Biochemical and molecular analyses in three patients with 3-hydroxy-3-methylglutaric aciduria.

Two methods, spectrophotometry and HPLC, were compared in the analyses of 3-hydroxy-3-methylglutaryl-CoA lyase (HL) activity in three unrelated Czech patients with 3-hydroxy-3-methylglutaric (HMG) aciduria and their family members. The HL activities in cultured fibroblasts and/or isolated lymphocytes of probands were below the detection limits of the methods used. Both methods were also suitable for recognition of all heterozygotes in affected families. We searched for pathogenic mutations in the HL gene. Molecular analyses revealed that two patients are homozygous for known mutation H233R and R41Q, respectively, whereas the third patient is a compound heterozygote for the mutation H233R and a novel mutation Pro9fs(-1). This study expands the knowledge of the genotypic variability of the HMG aciduria.

First observation of meridional focusing of an X-ray beam using diffraction by a crystal with a transverse groove.

The possibility of concentrating a synchrotron X-ray beam using diffraction by a single crystal with a properly designed transverse groove on its surface, suggested earlier, has been studied experimentally. Here, the first experimental demonstration of this effect is reported, performed on beamline BM5 at the ESRF. The experimental result confirms the theoretical model.

Meridional focusing of X-rays diffracted onto a single crystal with a transversal groove (Bragg-diffraction asymmetric lens).

It is shown that a properly designed transversal groove machined into the surface of a single-crystal monochromator may concentrate (focus) the diffracted radiation meridionally. From this result and from previous papers on the Bragg-diffraction inclined lens it follows that a properly designed depression fabricated into the surface of a single-crystal monochromator should provide two-dimensional focusing of a diffracted synchrotron radiation beam.