Polyplex-embedding in polyelectrolyte multilayers for gene delivery

In this work, incorporation of plasmid DNA, pre-complexed with PEI, into polyelectrolyte multilayers has been studied to further develop platforms for local gene delivery. Polyplex embedding in synthetic and naturally degradable architectures was efficient for transfection of human hepato-cellular carcinoma cells.     

Preference and performance of the hyperparasitoid Syrphophagus aphidivorus (Hymenoptera: Encyrtidae): fitness consequences of selecting hosts in live aphids or aphid mummies

Abstract.  1. Theoretical models predict that ovipositional decisions of parasitoid females should lead to the selection of the most profitable host for parasitoid development. Most parasitoid species have evolved specific adaptations to exploit a single host stage. However, females of the aphid hyperparasitoid Syrphophagous aphidivorus (Mayr) (Hymenoptera: Encyrtidae) display a unique and atypical oviposition behaviour by attacking either primary parasitoid larvae in live aphids, or parasitoid pupae in dead, mummified aphids.
2. In the laboratory, the correlation between host suitability and host preference of S. aphidivorus on the host Aphidius nigripes Ashmead parasitising the aphid Macrosiphum euphorbiae (Thomas) was investigated.
3. The relative suitability of the two host stages was determined by measuring hyperparasitoid fitness parameters (survival, development time, fecundity, sex ratio, and adult size of progeny), and calculating the intrinsic rate of population increase ( r _m). Host preference by S. aphidivorus females and the influence of aphid defence behaviour on host selection was also examined.
4. Hyperparasitoid offspring performance was highest when developing from hosts in aphid mummies and females consistently preferred this host to hosts in parasitised aphids. Although aphid defensive behaviour may influence host selection, it was not a determining factor. Ecological and evolutionary processes that might have led to dual oviposition behaviour in S. aphidivorus are discussed.     

Human bone marrow stromal cells express an osteoblastic phenotype in culture

Summary This study reports the selection and characterization of osteogenic precursors from human bone marrow which were isolated by two “clonings” and successive subculturing. These cell lines express alkaline phosphatase activity. Gel electrophoresis of [³H]-proline labeled cultures showed that the cloned cells produce only type I collagen. They synthetize osteocalcin and osteonectin. They respond to 1,25 dihydroxy vitamin D₃ by increasing osteocalcin synthesis and secretion, and to parathyroid hormone by increasing cyclic AMP synthesis. After the third subculture in the absence of β-glycerophosphate, these cell lines formed lots of clusters which exhibit high alkaline phosphatase activity and positive von Kossa staining. X-ray energy spectrum shows that these cells are surrounded by “budding” structures containing calcium and phosphorus with a ratio Ca:P identical to those of pure hydroxyapatite. This process was associated with⁴⁵Ca uptake into the cells. All these data support the selection of osteogenic cells which may be of considerable clinical importance.     

Mitogenic activity of Neisseria gonorrhoeae surface antigens in mouse splenic lymphocyte culture.

The mitogenic effects of Neisseria gonorrhoeae endotoxin, fractionated envelope componenents, and intact cells were examined on unsensitized mouse splenic lymphocytes in vitro. The stimulatory effect of these substances was measured by increased [3H]thymidine incorporation in spleen cell cultures. Intact cells, purified lipopolysaccharide (LPS), and cell envelope preparations were highly stimulatory and the stimulation index was dose dependent. Fractionated components of the envelope demonstrated variable stimulation when tested at identical LPS concentrations, reflecting the mitogenic activity of the protein moieties. The stimulatory dose responses for purified N. gonorrhoeae and Escherichia coli LPS were compared and mitogenicity was higher with gonococcal LPS at all concentrations tested. Alkaline detoxification or succinylation of N. gonorrhoeae LPS results in loss of ability to induce blast transformation. The mitogenicity of cell-surface components of N. gonorrhoeae is discussed in terms of LPS and protein content.     

Urinary excretion of mandelic, phenylglyoxylic, and specific mercapturic acids in rats exposed repeatedly by inhalation to various concentrations of styrene vapors

Adult male Sprague-Dawley rats were exposed by inhalation to various concentrations of styrene vapors (25, 50, 100, or 200 ppm) 6 h/day, 5 days/week, for 4 consecutive weeks. The concentrations were varied from day to day according to a random pattern allowing treated animals to be exposed five times to each concentration of styrene. Each day, the following urinary metabolites were analysed from samples collected during exposure (0-6 h) and after exposure (6-24 h): mandelic acid; phenylglyoxylic acid; and two mercapturic acids, N-acetyl-S-(1-phenyl-2-hydroxyethyl)-L-cysteine (M1) and N-acetyl-S-(2-phenyl-2-hydroxyethyl)-L-cysteine (M2). Various parameters of renal toxicity and hepatic microsomal and cytosolic enzyme activities were also measured. The results show that there is a very good relationship between the excretion of all four styrene metabolites and the degree of daily exposure to styrene over the entire period of urine collection, with correlation coefficients ranging from 0.82 to 0.98. The correlation was poor for mandelic acid during the 0-6 h period. There was no evidence that repeated exposure to styrene caused renal toxicity, nor induced hepatic microsomal enzyme activities; cytosolic glutathione S-transferase activity was increased moderately by 1.5 times. Thus, under conditions of exposure to styrene likely to be found in the workplace, all four metabolites measured were good indicators of styrene exposure throughout the length of the experiment. Since mercapturic acids result from the conjugation of styrene oxide with glutathione, the data suggest that measurement of these metabolites offers the possibility to monitor internal exposure to a toxic electrophilic compound more directly.     

Histochemical demonstration of an increase in acetylcholinesterase in established lines of human and mouse neuroblastomas by nerve growth factor.

Cells of three established lines of human neuroblastoma and an established line of C1300 mouse neuroblastoma were grown in control medium or in experimental medium containing mouse nerve growth factor (NGF). Cultures were stained histochemically for acetylcholinesterase (AChE) during log growth and at confluency. Human neuroblastoma cells grown in medium containing NGF were morphologically more differentiated and they were stained much more intensely for AChE during both phases of growth than were cells in control cultures. The enzyme was distributed over cell bodies and neurites. Neuroblastoma cells of the mouse line were not stimulated to form neurites by NGF, but they were more intensely stained for acetylcholinesterase than cells grown in control medium. These observations support earlier findings that NGF stimulates differentiation of human and mouse neuroblastoma cells in vitro.     

Effects of Pieris host species on life history parameters in a solitary specialist and gregarious generalist parasitoid (Cotesia species)

Host specificity and host selection by insect parasitoids are hypothesized to be correlated with suitability of the hosts for parasitoid development. The present study investigates the correlation between host suitability and earlier studied host-finding behaviour of two closely related braconid larval parasitoid species, the generalist Cotesia glomerata (L.) and the specialist C. rubecula (Marshall) (Hymenoptera: Braconidae). We compared the capability of both parasitoid species to parasitize and develop in three Pieris host species, i.e. P. brassicae (L.), P. rapae (L.) and P. napi (L.) (Lepidoptera: Pieridae). In laboratory experiments, we measured the effect of host species on fitness parameters such as survival, development, sex ratio and size of parasitoid progeny. The results show that C. glomerata is capable of developing in the three host species, with significant differences in parasitoid survival, clutch size and adult weight among Pieris species. The host range for development was more restricted for C. rubecula. Although C. rubecula is physiologically able to develop in P. brassicae larvae, parasitoid fitness is negatively affected by this host species, compared to its most regular host, P. rapae. A comparison of the present data on host suitability with earlier studies on host-searching behaviour suggests that the host-foraging behaviour of both parasitoid species not only leads to selection of the most suitable host species for parasitoid development, but also plays a significant role in shaping parasitoid host range.     

(3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone: A potent,selective, orally active dipeptidyl peptidase IV inhibitor

A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC₅₀ = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.