Acceptability and profile of the clinical drug trials underway in Finnish university hospitals in the 1990s: applications reviewed by ethics committees.

There is scarce information in literature about the decisions made by ethics committees concerning the clinical studies they have reviewed. A retrospective, detailed review of 666 applications, their amendments and the ethics committees' statements was undertaken. All protrocols of clinical studies on medicinal products submitted to and reviewed by the ethics committees of two university hospitals during the years 1992, 1994, 1996 and 1998 were investigated. Most of the studies were international (50%), multicenter (71%), phase III trials (41%) on a new clinical entity, (38%). Validity of the clinical drug study applications was acceptable in more than half of the cases (364; 55%), while 91 (14%) were approved with advisory comments, 153 (23%) had to be amended, 35 (5%) were left pending and 23 (3%) were rejected. Most of the questions pertained to informed consent and the study protcol. In accordance with precious results, our findings support the opinion that the submitted documents need to be improved, especially with regard to informed consent and study protocols, in order to gain better Good Clinical Practice (GCP) compliance. Well-defined, documented operating procedures of the ethics committees would have facilitated the practical issues in the review process.

Dark self-enhancement in dichromated poly(vinyl alcohol) gratings: a detailed study.

Experimental results concerning the real-time hologram recording process in dichromated poly(vinyl alcohol) are presented. Self-enhancement, the increase in diffraction efficiency of the holographic gratings in the dark after recording, is also presented. The influence of the recording parameters (pH, exposure energy, dichromate concentration) on the self-enhancement gain is shown. Maximum gain was 6, and self-enhancement occurred during the 3 days following the exposure. The results and a model for the reduction of chromium ions corresponding to the formation of the grating are discussed.

Dark self-enhancement in dichromated-gelatin gratings: a detailed study.

Strong dark self-enhancement, the increase in diffraction efficiency after irradiation, has been reported previously for dichromated-gelatin gratings. Here a more-detailed study of this self-enhancement effect is presented. The self-enhancement in dichromated-gelatin gratings was of the order of 10-100, depending on the pH and on the dichromate concentration of the solution used for the preparation of dichromated-gelatin films. The highest self-enhancement gain occurred when pH was high and dichromate concentration was low. The increase in the diffraction efficiencies of the gratings continued over 3 months.

Self-enhancement of holographic gratings in dichromated gelatin and polyvinyl alcohol films.

New experimental results concerning real-time hologram recording in dichromated sensitized gelatin and polyvinyl alcohol are presented. Self-enhancement of the holographic gratings observed in the dark in both of these dye-polymer systems is shown.

Fluorescence and phase-conjugated signals of organic materials.

The role of fluorescence has not always been fully understood in optical engineering experiments that are devoted to the generation of phase-conjugated waves from organic materials. It is pointed out that fluorescence can appear if the material absorbs at the wavelength of the excitation. Therefore proper experimental precautions should be taken in the detection of the intrinsic phase-conjugated signal.

Specific and sensitive quantitation of medroxyprogesterone acetate in human serum by gas chromatography-mass spectrometry.

A procedure for the quantitation of medroxyprogesterone acetate in serum using gas chromatography-quadrupole mass spectrometry is described. Medroxyprogesterone propionate, synthesized from medroxyprogesterone, was used as the internal standard. The serum samples were extracted on Bond Elut C18 cartridges, and the acetate and propionate were determined as their 3-enol heptafluorobutyrate esters by selected-ion monitoring technique. The linear range of the standard curve in serum was 0.5-30 ng/ml with a lower limit of quantitation of 0.5 ng/ml. The coefficient of variation of the method was 3.1% at 10 ng/ml and 5.5% at 1 ng/ml. The method is very rapid, and it has been applied for routine measurements of medroxyprogesterone acetate levels in human serum after oral administration of 10 or 20 mg.

Influence of some development parameters on the reflection grating structure in dichromated gelatin.

We made reflection gratings by using the gelatin of Kodak 649F spectroscopic plates. The concentration of ammonium dichromate sensitizer was varied, and reflection efficiencies of fully developed plates were measured in different reconstructing angles. During the development process we varied the washing time, the time interval between the washing and isopropanol baths, and the duration of the isopropanol bath. The reflection efficiencies were measured for each processing variable. Finally, the characteristics of the gratings were tested by varying the recording geometry.