The novel coronavirus, known as 2019-nCoV or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused an epidemic with high mortality and morbidity since December 2019, in Wuhan, China. The infection has now been transmitted to more than 210 countries worldwide and caused more than 200,000 deaths. Similar to other coronaviruses such as Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV), SARS-CoV-2 appears to less commonly affect pediatrics and to cause less severe disease along with fewer symptoms compared to adults. Available data suggest that the pediatric population is just as likely as adults to become infected with SARS-CoV-2. However, they may be asymptotic or have milder symptoms than adults; they can be potential carriers of the disease. This article reviews the present understanding of SARS-CoV-2 infection in the pediatric age group in comparison with MERS-CoV and SARS-CoV.

Purpose Organoids are three-dimensional cultures of stem cells in an environment similar to the body’s extracellular matrix. This is also a novel development in the realm of regenerative medicine. Stem cells can begin to develop into 3D structures by modifying signaling pathways. To form organoids, stem cells are transplanted into the extracellular matrix. Organoids have provided the required technologies to reproduce human tissues. As a result, it might be used in place of animal models in scientific study. The key goals of these investigations are research into viral and genetic illnesses, malignancies, and extracellular vesicles, pharmaceutical discovery, and organ transplantation. Organoids can help pave the road for precision medicine through genetic editing, pharmaceutical development, and cell therapy. Methods PubMed, Google Scholar, and Scopus were used to search for all relevant papers written in English (1907–2021). The study abstracts were scrutinized. Studies on the use of stem-cell-derived organoids in regenerative medicine, organoids as 3D culture models for EVs analysis, and organoids for precision medicine were included. Articles with other irrelevant aims, meetings, letters, commentaries, congress and conference abstracts, and articles with no available full texts were excluded. Results According to the included studies, organoids have various origins, types, and applications in regenerative and precision medicine, as well as an important role in studying extracellular vesicles. Conclusion Organoids are considered a bridge that connects preclinical studies to clinical ones. However, the lack of a standardized protocol and other barriers addressed in this review, hinder the vast use of this technology. Lay Summary Organoids are 3D stem cell propagations in biological or synthetic scaffolds that mimic ECM to allow intercellular or matrix-cellular crosstalk. Because these structures are similar to organs in the body, they can be used as research models. Organoids are medicine’s future hope for organ transplantation, tumor biobank formation, and the development of precision medicine. Organoid models can be used to study cell-to-cell interactions as well as effective factors like inflammation and aging. Bioengineering technologies are also used to define the size, shape, and composition of organoids before transforming them into precise structures. Finally, the importance of organoid applications in regenerative medicine has opened a new window for a better understanding of biological research, as discussed in this study.

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Amyotrophic lateral sclerosis is a pernicious neurodegenerative disorder that is associated with the progressive degeneration of motor neurons, the disruption of impulse transmission from motor neurons to muscle cells, and the development of mobility impairments. Clinically, muscle paralysis can spread to other parts of the body. Hence it may have adverse effects on swallowing, speaking, and even breathing, which serves as major problems facing these patients. According to the available evidence, no definite treatment has been found for amyotrophic lateral sclerosis (ALS) that results in a significant outcome, although some pharmacological and non-pharmacological treatments are currently applied that are accompanied by some positive effects. In other words, available therapies are only used to relieve symptoms without any significant treatment effects that highlight the importance of seeking more novel therapies. Unfortunately, the process of discovering new drugs with high therapeutic potential for ALS treatment is fraught with challenges. The lack of a broad view of the disease process from early to late-stage and insufficiency of preclinical studies for providing validated results prior to conducting clinical trials are other reasons for the ALS drug discovery failure. However, increasing the combined application of different fields of regenerative medicine, especially tissue engineering and stem cell therapy can be considered as a step forward to develop more novel technologies. For instance, organ on a chip is one of these technologies that can provide a platform to promote a comprehensive understanding of neuromuscular junction biology and screen candidate drugs for ALS in combination with pluripotent stem cells (PSCs). The structure of this technology is based on the use of essential components such as iPSC- derived motor neurons and iPSC-derived skeletal muscle cells on a single miniaturized chip for ALS modeling. Accordingly, an organ on a chip not only can mimic ALS complexities but also can be considered as a more cost-effective and time-saving disease modeling platform in comparison with others. Hence, it can be concluded that lab on a chip can make a major contribution as a biomimetic micro-physiological system in the treatment of neurodegenerative disorders such as ALS.

Background: The right heart thrombus (RHT) embolizes from deep venous thrombi and sits in the right atrium or the right ventricle. We aimed to determine the occurrence and prognosis of the RHT in patients with pulmonary embolism. Methods: We reviewed the cohort data of 622 patients with acute pulmonary embolism obtained from the registry of Tehran Heart Center. Demographic, physiological, clinical, and echocardiographic data, as well as clinical outcomes, were compared between patients with and without the RHT. Results: The study population comprised 622 patients, including 329 men (52.8%). The mean age of the patients was 60.2±17.0 years. Thirty patients (4.8%) had echocardiographically proven RHT. Baseline demographic and clinical characteristics were not different between the 2 groups. Right ventricular dysfunction was more prevalent in the RHT (+) group, and more patients in this group were treated with thrombolysis (P=0.013 and P<0.001, respectively). Overall, 3 out of 21 patients (14.2%) in the RHT (+) group vs 29 out of 306 patients (9.4%) in the RHT (−) group died at 1 month (P=0.445) and 5 out of 21 patients (23.8%) in the RHT (+) group vs 56 out of 307 patients (18.2%) in the RHT (−) group died at 1 year (P=0.562). Conclusion: The RHT is an influential complication in patients with pulmonary emboli, and it seems to increase the mortality rate of patients with acute pulmonary embolism.

To determine and compare ocular characteristics and refractive errors between major thalassemia patients and normal subjects. In this study, 71 thalassemia major patients and 79 age and sex-matched healthy subjects that were selected in an ongoing manner underwent complete optometric and ophthalmic examinations, including autorefraction, subjective refraction, fluorescein tear break-up time, and pachymetry after anthropometric measurements. The results showed that the mean UCVA was better in the control group versus the thalassemia group (P<0.001), while there was no difference in BCVA between the two groups (P=0.416). Moreover, the mean spherical equivalent was 0.38±0.13 D less in the thalassemia group compared to the control group (P=0.007), while corneal power (P<0.001) and cylinder power (P=0.001) were larger in thalassemia patients. The most common type of astigmatism was against the rule pattern in thalassemia patients and with the rule pattern in the control group (P<0.001). The mean tear break-up time was 11.35±6.43 in the thalassemia group and 14.63±5.79 in the control group (P=0.001), and the mean near the point of accommodation (NPA) (P=0.009) and near the point of convergence (NPC). (P=0.003) were significantly smaller in the thalassemia group compared to the control group. These patients suffer from a myopic shift due to exaggerated responses to changes in ocular growth, dry eye secondary to goblet cell loss, and a higher prevalence of vertical astigmatism due to eyelid laxity and pressure on the cornea. Therefore, regular ophthalmological evaluations are highly recommended in these patients.

&aragangliomas are tumors that may located within intra or extra-adrenal regions .The histologic pattern of paragangliomas known as Zellbellen pattern consists of cell nests that are cinctured with fibro vascular tissue. The exact cause of formation of carotid body tumors has not been recognized but according to the higher incidence of these tumors in high altitude areas it seems that hypoxia may have a role in activating the chemoreceptors and also tumor organization. Another cause of chronic hypoxia is chronic obstructive pulmonary disease which may relate to carotid body tumor. Although the various diagnostic methods, the diagnosis is delayed because the most numbers of these tumors are asymptomatic. Material and Method PIntroduction: Carotid body tumors are rare tumors of the head and neck that arise from a chemical receptor organ with unknown underlying cause. But it seems that living at high altitudes can increase the incidence of these tumors. Materials and Methods:This research was the result of a study on a series of recorded cases of carotid body tumors. Recorded data from 100 patients with carotid body tumors were collected between 2014 and 2016. Data analysis was performed in SPSS software and quality and percentage data were reported for quality data and mean and standard deviation for quantitative data.Results: In this study, the mean age of the total affected population (24 12.24) was 51.74. The prevalence of carotid body tumors was higher in women than men (78% vs. 22%). Also, carotid body tumors were mostly unilateral (90% vs. 10%) and the frequency of tumors on the right was higher than on the left (51% vs. 37%). All patients in our study underwent surgical resection and the overall survival was 100%. Conclusion:Carotid body tumors are rare and almost asymptomatic tumors in the head and neck that are mainly seen in non-smokers with a mean age of 51 years. Surgery is one of the treatment options for these tumors. But radiotherapy may also be used as an alternative method.