On estimating penetrance of the retinoblastoma gene

Summary Centrometric fission of chromosome 10 is reported in a 25-year-old psychiatric patient and his 51/2-year-old normal daughter. The relevant literature on this subject is briefly reviewed.     

Preparation of multilayers containing chlorophylla and/or phosphatidylcholine and chemical stability of chlorophylla molecules in the multilayers

Summary The Langmuir-Blodgett films consisting of mixed monolayers containing chlorophylla (Chl-a) and/or phosphatidylcholine with various molar ratios could be well prepared on glass plates previously covered with three monolayers of cadmium eicosanate. Thin-layer and high-performance liquid chromatographic examinations revealed that the photostability of Chl-a molecules in various media is in the following order: the mixed mono- or multilayers >pure Chl-a mono- or multilayersorganic solvents.     

Metabolism of 1alpha-hydroxyvitamin D3 to 1alpha, 25-dihydroxyvitamin D3 in perfused rat liver.

The metabolism of 1α-hydroxyvitamin D₃ (1α-OH-D₃) was studied in rat liver perfused with [³H]-1α-OH-D₃. [³H]-1α-OH-D₃ was converted very rapidly to a more polar metabolite, which was identified as 1α,25-dihydroxy-vitamin D₃ [1α,25-(OH)₂-D₃] by co-chromatography with synthetic 1α,25-(OH)₂-D₃ as well as by gas chromatography-mass spectrometry. [³H]-1α,25-(OH)₂-D₃ appeared in the perfusate as early as 20 min after addition of [³H]-1α-OH-D₃, and its level in the perfusate increased linearly for at least 120 min. These data strongly indicate that 1α-OH-D₃ is metabolized to 1α,25-(OH)₂-D₃, which exerts biological effects on bone and intestine.     

Characterization of 2,7-anhydro-N-acetylneuraminic acid in human wet cerumen

A molecular species of sialic acid was isolated in a free form from cerumen of the wet type, but not of the dry type, by an ion-exchange column chromatography and preparative high-performance liquid chromatography. Structural analysis of this sialic acid was performed by gas-liquid chromatography/mass spectrometry with chemical ionization (CI) and electron ionization (EI). In the CI mass spectra, the protonated molecular ion of the trimethylsilyl derivative was observed at m/z 580. and that of the methyl ester-trimethylsilyl derivative was at m/z 522. In the EI mass spectrum, the methyl ester-trimethylsilyl derivative gave characteristic ions at m/z 506, 462, 418, 416, 328, 316, 238, 228, 205, 186, and 173. This mass spectrum was identical with that of 2,7-anhydro-N-acetylneuraminic acid, which was reported by Lifely and Cottee (Carbohydr. Res. 107, 187-197, 1982) as the mass spectrum of a by-product prepared from N-acetylneuraminic acid by methanolysis. These results indicate that the compound in the wet cerumen is 2,7-anhydro-N-acetylneuraminic acid. Since this sialic acid species could not be detected in cerumens of the dry type, its formation in the wet type may be controlled by an autosomal dominant gene.     

The Effect of Urea and Guanidine Hydrochloride on Activity of Papain

The inactivation of papain brought about by low concentration of urea or guanidine hydrochloride was found to be a non-competitive type and that of cyanate ion to be a mixed type. The results are presented as Lineweaver-Burk plots.

These inactivations are not due to a change in the secondary structure of papain molecule as a result of the measurements of optical rotatory dispersion, circular dichroism, and UV-difference spectra.     

Prodigiosin-25 C

A water-insoluble red antibiotic pigment was isolated from mycelia of a strain of Streptomyces. It was found that the pigment is a new C₂₅-prodigiosin-analogue and the authors propose to designate it prodigiosin-25 C. The chemical structure (XI) has been deduced from visible absorption spectra, NMR spectra, mass spectra and analysis of degradation products of the pigment.     

A new approach in the evaluation of chromosome variants in man

Summary Chromosome variants were evaluated on the basis of their DNA-replication pattern (LBA). The size of late-replicating centromeric heterochromatin of chromosomes 2, 5, 6, 7, 8, 10, 11, 12, 17, 18, 19, and 20, i.e., pairs without Q or C (qh) variants, was measured by means of a microdensitometer. The results were expressed in area, related to that of a euchromatic segment of a given chromosome, and were assigned into five classes based on the difference in standard deviation from an average relative size. LBA variants in each of 12 pairs were found in 29%–42% of the chromosomes.     

n-Dodecyl β-D-maltoside specifically competes with general anesthetics for anesthetic binding sites

We recently demonstrated that the anionic detergent sodium dodecyl sulfate (SDS) specifically interacts with the anesthetic binding site in horse spleen apoferritin, a soluble protein which models anesthetic binding sites in receptors. This raises the possibility of other detergents similarly interacting with and occluding such sites from anesthetics, thereby preventing the proper identification of novel anesthetic binding sites. n-Dodecyl β-D-maltoside (DDM) is a non-ionic detergent commonly used during protein-anesthetic studies because of its mild and non-denaturing properties. In this study, we demonstrate that SDS and DDM occupy anesthetic binding sites in the model proteins human serum albumin (HSA) and horse spleen apoferritin and thereby inhibit the binding of the general anesthetics propofol and isoflurane. DDM specifically interacts with HSA (K_d?=?40?μM) with a lower affinity than SDS (K_d?=?2?μM). DDM exerts all these effects while not perturbing the native structures of either model protein. Computational calculations corroborated the experimental results by demonstrating that the binding sites for DDM and both anesthetics on the model proteins overlapped. Collectively, our results indicate that DDM and SDS specifically interact with anesthetic binding sites and may thus prevent the identification of novel anesthetic sites. Special precaution should be taken when undertaking and interpreting results from protein-anesthetic investigations utilizing detergents like SDS and DDM.     

Effects of rosuvastatin on electronegative LDL as characterized by capillary isotachophoresis: the ROSARY Study

Electronegative LDL, a charge-modified LDL (cm-LDL) subfraction that is more negatively charged than normal LDL, has been shown to be inflammatory. We previously showed that pravastatin and simvastatin reduced the electronegative LDL subfraction, fast-migrating LDL (fLDL), as analyzed by capillary isotachophoresis (cITP). The present study examined the effects of rosuvastatin on the more electronegative LDL subfraction, very-fast-migrating LDL (vfLDL), and small, dense charge-modified LDL (sd-cm-LDL) subfractions. Patients with hypercholesterolemia or those who were being treated with statins (n = 81) were treated with or switched to 2.5 mg/d rosuvastatin for 3 months. Rosuvastatin treatment effectively reduced cITP cm-LDL subfractions of LDL (vfLDL and fLDL) or sdLDL (sd-vfLDL and sd-fLDL), which were closely related to each other but were different from the normal subfraction of LDL [slow-migrating LDL (sLDL)] or sdLDL (sd-sLDL) in their relation to the levels of remnant-like particle cholesterol (RLP-C), apolipoprotein (apo) C-II, and apoE. The percent changes in cm-LDL or sd-cm-LDL caused by rosuvastatin were correlated with those in the particle concentrations of LDL or sdLDL measured as LDL-apoB or sdLDL-apoB and the levels of HDL-C, RLP-C, apoC-II, and apoE. In conclusion, rosuvastatin effectively reduced both the vfLDL subfraction and sd-cm-LDL subfractions as analyzed by cITP.