Enhanced production of 3,4-dihydroxybutyrate from xylose by engineered yeast via xylonate re-assimilation under alkaline condition.

To realize lignocellulose-based bioeconomy, efficient conversion of xylose into valuable chemicals by microbes is necessary. Xylose oxidative pathways that oxidize xylose into xylonate can be more advantageous than conventional xylose assimilation pathways because of fewer reaction steps without loss of carbon and ATP. Moreover, commodity chemicals like 3,4-dihydroxybutyrate and 3-hydroxybutyrolactone can be produced from the intermediates of xylose oxidative pathway. However, successful implementations of xylose oxidative pathway in yeast have been hindered because of the secretion and accumulation of xylonate which is a key intermediate of the pathway, leading to low yield of target product. Here, high-yield production of 3,4-dihydroxybutyrate from xylose by engineered yeast was achieved through genetic and environmental perturbations. Specifically, 3,4-dihydroxybutyrate biosynthetic pathway was established in yeast through deletion of ADH6 and overexpression of yneI. Also, inspired by the mismatch of pH between host strain and key enzyme of XylD, alkaline fermentations (pH ≥ 7.0) were performed to minimize xylonate accumulation. Under the alkaline conditions, xylonate was re-assimilated by engineered yeast and combined product yields of 3,4-dihydroxybutyrate and 3-hydroxybutyrolactone resulted in 0.791 mol/mol-xylose, which is highest compared with previous study. These results shed light on the utility of the xylose oxidative pathway in yeast.

Ability of S100 proteins and matrix metalloproteinase-9 to identify periodontitis in a ligature-induced periodontitis dog model.

AIMS: The present study aimed to monitor the levels of selected salivary biomarkers during the development and treatment of periodontitis and to evaluate their ability to identify periodontitis in dogs. MATERIALS AND METHODS: A total of 15 beagle dogs were divided into a control group (no ligature), group 1 (ligature on six teeth), and group 2 (ligature on 12 teeth). The experimental periods consisted of 8 weeks of periodontitis induction and 4 weeks of treatment. Clinical measurements and the sampling of saliva were performed every 4 weeks. The levels of S100A8, S100A9, S100A8/A9, and matrix metalloproteinase (MMP)-9 were measured by enzyme-linked immunosorbent assay. RESULTS: All experimental animals and two control animals developed periodontitis, which was successfully treated. All salivary biomarkers were significantly increased in periodontitis with high diagnostic power (c-index ≥ 0.944) and were able to identify animals with periodontitis on a single tooth. Whereas the levels of salivary S100A8/A9 recovered to levels in health, those of S100A8, S100A9, and MMP-9 in periodontitis stability remained significantly higher than in health. CONCLUSION: Salivary S100A8, S100A9, S100A8/A9, and MMP-9 may be used for the screening of periodontitis in dogs, but with caution of other conditions that can affect their levels in saliva.

The heat-shock protein-70-induced renoprotective effect is partially mediated by CD4+ CD25+ Foxp3 + regulatory T cells in ischemia/reperfusion-induced acute kidney injury.

Recent reports suggest the presence of heat-shock protein (HSP)-reactive T cells with a regulatory phenotype in various inflammatory diseases. To test whether HSP exerts renoprotective effects through regulatory T cells (Tregs), ischemia/reperfusion injury was done with or without heat preconditioning in mice. Splenocytes from heat-preconditioned mice had Treg expansion and a reduced proliferative response upon mitogenic stimulus. T cells from heat-preconditioned mice failed to reconstitute postischemic injury when adoptively transferred to T cell-deficient nu/nu mice in contrast to those from control mice. Tregs were also increased in heat-preconditioned ischemic kidneys. Depleting Tregs before heat preconditioning abolished the renoprotective effect, while adoptive transfer of these cells back into Treg-depleted mice partially restored the beneficial effect of heat preconditioning. Inhibition of HSP70 by quercetin suppressed Treg expansion, as well as renoprotective effects. Transferring Tregs in quercetin-treated heat-preconditioned mice partially restored the beneficial effect of heat preconditioning. The specificity of immune cell HSP70 in renoprotection was confirmed by partial restoration of kidney injury when T cells from HSP70-deficient heat preconditioned mice were adoptively transferred to nu/nu mice. Thus, the renoprotective effect of HSP70 may be partially mediated by a direct immunomodulatory effect through Tregs. Better understanding of immunomodulatory mechanisms of various stress proteins might facilitate discovery of new preventive strategies in acute kidney injury.

Long-term outcomes of mechanical valve replacement in patients with atrial fibrillation: impact of the maze procedure.

BACKGROUND: The long-term benefits of the maze procedure in patients with chronic atrial fibrillation undergoing mechanical valve replacement who already require lifelong anticoagulation remain unclear. METHODS AND RESULTS: We evaluated adverse outcomes (death; thromboembolic events; composite of death, heart failure, or valve-related complications) in 569 patients with atrial fibrillation-associated valvular heart disease who underwent mechanical valve replacement with (n=317) or without (n=252) a concomitant maze procedure between 1999 and 2010. After adjustment for differences in baseline risk profiles, patients who had undergone the maze procedure were at similar risks of death (hazard ratio, 1.15; 95% confidence interval, 0.65-2.03; P=0.63) and the composite outcomes (hazard ratio, 0.82; 95% confidence interval, 0.50-1.34; P=0.42) but a significantly lower risk of thromboembolic events (hazard ratio, 0.29; 95% confidence interval, 0.12-0.73; P=0.008) compared with those who underwent valve replacement alone at a median follow-up of 63.6 months (range, 0.2-149.9 months). The effect of superior event-free survival by the concomitant maze procedure was notable in a low-risk EuroSCORE (0-3) subgroup (P=0.049), but it was insignificant in a high-risk EuroSCORE (≥4) subgroup (P=0.65). Furthermore, the combination of the maze procedure resulted in superior left ventricular (P<0.001) and tricuspid valvular functions (P<0.001) compared with valve replacement alone on echocardiographic assessments performed at a median of 52.7 months (range, 6.0-146.8 months) after surgery. CONCLUSION: Compared with valve replacement alone, the addition of the maze procedure was associated with a reduction in thromboembolic complications and improvements in hemodynamic performance in patients undergoing mechanical valve replacement, particularly in those with low risk of surgery.

Urologic robot-assisted laparoendoscopic single-site surgery using a homemade single-port device: a single-center experience of 68 cases.

PURPOSE: To describe our experience with robot-assisted laparoendoscopic single-site (R-LESS) surgeries and evaluate a homemade port system as an effective access technique. PATIENTS AND METHODS: Between May 2009 and April 2010, 68 consecutive R- LESS urologic operations were performed in our institution. A 4 to 5 cm long incision was made over the umbilicus. After the inner ring of the Alexis wound retractor was placed into the peritoneum, a common size 7 surgical glove was then applied over the external side of the wound retractor. A homemade single port was established by inserting two 12-mm trocars and two 8-mm trocars through fingers of a surgical glove and securing it to the port. RESULTS: Sixty-eight patients underwent R-LESS, including partial nephrectomy in 51, nephroureterectomy in 12, radical nephrectomy and adrenalectomy in 2 each, and simple nephrectomy in 1. Mean patient age was 56 years (range 16-81 y). Mean body mass index was 23.9 kg/m(2) (range 17.2-32.9 kg/m(2)). The mean operative time was 219 minutes (range 109-382 min). Mean estimated blood loss 319 mL (range 50-1550 mL), and change in hematocrit was 5.2 % (range 0.0-14.8%). At a mean follow-up of 8 months, there were no port-related complications, and cosmesis was excellent. CONCLUSIONS: R-LESS is feasible and can be safely applied to a variety of urologic operations, considering the low intraoperative complication rate. Our homemade single-port device provides adequate range of motion and is more flexible in port placement for R-LESS than the current multichannel port.