Relationship between PMI and relative expression of myocardial various RNAs in rats died of different causes / 法医学杂志

OBJECTIVE@#To observe the changes of relative expression of myocardial various RNAs in rats died of different causes and their relationship with PMI.@*METHODS@#The rat models were established in which the rats were sacrificed by broken neck, asphyxia, and hemorrhagic shock. Total RNAs were extracted from myocardium. The quantitative real time PCR was used to calculate threshold cycle values of RNAs including glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-actin, inducible nitric oxide synthase (iNOS), hypoxia-inducible factor-1 (HIF-1), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and U6 small nuclear RNA (U6 snRNA) and to study the changes of the relative expressions of various indexes with PMI.@*RESULTS@#U6 snRNA with stable expression level could be used as appropriate internal control. In the early PMI, the relative expression of GAPDH, HIF-1, iNOS, TNF-alpha, and IL-6 more characteristically increased in groups of asphyxia and hemorrhagic shock than in group of broken neck, but the quantity of beta-actin decreased in all groups. In the late PMI, all the relative expressions significantly declined in correlation with the degradation of RNA.@*CONCLUSION@#The characteristic changes of each RNA expression can be used as references to estimate PMI in deaths by different causes.

Effect of glutathione on blood coagulation function / 中国实验血液学杂志

The purpose of this study was to investigate the effect of glutathione (GSH) on blood coagulation. The normal plasma samples and mixed plasma samples were taken randomly, and into which the normal dose and different concentration of GSH were added. The prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) and thrombin time (TT) were detected by using coagulation method before and after treatment with GSH. The detection results of normal plasma and mixed plasma containing GSH of different concentration were compared and analyzed with linear regression. The results showed that the APTT and FIB values of the plasma containing 2.5 mg/L glutathione or more, PT values of the plasma containing 10 mg/L glutathione or more, and TT values of the plasma containing 1250 mg/L glutathione or more were significantly different from those results of normal plasma or mixed plasma (P < 0.01) . There was a linear relation between all of the detection results of PT,APTT, FIB, TT and glutathione concentrations. The results of TT, APTT, PT and FIB detection in patient plasma were statistically different (P < 0.01) before and after treatment with normal concentration GSH. It is concluded that glutathione can influence detection results of coagulation function.

Secreted cyclophilin A induction during embryo implantation in a model of human trophoblast-endometrial epithelium interaction.

OBJECTIVE: Embryo implantation in the human is a complex process that is crucial for a successful pregnancy. Implantation involves complex interactions between the embryo and the maternal endometrium. In order to understand the critical events involved in human embryo implantation, we established a human trophoblast-endometrial interaction model to study the putative alterations of gene expression during implantation. STUDY DESIGN: Comparative proteomic analysis was applied to the co-culture and separated culture systems of the trophoblast cell line BeWo and human endometrial epithelial cell (EEC) line RL95-2. Comparing the secreted molecules resulted in an interesting finding that secreted cyclophilin A (CypA) was increased in the co-culture system. To further verify our observation, human recombinant CypA was applied to endometrial cells to understand the downstream gene regulation. RESULTS: Cyclophilin A (CypA) was identified by MALDI-TOF Mass with higher expression levels in the co-cultured cells when compared to the endometrial cells alone. Western blot analysis further confirmed the increased expression of CypA in co-culture conditions. Immunoblotting analysis showed that both p38 MAPK and extracellular signal-regulated kinase (ERK) were activated in EEC. CONCLUSION: Our results suggest that the secreted CypA plays a specific role in the signaling pathway of embryo implantation. The identification of CypA opens a new avenue for early embryo implantation research.

The polyglutamine-expanded protein ataxin-3 decreases bcl-2 mRNA stability.

Machado-Joseph disease/Spinocerebellar ataxia type 3 is an autosomal dominant neurodegenerative disease caused by polyglutamine-expanded ataxin-3. In this study, COS7-MJD26-GFP and COS7-MJD78-GFP cells, which were stably transfected with GFP-tagged full-length MJD gene with either 26 or 78 glutamine repeat, were used to demonstrate that both protein and mRNA levels of bcl-2 are decreased in the presence of expanded ataxin-3. However, the promoter activity in COS7-MJD78-GFP cells is much higher than that in COS7-MJD26-GFP, suggesting that the decrease of bcl-2 expression may be due to defects in mRNA stability. Therefore, 5,6-dichloro-benzimidazole 1-beta-D-ribofuranoside, an adenosine analogue to inhibit mRNA synthesis, was used to estimate the bcl-2 mRNA degradation rate. Our results demonstrated that bcl-2 mRNA decay in COS7-MJD78-GFP cells is about 3.5-fold faster than that in COS7-MJD26-GFP. Our study provides evidence, for the first time, that dysfunction of mRNA stability resulted from the presence of mutant ataxin-3.

Effect of radiotherapy on the thyroid of patients with nasopharyngeal cancer / 中南大学学报(医学版)

OBJECTIVE@#To determine the effect of radiotherapy on the thyroid of patients with nasopharyngeal cancer.@*METHODS@#Thyroid dynamic imaging was performed on 51 patients with nasopharyngeal cancer who had the metastasis of the jugular lymph node before and after the radiotherapy. The peak time of the thyroid artery perfusion and the constant K were obtained. The levels of free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) in the blood serum were measured at the same time.@*RESULTS@#The peak time of the left and right thyroid artery perfusion before the radiotherapy was (14.5+/-2.1)s and (15.1+/-1.9)s, respectively, while that after the radiotherapy was (19.3+/-3.2)s and (20.2+/-3.5)s, respectively. There was significant difference between the pre- and post-radiotherapy (P0.05, respectively].@*CONCLUSION@#The peak time of the thyroid artery perfusion and the constant K which reflect blood stream status after the radiotherapy are all damaged in patients with nasopharyngeal cancer. The level of FT3 and FT4 in the blood serum is dropped but the TSH level has no obvious change.

Down-regulation of heat shock protein 27 in neuronal cells and non-neuronal cells expressing mutant ataxin-3.

Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 is an autosomal dominant spinocerebellar degeneration characterized by a wide range of clinical manifestations. Unstable CAG trinucleotide repeat expansion in the MJD gene has been identified as the pathologic mutation of MJD. In this study, human SK-N-SH neuroblastoma cells stably transfected with full-length MJD with 78 CAG repeats were established. Compared with the parental cells, cells expressing mutant ataxin-3 displayed normal morphology for over 80 generations. Less than 1% of the transfected cells contained nuclear aggregates under basal conditions, indicating that this cellular model represented an early disease stage. While t-butyl hydroperoxide (TBH) was used to assess the oxidative tolerance of cells, the results demonstrated that the transfected cells were more susceptible to low concentrations of TBH than the parental cells. Most interestingly, from 2D gel electrophoresis analysis, we identified that the expression of heat shock protein 27 (HSP27), known as a suppressor of poly(Q)-mediated cell death, dramatically decreased in SK-N-SH cells stably transfected with full-length mutant MJD. The same reduction of HSP27 was further confirmed in lymphoblastoid cells from MJD patients. Our results demonstrated that both neuronal and non-neuronal cells with expanded full-length ataxin-3 revealed reduced protein expression of HSP27. We propose that the reduction of HSP27 in the early stage of the disease plays an important role during cell death process in MJD.

The hydrophobic heptad repeat in Region III of Escherichia coli transcription factor sigma 54 is essential for core RNA polymerase binding.

Escherichia coli transcription factor sigma 54 contains motifs that resemble closely those used for RNA polymerase II in mammalian cells, including two hydrophobic heptad repeats, a very acidic region and a glutamine-rich region. Triple changes in hydrophobic or multiple changes in acidic residues in Region III are known to severely impair core-binding ability. To investigate whether all the changes in triple mutants are necessary for core binding, site-directed mutagenesis was performed to create single and double mutants in the leucine or isoleucine residues in the heptad repeat in Region III. Single mutants showed no discernible loss of function. Double mutants showed partial protection of the -12 promoter element of the glnAp2 promoter due to the partial loss of their ability to bind core RNA polymerase. These mutations were deleterious to the function of sigma 54, which retained only 30-40% of wild-type mRNA levels. However, double mutants retained nearly normal ability to form open complexes. Two triple mutants created during previous work lost most, if not all, of their ability to bind core RNA polymerase, to protect the -12 promoter element of the glnAp2 promoter and to open the transcription start site. The two triple mutants produced about 20% or less than 10% of the wild-type transcripts from the glnAp2 promoter. These results demonstrate that the hydrophobic heptad repeat in Region III is essential for core RNA polymerase binding. Progressive loss of hydrophobicity of the hydrophobic heptad repeat in Region III of sigma 54 resulted in a progressive loss of core-binding ability, leading to the loss of -12 promoter element recognition and mRNA production.

Advancement of Quorum Sensing in Rhizobia / 微生物学通报

Quorum sensing is defined as the cell density-dependent regulation of gene expression, and the involved system is the quorum sensing system, in which N-acyl homoserine lactone is known as the signal molecules of most gram-negative organisms. It can regulate diverse physiological functions. This paper reviewed the quorum sensing systems and the recent advances which play a major role in the formation of the symbiosis between the rhizobia and their host plants.