Quiescience as a mechanism for cyclical hypoxia and acidosis

Tumour tissue characteristically experiences fluctuations in substrate supply. This unstable microenvironment drives constitutive metabolic changes within cellular populations and, ultimately, leads to a more aggressive phenotype. Previously, variations in substrate levels were assumed to occur through oscillations in the hæmodynamics of nearby and distant blood vessels. In this paper we examine an alternative hypothesis, that cycles of metabolite concentrations are also driven by cycles of cellular quiescence and proliferation. Using a mathematical modelling approach, we show that the interdependence between cell cycle and the microenvironment will induce typical cycles with the period of order hours in tumour acidity and oxygenation. As a corollary, this means that the standard assumption of metabolites entering diffusive equilibrium around the tumour is not valid; instead temporal dynamics must be considered

Isolation of equine endothelial cells and life cell angiogenesis assay

Arterial or venous thromboses are frequent clinical complications with the risk of fatal progression. Recent studies suggest the disruption of angiogenesis in the course of thrombus resolution as the underlying pathomechanism. Very similar to the situation in human patients, equine vessels have been described to be particularly susceptible to thrombosis. In contrast to humans, equine donors are readily available to obtain organs and tissues for isolation of endothelial cells. Objective of this study was to isolate equine endothelial cells and develop an angiogenesis assay from primary cultures. Macrovascular endothelial cells were obtained from jugular veins and carotid arteries of nine horses, one of which suffered from inflammatory processes. After enzymatic isolation, the cells were incubated in different selective primary media. Phenotypic identification of endothelial cells was accomplished by morphology and positive staining to von Willebrand factor. The reliable, inexpensive, and standardized combination of methods presented here resulted in pure endothelial cultures for angiogenesis assays that can be used in any cell culture laboratory. Inverted phase microscopy and life cell imaging was used to characterize the stages of the angiogenic cascade of the endothelial cells. Life cell imaging gave new insights into the in vitro formation of capillary like structures including exocytosis of microparticles from endothelial cells before integration into the three-dimensional structure. We hypothesize that a specific population of endothelial cells showing a highly active migration pattern in life cell imaging might play a role in the resolution of thrombosis

Tumour vascularization: sprouting angiogenesis and beyond

Tumour angiogenesis is a fast growing domain in tumour biology. Many growth factors and mechanisms have been unravelled. For almost 30 years, the sprouting of new vessels out of existing ones was considered as an exclusive way of tumour vascularisation. However, over the last years several additional mechanisms have been identified. With the discovery of the contribution of intussusceptive angiogenesis, recruitment of endothelial progenitor cells, vessel co-option, vasculogenic mimicry and lymphangiogenesis to tumour growth, anti-tumour targeting strategies will be more complex than initially thought. This review highlights these processes and intervention as a potential application in cancer therapy. It is concluded that future anti-vascular therapies might be most beneficial when based on multimodal anti-angiogenic, anti-vasculogenic mimicry and anti-lymphangiogenic strategies

Elastic cavitation, tube hollowing, and differential growth in plants and biological tissues

Elastic cavitation is a well-known physical process by which elastic materials under stress can open cavities. Usually, cavitation is induced by applied loads on the elastic body. However, growing materials may generate stresses in the absence of applied loads and could induce cavity opening. Here, we demonstrate the possibility of spontaneous growth-induced cavitation in elastic materials and consider the implications of this phenomenon to biological tissues and in particular to the problem of schizogenous aerenchyma formation

Generation of Rabi frequency radiation using exciton-polaritons

We study the use of exciton-polaritons in semiconductor microcavities to generate radiation spanning the infrared to terahertz regions of the spectrum by exploiting transitions between upper and lower polariton branches. The process, which is analogous to difference-frequency generation (DFG), relies on the use of semiconductors with a nonvanishing second-order susceptibility. For an organic microcavity composed of a nonlinear optical polymer, we predict a DFG irradiance enhancement of $2.8\cdot10^2$, as compared to a bare nonlinear polymer film, when triple resonance with the fundamental cavity mode is satisfied. In the case of an inorganic microcavity composed of (111) GaAs, an enhancement of $8.8\cdot10^3$ is found, as compared to a bare GaAs slab. Both structures show high wavelength tunability and relaxed design constraints due to the high modal overlap of polariton modes.Comment: 8 pages, 7 figure

Excitonic spectral features in strongly-coupled organic polaritons

Starting from a microscopic model, we investigate the optical spectra of molecules in strongly-coupled organic microcavities examining how they might self-consistently adapt their coupling to light. We consider both rotational and vibrational degrees of freedom, focusing on features which can be seen in the peak in the center of the spectrum at the bare excitonic frequency. In both cases we find that the matter-light coupling can lead to a self-consistent change of the molecular states, with consequent temperature-dependent signatures in the absorption spectrum. However, for typical parameters, these effects are much too weak to explain recent measurements. We show that another mechanism which naturally arises from our model of vibrationally dressed polaritons has the right magnitude and temperature dependence to be at the origin of the observed data.Comment: 14 pages, 6 figur

Kounis Syndrome together with Myocardial Bridging Leading to Acute Myocardial Infarction at Young Age

Kounis syndrome, also named as “allergic angina syndrome,” is a diagnosis in which exposure to an allergen causes mostly coronary spasm and rarely plaque rupture, resulting in ischemic myocardial events. Myocardial bridging is defined as an intramural segment of a coronary artery and its systolic compression by overlying fibers. Myocardial bridging generally has a benign prognosis and mostly affects the mid portion of left anterior descending coronary artery. However, some cases with myocardial ischemia, infarction, and sudden death have also been reported. A 17-year-old boy presented to the clinic with acute anterolateral myocardial infarction after having first dose of clindamycin and diagnosed as Kounis syndrome. Further diagnostic workup of the patient showed myocardial bridging at the mid left anterior descending artery. In this report, we present the combination of Kounis syndrome and myocardial bridging leading to myocardial infarction at young age

Using Support Vector Machine For Classification And Feature Extraction Of Spam In Email

We provide an overview of recent and successful content-based e-mail spam filtering algorithms in this article. Our main focus is on spam filters based on machine learning and variants influenced by them. We report on significant ideas, methodologies, key endeavors, and the field's current state-of-the-art. The initial interpretation of previous work demonstrates the fundamentals of spam filtering and feature engineering in e-mail. We finish by looking at approaches, procedures, and evaluation standards, as well as exploring intriguing offshoots of recent breakthroughs and proposing directions of future research

The effect of bosentan on plasma ischemia-modified albumin levels in acute mesenteric ischemia

Objective: Our aim in this study was to examine the effects of bosentan, an orally active antagonist of endothelin A and B receptors, on plasma ischemia-modified albumin (IMA) levels in mesenteric ischemia induced rats. Material and Method: In this randomized, controlled trial 36 mature female wistor rats were divided into three groups. Group 1 (n=12) was the control group which only laparotomy was performed. Group 2 (n=12) was the ischemia group and group 3 (n=12) was the bosentan pretreated (100 mg/kg-1 day, 1 gavage/day for two days before surgery) ischemia group. In the ischemia groups (GR 2 and GR 3) following laparotomy the superior mesenteric artery was clamped using a bulldog clamp during laparotomy. Blood samples were taken at 30 minutes from all groups and IMA levels were studied. Results: Plasma IMA levels in the ischemia group (GR 2) was significantly higher compared to those of the control (p<0.001) and bosentan pretreated group (GR 3) (p=0.002). Serum IMA levels were higher in GR 3 than control group but there were no statistical significance (p=0.659). Conclusion: These preliminary results suggest that bosentan might have a protective effect in mesenteric ischemic conditions

Classification of Mammogram Images by Using SVM and KNN

Breast cancer is a fairly diverse illness that affects a large percentage of women in the west. A mammogram is an X-ray-based evaluation of a woman's breasts to see if she has cancer. One of the earliest prescreening diagnostic procedures for breast cancer is mammography. It is well known that breast cancer recovery rates are significantly increased by early identification. Mammogram analysis is typically delegated to skilled radiologists at medical facilities. Human mistake, however, is always a possibility. Fatigue of the observer can commonly lead to errors, resulting in intraobserver and interobserver variances. The image quality affects the sensitivity of mammographic screening as well. The goal of developing automated techniques for detection and grading of breast cancer images is to reduce various types of variability and standardize diagnostic procedures. The classification of breast cancer images into benign (tumor increasing, but not harmful) and malignant (cannot be managed, it causes death) classes using a two-way classification algorithm is shown in this study. The two-way classification data mining algorithms are utilized because there are not many abnormal mammograms. The first classification algorithm, k-means, divides a given dataset into a predetermined number of clusters. Support Vector Machine (SVM), a second classification algorithm, is used to identify the optimal classification function to separate members of the two classes in the training dat