Applications and Biological Functions of Exosomes: A Comprehensive Review

Exosomes are also known as extracellular vesicles (EVs) which is bounded by a membrane mostly seen in eukaryotic cells secreted within the endosomal compartment along with some of the selected composition of RNA, proteins, lipids and DNA. They are capable of transferring signals among cells therefore it is used as a mediator for cell-to-cell communication. Exosomes helps in the excretion of cellular waste from the body. Exosomes possess various widespread activity in many of the biological functions such as transferring the biomolecules like enzymes, proteins, ribonucleic acid, lipids and also in the regulation of various pathological and physiological process in various diseases. Exosomes are released in to the in vitro growth medium with the help of cultured cells. They are said to be identified in coined matrix and tissue matrix. They are also identified in some of the biological fluids such as cerebrospinal fluid, urine, blood. Exosomes are considered as promising biomarkers in identification and treatment of many diseases as they contribute a lot in the diagnosis of various therapies. The efficacy and stability of imaging probes and therapeutics are enhanced by its biocompatible nature. Exosomes play a major role because of their use in the field of clinical application. It is important to understand the molecular mechanism behind their function and transport in order to explore more about exosomes. Here we discuss about the review and advancement done in the field of exosomes along with their biomedical applications, isolation techniques and biological functions.

Regeneration and Diagnosis of Kidney Disease Using Exosomes

: A growing global prevalence of acute kidney injury (AKI) and chronic kidney disease (CKD), high costs of kidney transplantation, a shortage of kidney donors, and low survival rate after dialysis have popularized mesenchymal stem cell (MSC) therapy via transplantation. However, the risks of tumorigenesis, immune rejection, pathogen transmission, loss of differentiation, and morphological changes after long-term culture have prompted researchers to develop a safer and more effective therapy method. Therefore, cell-free approaches have been developed to reduce the risks associated with stem cell-based therapies. In cell-free therapy of AKI and CKD, MSC-derived extracellular vesicles, with nanometer sizes, are used, called exosomes. Exosomes have a lipid bilayer membrane with various genes, microRNAs, and proteins for kidney repair. As known, MSC-derived exosomes have improved the kidney regeneration process for various reasons, such as increased safety and reduced inflammation, immune rejection, and tumorigenesis. With the advancement of exosome isolation techniques, the possibility of using biologically active molecules for renal injury prediction and diagnosis has emerged. The use of urinary exosomes in AKI and CKD diagnosis is based on changes in the expression of specific molecule cargos of exosomes. This review article summarizes the diagnosis and therapeutic applications of exosomes in AKI and CKD.

Salting-Out Approach Is Worthy of Comparison with Ultracentrifugation for Extracellular Vesicle Isolation from Tumor and Healthy Models

The role of extracellular vesicles (EVs) has been completely re-evaluated in the recent decades, and EVs are currently considered to be among the main players in intercellular communication. Beyond their functional aspects, there is strong interest in the development of faster and less expensive isolation protocols that are as reliable for post-isolation characterisations as already-established methods. Therefore, the identification of easy and accessible EV isolation techniques with a low price/performance ratio is of paramount importance. We isolated EVs from a wide spectrum of samples of biological and clinical interest by choosing two isolation techniques, based on their wide use and affordability: ultracentrifugation and salting-out. We collected EVs from human cancer and healthy cell culture media, yeast, bacteria and Drosophila culture media and human fluids (plasma, urine and saliva). The size distribution and concentration of EVs were measured by nanoparticle tracking analysis and dynamic light scattering, and protein depletion was measured by a colorimetric nanoplasmonic assay. Finally, the EVs were characterised by flow cytometry. Our results showed that the salting-out method had a good efficiency in EV separation and was more efficient in protein depletion than ultracentrifugation. Thus, salting-out may represent a good alternative to ultracentrifugation.

Pushing the Limits for Open Hole Zonal Isolation – Design and Qualification of Expandable Steel Packer

Enhancing gas productivity is linked to multistage stimulation (MSS). Choosing a cemented over uncemented solution is driven by factors such as operational efficiency, drilling practices, and isolation techniques. Swellable and mechanical packers have been used widely. A new packer type, an expandable steel packer, has been qualified recently, the expandable steel packer combines the strengths of mechanical and swellable packers and will provide an option for openhole completions. The 4.5-in. expandable steel packer design was optimized to meet most demanding applications with the following characteristics: reduced running outside diameter (OD) to 5.6 in., premium assembly technique by crimping, double sleeve pressure self-compensation, and use of nickel alloys for sour environment. After the design of the packer was completed, the 4.5-in. expandable steel packer was qualified according to the API Spec 19OH (API 2018) standard protocol at 15,000 psi with thermal variation between 320°F and 68°F. The packer was tested in a casing with inside diameter (ID) of 6.5 in. The test casing had an ID of 6.5 in. whereas nominal hole size ranges from 5.875 in. to 6.125 in. It was chosen to simulate a washout and considering the calculated maximum expansion ratio for the steel to verify the 15,000-psi pressure rating capability. The test casing was built with a heat exchanger, high-pressure pump, and pressure and temperature sensors. The packer was expanded inside the dummy well with all the measuring instruments in place. Expansion pressure signatures were observed as predicted. The analysis of the packer setting pressure curves showed expansion initiation and full casing ID contact. The liquid differential pressure test from each side of the packer proved the internal pressure compensation performed as expected. No leak was observed during the pressure steps of 15.000 psi held for 15 minutes while cycling the temperature from 320°F to 68°F and back to 320°F. The expandable steel packer utilizes a unique double-sleeve system for self-pressure compensation during ball-drop stimulation operations. The packer expandable sleeve is protected during deployment by the end fittings. Expandable steel packers exhibit robustness during running in hole, enable setting on demand, have a high expansion ratio, require no de-rating vs. hole size, and have low sensitivity to thermal variations.

A COMPARATIVE CLINICAL EVALUATION FOR PRECISE ISOLATION USING ADDITION SILICONE DAM COVERAGE WITH CONVENTIONAL ISOLATION TECHNIQUES- AN IN-VIVO STUDY

Context: A proper isolation technique plays a key role in the success of restoration of carious tooth. Aim Of The Study: The aim of this in-vivo study was to evaluate efficacy of addition silicone dam coverage technique with conventional isolation methods in restorative procedures and endodontic treatment. Settings And Design: Forty-Five patients who fulfill the inclusion criteria were selected for the study. Materials And Methods: All the participants underwent clinical procedures using 3 different isolation techniques. Group-1: Clinical procedures were carried out using traditional cotton roll isolation. Group-2: Clinical procedures were carried out using conventional rubber dam isolation procedure. Group-3: Clinical procedures were carried out using addition silicone dam coverage technique. The efficacy of isolation in terms of clinician usage and patient comfort is evaluated by a single evaluator. The results were tabulated and statistically analyzed. Statistical Analysis: IBM SPSS (version 21.0) software was used. Chi-square test was performed, considering P < 0.05 for statistical significance. Results: All the groups demonstrated satisfactory clinical performance. Upon inter and intra-group comparison of the isolation methods, there was statistically significant difference (P > 0.05). Conclusion: It is important to achieve an aseptic environment in clinical restorative and endodontic procedures. Addition silicone dam coverage technique is a chair side modified design which is user friendly with improved treatment efficacy. However, long-term clinical studies must be needed for further evaluation.

Cell Therapy: Types, Regulation, and Clinical Benefits

Cell therapy practices date back to the 19th century and continue to expand on investigational and investment grounds. Cell therapy includes stem cell- and non–stem cell-based, unicellular and multicellular therapies, with different immunophenotypic profiles, isolation techniques, mechanisms of action, and regulatory levels. Following the steps of their predecessor cell therapies that have become established or commercialized, investigational and premarket approval-exempt cell therapies continue to provide patients with promising therapeutic benefits in different disease areas. In this review article, we delineate the vast types of cell therapy, including stem cell-based and non–stem cell-based cell therapies, and create the first-in-literature compilation of the different “multicellular” therapies used in clinical settings. Besides providing the nuts and bolts of FDA policies regulating their use, we discuss the benefits of cell therapies reported in 3 therapeutic areas—regenerative medicine, immune diseases, and cancer. Finally, we contemplate the recent attention shift toward combined therapy approaches, highlighting the factors that render multicellular therapies a more attractive option than their unicellular counterparts.

Torsional Vibration Control of a Structure using Fluid Viscous Dampers

Damping plays a major role in design of structures resistant to earthquakes. The damping reduces the effective of the structure when they are assigned to lateral loads by energy dissipation. The number of dampers is available and in use today. Most of the dampers usually isolate the super structure from the substructure, dividing them in order to hamper the flow of vibrations into the superstructure. This classification is termed as base isolation techniques. While, the rest of the damping techniques, dissipates the oncoming vibrations on the superstructure itself and minimizes the damage to the superstructure. In this present study, Fluid Viscous Dampers (FVD) are used extensively over types of dampers. The structure endures two load types, the vertical loads and the sidewise loads, and conveys to the foundation. In order to have earthquake resistant structures, FVD have been used. In the present study, Dissymmetric Buildings are analyzed with and without Fluid Viscous Dampers. The software ETABS 2016 was used. Using Time history analysis in ETABS software, the RC building is considered and the structure is evaluated and connect with and without FVD.

FA Approach on MIM (Metal-Insulator-Metal) Capacitor Failures

MIM (Metal-Insulator-Metal) capacitor is a capacitor fabricated between metal layers and usually in an array form. Since it is usually buried within stack of back-end metal layers, neither front side nor backside FA fault isolation techniques can easily pinpoint the defect location of a failing MIM capacitor. A preliminary fault isolation (FI) often needs to be performed by biasing the desired failing state setup to highlight the difference(s) of FI site(s) between failing unit & reference. Then, a detailed study of the CAD (Computer Aided Design) schematic and die layout focusing on the difference(s) of FI site(s) will lead to a more in-depth analyses such as Focused Ion-Beam (FIB) circuit edit, micro-probing/nano-probing, Voltage Contrast (VC) and other available FA techniques to further identify the defective MIM capacitor. Once the defective MIM capacitor was identified, FIB cross-section or delayering can be performed to inspect the physical defect on the MIM capacitor. This paper presents the FA approach and challenges in successfully finding MIM capacitor failures.