Electrochemical determination of microRNAs based on isothermal strand-displacement polymerase reaction coupled with multienzyme functionalized magnetic micro-carriers

This study was supported by the National Natural Science Foundation of China (81371901), Doctoral Scientific Fund Project of the Ministry of Education of People's Republic of China (20134433110010), the Critical Point-of-Care Testing (CPOCT) Research grant of American Association for Clinical Chemistry (AACC) and 2015 Distinguished Academic Fellowships of Royal College of Engineering (DVF1415/2/79)

Sniffer dogs as a screening/diagnostic tool for COVID-19: a proof of concept study

Background: Sniffer dogs are able to detect certain chemical particles and are suggest to be capable of helping diagnose some medical conditions and complications, such as colorectal cancer, melanoma, bladder cancer, and even critical states such as hypoglycemia in diabetic patients. With the global spread of COVID-19 throughout the world and the need to have a real-time screening of the population, especially in crowded places, this study aimed to investigate the applicability of sniffer dogs to carry out such a task. Methods: Firstly, three male and female dogs from German shepherd (Saray), German black (Kuzhi) and Labrador (Marco) breeds had been intensively trained throughout the classical conditioning method for 7 weeks. They were introduced to human specimens obtained from the throat and pharyngeal secretions of participants who were already reported positive or negative for SARS-COV-2 infection be RT-PCR. Each dog underwent the conditioning process for almost 1000 times. In the meantime another similar condition process was conducted on clothes and masks of COVID-19 patient using another three male and female dogs from Labrador (Lexi), Border gypsy (Sami), and Golden retriever (Zhico) breeds. In verification test for the first three dogs, 80 pharyngeal secretion samples consisting of 26 positive and 54 negative samples from different medical centers who underwent RT-PCR test were in a single-blind method. In the second verification test for the other three dogs, masks and clothes of 50 RT-PCR positive and 70 RT-PCR negative cases from different medical center were used. Results: In verification test using pharyngeal secretion, the sniffer dogs� detection capability was associated with a 65 of sensitivity and 89 of specificity and they amanged to identify 17 out of the 26 positive and 48 out of the 54 true negative samples. In the next verification test using patients� face masks and clothes, 43 out of the 50 positive samples were correctly identified by the dogs. Moreover, out of the 70 negative samples, 65 samples were correctly found to be negative. The sensitivity of this test was as high as 86 and its specificity was 92.9. In addition, the positive and negative predictive values were 89.6 and 90.3, respectively. Conclusion: Dogs are capable of being trained to identify COVID-19 cases by sniffing their odour, so they can be used as a reliable tool in limited screening. © 2021, The Author(s)

Impact of Caffeine on Weight Changes Due to Ketotifen Administration

Purpose: Prescription of ketotifen as an effective antihistamine in asthma and allergic conditions is associated with side effect of weight gain. Caffeine is an agent which increases thermogenesis and improves energy expenditure and also effective in asthma. The aim of current study was to evaluate caffeine impact in reducing weight gain side effect of ketotifen. Methods: Male mice at the weight limit of 20-30 g in 8 groups were randomly chosen and injected following drug dosages for 45 days intraperitoneally: control group (normal saline 10 ml/kg), three groups of ketotifen (4, 8, 16 mg/kg), three groups of caffeine (4, 8, 16 mg/kg) and one group of ketotifen (4 mg/kg) in combination with caffeine (4 mg/kg). Weight changes have been recorded and assessed every 3 days for 45 days. Results: The results showed that in all dosages of the two drugs, significant weight loss occurred in comparison with the control group. Conclusion: The effect of caffeine on weight loss according to our results, matches with human studies, while ketotifen contradictory to our assumption, resulted in weight loss which probably was related to the difference in metabolic pathways in mice and humans, or maybe the used doses of ketotifen in this study were insufficient to reduce TNF-α production or influence in serotonin release and be effective on appetite or weight gain

Unique properties of core shell Ag@Au nanoparticles for the aptasensing of bacterial cells

In this article, it is shown that the efficiency of an electrochemical aptasensing device is influenced by the use of different nanoparticles (NPs) such as gold nanoparticles (Au), silver nanoparticles (Ag), hollow gold nanospheres (HGN), hollow silver nanospheres (HSN), silver–gold core shell (Ag@Au), gold–silver core shell (Au@Ag), and silver–gold alloy nanoparticles (Ag/Au). Among these nanomaterials, Ag@Au core shell NPs are advantageous for aptasensing applications because the core improves the physical properties and the shell provides chemical stability and biocompatibility for the immobilization of aptamers. Self-assembly of the NPs on a cysteamine film at the surface of a carbon paste electrode is followed by the immobilization of thiolated aptamers at these nanoframes. The nanostructured (Ag@Au) aptadevice for Escherichia coli as a target shows four times better performance in comparison to the response obtained at an aptamer modified planar gold electrode. A comparison with other (core shell) NPs is performed by cyclic voltammetry and differential pulse voltammetry. Also, the selectivity of the aptasensor is investigated using other kinds of bacteria. The synthesized NPs and the morphology of the modified electrode are characterized by UV-Vis absorption spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, and electrochemical impedance spectroscopy