Kinetics of Oxygen Reduction in Aprotic Li-O2 Cells: A Model-Based Study

A comprehensive and general kinetic model is developed for the oxygen reduction reaction in aprotic Li-O2 cells. The model is based on the competitive uptake of lithium superoxide by the surface and solution. A demonstrative kinetic study is provided to demystify the origin of curvature in Tafel plots as well as the current dependency and aberrant diversity of the nature and morphology of discharge products in these systems. Our results are general and extend to any system where solubilization of superoxide is favored, such as where phase-transfer catalysts play an important role.

In-vitro comparison of instrumentation time and cleaning capacity between endodontic handpiece and manual preparation techniques in primary molar teeth

AIM

The aim of this study was to evaluate and compare the cleaning ability and instrumentation time of manual method and use of endodontic handpiece for preparation of primary molar teeth.

METHODS

Forty primary teeth canals were used in this experimental study. Access cavities were prepared and India ink was injected into the canals. The samples were divided into three groups according to the preparation technique. In the first group the root canals were manually instrumented by k_files. Endodontic handpiece (TEP-ER10, NSK, Japan) were used for canal preparation in the second group and the samples in the third group (control) were not instrumented. After preparing the canal, the teeth were cleared with methyl salicylate and the removal of India ink was measured in the cervical, middle and apical thirds. The instrumentation time was transcribed by chronometer. Statistical analysis was performed using Mann-Whitney and t-test.

RESULTS

There was no significant difference in cleaning capacity between the two techniques, but results of the first and second group differ from those of the control group. In fact, time taken for preparation was significantly shorter with endodontic handpiece system.

CONCLUSION

Seen the shorter working time of endodontic handpiece and the similar cleaning ability of the two techniques, the application of the endodontic handpiece is recommended for preparation of deciduous root canals during pulpectomy.

Synergistic effect of intravenous immunoglobulins and iodinated contrast media on renal function

Acute renal failure is one of the side effects while using intravenous immunoglobulins. This complication is also observed with iodinated contrast media. Herein, we describe a patient with acute renal failure who received intravenous immunoglobulins and iodinated contrast media concomitantly. Both drugs are responsible for osmotic nephrosis. The same effect on renal cells may explain a synergistic effect on renal function.

The effect of participatory community-based diabetes cares on the control of diabetes and its risk factors in western suburb of Yasouj, Iran

This study aimed to investigate whether a community-based participatory diabetes care program could efficiently improve diabetic care and reduce its risk factors. To induce a participatory approach, a local group was established in partnership with academics, local leaders, health providers and public representatives. The group conducted community needs assessment and priority setting process. Diabetes was identified as the first priority health problem in this area. A total of 2569 30- to 65-year-old residents were screened for diabetes and 405 of them took part in a 13-week nutrition education and physical exercise intervention. Out of 1336 high-risk individuals, 17% had fasting blood sugar (FBS) ≥126 mg/dl and 13.5% with FBS between 110 and 125 mg/dl. Percentages of participants with triglycerides (TG) ≥150 mg/dl and cholesterol ≥200 mg/dl were 33.8% and 23.5%, respectively. After completion of the intervention, the mean FBS, HbA1C, TG and cholesterol were decreased significantly. Although systolic and diastolic blood pressure and body mass index were decreased too, the differences were not statistically significant. The mean physical activity increased and consumption of fried foods and saturated oil decreased significantly. The results suggest that participatory community-based care could be a feasible model for control of diabetes and its risk factors.

Stem cells therapy for retinal degeneration

Stem cell therapy is widely considered as a therapeutic approach for retinal degeneration. Retinal injury results in permanent visual disturbance or blindness. Repair of such damage by stem cells is one of the most feasible types of central nervous system repair. In this review, we consider how stem cells might be optimized for use as donor cells. We discuss the benefits of stem cells for transplantation in retinal degenerative disease. A wide range of stem cells from different sources is being investigated for the treatment of retinal degeneration. This study reviews the recent and old achievements about stem cells for retinal repair.

Development of beta-tricalcium phosphate/sol-gel derived bioactive glass composites: physical, mechanical, and in vitro biological evaluations

In this study, composites of beta-tricalcium phosphate (beta-TCP) and sol gel derived bioactive glass (10, 25, and 40 wt %) based on the SiO(2)-CaO-MgO-P(2)O(5) system were prepared and sintered at 1000-1200 degrees C. The mechanical properties were investigated by measuring bending strength, Vickers hardness and fracture toughness. Structural properties were evaluated by XRD and SEM analysis, and the biological properties were studied by soaking the samples in simulated body fluid (SBF) and in contact with osteoblastic cell for viability assay. When the samples were sintered at 1200 degrees C, the mechanical strength increased, up to 34%, by increasing the amount of bioactive glass phase. In contrast, it decreased when the samples were sintered at 1000 and 1100 degrees C. The results showed that the strength could be improved up to 56% when more firing period was used. Incorporation of the bioactive glass phase into beta-TCP increased the microhardness but did not significantly change the fracture toughness. Phase analysis revealed that beta-TCP or magnesium-substituted beta-TCP was the main crystalline phase of the composites beside some calcium silicate crystallized in the bioactive glass phase. Plenty precipitation of calcium phosphate layer onto the surfaces of the beta-TCP/bioactive glass composites soaked in SBF indicated superior bioactivity of these materials compared to pure beta-TCP without any precipitation. The ability of beta-TCP/bioactive glass composites to support the growth of human osteoblastic cells was considerably better than that of pure beta-TCP. These results may be used to indicate which compositions and processing conditions can provide appropriate materials for hard tissue regeneration.

Composite bone substitute materials based on beta-tricalcium phosphate and magnesium-containing sol-gel derived bioactive glass

In the present study, bioceramic composites with improved mechanical and biological properties were synthesized by sintering mixtures of beta-tricalcium phosphate and SiO(2)-CaO-MgO-P(2)O(5) sol-gel derived bioactive glass at 1000-1200 degrees C. The physical, mechanical, structural and biological properties of the composites were evaluated by appropriate experiments such as microhardness, bending strength, XRD, SEM and MTT. The results showed that 1000 and 1100 degrees C were not appropriate temperatures for sintering the composites and in contrast, the microhardness, bending strength and bulk density significantly increased by increasing in quantity of bioglass phase when the samples were sintered at 1200 degrees C. No significant difference was found between the fracture toughness of the composites and pure beta-tricalcium phosphate. beta-tricalcium phosphate was structurally stable up to 1200 degrees C and did not transform to its alpha form even in the presence of the bioglass phase but migration of magnesium cations from the glass composition into its lattice structure was found by right-shift in XRD patterns, especially when the composite contained higher amount of bioglass component. Calcium silicate was also crystallized in the composition of the composites, which was more detectable in higher sintering temperatures. The results of the MTT test showed that proliferation of human osteosarcoma cells on the composites was considerably better than that of pure beta-TCP.

Retinoic acid stimulate differentiation of hippocampal stem cells into opsin expressing cells in vitro

The results of several studies have demonstrated that cell differentiation influenced by derivatives of retinoic acid. To determine whether retinoic acid mediate the differentiation of neural stem cells we treated dissociated hippocampal stem cells with different concentrations of all trans or 9-cis retinoic acid and analyzed the effects on cell fate by specific monoclonal antibody for photoreceptors. Addition of exogenous retinoic acid caused a dose dependent specific in the elevation of the cell number that developed as photoreceptors in culture. Also results ofimmunohistochemical studies using monoclonal antibody demonstrated that the primary effect ofretinoic acid was to influence progenitor cells the developed as mature and immature photoreceptors. These results suggest that retinoic acid may play an important effect in the normal development of photoreceptor cells in vitro.

Alterations of inducible and constitutive nitric oxide synthase after hippocampal injury in rats

The aim of this study was to study the changes of inducible and constitutive Nitric Oxide Synthase (NOS) after brain injury. In order to brain injury 42 wistar rats were submitted and divided in 7 groups. Nitric oxide synthase activities were assayed at different times after injury. Present results showed that a significant increase of iNOS and cNOS activity 8 h after lesion. In conclusion, both isoformes of NOS increase at different time after brain injury.

Onychomadesis in a patient with immunoglobulin class switch recombination deficiency

Immunoglobulin class switch recombination deficiencies (Ig CSR deficiencies) or Hyper IgM syndromes (HIGM) are a group of primary immunodeficiency diseases, characterized by defective CD40 signaling of B cells, resulting in reduced CSR and somatic hypermutation. The affected patients are characterized by low serum levels of IgG and IgA, and normal or elevated levels of IgM, which lead to an increased susceptibility to infections. We describe a 3 year-old boy with frequent bacterial infections of the skin and respiratory tract, mucosal ulcers, and diarrhea. He experienced onychomadesis of both fingernails and toenails during a recent bacterial infection. Quantitative immunoglobulin measurements revealed high levels of serum IgM and very low levels of IgG, IgA, and IgE. Clinical and immunologic studies supported the diagnosis of HIGM. Exclusion of CD40L, CD40, AID and UNG genes by molecular analysis in this patient may suggest a new form of selective CSR deficiency.

Carnation mottle virus, an important viral agent infecting carnation cut-flower crops in Mahallat of Iran

One of the most important cut-flower crops grown worldwide on commercial scale is Carnation (Dianthus caryophyllus L.). It's the main production of Mahallat where is one of the most important ornamental plants production centers of Iran. Infection of carnation with pathogens Like viral agents causes economic losses in carnation cut-flower crop. One of the viral agents of this flower is Carnation mottle virus (CarMV) which is the type member of genus Carmovirus and belongs to the Tombusviridae family. It is naturally transmitted by grafting and contacting between plants. Although its infection lead to mild symptims, it weakens the plant to infection by other pathogens. The carnation greenhouses of Mahallat were visited during 2008 January to April and 100 samples with mild mosaic symptom were collected and tested by DAS-ELISA using CarMV specific polyclonal antibody. The results showed that 75% of samples wrere infected with this virus. Mechanical inocubation of Chenopodium quinoa, C. amaranticolor and Spinacea oleracea with extracted crude sap of CarMV infected carnation Leaves in phosphate buffer (pH, 7) resulted in appearance of chlorotic and necrotic local lesions on inoculated leaves 4-7 days after incubation. The virus was partially purified using C. amaranticolor locally symptomatic leaves. Total soluble proteins were extracted from healthy and CarMV infected C. amaranticolor plants and beside partially purified preparation electrophoresed through 15% poly acrylamide get according to SDS-PAGE standard procedure. Protein bands were electroblotted onto nitrocelluse membrane and incubated with CarMV polyclonal during western immunoblot analysis according to standard method. The result revealed a distinc protein band with Mr of 35.5 kDa in total protein preparation of infected plant and viral partial pure preparation, without any reaction in those of healthy plant. RT-PCR carried out using total RNA extracted from infected plant by Rneasy Plant Mini Kit (Qiagen)and a pair of primers, CPu, CPd, corresponding to the flanking region of the virus CP resulted in amplification of a DNA fragment in expected size around 1 kbp.

Serotonergic and noradrenergic lesions suppress the enhancing effect of maternal exercise during pregnancy on learning and memory in rat pups

The beneficial effects of exercise on learning and memory are well documented but the effects of prenatal exposure to maternal exercise on offspring are not clear yet. Using a two-trial-per-day Morris water maze for five consecutive days, succeeded by a probe trial 2 days later we showed that maternal voluntary exercise (wheel running) by pregnant rats increased the acquisition phase of the pups' learning. Maternal forced swimming by pregnant rats increased both acquisition and retention phases of the pups' learning. Also we found that the rat pups whose mother was submitted to forced-swimming during pregnancy had significantly higher brain, liver, heart and kidney weights compared with their sedentary counterparts. On the other hand we estimated the cell number of different regions of the hippocampus in the rat pups. We found that both exercise models during pregnancy increased the cell number in cornus ammonis subregion 1 (CA1) and dentate gyrus of the hippocampus in rat pups. To determine the role that noradrenergic and serotonergic neurotransmission and N-methyl-D-aspartate (NMDA) receptors hold in mediation of the maternal exercise in offspring, we used N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4), p-chloroamphetamine (PCA) and MK-801 to eliminate or block the above systems, respectively. Blocking the NMDA receptors, significantly abolished learning and memory in rat pups from all three experimental groups. Elimination of noradrenergic or serotonergic input did not significantly attenuate the learning and memory in rat pups whose mothers were sedentary, while it significantly reversed the positive effects of maternal exercise during pregnancy on rat pups' learning and memory. The presented results suggest that noradrenergic and serotonergic systems in offspring brain seem to have a crucial specific role in mediating the effects of maternal physical activity during pregnancy on rat pups' cognitive function in both models of voluntary and forced exercise.

Sudden unilateral blindness in a girl with Kawasaki disease

This article describes a 9-year-old girl with clinical and laboratory features of Kawasaki disease. On day 7 of her febrile illness, she developed sudden loss of vision in the right eye. Visual acuity was no light perception. Dilated funduscopy showed diffuse intense retinal whitening, narrowing retinal arterioles, and a pale swollen disk-but no cherry-red spot. These findings suggested ophthalmic artery obstruction. Kawasaki disease can be sight-threatening.

Hair loss as a sign of Kawasaki disease

Kawasaki disease is a multi system disorder with varying clinical expressions. This disease is an acute systemic vasculitis of unknown etiology that has recently recognized as a leading cause of acquired heart disease in children of many developed countries. We describe an unusual instance of hair loss in a patient with Kawasaki disease. A 26 months old boy developed prolonged high fever, bilateral conjunctival infection, arthralgia and erythromatosis skin rash. He was admitted to the hospital with the diagnosis of Kawasaki disease. Laboratory results included an erythrocyte sedimentation rate (ESR) above 100 and platelet count > 1000,000. The patient developed acute and unprovoked scalp hair loss. He was treated with intravenous immunoglobulin (IVIG) 2 g/kg and aspirin 100 mg/kg/day with complete improvement of signs and symptoms. This report documents hair loss as an uncommon presentation of Kawasaki disease.