Pathogenesis of diabetic macular oedema

Hyperglycaemia causes breakdown of the blood retina barrier leading to formation of macular oedema and consecutive visual loss. Three major mechanisms are involved in barrier breakdown: increased paracellular permeability of vascular endothelium due to disruption of cell junctions, loss of endothelial cell layer integrity due to cell destruction, and increased transcellular transport through the endothelium. This review focuses on the molecular basis of these mechanisms and discusses the role of cytokines and cellular interactions in blood retina barrier breakdown.     

Phase I/II combined chemoimmunotherapy with carcinoembryonic antigen-derived HLA-A2-restricted CAP-1 peptide and irinotecan, 5-fluorouracil, and leucovorin in patients with primary metastatic colorectal cancer.

PURPOSE: We conducted a phase I/II randomized trial to evaluate the clinical and immunologic effect of chemotherapy combined with vaccination in primary metastatic colorectal cancer patients with a carcinoembryonic antigen-derived peptide in the setting of adjuvants granulocyte macrophage colony-stimulating factor, CpG-containing DNA molecules (dSLIM), and dendritic cells. EXPERIMENTAL DESIGN: HLA-A2-positive patients with confirmed newly diagnosed metastatic colorectal cancer and elevated serum carcinoembryonic antigen (CEA) were randomized to receive three cycles of standard chemotherapy (irinotecan/high-dose 5-fluorouracil/leucovorin) and vaccinations with CEA-derived CAP-1 peptide admixed with different adjuvants [CAP-1/granulocyte macrophage colony-stimulating factor/interleukin-2 (IL-2), CAP-1/dSLIM/IL-2, and CAP-1/IL-2]. After completion of chemotherapy, patients received weekly vaccinations until progression of disease. Immune assessment was done at baseline and after three cycles of combined chemoimmunotherapy. HLA-A2 tetramers complexed with the peptides CAP-1, human T-cell lymphotrophic virus type I TAX, cytomegalovirus (CMV) pp65, and EBV BMLF-1 were used for phenotypic immune assessment. IFN-gamma intracellular cytokine assays were done to evaluate CTL reactivity. RESULTS: Seventeen metastatic patients were recruited, of whom 12 completed three cycles. Therapy resulted in five complete response, one partial response, five stable disease, and six progressive disease. Six grade 1 local skin reactions and one mild systemic reaction to vaccination treatment were observed. Overall survival after a median observation time of 29 months was 17 months with a survival rate of 35% (6 of 17) at that time. Eight patients (47%) showed elevation of CAP-1-specific CTLs. Neither of the adjuvants provided superiority in eliciting CAP-1-specific immune responses. During three cycles of chemotherapy, EBV/CMV recall antigen-specific CD8+ cells decreased by an average 14%. CONCLUSIONS: The presented chemoimmunotherapy is a feasible and safe combination therapy with clinical and immunologic efficacy. Despite concurrent chemotherapy, increases in CAP-1-specific T cells were observed in 47% of patients after vaccination.     

The ability of biofilm formation does not influence virulence of Staphylococcus aureus and host response in a mouse tissue cage infection model

The virulence of Staphylococcus aureus Sa113 (SA113) and an isogenic ica deletion mutant (ica-), deficient in the production of polysaccharide intercellular adhesin (PIA), which is crucial for biofilm formation, was compared in a mouse tissue cage infection model. The minimal infective doses for the induction of persistent tissue infections in C57BL/6 mice were 10(3) CFU for both SA113 and the ica- mutant. Bacterial growth, initial adherence to surfaces within the implants and the course of inflammation including growth-dependent host TNF and MIP-2 release, influx of phagocytes and an accumulation of dead leukocytes were similar as well. Since SA113 expressed PIA in vivo, we could demonstrate that PIA and the lack of biofilm formation did not influence the capacity of S. aureus to induce persistent infections and did not modulate host responses in the mouse tissue cage model.     

L-selegiline potentiates the cellular poly(ADP-ribosyl)ation response to ionizing radiation

DNA strand breaks induced by alkylating agents, oxidants, or ionizing radiation trigger the covalent modification of nuclear proteins with poly(ADP-ribose), which is catalyzed for the most part by poly(ADP-ribose) polymerase-1 and plays a role in DNA base-excision repair. Poly(ADP-ribosyl)ation capacity of mononuclear blood cells correlates positively with life span of mammalian species. Here, we show that l-selegiline, an anti-Parkinson drug with neuroprotective activity and life span-extending effect in laboratory animals, can potentiate gamma-radiation-induced poly(ADP-ribose) formation in intact cells. COR4 hamster cells were incubated with l-selegiline (50 nM) for various time periods, followed by gamma-irradiation (45 Gy). Quantification of cellular poly(ADP-ribose) levels at 10 min after starting the irradiation revealed significant increases (up to 1.8-fold) in cells preincubated with the drug for 8 h to 7 days compared with drug-free irradiated controls. There was no selegiline-induced change in poly(ADP-ribose) levels of unirradiated cells nor in basal or radiation-induced DNA strand breaks, respectively. Surprisingly, poly(ADP-ribose) polymerase-1 protein was down-regulated by l-selegiline treatment. Addition of l-selegiline to purified poly(ADP-ribose) polymerase-1 did not alter enzymatic activity. In conclusion, the results of the present study identify a novel intervention to potentiate the cellular poly(ADP-ribosyl)ation response. We hypothesize that the effect of l-selegiline is due to modulation of accessory proteins regulating poly(ADP-ribose) polymerase-1 activity and that increased cellular poly- (ADP-ribosyl)ation capacity may contribute to the neuroprotective potential and/or life span extension afforded by l-selegiline.     

Die Insulinresistenz beim polyzystischen Ovar-Syndrom

With a prevalence of 5-10% the polycystic ovary syndrome (PCOS) is a common disorder of premenopausal women. According to prospective studies abnormal glucose tolerance and diabetes mellitus present in about 10.0% and 35.0% of adult women with PCOS, respectively. PCOS patients have a higher prevalence of cardiovascular risk factors such as hypertension and dyslipidaemia. The rate of spontaneous abortions as well as the risk of developing gestational diabetes is increased in PCOS. Therefore, PCOS is not only a reproductive problem, but a complex endocrine disease with important health implications. The role of glucose metabolism in PCOS, the health consequences and possible interventions are reviewed in this article.     

Comparative permeability and diffusion kinetics of cyclosporine A liposomes and propylene glycol solution from human lung tissue into human blood ex vivo

Aerolized cyclosporine A (CsA) has been successfully used for prevention of organ rejection in lung transplant recipients. Various formulations of CsA are available and so far no direct comparison of their pharmacokinetics has been performed. Since clinical studies are elaborate, we sought a way to predict the kinetic behaviour of a propylene glycol solution of CsA (CsA-PG) and a liposomal formulation (L-CsA). The permeability across the human bronchial cell line Calu-3 revealed low permeability for CsA with the apparent permeability for CsA-PG being twice as high as for L-CsA. Employing a previously described dialysis model, the diffusion of CsA from human lung tissue into human blood was determined ex vivo. Consistent with the cell culture model results, we observed that the degree and rate of drug transfer into human blood was more pronounced for CsA-PG than for L-CsA with the area under the curve (AUC) of CsA-PG being about 1.6 times higher than for the L-CsA formulation. The diffusion rate was more than 50% higher from CsA-PG than from the liposomes. To conclude, both model systems consistently revealed that L-CsA displayed clearly a prolonged release effect and favourable longer tissue retention than CsA-PG.     

Influence of the stationary phase on the stability of thalidomide and comparison of different methods for the quantification of thalidomide in tablets using high-temperature liquid chromatography

In this paper, three different HPLC methods for the quantification of thalidomide in tablets were developed and compared. The comparison of a conventional method at 30 degrees C with two high-temperature methods at 180 degrees C showed equal results. Using high-temperature HPLC (HT-HPLC), faster analysis times could be achieved. We have also focused on analyte stability and could show that the stationary phase has a pronounced effect on the on-column degradation of thalidomide at high temperatures. Virtually no degradation occurs if a polystyrene divinylbenzene column is used, whereas thalidomide is completely degraded at 180 degrees C when a carbon clad zirconium dioxide column is used.     

Evaluation of genus-specific and species-specific real-time PCR assays for the identification of Brucella spp.

BACKGROUND: The identification of Brucella isolates using conventional microbiological techniques is time-consuming and hazardous. We therefore assessed the performance of real-time PCR assays for the identification of members of the genus Brucella to the genus and species level. METHODS: We evaluated an in-house developed assay and various previously published real-time PCR assays targeting bcsp31, per, IS711, alkB/IS711 and BMEI1162/IS711 using 248 Brucella strains representing the biotypes of all species and a large panel of clinically relevant, phylogenetically related and serologically cross-reacting bacteria. RESULTS: No misidentification was observed. However, several biotypes of Brucella abortus and Brucella suis were not detected with some of the published assays. The limit of detection varied widely among the assays (16-1600 fg) demonstrating that some assays should not be applied to clinical samples but may help to identify colony material. CONCLUSIONS: In summary, most of the assays revealed low detection limits and proved to be highly selective for the detection of the genus Brucella and the species that are most relevant for humans. Assays targeting the bcsp31 gene can be recommended to screen for Brucella. Species-specific assays should be consecutively applied confirming the primary diagnosis by a second gene target.