Optimal pulmonary artery perfusion mode and perfusion pressure during cardiopulmonary bypass

AIM

Reducing lung injury during cardiopulmonary bypass (CPB) is important for patients' recovery. The present study was designed to evaluate the effects of pulmonary artery perfusion pressure on the extent of lung injury during CPB in an animal model.

METHODS

Twenty healthy mongrel dogs were randomly divided into four groups, including a control group and three perfusion groups designed to simulate clinical cardiopulmonary bypass-induced lung injury. During pulmonary ischemia and cardiopulmonary bypass, protective perfusions were performed using different perfusion pressures (15-20, 25-30, and 40-45 mmHg), while animals in the control group were not perfused. After pulmonary reperfusion, the changes in pulmonary function and tissue histopathology were determined.

RESULTS

Compared with the control group, lung compliance, oxygenation and vascular resistance after reperfusion were significantly improved in both low- and moderate-pressure groups. The malonaldehyde concentration, neutrophil sequestration ratio, and expression of ICAM-1 were also decreased significantly in the two groups. However, there were no significant differences in any of these parameters between the control group and the high-pressure group. Histopathological examination demonstrated that there were obvious inflammatory cell infiltration and tissue damage in the control and high-pressure groups, which was prevented in the low- and moderate-pressure groups.

CONCLUSION

The perfusion pressure is an important factor that determines the extent of lung protection, and the use of pressures below 30 mmHg is optimal, with the safest and most effective range being 15-20 mmHg.

Improving the capacitive deionisation performance by optimising pore structures of the electrodes

In this paper, three types of ordered mesoporous carbons (OMCs) were synthesised by an original template method and a modified sol-gel process involving nickel salts. The effects of pore arrangement pattern (ordered and random), and pore size distribution (mesoporous and microporous) on the desalination performance were investigated by comparing mesoporous carbons with activated carbons (ACs). It is found that the mesoporous carbons prepared by addition of nickel salts demonstrated higher specific capacitances than mesoporous carbons without nickel salts and the activated carbon electrodes. Their electrosorptive deionisation properties were also compared in a dilute NaCl solution (conductivity 100 microS cm(-1)), the amount of adsorbed ions are measured by a flow though apparatus in the laboratory. It is found that the amounts of the adsorbed ions are 15.9 micromol g(-1) for OMCs involving nickel in the synthesis process, 10.3 micromol g(-1) for OMC not involving nickel salts and 4.7 micromol g(-1) for ACs.

A common gain of function of p53 cancer mutants in inducing genetic instability

The critical tumor suppressor p53 is mutated in over half of all human cancers. The majority of p53 cancer mutations are missense mutations, which can be classified into contact mutations that directly disrupt the DNA-binding of p53 but have modest impact on p53 conformation and structural mutations that greatly disrupt p53 conformation. Many p53 cancer mutants, including the hot spot mutations (R175H, R248W and R273H), not only lose p53-dependent tumor-suppressor activities, but also acquire new oncogenic activities to promote cancer. Therefore, it is critical to elucidate the gain of oncogenic function of p53 cancer mutants. Using humanized p53-mutant knock-in mouse models, we have identified a gain of oncogenic function shared by the most common p53 contact mutants (R273H and R248W) and structural mutant (R175H). This gain of function inactivates Mre11/ATM-dependent DNA damage responses, leading to chromosomal translocation and defective G(2)/M checkpoint. Considering the critical roles of ATM in maintaining genetic stability and therapeutic responses to many cancer treatments, the identification of this common gain of function of p53 cancer mutants will have important implication on the drug resistance of a significant portion of human cancers that express either the contact or structural p53 cancer mutants.

Energy and momentum deposited into a QCD medium by a jet shower

For a hard parton moving through a dense QCD medium, we compute self-consistently the energy loss and the fraction deposited into the medium due to showering and rescattering of the shower, assuming weak coupling between probe and medium. The same transport coefficients thus determine both the energy loss and its deposition into the medium. This allows a parameter free calculation of the latter once the former are computed or measured. We compute them for a weakly interacting medium. Assuming a short thermalization time for the deposited energy, we determine the medium's hydrodynamical response and obtain a conical pattern that is strongly enhanced by showering.

Cell cycle genes and ovarian cancer susceptibility: a tagSNP analysis

Background:

Dysregulation of the cell cycle is a hallmark of many cancers including ovarian cancer, a leading cause of gynaecologic cancer mortality worldwide.

Methods:

We examined single nucleotide polymorphisms (SNPs) (n=288) from 39 cell cycle regulation genes, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors, in a two-stage study. White, non-Hispanic cases (n=829) and ovarian cancer-free controls (n=941) were genotyped using an Illumina assay.

Results:

Eleven variants in nine genes (ABL1, CCNB2, CDKN1A, CCND3, E2F2, CDK2, E2F3, CDC2, and CDK7) were associated with risk of ovarian cancer in at least one genetic model. Seven SNPs were then assessed in four additional studies with 1689 cases and 3398 controls. Association between risk of ovarian cancer and ABL1 rs2855192 found in the original population [odds ratio, OR_{BB vs AA} 2.81 (1.29–6.09), P=0.01] was also observed in a replication population, and the association remained suggestive in the combined analysis [OR_{BB vs AA} 1.59 (1.08–2.34), P=0.02]. No other SNP associations remained suggestive in the replication populations.

Conclusion:

ABL1 has been implicated in multiple processes including cell division, cell adhesion and cellular stress response. These results suggest that characterization of the function of genetic variation in this gene in other ovarian cancer populations is warranted.

Loss of Nkx3.1 leads to the activation of discrete downstream target genes during prostate tumorigenesis

The expression of NKX3.1, a transcriptional regulator and tumor suppressor gene in prostate cancer, is downregulated during early stages of prostate tumorigenesis. However, little is known of the alterations in gene expression that occur as a result of this event. We combined laser capture microdissection and gene expression profiling to analyze the molecular consequences of Nkx3.1 loss during prostate cancer initiation using Nkx3.1-deficient mice. This analysis identified a cohort of genes (loss-of-Nkx3.1 signature) that are aberrantly overexpressed during loss-of-Nkx3.1 driven tumor initiation. We studied the expression of these same genes in independent loss-of-Pten and c-myc overexpression prostate adenocarcinoma mouse models. Nkx3.1 expression is lost in prostate epithelial proliferation in both of these mouse models. However, Nkx3.1 loss is an early event of tumor development in the loss-of-Pten model, whereas it occurs at later stages in c-myc transgenic mice. A member of genes of the loss-of-Nkx3.1 signature, like clusterin and quiescin Q6, are highly expressed in prostatic hyperplasia and intraepithelial neoplasia (PIN) lesions that also lack Nkx3.1 in the Pten-deficient prostate, but not in similar lesions in the c-myc transgenic model. Meta-analysis of multiple prostate cancer gene expression datasets including those from loss-of-Nkx3.1, loss-of-Pten, c-myc overexpression, and constitutively active Akt prostate cancer models, further confirmed that genes associated with the loss-of-Nkx3.1 signature integrate with Pten-Akt signaling pathways, but do not overlap with molecular changes associated with the c-myc signaling pathway. In human prostate tissue samples, loss of NKX3.1 expression and corresponding clusterin overexpression are co-localized at sites of prostatic inflammatory atrophy, a possible very early stage of human prostate tumorigenesis. Collectively, these results suggest that the molecular consequences of NKX3.1 loss depend on the epithelial proliferative stage at which its expression is lost and, that alterations in the Pten-Akt-Nkx3.1 axis are important for prostate cancer initiation.