Amniotic Allograft, A Possible Alternative to Free Gingival Graft in Improving Attached Gingiva Width: A Randomized Controlled Clinical Trial.

Background: Years of research have well demonstrated the pivotal role the attached gingiva plays in maintaining of periodontal health. Objective: This study aimed to compare the efficacy of two technics, amniotic allograft and free gingival graft (FGG), in improving the attached gingiva width (AGW) around the teeth. Methods: In this randomized controlled clinical trial study, 28 patients all in need of increased AGW were randomly halved and assigned to a test group receiving the amniotic allograft and a control group treated by a palatal FGG. Following the operation, the mean AGW, graft shrinkage, and color match were assessed and photographed at various intervals (1, 2, 6, and 12 weeks). The level of pain was also evaluated based on the visual analog scale (VAS). Results: The AGW was not significantly different between the two groups in 2, 6 and, 12 weeks postoperatively (P=0.17, 0.73, 0.76 respectively). The same applied to the amount of shrinkage between the two groups at the intervals (p=0.38, p=0.57 and p=0.52 respectively). The amniotic allograft group was superior (not significantly) in terms of the color match (p=0.59, p=0.31 and p=0.18 respectively). However, it was found to have significantly lower VAS pain scores than did the control group (p <0.05). Conclusion: Application of the amniotic allograft could decrease the postoperative pain as well as discomfort and effectively increase the AGW. Therefore, given the drawbacks of FGG, the amniotic allograft can be considered as a viable alternative.

Complexity Collapse, Fluctuating Synchrony, and Transient Chaos in Neural Networks With Delay Clusters.

Neural circuits operate with delays over a range of time scales, from a few milliseconds in recurrent local circuitry to tens of milliseconds or more for communication between populations. Modeling usually incorporates single fixed delays, meant to represent the mean conduction delay between neurons making up the circuit. We explore conditions under which the inclusion of more delays in a high-dimensional chaotic neural network leads to a reduction in dynamical complexity, a phenomenon recently described as multi-delay complexity collapse (CC) in delay-differential equations with one to three variables. We consider a recurrent local network of 80% excitatory and 20% inhibitory rate model neurons with 10% connection probability. An increase in the width of the distribution of local delays, even to unrealistically large values, does not cause CC, nor does adding more local delays. Interestingly, multiple small local delays can cause CC provided there is a moderate global delayed inhibitory feedback and random initial conditions. CC then occurs through the settling of transient chaos onto a limit cycle. In this regime, there is a form of noise-induced order in which the mean activity variance decreases as the noise increases and disrupts the synchrony. Another novel form of CC is seen where global delayed feedback causes "dropouts," i.e., epochs of low firing rate network synchrony. Their alternation with epochs of higher firing rate asynchrony closely follows Poisson statistics. Such dropouts are promoted by larger global feedback strength and delay. Finally, periodic driving of the chaotic regime with global feedback can cause CC; the extinction of chaos can outlast the forcing, sometimes permanently. Our results suggest a wealth of phenomena that remain to be discovered in networks with clusters of delays.

Dynamical invariants and inverse period-doubling cascades in multi-delay systems.

We investigate transitions to simple dynamics in first-order nonlinear differential equations with multiple delays. With a proper choice of parameters, a single delay can destabilize a fixed point. In contrast, multiple delays can both destabilize fixed points and promote high-dimensional chaos but also induce stabilization onto simpler dynamics. We show that the dynamics of these systems depend on the precise distribution of the delays. Narrow spacing between individual delays induces chaotic behavior, while a lower density of delays enables stable periodic or fixed point behavior. As the dynamics become simpler, the number of unstable roots of the characteristic equation around the fixed point decreases. In fact, the behavior of these roots exhibits an astonishing parallel with that of the Lyapunov exponents and the Kolmogorov-Sinai entropy for these multi-delay systems. A theoretical analysis shows how these roots move back toward stability as the number of delays increases. Our results are based on numerical determination of the Lyapunov spectrum for these multi-delay systems as well as on permutation entropy computations. Finally, we report how complexity reduction upon adding more delays can occur through an inverse period-doubling sequence.

Assessment of the strain depth sensitivity of Moiré sampling Scanning Transmission Electron Microscopy Geometrical Phase Analysis through a comparison with Dark-Field Electron Holography.

In this study, the Moiré sampling Scanning Transmission Electron Microscopy Geometrical Phase Analysis (or STEM Moiré GPA) strain characterization method is compared to the well-established Dark-Field Electron Holography technique on a thin film stack grown by Molecular Beam Epitaxy. While experimental data obtained with the two techniques are, overall, in good qualitative agreement, small statistically relevant differences are locally observed between the two methods. The results obtained from both techniques are further confronted with Finite Element Method (FEM) mechanical simulations modeling the strain relaxation phenomena from a thin lamella. The FEM simulation highlights a non-uniform deformation field along the beam propagation direction with a higher deformation level near the surface of the lamella compared to the center of the same lamella. The center-surface strain differences obtained from modeling are consistent with the experimentally derived differences accounting for the fact that the SMG method is sensitive to the strain state of the surface of the lamella with a very narrow depth-of-field, and the DFEH technique is measuring the strain state of the center of the same lamella averaging over a large section of the thickness. The depth-of-field difference between both methods can be reasonably related to their respective contrast mechanisms (STEM vs Conventional Transmission Electron Microscopy). As the SMG method is using a convergent probe, the narrow depth-of-field might be used to sense the deformation field over different sections of the lamella using the defocus and potentially retrieve the three-dimensional strain field.

Sampling optimization of Moiré geometrical phase analysis for strain characterization in scanning transmission electron microscopy.

A strain characterization technique in a Scanning Transmission Electron Microscope (STEM) called "STEM Moiré GPA" (SMG) emerged recently as an efficient method to map the deformation field on large field of views (up to few microns in length scale). The technique is based on the interference between the scanning grid of the STEM electron probe and the periodic lattice of a crystalline material. The interference pattern (STEM Moiré hologram) is the result of an undersampling artifact, commonly named aliasing, occurring when less than two pixels are used to record a lattice spacing. The phase of the STEM Moiré fringes embeds the crystalline structure of the sample, and the variation of the phase can be related to a deformation field. To acquire a STEM Moiré hologram, the current practice is limited to choosing the periodicity of the scanning grid (pixel spacing) close to one lattice spacing. Such empirical recommendations are, however, insufficient since multiple lattice spacings are undersampled at once. The aliased spatial frequencies can overlap with each other in Fourier space making the STEM Moiré hologram not suitable for Geometric Phase Analysis (GPA) processing. In this study, a procedure is proposed to choose the optimal sampling parameters (pixel spacing and scanning rotation) for the STEM Moiré GPA application on any single crystal material. The procedure is then applied on a InP/InAs1-xPx/InP stack grown by Molecular Beam Epitaxy (MBE). Deformation profiles from different sampling conditions are compared to the established High-Resolution STEM GPA method, highlighting the reliability of the SMG method following the optimization process. The optimization protocol and the limits of SMG are finally discussed, and a generalization of the coherent sampling concept is proposed.

Brain-dead Donation Rate in Month of Ramadan and the other Months: 2005-2014.

Regardless of the level of development, religion and beliefs have crucial impact on people's attitude towards organ donation. Although organ donation in Islam is obviously appraised, mainly due to lack of an appropriate infrastructure, post-mortem donation rate in Islamic countries is not comparable to successful settings. We conducted this study to assess the extent of contribution of factors that reduce the level of effectiveness, and also to determine the impact of altruistic feelings in the month of Ramadan on family refusal as the leading modifiable contributor to organ donation rate. All records of potential and actual brain-dead donors, referred to Organ Procurement Unit of the Iranian Tissue Bank, from January 1, 2005 to December 31, 2014, were analyzed. In each year, the number of potential and actual donors in the month of Ramadan was compared to the mean value in the remaining 11 months. Of 1758 total potential donors in 10 years, 464 cases became actual donors (26.4% as overall level of effectiveness). The reasons for non-effectiveness were medical contraindications (25.4%), cardiac arrest before referral or during maintenance (7.4%), family refusal (30.8%), judicial refusal (8.7%), etc (1.3%). Analysis showed no significant differences between donation rates (both potential and actual) in Ramadan and non-Ramadan months for potential (Δ=3.55, 95% CI: -6.7 to 13.8) and actual donors (Δ=1.35, 95% CI: -2.3 to 5). Despite the undeniable role of religion and beliefs in the establishment of organ procurement program from brain-dead donors, there was no monthly variability in post-mortem organ donation rate.

Human Split-Thickness Skin Allograft from Brain-Dead Donors.

BACKGROUND: Looking for an appropriate skin substitute for temporary and permanent coverage of wounds remains one of the main obstacles of medical researchers. OBJECTIVE: To investigate the rate of inflammation, symbiosis, and survival of grafted allograft skin from brain-dead donors (BDDs) in rabbits. METHODS: After receiving negative serologic tests of BDDs, we prepared partial thickness skin grafts. They were then used in treating wounds of 5 rabbits in comparison with split-thickness skins taken from cardiac dead donors. RESULTS: On histopathological examinations, we found no difference between the skins. All samples were separated from the baseline in 15-20 days. CONCLUSION: Gamma-irradiated freeze-dried human split-thickness skin taken from BDDs is safe and can be used for the treatment of deep skin burns.

Do spinal cord-injured individuals with stronger sense of coherence use different psychological defense styles?

OBJECTIVES: Although the importance of sense of coherence (SOC) and psychological defense mechanisms (PDMs) in the process of coping has been demonstrated, it has not yet been clarified whether individuals with stronger SOC use specific PDMs. STUDY DESIGN: Cross-sectional. SETTING: Iran. METHODS: Demographic and injury-related variables including injury level, time since injury, American Spinal Cord Association (ASIA) Scale and Spinal cord independence measure-III were collected among individuals with spinal cord injury (SCI). SOC was assessed by the Short-form Sense of Coherence Scale. PDMs were identified using 40-version of the Defense Style Questionnaire. RESULTS: Neurotic defense style was the most commonly used style especially. The overall most commonly used PDM was 'rationalization', which was used by 95%. Individuals with stronger SOC used more mature style (P=0.001, r=0.52), particularly 'humor' and 'suppression' mechanisms (P<0.0001 and 0.024, respectively). There was a negative correlation between stronger SOC and the use of immature defenses including passive aggression (P=0.001, r=-0.51), acting out (P=0.001, r=-0.48), isolation (P=0.009, r=-0.50), autistic fantasy (P=0.010, r=-0.30) and somatization (P<0.0001, r=-0.62). Married individuals had significantly stronger SOC (P=0.01). Age, gender, age at the time of injury incidence, time since injury, ASIA score and cause of injury were not determinants of SOC. CONCLUSION: In this study, PDMs, which are more probable to be used by individuals with stronger SOC, have been identified. Mature defenses including 'humor' and 'suppression' are used by stronger SOC more often, whereas immature mechanisms are less likely to be used.

Glutaredoxin 2a overexpression in macrophages promotes mitochondrial dysfunction but has little or no effect on atherogenesis in LDL-receptor null mice.

AIMS: Reactive oxygen species (ROS)-mediated formation of mixed disulfides between critical cysteine residues in proteins and glutathione, a process referred to as protein S-glutathionylation, can lead to loss of enzymatic activity and protein degradation. Since mitochondria are a major source of ROS and a number of their proteins are susceptible to protein-S-glutathionylation, we examined if overexpression of mitochondrial thioltranferase glutaredoxin 2a (Grx2a) in macrophages of dyslipidemic atherosclerosis-prone mice would prevent mitochondrial dysfunction and protect against atherosclerotic lesion formation. METHODS AND RESULTS: We generated transgenic Grx2aMac(LDLR-/-) mice, which overexpress Grx2a as an EGFP fusion protein under the control of the macrophage-specific CD68 promoter. Transgenic mice and wild type siblings were fed a high fat diet for 14 weeks at which time we assessed mitochondrial bioenergetic function in peritoneal macrophages and atherosclerotic lesion formation. Flow cytometry and Western blot analysis demonstrated transgene expression in blood monocytes and peritoneal macrophages isolated from Grx2aMac(LDLR-/-) mice, and fluorescence confocal microscopy studies confirmed that Grx2a expression was restricted to the mitochondria of monocytic cells. Live-cell bioenergetic measurements revealed impaired mitochondrial ATP turnover in macrophages isolated from Grx2aMac(LDLR-/-) mice compared to macrophages isolated from non-transgenic mice. However, despite impaired mitochondrial function in macrophages of Grx2aMac(LDLR-/-) mice, we observed no significant difference in the severity of atherosclerosis between wildtype and Grx2aMac(LDLR-/-) mice. CONCLUSION: Our findings suggest that increasing Grx2a activity in macrophage mitochondria disrupts mitochondrial respiration and ATP production, but without affecting the proatherogenic potential of macrophages. Our data suggest that macrophages are resistant against moderate mitochondrial dysfunction and rely on alternative pathways for ATP synthesis to support the energetic requirements.

Fabrication of a hard tissue replacement using natural hydroxyapatite derived from bovine bones by thermal decomposition method.

BACKGROUND: For the treatment of bone defects that exceed the critical size of the injury, several therapies have been investigated. Thermal decomposition method is suggested for extraction of natural hydroxyapatite bioceramic (HA). This technique in comparison with other methods of producing HA, has less complexity and greater economic efficiency. OBJECTIVE: In the present study, a thermal decomposition method is suggested for extraction of natural HA from bovine femur bones. METHODS: In this experiment, to extract the ceramic material, the bone samples were first de-fatted and ground to particles less than 420 µm, and also 420-500 µm, respectively. Prepared powders were heated at 170 °C for 24 h, and then divided into two groups for 6 h. The first group was heated at 750 °C; the second group was heated at 850 °C. The calcium phosphate compounds were obtained with complete elimination of the organic phase of the bone. These bioceramic compounds were characterized physiochemically by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). RESULTS: We found that the powder heated at 750 °C in two dimensional scales was rich in carbonated hydroxyapatite, and therefore, eminently suitable for using in hard tissue replacements. However, increasing the temperature up to 850 °C reduced the Ca/P ratio to 1.5 in the powder sample sizes less than 420 µm. Consequently, the obtained composition became rather similar to the chemical formula of tricalcium phosphate (TCP) that is appropriate in tissue engineering and drug delivery applications. CONCLUSION: The observations affirmed that by eliminating the collagen and other organic materials existing in the bovine bones, the mineral phase of the bone had the potential of transformation to nano-particles. To investigate the repair of critical-size bone defects and bone augmentation, cylindrical blocks were fabricated by applying different pressures of 150, 160 and 170 MPa. The structure and compressive strength of the pressed samples after sintering at 1200 °C were characterized by SEM and compressive strength test.

Human split-thickness skin allograft: skin substitute in the treatment of burn.

BACKGROUND: Human skin allograft has been used as wound coverage for a long time; it is one of the most successful and widely used dressings for burn wounds in the world. OBJECTIVE: To prepare a freeze-dried human split-thickness skin allograft and evaluate its cytotoxicity, the structure and physical properties after processing methods and clinical efficacy in burn patients. METHODS: After ensuring tissue safety, we lyophilized human cadaveric partial thickness skin and exposed it to gamma radiation. Histopathological and immunohistochemical properties, tensile strength and in vitro cytotoxicity were assayed for the skin samples. Then, we tested the samples in 11 patients with deep skin burn. RESULTS: On histological and histopathological examinations, we found a normal skin structure. The tensile strength of the rehydrated freeze-dried human skin allograft was not lesser than the fresh human skin. Cell viability in MTT testing was more than 95%. None of our patients showed any signs of immunological reactions or complications. CONCLUSION: Gamma-irradiated freeze-dried human split-thickness skin is safe and non-toxic and can be used for the treatment of patients with deep skin burn.

Comparative study of depression and consent among brain death families in donor and nondonor groups from March 2001 to December 2002 in Tehran.

OBJECTIVE: The aim of this research was to study the relationship between depression and organ donation among families of brain death cases. MATERIALS AND METHODS: This descriptive, cross-sectional study included a sample of first-degree relatives of brain death cases: 54 relatives among 27 organ donor families and 104 relatives among 58 nonorgan donor families participated in the research by the counting method. All families were questioned about their willingness for organ donation and at least 3 months had passed from their relative's death to the time we performed the research. Data were collected via a demographic questionnaire and Beck depression inventory (BDI) with a cutoff point of 16; persons with scores over 16 were considered depressed. Data were analyzed using descriptive statistics, Student t test, and chi-square test. RESULTS: Depression was observed in 20.4% of donor families and 17.3% of nondonor families; there was no significant difference between them. There were no significant differences in the frequency of depression between parents, spouses, and children of the 2 groups. The organ donors' relatives reported the effectiveness of organ donation to alleviate their grief: 66% completely and 32% partially. CONCLUSION: Organ donation does not have a significant effect on the course of grief and later depression among relatives of brain death cases.

Peripheral blood dendritic cells are phenotypically and functionally intact in chronic hepatitis B virus (HBV) infection.

Persistence of hepatitis B virus (HBV) infection is associated with reduced anti-viral T cell responses. Impaired dendritic cell (DC) function was suggested as the cause of reduced T cell stimulation in chronic HBV carriers. Thus, we compared myeloid (mDC) and plasmacytoid DC (pDC) from chronic HBV carriers and controls. Frequency and phenotype of isolated DC were analysed by fluorescence activated cell sorter staining, DC function by mixed lymphocyte reaction, cytokine bead array, intracellular cytokine staining, enzyme-linked immunosorbent assay and enzyme-linked immunospot. Expression of HBV DNA and mRNA was studied by polymerase chain reaction (PCR). Circulating total DC, mDC or pDC were not reduced in chronic HBV carriers. Isolated mDC and pDC from chronic HBV carriers exhibited similar expression of co-stimulatory molecules and alloreactive T helper cell stimulation as control DC, whether tested directly ex vivo or after in vitro maturation. Secretion of pro- and anti-inflammatory cytokines by CD40 or Toll-like receptor ligand-stimulated patient DC was intact, as was human leucocyte antigen A2-restricted HBV-specific cytotoxic lymphocyte stimulation. Although both DC populations contained viral DNA, viral mRNA was undetectable by reverse transcription-PCR, arguing against viral replication in DC. We found no quantitative, phenotypic or functional impairment of mDC or pDC in chronic hepatitis B, whether studied ex vivo or after in vitro maturation.

Role of the nitric oxide pathway and the endocannabinoid system in neurogenic relaxation of corpus cavernosum from biliary cirrhotic rats.

BACKGROUND AND PURPOSE: Relaxation of corpus cavernosum, which is mediated by nitric oxide (NO) released from non-adrenergic non-cholinergic (NANC) neurotransmission, is critical for inducing penile erection and can be affected by many pathophysiological conditions. However, the peripheral effect of liver cirrhosis on erectile function is as yet unknown. The aim of the present study was to investigate the effect of biliary cirrhosis on NANC-mediated relaxation of rat corpus cavernosum and the possible roles of endocannabinoid and nitric oxide systems in this model. EXPERIMENTAL APPROACH: Cirrhosis was induced by bile duct ligation. Controls underwent sham operation. Four weeks later, strips of corpus cavernosum were mounted in a standard organ bath and NANC-mediated relaxations were obtained by applying electrical field stimulation. KEY RESULTS: The NANC-mediated relaxation was enhanced in corporal strips from cirrhotic animals. Anandamide potentiated the relaxations in both groups. Either AM251 (CB(1) antagonist) or capsazepine (vanilloid VR(1) antagonist), but not AM630 (CB(2) antagonist), prevented the enhanced relaxations of cirrhotic strips. Either the non-selective NOS inhibitor L-NAME or the selective neuronal NOS inhibitor L-NPA inhibited relaxations in both groups, but cirrhotic groups were more resistant to the inhibitory effects of these agents. Relaxations to sodium nitroprusside (NO donor) were similar in tissues from the two groups. CONCLUSIONS AND IMPLICATIONS: Cirrhosis potentiates the neurogenic relaxation of rat corpus cavernosum probably via the NO pathway and involving cannabinoid CB(1) and vanilloid VR(1) receptors.

Abnormal viscoelastic behaviour of passive ankle joint movement in diabetic patients: an early or a late complication?

AIMS/HYPOTHESIS: The goal of the present study was to compare the range of motion and both the viscous and elastic components of passive ankle joint movement in short- and long-term diabetic patients with that of a control population. METHODS: Thirty-four diabetic patients and 16 control subjects entered into the study. Patients with a history of over 15 years of diabetes were considered as a long-term diabetic group. In order to quantify the passive ankle joint movement, a device was designed to measure the dorsi- and plantar-flexion angle and the net moment at the ankle. Elastic behaviour was examined as the separate slope of regression lines (stiffness) of plantar and dorsal components in the loading moment-angle curve. It was also examined as the slope of the regression line in the final 10% of each component. Hysteresis, a characteristic of viscoelastic materials that indicates loss of energy during unloading, was corrected for range of motion and used to examine viscous behaviour of the ankle joint. RESULTS: Total and plantar ranges of motion were significantly lower in long-term diabetic patients than in short-term diabetic and control groups (p < 0.05). Plantar-flexion stiffness was significantly lower in short-term diabetic patients than in control subjects and long-term diabetic groups (p < 0.05). Corrected hysteresis was significantly higher in long-term diabetic than in short-term diabetic and control (p < 0.05) groups in the dorsal range of motion. CONCLUSIONS/INTERPRETATION: This study shows that both decreased plantar and total ankle joint ranges of motion, and increased viscous component of passive ankle joint movement are among the late complications of diabetes.

Adhesive bonding of medical and implantable devices.

Although there are many commercially available medical-grade adhesives, their use for new applications requires detailed investigation. It is also important that as well as the initial joint strength, durability of the bonded components during intended use, including exposure to low and high temperatures, stress, fluids and sterilisation, are investigated. Design of accelerated ageing tests, which can simulate the service environments, is critical in providing realistic durability data. Interpretation of ageing data and lifetime prediction of the joint is essential in assessing the performance of medical devices. Emergence of new types of adhesives as well as further development of precision dispensing and rapid-curing technologies offer many exciting and commercially attractive opportunities for joining medical devices.

Prostaglandin E(2)-induced interleukin-6 release by a human airway epithelial cell line.

Human airway epithelial cell release of interleukin (IL)-6 in response to lipid mediators was studied in an airway cell line (BEAS-2B). Prostaglandin (PG) E(2) (10(-7) M) treatment caused an increase in IL-6 release at 2, 4, 8, and 24 h. IL-6 release into the culture medium at 24 h was 3,396 +/- 306 vs. 1,051 +/- 154 pg/ml (PGE(2)-treated cells vs. control cells). PGE(2) (10(-7) to 10(-10) M) induced a dose-related increase in IL-6 release at 24 h. PGF(2 alpha) (10(-6) M) treatment caused a similar effect to that of PGE(2) (10(-7) M). PGE(2) analogs with relative selectivity for PGE(2) receptor subtypes were studied. Sulprostone, a selective agonist for the EP-3 receptor subtype had no effect on IL-6 release. 11-Deoxy-16,16-dimethyl-PGE(2), an EP-2/4 agonist, and 17-phenyl trinor PGE(2), an agonist selective for the EP-1 > EP-3 receptor subtype (10(-6) to 10(-8) M), caused dose-dependent increases in IL-6 release. 8-Bromo-cAMP treatment resulted in dose-related increases in IL-6 release. RT-PCR of BEAS-2B cell mRNA demonstrated mRNA for EP-1, EP-2, and EP-4 receptors. After PGE(2) treatment, increases in IL-6 mRNA were noted at 4 and 18 h. Therefore, PGE(2) increases airway epithelial cell IL-6 production and release.

Serum proteins and erythrocyte enzymes of populations in Iran.

The genetic polymorphisms of nine biochemical genetic markers were investigated in four populations (Turks, Kurds, Tehranis and Kermanis) living in the north-east and south-east regions of Iran. Only one of the nine loci studied (acid phosphatase) showed significant gene frequency differences and for the C3 system the F allele frequencies in these populations were the lowest ever reported from Iran.