Biodegradable and Non-Biodegradable Biomaterials and Their Effect on Cell Differentiation.

Biomaterials for tissue scaffolds are key components in modern tissue engineering and regenerative medicine. Targeted reconstructive therapies require a proper choice of biomaterial and an adequate choice of cells to be seeded on it. The introduction of stem cells, and the transdifferentiation procedures, into regenerative medicine opened a new era and created new challenges for modern biomaterials. They must not only fulfill the mechanical functions of a scaffold for implanted cells and represent the expected mechanical strength of the artificial tissue, but furthermore, they should also assure their survival and, if possible, affect their desired way of differentiation. This paper aims to review how modern biomaterials, including synthetic (i.e., polylactic acid, polyurethane, polyvinyl alcohol, polyethylene terephthalate, ceramics) and natural (i.e., silk fibroin, decellularized scaffolds), both non-biodegradable and biodegradable, could influence (tissue) stem cells fate, regulate and direct their differentiation into desired target somatic cells.

Reasons in Support of Data Security and Data Security Management as Two Independent Concepts: A New Model.

INTRODUCTION: Any information which is generated and saved needs to be protected against accidental or intentional losses and manipulations if it is to be used by the intended users in due time. As such, information managers have adopted numerous measures to achieve data security within data storage systems, along with the spread of information technology. BACKGROUND: The "data security models" presented thus far have unanimously highlighted the significance of data security management. For further clarification, the current study first introduces the "needs and improvement" cycle; the study will then present some independent definitions, together with a support umbrella, in an attempt to shed light on the data security management. FINDINGS: Data security focuses on three features or attributes known as integrity, identity of sender(s) and identity of receiver(s). Management in data security follows an endless evolutionary process, to keep up with new developments in information technology and communication. In this process management develops new characteristics with greater capabilities to achieve better data security. The characteristics, continuously increasing in number, with a special focus on control, are as follows: private zone, confidentiality, availability, non-repudiation, possession, accountability, authenticity, authentication and auditability. CONCLUSION: Data security management steadily progresses, resulting in more sophisticated features. The developments are in line with new developments in information and communication technology and novel advances in intrusion detection systems (IDS). Attention to differences between data security and data security management by international organizations such as the International Standard Organization (ISO), and International Telecommunication Union (ITU) is necessary if information quality is to be enhanced.

Reasons for deficiencies in health information laws in Iran.

INTRODUCTION: Laws, regulations, and guidelines are necessary external stimuli that influence the management of health data. They serve as external mechanisms for the reinforcement and quality improvement of health information. Despite their inevitable significance, such laws have not yet been sufficiently formulated in Iran. The current study explores reasons for inadequacies in the health information laws. METHODS: In this descriptive study, health-related laws and regulations from the United States, the United Kingdom, and Iran were first collected, using a review of the literature and available data. Then, bearing in mind the significant deficiencies in health information laws in Iran, the researchers asked a group of managers and policy makers in the healthcare field to complete a questionnaire to explore the reasons for such deficiencies. A test-retest method was used to determine the reliability of the questionnaire. Descriptive statistics and tables were then used to analyze the data. FINDINGS: Experts' opinion on reasons for deficiencies in health information laws and regulations in Iran are divided into four principal groups: cultural conditions of the community, the status of the health information system, characteristics of managers and policy makers in the healthcare field, and awareness level among public beneficiaries about laws. CONCLUSIONS: The health departments or ministries in developed countries have brought about suitable changes in their affiliated organizations by developing external data enhancement mechanisms such as information-related laws and standards, and accreditation of healthcare organizations. At the same time, healthcare organizations, under obligations imposed by the external forces, try to elevate the quality of information. Therefore, this study suggests that raising healthcare managers' awareness of the importance of passing health information laws, as an effective external mechanism, is essential.

A 10-year retrospective study on odontogenic tumors in Iran.

OBJECTIVE: The aim of this study was to review cases of odontogenic tumors diagnosed in two pathology centers in Tehran, Iran, during a 10-year period. STUDY DESIGN: Patients' records were seen at two teaching pathology Centre's of Shahid Beheshti University between the months of March 2000 to 2010 with histologic diagnosis of any type of odontogenic tumors. The records were analyzed for frequency, age, sex, site, as well as clinical, radiographic and histopathologic findings. RESULTS: Of 30706 biopsies, 4767 (15.5%) cases were diagnosed as oral and maxillofacial lesions. Among these, 720 cases were tumoral with 188 (26.1%) cases of odontogenic tumors. Tumors with odontogenic epithelium origin formed 70.2% of total numbers of odontogenic tumors. Mixed odontogenic tumors and tumors of odontogenic ectomesenchyme comprised 12.2% and 17.5% of the cases respectively. Ameloblastoma, with a frequency of 62.2% was the most common tumor in this review which was followed by odontoma and odontogenic myxoma. CONCLUSION: Although there are few studies on odontogenic tumors in literature, the comparison of our results with existing data shows significant differences in the distribution of tumors and age of patients, which may be due to ethnic features and geographic distribution of patients. Future studies on other ethnic groups are essential for further clarification of the findings in this research.

Cyclin d1 expression in odontogenic cysts.

OBJECTIVE: In the present study expression of cyclin D1 in the epithelial lining of odontogenic keratocyst, radicular cyst, dentigerous cyst and glandular odontogenic cyst was investigated to compare proliferative activity in these lesions. MATERIAL AND METHOD: Immunohistochemical staining of cyclin D1 on formalin-fixed, paraffin-embedded tissue sections of odontogenic keratocysts (n=23), dentigerous cysts (n=20), radicular cysts (n=20) and glandular odontogenic cysts (n=5) was performed by standard EnVision method. Then, slides were studied to evaluate the following parameters in epithelial lining of cysts: expression, expression pattern, staining intensity and localization of expression. RESULTS: The data analysis showed statistically significant difference in cyclin D1 expression in studied groups (p < 0.001). Assessment of staining intensity and staining pattern showed more strong intensity and focally pattern in odontogenic keratocysts, but difference was not statistically significant among groups respectively (p=0.204, 0.469). Considering expression localization, cyclin D1 positive cells in odontogenic keratocysts and dentigerous cysts were frequently confined in parabasal layer, different from radicular cysts and glandular odontogenic cysts. The difference was statistically significant (p < 0.01). CONCLUSION: Findings showed higher expression of cyclin D1 in parabasal layer of odontogenic keratocyst and the entire cystic epithelium of glandular odontogenic cysts comparing to dentigerous cysts and radicular cysts, implying the possible role of G1-S cell cycle phase disturbances in the aggressiveness of odontogenic keratocyst and glandular odontogenic cyst.

The effect of ghrelin on MK-801 induced memory impairment in rats.

Accumulating evidence indicates that the brain-gut peptide ghrelin which is expressed in hippocampus improves memory and learning processes. The MK-801, a noncompetitive NMDA receptor antagonist, has also shown amnesic properties in animal model. The current study was to find out whether intracerebroventricular administration of ghrelin can prevent amnesia induced by MK-801 in rats. A week after the surgery, during which cannuals were implanted in the lateral ventricular, the animals were trained and tested in a step-through type passive avoidance task. Memory retrieval was measured by step-through latency (STL) and total time in dark compartments (TDC). In the first series of experiments, we established a dose-response relationship for ghrelin on the passive avoidance paradigm. In the second set of experiments, animals were divided to two groups. In the first group, MK-801 (0.075, 0.15 and 0.3mg/kg) was injected intraperitoneally (i.p.) immediately after the acquisition session and in the second group MK-801 (same doses) was injected (i.p.) 30 min before the retention session. Analysis of data showed that in both groups, MK-801 impaired learning and memory. In the third set of experiments, administration of ghrelin (200 ng/rat) right after the acquisition session (i.e. before MK-801 injection) improved the MK-801 induced memory impairment, but administration of ghrelin before retrieval session did not affect the MK-801 induced memory impairment. These results show an interaction between ghrelin and glutamatergic system. A novel finding in this study is that ghrelin can prevent amnesia produced by NMDA antagonist in rats when injected in post-training phase.

The effect of in-service English education on medical professionals' language proficiency.

BACKGROUND: Despite its inevitable significance, the effect of in-service English education on medical professionals has rarely been studied longitudinally. The reason can be issues such as physicians' heavy workload, commuting problems, inappropriate class times, and inexperienced teaching staff. MATERIALS AND METHODS: A needs assessment worksheet was administered to faculty members of Shahid Beheshti University of Medical Sciences in Tehran and the responses were analyzed. A project for the promotion of faculty members' English proficiency was formulated. Then, following a placement test, 235 applicants from the university colleges and hospitals were classified into 28 homogeneous groups. After four terms of instruction, the participants' scores on the pre- and post- assessments were analyzed. RESULTS: There was significant improvement in participants' total scores on different communicative skills (P<0.001). Regarding individual skills also, they achieved meaningful gains on listening (P<0.001), writing (P = 0.038), and grammar (P<0.001), but failed to progress significantly on reading comprehension (P = 0.523). CONCLUSION: The administration of in-service education for skill-oriented courses, over a long period, can be quite encouraging and should be further strengthened. Regular instructions on each individual skill on the one hand and on their combination on the other are essential for success in such education.