[Analysis of the effect of percutaneous vertebroplasty combined with (125)I seed implantation in the treatment of spinal metastatic epidural spinal cord compression].

Objective: To investigate the clinical efficacy of percutaneous vertebroplasty (PVP) combined with iodine-125 ((125)I) seed brachytherapy in the treatment of spinal metastatic epidural spinal cord compression (MESCC) and toassess the changes inthe grade of epidural spinal cord compression (ESCC) by magnetic resonance imaging (MRI). Methods: A total of 37 MESCC patients treated with PVP combined with (125)I seed brachytherapy in the interventional and vascular surgery department of Zhongda Hospital affiliated to Southeast University from January 2014 to June 2019 were retrospectively analyzed, including 23 cases of bilateral lower limbs paralysis. Total diseased vertebrae are 39 segments. Visual analogue scale (VAS) and paralysis of lower extremities were evaluated regularly before and after treatment, and VAS values at different follow-up time points were compared. At the same time, MRI was used to evaluate the changes of ESCC grade in the spinal canal and calculate the local lesion efficiency after operation. The postoperative local lesion efficiency at different follow-up times was compared. Results: PVP combined with (125)I seed implantation in all diseased vertebral bodies was successful. The average injection volume of polymethylmethacrylate (PMMA) was (3.2±1.3) ml/segment, the average number of (125)I seed implanted was (25.0±8.6) seeds/segment and the average radiation dose was (15.0±5.1) mCi/segment. The VAS before operation was 8.5, and postoperative VAS were respectively 3.6±1.3, 3.8±1.5, 3.4±1.4, 5.5±1.0, 5.9±1.4 at 5 days, 1 month, 3 months, 6 months, and 1 year after operation. The differences between all follow-up time points and preoperative VAS values were statistically significant (all P<0.001). Compared with 5 days, 1 month and 3 months after operation, VAS increased significantly at 6 months and 1 year after operation, and the difference was statistically significant (all P<0.001); there was no significant difference between the VAS value at 6 months after operation and 1 year after operation (P=0.405). At a follow-up of 3 months, 22 of 23 patients with paralysis of bilateral lower limbs regained the functions of autonomous walking and voiding; the effective rates of MESCC local lesions evaluated by MRI at 1 month, 3 months, 6 months, and>1 year were 89.7%, 91.9%, 90.6%, and 94.7%, respectively, and there was no statistically significant differences among those follow-up time points (all P>0.05). Conclusions: PVP combined with (125)I seed brachytherapy in the treatment of MESCC has significant improvement in immediate pain relief and spinal cord function. After combined treatment, MRI showed that the tumors around the spinal cord regressed dramatically, which could considerably reduce the MESCC grade and remain stable for a long time.

[Impact of symptom onset to first medical contact time on the prognosis of patients with acute ST-segment elevation myocardial infarction].

Objective: To investigate the impact of symptom onset to first medical contact (SO-to-FMC)time on the prognosis of patients with acute ST-segment elevation myocardial infarction(STEMI). Methods: The clinical data of 341 consecutive STEMI patients, who were hospitalized to our hospital and received primary percutaneous coronary intervention(PCI) from August 2011 to April 2016, were retrospectively analyzed. The patients were divided into ≤90 min group (201 cases) and >90 min group (140 cases) according to the SO-to-FMC time. The treatment time, mortality and incidence of major adverse cardiac and cerebro-vascular events(MACCE) were analyzed. The risk factor of 1-year mortality after PCI and 1-year incidence of MACCE during the post-discharge follow-up period were analyzed by binary logistic regression analysis. The predictor of 4.5-year mortality after PCI was analyzed by multivariate Cox regression analysis. Methods The door to balloon time (104(88, 125) min vs. 111(92, 144)min, P=0.023), first medical contact to balloon time(146(119, 197) min vs. 177(125, 237)min, P=0.005), and symptom onset-to-balloon time(200(170, 257) min vs. 338(270, 474)min, P<0.001)were all significantly shorter in the ≤90 min group than in>90 min group. The 30-day mortality (2.99% (6/201) vs. 7.86%(11/140), P=0.042), 1-year mortality (2.89 (5/173) vs. 9.57(11/115), P=0.015), 1-year incidence of MACCE during the post-discharge follow-up period(1.16%(2/173) vs. 6.96%(8/115), P=0.021), and 4.5-year cumulative mortality(3.00% vs. 11.20%, P=0.007) after PCI were significantly lower in the ≤90 min group than in the >90 min group. Moreover, the 4.5-year incidence with free of MACCE (97.20% vs. 88.80%, P=0.025) during the post-discharge follow-up period was significantly higher in the ≤90 min group than in the >90 min group. In-hospital mortality was similar between the two groups (2.49%(5/201) vs. 6.43%(9/140), P=0.071). Results: The door to balloon time (104(88, 125) min vs. 111(92, 144)min, P=0.023) , first medical contact to balloon time(146(119, 197) min vs. 177(125, 237)min, P=0.005), and symptom onset-to-balloon time(200(170, 257) min vs. 338(270, 474)min, P<0.001) were all significantly shorter in the ≤90 min group than in >90 min group. The 30-day mortality(2.99% (6/201) vs. 7.86%(11/140), P=0.042), 1-year mortality (2.89(5/173) vs. 9.57(11/115), P=0.015), 1-year incidence of MACCE during the post-discharge follow-up period (1.16%(2/173) vs. 6.96%(8/115), P=0.021), and 4.5-year cumulative mortality (3.00% vs. 11.20%, P=0.007) after PCI were significantly lower in the ≤90 min group than in the >90 min group. Moreover, the 4.5-year incidence with free of MACCE (97.20% vs. 88.80%, P=0.025) during the post-discharge follow-up period was significantly higher in the ≤90 min group than in the >90 min group. In-hospital mortality was similar between the two groups (2.49%(5/201) vs. 6.43%(9/140), P=0.071). Results of binary logistic regression analysis showed that the SO-to-FMC time >90 min was the risk factor of 1-year mortality(OR=2.90, 95%CI 1.22-6.92, P=0.016) and 1-year incidence of MACCE (OR=5.19, 95%CI 1.21-22.20, P=0.026) during the post-discharge follow-up period. Multivariate Cox regression analysis demonstrated that the SO-to-FMC time >90 min was the risk factor of 4.5-year mortality after PCI in patients with STEMI (HR=2.88, 95%CI 1.10-7.53, P=0.031). Conclusion: Shorting the SO-to-FMC time can significantly reduce the treatment time of STEMI patients, short and long-term mortalities and the incidence of MACCE, and improve the prognosis of patients with STEMI.

Anabaena sp. strain PCC 7120 ntcA gene required for growth on nitrate and heterocyst development.

The Anabaena sp. strain PCC 7120 ntcA (bifA) gene encodes a sequence-specific DNA-binding protein, NtcA (BifA, VF1) that interacts with the upstream region of several genes, including glnA, xisA, rbcL, and nifH. We have constructed a ntcA null mutant by interrupting the gene with an omega Spr-Smr cassette. The ntcA mutant was not able to grow with nitrate or atmospheric dinitrogen as the sole nitrogen source but could be grown on medium containing ammonium. The ntcA mutant was unable to form heterocysts and did not rearrange the nifD or fdxN elements after induction on a medium lacking combined nitrogen. Northern (RNA) analysis of ntcA in the wild-type strain during nitrogen stepdown showed a peak of ntcA message at an early stage (12 h) of heterocyst induction. Complementation of the ntcA mutant with a DNA fragment containing the ntcA gene and 251 bp of upstream sequence on a shuttle vector restored a wild-type phenotype; however, a similar construction containing 87 bp of upstream sequence only partially restored the phenotype. Northern analysis of RNA samples isolated from ammonium-grown cultures of the ntcA mutant showed reduced amounts of glnA message and the absence of a 1.7-kb transcript. In the wild type, the 1.7-kb transcript represents the majority of glnA transcripts after nitrogen stepdown. The ntcA mutant showed a normal pattern of rbcLS messages under these growth conditions.

Two Anabaena sp. strain PCC 7120 DNA-binding factors interact with vegetative cell- and heterocyst-specific genes.

The DNA-binding factor BifA (previously called VF1) binds upstream of the developmentally regulated site-specific recombinase gene xisA in the cyanobacterium Anabaena sp. strain PCC 7120. Besides binding xisA, BifA also binds the glnA, rbcL, and nifH promoter regions. DNase I footprint analysis of BifA binding to glnA showed a protected region -125 to -148 bp upstream of the translation start site. The binding site is between the major glnA transcription start site used in vegetative cells (RNAII) and the major transcription start site used under nitrogen-deficient conditions (RNAI). The two BifA-binding sites on the rbcL promoter were localized to a 24-bp region from +12 to -12 nucleotides and to a 12-bp region from -43 to -54 nucleotides with respect to the transcription start site. Comparison of the BifA binding sites on the glnA, xisA, and rbcL upstream regions revealed the consensus recognition sequence TGT(N9 or 10) ACA. We have identified a second DNA-binding activity (factor 2) that interacts with rbcL and xisA upstream regions. Factor 2 can be resolved from BifA by heparin-Sepharose chromatography and was present in a bifA mutant. Analysis of partially purified vegetative cell and heterocyst extracts showed that whereas BifA was present in both cell types, factor 2 was present only in vegetative cells. DNase I footprint analysis of factor 2 binding to rbcL showed protection of a 63-bp region between positions -15 and -77 with respect to the transcription start site. The factor 2 binding site on xisA was localized to a 68-bp region that showed considerable overlap with the BifA binding sites.

Cooperative binding of polyamines induces the Escherichia coli single-strand binding protein-DNA binding mode transitions.

The Escherichia coli single-strand binding (SSB) protein is an essential protein involved in DNA replication, recombination, and repair processes. The tetrameric protein binds to ss nucleic acids in a number of different binding modes in vitro. These modes differ in the number of nucleotides occluded per SSB tetramer and in the type and degree of cooperative complexes that are formed with ss DNA. Although it is not yet known whether only one or all of these modes function in vivo, based on the dramatically different properties of the SSB tetramer in these different ss DNA binding modes, it has been suggested that the different modes may function selectively in replication, recombination, and/or repair. The transitions between these different modes are very sensitive to solution conditions, including salt (concentration, as well as cation and anion type), pH, and temperature. We have examined the effects of multivalent cations, principally the polyamine spermine, on the SSB-ss poly(dT) binding mode transitions and find that the transition from the (SSB)35 to the (SSB)56 binding mode can be induced by micromolar concentrations of polyamines as well as the inorganic cation Co(NH3)6(3+). Furthermore, these multivalent cations, as well as Mg2+, induce the binding mode transition by binding cooperatively to the SSB-poly(dT) complexes. These observations are interesting in light of the fact that polyamines, such as spermidine, are part of the ionic environment in E. coli and hence these cations are likely to affect the distribution of SSB-ss DNA binding modes in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Anabaena sp. strain PCC 7120 bifA gene encoding a sequence-specific DNA-binding protein cloned by in vivo transcriptional interference selection.

VF1 is a DNA-binding protein from the cyanobacterium Anabaena sp. strain PCC 7120. VF1 was originally identified on the basis of its binding affinity to the upstream region of xisA, which encodes a heterocyst-specific site-specific recombinase. VF1 also binds to the glnA, rbcL, and nifH promoters in vitro, suggesting that VF1 interacts with genes expressed in both vegetative cells and heterocysts. The role of VF1 in regulating gene expression in PCC 7120 is unknown. As a step towards the goal of understanding the role of VF1 in regulating gene expression, we have cloned the bifA gene by using a genetic selection strategy. bifA encodes a protein, BifA, that has chromatographic and DNA-binding properties indistinguishable from those of VF1. The cloning strategy was based on a transcriptional interference assay in which a strong synthetic promoter, conII, interferes with the expression of an aadA gene, which provides resistance to spectinomycin and streptomycin (S. J. Elledge, P. Sugiono, L. Guarente, and R. W. Davis, Proc. Natl. Acad. Sci. USA 86:3689-3693, 1989). A selection plasmid, pAM994, which has the conII promoter negatively regulated by a VF1-binding site, was used to enrich for VF1-producing clones from an expression library containing PCC 7120 DNA fragments. Mobility shift assays were used to identify a 672-bp open reading frame that encoded VF1-like binding activity. The deduced BifA amino acid sequence shows 77% identity to NtcA, which is a global regulator involved in nitrogen control in Synechococcus sp. strain PCC 7942. Both BifA and NtcA belong to the cyclic AMP receptor protein (CRP) family of prokaryotic regulatory proteins. Genes similar to envM, hisB, and ORF60-5 were found near the bifA gene.

Transcription of the Anabaena sp. strain PCC 7120 ntcA gene: multiple transcripts and NtcA binding.

The Anabaena sp. strain PCC 7120 ntcA gene showed multiple transcripts with different 5' ends. The relative abundance of transcripts varied in response to nitrogen availability. The ntcA product, NtcA, showed binding to the promoter region of its own gene. The binding site mapped to a region between the transcription start site used under nitrogen-replete conditions and the start sites used under nitrogen-limiting conditions, suggesting that NtcA regulates its own expression.

Cloning and characterization of a novel Kruppel-associated box family transcriptional repressor that interacts with the retinoblastoma gene product, RB.

The retinoblastoma gene product, RB, seems to function as a key tumor suppressor by repressing the expression of genes activated by members of the E2F family of transcription factors. In order to accomplish this, RB has been proposed to interact with a transcriptional repressor. However, no genuine transcriptional repressors have been identified by virtue of interaction with RB. By using the yeast two-hybrid system, we have identified a novel member of a known family of transcriptional repressors that contain zinc fingers of the Kruppel type and a portable transcriptional repressor motif known as the Kruppel-associated box (KRAB). The mouse and human forms of the novel RB-associated KRAB protein (RBaK) are widely expressed. The amino acid motif that links the KRAB domain and zinc fingers appears to be required for interaction with RB in vitro. Human RBaK ectopically expressed in fibroblasts is an 80-kDa protein that is localized to the nucleus. The expression of either RB or RBaK in 10T1/2 fibroblasts represses the activation of an E2F-dependent promoter and decreases DNA synthesis to a similar degree. However, a mutant form of RBaK that cannot interact with RB in vitro is unable to prevent DNA synthesis. We present a model in which RB physically interacts with the novel transcriptional repressor RBaK to repress E2F-dependent genes and prevent DNA synthesis.

A sequence-specific DNA-binding factor (VF1) from Anabaena sp. strain PCC 7120 vegetative cells binds to three adjacent sites in the xisA upstream region.

A DNA-binding factor (VF1) partially purified from Anabaena sp. strain PCC 7120 vegetative cell extracts by heparin-Sepharose chromatography was found to have affinity for the xisA upstream region. The xisA gene is required for excision of an 11-kilobase element from the nifD gene during heterocyst differentiation. Previous studies of the xisA upstream sequences demonstrated that deletion of this region is required for the expression of xisA from heterologous promoters in vegetative cells. Mobility shift assays with a labeled 250-base-pair fragment containing the binding sites revealed three distinct DNA-protein complexes. Competition experiments showed that VF1 also bound to the upstream sequences of the rbcL and glnA genes, but the rbcL and glnA fragments showed only single complexes in mobility shift assays. The upstream region of the nifH gene formed a weak complex with VF1. DNase footprinting and deletion analysis of the xisA binding site mapped the binding to a 66-base-pair region containing three repeats of the consensus recognition sequence ACATT.