The Homology Modeling and Docking Investigation of Human Cathepsin B

Background: Cathepsin B comprises a group of lysosomal cysteine proteases belonging to the Papain family; it has an intracellular function in the process of protein catabolism, antigen processing in the immune response, and Alzheimer’s disease. In cancers, cathepsin B interferes with autophagy and intracellular catabolism, and breaks down extracellular matrix, decreases protease inhibitors expression, and ultimately helps to accelerate metastasis, tumor malignancy, and reduce immune resistance. Methods: In this study, the 3D structure of cathepsin B was constructed using modeler and Iterative Threading ASSEmbly Refinement (I-TASSER), based on similarity to the crystallographic model of procathepsin B (1PBH). Then, the predicted cathepsin B model was evaluated using PROCHECK and PROSA for quality and reliability. Molecular studies suggested that the amino acids cysteine 108, histidine 189, and histidine 190 form the envelope of the active site of cathepsin B. The docking studies of cathepsin B was performed with protease inhibitors cystatin C, E-64 and leupeptin. Results: The lowest binding energy was related to the cathepsin B-E-64 complex. Accordingly, it was found that E64 interacts with the amino acid cysteine 108 of the active site of cathepsin B. Leupeptin made 2 hydrogen bonds with cathepsin B, but none with the active site of cathepsin amino acids. Cystatin C established a hydrogen bond with the arginine 18 of cathepsin B and made electrostatic bonds with aspartate 148 of cathepsin B. Conclusion: Therefore, the bioinformatics and docking studies of cathepsin B with its inhibitors could be used as reliable identification, treatment, and alternative methods for selecting the inhibitors and controllers of cancer progression

Epidemiologic study of fall-related head injury in Iran and its comparison with other countries: review article

Head injury is one of the most important types of injury and is responsible for most of the deaths due to trauma. Low-income and middle-income countries face with more risk factors, but they still lack adequate health-care capacity to deal with complications. Trauma literally means the damage and injury, and head injury was defined as physical damage to the brain or skull caused by external forces. Head trauma is an important event. Anyone can fall including toddlers, adults and elders. There are several mechanisms for head injury, including motor vehicle accidents, falls, assault and violence. After the motor vehicle accidents, fall is the second most important cause of head injury. Deaths from falling in countries with lower socioeconomic conditions are higher. To collect the information for this study, the PubMed, Scopus and Google Scholar databases were used. Sixty-four related articles were reviewed from 1980 to 2018. The keywords including "head injury", "head trauma", "brain damage", "fall mechanism", "Iran" and "epidemiology" were used to search the articles. According to the findings of this review fall is the second most common head injury mechanism in Iran. The fall mechanism is more common in the age group of young children and elderly. Also, the incidence of fall mechanism is more in males with head injury than women. In most other countries in the world, fall is the first and the second head injury mechanism. Also, falling from lower altitudes is a more common mechanism than a fall from higher altitude in injury to the head. Falling from lower level is a more common mechanism than fall from higher level in head injuries. In addition, the outbreak of the fall mechanism in children and the elderly with head injuries is more. Despite the efforts that have been made in the past years to determine the pattern of epidemiology of head trauma and its results in Iran, there is not enough information on fall-related head injury. Considering that the head traumatic injury is one of the most common and most dangerous outcomes of fall, the purpose of this review study is to investigate epidemiologic fall-related head injury