PTEN deletion prevents ischemic brain injury by activating the mTOR signaling pathway

It is increasingly clear that the tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a negative regulator of neuronal cell survival. However, its molecular mechanisms remain poorly understood. Here we found that PTEN/mTOR is critical for controlling neuronal cell death after ischemic brain injury. Male rats were subjected to MCAO (middle cerebral artery occlusion) followed by pretreating with bpv (pic), a potent inhibitor for PTEN, or by intra-cerebroventricular infusion of PTEN siRNA. bpv (pic) significantly decreased infarct volume and reduced the number of TUNEL-positive cells. We further demonstrated that although bpv (pic) did not affect brain injury-induced mTOR protein expression, bpv (pic) prevented decrease in phosphorylation of mTOR, and the subsequent decrease in S6. Similarly, down-regulation of PTEN expression also reduced the number of TUNEL-positive cells, and increased phospho-mTOR. These data suggest that PTEN deletion prevents neuronal cell death resulting from ischemic brain injury and that its neuroprotective effects are mediated by increasing the injury-induced mTOR phosphorylation.

Morphology and texture evolution of nanostructured CaF2 films on amorphous substrates under oblique incidence flux

The morphology and biaxial texture of vacuum evaporated CaF(2) films on amorphous substrates as a function of vapour incident angle, substrate temperature and film thickness were investigated by scanning electron microscopy, x-ray pole figure and reflection high energy electron diffraction surface pole figure analyses. Results show that an anomalous [220] out-of-plane texture was preferred in CaF(2) films deposited on Si substrates at < 200 °C with normal vapour incidence. With an increase of the vapour incident angle, the out-of-plane orientation changed from [220] to [111] at a substrate temperature of 100 °C. In films deposited with normal vapour incidence, the out-of-plane orientation changed from [220] at 100 °C to [111] at 400 °C. In films deposited with an oblique vapour incidence at 100 °C, the texture changed from random at small thickness (5 nm) to biaxial at larger thickness (20 nm or more). Using first principles density functional theory calculation, it was shown that [220] texture formation is a consequence of energetically favourable adsorption of CaF(2) molecules onto the CaF(2)(110) facet.

ERIC-PCR identification of the spread of airborne Escherichia coli in pig houses

To understand the spread of microbial aerosols in pig houses, with Escherichia coli (E. coli) as indicator, the airborne E. coli in 4 pig houses and their surroundings at different points 10, 50m upwind and 10, 50, 100, 200 and 400m downwind respectively from the pig houses were collected, and the concentrations were calculated at each sampling point. Furthermore, the feces of pigs were collected to separate E. coli. The ERIC-PCR (Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction) technology was used to amplify the isolated E. coli DNA samples, then the amplified results were analyzed by NTSYS-pc (Version 2.10) to identify the similarity of isolated E. coli. The results showed that the airborne E. coli concentrations in indoor air of the 4 pig houses (21-35CFUm(-)(3) air) were much higher than those in upwind and downwind air (P<0.05), but there were no significant differences (P>0.05) at downwind distances. The ERIC-PCR results also showed that 52.4% of the fecal E. coli (four houses being respectively 2/4, 50%; 2/4, 50%; 3/6, 50%; 4/7, 57.1%) were identical to the indoor airborne E. coli isolates, and there was more than 90% similarity between the majority of E. coli (50%, 21/42) isolated from downwind air at 10, 50, 100 and 200m and those from indoor air or feces. It could be concluded that the aerosols in pig houses can spread to the surroundings, and thus effective measures should be taken to control and minimize the spread of microbial aerosols.

Spinal Cord Injury Blunted Effects of Endothelin-1 on Ca2+ Transients and Calcium Current in Isolated Rat Cardiomyocytes

Plasma endothelin-1 (ET-1) levels are elevated in spinal cord injury (SCI), and ET-1 may be involved in the pathophysiology of this condition. However, its effects on contractile function of the heart of SCI rats are still unknown. To define more clearly the possiblel role of ET-1 following SCI, we investigated the effect of ET-1 on the contraction, calcium transients and L-type calcium current (ICa,L) in the cardiomyocytes of control and SCI rats. Sixteen Sprague-Dawley male rats aged 80-100 days and weighing 250-350 g were randomized into control and SCI groups. Fourteen days following compression injury to the spinal cord, effects of ET-1 on the contraction, calcium transients and ICa,L were studied in the cardiomyocytes of control and SCI rats by the technique of simultaneous measurement of intracellular Ca2+ and contraction and by whole-cell configuration of the patch-clamp technique. In myocytes from control rats, ET-1 significantly increased contraction, the magnitude of Ca2+ transients and the peak amplitude of ICa,L. However, ET-1 had little effect on the amplitude of contraction, calcium transients and ICa,L in myocytes from SCI rats. These results suggest that the positive inotropic effects of ET-1 on control myocardial contraction may be altered in pathological states such as SCI.

Length of time of embryo storage does not negatively influence pregnancy rates after thawing and transfer

PURPOSE

To determine if longer storage of embryos in a cryopreserved state negatively affects the chance of successful implantation following thawing and transfer.

METHODS

A retrospective cohort analysis of frozen-thawed embryos that had been donated to recipients. Four time periods were evaluated.

RESULTS

No significant decrease in pregnancy or implantation rates was found in the longest freezing group (> or =6 years). In fact, if there was a trend, it was for improved pregnancy rates with longer storage. One of the successes was from embryos stored about 12 years.

CONCLUSIONS

Hopefully these data and results from other IVF centers will influence those countries having a mandatory discarding policy to reconsider and lift these restrictions, especially to increase the pool of embryos available for donation.

Cryopreservation of blastocysts using a modification of a simplified freezing protocol with a one step removal of cryoprotectant successfully used previously to freeze 2 pronuclear or multi-cell embryos

PURPOSE

To describe a modification of a simplified freezing protocol for the cryopreservation of blastocysts.

METHODS

1.5 M glycerol was substituted as a cryoprotectant instead of propanediol.

RESULTS

There was a survival rate of 59.1% (13/22) with three live deliveries in seven transfers (42.9% per transfer). The implantation rate was 28.6% (4/14).

CONCLUSIONS

This is the first description of a new technique for freezing blastocysts. A larger series is needed to determine if the good pregnancy rates will continue.

REP-PCR tracking of the origin and spread of airborne Staphylococcus aureus in and around chicken house

Staphylococcus aureus was used as an indicator to study the origin and spread of microbial aerosol in and around chicken houses. Air samples indoor, upwind (10 and 50 m), and downwind (10, 50, 100, 200, and 400 m) of four chicken houses were collected using Andersen-6 stages sampler. The concentrations of S. aureus were determined for every sample site. Isolation of S. aureus from chicken feces was performed according to the standard method. The genetic relationship among the isolates was determined by profiles of PCR-amplified repetitive extragenic palindromic (REP-PCR) elements. The results showed that the concentrations of S. aureus indoor of four chicken houses were higher than those upwind and downwind sites (P < 0.05 or P < 0.01), but there were no significant concentration differences among downwind sites (P > 0.05). The fingerprints and the phylogenetic tree indicated that a part of the S. aureus (55.6%, 10/18) isolates from indoor air had the same REP-PCR fingerprints as feces isolates. Consequently, most isolates (57.1%, 20/35) from downwind 10, 50, 100, 200, even 400 m had the same REP-PCR fingerprints as those from indoor or feces. These data indicated that some isolates from downwind and indoor originated from the chicken feces. However, those isolates from upwind had low similarity (similarity index 0.6-0.87) to those from indoor or feces. Therefore, the isolates upwind were not from the chicken feces or indoor. These results suggest that microbes in chicken feces can be aerosolized and spread indoor and outdoor, especially to downwind of the chicken houses. It should have an important epidemiological and public health significance.

PRACTICAL IMPLICATIONS

Thus, the use of S. aureus as an indicator to study the origin and spread of airborne pathogens from chicken houses is potentially useful for enhancing public health and understanding the airborne epidemiology of this pathogen. Meanwhile it can provide evidence for studying the spreading model of airborne pathogens.

Anisotropic diffusion properties in infants with hydrocephalus: a diffusion tensor imaging study

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) can noninvasively detect in vivo white matter (WM) abnormalities on the basis of anisotropic diffusion properties. We analyzed DTI data retrospectively to quantify the abnormalities in different WM regions in children with hydrocephalus during early infancy.

MATERIALS AND METHODS

Seventeen infants diagnosed with hydrocephalus (age range, 0.13-16.14 months) were evaluated with DTI and compared with 17 closely age-matched healthy children (age range, 0.20-16.11 months). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity values in 5 regions of interest (ROIs) in the corpus callosum and internal capsule were measured and compared. The correlation between FA and age was also studied and compared by ROI between the 2 study groups.

RESULTS

Infants with hydrocephalus had significantly lower FA, higher MD, and higher radial diffusivity values for all 3 ROIs in the corpus callosum, but not for the 2 ROIs in the internal capsule. In infants with hydrocephalus, the increase of FA with age during normal development was absent in the corpus callosum but was still preserved in the internal capsule. There was also a significant difference in the frequency of occurrence of abnormal FA values in the corpus callosum and internal capsule.

CONCLUSIONS

This retrospective DTI study demonstrated significant WM abnormalities in infants with hydrocephalus in both the corpus callosum and internal capsule. The results also showed evidence that the impact of hydrocephalus on WM was different in the corpus callosum and internal capsule.

Rap1b is critical for glycoprotein VI-mediated but not ADP receptor-mediated alpha2beta1 activation

BACKGROUND

The platelet alpha2beta1 integrin functions as both an adhesion and signaling receptor upon exposure to collagen. Recent studies have indicated that alpha2beta1 function can be activated via inside-out signaling, similar to the prototypical platelet integrin alphaIIbbeta3. However, signaling molecules that regulate alpha2beta1 activation in platelets are not well defined. A strong candidate molecule is the small GTPase Rap1b, the dominant platelet isoform of Rap1, which regulates alphaIIbbeta3 activation.

OBJECTIVES

We hypothesized that Rap1b positively regulates alpha2beta1 during agonist-induced platelet activation.

METHODS

To test whether Rap1b activates alpha2beta1 downstream of glycoprotein (GP)VI or other platelet receptors, we stimulated platelets purified from Rap1b-/- or wild-type mice with diverse agonists and measured alpha2beta1 activation using fluorescein isothiocyanate-labeled monomeric collagen. We also examined the role of Rap1b in outside-in signaling pathways by analyzing adhesion and spreading of Rap1b-/- or wild-type platelets on monomeric, immobilized collagen. Finally, we monitored the activation status of related Rap GTPases to detect changes in signaling pathways potentially associated with Rap1b-mediated events.

RESULTS

Rap1b-/- platelets displayed comparable ADP-induced or thrombin-induced alpha2beta1 activation as wild-type platelets, but reduced convulxin-dependent alpha2beta1 activation. Rap1b-/- platelets exhibited increased spreading on immobilized collagen but similar adhesion to immobilized collagen compared to wild-type platelets. Rap1b-/- platelets also showed Rap1a and Rap2 activation upon agonist stimulation, possibly revealing functional compensation among Rap family members.

CONCLUSIONS

Rap1b is required for maximal GPVI-induced but not ADP-induced activation of alpha2beta1 in murine platelets.

Polymorphisms in the interleukin 3 gene show strong association with susceptibility to Graves' disease in Chinese population

Graves' disease (GD) is a common organ-specific autoimmune disorder, which is multifactorial and develops in genetically susceptible individuals. We had earlier mapped a susceptibility locus for GD to chromosome 5q31-33 in a linkage study. Here we used tag single-nucleotide polymorphisms (SNPs) to search for genetic variants associated with GD, and examined 19 functional candidate genes in this chromosomal region. We identified 192 polymorphisms by re-sequencing the candidate genes, and selected 51 tagSNPs to genotype in a case-control collection of 1118 south Han Chinese subjects (428 cases and 690 controls). Initial analysis suggested that a non-synonymous SNP rs40401 (P27S) of interleukin 3 (IL3) was associated with GD, and further fine-mapping showed that rs40401, or its perfect proxy SNP rs31480 in the 5' flanking region of IL3, fully accounted for the association signal at this locus. We replicated significant association of rs40401 with GD in an independent sample collection of 839 north Han Chinese subjects. A combined analysis revealed strong validation of this association (odds ratio (OR(common))=1.63, combined P (P(comb))=4 x 10(-6) in the Recessive disease model). This study provides convincing evidence that the IL3 gene is a susceptibility locus for GD in the Chinese population.

Effect of the degree of fragmentation on embryo survival after freeze-thawing

PURPOSE

To determine if the degree of fragmentation of embryos prior to freezing correlate in a negative manner with survival after thawing.

METHODS

A retrospective review of frozen embryos thawed for purposes of embryo transfer was done. Survival and transferability rates were determined according to degree of fragmentation.

RESULTS

The chance that an embryo with < 25% fragmentation was deemed good enough for transfer upon thawing was 63.6% compared to 52.8% for embryos > 25% (p < .05).

CONCLUSIONS

Though more fragmented embryos have a lower survival rate after freeze thawing, about 50% of embryos with > 25% fragmentation will still survive the thaw and be able to be transferred.

Comparison of the efficacy of selecting sperm with normal nuclei by high magnification for intracytoplasmic sperm injection (ICSI) according to age in refractory in vitro fertilization (IVF) cases

PURPOSE

To determine the pregnancy rates according to age in women failing to conceive after three previous embryo transfers or having a husband whose sperm shows a DNA fragmentation index (DFI) > 30% when performing the sperm chromatin structure assay.

METHODS

Women up to age 45 were included and there was no restriction for low egg reserve. Live delivered pregnancy rates were determined according to three age groups: < or =34, 35-38, 39-45. The data were also analyzed in a group comparable to previous publications using high magnification ICSI, i.e., younger women with normal egg reserve. Pregnancy rates following frozen embryo transfer were also evaluated.

RESULTS

Using all 86 in vitro fertilization-embryo transfer (IVF-ET) cycles the live delivered pregnancy rates were 40% (10/25) for women < or = age 34, 24% (6/25) in women age 35-38, and 13.8% in women aged 39-45. Evaluating the younger group with normal egg reserve with > or =3 previous failed IVF-ET cycles the live delivered pregnancy rate per transfer was 38% (16/42). If one adds the additional six live deliveries from subsequent frozen embryo transfer (6 of 17, 35.3%) this group of women had a 52.3% (22/42) live delivered pregnancy rate from one egg retrieval.

CONCLUSIONS

These data were uncontrolled and thus conclusions should be viewed with caution. The results are sufficiently encouraging to warrant a prospective controlled trial and possibly encourage a company to consider commercially manufacturing high magnification microscopes.

A comparison of efficacy of freezing embryos at the 2 pronuclear (2PN) stage vs multi-cell when using a simplified freezing protocol with one-step removal of cryoprotectant

PURPOSE

To compare the efficacy of freezing embryos at the 2 pronuclear stage vs multi-cell stage using a simplified freezing protocol with a one-step removal of the cryoprotectant.

METHODS

A retrospective analysis was performed. Survival, delivered pregnancy and implantation rates were compared in transfers of all embryos frozen at 2 pronuclear stage (2PN) or all embryos frozen at multi-cell stage. The results were further stratified and compared according to the number of high quality embryos transferred.

RESULTS

In all categories despite comparing similar numbers and quality of embryos transferred there was a significantly higher survival rate of 2PN embryos. Significantly higher delivered pregnancy and implantation rates were seen with 2PN vs multi-cell embryos when there was only one or two embryos with > or = 6 blastomeres and < 25% fragmentation, and a trend for higher delivered pregnancy rates when there were three top quality embryos transferred.

CONCLUSIONS

When given the option it is preferable when using this simplified freezing and thawing protocol to freeze at the 2PN stage.

Pregnancy rates per embryo transfer (ET) may be improved by conventional oocyte insemination for male factor rather than intracytoplasmic sperm injection (ICSI)

PURPOSE

To determine if intracytoplasmic sperm injection (ICSI) for mild male factor may create embryos less likely to implant.

METHOD

A retrospective analysis of pregnancy outcome following oocyte fertilization with ICSI vs conventional egg insemination was performed.

RESULTS

Though there were many less cases using conventional oocyte insemination compared to ICSI so that a meaningful comparison of outcome could not be made, the data could suggest the fertilization by ICSI might result in embryos less likely to implant.

CONCLUSIONS

This pilot study should encourage IVF centers to consider conventional oocyte insemination for mild male factor instead of ICSI. Only by evaluating a larger series can it be determined with certainty that fertilization by ICSI may lower the implantation potential of the embryo that is formed.

The effect of blastomere number on embryo survival upon freezing/thawing

PURPOSE

To determine if the blastomere number of embryos at the time of freezing is related to its quality post-thaw.

METHODS

A retrospective cohort analysis of frozen/thawed embryos. Only multi-cell embryos were used for this study. If an embryo was of good quality it would either be transferred or re-frozen.

RESULTS

There did not appear to be any trend for a lower percentage of good quality embryos with fewer numbers of blastomeres.

CONCLUSIONS

Though 4-cell embryos have a markedly lower implantation potential upon fresh embryo transfer compared to 6-8-cell embryos, this is not reflected in their ability to survive freeze-thawing.