The novel arthroscopic subscapular sling procedure grants better stability than an arthroscopic Bankart repair in a cadaveric study.

PURPOSE: This novel arthroscopic subscapular sling procedure stabilizes the shoulder using a semitendinosus graft to create a sling around the subscapular tendon, which provides both static and dynamic stability. The aim of the study was to evaluate the biomechanical stability of the subscapular sling procedure in human cadaveric shoulders. The hypothesis was that the sling offers an equal stabilizing effect and range of motion compared to an arthroscopic Bankart repair. METHODS: Sixteen shoulders were investigated using an industrial robot-based testing platform and four different conditions: the physiologically intact shoulder, after creating a Bankart lesion, after arthroscopic Bankart repair, and finally after applying the subscapular sling procedure using a semitendinosus tendon graft. Joint translation and external rotation were evaluated for each condition. RESULTS: The results show improved stability in the shoulders with the subscapular sling. The robot testing revealed a significant reduction in translation in anterior and anterior-inferior directions compared to the arthroscopic Bankart repair. None of the shoulders were dislocated by forced manual abduction and external rotation. No difficulties were encountered in performing the arthroscopic subscapular sling procedure. Thorough postoperative anatomical dissection showed no alterations to structures at risk. CONCLUSION: The biomechanical results show increased stability with the use of the subscapular sling method.

1α,25-dihydroxyvitamin D3 promotes osteogenic activity and downregulates proinflammatory cytokine expression in human periodontal ligament cells.

BACKGROUND AND OBJECTIVE: The aim of this study was to assess the impact of 1α,25-dihydroxyvitamin D3 (vitamin D3) on osteogenic and inflammatory properties of human periodontal ligament (PDL) cells and investigate underlying mechanisms. MATERIAL AND METHODS: Human PDL cells, obtained from four subjects, were stimulated with vitamin D3 for 4-48 h. The bone markers osteopontin and osteocalcin and proinflammatory cytokine/chemokine expression was determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Cytokine and chemokine expression was determined after stimulation with the inflammation promoter lipopolysaccharide (LPS) in the presence or absence of vitamin D3. Alkaline phosphatase activity was assessed using p-nitrophenylphosphate substrate. RESULTS: Treatment with 30 ng/mL of vitamin D3, corresponding to an optimal plasma concentration of vitamin D, for 24 h had no effect on PDL cell number and morphology but increased PDL cell osteopontin and osteocalcin mRNA expression by about 70 and 40%, respectively, and, moreover, treatment with vitamin D3 for 48 h enhanced PDL cell alkaline phosphatase activity by about two times showing that vitamin D3 exerts pro-osteogenic effects in human PDL cells. Stimulation with LPS (1 µg/mL) for 4 h increased PDL cell interleukin (IL)-6 cytokine and chemokine ligand 1 (CXCL1) chemokine mRNA expression several fold. The LPS-induced increase in IL-6 and CXCL1 transcripts was attenuated by vitamin D3 (30 ng/mL). Treatment with vitamin D3 (3-300 ng/mL) for 24 h reduced the LPS-evoked increase in PDL cell IL-6 protein by about 50%. Vitamin D3 (30 ng/mL) had no effect on LPS-induced IL-1ß and MCP-1 mRNA expression. CONCLUSIONS: Vitamin D3 promotes osteogenic differentiation but also downregulates inflammation promoter-induced IL-6 cytokine and CXCL1 chemokine expression in human PDL cells, suggesting that vitamin D3 both stimulates bone regeneration and antagonizes inflammation in human periodontal tissue.

Estrogen regulates DNA synthesis in human gingival epithelial cells displaying strong estrogen receptor ß immunoreactivity.

BACKGROUND AND OBJECTIVE: Estrogen acts via estrogen receptor (ER) α and ß. The expression pattern of ERs and their importance in gingival tissues are not fully understood. In this study, we investigate gingival ER expression and effects of estrogen on gingival epithelial cell proliferation. MATERIAL AND METHODS: Gingival biopsies were obtained from both healthy and diseased sites in three male and three female subjects. Expression of ERα and ß was determined by immunohistochemistry. Effects of 17ß-estradiol (E(2) ) on cell proliferation, monitored by measuring DNA synthesis, were studied in cultured human gingival epithelial HGEPp.05 cells. RESULTS: Estrogen receptor ß, but not ERα, immunoreactivity was demonstrated in nuclei of epithelial cells in all layers of the gingival epithelium, but also in cells of the lamina propria. No differences were observed between male and female subjects. The same pattern, i.e. high ERß expression but no ERα expression, was observed in both healthy and diseased sites within each individual. No differences in the intensity of the ERß immunoreactive signal and the number of ERß-positive nuclei were observed between healthy and diseased gingiva. Treatment with a physiological concentration of E(2) (10 nm) had no effect on DNA synthesis in ERß- and ERα-expressing HGEPp.05 cells. In contrast, E(2) at high concentrations (500 nm and 10 µm) reduced DNA synthesis by 60-70%. CONCLUSION: Human gingival epithelial cells display strong ERß but low ERα immunoreactivity both in vivo and in culture. Estrogen attenuates gingival epithelial cell DNA synthesis at high but not low concentrations, suggesting a concentration-dependent mechanism.

The human periodontal ligament cell: a fibroblast-like cell acting as an immune cell.

BACKGROUND: Periodontal ligament cells are fibroblast-like cells characterized by collagen production but also possessing some osteoblastic features. In the light of numerous studies presented during recent times, which show that human periodontal ligament cells also produce cytokines and chemokines in response to inflammation promoters, it is reasonable to suggest that periodontal ligament cells play a role as promoters of periodontal inflammation through these mechanisms. MATERIAL AND METHODS: The periodontal ligament, which harbours the periodontal ligament cells, is a part of the attachment apparatus comprised of periodontal ligament cells, extracellular matrix and fibres, attaching the root cement to the alveolar bone. Periodontal ligament cells are in close proximity to bacteria within the plaque and the pocket, and thus these cells are readily accessible to bacterial endotoxins and other promoters of inflammation. RESULTS: Cytokines and chemokines, released by periodontal ligament cells upon stimulation with inflammation promoters, reach the blood vessels easily thanks to rich vascularization of the periodontium stimulating recruitment of white blood cells to the site of inflammation. In addition to classical inflammatory cells, such as leucocytes, macrophages and mast cells, the periodontal ligament cells also contribute to periodontal inflammation via their production and release of cytokines and chemokines. CONCLUSION: Therefore, pharmacological treatment of periodontitis should aim to reduce the release of proinflammatory agents not only from classical inflammatory cells but also from periodontal ligament cells.

Differential regulation of chemokine expression by estrogen in human periodontal ligament cells.

BACKGROUND AND OBJECTIVE: Estrogen modulates inflammatory responses, but the mechanisms involved have not yet been identified. Periodontal ligament (PDL) cells produce chemokines (a group of chemoattractant molecules that recruit leukocytes) and it has been suggested that estrogen modulates periodontal inflammation by regulating the expression of chemokines by PDL cells. Therefore, the objectives of this study were to investigate the regulation of chemokine ligand 2 [CCL2/monocyte chemoattractant protein 1 (MCP-1)], chemokine ligand 3 [CCL3/macrophage inflammatory protein-1α (MIP-1α)] and chemokine ligand 5 (CCL5/RANTES) by estrogen in human PDL cells. MATERIAL AND METHODS: PDL cells were obtained from the PDL of premolars, extracted for orthodontic reasons, from two boys and two girls (16 and 17 years of age). PDL cell CCL2, CCL3 and CCL5 mRNA transcripts were determined by quantitative real-time PCR. The concentrations of CCL2, CCL3 and CCL5 proteins were determined by ELISAs. RESULTS: Treatment with 0.5 µg/mL of lipopolysaccharide (LPS, from Escherichia coli) + 100 nm 17ß-estradiol (E(2) ) for 24 h reduced the expression of CCL3 mRNA by about 40% compared to PDL cells treated with LPS alone. Attenuation of CCL3 mRNA was not associated with a decrease in CCL3 protein within 48 h, suggesting a slow turnover of the CCL3 protein. Interindividual differences in the effects of E(2) on CCL5 mRNA expression were observed. E(2) (100 nm) increased the expression of CCL5 by 40-60% in PDL cells derived from two subjects but reduced the expression of CCL5 by about 30% in cells from another subject. CCL2 mRNA and CCL2 protein were highly expressed, but not regulated by E(2) . Similar data were observed in cells obtained from both boys and girls. CONCLUSION: Regulation, by estrogen, of chemokine expression in PDL cells shows a complex pattern involving the down-regulation as well as the up-regulation of chemokines, suggesting that estrogen exerts both anti-inflammatory and proinflammatory effects through these mechanisms.

Computer-mediated instructional video: a randomised controlled trial comparing a sequential and a segmented instructional video in surgical hand wash.

BACKGROUND: Video-based instructions for clinical procedures have been used frequently during the preceding decades. AIM: To investigate in a randomised controlled trial the learning effectiveness of fragmented videos vs. the complete sequential video and to analyse the attitudes of the user towards video as a learning aid. MATERIALS AND METHODS: An instructional video on surgical hand wash was produced. The video was available in two different forms in two separate web pages: one as a sequential video and one fragmented into eight short clips. Twenty-eight dental students in the second semester were randomised into an experimental (n = 15) and a control group (n = 13). The experimental group used the fragmented form of the video and the control group watched the complete one. The use of the videos was logged and the students were video taped whilst undertaking a test hand wash. The videos were analysed systematically and blindly by two independent clinicians. The students also performed a written test concerning learning outcome from the videos as well as they answered an attitude questionnaire. RESULTS: The students in the experimental group watched the video significantly longer than the control group. There were no significant differences between the groups with regard to the ratings and scores when performing the hand wash. The experimental group had significantly better results in the written test compared with those of the control group. There was no significant difference between the groups with regard to attitudes towards the use of video for learning, as measured by the Visual Analogue Scales. Most students in both groups expressed satisfaction with the use of video for learning. CONCLUSION: The students demonstrated positive attitudes and acceptable learning outcome from viewing CAL videos as a part of their pre-clinical training. Videos that are part of computer-based learning settings would ideally be presented to the students both as a segmented and as a whole video to give the students the option to choose the form of video which suits the individual student's learning style.

Simulation of patient encounters using a virtual patient in periodontology instruction of dental students: design, usability, and learning effect in history-taking skills.

Simulations are important educational tools in the development of health care competence. This study describes a virtual learning environment (VLE) for diagnosis and treatment planning in oral health care. The VLE is a web-based, database application where the learner uses free text communication on the screen to interact with patient data. The VLE contains forms for history taking, clinical images, clinical data and X-rays. After reviewing the patient information, the student proposes therapy and makes prognostic evaluations of the case in free text. A usability test of the application was performed with seven dental students. The usability test showed that the software responded with correct answers to the majority of the free text questions. The application is generic in its basic functions and can be adapted to other dental or medical subject areas. A randomised controlled trial was carried out with 39 students who attended instruction in history taking with problem-based learning cases, lectures and seminars. In addition, 16 of the 39 students were randomly chosen to practise history taking using the virtual patient prior to their first patient encounter. The performance of each student was recorded on video during the patient sessions. The type and order of the questions asked by the student and the degree of empathy displayed towards the patient were analysed systematically on the videos. The data indicate that students who also undertook history taking with a virtual patient asked more relevant questions, spent more time on patient issues, and performed a more complete history interview compared with students who had only undergone standard teaching. The students who had worked with the virtual patient also seemed to have more empathy for the patients than the students who had not. The practising of history taking with a virtual patient appears to improve the capability of dental students to take a relevant oral health history.

Organic solvent encephalopathy: an old hazard revisited.

This report describes neurologic and respiratory symptoms among 26 engineers and contract laborers who used organic solvents and detergents to remove polychlorinated biphenyl contamination from a poorly ventilated factory basement. Neurologic symptoms included persistent central nervous system deficits; these developed in one worker after only 3 days. Respiratory symptoms included cough that persisted for more than 2 years. Laborers were more likely to report symptoms than were engineers. Appropriate ventilation or respirator use might have prevented the workers' morbidity. This incident serves as a reminder that organic solvent-related occupational illness continues to occur despite worker-health regulations and knowledge of preventive measures.