Kinetic analysis,size profiling,and bioenergetic association of DNA released by selected cell lines in vitro

Although circulating DNA (cirDNA) analysis shows great promise as a screening tool for a wide range of pathologies, numerous stumbling blocks hinder the rapid translation of research to clinical practice. This is related directly to the inherent complexity of the in vivo setting, wherein the influence of complex systems of interconnected cellular responses and putative DNA sources creates a seemingly arbitrary representation of the quantitative and qualitative properties of the cirDNA in the blood of any individual. Therefore, to evaluate the potential of in vitro cell cultures to circumvent the difficulties encountered in in vivo investigations, the purpose of this work was to elucidate the characteristics of the DNA released [cell-free DNA (cfDNA)] by eight different cell lines. This revealed three different forms of cfDNA release patterns and the presence of nucleosomal fragments as well as actively released forms of DNA, which are not only consistently observed in every tested cell line, but also in plasma samples. Correlations between cfDNA release and cellular origin, growth rate, and cancer status were also investigated by screening and comparing bioenergetics flux parameters. These results show statistically significant correlations between cfDNA levels and glycolysis, while no correlations between cfDNA levels and oxidative phosphorylation were observed. Furthermore, several correlations between growth rate, cancer status, and dependency on aerobic glycolysis were observed. Cell cultures can, therefore, successfully serve as closed-circuit models to either replace or be used in conjunction with biofluid samples, which will enable sharper focus on specific cell types or DNA origins.     

Proliferationen der Fischepidermis nach der Einwirkung von inhibitoren des glykolytischen Energiestoffwechsels

Summary When fluoride-ions or monoiodoacetate is added to the ambient medium, there occur in fish larvae after 12 h, and in eels after 24 h, in some places, solid epidermal proliferations. The effect of glycolysis inhibitors on epidermal mitotic activity might be due to an impairment of energy metabolism as it is nullified by a simultaneous application of inorganic diphosphate or by doubled O₂ partial pressure of 320 mm Hg.     

Systemic methods for the analysis of failure

For more than 20 years systems-related ideas have been used to analyze and model failures and disasters of various sorts. The authors outline some examples of the links that have been forged between failures and systems over this period. An overview of the origins and development of systems failures teaching and research at the United Kingdom Open University is also presented, together with two systemic methodologies for the analysis of failure that have stemmed from this work. The implications of recent research on the application of the more sophisticated of these two methodologies are also discussed.     

Fulminant hypertension in transgenic rats harbouring the mouse Ren-2 gene

PRIMARY hypertension is a polygenic condition in which blood pressure is enigmatically elevated; it remains a leading cause of cardiovascular disease and death due to cerebral haemorrhage, cardiac failure and kidney disease. The genes for several of the proteins involved in blood pressure homeostasis have been cloned and characterized, including those of the renin-angiotensin system, which plays a central part in blood pressure control. Here we describe the introduction of the mouse Ren-2 renin gene into the genome of the rat and demonstrate that expression of this gene causes severe hypertension. These transgenic animals represent a model for hypertension in which the genetic basis for the disease is known. Further, as the transgenic animals do not overexpress active renin in the kidney and have low levels of active renin in their plasma, they also provide a new model for low-renin hypertension.     

(Na/ + K+)ATPase has one functioning phosphorylation site per alpha subunit

(Na+ + K+)ATPase contains two different subunits, a catalytic subunit (alpha) and a subunit with uncertain function (beta). The enzyme binds ATP, ouabain and vanadate, and can be phosphorylated by ATP as well as by inorganic phosphate. From the previously reported maximal binding and phosphorylation capacities of 3.5--4.3 nmol P per mg protein (based on Lowry protein determination) and the earlier molecular weight value of approximately 250,000, a molar binding and phosphorylation capacity of 0.87--1.07 mol per mol enzyme was derived. As it is generally agreed that the enzyme molecule contains two alpha subunits or even a multiple of two, it has been suggested that the enzyme operates by means of a so-called "half-of-the-sites mechanism" whereby only of the two alpha subunits can be phosphorylated at any one time. We now present evidence that every alpha subunit can be phosphorylated simultaneously, which rules out the operation of such a mechanism.