bcl-x Prevents Apoptotic Cell Death of Both Primitive and Definitive Erythrocytes at the End of Maturation

bcl-x is a member of the bcl-2 gene family, which regulates apoptotic cell death in various cell lineages. There is circumstantial evidence suggesting that bcl-x might play a role in the apoptosis of erythroid lineage cells, although there is no direct evidence. In this study, we used Bcl-X null mouse embryonic stem (ES) cells, and showed that Bcl-X is indispensable for the production of both embryonic primitive erythrocytes (EryP) and adult definitive erythrocytes (EryD) at the end of their maturation. In vivo, bcl-x−/− ES cells did not contribute to circulating EryD in adult chimeric mice that were produced by blastocyst microinjection of the bcl-x−/− ES cells. bcl-x−/− EryP and EryD were produced by in vitro differentiation induction of ES cells on macrophage colony-stimulating factor–deficient stromal cell line OP9, and further analysis was carried out. The emergence of immature EryP and EryD from bcl-x−/− ES cells was similar to that from bcl-x+/+ ES cells. However, prominent cell death of bcl-x−/− EryP and EryD occurred when the cells matured. The data show that the antiapoptotic function of bcl-x acts at the very end of erythroid maturation

Effects of MgO Catalyst on Depolymerization of Poly-L-lactic Acid to L,L-Lactide

To control the depolymerization of poly-L-lactic acid (PLLA) into L,L-lactide, effects of altering the physical and chemical properties of magnesium oxide (MgO) on its ability as a catalyst were investigated. Four kinds of MgO particles: MgO-heavy, 0.2, 0.05, and 0.01μm, were used having primary particles of different dimensions, surface areas, and chemical structures/species. Thermo-gravimetric profiles of PLLA/MgO composites shifted into a lower temperature range due to an increase in the catalytic surface area resulting from a decrease in the dimensions of the MgO particles. However, decreasing the dimensions caused frequent side reactions with unfavorable products: cyclic oligomers and meso-lactide, due to the presence of different chemical structures/species. Heat treatment of the MgO particles effectively suppressed the oligomer production and enhanced the L,L-lactide production, but also accelerated the meso-lactide production at lower temperatures. These results indicate that the surface properties of MgO considerably influence the depolymerization of PLLA, with the catalytic behavior of MgO controllable by heat treatment and selection of the depolymerization conditions

Racemization Behavior of L,L-Lactide during Heating

To control the depolymerization process of poly (L-lactic acid) into L,L-lactide for feedstock recycling, the racemization of L,L-lactide as a post-depolymerization reaction was investigated. In the absence of a catalyst, the conversion to meso-lactide increased with increase in the heating temperature and time at a higher rate than the conversion into oligomers. The resulting high composition of meso-lactide suggests that the direct racemization of L,L-lactide had occurred in addition to the known racemization mechanism that occurs on the oligomer chains. In the presence of MgO, the oligomerization rapidly proceeded to reach an equilibrium state between monomers and oligomers. The equilibrium among L,L-, meso-, and D,D-lactides was found to be a convergent composition ratio: L,L-:meso-:D,D-lactides = 1:1.22:0.99 (wt/wt/wt) after 120 min at 300 °C. This composition ratio also indicates that, in addition to the known racemization reaction on the oligomer chains, direct racemization among the lactides is also a frequent occurrence

Response of the Cutworm Spodoptera litura to Sesame Leaves or Crude Extracts in Diet

The effects of extracts of sesame, Sesamum indicum L. (Liamiales: Pedaliaceae), and whole leaves of some selected cultivars of sesame were tested using a natural host Spodoptera litura (F.) (Lepidoptera: Noctuidae). Indices taken using the immature stages include; diet utilization, growth and development and induction of detoxification enzymes. The results indicate that S. litura generally selects its food amongst cultivars within 6 hours after food presentation. Growth and development of the insect is controlled also by plant acceptability and quality. Although all the cultivars tested significantly limit insect growth and development the variety 56S-radiatum did not allow a complete life cycle as pupation from first instar stage was 0%. Generally the crucial period for immature S. litura was the larval period, especially the first two instars where the weight of an insect fed on an experimental diet was three times lower than that of a control diet. The larval developmental period was greater than 40 days as compared to 17 days for insects fed a control diet. S. litura also had lowered efficiency in utilizing ingested food, from a low of 13% in a sesame cultivar to 45% in the control diet. The key detoxification enzyme was a glutathione s-transferase that was confirmed by a 6-fold increase between S. litura fed a plant cultivar vs. a control diet towards the substrate 1,2-dichloro-4-nitrobenzene. First and second instars of S. litura have a relatively reduced detoxification of enzymes in response to plant cultivar diets leading to low survival. A 3% v/w crude extract of the cultivars increased enzyme induction towards all the tested substrates

Reconditioning lungs donated after cardiac death using short-term hypothermic machine perfusion.

Background: Hypothermic machine perfusion (HMP) is widely used to preserve kidneys and livers for transplantation. This study investigated whether short-term HMP could improve the quality of lungs donated after cardiac death (DCD). Methods: In a clinically relevant uncontrolled DCD model, beagles were divided into two groups (n=5 each): 4 hr warm ischemia + 14 hr static cold storage (SCS group) or 4 hr warm ischemia + 12 hr SCS followed by 2 hr HMP (HMP group). HMP was performed using centrifugal perfusion with STEEN solution at approximately 10°C. In both groups, the left lungs were then transplanted and reperfused for 4 hr to evaluate the posttransplantation lung functions. Results: HMP was performed safely, not inducing any oxidative damage. The dynamic pulmonary compliance was stable during HMP, whereas the pulmonary vascular resistance significantly decreased. HMP microscopically eliminated residual microthrombi in the donor lungs just before transplantation. The lung tissue adenosine triphosphate levels 4 hr after reperfusion were significantly higher in the HMP group compared with the SCS group. The serum malondialdehyde levels and proinflammatory cytokine levels in the bronchoalveolar lavage fluid 4 hr after reperfusion were significantly lower in the HMP group than in the SCS group. The physiologic lung functions during reperfusion were significantly better in the HMP group compared with the SCS group. HMP also significantly reduced ischemia-reperfusion injury in the microscopic findings. Conclusions: Short-term HMP could resuscitate ischemically damaged DCD lungs and ameliorate ischemia-reperfusion injury

Protective effect of pre-recovery surfactant inhalation on lungs donated after cardiac death in a canine lung transplantation model.

[Background]: Warm ischemia-reperfusion injury related to donation after cardiac death is a crucial issue in transplantation. Because surfactant function deteriorates in lungs during warm ischemia, we hypothesized pre-recovery surfactant inhalation would mitigate warm ischemia-reperfusion injury. [Methods]: We rendered donor dogs cardiac dead and left them at room temperature. All animals received ventilation for 60 minutes starting at 240 minutes after cardiac arrest. The animals were divided into 2 groups: NS (normal saline, n = 7) group, which received aerosolized normal saline, and SF (surfactant; n = 5), which received aerosolized surfactant. The lungs were flushed and procured, and the left lung was transplanted into recipient dogs. At 45 minutes of reperfusion, the right pulmonary artery was ligated, and the left transplanted lung function was evaluated. [Results]: In the NS group, 2 of 7 dogs died at 75 minutes after reperfusion, whereas all 5 animals in the SF group survived for 240 minutes after reperfusion. The SF group showed significantly better dynamic compliance, oxygenation, and wet-to-dry weight ratio. Furthermore, the SF group had higher levels of high-energy phosphates in the lung tissues and lower levels of interleukin-8, tumor necrosis factor-α, and protein in the bronchoalveolar lavage fluid. Histologically, the lungs in the SF group showed fewer signs of interstitial edema and hemorrhage and significantly less neutrophilic sequestration than those of the NS group. [Conclusions]: Our results indicated pre-recovery surfactant inhalation improved graft function, maintained adenine nucleotide levels, and prevented alveolar–capillary barrier leakage, resulting in the attenuation of warm ischemia-reperfusion injury