Effects of a synthetic PEG-ylated Tie-2 agonist peptide on endotoxemic lung injury and mortality

A synthetic 7-mer, HHHRHSF, was recently identified by screening a phage display library for binding to the Tie-2 receptor. A polyethylene-oxide clustered version of this peptide, termed vasculotide (VT), was reported to activate Tie-2 and promote angiogenesis in a mouse model of diabetic ulcer. We hypothesized that VT administration would defend endothelial barrier function against sepsis-associated mediators of permeability, prevent lung vascular leakage arising in endotoxemia, and improve mortality in endotoxemic mice. In confluent human microvascular endothelial cells, VT prevented endotoxin-induced (lipopolysaccharides, LPS O111:B4) gap formation, loss of monolayer resistance, and translocation of labeled albumin. In 8-wk-old male C57Bl6/J mice given a ～70% lethal dose of endotoxin (15 mg/kg ip), VT prevented lung vascular leakage and reversed the attenuation of lung vascular endothelial cadherin induced by endotoxemia. These protective effects of VT were associated with activation of Tie-2 and its downstream mediator, Akt. Echocardiographic studies showed only a nonsignificant trend toward improved myocardial performance associated with VT. Finally, we evaluated survival in this mouse model. Pretreatment with VT improved survival by 41.4% (n = 15/group, P = 0.02) and post-LPS administration of VT improved survival by 33.3% (n = 15/group, P = 0.051). VT-mediated protection from LPS lethality was lost in Tie-2 heterozygous mice, in agreement with VT's proposed receptor specificity. We conclude that this synthetic Tie-2 agonist, completely unrelated to endogenous Tie-2 ligands, is sufficient to activate the receptor and its downstream pathways in vivo and that the Tie-2 receptor may be an important target for therapeutic evaluation in conditions of pathological vascular leakage.     

L’utilisation du MSOME: expérience de six ans

Introduction

MSOME (Motile Sperm Organellar Morphology Examination) is a new method for real-time evaluation of sperm morphology under 6600x high magnification. ICSI modified procedure with sperm selected by MSOME is named IMSI (Intracytoplasmic Morphologically Selected sperm Injection). IMSI has been developed to improve ongoing pregnancy rate in couples with repeated implantation failure.

Material and methods

The study concern an observational cohort of 11535 ICSI performed with fresh ejaculated sperm in our ART lab between January 2004 and July 2009. Among them, 2509 were realized with IMSI. The primary outcome measures were cleavage rate per injected oocyte on day 2, clinical pregnancy and abortion rates. Comparisons were performed using Chi square² test and univariate analysis of variance.

Results

There were no significant difference between conventional ICSI and IMSI groups in term of cleavage and pregnancy rates. Couples with abnormal sperm (teratozoospermia, oligozoospermia and oligoteratozoospermia) and no previous ICSI failure, had a significantly higher clinical pregnancy with IMSI than with ICSI (34.4% vs. 27.1%, p = 0.02). Furthermore, pregnancies obtained in patients with teratozoospermia were associated with a lower abortion rate after IMSI than after ICSI, close to significance (12.6% vs. 19.6%, p = 0.08).

Conclusion

In cases of severe teratozoospermia, IMSI appears to improve pregnancy rate and pregnancy outcome.     

Prolactin-induced cytologic changes in the mucosa of the pigeon crop during crop-“milk” formation

Summary Light and electron microscope observations reveal two basic histo- and cytologic changes which take place in the pigeon crop during the course of prolaction administration to both sexes; (1) an increase in mitotic activity resulting in hyperplasia of the lateral lobes of the crop and (2) the accumulation of lipid in cells of these lobes. The latter process begins about twelve hours following prolactin injection. Histologic and cytochemical tests, as well as thin layer chromatographic analysis, reveal that these lipids may be classified as neutral unsaturated triglycerides. Tissues of control and prolactin-treated groups examined during the course of this study do not reveal any striking changes in organelle systems — aside from the accumulation of large lipid droplets. It does appear, however, that while ribosomes exist primarily as single units in non-stimulated cells, they appear primarily as polysomes in stimulated cells actively engaged in lipid synthesis. The origin of the cytoplasmic lipid inclusions is of interest. Morphologic evidence suggests that (1) they are not the result of cyto-pathologic changes, (2) they do not result from mitochondrial transformation and (3) they are not incorporated as discrete triglyceride micelles into these cells. The availability of precursors to the cell is dicussed in light of the observation that intercellular channels increase in width, and microvilli and desmosomes decrease in number throughout the experimental series. The incorporation of possible precursors into the cytoplasm may occur via two distinct classes of vesicles. One class is thought to arise through micropinocytotic activity. These vesicles have filamentous boundaries which are thought to render them specific for certain classes of compounds. The second class is somewhat larger in size and differs morphologically from micropinocytotic vesicles. These are thought to arise by the fusion of tips of microvilli and the plasma membrane, thus inpounding and internalizing materials from the intercellular canals into the cytoplasm.The author is indebted to Dr. Everett Anderson for his valuable criticism and encouragement offered during the course of this work. The investigation was supported in part by a Pre-Doctoral Fellowship (1-F1-GM-20, 296-01) from the National Institutes of Health and in part by grant GM-08776 from the National Institutes of Health awarded to Dr. Everett Anderson.     

Functional implications of squamosal suture size in paranthropus boisei

It has been hypothesized that the extensively overlapping temporal and parietal bones of the squamosal sutures in Paranthropus boisei are adaptations for withstanding loads associated with feeding. Finite element analysis (FEA) was used to investigate the biomechanical effects of suture size (i.e., the area of overlap between the temporal and parietal bones) on stress, strain energy, and strain ratio in the squamosal sutures of Pan troglodytes and P. boisei (specimen OH 5) during biting. Finite element models (FEMs) of OH 5 and a P. troglodytes cranium were constructed from CT scans. These models contain sutures that approximate the actual suture sizes preserved in both crania. The FEM of Pan was then modified to create two additional FEMs with squamosal sutures that are 50% smaller and 25% larger than those in the original model. Comparisons among the models test the effect of suture size on the structural integrity of the squamosal suture as the temporal squama and parietal bone move relative to each other during simulated premolar biting. Results indicate that with increasing suture size there is a decreased risk of suture failure, and that maximum stress values in the OH 5 suture were favorable compared to values in the Pan model with the normal suture size. Strain ratios suggest that shear is an important strain regime in the squamosal suture. This study is consistent with the hypothesis that larger sutures help reduce the likelihood of suture failure under high biting loads. Am J Phys Anthropol 153:260–268, 2014. © 2013 Wiley Periodicals, Inc.     

Increased xerotolerance of Saccharomyces cerevisiae during an osmotic pressure ramp over several generations

Although mechanisms involved in response of Saccharomyces cerevisiae to osmotic challenge are well described for low and sudden stresses, little is known about how cells respond to a gradual increase of the osmotic pressure (reduced water activity; a_w) over several generations as it could encounter during drying in nature or in food processes. Using glycerol as a stressor, we propagated S. cerevisiae through a ramp of the osmotic pressure (up to high molar concentrations to achieve testing-to-destruction) at the rate of 1.5 MPa day^-1 from 1.38 to 58.5 MPa (0.990–0.635 a_w). Cultivability (measured at 1.38 MPa and at the harvest osmotic pressure) and glucose consumption compared with the corresponding sudden stress showed that yeasts were able to grow until about 10.5 MPa (0.926 a_w) and to survive until about 58.5 MPa, whereas glucose consumption occurred until 13.5 MPa (about 0.915 a_w). Nevertheless, the ramp conferred an advantage since yeasts harvested at 10.5 and 34.5 MPa (0.778 a_w) showed a greater cultivability than glycerol-shocked cells after a subsequent shock at 200 MPa (0.234 a_w) for 2 days. FTIR analysis revealed structural changes in wall and proteins in the range 1.38–10.5 MPa, which would be likely to be involved in the resistance at extreme osmotic pressure.     

Identification of microtubule growth deceleration and its regulation by conserved and novel proteins

Microtubules (MTs) are cytoskeletal polymers that participate in diverse cellular functions, including cell division, intracellular trafficking, and templating of cilia and flagella. MTs undergo dynamic instability, alternating between growth and shortening via catastrophe and rescue events. The rates and frequencies of MT dynamic parameters appear to be characteristic for a given cell type. We recently reported that all MT dynamic parameters vary throughout differentiation of a smooth muscle cell type in intact Caenorhabditis elegans. Here we describe local differences in MT dynamics and a novel MT behavior: an abrupt change in growth rate (deceleration) of single MTs occurring in the cell periphery of these cells. MT deceleration occurs where there is a decrease in local soluble tubulin concentration at the cell periphery. This local regulation of tubulin concentration and MT deceleration are dependent on two novel homologues of human cylicin. These novel ORFs, which we name cylc-1 and -2, share sequence homology with stathmins and encode small, very basic proteins containing several KKD/E repeats. The TOG domain–containing protein ZYG-9^TOGp is responsible for the faster polymerization rate within the cell body. Thus we have defined two contributors to the molecular regulation for this novel MT behavior.