo using ¹⁹F magnetic resonance techniques is examined. Rat 9L glioma cells were labeled with perfluoro‐15‐crown‐5‐ether ex vivo and then implanted into the rat striatum. ¹⁹F MRI was used to visualize tumor location in vivo. The mean ¹⁹F T₁ of the implanted cells was measured using localized, single‐voxel spectroscopy. The intracellular pO₂ in tumor cells was determined from an in vitro calibration curve. The basal pO₂ of 9L cells (day 3) was determined to be 45.3 ± 5 mmHg (n = 6). Rats were then treated with a 1× LD10 dose of bischloroethylnitrosourea intravenously and changes in intracellular pO₂ were monitored. The pO₂ increased significantly (P = 0.042, paired T‐test) to 141.8 ± 3 mmHg within 18 h after bischloroethylnitrosourea treatment (day 4) and remained elevated (165 ± 24 mmHg) for at least 72 h (day 6). Intracellular localization of the perfluoro‐15‐crown‐5‐ether emulsion in 9L cells before and after bischloroethylnitrosourea treatment was confirmed by histological examination and fluorescence microscopy. Overall, noninvasive ¹⁹F magnetic resonance techniques may provide a valuable preclinical tool for monitoring therapeutic response against central nervous system or other deep‐seated tumors. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Height and prostate cancer risk: a large nested case-control study (ProtecT) and meta-analysis

BACKGROUND: Height, a marker of childhood environmental exposures, is positively associated with prostate cancer risk, perhaps through the insulin-like growth factor system. We investigated the relationship of prostate cancer with height and its components (leg and trunk length) in a nested case-control study and with height in a dose-response meta-analysis. METHODS: We nested a case-control study within a population-based randomized controlled trial evaluating treatments for localized prostate cancer in British men ages 50 to 69 years, including 1,357 cases detected through prostate-specific antigen testing and 7,990 controls (matched on age, general practice, assessment date). Nine bibliographic databases were searched systematically for studies on the height-prostate cancer association that were pooled in a meta-analysis. RESULTS: Based on the nested case-control, the odds ratio (OR) of prostate-specific antigen-detected prostate cancer per 10 cm increase in height was 1.06 [95% confidence interval (95% CI): 0.97-1.16; p(trend) = 0.2]. There was stronger evidence of an association of height with high-grade prostate cancer (OR: 1.23; 95% CI: 1.06-1.43), mainly due to the leg component, but not with low-grade disease (OR: 0.99; 95% CI: 0.90-1.10). In general, associations with leg or trunk length were similar. A meta-analysis of 58 studies found evidence that height is positively associated with prostate cancer (random-effects OR per 10 cm: 1.06; 95% CI: 1.03-1.09), with a stronger effect for prospective studies of more advanced/aggressive cancers (random-effects OR: 1.12; 95% CI: 1.05-1.19). CONCLUSION: These data indicate a limited role for childhood environmental exposures-as indexed by adult height-on prostate cancer incidence, while suggesting a greater role for progression, through mechanisms requiring further investigation.     

Regulatory mechanisms of fear extinction and depression-like behavior.

Human anxiety is frequently accompanied by depression, and when they co-occur both conditions exhibit greater severity and resistance to treatment. Little is known, however, about the molecular processes linking these emotional and mood disorders. Based on previously reported phosphorylation patterns of extracellular signal-regulated kinase (ERK) in the brain, we hypothesized that ERK's upstream activators intertwine fear and mood regulation through their hippocampal actions. We tested this hypothesis by studying the upstream regulation of ERK signaling in behavioral models of fear and depression. Wild-type and ERK1-deficient mice were used to study the dorsohippocampal actions of the putative ERK activators: mitogen-activated and extracellular signal-regulated kinase (MEK), protein kinase C (PKC), and cAMP-dependent protein kinase (PKA). Mice lacking ERK1 exhibited enhanced fear extinction and reduced depression caused by overactivation of ERK2. Both behaviors were reversed by inhibition of MEK, however the extinction phenotype depended on hippocampal, whereas the depression phenotype predominantly involved extrahippocampal MEK. Unexpectedly, inhibition of PKC accelerated extinction and decreased depression by ERK-independent mechanisms, whereas inhibition of PKA did not produce detectable molecular or behavioral effects in the employed paradigm. These results indicate that, contrary to fear conditioning but similar to mood stabilization, extinction of fear required upregulation of MEK/ERK and downregulation of ERK-independent PKC signaling. The dissociation of these pathways may thus represent a common mechanism for fear and mood regulation, and a potential therapeutic option for comorbid anxiety and depression.     

Protective effect of basil (Ocimum basilicum L.) against oxidative DNA damage and mutagenesis.

Mutagenic and antimutagenic properties of essential oil (EO) of basil and its major constituent Linalool, reported to possess antioxidative properties, were examined in microbial tests. In Salmonella/microsome and Escherichia. coli WP2 reversion assays both derivatives (0.25–2.0 μl/plate) showed no mutagenic effect. Salmonella. typhimurium TA98, TA100 and TA102 strains displayed similar sensitivity to both basil derivatives as non-permeable E. coli WP2 strains IC185 and IC202 oxyR. Moreover, the toxicity of basil derivatives to WP2 strains did not depend on OxyR function. The reduction of t-BOOH-induced mutagenesis by EO and Linalool (30–60%) was obtained in repair proficient strains of the E. coli K12 assay (Nikoli?, B., Stanojevi?, J., Miti?, D., Vukovi?-Ga?i?, B., Kne?evi?-Vuk?evi?, J., Simi?, D., 2004. Comparative study of the antimutagenic potential of vitamin E in different E. coli strains. Mutat. Res. 564, 31–38), as well as in E. coli WP2 IC202 strain. EO and Linalool reduced spontaneous mutagenesis in mismatch repair deficient E. coli K12 strains (27–44%). In all tests, antimutagenic effect of basil derivatives was comparable with that obtained with model antioxidant vitamin E. Linalool and vitamin E induced DNA strand breaks in Comet assay on S. cerevisiae 3A cells, but at non-genotoxic concentrations (0.075 and 0.025 μg/ml, respectively) they reduced the number of H₂O₂-induced comets (45–70% Linalool and 80–93% vitamin E). Obtained results indicate that antigenotoxic potential of basil derivatives could be attributed to their antioxidative properties.     

Variability of hemagglutinin-neuraminidase and nucleocapsid protein of vaccine and wild-type mumps virus strains.

The mumps virus (MuV) molecular evolution is characterized by the co-circulation of numerous distinct strains. Standardized phylogenetic analyses based on the nucleotide sequences of the SH gene are important for mumps surveillance, but lack the information regarding antigenic properties. So far, the location of antigenic epitopes has been determined for two MuV proteins, the hemagglutinin-neuraminidase (HN) and the nucleocapsid (N) protein. We performed multiple sequence comparisons of putative HN and N protein sequences in order to describe their diversity and plasticity, and to determine the level of similarity between vaccine and wild-type strains. The results of full-length HN or N protein phylogeny showed that MuV strains form a number of differing clades which are in concordance with grouping obtained by standard MuV genotyping. When vaccine strains are compared to all wild-type strains, the highest mean percentage of amino acid differences in both HN and N protein analysis was found for Jeryl Lynn 5 and Jeryl Lynn 2 strains while the lowest value was obtained for Leningrad-3 and L-Zagreb strains. When only 3 antigenic regions of the HN protein, comprising 45 amino acids in total, were investigated, the diversity is considerably diminished: 51.5% of all putative HN proteins show identical sequences (including those of vaccine strains L-Zagreb, Leningrad-3, Hoshino and Urabe). Another 26.5% proteins (including Miyahara vaccine strain) differ in only one amino acid, while the others differ in two to five amino acids from the most common sequence. Jeryl Lynn 2 and Jeryl Lynn 5 strains differ in four amino acids each. N protein antigenic sites have been mapped within its hypervariable C-terminus. Our results indicate that there might be genotype-specific amino acids residing in this antigenic region. The results of our study present the background information for investigations of MuV heterogeneity and antigenic diversity.