Targeted delivery of antisense oligonucleotides to pancreatic ß-cells.

Antisense oligonucleotide (ASO) silencing of the expression of disease-associated genes is an attractive novel therapeutic approach, but treatments are limited by the ability to deliver ASOs to cells and tissues. Following systemic administration, ASOs preferentially accumulate in liver and kidney. Among the cell types refractory to ASO uptake is the pancreatic insulin-secreting ß-cell. Here, we show that conjugation of ASOs to a ligand of the glucagon-like peptide-1 receptor (GLP1R) can productively deliver ASO cargo to pancreatic ß-cells both in vitro and in vivo. Ligand-conjugated ASOs silenced target genes in pancreatic islets at doses that did not affect target gene expression in liver or other tissues, indicating enhanced tissue and cell type specificity. This finding has potential to broaden the use of ASO technology, opening up novel therapeutic opportunities, and presents an innovative approach for targeted delivery of ASOs to additional cell types.

Column asymmetric catalysis for beta-lactam synthesis.

[structure] A catalytic asymmetric reaction process was designed involving the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, yielding pure product after crystallization with exceptional enantio- and diastereoselectivity.

Nucleophilic metal complexes as acylation catalysts: solvent-dependent "switch" mechanisms leading to the first catalyzed Staudinger reaction.

[formula: see text] Catalytic acylation using complex transition metal salts MCo(CO)4 is demonstrated. Surprisingly, a solvent-dependent mechanistic "switch" results in a Lewis acid-based acylation mechanism in nonpolar media and a nucleophilic mechanism in polar organic media. These observations lead to the first example of a catalyzed Staudinger reaction to form beta-lactams.

Complications of plate fixation of forearm fractures.

Sixty-four adult patients (87 diaphyseal forearm fractures) were treated by plating. Thirty-nine percent of the fractures were classified as single bone fractures (16% radius, 23% ulna); 43% were both radial and ulnar fractures, and 19% were Galeazzi or Monteggia fracture-dislocations. A major complication occurred in 18 (28%) patients. Nonunion occurred in six patients: three of 18 bones treated with four screws (17%), but only three of 69 bones fixed with five or more screws (4.3%), a nonunion rate four times higher for bones plated with four screws. Screws loosened in three fractures, all involving the ulna. Radioulnar synostosis occurred in seven forearms, and in five of these the forearm injuries were associated with multiple system trauma involving head injury. Two patients had osteomyelitis. Both were victims of massive crush injury and delayed internal fixation, and both required removal of the implant; but eventually the fractures healed. Plate fixation of forearm fractures can have a high complication rate. Meticulous attention to surgical technique and the use of plates long enough to provide secure fixation can not be overemphasized. An increased incidence of synostosis in polytrauma, head-injured patients was noteworthy.

Transport of 1-microm latex particles in pseudomonas aeruginosa biofilms.

Fluorescent latex microbeads added to a Pseudomonas aeruginosa biofilm as tracers of particle movement penetrated the biofilm and remained in it much longer than predicted by a model of advective displacement due to cell growth. Beads with a nominal diameter of 1 mum that were added in the bulk fluid became distributed throughout the biofilm depth. Some microbeads penetrated to the substratum within the 24-h bead addition period. The biofilms had a mean thickness of approximately 34 mum but have been previously shown to be quite rough. Measured rates of bead release from the biofilm corresponded to first order time coefficients of 0.01-0.03 h(-1). These bead release rates were approximately an order of magnitude less than the predicted time scale of advective transport, which is just the experimentally measured specific cellular growth rate of 0.15 h(-1). Computer simulations of bead transport using the biofilm model BIOSIM were compared with bead release rate data and with bead position distributions within the biofilm as determined by microscopic examination of thin cross sections of embedded biofilm. The model predicted much faster release of beads from the biofilm than actually occurred. It is hypothesized that both the ability of beads to penetrate the biofilm and the unexpectedly low advective displacement velocity of particles in the biofilm were due to the rough nature of the biofilm.

Quantitative observations of heterogeneities in Pseudomonas aeruginosa biofilms.

Heterogeneity in a Pseudomonas aeruginosa biofilm was quantified by measuring distributions of thickness in biofilm samples and a distribution of particle sizes in effluent samples. The mean steady-state thickness was approximately 33 microns, but individual measurements ranged from 13.3 to 60.0 microns. Particles exceeding 100 microns3 were observed in the reactor effluent. The results reveal a rough biofilm surface and indicate that most biomass detaches in the form of multicellular particles.