AV Nodal Reentrant Tachycardia Causing Inappropriate ICD Shocks In A Patient With Arrhythmogenic RV Dysplasia

We report a patient with an implantable cardioverter defibrillator (ICD) for arrhythmogenic right ventricular dysplasia (ARVD) who received inappropriate shocks for atrioventricular node reentry tachycardia (AVRNT). Patient had multiple shocks for tachycardia with EGM characteristics of very short VA interval and CL of 300 msec. An electrophysiologic (EP) study reproducibly induced typical AVNRT with similar features. The slow AV nodal pathway ablation resolved the ICD shocks. Despite increasingly sophisticated discrimination algorithms available in modern ICDs, the ability to differentiate SVT from VT can be challenging. Our patient received inappropriate shocks for AVNRT. When device interrogation alone is not conclusive, an EP study may be necessary to determine the appropriate therapeutic course.     

Narrating Kidney Disease: The Significance Of Sensation And Time In The Emplotment Of Patient Experience

Drawing on research conducted among patients in Ireland, this article examines the narrative constructions of chronic kidney failure and explores the ways in which patient narratives cross-cut and subvert modernist medical constructions of transplantation as a therapeutic outcome, an endgame, a “gift of life.” In experience, patients dismantle this construction structure by emplotting their stories around the painful lack of an ending, ardently brought to bear by the lived realities of immunosuppressant drug therapy, the silent fears of graft rejection, and the isolation of recipiency. They articulate, instead, stories that disclose a multi-directional flow between past and future therapeutic interventions, between the altering nature of the renal body and personal experience. These storied dimensions are phenomenologically embedded in the sensory and temporal aspects of this condition as essential elements of chronic illness and as organizational properties of patient narratives.     

Inadvertent Lead Placement In The Left Ventricle: A Case Report And Brief Review

Inadvertent lead placement in the left ventricle (LV) is an uncommon and often under-diagnosed complication of cardiac device implantation. Thromboembolic (TE) events are common and usually secondary to fibrosis or thrombus formation on or around the lead. Anticoagulation can prevent TE events. Percutaneous and surgical LV lead extractions have been performed successfully, but the risks of percutaneous lead removal are not well-defined. In this report, we describe a case of inadvertent LV lead placement and briefly review the contemporary literature.     

Radiofrequency Catheter Ablation Of Atrioventricular Nodal Reentry Tachycardia In A Patient With Inferior Vena Cava Anomaly

Curative radiofrequency catheter modification of the slow pathway is the recommended therapy for patients suffering from recurrent symptomatic atrioventricular nodal reentry tachycardia. This is usually performed via femoral vein and the inferior vena cava (IVC). Presence of venous occlusion or complex venous anomaly involving the IVC may preclude this approach. Here, we report a case with a complex venous anomaly involving the inferior vena cava, who underwent electrophysiological study and successful radiofrequency ablation by an alternative approach.     

Noncryogenic Preservation of Mammalian Tissues for DNA Extraction: An Assessment of Storage Methods

Reliable field methods for the storage of tissues to be used for DNA extraction and amplification are critical to many studies employing molecular techniques. Protection from DNA degradation was compared among three commonly used methods of noncryogenic storage of tissues over a time scale of 2 years. All three methods prevented DNA degradation during storage for at least 6 months. DMSO (dimethyl sulfoxide)-salt solution provided the best protection from DNA degradation of tissues stored for up to 2 years. High molecular weight DNA was recovered from lysis buffer in which tissue was stored for 2 years, however, moderate amounts of degraded DNA was also present. High molecular weight DNA was recovered from tissues stored in ethanol for 2 years, however, the yield was relatively small compared to the other two noncryogenic storage techniques. Much of the DNA degradation in ethanol preserved tissues appeared to occur during the extraction procedure and can be reduced by soaking the tissue in lysis buffer for a few hours prior to beginning the extraction. The yield of PCR products was greatest from DNA extracted from DMSO-salt solution preserved tissues, whereas DNA from tissues stored in either lysis buffer or ethanol produced lower yields.     

An Improved Methodology to Overcome Key Issues in Human Fecal Metagenomic DNA Extraction

Microbes are ubiquitously distributed in nature, and recent culture-independent studies have highlighted the significance of gut microbiota in human health and disease. Fecal DNA is the primary source for the majority of human gut microbiome studies. However, further improvement is needed to obtain fecal metagenomic DNA with sufficient amount and good quality but low host genomic DNA contamination. In the current study, we demonstrate a quick, robust, unbiased,and cost-effective method for the isolation of high molecular weight(23 kb) metagenomic DNA(260/280 ratio 1.8) with a good yield(55.8 ± 3.8 ng/mg of feces). We also confirm that there is very low human genomic DNA contamination(eubacterial: human genomic DNA marker genes = 2~(27.9):1) in the human feces. The newly-developed method robustly performs for fresh as well as stored fecal samples as demonstrated by 16 S r RNA gene sequencing using 454 FLX+.Moreover, 16 S r RNA gene analysis indicated that compared to other DNA extraction methods tested, the fecal metagenomic DNA isolated with current methodology retains species richnessand does not show microbial diversity biases, which is further confirmed by q PCR with a known quantity of spike-in genomes. Overall, our data highlight a protocol with a balance between quality,amount, user-friendliness, and cost effectiveness for its suitability toward usage for cultureindependent analysis of the human gut microbiome, which provides a robust solution to overcome key issues associated with fecal metagenomic DNA isolation in human gut microbiome studies.     

大白菜线粒体DNA有效、快速提取方法

目的:建立一种有效、快捷的大白菜线粒体DNA(mtDNA)提取方法。方法:采用差速离心和蔗糖衬垫相结合的方法先从大白菜胞质雄性不育系及保持系叶片中分离出线粒体,然后用SDS—蛋白酶K裂解法提取mtDNA。结果:琼脂糖凝胶电泳表明,采用该方法提取的mtDNA片段大小在30~45kb之间,电泳条带清晰,无明显降解发生;以提取的mtDNA为模板进行RAPD反应,不育系和保持系均扩增出较多的条带,而且呈现出丰富的多态性,大小分布在500bp-3000bp之间,且条带清晰,没有脱尾现象。结论:该方法提取mtDNA,省时、省钱,对实验设备要求较低,而且分离出的mtDNA质量较高,能满足后续分子生物学研究工作需要。     

Radiofrequency Ablation Of Typical Atrial Flutter Via Right Subclavian/jugular Vein Access In A Patient With Implanted Filter In The Inferior Vena Cava

Radiofrequency ablation of Cavotricuspid Isthmus-dependent Atrial Flutter (CTI AFL), a usual and safe therapeutic procedure in interventional electrophysiology with a high success rate, aiming to induce permanent block of conduction over CTI, is normally performed via the femoral access, which allows practical access to the CTI through the inferior vena cava (IVC). In rare cases of obstruction of IVC, ablation of CTI can be performed only through the superior vena cava (SVC) access. We present a case of typical atrial flutter that was ablated through the right subclavian/jugular veins because of iatrogenic obstruction of the IVC due to a previously implanted thrombus filter. Furthermore we discuss about how we resolved access-related problems of instability during catheter ablation on CTI.     

Unusual Pauses In Sinus rhythm And Intermittent 2 to 1 AV Block In A Patient With Concealed His Extra Systoles - A Rare Cause Of Bradycardia

A 56 year old male with a past medical history of hypertension and dyslipidemia presented with recurrent dizziness. Routine EKG was performed, which suggested frequent junctional extra systoles with compensatory pauses. During telemetry periods of 2:1 block with effective ventricular rate of 34 bpm was observed. His bundle study suggested frequent His extra systoles causing functional AV block. Treatment with anti-arrhythmic medication, paradoxically improved AV block and symptoms in our patient.     

An In Vitro Procedure for Estimation of Lead Relative Bioavailability: With Validation

The relative bioaccessibility leaching procedure (RBALP) is a simple, reproducible, and rapid in vitro procedure for estimating the in vivo (juvenile swine) relative bioavailability (RBA) of lead in solid media. Control of pH, temperature, and agitation are the most critical parameters of this in vitro procedure. The performance of the method was evaluated by triplicate analyses of each of 19 different test substances by the author and three independent laboratories, and comparison of the results to relative bioavailability (RBA) values measured in vivo. The results indicate that the RBALP measurements are strongly correlated with the in vivo RBA values (r² = 0.924, p < 0.0001), with an average absolute error of 10% and an average predictive error of 20%. Comparison of results within and between laboratories indicates that the procedure is highly reproducible, with inter-and intra-laboratory coefficients of variation of 4% and 6%, respectively, and within-sample precision of approximately 7%. Based on the results reported here, the RBALP can be effective in providing reliable estimates of lead RBA as predicted by the immature swine model. The method may also be valuable in evaluating site-specific differences in bioaccessibility, assessing remedial technologies intended to reduce lead RBA, providing a screening mechanism for futurein vivo studies, and providing insight into the chemical and physical factors that control lead bioavailability.     

Proboscidean DNA from Museum and Fossil Specimens: An Assessment of Ancient DNA Extraction and Amplification Techniques

Applications of reliable DNA extraction and amplification techniques to postmortem samples are critical to ancient DNA research. Commonly used methods for isolating DNA from ancient material were tested and compared using both soft tissue and bones from fossil and contemporary museum proboscideans. DNAs isolated using three principal methods served as templates in subsequent PCR amplifications, and the PCR products were directly sequenced. Authentication of the ancient origin of obtained nucleotide sequences was established by demonstrating reproducibility under a blind testing system and by phylogenetic analysis. Our results indicate that ancient samples may respond differently to extraction buffers or purification procedures, and no single method was universally successful. A CTAB buffer method, modified from plant DNA extraction protocols, was found to have the highest success rate. Nested PCR was shown to be a reliable approach to amplify ancient DNA templates that failed in primary amplification.     

Microwave-Assisted Extraction of Wax from Oily Sludge: An Experimental Study and its Process Variables Optimization Using Response Surface Methodology

The wax present in petroleum sludge, generated by refineries and at crude production sites, consists of paraffin hydrocarbons (C18–C36) known as paraffin wax and naphthenic hydrocarbons (C30–C60). The present study is aimed at the recovery of wax from petroleum oily sludge by microwave-assisted solvent extraction using a Toluene/MEK mixture and subsequently de-crystallizing the wax. The process variables affecting the microwave-assisted solvent extraction are optimized for recovery of wax. The simultaneous effects of process variables such as irradiation time (2–10 minutes), solvent to sludge ratio (40–80 wt%), reactant volume (100–300 ml), and microwave power (80–400 W) on the recovery of wax were evaluated. A central composite design and response surface methodology were used for the optimization of the extraction process. Based on the central composite design, quadratic models were developed to correlate the extraction process variables with the responses and the models were analyzed using appropriate statistical methods for analysis of variance. Optimization of process variables shows the maximum recovery of wax was about 79.57% at 300 ml of reactant volume with microwave power output of 400 W at 7.6 minutes of retention time with 56.56% of Toluene/MEK to sludge ratio.     

Improvement in the In Vivo Digestibility of Rice Protein by Alkali Extraction Is Due to Structural Changes in Prolamin/Protein Body-I Particle

Rice prolamin, constituting type-I protein body (PB-I), is indigestible and causes deterioration of rice protein nutritional quality. In this study, the in vivo digestibility of rice protein isolates was investigated by tracing their intraluminal transit in the gastrointestinal (GI) tract of rats by western blotting and by observing the structures excreted in the feces by electron microscopy. Two types of rice protein isolates, produced by alkali extraction (AE-RP) and by starch degradation (SD-RP), were compared. The protein patterns in the isolates were similar, but their digestion in the GI-tract showed striking differences. In the AE-RP group, 13-kDa prolamin (13P) quickly disappeared in the lower GI tract and was not excreted in the feces. By contrast, in the SD-RP group, 13P accumulated massively and nearly intact PB-Is were excreted. These results indicate that the in vivo digestibility of prolamin can be improved by alkali extraction through structural changes to it.