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.

The function of fibroblast cells in wounded areas results in reconstruction of the extra cellular matrix and consequently resolution of granulation tissue. It is suggested that the use of platelet-rich plasma can accelerate the healing process in nonhealing or slow-healing wounds. In this study, a simple and novel method has been used to fabricate an electrospun three-layered scaffold containing plasma rich in growth factor with the aim of increasing the proliferation and migration of fibroblast cells in vitro. First, plasma rich in growth factor was derived from platelet rich plasma, and then a three-layered scaffold was fabricated using PLLA nanofibers as the outer layers and plasma rich in growth factor-containing gelatin fibers as the internal layer. The growth morphology of cells seeded on this scaffold was compared to those seeded on one layered PLLA scaffold. The study of the cell growth rate on different substrates and the migration of cells in response to the drug release of multilayered scaffold was investigated by the cell quantification assay and a modified under agarose assay. Scanning electron microscopy and fluorescence images showed that cells seeded on multilayered scaffold were completely oriented 72 hours after seeding compared to those seeded on PLLA scaffold. The cell quantification assay also indicated significant increase in proliferation rate of cells seeded on three-layered scaffold compared to those seeded on PLLA scaffold and finally, monitoring cell migration proved that cells migrate significantly toward the three-layered scaffold up to 48 to 72 hours and afterwards start to show a diminished migration rate toward this scaffold. K E Y W O R D S electrospinning, fibroblast migration, multilayered scaffolds, platelet rich plasma, skin tissue engineering

Inflammatory bowel disease (IBD) is a group of inflammatory disorders mainly affecting the colon and small intestine. The main types of IBD are Crohn's disease (CD) and ulcerative colitis (UC). UC is restricted to the large intestine whereas CD can affect any part of the gastrointestinal tract. Treating this disorder depends on the form and level of severity. Common treatment involves an anti-inflammatory drug, such as mesalazine, and an immunosuppressant, such as prednisone. Several signaling pathways, including nuclear factor (NF)-κB and nitric oxide (NO), and genetic and environmental factors are believed to play an important role in IBD. Amitriptyline is a commonly used antidepressant with known anti-inflammatory activities. Amitriptyline also acts on the NF-κB/NO pathway or cytokine production. Therefore, we hypothesize that antidepressants like amitriptyline can be pioneered and considered effective as an innovative and effective therapeutic in the treatment and attenuation of development of IBD in adjusted doses.

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Background: Sniffer dogs have been shown to detect certain chemical particles and to help diagnose many diseases and complications, such as colorectal cancer, melanoma, bladder cancer, and even dangerous states such as hypoglycemia in DM-1 patients. With the 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 these sniffer dogs.Methods: This study was done in two phases. In the first step, three dogs (including one German shepherd, one German black, one Labrador) were intensively trained by the classical conditioning method for seven weeks. Human specimens were obtained from the throat culture and pharyngeal secretions of both definitely positive and negative COVID-19 participants. During the first seven weeks, each dog underwent the conditioning process for averagely 1000 times. In the verification process, 80 pharyngeal secretion samples consisting of 26 positive samples of hospitalized patients and 54 negative samples of hospitalized patients for other medical reasons were provided to the training team in a single-blind manner. The verification test was done using three dogs (Lexi, Sami, and Kozhi). Another similar conditioning process was done using COVID-19 patients’ clothes and masks and the verification test was done using 50 positive and 70 negative samples by three other trained dogs (one Labrador, one Border gypsy, and one Golden retriever). Results: In the pharyngeal secretions verification test, the sniffer dogs showed 65% sensitivity and 89% specificity. In this process, they could identify 17 out of the 26 true positive samples and 48 out of the 54 true negative samples. According to the results, the positive predictive value and negative predictive value for this experiment were 74% and 84%, respectively. In the next verification test for the 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 by the canines. The sensitivity of this method 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 as the identifier of people with COVID-19 by detecting their odor and can be used as a reliable tool in limited screening.