Tehran University Medical Journal

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Cystic fibrosis (CF) is the most common autosomal recessive genetic disease, which is caused by defection in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. CFTR gene codes chloride channels to modulate the homeostasis of epithelial environments. Defective CFTR affects various organs such as the lungs, pancreas, intestine, liver and skin; however, lung impairment is the main reason for mortality in these patients. About 2000 mutations in this gene have been discovered, but nearly 150 mutations lead to serious symptoms. CFTR mutations are classified into six major classes based on phenotypic manifestations such as structural instability of channels, defective processing, malfunctioning chloride-ion transfers and decreased number of chloride channels in the cell membranes. These cause various symptoms such as respiratory infection, intestinal obstruction, pancreatic exocrine insufficiency and malabsorption. Significant improvements in diagnostic tools and methods such as newborn screening, chloride sweat test and gene sequencing have increased the incidence and the prevalence of CF. Enormous studies have also been done on CF recognition and treatment procedures, which have resulted in 30 years of growth in the life expectancy of the patients. Despite the recent achievements, due to the high complexity of this disease and the involvement of various organs, the available treatments are nonpermanent. In the past few years, new combinatorial drugs have been introduced which potentiate and correct CFTR and ameliorate the CF symptoms. Recently, novel genetic engineering methods like CRISPR/Cas9 and TALEN have been utilized to correct the mutated CFTR gene with high accuracy and eradicate the symptoms. Studying this disease at its distinct levels from subcellular to organs could help to find new treatments. Systematic research in finding common attributes between different states of the disease is very beneficial. Interdisciplinary research groups with various expertise in mathematics, biology and engineering could have a great impact on describing the full picture of the disease and development of new treatment strategies. The main part of this article provides a comprehensive overview of cystic fibrosis with emphasis on the key studies on genetics and their effects on cellular and physiological levels. In this work, conventional and new treatment methods have also been discussed.

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Results: Overall, 57 patients were evaluated of whom 72% (41 patients) were male. The mean age was 49.9±19.8 (median 53, range 18-94) years. The mean length of stay in the ICU was 13.5±17.5 (median 7, range: 75-75) days. The mortality rate was 17.5% (10 patients). The scores of SOFA, SAPS II, APACHE II, and APACHE IV were significantly higher in deceased patients than in discharged ones. The highest diagnostic accuracy (area under the curve) for all four predicting tools was observed in the second week of hospitalization. On the other hand, SAPS II (74%) on the first day, APACHE-II (76%) on the second day, APACHE-II (82%) on the third day, SOFA (77%) on day 4-5, and SAPS II (82%) on day 6-7 had the highest diagnostic accuracy. Conclusion: In the present study scores of all four mortality predicting tools at admission were significantly associated with mortality. The accuracy of SAPS II, APACHE IV, and APACHE II are appropriate for estimating prognosis, especially after the second week of admission.

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The recording of electrophysiological activities of brain neurons in the last half-century has been considered as one of the effective tools for the development of neuroscience. One of the techniques for recording the activity of nerve cells is the multi-electrode arrays (MEAs). Microelectrode arrays (MEAs) are usually employed to record electrical signals from electrogenic cells like neurons or cardiomyocytes. MEAs consist of an array of planar or three-dimensional electrodes that act as electrical interfaces and record cellular signals or stimulate cells. These platforms can be used in different applications including neuroscience studies, prostheses and rehabilitation, deep brain stimulation (DBS), cardiac pacemakers, retinal and cochlear implants, or for brain-computer interfaces (BCI) in general. Multi-electrode arrays are known as long-term recording and non-invasive devices. The MEA structure includes arrays of electrodes with micrometer and nanometer dimensions which are designed to stimulate and record the electrical activity of cells, and are fabricated using micromachining technologies. MEAs should be biocompatible to serve as a substrate for cell growth. On the other hand, they must have low impedance to be able to provide a high signal-to-noise ratio, and small size to offer a suitable spatial resolution for recording. MEAs are usually fabricated on glass substrates patterned with high-conductivity metals such as gold, iridium or platinum, which are insulated with a biocompatible layer. Despite fast progress, current multi-electrode arrays for neural applications still face limitations such as low signal-to-noise ratio and spatial resolution. To achieve better spatial resolution and lower noise levels and therefore more accurate signal, it is necessary to develop arrays with smaller sizes and lower impedance. Meanwhile, many nanostructures such as graphene, carbon nanotubes, gold nanoparticles, and also conductive polymers have become attractive candidates for this application due to their interesting properties. In this paper, the technology of multi-electrode arrays, how it works and its various parts are introduced, and finally, the challenges and developments in this field are investigated. Multi-electrode array technology is used for neuroscience research, neural network analysis, drug effects screening, and neural prosthesis studies.