Platelet-rich fibrin (PRF) gel modified by a carbodiimide crosslinker for tissue regeneration

Platelet-rich fibrin (PRF) as a rich source of effective growth factors has been used as a scaffold in tissue regeneration. It is known that PRF exhibits rapid degradability against enzymes, which should be decreased using crosslinking agents to reduce the release rate of growth factors and increase the effectiveness of tissue regeneration. In this study, a carbodiimide crosslinker with different concentrations (0.01%, 0.05%, 1%, and 2%) was used to modify and improve the properties of PRF gel. The crosslinked gels were evaluated with analyses such as SEM, swelling, degradability, mechanical strength, release test, cytotoxicity, and cell adhesion. The results showed that with increasing crosslinker concentration, the morphology of the fiber structure changes drastically, the swelling rate decreases from 300% (control) to 160% for the crosslinked gel, the degradation time for the control sample increases from 8 days to more than two weeks for the crosslinked gel, and the Young''s modulus increases from 0.15 MPa (control) to 0.61 MPa for the crosslinked samples. Growth factors also showed lower release with increasing crosslinking ratio. Cytotoxicity assays demonstrated that by increasing the crosslinker concentration to 1% w/v, no cytotoxicity was observed. Cellular studies with DAPI staining showed that the cells penetrated well into the gels and were well distributed, especially in gels with lower crosslinker concentrations. In addition, the modified PRF gel can be used as a scaffold for tissue regeneration.

1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) as a crosslinker can improve the physical and mechanical properties of PRF gel by forming covalent bonds.     

Comparison of the accuracy of the London atlas and Smith method in dental age estimation in 5–15.99-year-old Iranians using the panoramic view

International Journal of Legal Medicine - Tooth development is widely used for age estimation and staging physical maturity. It is of great importance in dental age estimation in forensic...     

Disability and post-trauma stress in the population over 15 years old in Kashan, Iran: A population-based study

Purpose: One of the consequences of trauma-related injuries is disability. There are more than one billion people with disabilities worldwide. Disability in people reduces their quality of life. The goal of this study was to determine the rate of post-trauma stress and disability related to trauma in the population over 15 years old in Kashan during a solar year of 2018-2019. Methods: This is a cross-sectional population-based study. A cluster sampling method was used in the city of Kashan, and 3880 persons were interviewed with individuals randomly selected in each household. If a person had trauma during one year ago, the World Health Organization Disability Assessment Schedule 2.0 and Post Trauma Stress Disorder (PTSD) Checklist were applied for further interview. Data were analyzed using Chi-square test or t-test. Results: Among the 3880 participants residing in Kashan, 274 (7.1%) reported a history of traumatic injury during one year ago in 2018-2019. Incidence of all injuries was estimated to be 70.61 (62.60-78.70) per 1000 people. For the trauma population, 213 (77.7%) were male and 75.1% were married. About half of them (50.3%, 138/274) aged 21e39 years. The most common cause of injuries was related to traffic accidents: 140 (51.1%). Of the 274 trauma participants, 47 (17.2%) reported PTSD; 244 (89.1%) had a mild disability, and 30 (10.9%) reported moderate disability. Conclusion: One of the main causes of disability in the human community is the traumatic injuries. According to the results of this study, 89.1% of trauma participants have sustained at last mild disability following trauma. These people require follow-up and post-treatment support. It should be noted that psychological complications such as PTSD are as significant as physical symptoms.     

The effect of oxybutynin on cardiac autonomic modulation in healthy subjects

Purpose

The aim of this study was to assess the various doses of oral oxybutynin on cardiac autonomic modulation by measuring short-term heart rate variability (HRV) indexes during supine rest position.

Methods

Eight male healthy subjects (20–23 years) participated in the double-blind crossover randomized study. The single dose of oxybutynin (2.5, 5 and 10 mg) or placebo was given to the volunteers in four sessions within 5-day intervals. Before and minutes of 30, 60, 90 and 120 after administration, lead II electrocardiogram (ECG) was recorded for 5 min. ECG extracted RR intervals data became the base of the calculation of time domain and frequency domain HRV parameters, which indicate cardiac autonomic activity. Statistical analysis was done by using the nonparametric Wilcoxon and Kruskal–Wallis tests.

Results

The data analysis has revealed that MNN (P < 0.001), SDNN (P < 0.05), PNN50% (P < 0.01), RMSSD (P < 0.001), HFnu (P < 0.05) and LF/HF ratio (P < 0.05) values were significantly increased relative to baseline at various time points in all the groups except in placebo group. LFnu (P < 0.05) values were significantly increased relative to baseline at various time points in all the groups except in placebo group.

Conclusions

Our findings have revealed that acute consumption of 2.5, 5 and 10 mg oxybutynin (an anticholinergic compound) in the juvenile healthy male subjects produces a cholinergic effect according to time and frequency domain of HRV indexes.     

Expression of recombinant parvalbumin from wolf-herring fish and determination of its IgE-binding capability

In this study, we produced the recombinant form of parvalbumin from wolf-herring fish and determined its IgE reactivity. Parvalbumin cDNA was sub-cloned into pET28 and expressed in Escherichia coli BL-21. The immunoreactivities of the recombinant and native parvalbumins were compared, and the effect of calcium binding was determined by sera from 25 fish-allergic patients. ELISA and Western blotting confirmed similar IgE-reactivities of the recombinant and native proteins and confirmed that this phenomenon is highly dependent on calcium binding. The recombinant protein was 94.5% similar to carp parvalbumin (Cyp c1). Approximately 72% of patients reacted strongly with recombinant parvalbumin, 80% of them reacted with the native form and only 56% showed IgE reactivity with crude extract. Because the IgE-binding capacity of recombinant wolf-herring parvalbumin is retained and is highly similar to Cyp c1, the wild and hypoallergenic forms of this allergen could be used for diagnosis and immunotherapy of fish allergy, respectively.     

Oriented nanofibrous silk as a natural scaffold for ocular epithelial regeneration

The aim of this study was to develop nanofibrous silk substrates for limbal stem cell expansion that can serve as a potential alternative substrate to replace human amniotic membrane. The human limbal stem cell was used to evaluate the biocompatibility of substrates (random and oriented nanofibrous mats, and human amniotic membrane) based on their phenotypic profile, viability, proliferation, and attachment ability. Biocompatibility results indicated that all substrates were highly biocompatible, as limbal stem cells could favorably attach and proliferate on the nanofibrous surfaces. Microscopic figures showed that the human limbal stem cells were firmly anchored to the substrates and were able to retain a normal corneal stem cell phenotype. Microscopic analyses illustrated that cells infiltrated the nanofibers and successfully formed a three-dimensional corneal epithelium, which was viable for 15 days. Immunocytochemistry and real-time PCR results revealed no change in the expression profile of limbal stem cells grown on nanofibrous substrates when compared to those grown on human amniotic membrane. In addition, electrospun nanofibrous silk substrates especially oriented mat provides not only a milieu supporting limbal stem cells expansion, but also serve as a useful alternative carrier for ocular surface tissue engineering and could be used as an alternative substrate to amniotic membrane.     

Reinfection risk of novel coronavirus (COVID-19): A systematic ‎review of current evidence

BACKGROUNDThere is recently a concern regarding the reinfection and reactivation of previously reCoVered coronavirus disease 2019 (CoVID-19) patients.AIMTo summarize the recent findings and reports of CoVID-19 reinfection in patients previously reCoVered from the disease.METHODSThis study was a systematic review of current evidence conducted in August 2020. The authors studied the probable reinfection risk of novel coronavirus (CoVID-19). We performed a systematic search using the keywords in online databases. The investigation adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to ensure the reliability and validity of this study and results.RESULTSWe reviewed 31 studies. Eight studies described reCoVered patients with reinfection. Only one study reported reinfected patients who died. In 26 studies, there was no information about the status of the patients. Several studies indicated that reinfection is not probable and that post-infection immunity is at least temporary and short.CONCLUSIONBased on our review, we concluded that a positive polymerase chain reaction retest could be due to several reasons and should not always be considered as reinfection or reactivation of the disease. Most relevant studies in positive retest patients have shown relative and probably temporary immunity after the reCoVery of the disease.     

Evaluating mechanism and severity of injuries among trauma patients admitted to Sina Hospital, the National Trauma Registry of Iran

Purpose: Injuries are one of the leading causes of death and lead to a high social and financial burden. Injury patterns can vary significantly among different age groups and body regions. This study aimed to evaluate the relationship between mechanism of injury, patient comorbidities and severity of injuries. Methods: The study included trauma patients from July 2016 to June 2018, who were admitted to Sina Hospital, Tehran, Iran. The inclusion criteria were all injured patients who had at least one of the following: hospital length of stay more than 24 h, death in hospital, and transfer from the intensive care unit of another hospital. Data collection was performed using the National Trauma Registry of Iran minimum dataset. Results: The most common injury mechanism was road traffic injuries (49.0%), followed by falls (25.5%). The mean age of those who fell was significantly higher in comparison with other mechanisms (p < 0.001). Severe extremity injuries occurred more often in the fall group than in the vehicle collision group (69.0% vs. 43.5%, p < 0.001). Moreover, cases of severe multiple trauma were higher amongst vehicle collisions than injuries caused by falls (27.8% vs. 12.9%, p = 0.003). Conclusion: Comparing falls with motor vehicle collisions, patients who fell were older and sustained more extremity injuries. Patients injured by motor vehicle collision were more likely to have sustained multiple trauma than those presenting with falls. Recognition of the relationship between mechanisms and consequences of injuries may lead to more effective interventions.