Myocardial function and structure in aortic valve disease before and after surgery

Left ventricular (LV) micromanometry, cine-angiography and endomyocardial biopsies were performed in 13 patients with aortic valve disease {AVD) before and 12 to 28 months after successful valve replacement. (AVR). Patients with coronary artery disease were excluded. In nine patients (Group I: five AS, four AI) postoperative LV ejection fraction (EF) and total pressure Vmax were normal(EF ≥ 0.61; Vmax ≥ 1.50 ML/s). In four patients (Group II: three AS, one AT) postoperative EF (0.41) and Vmax (1.21 ML/s) were depressed. Pre-operative muscle fiber diameter (MFD; normal < 20 n) was 31 μ in Group I and 38 μ in Group II (P < 0.01). After AVR MFD decreased to 27 μ in Group I (P < 0.005) and to 28 μ in Group II (P < 0.02). Prior to surgery EF and Vmax showed no significant correlation with the LV fibrous content (FC in g/m2; FC = interstitial fibrosis in percent × LV angiographic muscle mass/100) in the 13 patients with AVD. After AVR, however, FC was related inversely to EF (P < 0.01, r = −0.69) and to Vmax (P < 0.025, r = −0.63). It is concluded that: (1) in AVD massive pre-operative fiber hypertrophy heralds impaired postoperative LV function; (2) fiber hypertrophy regresses following AVR regardless of the-LV functional state, and (3) the content of fibrous tissue appears to be a determinant of postoperative LV functio

Comparative transcriptome analysis coupled to X-ray CT reveals sucrose supply and growth velocity as major determinants of potato tuber starch biosynthesis

<p>Abstract</p> <p>Background</p> <p>Even though the process of potato tuber starch biosynthesis is well understood, mechanisms regulating biosynthesis are still unclear. Transcriptome analysis provides valuable information as to how genes are regulated. Therefore, this work aimed at investigating transcriptional regulation of starch biosynthetic genes in leaves and tubers of potato plants under various conditions. More specifically we looked at gene expression diurnally in leaves and tubers, during tuber induction and in tubers growing at different velocities. To determine velocity of potato tuber growth a new method based on X-ray Computed Tomography (X-ray CT) was established.</p> <p>Results</p> <p>Comparative transcriptome analysis between leaves and tubers revealed striking similarities with the same genes being differentially expressed in both tissues. In tubers, oscillation of granule bound starch synthase (GBSS) expression) was observed which could be linked to sucrose supply from source leaves. X-ray CT was used to determine time-dependent changes in tuber volume and the growth velocity was calculated. Although there is not a linear correlation between growth velocity and expression of starch biosynthetic genes, there are significant differences between growing and non-growing tubers. Co-expression analysis was used to identify transcription factors positively correlating with starch biosynthetic genes possibly regulating starch biosynthesis.</p> <p>Conclusion</p> <p>Most starch biosynthetic enzymes are encoded by gene families. Co-expression analysis revealed that the same members of these gene families are co-regulated in leaves and tubers. This suggests that regulation of transitory and storage starch biosynthesis in leaves and tubers, respectively, is surprisingly similar. X-ray CT can be used to monitor growth and development of belowground organs and allows to link tuber growth to changes in gene expression. Comparative transcriptome analysis provides a useful tool to identify transcription factors possibly involved in the regulation of starch biosynthesis.</p

Biological measurement beyond the quantum limit

Quantum noise places a fundamental limit on the per photon sensitivity attainable in optical measurements. This limit is of particular importance in biological measurements, where the optical power must be constrained to avoid damage to the specimen. By using non-classically correlated light, we demonstrated that the quantum limit can be surpassed in biological measurements. Quantum enhanced microrheology was performed within yeast cells by tracking naturally occurring lipid granules with sensitivity 2.4 dB beyond the quantum noise limit. The viscoelastic properties of the cytoplasm could thereby be determined with a 64% improved measurement rate. This demonstration paves the way to apply quantum resources broadly in a biological context

Somatic mosaicism and common genetic variation contribute to the risk of very-early-onset inflammatory bowel disease

Abstract: Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10−10), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10−10). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis