Evaluation of a Prednisolone Acetate-Loaded Subconjunctival Implant for the Treatment of Recurrent Uveitis in a Rabbit Model

Aim

To assess the efficacy of a biodegradable, prednisolone acetate implant in a rabbit uveitis model.

Methods

Randomized, controlled study of biodegradable microfilms preloaded with prednisolone acetate (PA) in a rabbit uveitis model. Experimental uveitis was induced by unilateral intravitreal injection of Mycobacterium tuberculosis H37Ra antigen (50 ug; 1 ug/uL) in preimmunized rabbits. PA-loaded poly[d,l-lactide-co-ε-caprolactone] (PLC) microfilms (n = 10) and blank microfilms (n = 6) were implanted subconjunctivally. An estimate of PA release in vivo was calculated from measured residual PA amounts in microfilms after the rabbits were sacrificed. The eyes were clinically monitored for ocular inflammation for 28 days. Histopathological examination of the enucleated eyes was performed at the end of the study period.

Results

In vitro studies revealed that sandwich PA-loaded microfilm formulations exhibited higher release kinetic compared to homogenous PA-loaded microfilms. The 60–40–60% microfilm released an average of 0.034 mg/day of PA over the period of 60 days in vitro; and we found that approximately 0.12 mg/day PA was released in vivo. Animals implanted with the PA-loaded microfilms exhibited significantly lowered median inflammatory scores when compared against the control group in this model for recurrent uveitis (P<0.001). The implants were clinically well tolerated by all the animals. Histology results showed no significant scarring or inflammation around the PA-loaded microfilms.

Conclusion

Our pilot study demonstrated that a subconjunctival PA-loaded implant is effective in suppressing inflammation in the rabbit model of uveitis, by providing therapeutic levels of PA that attenuated the inflammatory response even after a rechallenge. Longer term studies are now needed to establish the therapeutic potential of such a delivery system for treatment of ocular inflammation.     

The Acute Phase of Experimental Cardiogenic Shock Is Counteracted by Microcirculatory and Mitochondrial Adaptations

The mechanisms contributing to multiorgan dysfunction during cardiogenic shock are poorly understood. Our goal was to characterize the microcirculatory and mitochondrial responses following ≥10 hours of severe left ventricular failure and cardiogenic shock. We employed a closed-chest porcine model of cardiogenic shock induced by left coronary microembolization (n = 12) and a time-matched control group (n = 6). Hemodynamics and metabolism were measured hourly by intravascular pressure catheters, thermodilution, arterial and organ specific blood gases. Echocardiography and assessment of the sublingual microcirculation by sidestream darkfield imaging were performed at baseline, 2±1 and 13±3 (mean±SD) hours after coronary microembolization. Upon hemodynamic decompensation, cardiac, renal and hepatic mitochondria were isolated and evaluated by high-resolution respirometry. Low cardiac output, hypotension, oliguria and severe reductions in mixed-venous and hepatic O₂ saturations were evident in cardiogenic shock. The sublingual total and perfused vessel densities were fully preserved throughout the experiments. Cardiac mitochondrial respiration was unaltered, whereas state 2, 3 and 4 respiration of renal and hepatic mitochondria were increased in cardiogenic shock. Mitochondrial viability (RCR; state 3/state 4) and efficiency (ADP/O ratio) were unaffected. Our study demonstrates that the microcirculation is preserved in a porcine model of untreated cardiogenic shock despite vital organ hypoperfusion. Renal and hepatic mitochondrial respiration is upregulated, possibly through demand-related adaptations, and the endogenous shock response is thus compensatory and protective, even after several hours of global hypoperfusion.     

Levels of Cry1Ac1 protein in herbivorous and predatory arthropods in fields of Bacillus thuringiensis cabbage

To investigate the extent of exposure and routes of Cry1Ac1 protein through the food chain, we collected Bt cabbage leaves and arthropods that occurred in the field during two trials. Protein levels in the transgenic leaves were significantly higher during the early stages of plant growth, ranging from 209.1 to 553.6?ng?g^?1 in spring and from 208.2 to 402.8?ng?g^?1 in autumn. Enzyme-linked immunosorbent assays were used to measure protein levels in the arthropods. Among the 16 taxa collected in the field, Cry1Ac1 was detected in the bodies of 10. Concentrations were higher in lepidopteran larvae than in the other taxa. In particular, we found a significant correlation between Cry1Ac1 protein levels in cabbage leaves and in Pieris rapae and Mamestra brassicae. Furthermore, this protein was detected in five out of nine taxa of predators (spiders and coleopterans) and parasitoids. These results will be useful as we identify the arthropods that are directly or indirectly exposed to Bt toxin within the food web and the degree to which they are exposed during the cultivation of Bt cabbage.     

In vivo sequence diversity of the protease of human immunodeficiency virus type 1: presence of protease inhibitor-resistant variants in untreated subjects.

We have evaluated the sequence diversity of the protease human immunodeficiency virus type 1 in vivo. Our analysis of 246 protease coding domain sequences obtained from 12 subjects indicates that amino acid substitutions predicted to give rise to protease inhibitor resistance may be present in patients who have not received protease inhibitors. In addition, we demonstrated that amino acid residues directly involved in enzyme-substrate interactions may be varied in infected individuals. Several of these substitutions occurred in combination either more or less frequently than would be expected if their appearance was independent, suggesting that one substitution may compensate for the effects of another. Taken together, our analysis indicates that the human immunodeficiency virus type 1 protease has flexibility sufficient to vary critical subsites in vivo, thereby retaining enzyme function and viral pathogenicity.     

Stimulation of adventitious rooting of Taxus species by thiamine

Summary Results obtained from using root inducing compounds on Taxus species cuttings suggested that rooting could be significantly enhanced by the presence of thiamine. This observation was verified using a root inducing solution containing a set concentration of IBA (0.2%), NAA (0.1%), and supplemented with various concentrations of thiamine. The best rooting response for Taxus cuspidata stem cuttings was found using this solution supplemented with 0.08% thiamine. Rooted cuttings were easily established and developed into vigorous plants. In addition, Taxus brevifolia shoots obtained from tissue cultures via in vitro organogenesis also responded favorably to this 0.08% thiamine supplemented rooting solution.     

A human SHC-related sequence maps to chromosome 17, the SHC gene maps to chromosome 1

The SHC gene encodes a protein that is thought to act as an adapter in many signal transduction pathways; the SHC protein probably facilitates the activation of RAS proteins in response to a variety of factors. We have mapped the human SHC gene and have identified a new SHC-related sequence. We have sequenced the region corresponding to the SHC 3 UTR from both loci and have mapped cosmids by fluorescence in situ hybridization. The human SHC gene maps to the proximal long arm of chromosome 1 and the SHC-related sequence maps to the proximal long arm of chromosome 17. A number of cancers have been positioned in the proximal long arm of chromosome 1; this is of interest given the oncogenic potential of the SHC protein.     

A functional genetic marker for apple red skin coloration across different environments

The red skin color desired by most apple consumers is not easy to achieve in warm climates, as the expression of MYB10, which regulates red pigmentation in apple, is influenced negatively by high temperatures. We describe the development and validation of a genetic marker for red skin coloration that effectively predicts color in a warm summer environment in Spain, as well as more temperate climates in New Zealand and Italy. Following the determination of a major-effect quantitative trait locus (QTL) controlling red skin coloration on linkage group (LG)9, using four segregating populations grown in New Zealand, and screened using the IRSC apple 8-K single-nucleotide polymorphism (SNP) array, the most significant SNP marker (ss475879531) was transformed into a marker suitable for use in a real-time PCR assay. This marker was validated using five apple seedling populations growing in a warm summer environment in Spain, demonstrating that the marker system efficiently predicts red skin coloration and can be used for marker assisted selection, even under conditions considered adverse for skin color development.     

The Disability Rate of 5-Year Post-Stroke and Its Correlation Factors: A National Survey in China

Few studies on long-term functional outcome have been conducted in post-stroke patients in China. The objective of this study was to conduct a nationwide survey in China to investigate the 5-year prevalence of post-stroke disability and its correlation factors. A total of 893 patients with ischemic stroke were included. Demographic, clinical and neuro-imaging information were collected with standardized instruments that assessed stroke severity, depression, cognitive impairment, stroke recurrence and physical disability. Disability was assessed with the modified Ranking Score (mRS), of which a cutoff score ≥2 indicates disability. Statistical analysis included chi-square tests, two independent samples t-tests, Mann-Whitney U test and multiple logistic regression analysis. The frequency of disability in this study population was 45%. Multivariate analyses revealed that older age, lower education level, previous history of stroke, stroke severity at admission, depression, cognitive impairment at 3 months, and stroke recurrence within 5 years follow up were all significantly associated with post-stroke disability. The disability rate in 5-year post-stroke was high in Chinese patients. Treatment of depression, secondary prevention of stroke and rehabilitation may benefit disabled patients with stroke in China.