64-Slice computed tomography angiography in the diagnosis and assessment of coronary artery disease: systematic review and meta-analysis

CONTEXT

Coronary artery disease (CAD) is a major cause of mortality and ill health.

OBJECTIVE

To assess whether 64-slice CT angiography might replace some coronary angiography (CA) for diagnosis and assessment of CAD.

DATA SOURCES

Electronic databases, conference proceedings and reference lists of included studies.

STUDY SELECTION

Eligible studies compared 64-slice CT with a reference standard of CA in adults with suspected/known CAD, reporting sensitivity and specificity or true and false positives and negatives.

DATA EXTRACTION

Two reviewers independently extracted data from included studies.

RESULTS

Forty studies were included; 28 provided sufficient data for inclusion in the meta-analyses, all using a cut off point of >/=50% stenosis to define significant CAD. In patient-based detection (n = 1286) 64-slice CT pooled sensitivity was 99% (95% credible interval (CrI) 97% to 99%), specificity 89% (95% CrI 83% to 94%), median positive predictive value (PPV) across studies 93% (range 64-100%) and negative predictive value (NPV) 100% (range 86-100%). In segment-based detection (n = 14 199) 64-slice CT pooled sensitivity was 90% (95% CrI 85% to 94%), specificity 97% (95% CrI 95% to 98%), median PPV across studies 76% (range 44-93%) and NPV 99% (range 95-100%).

CONCLUSIONS

64-Slice CT is highly sensitive for patient-based detection of CAD and has high NPV. An ability to rule out significant CAD means that it may have a role in the assessment of chest pain, particularly when the diagnosis remains uncertain despite clinical evaluation and simple non-invasive testing.

Systematic review of foam sclerotherapy for varicose veins

Background and method

Foam sclerotherapy is a potential treatment for varicose veins. A systematic review was undertaken to assess its safety and efficacy.

Results

Sixty-nine studies were included. The median rates of serious adverse events, including pulmonary embolism and deep vein thrombosis, were less than 1 per cent. The median rate of visual disturbance was 1·4 per cent, headache 4·2 per cent, thrombophlebitis 4·7 per cent, matting/skin staining/pigmentation 17·8 per cent and pain at the site of injection 25·6 per cent. The median rate of complete occlusion of treated veins was 87·0 per cent and for recurrence or development of new veins it was 8·1 per cent. Meta-analysis for complete occlusion suggests that foam sclerotherapy is less effective than surgery (relative risk (RR) 0·86 (95 per cent confidence interval (c.i.) 0·67 to 1·10)) but more effective than liquid sclerotherapy (RR 1·39 (95 per cent c.i. 0·91 to 2·11)), although there was substantial heterogeneity between studies.

Conclusion

Serious adverse events associated with foam sclerotherapy are rare. There is insufficient evidence to allow a meaningful comparison of the effectiveness of this treatment with that of other minimally invasive therapies or surgery.

DNA-binding determinants of the alpha subunit of RNA polymerase: novel DNA-binding domain architecture

The Escherichia coli RNA polymerase alpha-subunit binds through its carboxy-terminal domain (alpha CTD) to a recognition element, the upstream (UP) element, in certain promoters. We used genetic and biochemical techniques to identify the residues in alpha CTD important for UP-element-dependent transcription and DNA binding. These residues occur in two regions of alpha CTD, close to but distinct from, residues important for interactions with certain transcription activators. We used NMR spectroscopy to determine the secondary structure of alpha CTD, alpha CTD contains a nonstandard helix followed by four alpha-helices. The two regions of alpha CTD important for DNA binding correspond to the first alpha-helix and the loop between the third and fourth alpha-helices. The alpha CTD DNA-binding domain architecture is unlike any DNA-binding architecture identified to date, and we propose that alpha CTD has a novel mode of interaction with DNA. Our results suggest models for alpha CTD-DNA and alpha CTD-DNA-activator interactions during transcription initiation.

Systematic review and economic modelling of the relative clinical benefit and cost-effectiveness of laparoscopic surgery and robotic surgery for removal of the prostate in men with localised prostate cancer

BACKGROUND

Complete surgical removal of the prostate, radical prostatectomy, is the most frequently used treatment option for men with localised prostate cancer. The use of laparoscopic (keyhole) and robot-assisted surgery has improved operative safety but the comparative effectiveness and cost-effectiveness of these options remains uncertain.

OBJECTIVE

This study aimed to determine the relative clinical effectiveness and cost-effectiveness of robotic radical prostatectomy compared with laparoscopic radical prostatectomy in the treatment of localised prostate cancer within the UK NHS.

DATA SOURCES

MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, BIOSIS, Science Citation Index and Cochrane Central Register of Controlled Trials were searched from January 1995 until October 2010 for primary studies. Conference abstracts from meetings of the European, American and British Urological Associations were also searched. Costs were obtained from NHS sources and the manufacturer of the robotic system. Economic model parameters and distributions not obtained in the systematic review were derived from other literature sources and an advisory expert panel.

REVIEW METHODS

Evidence was considered from randomised controlled trials (RCTs) and non-randomised comparative studies of men with clinically localised prostate cancer (cT1 or cT2); outcome measures included adverse events, cancer related, functional, patient driven and descriptors of care. Two reviewers abstracted data and assessed the risk of bias of the included studies. For meta-analyses, a Bayesian indirect mixed-treatment comparison was used. Cost-effectiveness was assessed using a discrete-event simulation model.

RESULTS

The searches identified 2722 potentially relevant titles and abstracts, from which 914 reports were selected for full-text eligibility screening. Of these, data were included from 19,064 patients across one RCT and 57 non-randomised comparative studies, with very few studies considered at low risk of bias. The results of this study, although associated with some uncertainty, demonstrated that the outcomes were generally better for robotic than for laparoscopic surgery for major adverse events such as blood transfusion and organ injury rates and for rate of failure to remove the cancer (positive margin) (odds ratio 0.69; 95% credible interval 0.51 to 0.96; probability outcome favours robotic prostatectomy = 0.987). The predicted probability of a positive margin was 17.6% following robotic prostatectomy compared with 23.6% for laparoscopic prostatectomy. Restriction of the meta-analysis to studies at low risk of bias did not change the direction of effect but did decrease the precision of the effect size. There was no evidence of differences in cancer-related, patient-driven or dysfunction outcomes. The results of the economic evaluation suggested that when the difference in positive margins is equivalent to the estimates in the meta-analysis of all included studies, robotic radical prostatectomy was on average associated with an incremental cost per quality-adjusted life-year that is less than threshold values typically adopted by the NHS (£30,000) and becomes further reduced when the surgical capacity is high.

LIMITATIONS

The main limitations were the quantity and quality of the data available on cancer-related outcomes and dysfunction.

CONCLUSIONS

This study demonstrated that robotic prostatectomy had lower perioperative morbidity and a reduced risk of a positive surgical margin compared with laparoscopic prostatectomy although there was considerable uncertainty. Robotic prostatectomy will always be more costly to the NHS because of the fixed capital and maintenance charges for the robotic system. Our modelling showed that this excess cost can be reduced if capital costs of equipment are minimised and by maintaining a high case volume for each robotic system of at least 100-150 procedures per year. This finding was primarily driven by a difference in positive margin rate. There is a need for further research to establish how positive margin rates impact on long-term outcomes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The new function of circRNA: translation

Circular RNAs (circRNAs) have been considered a special class of non-coding RNAs without 5' caps and 3' tails which are covalently closed RNA molecules generated by back splicing of mRNA. For a long time, circRNAs have been considered to be directly involved in various biological processes as functional RNA. In recent years, a variety of circRNAs have been found to have translational functions, and the resultant peptides also play biological roles in the emergence and progression of human disease. The discovery of these circRNAs and their encoded peptides has enriched genomics, helped us to study the causes of diseases, and promoted the development of biotechnology. The purpose of this review is to summarize the research progress of the detection methods, translation initiation mechanism, as well as functional mechanism of peptides encoded by circRNAs, with the goal of providing the directions for the discovery of biomarkers for diagnosis, prognosis, and therapeutic targets for human disease.

Solution structures and integrin binding activities of an RGD peptide with two isomers

The Arg-Gly-Asp (RGD) sequence serves as the primary integrin recognition site in extracellular matrix proteins, and peptides containing this sequence can mimic the activities of the matrix proteins. Depending on the context of the RGD sequence, an RGD-containing peptide may bind to all of the RGD-directed integrins, to a few, or to only a single one. We have previously isolated from a phage-displayed peptide library a cyclic peptide that binds avidly to the alpha(v)beta3 and alpha(v)beta5 integrins but does not bind to other closely related integrins. This peptide, ACDCRGDCFCG, exists in two natural configurations depending on internal disulfide bonding. The peptide with the 1-4; 2-3 disulfide bond arrangement accounts for most of the alpha(v) integrin binding activity, whereas the 1-3; 2-4 peptide is about 10-fold less potent. Solution structure analysis by nuclear magnetic resonance reveals an entirely different presentation of the RGD motif in the two isomers of RGD-4C. These results provide new insight into the ligand recognition specificity of integrins.

Diet and brain cancer in adults: a case-control study in northeast China

A hospital-based case-control study was conducted in the Heilongjiang Province of northeast China between May 1993 and May 1995. A total of 129 histologically confirmed brain cancer cases (73 gliomas and 56 meningiomas) and 258 matched controls were interviewed in 6 major hospitals to examine the influence of dietary factors in developing brain cancer. Information was obtained about frequency of consumption of 57 food items. Odds ratios (ORs) were obtained from conditional logistic regression, including allowance for socio-demographic factors, alcohol, tobacco and total energy intake. Consumption of fresh vegetables (OR = 0.29 for the highest quartile compared with the lowest one), and specifically of Chinese cabbage and onion, fruit (OR = 0.15), fresh fish (OR = 0.38) and poultry (OR = 0.16) was inversely related to the risk of developing brain cancer. A protective effect was also seen for vitamin E intake, calcium and, although non-significantly, beta-carotene and vitamin C. Risk of brain cancer increased with consumption of salted vegetables (OR = 2.54) and salted fish.

The solution structures of the trp repressor-operator DNA complex

The solution structures of the complex between Escherichia coli trp holorepressor and a 20 base-pair consensus operator DNA were determined. The majority of proton chemical shifts of the trp holorepressor and operator DNA were assigned from homonuclear 2D NOESY spectra of selectively deuterated analog-operator DNA complexes and the 3D NOESY-HMQC spectrum of a uniformly 15N-labeled repressor-operator DNA complex. The structures were calculated using restrained molecular dynamics and sequential simulated annealing with 4086 NOE and other experimental constraints. The root-mean-squared deviation (RMSD) among the calculated structures and their mean is 0.9(+/- 0.3)A for the repressor backbone, 1.1(+/- 0.5)A for the DNA backbone, and 1.3(+/- 0.3)A for all heavy atoms. The DNA is deformed to a significant extent from the standard B DNA structure to fit the helix-turn-helix (HTH) segment of the repressor (helices D and E) into its major grooves. Little change is found in the ABCF core of the repressor on complexation in comparison to the free repressor, but changes in the cofactor L-tryptophan binding pocket and the HTH segment are observed. The N-terminal residues (2 to 17) are found to be disordered and do not form stable interactions with DNA. Direct H-bonding to the bases of the operator DNA is consistent with all of our observed NOE constraints. Hydrogen bonds from NH eta 1 and NH eta 2 of Arg69 to O-6 and N-7 of G2 are compatible with the solution structure, as they are with the crystal structure. Other direct H-bonds from Lys72, Ala80, Ile79, Thr83 and Arg84 to base-pair functional groups can also be formed in our solution structures.

Berberine Ameliorates Periodontal Bone Loss by Regulating Gut Microbiota

Postmenopausal osteoporosis (PMO) is a risk factor for periodontitis, and current therapeutics against PMO prevent the aggravated alveolar bone loss of periodontitis in estrogen-deficient women. Gut microbiota is recognized as a promising therapeutic target for PMO. Berberine extracted from Chinese medicinal plants has shown its effectiveness in the treatment of metabolic diseases such as obesity and diabetes via regulating gut microbiota. Here, we hypothesize that berberine ameliorates periodontal bone loss by improving the intestinal barriers by regulating gut microbiota under an estrogen-deficient condition. Experimental periodontitis was established in ovariectomized (OVX) rats, and the OVX-periodontitis rats were treated with berberine for 7 wk before sacrifice for analyses. Micro–computed tomography and histologic analyses showed that berberine treatment significantly reduced alveolar bone loss and improved bone metabolism of OVX-periodontitis rats as compared with the vehicle-treated OVX-periodontitis rats. In parallel, berberine-treated OVX-periodontitis rats harbored a higher abundance of butyrate-producing gut microbiota with elevated butyrate generation, as demonstrated by 16S rRNA sequencing and high-performance liquid chromatography analysis. Berberine-treated OVX-periodontitis rats consistently showed improved intestinal barrier integrity and decreased intestinal paracellular permeability with a lower level of serum endotoxin. In parallel, IL-17A-related immune responses were attenuated in berberine-treated OVX-periodontitis rats with a lower serum level of proinflammatory cytokines and reduced IL-17A+ cells in alveolar bone as compared with vehicle-treated OVX-periodontitis rats. Our data indicate that gut microbiota is a potential target for the treatment of estrogen deficiency–aggravated periodontal bone loss, and berberine represents a promising adjuvant therapeutic by modulating gut microbiota.

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats

The subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.

Refined solution structures of the Escherichia coli trp holo- and aporepressor

The solution structures of the trp-repressor from Escherichia coli in both the liganded (holo-) and unliganded (apo-) form, have been refined by restrained molecular dynamics with simulated annealing using the program XPLOR and additional experimental constraints. The ensemble of refined holorepressor structures have a root-mean-square deviation (r.m.s.d.) of 0.8 A relative to the average structure for the backbone of the dimer core (helices A, B, C, A', B', C') and 2.5 A for the helix-turn-helix DNA-binding domain (helices D and E). The corresponding values for the aporepressor are 0.9 A for the backbone of the ABC-dimer core and 3.2 A for the DE helix-turn-helix. The r.m.s.d. of the average structures from the corresponding crystal structures are 2.3 A for the holorepressor ABC core and 4.2 A for its DE region; 2.3 A for the aporepressor core and 5.5 A for its DE region. The relative disorder of the DNA-binding domain is reflected in a number of experimental parameters including substantially more rapid backbone proton exchange rates, exchange-limited relaxation times and crystallographic B-factors. The stabilizing effect of the L-Trp ligand is evident in these measurements, as it is in the higher precision of the holorepressor structure.

Long non-coding RNA MEG3 suppresses migration and invasion of thyroid carcinoma by targeting of Rac1

Thyroid cancer, the most common primary endocrine malignancy in adult, imperatively requires new therapeutic studies that could target the molecular regulatory mechanism. Even though emerging evidence showed that long noncoding RNAs (Lnc-RNAs) are involved in different biological characteristic of malignant tumor, such as cell growth and apoptosis as well as cancer progression and metastasis. Limited data are available on the function of Lnc-RNAs in thyroid cancer invasion and metastasis. Among the 5 tested lnc-RNAs , the present study demonstrates that MEG3 was significantly down-regulated in papillary thyroid carcinoma (PTC) tissues with lymph-node metastasis than in primary thyroid cancer. Moreover, the down- regulated MEG3 was associated with lymph-node metastasis. Over-expression of MEG3 could strongly inhibit the cell migration and invasion in TPC-1 and HTH83 thyroid cancer cell lines. In addition, we also showed that Rac1 was negatively regulated by lncRNA-MEG3 at the posttranscriptional level, via a specific target site within the 3΄UTR by dual luciferase reporter assay. The expression of Rac1 was inversely correlated with lncRNA-MEG3 expression in PTC tissues. Thus, this study suggests that MEG3 acts as novel suppressor of migration and invasion by targeting Rac1 gene.

Phase II study of the farnesyl transferase inhibitor R115777 in patients with sensitive relapse small-cell lung cancer

BACKGROUND

R115777 (tipifarnib, Zarnestra) is a farnesyl transferase inhibitor that blocks the farnesylation of proteins involved in signal transduction pathways critical for cell proliferation and survival. This multicenter phase II study was conducted to determine the efficacy, tolerability and pharmacokinetics of R115777 in patients with relapsed small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Patients who had a partial or complete response to their initial chemotherapy regimen, followed by at least 3 months off treatment before relapse (sensitive relapse) were eligible. R115777 was administered in 3-week cycles at a dose of 400 mg orally twice daily for 14 consecutive days followed by 7 days off treatment.

RESULTS

Twenty-two patients were enrolled. The median progression-free survival was 1.4 months and median overall survival was 6.8 months. Non-hematological toxicities were predominantly grade 1-2 and included nausea (64%) and fatigue (60%). Grade 3-4 granulocytopenia and thrombocytopenia occurred in 27% and 23% of patients, respectively. Febrile neutropenia was not observed. Pharmacokinetic studies demonstrated peak plasma concentrations of R115777 2.6-4.5 h after oral dosing and no significant drug accumulation. The trial was terminated because no objective responses were observed in 20 patients evaluable for response.

CONCLUSIONS

R115777 showed no significant antitumor activity as a single agent in sensitive-relapse SCLC.

MicroRNA-25 functions in regulation of pigmentation by targeting the transcription factor MITF in Alpaca (Lama pacos) skin melanocytes

Although the influence of endocrine factors is well established, the molecular and cellular mechanisms controlling coat color are not completely understood. A major mechanism for post-transcriptional regulation of gene expression is through the action of microRNAs (miRNAs), which anneal to the 3' untranslated region of mRNAs in a sequence-specific fashion and either block translation or promote transcript degradation. In this study, we investigated the expression of miRNAs in the skin of alpacas with brown vs white coat color using a microarray screen; identified potential mRNA targets for identified miRNAs among coat color genes; and subsequently determined the ability of a specific, differentially expressed miRNA (miR-25) to suppress expression of micropthalmia-associated transcription factor (MITF), a predicted miR-25 target gene that regulates genes linked to coat color. Expression of 10 different miRNA species in the skin of alpacas with brown vs white coat color was identified from microarray screens. Of the 10 alpaca skin miRNAs identified, predicted binding sites in the 3' untranslated region of RNAs encoding for known genes linked to coat color were primarily for miR-25, but sites were also identified for miR-129 and miR-377. Potential miR-25 binding sites were present in transcripts encoding for 11 coat color genes, including MITF. An inverse relationship between transcript abundance for MITF and miR-25 was observed in skin samples collected from alpacas with white vs brown coat color. Furthermore, overexpression of miR-25 in cultured melanocytes reduced MITF mRNA and protein abundance and corresponding mRNA abundance for the MITF-regulated enzymes tyrosinase and tyrosinase-related protein 1. Results support a novel functional role for miRNA-25 in the regulation of gene expression linked to coat color.

Identification of determinants for inhibitor binding within the RNA active site of human telomerase using PNA scanning

Telomerase is a ribonucleoprotein that participates in the maintenance of telomere length. Its activity is up-regulated in many tumor types, suggesting that it may be a novel target for chemotherapy. The RNA component of telomerase contains an active site that plays at least two roles&sbd;binding telomere ends and templating their replication [Greider, C. W., & Blackburn, E. H. (1989) Nature 337, 331-337]. The accessibility of RNA nucleotides for inhibitor binding cannot be assumed because of the potential for RNA secondary structure and RNA-protein interactions. Here we use high-affinity recognition by overlapping peptide nucleic acids (PNAs) [Nielsen, P. E., et al. (1991) Science 254, 1497-1500] to identify nucleotides within the RNA active site of telomerase that are determinants for inhibitor recognition. The IC50 for inhibition decreases from 30 microM to 10 nM as cytidines 50-52 (C50-52) at the boundary between the alignment and elongation domains are recognized by PNAs overlapping from the 5' direction. As C50-52 are uncovered in the 3' direction, IC50 increases from 10 nM to 300 nM. As cytidine 56 at the extreme 3' end of the active site is uncovered, IC50 values increase from 0.5 microM to 10 microM. This analysis demonstrates that C50-C52 and C56 are important for PNA recognition and are physically accessible for inhibitor binding. We use identification of these key determinants to minimize the size of PNA inhibitors, and knowledge of these determinants should facilitate design of other small molecules capable of targeting telomerase. The striking differences in IC50 values for inhibition of telomerase activity by related PNAs emphasize the potential of PNAs to be sensitive probes for mapping complex nucleic acids. We also find that PNA hybridization is sensitive to nearest-neighbor interactions, and that consecutive guanine bases within a PNA strand increase binding to complementary DNA and RNA sequences.

Down-regulated long non-coding RNA H19 inhibits carcinogenesis of renal cell carcinoma

Long non-coding RNAs (lncRNAs) have been shown to have important regulatory roles in cancer biology. LncRNA H19 has been recently shown to be upregulated and play important roles in several cancers such as breast cancer, bladder cancer, and gastric cancer. However, the role of H19 in clear cell renal carcinoma (ccRCC) remains largely unknown.The expression levels of lncRNA H19 in ccRCC tissues and renal cancer cell lines were evaluated by quantitative Real-time PCR (qRT-PCR). And its association with overall survival of patients was analyzed by statistical analysis. Small interfering RNA (siRNA) was used to suppress H19 expression in renal cancer cell lines. In vitro assays were performed to further explore its role in tumor progression.The relative level of H19 was significantly higher in ccRCC compared to the adjacent normal renal tissues. And higher expression of H19 was found in renal cancer cells compared to the nonmalignant renal cells HK-2. Furthermore, The ccRCC patients with higher H19 expression had more advanced clinical stage and poorer prognosis than those with lower expression, Kaplan-Meier analysis revealed that patients with higher H19 expression had a poorer overall survival and H19 expression could be an independent prognostic marker for ccRCC patient. The results of in vitro assays indicated that knockdown of H19 reduced cell proliferation, invasion, and migration. Our data suggested that lncRNA H19 might be considered as a potential prognostic indicator and a target for gene therapy of ccRCC.