Antibacterial and Cellular Behaviors of Novel Zinc-Doped Hydroxyapatite/Graphene Nanocomposite for Bone Tissue Engineering.

Bacteria are one of the significant causes of infection in the body after scaffold implantation. Effective use of nanotechnology to overcome this problem is an exciting and practical solution. Nanoparticles can cause bacterial degradation by the electrostatic interaction with receptors and cell walls. Simultaneously, the incorporation of antibacterial materials such as zinc and graphene in nanoparticles can further enhance bacterial degradation. In the present study, zinc-doped hydroxyapatite/graphene was synthesized and characterized as a nanocomposite material possessing both antibacterial and bioactive properties for bone tissue engineering. After synthesizing the zinc-doped hydroxyapatite nanoparticles using a mechanochemical process, they were composited with reduced graphene oxide. The nanoparticles and nanocomposite samples were extensively investigated by transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Their antibacterial behaviors against Escherichia coli and Staphylococcus aureus were studied. The antibacterial properties of hydroxyapatite nanoparticles were found to be improved more than 2.7 and 3.4 times after zinc doping and further compositing with graphene, respectively. In vitro cell assessment was investigated by a cell viability test and alkaline phosphatase activity using mesenchymal stem cells, and the results showed that hydroxyapatite nanoparticles in the culture medium, in addition to non-toxicity, led to enhanced proliferation of bone marrow stem cells. Furthermore, zinc doping in combination with graphene significantly increased alkaline phosphatase activity and proliferation of mesenchymal stem cells. The antibacterial activity along with cell biocompatibility/bioactivity of zinc-doped hydroxyapatite/graphene nanocomposite are the highly desirable and suitable biological properties for bone tissue engineering successfully achieved in this work.

Micromechanical modeling of rate-dependent behavior of Connective tissues.

In this paper, a constitutive and micromechanical model for prediction of rate-dependent behavior of connective tissues (CTs) is presented. Connective tissues are considered as nonlinear viscoelastic material. The rate-dependent behavior of CTs is incorporated into model using the well-known quasi-linear viscoelasticity (QLV) theory. A planar wavy representative volume element (RVE) is considered based on the tissue microstructure histological evidences. The presented model parameters are identified based on the available experiments in the literature. The presented constitutive model introduced to ABAQUS by means of UMAT subroutine. Results show that, monotonic uniaxial test predictions of the presented model at different strain rates for rat tail tendon (RTT) and human patellar tendon (HPT) are in good agreement with experimental data. Results of incremental stress-relaxation test are also presented to investigate both instantaneous and viscoelastic behavior of connective tissues.

Stable silencing of IGF1R using Lentiviral-mediated shRNA in HEK293T cells.

Insulin-like growth factors are among the peptide mitogens that regulate cell proliferation and differentiation as well as mediator of antiapoptotic signals. The imbalance between the expression and activities of these molecules may lead to malignancy in cells. Evidences have suggested the insulin-like growth factor 1 receptor (IGF-1R) signaling pathway as a therapeutic target in the management and treatment of cancer. In this present study, we have generated silencing stable clones of HEK cells using six different pGIPZ (lentiviral vector) shRNAs targeted to human IGF-1R gene and a pGIPZ non-silencing shRNAmir lentiviral vector (as negative control). The recombinant lentiviral vectors were separately transduced into human embryonic kidney 293 T (HEK293T) cell lines. The knockdown of IGF-1R was confirmed by reverse transcription polymerase chain reaction (RT-PCR) and the relative IGF-1R mRNA levels were expressed as a ratio of IGF-1R to ß-actin by REST software. The results showed significant reduction in the expression of IGF-1R mRNAs in cells transduced with all six pGIPZ-IGF-1R recombinant lentivirals compared to non-silencing negative control. No significant difference was observed among the six cassettes. Results indicated that recombinant lentiviral vectors provided an efficient and stable knockdown of IGF-1R providing useful tool for IGF-1R pathway studies.

Evaluation of a novel lentiviral vaccine expressing KMP11-HASPB fusion protein against Leishmania infantum in BALB/c mice.

Hydrophilic acylated surface protein B (HASPB) is an immunogenic Leishmania protein against which antibodies are produced in the sera of cutaneous and visceral Leishmaniasis (VL) patients. Kinetoplastid membrane protein 11 (KMP11) is another protein antigen of Leishmania which is reported as a promising candidate for vaccination of VL. It is a highly conserved surface protein present in all members of kinetoplastid family and is expressed in both promastigotes and amastigotes. In this study, the coding sequence of KMP11 and HASPB was cloned into a pCDH-cGFP lentiviral vector as a fusion protein. The gene expression was confirmed using RT-PCR and Western blot methods. After injection of the recombinant KMP11-HASPB-expressing lentiviruses to BALB/c mice, using ELISA technique, a significant increase in IFN-γ and IL-4 as well as IgG1 and IgG2a was observed compared to the control group. Furthermore, the number of parasites in the liver and spleen of vaccinated mice decreased significantly compared with the control group.

Online Estimation of Elbow Joint Angle Using Upper Arm Acceleration: A Movement Partitioning Approach.

Estimating the elbow angle using shoulder data is very important and valuable in Functional Electrical Stimulation (FES) systems which can be useful in assisting C5/C6 SCI patients. Much research has been conducted based on the elbow-shoulder synergies. The aim of this study was the online estimation of elbow flexion/extension angle from the upper arm acceleration signals during ADLs. For this, a three-level hierarchical structure was proposed based on a new approach, i.e. 'the movement phases'. These levels include Clustering, Recognition using HMMs and Angle estimation using neural networks. ADLs were partitioned to the movement phases in order to obtain a structured and efficient method. It was an online structure that was very useful in the FES control systems. Different initial locations for the objects were considered in recording the data to increase the richness of the database and to improve the neural networks generalization. The cross correlation coefficient (K) and Normalized Root Mean Squared Error (NRMSE) between the estimated and actual angles, were obtained at 90.25% and 13.64%, respectively. A post-processing method was proposed to modify the discontinuity intervals of the estimated angles. Using the post-processing, K and NRMSE were obtained at 91.19% and 12.83%, respectively.

Seroepidemiology of Neospora caninum infection in dairy cattle herds in Mashhad area, Iran.

A seroepidemiology study of Neospora caninum was conducted in Mashhad area, Khorasan province, Iran on 337 cattle from 30 dairy using ELISA. All herds had seropositive cattle and antibodies were formed in 46% of the cattle. Abortion was significantly associated with seropositivity of cattle. The highest risk of abortion was observed in the 1-2-year-old cows. Our results indicate that Neospora infection is widespread in Iran.

Micromechanics and constitutive modeling of connective soft tissues.

In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical homogenization method with the help of ABAQUS software. The periodic boundary conditions and the proposed constitutive models are implemented into ABAQUS using the DISP and the UMAT subroutines, respectively. The existence of the solution and stable material behavior of proposed constitutive model for collagen fibers are investigated based on the poly-convexity condition. Results of the presented micromechanics model for connective tissues are compared and validated with available experimental data. Effects of geometrical and material parameters variation at microscale on macroscopic mechanical behavior of tissues are investigated. The results show that decrease in collagen content of the connective tissues like the tendon due to diseases leads 20% more stretch than healthy tissue under the same load which can results in connective tissue malfunction and hypermobility in joints.

Ultrasonic measurement of breast tissue motion and the implications for velocity estimation.

A high-resolution study of breast tissue motion during cardiac systole and respiration is presented. An experimental system was designed to achieve a velocity resolution on the order of 1 mm/s with high spatial resolution. The peak velocity of tissue motion estimated during cardiac systole ranged from 0.2 mm/s to 5.6 mm/s among the subjects studied. It is shown that motion due to the cardiac cycle is less significant when the subject is positioned on the side rather than supine. The mean tissue velocity among subjects in the supine position is 2.88 mm/s and drops to 0.81 mm/s for the side position, with a corresponding spatial displacement of 0.095 mm, dropping to 0.027 mm. The velocity profiles indicate that 100 ms is required for the entire ribcage contraction-relaxation process to occur. Experiments using a prone biopsy table show the almost complete elimination of tissue motion due to cardiac systole, suggesting that the use of the table eliminates this motion, thus allowing for high-resolution blood velocity estimates. Features resulting from respiratory motion are also presented. We found this motion to be of a much longer time duration, and of a much higher magnitude, with velocities as high as 29 mm/s. The implications of the study on the high-resolution estimation of blood velocity and high-resolution breast imaging are discussed.

Mean curvature evolution and surface area scaling in image filtering.

Representing the image as a surface, an inhomogeneous diffusion algorithm is developed, evolving the surface at a speed proportional to its mean curvature, reducing noise while preserving image structure. An adaptive scaling parameter increases the speed of the diffusion. The properties of a discrete algorithm are demonstrated experimentally.

Removing ECG Artifact from the Surface EMG Signal Using Adaptive Subtraction Technique.

BACKGROUND: The electrocardiogram artifact is a major contamination in the electromyogram signals when electromyogram signal is recorded from upper trunk muscles and because of that the contaminated electromyogram is not useful. Objective : Removing electrocardiogram contamination from electromyogram signals. METHODS: In this paper, the clean electromyogram signal, electrocardiogram artifact and electrocardiogram signal were recorded from leg muscles, the pectoralis major muscle of the left side and V4, respectively. After the pre-processing, contaminated electromyogram signal is simulated with a combination of clean electromyogram and electrocardiogram artifact. Then, contaminated electromyogram is cleaned using adaptive subtraction method. This method contains some steps; (1) QRS detection, (2) formation of electrocardiogram template by averaging the electrocardiogram complexes, (3) using low pass filter to remove undesirable artifacts, (4) subtraction. RESULTS: Performance of our method is evaluated using qualitative criteria, power spectrum density and coherence and quantitative criteria signal to noise ratio, relative error and cross correlation. The result of signal to noise ratio, relative error and cross correlation is equal to 10.493, 0.04 and %97 respectively. Finally, there is a comparison between proposed method and some existing methods. CONCLUSION: The result indicates that adaptive subtraction method is somewhat effective to remove electrocardiogram artifact from contaminated electromyogram signal and has an acceptable result.

Glycemic index, glycemic load and their association with glycemic control among patients with type 2 diabetes.

BACKGROUND/OBJECTIVES: The aim was to investigate the associations of glycemic index (GI), glycemic load (GL), carbohydrate and fiber intakes with hyperglycemia in type 2 diabetic patients. SUBJECTS/METHODS: In a cross-sectional study of 640 type 2 diabetic patients aged 28-75 years, usual dietary intakes were assessed by validated food frequency questionnaire. We used published international and Iranian tables of GI based on the white bread. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI). RESULTS: High-GL diet was associated with higher risk of hyperglycemia in type 2 diabetic patients after controlling for potential confounders. In multivariable model, OR (95% CI) for the highest vs the lowest quartile of GL was 2.58 (1.08-6.15) for elevated fasting serum glucose (FSG) (>130 mg/dl) (P(trend) = 0.02) and was 3.05 (1.33-7.03) for elevated HbA1c (>8.6%) (P(trend)=0.008). After additional adjusting for dietary fiber and protein intakes, the relation of GL with elevated FSG and HbA1c was stable. GI was not significantly associated with either elevated FSG or HbA1c. In multivariable model, OR (95% CI) for the highest vs lowest quartile of the substitution of dietary carbohydrate for fat intake was 2.32 (1.37-3.92) for elevated HbA1c (P(trend) = 0.001). Higher intake of dietary fiber was associated with lower risk of elevated FSG (highest vs lowest quartile: OR, 0.53; 95% CI: 0.28-0.99; P(trend) = 0.04), but not with lower risk of elevated HbA1c. CONCLUSIONS: GL and carbohydrate intake were positively associated with the risk of hyperglycemia in type 2 diabetic patients; but the benefit in pursuing a low-GI diet without considering carbohydrate and energy intakes in these patients should be further investigated.

Effect of early interferon beta-1a therapy on conversion to multiple sclerosis in Iranian patients with a first demyelinating event.

BACKGROUND: A new treatment approach to multiple sclerosis (MS) is the initiation of interferon therapy in the early phase of the disease when a patient presents with clinically isolated syndrome. AIMS OF THE STUDY: The goal of this study was to assess the effect of early treatment on the risk of conversion to clinically definite MS in Iranian patients. METHODS: Eligible patients had presented with a first episode of neurological dysfunction suggesting MS within the previous 3 months and had abnormal brain magnetic resonance imaging (MRI). Patients were randomly assigned to receive intramuscular interferon beta 1a 30 mug or placebo once a week for 3 years. RESULTS: Of the 217 patients randomized, 202 patients completed the study; 104 received Avonex and 98 received placebo. Fewer patients converted to clinically definite multiple sclerosis in the treated group than in the placebo group during the study (36.6% vs 58.2%, P < 0.003). The number of active T2-weighted MRI lesions was significantly lower in the treated group. CONCLUSIONS: The results of our study, which are consistent with those from western studies, show that treatment at an early stage of MS delays conversion to definite MS and has positive effects on MRI outcomes.

First report of Neospora caninum-associated bovine abortion in Mashhad area, Iran.

Neospora caninum is an apicomplexan protozoan which causes abortion in cattle worldwide. The present study was designed to assess the importance of bovine neosporosis for causing abortion in Iranian cattle. Infection was primarily diagnosed by polymerase chain reaction (PCR), complemented with histopathology and immunohistochemistry (IHC). One hundred brains of aborted bovine fetuses were collected from Iranian dairy herd between 2003 and 2005 in Mashhad area. N. caninum was detected by PCR in the brains of 13 aborted fetuses. Lesions consistent with N. caninum infection were observed in 12 of fetal brains. Immunohistochemical examination of brain detected N. caninum organisms in three aborted fetuses, and a thick-walled (2 mum) cyst with 50 mum diameter was identified in one of the IHC-positive brain. The results indicated that neosporosis is an important cause of abortion in dairy cattle of Iran.

Treatment of early onset multiple sclerosis with suboptimal dose of interferon beta-1a.

BACKGROUND: Patients with early onset multiple sclerosis may develop disability at a younger age than adults. There are several reports about safety of beta interferons in childhood and juvenile MS with different doses. OBJECTIVES: To determine safety and efficacy of substandard dose of intramuscular interferon beta-1a in a prospective randomized trial in patients with multiple sclerosis under the age of 16. METHODS: Sixteen patients were divided into two groups randomly. The first group was treated with intramuscular interferon beta-1a 15 micrograms once a week and the second group received no disease-modifying therapy. RESULTS: The patients were followed for four years. There was no significant side effect and none of the treated patients discontinued the drug. There were significant differences between two groups regarding relapse rates (p = 0.04), disability progression (p = 0.01), and new T2 lesions (p = 0.006). CONCLUSION: Treatment with interferon beta-1a is well tolerated for a long period of time and may be effective in substandard doses in early onset multiple sclerosis.

[Diffuse cutaneous vasculitis disclosing acute lymphoblastic leukemia]. / Vascularite cutanée diffuse révélatrice d'une leucémie lymphoblastique aigüe.

Biopsy of skin for etiologic evaluation of generalized erythematous eruptions in a 4 1/2 years old child, starting four months ago, led to diagnosis of acute lymphoblastic leukemia. Leukocyte counts five and eight weeks and four months after appearance of eruptions were normal and no blasts were found. A leukocyte count performed simultaneously with biopsy of skin also showed few (less than 10%) blasts. Histologic examination of skin revealed two types of pathologic lesions: a perivascular cuffing of lymphoblasts and a leukocytoclastic type of small vessel vasculitis in other parts. This type of vasculitis which have been reported in association with chronic lymphocytic and hairy cell leukemias, is uncommon in acute lymphoblastic leukemia.

[Acute encephalopathy and recurrent hepatic steatosis with normal long and medium chain fatty acyl-CoA-dehydrogenase activity]. / Encéphalopathie aiguë et stéatose hépatique récurrentes avec activité normale de l'acyl-CoA-déhydrogénase des acides gras à chaîne longue et moyenne.

A boy suffering from recurrent episodes of acute encephalopathy and hepatic steatosis died at 40 months of age. The symptoms started when he was 13 months old and he appeared completely normal in the intervals. Pertinent biologic findings were as follows: slight labile hypoglycemia and hyperammonemia having no direct correlation with neurologic derangement, no elevation of ammonia levels in loading tests, complete failure to generate ketones and the absence of organic aciduria during a fast, normal plasma carnitine levels and normal activity of long and medium chain acyl-CoA-dehydrogenase in skin fibroblasts. Pertinent autopsy findings were marked steatosis of liver and renal tubular cells with many foamy histiocytes in bone marrow. An error in metabolic pathways, particularly a derangement in lipid metabolism, was considered.

[Coexistence of late spondyloepiphyseal dysplasia and congenital megaloblastic anemia with proteinuria in the same family]. / Coexistence d'une dysplasie spondylo-épiphysaire tardive et d'une anémie mégaloblastique congénitale avec protéinurie dans la même famille.

A case of spondyloepiphyseal dysplasia tarda was noted in a dwarf (130 cm tall) 18 years old boy associated with congenital megaloblastic anemia and proteinuria. His two sisters and a cousin are also suffering from similar hematologic disorder. One of his brothers, 145 cm tall, is also involved by spondyloepiphyseal dysplasia, but there is no known hematologic abnormalities. Review of family history revealed that two aunts from mother's side were deceased in adulthood following a chronic anemic disease. The findings in this anemia are compatible with Imerslund-Grâsbech syndrome and coexistence of these two rare genetic disorders in a single family has not been reported previously.