Ultraviolet-induced Surface Grafting of Octafluoropentyl Methacrylate on Polyether Ether Ketone for Inducing Antibiofilm Properties

Since octafluoropentyl methacrylate is an antifouling polymer, surface modification of polyether ether ketone with octafluoropentyl methacrylate is a practical approach to obtaining anti-biofilm biocompatible devices. In the current study, the surface treatment of polyether ether ketone by the use of ultraviolet irradiation, so as to graft (octafluoropentyl methacrylate) polymer chains, was initially implemented and then investigated. The Fourier-transform infrared and nuclear magnetic resonance spectra corroborated the appearance of new signals associated with the fluoroacrylate group. Thermogravimetric curves indicated enhanced asymmetry in the polymer structure due to the introduction of the said new groups. Measuring the peak area in differential scanning calorimetry experiments also showed additional bond formation. Static water contact angle measurements indicated a change in wettability to the more hydrophobic surface. The polyether ether ketone–octafluoropentyl methacrylate surface greatly reduced the protein adsorption. This efficient method can modulate and tune the surface properties of polyether ether ketone according to specific applications

Effectiveness of Educational Intervention with non-wax and Virtual Typodont Methods in Practical Orthodontic course of Dental Students, Shahid Beheshti University of Medical Sciences

Objectives Considering the educational value of non-wax and virtual typodonts, in this study, the results of the evaluation were compared to quantify each of the indicators in the evaluation of knowledge, attitude, and performance. Methods All tenth-semester dental students were divided into 2 equal groups of 25 and were trained by two typodontists. A standard questionnaire with a Cronbach α of .830 was used to evaluate their knowledge and attitude, which was prepared based on a 7-point Likert scale. To analyze the data, the paired t test, independent t test, and analysis of covariance (ANOVA) were used with SPSS version 21. The significance level was set as 0.05. Results In each of the 2 educational methods, a significant increase in the overall score of the questionnaire completed by the students was observed after the educational intervention (P < 0.001).  Among the 17 questions related to students, only 1 question in the non-wax typodont group and 4 in the virtual typodont group did not show a significant effect of the intervention (P > 0.05). Conclusion Both typodonts had remarkable educational advantages and accounted for a large share of the points in the questionnaires. In cases where physical sense was important in education, non-wax typodont and in cases where spatial understanding of biomechanics was necessary in tooth movement, virtual typodont was superior

Mechanical Properties of 3D Printed Reinforced Polycaprolactone Composite Scaffolds

Objectives This paper describes the fabrication of a new porous 3D-printed scaffold composed of polycaprolactone (PCL) and polyether-ether ketone (PEEK) micro-particles for bone tissue engineering (BTE) applications. Methods In order to improve the compatibility of the reinforcing PEEK powder with polycaprolactone, the PEEK powder was surface-modified by an amino-silane coupling agent. After modification, Fourier-transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC) were used to investigate the chemical reaction between PEEK and silane coupling agent. In order to increase the compressive modulus of the 3D printed PCL scaffold, 10% silane-modified PEEK was incorporated into the PCL polymeric matrix. Scanning electron microscopy (SEM) was used for cell morphology and attachment evaluation. Results The results indicated that the silane coupling agent was successfully grafted onto the particle surface. The compressive modulus of PCL scaffold increased by incorporating the silane-modified PEEK, despite having higher porosity, compared with the pure PCL scaffolds. Addition of amino-silane had a positive impact on cell response, and that surface modification led to improved particle dispersion. Conclusion In conclusion, it seems that the incorporation of surface-modified PEEK micro-particles into the PCL porous scaffold could enhance its mechanical properties, and may be applicable for the management of large bone defects

Comparative effectiveness of Low Level Laser therapy and Transcutaneous Electric Nerve Stimulation on Temporomandibular Joint Disorders

Background: Temporomandibular joint disorders are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on temporomandibular joint disorders. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), sham-TENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure ANOVA and Boneferronie statistical tests. A p-value < 0.05 was considered significant. Results: The decrease in pain (p = 0.000), tenderness (p = 0.000) and increase in mouth-opening ability (p = 0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (p = 0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (p = 0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less importan

Involvement of neuronal pathways in the protective effects of hindlimb perconditioning during renal ischemia

Remote ischemic perconditioning (RPEC) is a therapeutic intervention that has been demonstrated to reduce renal ischemia/reperfusion (I/R) injury. However, the underlying renal protective mechanism remains unclear. The present study hypothesized that RPEC may utilize neural pathways to transfer the protective signal from the perconditioned hindlimb to the kidney. Following a right nephrectomy, rats were randomly allocated into five groups (n=6). The sham group underwent the surgical protocol only. In all other groups, the left renal pedicle was clamped for 45 min and reperfused for 24 h. The I/R control group then underwent 45 min ischemia and 24 h reperfusion (I/R) with no more intervention but the I/R‑NR control group underwent the ischemia and reperfusion followed by left femoral nerve (FN) and sciatic nerve (SN) resection. The RPEC group underwent ischemia and reperfusion followed by four cycles of 5 min occlusions of the left femoral artery and 5 min reperfusion. Finally, the RPEC‑NR group underwent ischemia and reperfusion followed by left FN and SN resection. Following 24 h, renal functional indices, plasma blood urea nitrogen (BUN) and creatinine (Cr) levels, urinary N‑acetyl‑β‑glucosaminidase (NAG) release and histopathological changes were assessed. Compared with the sham group, ischemia and reperfusion in the sham and I/R control groups resulted in renal dysfunction, indicated by significantly increased levels of BUN and Cr. This was accompanied by increased urinary NAG activity and morphological damage observed in control groups. In the RPEC group, renal histology and function were significantly improved compared with the control groups. However, FN and SN resection eliminated the protection of the kidney, which was induced by RPEC. In conclusion, remote hindlimb ischemic perconditioning reduced renal I/R injury in the rat kidney in a manner that potentially involves a neural pathway

The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption

Introduction: Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE.Methods: A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey’s Test and Analysis of Variance (ANOVA).Results: All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to 25±1.8 weeks in control group. The data analysis showed that in patients with DTE, laser intervention significantly accelerated tooth eruption (P < 0.05).Conclusion: Laser-assisted surgical removal of the fibrous tissue over erupting premolars (DTE) with appropriate irradiation parameters appears to be a promising adjunct to orthodontic treatment for bringing the premolar to the aligned and leveled dental arch

Protective effects of hydrogen sulfide on chronic kidney disease by reducing oxidative stress, inflammation and apoptosis

The current study aimed to examine the renoprotective effects of long-term treatment with sodium hydrosulfide (NaHS), a prominent hydrogen sulfide donor, in 5/6 nephrectomy animal model. Twenty-four rats were randomly divided into 3 groups including sham-operated group (Sham), 5/6-nephrectomized group (5/6 Nx), and NaHStreated group (5/6Nx+NaHS). NaHS (30 micromol/l) was added twice daily into the drinking water and renal failure was induced by 5/6 nephrectomy. Twelve weeks after surgical procedure, blood pressure, creatinine clearance (CCr), urine concentration of neutrophil gelatinase associated lipocalin (NGAL) and tissue concentration of malondialdehyde (MDA), superoxide dismutase (SOD), as well as renal morphological changes, apoptosis (cleaved caspase-3) and inflammation (p-NF-κB) were measured. Five-sixth nephrectomy induced severe renal damage as indicated by renal dysfunction, hypertension and significant histopathological injury which were associated with increased NGAL and MDA levels, oxidant/antioxidant imbalance, decreased SOD activity and CCr and also overexpression of p-NF-κB and cleaved caspase-3 proteins. Instead, NaHS treatment attenuated renal dysfunction through reduction of NGAL concentration, hypertension, CCr, oxidant/antioxidant imbalance, inflammation and apoptosis. These findings suggest that long term NaHS treatment can be useful in preventing the progression of CKD by improving oxidant/antioxidant balance and reducing inflammation and apoptosis in the kidney

Safety assessment of rice bran oil in a chicken embryo model

Objective: Rice Bran Oil (RBO) is extracted from the outer layer of rice. Little information is available regarding its safety. The present study was conducted to assess its safety in chicken embryo model. Materials and Methods: RBO was injected on day 4 of incubation of chickens. The tissues and serum samples were collected. Oxidative stress parameters in the liver, kidney and brain and biochemical parameters of serum were measured. The deformities were also investigated.  Results: The changes in the liver enzymes activity were not statistically significant. There was significant decrease and increase in lipid peroxidation and glutathione level, respectively. It is suggested that RBO is a natural antioxidant source. Low-density lipoprotein cholesterol (LDL) also decreased. No abnormal findings were observed in the chickens. Conclusion: No toxic effect was observed following RBO administration in chicken embryos. This study showed that RBO is not a safety concern

Angiotensin II of paraventricular nucleus is exaggerated the renal ischemia-reperfusion injury

Background: The renal sympathetic nerve activity (RSNA) is enhanced in renal failure. Paraventricular nucleus in hypothalamus is an important central site to regulate sympathetic activity. There are angiotensin II (Ang) II receptors in this nucleus. The aim of this study was to evaluate the effects of angiotensin II in hypothalamic paraventricular nucleus (PVN) on renal ischemia-reperfusion injury and RSNA. Methods: This study was done at 2013 in Physiology department of Tehran University of Medical Sciences. One week before the induction of renal Ischemia-Reperfusion (IR) in Sprague-Dawley rats, a cannula was inserted into the right PVN for microinjection of different doses of Ang II (3, 30, and 300 ng). Then right nephrectomy was done. After one week recovery, renal IR injury was induced by clamping the left renal artery for 45 minute and then reperfusion for 3 or 24 hour. Ten minutes before the induction of renal ischemia-reperfusion, administration of different doses of angiotensin II were done in different groups. In all animals, left renal sympathetic activity was recorded before and during renal ischemia. After 3 or 24 hours reperfusion the blood, kidney and brain were collected to assay renal function and histology and oxidative stress indices Superoxide Dismutase, SOD and Malondialdehyde, MDA) in PVN. Results: Administration of different pharmacological doses of angiotensin II into PVN exaggerated the renal IR injury. Angiotensin II in different doses increased the plasma creatinine and BUN levels and renal histological markers in comparison to renal IR in-jury (P<0.05). Angiotensin II had detrimental effects on RSNA and oxidative stress in-dices Super Oxide Dismutase (SOD) and Malondialdehyde (MDA) in PVN as the dose was increased (P<0.05). Conclusion: These data showed that the PVN is a responsive site for central Ang II-induced damage in renal IR injury. We suggested the central effects of Ang II in the PVN on renal IR injury are mediated by oxidative stress in the PVN, and the peripheral effects by a sympathetic pathway

Assessment of Dose Delivery to Supraclavicular and Axillary Lymph Nodes in Adjuvant Breast Cancer Radiotherapy, with or without Posterior Axillary Boost in Relation to BMI

Background: The axillary and supraclavicular nodal volume treatment results in improvement of local control and survival after breast conserving surgery (BCS) or modified radical mastectomy (MRM). Studies on the depth of these nodes have questioned the consistent use of standard fields for all patients. This study was done to assess the dose delivery to these lymph nodes with conventional treatment techniques according to body mass index (BMI). Methods: Twenty six patients with breast cancer undergoing breast surgery were included and computed tomography (CT) simulation was done. Their axillary and supraclavicular nodal volumes were contoured for planning target volume (PTV). Supraclavicular and posterior axillary fields were generated for each patient with digital reconstruction radiography (DRR) technique. Then the dose distribution of the two conventional methods - anterior-posterior field (AP), and anterior field with posterior boost (AP+PA boost) - for total dose of 5000 cGy, was examined with radiotherapy dose plan program. An AP planned field suitable for PTV, was designed and compared to AP+PA boost. The diameter of axilla was measured at the center of AP field in CT scan. Data were analyzed in relationship to BMI. Results: PTV coverage and excessively irradiating normal tissues (hot points), proved to have significant differences in each method (p < 0.001 to 0.01). Axillary and supraclavicular LNs were in 1.6 to 10 and 0.5 to 6.3 cm depth, respectively. Depth of the prescribed dose, which was gained from planned field, had a significant statistical association with BMI (p < 0.05). Conclusions: Current standard fields are not appropriate for all patients, because of poor coverage of PTV. To sum up, 3D CT planning is strongly recommended for patients with high BMI