KCNE3 mutation V17M identified in a patient with lone atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac rhythm disorder with a lifetime risk for development of 25% for people aged 40 or older. In this study we aim for the functional assessment of a mutation in KCNE3 identified in a proband with early-onset lone AF. METHODS: Screening of genomic DNA from the proband led to identification of a KCNE3 V17M missense mutation. We heterologously expressed the accessory channel subunit in Xenopus laevis oocytes together with its known interacting potassium channel alpha-subunits. Further, we applied RT-PCR on human total RNA from left and right atria and ventricle. RESULTS: Electrophysiological recordings revealed an increased activity of Kv4.3/KCNE3 and Kv11.1/KCNE3 generated currents by the mutation, thereby conferring susceptibility of mutation carriers to faster cardiac action potential repolarization and thus vulnerability to re-entrant wavelets in the atria and thereby AF. CONCLUSION: Here we report a novel mutation in KCNE3 identified in a proband with early-onset lone AF possibly leading to gain-of-function of several cardiac currents. We suggest abnormalities in the KCNE3 gene as a potential genetic risk factor for initiation and/or maintenance of AF.     

An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to hydroxychloroquine

In this work the susceptibility of mobile and cystic forms of Borrelia burgdorferi to hydroxychloroquine (HCQ) was studied. The minimal bactericidal concentration (MBC) of HCQ against the mobile spirochetes was >32 μg/ml at 37 °C, and >128 μg/ml at 30 °C. Incubation with HCQ significantly reduced the conversion of mobile spirochetes to cystic forms. When incubated at 37 °C, the MBC for young biologically active cysts (1-day old) was >8 μg/ml, but it was >32 μg/ml for old cysts (1-week old). Acridine orange staining, dark-field microscopy and transmission electron microscopy revealed that the contents of the cysts were partly degraded when the concentration of HCQ was ≥MBC. At high concentrations of HCQ (256 μg/ml) about 95% of the cysts were ruptured. When the concentration of HCQ was ≥MBC, core structures did not develop inside the cysts, and the amount of RNA in these cysts decreased significantly. Spirochetal structures inside the cysts dissolved in the presence of high concentrations of HCQ. When the concentration of HCQ was ≥MBC, the core structures inside the cysts were eliminated. These observations may be valuable in the treatment of resistant infections caused by B. burgdorferi, and suggest that a combination of HCQ and a macrolide antibiotic could eradicate both cystic and mobile forms of B. burgdorferi. Electronic Publication     

Quality by design approach for viral clearance by protein a chromatography

Protein A chromatography is widely used as a capture step in monoclonal antibody (mAb) purification processes. Antibodies and Fc fusion proteins can be efficiently purified from the majority of other complex components in harvested cell culture fluid (HCCF). Protein A chromatography is also capable of removing modest levels of viruses and is often validated for viral clearance. Historical data mining of Genentech and FDA/CDER databases systematically evaluated the removal of model viruses by Protein A chromatography. First, we found that for each model virus, removal by Protein A chromatography varies significantly across mAbs, while remains consistent within a specific mAb product, even across the acceptable ranges of the process parameters. In addition, our analysis revealed a correlation between retrovirus and parvovirus removal, with retrovirus data generally possessing a greater clearance factor. Finally, we describe a multivariate approach used to evaluate process parameter impacts on viral clearance, based on the levels of retrovirus‐like particles (RVLP) present among process characterization study samples. It was shown that RVLP removal by Protein A is robust, that is, parameter effects were not observed across the ranges tested. Robustness of RVLP removal by Protein A also correlates with that for other model viruses such as X‐MuLV, MMV, and SV40. The data supports that evaluating RVLP removal using process characterization study samples can establish multivariate acceptable ranges for virus removal by the protein A step for QbD. By measuring RVLP instead of a model retrovirus, it may alleviate some of the technical and economic challenges associated with performing large, design‐of‐experiment (DoE)—type virus spiking studies. This approach could also serve to provide useful insight when designing strategies to ensure viral safety in the manufacturing of a biopharmaceutical product. Biotechnol. Bioeng. 2014;111: 95–103. © 2013 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.     

Developmental Abnormalities of Female Sexual Organs in Swine

One thousand reproductive organs from gilts were collected during the period March-August at a slaughterhouse in central Sweden. The organs were inspected in respect of congenital defects and certain reproductive physiological data. The results are recorded in Tables 1–6. Figs. 1–7 show some types of malformations. The total frequency of malformations was 22.1 %, of which 14 % cysts in mesosalpinx and 4.1 % partial duplication of the vagina. The remainder consisted of general developmental defects and of local defects in the tubular genital tract. Malformations with presumed effect on fertility were found in 4.5 % of all organs examined, of which 0.8 % presumably caused permanent sterility and 3.7 % lowered fertility (small litters). Hydrometra was found in 33 cases, 2 of which in sexually mature gilts. The left ovary contained more corpora lutea than the right, and the mean weight of the left ovary was greater than that of the right, both in sexually mature and prepuberal gilts. Of 202 sexually mature gilts examined 16.9 % had cystic corpora lutea in their ovaries as a rule 2–4 in each ovary.     

A methodological basis for description and analysis of systems with complex switch-like interactions

 A wide range of complex systems appear to have switch-like interactions, i.e. below (or above) a certain threshold x has no or little influence on y, while above (or below) this threshold the effect of x on y saturates rapidly to a constant level. Switching functions are frequently described by sigmoid functions or combinations of these. Within the context of ordinary differential equations we present a very general methodological basis for designing and analysing models involving complicated switching functions together with any other non-linearities. A procedure to determine position and stability properties of all stationary points lying close to a threshold for one or several variables, so-called singular stationary points, is developed. Such points may represent homeostatic states in models, and are therefore of considerable interest. The analysis provides a profound insight into the generic effects of steep sigmoid interactions on the dynamics around homeostatic points. It leads to qualitative as well as quantitative predictions without using advanced mathematical methods. Thus, it may have an important heuristic function in connection with numerical simulations aimed at unfolding the predictive potential of realistic models. Received 25 January 1996; received in revised form 29 June 1997     

Inhibition of prostaglandin induced uterine activity in the second trimester of pregnancy by β-mimetic adrenergic agents

As a consequence of great individual variations among pregnant women in their response to prostaglandin medication, overstimulation of the uterus might occasionally occur. The need of a drug which could safely prevent excessive and undesirable prostaglandin-induced uterine contractions is therefore apparent.Two β-mimetic adrenergic compounds, orciprenaline and ritodrine, were tested with respect to their ability to reduce prostaglandin-induced uterine activity. Both compounds have successfully depressed the intensity, as well as the frequency of uterine contractions, which were previously induced by intrauterine administration of prostaglandin F_2α. With both drugs the reduction in uterine activity was closely dose-related and accompanied by a considerable increase in the maternal heart rate. While orciprenaline did not alter the maternal blood pressure, ritodrine produced a rise in systolic, and a fall in diastolic pressure. No other side effect was recorded. When the infusion ceased, uterine activity increased in various degrees.On the basis of the present findings the possible role of prostaglandins in the physiological regulation of the uterine contractions during pregnancy is discussed.     

Bringing science and pragmatism together a tiered approach for modelling toxicological impacts in LCA

Goal, Scope and Background  The EU 5^th framework project OMNIITOX will develop models calculating characterisation factors for assessing the potential toxic impacts of chemicals within the framework of LCA. These models will become accessible through a web-based information system. The key objective of the OMNIITOX project is to increase the coverage of substances by such models. In order to reach this objective, simpler models which need less but available data, will have to be developed while maintaining scientific quality. Methods. Experience within the OMNIITOX project has taught that data availability and quality are crucial issues for calculating characterisation factors. Data availability determines whether calculating characterisation factors is possible at all, whereas data quality determines to what extent the resulting characterisation factors are reliable. Today, there is insufficient knowledge and/or resources to have high data availability as well as high data quality and high model quality at the same time. Results  The OMNIITOX project is developing two inter-related models in order to be able to provide LCA impact assessment characterisation factors for toxic releases for as broad a range of chemicals as possible: 1) A base model representing a state-of-the-art multimedia model and 2) a simple model derived from the base model using statistical tools. Discussion. A preliminary decision tree for using the OMNIITOX information system (IS) is presented. The decision tree aims to illustrate how the OMNIITOX IS can assist an LCA practitioner in finding or deriving characterisation factors for use in life cycle impact assessment of toxic releases. Conclusions and Outlook  Data availability and quality are crucial issues when calculating characterisation factors for the toxicity impact categories. The OMNIITOX project is developing a tiered model approach for this. It is foreseen that a first version of the base model will be ready in late summer of 2004, whereas a first version of the simple base model is expected a few months later.     

Effects of leaf beetle damage on stem wood production in coppicing willow

1 The effect of defoliation by larvae of the leaf beetle Phratora vulgatissima on current‐year stem wood production of resprouting Salix viminalis was investigated for two years. Adjacent subplots with varying levels of defoliation within one large willow plantation in south Sweden were studied in the two years. 2 High defoliation levels reduced stem wood production by an average of 32 and 39% in the two years, respectively. 3 Medium defoliation levels reduced stem wood production by 16% in one year. In the other year, the stem wood production of medium‐defoliated stools did not differ significantly from stools exposed to low defoliation, i.e. there was full compensatory growth. 4 The main difference between the year with compensatory growth and the one without was that overall productivity was higher in the year with compensation. This finding forms the basis for a mechanistic model by which compensation could be accomplished. We propose that the major contribution to full compensation comes from an increased growth among intermediate‐sized shoots of medium‐defoliated stools relative to the corresponding shoots in stools exposed to low defoliation.