Noncanonical conformation of nucleic acids: structure with slipped-loops, occurring in DNA oligonucleotides

A HPLC method was developed and validated for the quantitation of 9-cis-retinoic acid (ALRT1057) and its major metabolite, 4-oxo-9-cis-retinoic acid (LG100182) in human plasma. Samples were buffered and extracted with methyl-tert-butyl-ether. The analytes and an I.S. were separated on a C18 HPLC column using a shallow gradient of 70-89% organic solvent. The analytes were quantitated by UV detection at 348 nm. Selectivity against endogenous compounds and potential metabolites (retinol, all trans-, 13-cis-, and 4-hydroxy-9-cis-retinoic acid) was demonstrated. The run time was 29 min. The standard curve was linear from 2.5 to 450 ng ml-1. Interassay precision for both analytes in quality control samples was less than 5.0% RSD. Accuracy was within 11.0% RE for both compounds. Analyte stability during sample storage, extraction processing, and chromatography was established. Method ruggedness was tested by two analysts and on two HPLC systems. This method has been applied to the quantitation of clinical samples.     

CVT-313, a specific and potent inhibitor of CDK2 that prevents neointimal proliferation

The activity of cyclin-dependent kinase 2 (CDK2) is essential for progression of cells from G1 to the S phase of the mammalian cell cycle. CVT-313 is a potent CDK2 inhibitor, which was identified from a purine analog library with an IC50 of 0.5 microM in vitro. Inhibition was competitive with respect to ATP (Ki = 95 nM), and selective CVT-313 had no effect on other, nonrelated ATP-dependent serine/threonine kinases. When added to CDK1 or CDK4, a 8.5- and 430-fold higher concentration of CVT-313 was required for half-maximal inhibition of the enzyme activity. In cells exposed to CVT-313, hyperphosphorylation of the retinoblastoma gene product was inhibited, and progression through the cell cycle was arrested at the G1/S boundary. The growth of mouse, rat, and human cells in culture was also inhibited by CVT-313 with the IC50 for growth arrest ranging from 1.25 to 20 microM. To evaluate the effects of CVT-313 in vivo, we tested this agent in a rat carotid artery model of restenosis. A brief intraluminal exposure of CVT-313 to a denuded rat carotid artery resulted in more than 80% inhibition of neointima formation. These observations suggest that CVT-313 is a promising candidate for evaluation in other disease models related to aberrant cell proliferation.     

Integrin receptor signaling: the propagation of an alpha-helix model

Improper assessment and treatment of asthma attacks have been identified as causes of increased morbidity and mortality: several pneumological societies have therefore created and published guidelines for facilitating decision making and for preventing unnecessary failures of therapy. The objective of this study was to examine emergency department compliance with such guidelines in our hospital, comparing the performance of pneumologists and other specialists. We reviewed the records of 117 patients treated for acute asthma attacks in 1994 (87 women and 30 men, mean age 46 years); 37 patients were treated by pneumologists and 80 by other specialists. The two physician groups differed significantly with respect to initial assessment of severity, particularly in the recording of vital signs (p < 0.05) and in the examination of some signs such as the use of accessory musculature (38% versus 10%, for pneumologists and other specialists, respectively) or the presence of cyanosis (81% versus 55%). Other factors associated with risk of death were noted only occasionally. Peak flow meters were used with only 5 patients, all examined by pneumologists; on the other hand, arterial blood samples for gasometric measurements were taken from 97%, although only 24% met the criteria stipulated in the guidelines. Treatment evaluated against the guidelines was incorrect in 24%, with no significant differences between pneumologists and other specialists. We conclude that: 1) the emergency clinical assessment and treatment of patients presenting with acute asthma attack is inadequate for a large proportion of patients, as the recommendations of consensual guidelines are habitually ignored, and 2) although there are differences in the management of these patients by pneumologists and other emergency room specialists, the former do not generally do a better job of following the guidelines.