Lower diastolic wall strain is associated with coronary revascularization in patients with stable angina

Background

Left ventricular (LV) diastolic dysfunction occurs earlier in the ischemic cascade than LV systolic dysfunction and electrocardiographic changes. Diastolic wall strain (DWS) has been proposed as a marker of LV diastolic stiffness. Therefore, the objectives of this study were to define the relationship between DWS and coronary revascularization and to evaluate other echocardiographic parameters in patients with stable angina who were undergoing coronary angiography (CAG).

Methods

Four hundred forty patients [mean age: 61?±?10; 249 (57%) men] undergoing CAG and with normal left ventricular systolic function without regional wall motion abnormalities were enrolled. Among them, 128 (29%) patients underwent revascularization (percutaneous intervention: 117, bypass surgery: 11). All patients underwent echocardiography before CAG and the DWS was defined using posterior wall thickness (PWT) measurements from standard echocardiographic images [DWS?=?PWT(systole)-PWT(diastole)/PWT(systole)].

Results

Patients who underwent revascularization had a significantly lower DWS than those who did not (0.26?±?0.08 vs. 0.38?±?0.09, p?<?0.001). Age was comparable between the two groups (61?±?9 vs. 60?±?11, p?=?0.337), but the proportion of males was significantly higher among patients who underwent revascularization (69 vs. 52%, p?=?0.001). The LV ejection fraction was similar but slightly decreased (60.9?±?5.7 vs. 62.4?±?6.2%, p?=?0.019) and the E/E’ ratio was elevated (10.3?±?4.0 vs. 9.0?±?3.1, p?<?0.001) among patients who underwent revascularization. In multiple regression analysis, lower DWS was an independent predictor of revascularization (cut-off value: 0.34; sensitivity: 89%; AUC: 0.870; SE: 0.025; p?<?0.001).

Conclusion

DWS, a simple parameter that can be calculated from routine 2D echocardiography, is inversely associated with the presence of coronary artery disease and the need for revascularization.

     

Mild pretreatment of yellow poplar biomass using sequential dilute acid and enzymatically-generated peracetic acid to enhance cellulase accessibility

Biomass contains cellulose, xylan and lignin in a complex interwoven structure that hinders enzymatic hydrolysis of the cellulose. To separate these components in yellow poplar biomass, we sequentially pretreated with dilute sulfuric acid and enzymatically-generated peracetic acid. In the first step, the dilute acid with microwave heating (140°C, 5 min) hydrolyzed 90% of xylan. The xylose yield in hydrolysate after dilute acid pretreatment was 83.1%. In the second step, peracetic acid (60°C, 6 h) removed up to 80% of lignin. This sequential pretreatment fractionated biomass into xylan and lignin, leaving a solid residue enriched in cellulose (~80%). The sequential pretreatment enhanced enzymatic digestibility of the cellulase by removal of the other components in biomass. The glucose yield after enzymatic hydrolysis was 90.5% at a low cellulase loading (5 FPU/g of glucan), which is 1.6 and 18 times higher than for dilute acid-pretreated biomass and raw biomass, respectively. This novel sequential pretreatment with dilute acid and peracetic acid efficiently separates the three major components of yellow poplar biomass, and reduces the amount of cellulase needed.     

Cloning and characterization of two genes encoding sulfate transporters from rice (Oryza sativa L.)*

Two genes were isolated from a rice genomic library and the coding region of their corresponding cDNAs generated by RT-PCR. These single copy genes, designated ORYsa;Sultr1;1 and ORYsa;Sultr4;1, encode putative sulfate transporters. Both genes encode proteins with predicted topologies and signature sequences of the H⁺/SO₄^2- symporter family of transporters and exhibit a high degree of homology to other plant sulfate transporters. ORYsa;Sultr1;1 is expressed in roots with levels of expression being strongly enhanced by sulfate starvation. In situ hybridization experiments revealed that ORYsa;Sultr1;1 expression is localized to the main absorptive region of roots. This gene probably encodes a transporter that is responsible for uptake of sulfate from the soil solution. In contrast, ORYsa;Sultr4;1 was expressed in both roots and shoots and was unresponsive to the sulfur status of the plant. The sequence of ORYsa;Sultr4;1 contains a possible plastid-targeting transit peptide which may indicate a role in transport of sulfate to sites of sulfate reduction in plastids. The role of the transporter encoded by ORYsa;Sultr4;1 is likely to be significantly different fromORYsa;Sultr1;1. These are the first reports of isolation of genes encoding sulfate transporters from rice and provide a basis for further studies involving sulfate transport.     

Interactions of neural glycosaminoglycans and proteoglycans with protein ligands: assessment of selectivity, heterogeneity and the participation of core proteins in binding

The method of affinity coelectrophoresis was used to study the binding of nine representative glycosaminoglycan (GAG)-binding proteins, all thought to play roles in nervous system development, to GAGs and proteoglycans isolated from developing rat brain. Binding to heparin and non-neural heparan and chondroitin sulfates was also measured. All nine proteins-laminin-1, fibronectin, thrombospondin-1, NCAM, L1, protease nexin-1, urokinase plasminogen activator, thrombin, and fibroblast growth factor-2-bound brain heparan sulfate less strongly than heparin, but the degree of difference in affinity varied considerably. Protease nexin-1 bound brain heparan sulfate only 1.8- fold less tightly than heparin (Kdvalues of 35 vs. 20 nM, respectively), whereas NCAM and L1 bound heparin well (Kd approximately 140 nM) but failed to bind detectably to brain heparan sulfate (Kd>3 microM). Four proteins bound brain chondroitin sulfate, with affinities equal to or a few fold stronger than the same proteins displayed toward cartilage chondroitin sulfate. Overall, the highest affinities were observed with intact heparan sulfate proteoglycans: laminin-1's affinities for the proteoglycans cerebroglycan (glypican-2), glypican-1 and syndecan-3 were 300- to 1800-fold stronger than its affinity for brain heparan sulfate. In contrast, the affinities of fibroblast growth factor-2 for cerebroglycan and for brain heparan sulfate were similar. Interestingly, partial proteolysis of cerebroglycan resulted in a >400- fold loss of laminin affinity. These data support the views that (1) GAG-binding proteins can be differentially sensitive to variations in GAG structure, and (2) core proteins can have dramatic, ligand-specific influences on protein-proteoglycan interactions.      

Contrasting population structure from nuclear intron sequences and mtDNA of humpback whales

Powerful analyses of population structure require information from multiple genetic loci. To help develop a molecular toolbox for obtaining this information, we have designed universal oligonucleotide primers that span conserved intron-exon junctions in a wide variety of animal phyla. We test the utility of exon-primed, intron-crossing amplifications by analyzing the variability of actin intron sequences from humpback, blue, and bowhead whales and comparing the results with mitochondrial DNA (mtDNA) haplotype data. Humpback actin introns fall into two major clades that exist in different frequencies in different oceanic populations. It is surprising that Hawaii and California populations, which are very distinct in mtDNAs, are similar in actin intron alleles. This discrepancy between mtDNA and nuclear DNA results may be due either to differences in genetic drift in mitochondrial and nuclear genes or to preferential movement of males, which do not transmit mtDNA to offspring, between separate breeding grounds. Opposing mtDNA and nuclear DNA results can help clarify otherwise hidden patterns of structure in natural populations.      

Variable effect of playback of chickadee mobbing calls on detection probability of boreal forest birds

Modification of the point count survey method to include playback of songbird mobbing calls in an attempt to increase detection probabilities has met with mixed success. We compared detection probabilities for boreal forest songbirds using traditional point count methods and counts using broadcasts of the mobbing calls of Black‐capped Chickadees (Poecile atricapillus) in an attempt to increase detection probability. We conducted 594 point counts during the 2010 breeding season in Newfoundland, Canada. Each point count consisted of an 8‐min silent observation period followed by an 8‐min broadcast of Black‐capped Chickadee mobbing calls. Occupancy model results showed that response to playback broadcast varied across species, with detection probabilities higher for seven of 17 species during the silent portions of point counts and three species more likely to be detected during playback intervals. For all species, the number of visual detections increased during periods of playback and, averaged across species, individuals were >6 times more likely to be seen during the playback period than during the silent period. Differences in detection probability among observers were apparent during both silent and playback periods. We suggest that using playback of chickadee mobbing calls during point count surveys of common boreal forest songbird species may be most beneficial when visual detection is important. However, playback may also be useful for species‐specific surveys during periods when birds are less likely to be vocal or for studies of less common species with chronically low detection probabilities. A combined silent and playback approach could also be useful, although observer and species differences should be accounted for if comparing data across species or studies.     

Isolation of cloned Syrian hamster insulinoma cell lines with limited capacity for insulin production.

Cell lines derived from a Syrian hamster insulinoma have been cloned in agar and maintained continuously in culture in vitro for 1 1/2 years. The cell lines have average doubling times of 48 h, they have modal chromosome numbers between 38 and 39, and they retain the ability to form tumors when injected into Syrian hamsters. The cells do not produce immunoreactive insulin when grown in vitro (less than 0.5 ng/mg protein), but do produce immunoreactive insulin when grown in vivo as tumors (mean value from six determinations = 7.1 +/- 1.5 ng/mg protein).     

Survival of Campylobacter jejuni in raw, pasteurized and ultra-heat-treated goat's milk stored at different temperatures

The survival of a human strain of Campylobacter jejuni in raw, pasteurized and ultra-heat-treated goat's milk stored at 5°, 10°, 15° and 20°C was studied. No viable units were detected in raw milk after 24 h at 20°C and 48 h at 15°C. None were detected in pasteurized milk after 48 h at 20°C. In all other samples, there was a decline in viable units in the first 24 h but very little decline in the next 24 h period. The organism survived best at 5° and 10° C.