CLASS study

Given experimental measurements with p= 123.4 and a = 12.9, draw the entire probability distribution curve for the population of all experimental measurements in the class studied. 

The Effect of Ionic Strength on an Equilibrium Constant (A Class Study). In J. A. Bell, ed. Chemical Principles in Practice. Addison-Wesley Reading, MA, 1967. 

Two large trials, the Vioxx Gastrointestinal Outcomes Research (VIGOR) study and the Celecoxib Long-term Arthritis Safety Study (CLASS), compared selective COX-2 inhibitors and traditional, non-selective NSAID therapy in terms of their ability to prevent clinical PUD (i.e., symptomatic ulcers and ulcer complications). VIGOR (9-month median follow-up) demonstrated that rofecoxib (50 mg daily) therapy was significantly more efficacious than naproxen.28 The CLASS study (6-month median follow-up) found that high-dose celecoxib (400 mg twice daily) was superior to non-selective NSAID therapy (either ibuprofen 800 mg three times daily or diclofenac 75 mg twice daily).29... 

Silverstein FE, Faich G, Goldstein JL, et al. Gastrointestinal toxicity with celecoxib vs nonsteroidal anti-inflammatory drugs for osteoarthritis and rheumatoid arthritis The CLASS study A randomized, controlled trial. Celecoxib Long-term Arthritis Safety Study. JAMA 2000 284 1247-1255. 

More in detail, classification techniques are able to determine to which class a sample more probably belongs, among a number of predefined classes. They work by building a delimiter between the classes. Then, each new object is always assigned to the category to which it more probably belongs, even in the case of objects which are not pertinent to any class studied. 

The CLASS study published in fAMA in 2000 appeared to confirm the gastrointestinal protective effects of celecoxib (Celebrex ) over traditional NSAIDs after six months of treatment (Silverstein et al. 2000). However, material on the website of the FDA revealed a number of discrepancies between the data as published in fAMA and those submitted to the FDA. The published trial actually combined the results of two trials, one that continued for twelve months and the second which ran for 16 months. At 12-16 months there was no difference in gastrointestinal adverse effects between the celecoxib and traditional NSAID groups (Hrachovec and Mora 2001 Wright et al. 2001). 

K. M. Verburg, and G. S. Geis. 2000. Gastrointestinal Toxicity with Celecoxib vs Nonsteroidal Anti-inflammatory Drugs for Osteoarthritis and Rheumatoid Arthritis The CLASS Study A Randomized Controlled Trial. JAMA 284 1247-1255. 

Some real matrix classes, studied in subsection (F) below, however, have only real eigenvalues and corresponding real eigenvectors. The complication with complex eigenvalues and eigenvectors is caused by the Fundamental Theorem of Algebra which states that all the roots of both real and complex polynomials can only be found in the complex plane C. 

To obtain a common reference frame for SARI analysis, raw scores are converted into z-scores using the sample mean and standard deviation of the scores of a reference set of different activity classes. For initial SARI calculations discussed herein, a set of 16 representative compound classes was used as a reference set (Table 4.3). Using larger reference sets had no significant influence on the results of the analysis. Thus, the classes studied here were sufficient to calculate statistically sound z-scores. Therefore, the mean and... 

This route of self-development was a natural and unavoidable occupation for the immature science of organic chemistry. Now, when millions of organic compounds have already been described and their basic classes studied rather thoroughly, such a synthesis for the sake of synthesis may seem extravagant. It is a most difficult dilemma to ascertain whether it is actually worthwhile to appropriate resources from a goal-orientated investigation to the synthesis of... 

Shumway s A Day in Ancient Rome. With 59 illustrations. Should find a place as a supplementary reader in every high-school class studying Cicero, Horace, Tacitus, etc. 96 pages. Paper, 30 cents cloth, 75 cents. 

Considerable work on electron exchange reactions of cations of oxidation state 4-3, +4 has been done. In only one of the systems of this class studied are the ions involved (reactants and products) actually of charge 4-3 and 4-4. Keenan (66) reports the rate of electron exchange between Pu+++ and Pu + to be given by ... 

Juni P, Rutjes AWS, Dieppe P. Pharmacia addresses June 1 editorial regarding CLASS study authors response. BMJ 2002 324 1287-8. 

Recovery of phospholipids, as well as the various neutral lipids, is obtained with good yields on aminopropyl tubes. Hence, Kaluzny s procedure was shown to recover up to 100% of all the lipid classes studied, giving better results than the TLC procedure [6]. This latter procedure has been extensively used by many workers to separate lipid mixtures from different origins. It has been slightly modified and adapted for particular use with poorer fractionation of lipid samples... 

Drug class Study drug Control Total cases... 

To study effects on clinically important GI complications with celecoxib, the CLASS study used celecoxib (400 mg twice daily, or twice the highest FDA-approved dose) compared to diclofenac and ibuprofen at standard dose. Celecoxib use was reported to be associated with a reduced incidence for the combined end point of symptomatic ulcers and ulcer complications (perforations, gastric outlet obstruction, or bleeding). Some subjects also used aspirin for car-dioprotection, but there is concern that GI safety of COX-2 inhibitors is blunted with use of concomitant aspirin (even 30 mg of aspirin can suppress gastric prostaglandin prodnction)." For patients taking aspirin and celecoxib, nicer complications were higher than with celecoxib only, but lower than with traditional NSAIDs. 

Concerns have been raised by the FDA and others with regard to the CLASS study design and whether the published results, based on 6 months, clearly reflect the overall GI safety profile, as these patients were actually followed for a longer time period. The... 

At least some of these criteria are so highly correlated with carcinogenicity that they have been developed as short-term tests. One good approach to improve the use of the functional criteria is to carry out a systematic chemical class-by-chemical class study of the correlation between the particular functional criterion in question and carcinogenicity. Not all chemical classes are expected to demonstrate a certain functional criterion endpoint. The class-specific approach should enhance the usefulness of the functional criteria approach in predicting potential carcinogenicity. 

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