Evaluation of Hyaluronic Acid Dilutions at Different Concentrations Using a Quartz Crystal Resonator (QCR) for the Potential Diagnosis of Arthritic Diseases

The main objective of this article is to demonstrate through experimental means the capacity of the quartz crystal resonator (QCR) to characterize biological samples of aqueous dilutions of hyaluronic acid according to their viscosity and how this capacity may be useful in the potential diagnosis of arthritic diseases. The synovial fluid is viscous due to the presence of hyaluronic acid, synthesized by synovial lining cells (type B), and secreted into the synovial fluid thus making the fluid viscous. In consequence, aqueous dilutions of hyaluronic acid may be used as samples to emulate the synovial fluid. Due to the viscoelastic and pseudo-plastic behavior of hyaluronic acid, it is necessary to use the Rouse model in order to obtain viscosity values comparable with viscometer measures. A Fungilab viscometer (rheometer) was used to obtain reference measures of the viscosity in each sample in order to compare them with the QCR prototype measures

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Artificial synovial fluid and artificial cerebrospinal fluid development and tests using QCR based biosensor for medical diagnosis

Quartz Crystal Resonators are devices with high capabilities in sensing systems due to their accuracy, efficiency and low cost. In this work we present a prototype of biosensor based on the use of QCR with the objective of measure the viscosity of small samples of biological fluids for medical diagnosis. In order to observe the response of the system in a biomedical application, two artificial fluids were developed for simulate healthy and pathological fluids. These measurements were compared with a professional viscometer to observe the similarity between both measurement methods. These tests may be used to observe the viability of the device and to calibrate the system before testing with real fluids

Viscosity Measurement Sensor: A Prototype for a Novel Medical Diagnostic Method Based on Quartz Crystal Resonator

Viscosity variation in human fluids, such as Synovial Fluid (SF) or Cerebrospinal Fluid (CSF), can be used as a diagnostic factor; however, the sample volume obtained for analysis is usually small, making it difficult to measure its viscosity. On the other hand, Quartz Crystal Resonators (QCR) have been used widely in sensing applications due to their accuracy, cost, and size. This work provides the design and validation of a new viscosity measurement system based on quartz crystal resonators for low volume fluids, leading to the development of a sensor called “ViSQCT” as a prototype for a new medical diagnostic tool. The proposed method is based on measuring the resonance frequency at the crystal’s maximum conductance point through a frequency sweep, where crystals with 10 MHz fundamental resonance frequency were used. For validation purposes, artificial fluids were developed to simulate SFs and CFs in healthy and pathological conditions as experiment phantoms. A commercial QCR based system was also used for validation since its methodology differs from ours. A conventional rotational viscometer was used as a reference for calibration purposes. ViSQCT demonstrates the capability to measure the sample’s viscosity differentiation between healthy and pathological fluid phantoms and shows that it can be used as a basis for a diagnostic method of several pathologies related to the studied biological fluids. However, some performance differences between both QCR-based systems compared to the reference system deserves further investigation

Preliminary Glycerine Tests using Quartz Crystal Resonator based biosensor for medical diagnosis

Quartz crystal resonators (QCR) are piezoelectric elements that, when excited with a sinusoidal signal at its resonance frequency, their impedance will reach a minimum value. According to Sauerbrey [1] and Kanazawa [2], when the crystal is in contact with a mass (solidf ilm) or with a fluid, its resonance frequency changes. These properties allow QCR to have applications in the field of biomedicine [3]. With this prototype it will be possible to measure the viscosity of biological fluids for medical diagnosis, for example, synovial fluid, since the viscosity is a factor in diagnosing diseases such as osteoarthritis or arthritis [4, 5]. On a first stage, we must make sure that the device is capable of measuring viscosity. For this purpose, tests were developed to measure the viscosity of a Newtonian fluid such as a mixture of vegetable glycerin with distilled water

Identification and description of controlled clinical trials published in Spanish Ophthalmology Journals

<p><b><i>Purpose</i></b>: Properly conducted controlled clinical trials (CCTs) provide the highest level of evidence for optimising decision-making in healthcare. Electronic search strategies do not exhaustively retrieve them, because of issues related to indexing, exclusion of journals in languages other than English, among others. A handsearch approach is therefore warranted. We aimed to identify all CCTs published in Ophthalmology journals in Spain, to describe their main features, and to submit them to the Cochrane Register of CCTs (CENTRAL).</p> <p><b><i>Methods</i></b>: After identifying all Spanish Ophthalmology Journals, we conducted a systematic handsearch following Cochrane guidelines. When appropriate, results were compared against electronic searches. A descriptive analysis was completed, including risk of bias assessment.</p> <p><b><i>Results</i></b>: We identified 18 eligible journals; 10 074 original articles, editorials, letters to the editor, abstracts and conference proceedings were assessed via handsearching for inclusion. Of these, 136 were subject to title and abstract screening, after which 102 were classified as CCTs. We identified three articles via electronic searches that had not been detected via handsearch, for a total of 105 CCTs. Among these, the most investigated pathologies were cataracts (32/105; 30.5%) and glaucoma (23/105 21.9%). Regarding risk of bias, 104/105 (99.0%) were deemed as “high risk of bias”, mainly due to flaws in sequence generation and allocation concealment. 15/105 (14.3%) mentioned conflicts of interest, half of which had something to declare. No CCT reported adherence to CONSORT.</p> <p><b><i>Conclusion</i></b>: Spanish Ophthalmology journals publish a low number of CCTs, with limited methodological quality. Handsearching was more sensitive than the electronic searching.</p> <p><b>Abbreviations</b> CCT: Controlled clinical trial</p

Inhibition of chymotrypsin-like activity of the proteasome by ixazomib prevents mitochondrial dysfunction during myocardial ischemia

The heart is critically dependent on mitochondrial respiration for energy supply. Ischemia decreases oxygen availability, with catastrophic consequences for cellular energy systems. After a few minutes of ischemia, the mitochondrial respiratory chain halts, ATP levels drop and ion gradients across cell membranes collapse. Activation of cellular proteases and generation of reactive oxygen species by mitochondria during ischemia alter mitochondrial membrane permeability, causing mitochondrial swelling and fragmentation and eventually cell death. The mitochondria, therefore, are important targets of cardioprotection against ischemic injury. We have previously shown that ixazomib (IXA), a proteasome inhibitor used for treating multiple myeloma, effectively reduced the size of the infarct produced by global ischemia in isolated rat hearts and prevented degradation of the sarcoplasmic reticulum calcium release channel RyR2. The aim of this work was to further characterize the protective effect of IXA by determining its effect on mitochondrial morphology and function after ischemia. We also quantified the effect of IXA on levels of mitofusin-2, a protein involved in maintaining mitochondrial morphology and mitochondria-SR communication. We found that mitochondria were significantly preserved and functional parameters such as oxygen consumption, the ability to generate a membrane potential, and glutathione content were improved in mitochondria isolated from hearts perfused with IXA prior to ischemia. IXA also blocked the release of cytochrome c observed in ischemia and significantly preserved mitofusin-2 integrity. These beneficial effects resulted in a significant decrease in the left ventricular end diastolic pressure upon reperfusion and a smaller infarct in isolated hearts.Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1110257 1130407 11170962 118061