Rapid and Efficient Enrichment of Snake Venoms from Human Plasma Using a Strong Cation Exchange Tip Column to Improve Snakebite Diagnosis

Snake envenomation is a serious public health issue in many tropical and subtropical countries. Accurate diagnosis and immediate antivenom treatment are critical for effective management. However, the venom concentration in the victims’ plasma is usually low, representing one of the bottlenecks in developing clinically applicable assays for venom detection and snakebite diagnosis. In this study, we attempted to develop a simple method for rapid enrichment of venom proteins from human plasma to facilitate detection. Our experiments showed that several major protein components of both Naja atra (N. atra) and Bungarus multicinctus (B. multicinctus) venoms have higher isoelectric point (pI) values relative to high-abundance human plasma proteins and could be separated via strong cation exchange–high-performance liquid chromatography (SCX-HPLC). Based on this principle, we developed an SCX tip column-based protocol for rapid enrichment of N. atra and B. multicinctus venom proteins from human plasma. Application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) led to the identification of cytotoxin and beta-bungarotoxin as the major proteins enriched by the SCX tip column in each venom sample. The entire process of venom enrichment could be completed within 10–15 min. Combination of this method with our previously developed lateral flow strip assays (rapid test) significantly enhanced the sensitivity of the rapid test, mainly via depletion of the plasma protein background, as well as increase in venom protein concentration. Notably, the SCX tip column-based enrichment method has the potential to efficiently enrich other Elapidae snake venoms containing proteins with higher pI values, thereby facilitating venom detection with other assays. This simple and rapid sample preparation method should aid in improving the clinical utility of diagnostic assays for snakebite.     

Five-year survival of patients after out-of-hospital cardiac arrest depending on age

Patient's age belongs to the independent prognostic factors of patients after out-of-hospital cardiac arrest (OHCA). This study aimed to evaluate the influence of age on 5-year survival in professionally cardio-pulmonary resuscitated patients with “primary cardiac” etiology OHCA. In this analysis of prospective multi-centric study, from April 1, 2002 until August 31, 2004, a total of 560 patients were included (aged 16-97 years) from the East Bohemian region, for whom a professional cardio-pulmonary resuscitation for OHCA was attempted. In the age subgroup <70 years there were 307 patients and in the age subgroup ≥70 years there were 253 patients. Of the subgroup <70 years, 29 patients (10%) survived to year 5 (58% from the 50 patients surviving to day 30), and in the subgroup ≥70 years, we had 4 patients surviving to year 5 (2%) (29% from the 14 patients surviving to day 30), respectively (Fisher‘s exact test; comparison in the all resuscitated patients: p < 0.001, in the population surviving to day 30: p = 0.071). In conclusion, there was a trend towards a worse outcome in 5-year survival following OHCA in the patients aged ≥70 years. Nevertheless, these data support that prognosis OHCA of elders is not associated with universal dismal outcome.     

Effet d’un effort intermittent d’intensité variable sur la variation du QT et du risque de mort subite chez des élèves camerounais

IntroductionSeveral cases of sudden deaths are observed among students practicing sport and physical activity (SPA). Just few studies have been carried out on the variation of the QT (interval) and risk of sudden death during sporting exercises.AimTo determine the effect of variable intermittent stress intensity on the variation of QT and the risk of sudden cardiac death.Patients and methodsForm 4, lower sixth and upper sixth students were recruited from a high school in Douala (Cameroon). Each subject was tested; starting with a 2-km walk followed by a sprint race or an endurance race, protocol I (P1) or the reverse; protocol II (P2). Two electrocardiograms were recorded; prior to the beginning of the SPA and 5 minutes after the last race. QT was corrected using four formulas.ResultsForty-one subjects (21 women and 20 men), mean age 18 ± 2 years were recruited. At the end of the exercise, corrected QT increased with Bazzet's formula and decreased with Frahmingam's formula. The difference was not significant with Fridericia and Hodges formulas. The frequency of long QT was higher at the end of the exercise with Bazzet's formula (12.2% vs. 24.4%, P = 0.009) while the difference was not significant for the other formulas.ConclusionThe risk of sudden cardiac death increases significantly after SPA. More studies on large samples are needed.     

Hypertrophy of lymphoid organs is a possible phenotypic characteristic of R420W mutation of the cardiac ryanodine receptor gene: A study using a knock-in mouse model

Cardiac ryanodine receptor gene (RyR2) mutations sometimes result in sudden cardiac death due to fatal arrhythmias. N-terminal R420W mutation of RyR2 is known to show similar phenotypes to arrhythmogenic right ventricular cardiomyopathy and to cause juvenile sudden death. We previously reported two sudden death cases with the same R420W mutation. Interestingly, the cases showed hypertrophy of lymphoid organs such as the thymus and mesenteric lymph nodes. The present study examined whether R420W mutation of RYR2 causes hypertrophy of lymphoid organs by generating a mouse model carrying the mutation. Homozygous (RyR2^R420W/R420W) mice showed significant increases in thymus and spleen weights but not in kidney, heart, and brain weights compared with wild-type mice. The mice also showed remarkable hypertrophy of mesenteric lymph nodes. Immunohistochemical study revealed that RyR2 protein was prominently expressed in epithelial cells of the thymic medulla in the thymus. These findings show that mice with R420W mutation of RyR2 exhibit hypertrophy of lymphoid organs. Sudden unexplained death cases with the mutation may display such findings at autopsy.