Agent criteria

A multinational, non-comparative study was conducted to examine proven or probable Aspergillus species infection in a wide variety of patients. The study employed an open-label design utilising micafungin alone or in combination with another systemic antifungal agent. Criteria for IA and therapeutic response were judged by an independent panel. 

Major factors influencing design (Figure 2) were identified as regulatory criteria, operational capabilities, current state of the art, and agent criteria. 

Several electrophiles, such as acetic anhydride, nitric acid or alternative nitrating agents, such as ammonium nitrate in trifluoroacetic anhydride (41), or sodium hypochlorite, react at N-1, which is followed by reaction at N-3 under suitable conditions. In the case of acetic anhydride, the reaction can take place exclusively at N-3 if N-1 is hindered this fact has served as a criterion for studying the stereochemistry of 5-spirohydantoin derivatives (42,43). 

Paroxetine is the most potent inhibitor of 5-HT reuptake but, in terms of distinguishing one compound from another, their preferential selectivity for inhibition of 5-HT rather than noradrenaline reuptake is the key criterion. Citalopram is by far the most selective in vitro (1500-3000-fold) and fluoxetine, the most frequently prescribed SSRI in the UK, is the least selective of all these agents (see Stanford 1999). In fact, it is worth questioning whether fluoxetine is a true SSRI at all. 

One response may be that it is possible to manage the red tide at the source of the bloom (8) or that there is no need to manage a red tide over vast areas, merely in localized ones that are of special interest. The point is moot until a suitable control agent is available. A considerable number of chemicals have been reviewed for possible red tide control substances, (9), and in retrospect this type of research is subject to ultimate failure because the first criterion of a successful control agent (chemical or biological) has not been considered. 

Table I. It is probable that all the indicated yields can be improved. However, using these data as a criterion, it appears that the chloral can be replaced by its hydrate or alcoholate and that a moderate excess of fluorobenzene favors the reaction. There is one report that aluminum chloride brings about this condensation (34), but here, as with DDT, the choice condensing agents are concentrated sulfuric acid (with or without the addition of oleum), and chlorostflfonic acid (84). A moderate temperature and prolonged stirring, which must also be vigorous, increase the yield.

Evaluation of Results. At least two independent assays are carried out for each test article. The criterion for positive response is a reproducible and statistically significant result at any concentration for any strain. When positive results are obtained, the test is repeated, using the strain(s) and concentration range with which the initial positive results were observed. This range may be quite narrow for toxic agents. 

Toxicity tests are necessary tools to evaluate the concentration and duration of exposure of a chemical required to produce certain adverse effects. Molecular processes directly affected by the exposure to the chemical agent are the most liable criterions. Nevertheless, these effects are difficult to detect in aquatic toxicology because the processes are generally not well understood [72], Alternatively, other end points which fulfil the necessary requirements, namely the need to be unequivocal, relevant, easy to observe, describe and measure, biologically significant and repeatable, are used. These include measures of mortality, which is frequently employed in the early evaluation of the toxicity of a pollutant in acute toxicity tests. This criterion allows comparison of toxicity exerted by chemical agents with very different mechanisms of action. 

The criterion for a steady state is that the rate of reduction of the cathodic current density i m, is equal to the rate of oxidation of the reducing agent Red, the anodic current density... 

Whereas a wide range of potential allelopathic agents has been identified from soil micro-organisms, it has seldom been proven that they are of true ecological significance. The minimum necessary criterion for this is that the product should occur in the form and... 

The agent should provoke attacks that resemble the patient s clinical panic attacks. The panic attacks induced by CCK-4 have been appraised by patients to be identical or very similar to their spontaneous panic attacks in terms of the type and quality of symptoms (Bradwejn et al. 1991a). This has been an important criterion of panic attack in our studies with patients. Moreover, CCK-4 does not induce a stereotyped response in... 

Ballantyne and Swanston developed a laboratory procedure to measure the threshold concentrations of CS that produced sensation in the human eye and tongue, to compare various irritant agents. Threshold concentrations of CS were also measured in the rabbit and guinea pig with blepharospasm as the criterion of ocular response. 

---