血管闭合器应用的现况与展望

股动脉径路是冠状动脉及外周血管介入诊疗的主要途径。然而,股动脉径路穿刺的围术期血管并发症仍是每个介入医生时常面对的问题。研究显示,与压迫止血比较,血管闭合器可减少围术期血管并发症,缩短患者制动时间,增加患者舒适度。现就相关内容及最新进展进行简要综述。     

Teaching knee joint aspiration to medical students—an effective training with long-term benefits

The objective of this study was to assess the effectiveness of undergraduate training in knee aspiration and to determine the impact this had on subsequent postgraduate clinical practice. This paper is a cohort study of undergraduate training with a cross-sectional questionnaire study of postgraduate practice. The study was held at the University of Cambridge and NHS hospitals in the Eastern Region Postgraduate Deanery (England). The main outcome measures are the undergraduate competence in practical skills in a simulated setting and the differences in postgraduate practice with or without prior undergraduate training in knee aspiration. Implementing an undergraduate training programme in knee aspiration resulted in student competence in this skill. Undergraduate teaching of knee aspiration also improved postgraduate clinical practice, significantly increasing trainee doctor confidence and also increasing the frequency with which knee aspiration was undertaken. Postgraduate reinforcement of learning was identified as an additional requirement. Undergraduate teaching of knee aspiration not only results in competent performance in end of course assessments but also improves postgraduate confidence that potentially translates into improved clinical practice.     

Delay discounting, impulsiveness, and addiction severity in opioid-dependent patients

Individuals who abuse drugs show higher delay discounting (DD) rate and impulsiveness scores compared with controls; however, it is unclear if DD rate covaries with severity of the addiction or if an individual's discounting rate can be changed by effective substance abuse treatment. This study compared methadone maintenance treatment (MMT) patients (n = 30) who had not used illegal drugs for 2 years with drug-using MMT patients (n = 30) and controls (n = 25) in terms of addiction severity, DD rate, and impulsiveness. Methadone patients abstinent from illegal drugs scored significantly lower on a number of addiction severity measures than the drug-using methadone patients. In addition, both groups of MMT patients showed significantly higher rates of DD and impulsiveness than the control group; however, no differences in DD rate or impulsiveness were found between the groups of patients. Results suggest that DD rate and impulsiveness may not covary with indicators of addiction severity in MMT patients.     

Investigation of Cortical Glutamate–Glutamine and γ-Aminobutyric Acid in Obsessive–Compulsive Disorder by Proton Magnetic Resonance Spectroscopy

Glutamatergic abnormalities in corticostriatal brain circuits are thought to underlie obsessive–compulsive disorder (OCD). Whether these abnormalities exist in adults with OCD is not clear. We used proton magnetic resonance spectroscopy (¹H MRS) to test our hypothesis that unmedicated adults with OCD have reduced glutamate plus glutamine (Glx) levels in the medial prefrontal cortex (MPFC) compared with healthy controls. Levels of γ-aminobutyric acid (GABA) were also explored. Twenty-four unmedicated adults with OCD and 22 matched healthy control subjects underwent ¹H MRS scans at 3.0 T. Resonances of both Glx and GABA were obtained using the standard J-editing technique and assessed as ratios relative to voxel tissue water (W) in the MPFC (the region of interest) and the dorsolateral prefrontal cortex (DLPFC) to explore the regional specificity of any finding. In the MPFC, Glx/W did not differ by diagnostic group (p=0.98) or sex (p=0.57). However, GABA/W was decreased in OCD (2.16±0.46 × 10⁻³) compared with healthy controls (2.43±0.45 × 10⁻³, p=0.045); moreover, age of OCD onset was inversely correlated with MPFC GABA/W (r=−0.50, p=0.015). MPFC GABA/W was higher in females than in males. In the DLPFC, there were no main effects of diagnosis or gender on Glx/W or GABA/W. These data indicate that unmedicated adults with OCD do not have Glx abnormalities in a MPFC voxel that includes the pregenual anterior cingulate cortex. However, they may have decreased MPFC GABA levels. How GABA abnormalities might contribute to corticostriatal dysfunction in OCD deserves further study.     

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench.     

Coelomic fluid: a complimentary biological medium to assess sub-lethal endosulfan exposure using ¹H NMR-based earthworm metabolomics

Endosulfan is an environmentally persistent pesticide and has been shown to be genotoxic, neurotoxic and carcinogenic to surrounding organisms. Earthworms are widely used in environmental metabolomic studies to assess soil ecotoxicity. Previous nuclear magnetic resonance (NMR)-based metabolomic studies have analyzed earthworm tissue extracts after exposure to endosulfan and identified some key metabolic indicators that can be used as biomarkers of stress. However, some metabolites may have been masked due to overlap with other metabolites in the tissue extract. Therefore, in this study, the coelomic fluid (CF) and the tissue extract of the earthworm, Eisenia fetida, were both investigated using 1H NMR-based metabolomics to analyze their metabolic profile in response to endosulfan exposure at three sub-lethal (below LC??) concentrations. Principal component analysis determined the earthworm CF and earthworm tissue extract to both have significant separation between the exposed and control at the two highest sub-lethal endosulfan exposures (1.0 and 2.0 μg cm?2). Alanine, glycine, malate, α-ketoglutarate, succinate, betaine, myo-inositol, lactate and spermidine in the earthworm CF and alanine, glutamine, fumarate, glutamate, maltose, melibiose, ATP and lactate in earthworm tissue extract were all detected as having significant fluctuations after endosulfan exposure. An increase in ATP production was detected by the increase activity in the citric acid cycle and by anaerobic metabolism. A significant decrease in the polyamine, spermidine after endosulfan exposure describes an apoptotic mode of protection which correlates to a previous endosulfan exposure study where DNA damage has been reported. This study highlights that earthworm CF is a complementary biological medium to tissue extracts and can be helpful to better understand the toxic mode of action of contaminants at sub-lethal levels in the environment.     

Patterning and detailed study of human hNT astrocytes on parylene-C/silicon dioxide substrates to the single cell level

It is estimated that the adult human brain contains 100 billion neurons with 5-10 times as many astrocytes. Although it has been generally considered that the astrocyte is a simple supportive cell to the neuron, recent research has revealed new functionality of the astrocyte in the form of information transfer to neurons of the brain. In our previous work we developed a protocol to pattern the hNT neuron (derived from the human teratocarcinoma cell line (hNT)) on parylene-C/SiO(2) substrates. In this work, we report how we have managed to pattern hNT astrocytes, on parylene-C/SiO(2) substrates to single cell resolution. This article disseminates the nanofabrication and cell culturing steps necessary for the patterning of such cells. In addition, it reports the necessary strip lengths and strip width dimensions of parylene-C that encourage high degrees of cellular coverage and single cell isolation for this cell type. The significance in patterning the hNT astrocyte on silicon chip is that it will help enable single cell and network studies into the undiscovered functionality of this interesting cell, thus, contributing to closer pathological studies of the human brain.     

Staggered overdose pattern and delay to hospital presentation are associated with adverse outcomes following paracetamol-induced hepatotoxicity

AIMS

Paracetamol (acetaminophen) poisoning remains the major cause of severe acute hepatotoxicity in the UK. In this large single centre cohort study we examined the clinical impact of staggered overdoses and delayed presentation following paracetamol overdose.

RESULTS

Between 1992 and 2008, 663 patients were admitted with paracetamol-induced severe liver injury, of whom 161 (24.3%) had taken a staggered overdose. Staggered overdose patients were significantly older and more likely to abuse alcohol than single time point overdose patients. Relief of pain (58.2%) was the commonest rationale for repeated supratherapeutic ingestion. Despite lower total ingested paracetamol doses and lower admission serum alanine aminotransferase concentrations, staggered overdose patients were more likely to be encephalopathic on admission, require renal replacement therapy or mechanical ventilation and had higher mortality rates compared with single time point overdoses (37.3% vs. 27.8%, P = 0.025), although this overdose pattern did not independently predict death. The King''s College poor prognostic criteria had reduced sensitivity (77.6, 95% CI 70.8, 81.5) for this pattern of overdose. Of the 396/450 (88.0%) single time point overdoses in whom accurate timings could be obtained, 178 (44.9%) presented to medical services >24 h following overdose. Delayed presentation beyond 24 h post overdose was independently associated with death/liver transplantation (OR 2.25, 95% CI 1.23, 4.12, P = 0.009).

CONCLUSIONS

Both delayed presentation and staggered overdose pattern are associated with adverse outcomes following paracetamol overdose. These patients are at increased risk of developing multi-organ failure and should be considered for early transfer to specialist liver centres.