Modulation of human aorta smooth muscle cell phenotype: a study of muscle-specific variants of vinculin, caldesmon, and actin expression.

Vinculin- and caldesmon-immunoreactive forms and actin isoform patterns were studied in samples of normal and atherosclerotic human aorta. After removal of adventitia and endothelium, the remaining tissue was divided into three layers: media, muscular-elastic (adjacent to media) intima, and subendothelial (juxtaluminal) intima. In media of normal aorta, meta-vinculin accounted for 41.0 +/- 0.9% (mean +/- SEM) of total immunoreactive vinculin (meta-vinculin + vinculin); 150-kDa caldesmon accounted for 78.2 +/- 5.1% of immunoreactive caldesmon (150-kDa + 70-kDa); the fractional contents of alpha-smooth muscle actin, beta-nonmuscle, and gamma-isoactins were 49.0 +/- 0.6%, 30.4 +/- 0.6%, and 20.8 +/- 0.8%, respectively. Muscular-elastic intima was very similar to media by these criteria. In subendothelial intima, the fractional content of meta-vinculin and 150-kDa caldesmon was significantly lower (6.9 +/- 1.5% and 32.7 +/- 7.0%, respectively) than in muscular-elastic intima and media, whereas the isoactin pattern was identical to that in adjacent layers, demonstrating the smooth muscle origin of subendothelial intima cells. In atherosclerotic fibrous plaque, the fractional content of alpha-actin was decreased in subendothelial intima, rather than in media and muscular-elastic intima. Additionally, the proportion of subendothelial intima cells [i.e., the cells that express low amounts of smooth muscle phenotype markers (meta-vinculin, 150-kDa caldesmon, and alpha-actin)] in the total intima cell population increased dramatically in atherosclerotic fibrous plaque. The results suggest that changes in the relative content of meta-vinculin and 150-kDa caldesmon as well as alpha-actin in human aortic intima are associated with atherosclerosis although, in subendothelial intima of normal aorta, a certain smooth muscle cell population exists that expresses reduced amounts of "contractile" phenotype markers, even in the absence of the disease.     

Molecular characterization of a high A2 beta thalassemia by direct sequencing of single strand enriched amplified genomic DNA

Two families, one of Anglo-Saxon-Dutch descent, and the other, West Indian black, have an atypical beta thalassemia characterized by an unusually high level of Hb A2 in the heterozygous state. Restriction endonuclease mapping showed a deletion of about 1.35 kilobase (kb) in the 5' region of the beta globin gene. Direct sequencing of a specific region of genomic DNA amplified by a new modification of the polymerase chain reaction defined the deletion to be 1,393 base pairs (bp) and to be the same in both families. The deletion extends from 485 bp 5' to the mRNA CAP site to the middle of the second intervening sequence. This deletion, together with three others previously described that remove the 5' end of the beta gene but leave the delta gene intact, are all associated with unusually high levels of Hb A2 in the heterozygous state.     

The Cretaceous superchron geodynamo: observations near the tangent cylinder

If relationships exist between the frequency of geomagnetic reversals and the morphology, secular variation, and intensity of Earth's magnetic field, they should be best expressed during superchrons, intervals tens of millions of years long lacking reversals. Here we report paleomagnetic and paleointensity data from lavas of the Cretaceous Normal Polarity Superchron that formed at high latitudes near the tangent cylinder that surrounds the solid inner core. The time-averaged field recorded by these lavas is remarkably strong and stable. When combined with global results available from lower latitudes, these data define a time-averaged field that is overwhelmingly dominated by the axial dipole (octupole components are insignificant). These observations suggest that the basic features of the geomagnetic field are intrinsically related. Superchrons may reflect times when the nature of core-mantle boundary heat flux allows the geodynamo to operate at peak efficiency.     

Instability of chromosome 6 microsatellite repeats in human cervical tumors carrying papillomavirus sequences

Loss of heterozygosity (LOH) in chromosome 6 in human squamous cervical carcinomas was analyzed in the long and short arms of the chromosome using 3 pairs of primers each. In all cases, normal adjacent tissue was used as control. Among 51 cases analyzed, we identified LOH or microsatellite instability in 23% using primer D6S291 (located at position 6p21.3) and in 11% using primers D6S308 (6q16.3–6q27) and D6S270 (6q22.3–6q23.2). On the contrary, no significant LOH or genomic instabilities were detected with primers D6S306 (6p22.3–6p21.2), D6S299 (6p22.3–6p21.3) and D6S287 (6q21–6q23.3). Our results thus suggest the existence of instable loci at 3 regions of chromosome 6. Whether these loci contain putative tumor-suppressor genes or genes involved in cell cycle control remains unknown. © 1996 Wiley-Liss, Inc.     

Evaluation of Mechanical and Electrical Performance of Aging Resistance ZTA Composites Reinforced with Graphene Oxide Consolidated by SPS

This paper presents a study of Al₂O₃–ZrO₂ (ZTA) nanocomposites with different contents of reduced graphene oxide (rGO). The influence of the rGO content on the physico-mechanical properties of the oxide composite was revealed. Graphene oxide was obtained using a modified Hummers method. Well-dispersed ZTA-GO nanopowders were produced using the colloidal processing method. Using spark plasma sintering technology (SPS), theoretically dense composites were obtained, which also reduced GO during SPS. The microstructure, phase composition, and physico-mechanical properties of the sintered composites were studied. The sintered ZTA composite with an in situ reduced graphene content of 0.28 wt.% after the characterization showed improved mechanical properties: bending strength was 876 ± 43 MPa, fracture toughness—6.8 ± 0.3 MPa·m^1/2 and hardness—17.6 ± 0.3 GPa. Microstructure studies showed a uniform zirconia distribution in the ZTA ceramics. The study of the electrical conductivity of reduced graphene oxide-containing composites showed electrical conductivity above the percolation threshold with a small content of graphene oxide (0.28 wt.%). This electrical conductivity makes it possible to produce sintered ceramics by electrical discharge machining (EDM), which significantly reduces the cost of manufacturing complex-shaped products. Besides improved mechanical properties and EDM machinability, 0.28 wt.% rGO composites demonstrated high resistance to hydrothermal degradation.     

Correction: The structural and luminescence properties of plexcitonic structures based on Ag2S/l-Cys quantum dots and Au nanorods

Correction for ‘The structural and luminescence properties of plexcitonic structures based on Ag₂S/l-Cys quantum dots and Au nanorods’ by Irina G. Grevtseva et al., RSC Adv., 2022, 12, 6525–6532, DOI: 10.1039/D1RA08806H.

The authors regret the omission of a funding acknowledgement in the original article. This acknowledgement is given below.This study was supported by the Ministry of Science and Higher Education of the Russian Federation under Agreement N 075-15-2021-1351 as part of the structural analysis of colloidal Ag₂S/l-Cys QDs and Au NRs.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Blood serum atherogenicity associated with coronary atherosclerosis. Evidence for nonlipid factor providing atherogenicity of low-density lipoproteins and an approach to its elimination

To reveal the presence of atherogenic potential in the blood serum obtained from patients with angiographically assessed coronary atherosclerosis we used primary cultures of subendothelial cells isolated by collagenase from unaffected human aortic intima. Earlier, we have demonstrated that such cultures are made up mostly of typical and modified smooth muscle cells. Within 24 hours of cultivation with a 40% sera of patients suffering from coronary atherosclerosis, the total intracellular cholesterol level increased twofold to fivefold. Cultivation with the sera of healthy subjects had no effect on the intracellular cholesterol level. The sera of patients were separated by ultracentrifugation into two fractions: total lipoprotein fraction containing the main classes of lipoproteins and a lipoprotein-deficient fraction. The former, but not the lipoprotein-deficient fraction, was characterized by atherogenicity (i.e., the ability to induce the accumulation of intracellular cholesterol). Lipoproteins of the patients' serum were separated into main classes: low density lipoproteins (LDL), very low density lipoproteins (VLDL), and high density lipoproteins (HDL2 and HDL3). An atherogenic component of the serum capable of stimulating the deposition of intracellular cholesterol was represented by LDL and, in one case, by VLDL, but not by other classes of lipoproteins. LDL and other lipoproteins isolated from the blood serum of healthy subjects failed to raise the cholesterol content in cultured cells; that is, they were nonatherogenic.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Ceruloplasmin on the Number and Resistance of Erythrocytes during Acute Physical Exercise

Acute physical exercise was followed by a decrease in the osmotic resistance of erythrocytes, shortening of the time-to-onset of erythrocyte hemolysis, and increase in the sorption capacity of the cell membrane. Administration of ceruloplasmin 24 h before physical exercise normalizes membrane resistance in red blood cells.