Trial Terms

The site contains information on thousands of clinical studies sponsored by the NIH, other federal agencies, and the pharmaceutical industry in about 100,000 locations worldwide. Studies listed in the database are conducted primarily in the United States and Canada, but include locations in about 90 countries. ClinicalTrials.gov gives information about a trial s purpose, who may participate, locations, and phone numbers for more details. In addition, a glossary is available that will help people become familiar with the most common clinical trial terms. 

Phase II trials, termed dose finding studies, in a table listing the length of the study period and the number of subjects. Results of the Crixivan trials were compared to other treatments, especially AZT when taken alone. Phase III trials, generally considered key to determining efficacy, are described as confirmatory trials, since Crixivan s early success had put it on an accelerated track. 

Hannah ME, Hannah WJ, Hewson SA, et al. (2000) Planned caesarean section versus planned vaginal birth for breech presentation at term a randomised multicentre trial. Term Breech Trial Collaborative Group. Lancet 356 1375-1483... 

The preclinical trials are performed in in vitro and animal studies to assess the biological activity of the new compound. In phase 1 of the clinical trials the safety of a new drug is examined and the dosage is determined by administering the compound to about 20 to 100 healthy volunteers. The focus in phase II is directed onto the issues of safety, evaluation of efficacy, and investigation of side effects in 100 to 300 patient volimteers. More than 1000 patient volunteers are treated with the new drug in phase 111 to prove its efficacy and safety over long-term use. 

As formulated above in terms of spin-orbitals, the Hartree-Fock (HF) equations yield orbitals that do not guarantee that P possesses proper spin symmetry. To illustrate the point, consider the form of the equations for an open-shell system such as the Lithium atom Li. If Isa, IsP, and 2sa spin-orbitals are chosen to appear in the trial function P, then the Fock operator will contain the following terms ... 

Certain neutral technetium complexes can be used to image cerebral perfusion (Fig. 4). Those in Figure 4a and 4b have been approved for clinical use. Two other complexes (Fig. 4c and 4d) were tested in early clinical trials, but were not developed further. An effective cerebral perfusion agent must first cross the blood brain barrier and then be retained for the period necessary for image acquisition. Tc-bicisate is retained owing to a stereospecific hydrolysis in brain tissue of one of the ester groups to form the anionic complex TcO(ECD) , which does not cross the barrier. This mechanism of retention is termed metaboHc trapping. 

There have been a number of long-term trials with various P-adrenoceptor blockers in patients surviving acute MI (37—39) that demonstrated a reduction in mortaUty, sudden death, and nonfatal re-infarctions. The term cardioprotective has been used to describe this effect for the dmgs studied. The... 

The use of selective P-antagonists for treatment of CHF has included the P -blocker metoprolol (Table 1) and results of clinical trials suggest long-term beneficial effects. Selective P -antagonists have also been tested, an example of which is xamoterol [81801 -12-9], C2 H25N20, which is (i)-A/-(2-hydroxy-3-(4-hydroxyphenoxy)propylamino)ethylmorphine-4-carboxamide. Xamoterol exhibits approximately 50% of the activity of isoproterenol, and serves to provide modest inotropic effects (128,129). 

Cromakalim. Cromakalim has along half-life (254). Cromakalim at an oral dose of 1.5 mg ia humans significantly lowers blood pressure 19/12 mm Hg (systohc/diastoHc pressure). It iacreases reaal blood flow, PRA, and heart rate. Cromakalim has bronchodilating activity that is beneficial for hypertensive asthmatic patients. Because of some undesirable effects seen ia cardiac papillary muscles of animals oa long-term treatmeat, future clinical trials are to be carried out usiag the active enantiomer, lemakalim (BRL 38227). 

There is a great difference between various simulators (5) in terms of how easily and how well the hypothetical calculation units can be incorporated in the simulation. The trial-and-error calculations, which ate called iterative calculations, do not always converge for every flow sheet being simulated. Test problems can be devised to be tried with various simulators to see if the simulator will give a converged solution (11). Different simulators could take different numbers of iterations to converge and take different amounts of computet time on the same computet. 

Compared to streptokinase, urokinase has been less extensively studied because of its high cost, ie, about 10 times that of a comparable treatment with streptokinase. In addition to the indications described for streptokinase, urokinase is indicated for use in patients with prior streptokinase treatment, or prior Streptococcal infection. Urokinase is commonly used at a loading dose of 4400 units /kg, with a maintenance intravenous infusion dose of 4400 units/kg/h for thromboses other than acute myocardial infarction. In the latter case, a much larger dose, ie, 0.5—2.0 million units/h or a bolus dose of 1.0 million units followed by a 60-min infusion with 1.0 million units, has been found optimal (106). An intracoronary dose of 2000 units/min for two hours was used in one comparative study with intracoronary streptokinase (107). In this study, urokinase exhibited efficacy equivalent to streptokinase with fewer side effects. Other studies with intracoronary urokinase have adrninistered doses ranging from 2,000 to 24,000 units/min with a reperfusion efficacy of 60—89% (108—112). In another urokinase trial, 2.0 million units were adrninistered intravenously, resulting in a thrombolytic efficacy of 60% (113). Effectiveness in terms of reduction in mortaUty rate has not been deterrnined because of the small number of patients studied. 

Though this is a quartic equation, it is capable of explicit solution because of the absence of second and third degree terms. Trial-and-error enters, however, because (GSi)r and are mild functions of Tg and related Te, respectively, and aprehminary guess of Tg is necessaiy. An ambiguity can exist in interpretation of terms. If part of the enclosure surface consists of screen tubes over the chamber-gas exit to a convection section, radiative transfer to those tubes is included in the chamber energy balance, but convection is not, because it has no effect on chamber gas temperature. 

Alth ough the equihbrium constant can be evaluated in terms of kinetic data, it is usually found independently so as to simplify finding the other constants of the rate equation. With known, the correct exponents of Eq. (7-64) can be found by choosing trial sets until /ci comes out approximately constant. When the exponents are small integers or simple fractious, this process is not overly laborious. 

Provided that no learning process is involved (so that the value of Pi is not influenced by previous results), the probabihty of x successes in n trials is given by the term containing pf in the expansion of the binomial ... 

The above expression ean be solved by a trial and error ealeulation, whereby the following key assumptions are applied (1) the flow is turbulent, i.e., Re s 2,100, and (2) motive power is supplied by a prime mover sueh as a pump or a eompressor. To make this expression easier to use, the terms are rearranged in the following maimer ... 

The value of n must be found by trial-and-error. In terms of the fraetional eonversion, X, the rate equation is... 

So far there have not been any restrictions on the MOs used to build the determinantal trial wave function. The Slater determinant has been written in terms of spinorbitals, eq. (3.20), being products of a spatial orbital times a spin function (a or /3). If there are no restrictions on the form of the spatial orbitals, the trial function is an Unrestricted Hartree-Fock (UHF) wave function. The term Different Orbitals for Different Spins (DODS) is also sometimes used. If the interest is in systems with an even number of electrons and a singlet type of wave function (a closed shell system), the restriction that each spatial orbital should have two electrons, one with a and one with /3 spin, is normally made. Such wave functions are known as Restricted Hartree-Fock (RHF). Open-shell systems may also be described by restricted type wave functions, where the spatial part of the doubly occupied orbitals is forced to be the same this is known as Restricted Open-shell Hartree-Fock (ROHF). For open-shell species a UHF treatment leads to well-defined orbital energies, which may be interpreted as ionization potentials. Section 3.4. For an ROHF wave function it is not possible to chose a unitary transformation which makes the matrix of Lagrange multipliers in eq. (3.40) diagonal, and orbital energies from an ROHF wave function are consequently not uniquely defined, and cannot be equated to ionization potentials by a Koopman type argument. 

The direct-solution method of Akers and Wade [1] is among several which attempt to reduce the amount of trial-and-error solutions. This has been accomplished and has proven quite versatile in application. The adaptation outlined modifies the symbols and rearranges some terms for convenient use by the designer [3]. Dew point and bubble point compositions and the plate temperatures can be determined directly. Constant molal overflow is assumed, and relative volatility is held constant over sections of the column. 

To facilitate trial-and-error work, the following constant terms are calculated ... 

Continue for number of terms on right side of equation equal to number of stages. This is usually best solved by trial and error and can be simplified if most of the AP values are assumed equal. It assumes all the intercooler pressure drop is deducted from the suction pressure of the succeeding stage, i.e., first stage intercooler pressure drop is deducted from second stage suction pressure. 

The second term on the right side of the expression for AH accounts for any phase changes that may occur between 25°C and for the final products it should be deleted if not applicable. Using molal heat capacity data C (T) for all the species present, the following equality is solved for by trial and error. 

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