NEURONS CULTURED ON GaN AND IS ASSOCIATED WITH SYNAPSIN I AND MAP2 EXPRESSION

2008 ◽  
Vol 20 (02) ◽  
pp. 75-82 ◽  
Author(s):  
Chi-Ruei Chen ◽  
Tai-Horng Young
Keyword(s):  
Microelectrode Array ◽  
Synapsin I ◽  
Granule Neurons ◽  
Ldh Assay ◽  
Electric Signals ◽  
First Time ◽  
Neuronal Adhesion ◽  
Very High ◽  
Better Than

In this work, the behaviors of cerebellar granule neurons prepared from 7-day-old Wistar rats on GaN, GaAs, and silicon were investigated. We believe that this is the first time that the GaN has been used as a substrate for neuron cultures to examine its effect on cell response in vitro. The GaN surface structure and its relationship with cells were examined by scanning electron microscopy (SEM), immunofluorescence lactate dehydrogenase (LDH). Compared with silicon used for most neural chips, neurons seeded on GaN were able to form an extensive neuritic network and expressed very high levels of synapsin I coincident with the neurite outgrowth. LDH assay indicated that GaN improve neuron survival better than silicon and GaAs. Between in seven-day and day 15-cultured neurons, these results are consistent with the influence of GaN, in the regulation of neuronal adhesion, neuritic plasticity and survival, within in vitro. The favorable biocompatibility characteristics of GaN can be used to measure electric signals from networks of neuronal cells in culture to make it a possible candidate for use in a microelectrode array.

scholarly journals Immunoglobulin Attenuates Streptokinase-Mediated Virulence inStreptococcus dysgalactiae Subspeciesequisimilis Necrotizing Fasciitis

2017 ◽  
Vol 217 (2) ◽  
pp. 270-279 ◽  
Author(s):  
Federica Andreoni ◽  
Fabio Ugolini ◽  
Nadia Keller ◽  
Andrina Neff ◽  
Victor Nizet ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Mouse Model ◽  
Necrotizing Fasciitis ◽  
Protective Role ◽  
Specific Antibodies ◽  
Blocking Antibodies ◽  
First Time ◽  
Very High

Abstract Background Necrotizing fasciitis (NF) retains a very high mortality rate despite prompt and adequate antibiotic treatment and surgical debridement. Necrotizing fasciitis has recently been associated withStreptococcus dysgalactiae subspeciesequisimilis (SDSE). Methods We investigated the causes of a very severe clinical manifestation of SDSE-NF by assessing both host and pathogen factors. Results We found a lack of streptokinase-function blocking antibodies in the patient resulting in increased streptokinase-mediated fibrinolysis and bacterial spread. At the same time, the clinical SDSE isolate produced very high levels of streptokinase. Exogenous immunoglobulin Gs (ex-IgGs) efficiently blocked streptokinase-mediated fibrinolysis in vitro, indicating a protective role against the action of streptokinase. In vivo, SDSE infection severity was also attenuated by ex-IgGs in a NF mouse model. Conclusions These findings illustrate for the first time that the lack of specific antibodies against streptococcal virulence factors, such as streptokinase, may contribute to NF disease severity. This can be counteracted by ex-IgGs.

scholarly journals Wild Mushrooms in Nepal: Some Potential Candidates as Antioxidant and ACE-Inhibition Sources

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Tran Hai Bang ◽  
Hiroto Suhara ◽  
Katsumi Doi ◽  
Hiroya Ishikawa ◽  
Katsuya Fukami ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Biological Activities ◽  
Ace Inhibition ◽  
Promising Candidate ◽  
Phenolic Contents ◽  
High Antioxidant Activity ◽  
First Time ◽  
Ganoderma Lingzhi ◽  
Very High

Twenty-nine mushrooms collected in the mountainous areas of Nepal were analyzed for antioxidant activity by different methods, including Folin-Ciocalteu, ORAC, ABTS, and DPPH assays. Intracellular H2O2-scavenging activity was also performed on HaCaT cells. The results showed that phenolic compounds are the main antioxidant of the mushrooms. Among studied samples,Inonotus andersonii, andPhellinus gilvusexhibited very high antioxidant activity with the phenolic contents up to 310.8 and 258.7 mg GAE/g extracts, respectively. The H2O2-scavenging assay on cells also revealed the potential of these mushrooms in the prevention of oxidative stress. In term of ACE-inhibition, results showed thatPhlebia tremellosawould be a novel and promising candidate for antihypertensive studies. This mushroom exhibited even higherin vitroACE-inhibition activity thanGanoderma lingzhi, with the IC50values of the two mushrooms being 32 μg/mL and 2 μg/mL, respectively. This is the first time biological activities of mushrooms collected in Nepal were reported. Information from this study should be a valuable reference for future studies on antioxidant and ACE-inhibitory activities of mushrooms.

EXCELLENT ELECTROCHEMICAL BEHAVIOR OF LiMn2O4 IN AQUEOUS ELECTROLYTE

2010 ◽  
Vol 03 (03) ◽  
pp. 151-154 ◽  
Author(s):  
QUTING QU ◽  
GAOJUN WANG ◽  
LILI LIU ◽  
SSHU TIAN ◽  
YI SHI ◽  
...  
Keyword(s):  
Current Density ◽  
Electrochemical Behavior ◽  
Lithium Battery ◽  
Aqueous Electrolyte ◽  
Rate Capability ◽  
Reversible Capacity ◽  
Reversible Redox ◽  
First Time ◽  
Very High ◽  
Better Than

LiMn 2 O 4 was prepared by a solid-state reaction, and for the first time its electrochemical behavior in the organic and aqueous electrolytes were compared. Since the host structure is the same, the intercalation and deintercalation behavior does not change, and the diffusion coefficient of Li + ions are in the same range. However, due to much higher ionic conductivity of the aqueous electrolyte, its reversible redox behavior at high scan rate is much better than in the organic electrolyte. The reversible capacity in the aqueous electrolyte is 85 mAh ⋅ g-1 at the current density of 50 mA ⋅ g-1, and 22 mAh ⋅ g-1 (26% of the normal capacity) when the current density is up to 10,000 mA ⋅ g-1 (118 C). This shows that aqueous rechargeable lithium battery (ARLB) have very high-power density or excellent rate capability, and good cycling behavior.

scholarly journals Isolation of intact megakaryocytes from guinea pig femoral marrow. Successful harvest made possible with inhibitions of platelet aggregation; enrichment achieved with a two-step separation technique.

1976 ◽  
Vol 69 (1) ◽  
pp. 159-172 ◽  
Author(s):  
R F Levine ◽  
M E Fedorko
Keyword(s):  
Guinea Pig ◽  
Gradient Centrifugation ◽  
Velocity Sedimentation ◽  
High Yield ◽  
Equilibrium Density ◽  
Large Size ◽  
Membrane Topography ◽  
First Time ◽  
Better Than

Methods have been devised to harvest megakaryocytes from guinea pig femoral marrow and to isolate them in high yield. When marrow tissue was disaggregated the megakaryocytes underwent degenerative changes characterized by the loss of cytoplasmic granules and alterations in membrane topography, similar to the changes seen in aggregating platelets. These morphologic changes were interpreted to mean that megakaryocytes possessed functional attributes of platelets. The use of agents which inhibit platelt aggregation (0.38% sodium citrate. 10(-3) M adenosine, and 2 x 10(-3) M theophylline) in a medium free of bivalent cations prevented these changes. This solution resulted in both an excellent morphologic preservation and a significantly increased recovery of megakaryocytes from marrow tissue. A two-step purification of the intact megakaryocytes was carried out on the basis of their low density and large size, with equilibrium density gradient centrifugation followed by velocity sedimentation. This sequence gave approximately a 100-fold enrichment of megakaryocytes, significantly better than that achieved with either method alone. These techniques for harvesting and concentrating megakaryocytes make it possible for the first time to study megakaryocytes in vitro.

Vesicular Lipid Nanoparticles (Liposomes) for the Treatment of Medical Device Infections

2011 ◽  
Vol 1316 ◽  
Author(s):  
Erik Taylor ◽  
Anubhav Kaviratna ◽  
Rinti Banerjee ◽  
Thomas J. Webster
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Lipid Nanoparticles ◽  
In Vitro Assay ◽  
Silver Sulfadiazine ◽  
Human Pathogens ◽  
Vitro Assay ◽  
First Time ◽  
Better Than

AbstractLiposomes (a phospholipid bi-layer which can be formulated to contain drugs or other reagents) composed of endogenous phospholipid dipalmitoylphosphatidylcholine (DPPC) in combination with dioleoylphosphatidylethanolamine (DOPE), lauric acid, and silver sulfadiazine were made into vesicular nanoparticles in this study using an optimized extrusion technique. Liposomes were then tested for antibacterial activity against a range of bacteria species including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Bacillus subtilis (all are relevant human pathogens known to infect implants) and were also challenged to prevent the growth of adherent biofilms (a robust slimy extracellular matrix) through an in vitro assay relevant to device related infections. It was found that all liposomes reduced bacterial growth, and, most importantly, liposomes containing DPPC and DOPE reduced biofilm formation better than the commercially available antibiotic silver sulfadiazine. These results indicated for the first time that such liposomes might be a better approach to prevent device related infections.

scholarly journals Ephemeral states in protein folding under force captured with a novel magnetic tweezers design

2018 ◽  
Author(s):  
Rafael Tapia-Rojo ◽  
Edward C. Eckels ◽  
Julio M. Fernandez
Keyword(s):  
Magnetic Field ◽  
Molten Globule ◽  
Magnetic Tweezers ◽  
Protein L ◽  
High Frequencies ◽  
Electric Signals ◽  
Very High Frequencies ◽  
First Time ◽  
The Magnetic Field ◽  
Very High

AbstractMagnetic tape heads are ubiquitously used to read and record on magnetic tapes in technologies as diverse as old VHS tapes, modern hard drive disks, or magnetic bands on credit cards. Their design highlights the ability to convert electric signals into fluctuations of the magnetic field at very high frequencies, which is essential for the high density storage demanded nowadays. Here, we twist this conventional use of tape heads to implement one in a new magnetic tweezers design, which offers the unique capability of changing the force with a bandwidth of ~ 10 kHz. We calibrate our instrument by developing an analytical expression that predicts the magnetic force acting on a superparamagnetic bead based on the Karlqvist approximation of the magnetic field created by a tape head. This theory is validated by measuring the force dependence of protein L unfolding/folding step sizes, and the folding properties of the R3 talin domain. We demonstrate the potential of our instrument by carrying out millisecond-long quenches to capture the formation of the ephemeral molten globule state in protein L, which has never been observed before. Our instrument provides for the first time the capability of interrogating individual molecules under fast-changing forces with a control and resolution below a fraction of a pN, opening a range of novel force spectroscopy protocols to study protein dynamics under force.

Daunorubicin and Platelet Function

1981 ◽  
Vol 45 (01) ◽  
pp. 038-042 ◽  
Author(s):  
M E Pogliani ◽  
R Fantasia ◽  
G Lambertenghi-Deliliers ◽  
E Cofrancesco
Keyword(s):  
Electron Microscope ◽  
Cellular Membrane ◽  
Hemorrhagic Diathesis ◽  
Clot Retraction ◽  
Freezing And Thawing ◽  
Platelet Factor ◽  
High Doses ◽  
Very High ◽  
Platelet Functions

SummaryThe influence of Daunorubicin on some platelet functions in vitro was investigated, using different concentrations of the drug (0.01-0.02-0.04 μg/ml). Daunorubicin was shown to inhibit Collagen and Thrombin induced platelet aggregation and the intensity of inhibition depended on both drug concentration and the time of preincubation.Daunorubicin was also shown to inhibit the release reaction, the platelet prostaglandin pathway and the availability platelet factor 3; the drug at concentrations for clinical use does not damage the platelet membrane, as is the case with the freezing and thawing test, in platelet uptake of 14C-serotonin and as confirmed by the electron microscope. When very high doses (0.16 mg) of Daunorubicin are used, lysis of the platelets can be observed and this is confirmed under the electron microscope by the presence of empty platelets with fractures at the level of the cytoplasmic membrane.Finally, Daunorubicin causes irreversible inhibition of reptilase clot-retraction, even if this is less severe than with Vincristine. Working with gel-filtered platelets, it would appear that the inhibition exercised by the drug on platelet reactions is not caused through modifications in Ca++ metabolism.The authors suggest that Daunorubicin, at the dosages used clinically, induces in vitro thrombocytopathy without damaging the cellular membrane as confirmed by the electron microscope.This impairment of platelet functions could play a part in hemorrhagic diathesis observed during Daunorubicin therapy.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Controlled Release of Metformin Hydrochloride I. In vitro Release from Physical Mixture Containing Xanthan Gum as Hydrophilic Rate Retarding Polymer

1970 ◽  
Vol 4 (1) ◽  
Author(s):  
Mashkura Ashrafi ◽  
Jakir Ahmed Chowdhury ◽  
Md Selim Reza
Keyword(s):  
Controlled Release ◽  
Xanthan Gum ◽  
In Vitro Release ◽  
Correlation Coefficients ◽  
High Ratio ◽  
Water Soluble ◽  
Metformin Hydrochloride ◽  
Model Drug ◽  
Very High

Capsules of different formulations were prepared by using a hydrophilic polymer, xanthan gum and a filler Ludipress. Metformin hydrochloride, which is an anti-diabetic agent, was used as a model drug here with the aim to formulate sustained release capsules. In the first 6 formulations, metformin hydrochloride and xanthan gum were used in different ratio. Later, Ludipress was added to the formulations in a percentage of 8% to 41%. The total procedure was carried out by physical mixing of the ingredients and filling in capsule shells of size ‘1’. As metformin hydrochloride is a highly water soluble drug, the dissolution test was done in 250 ml distilled water in a thermal shaker (Memmert) with a shaking speed of 50 rpm at 370C &plusmn 0.50C for 6 hours. After the dissolution, the data were treated with different kinetic models. The results found from the graphs and data show that the formulations follow the Higuchian release pattern as they showed correlation coefficients greater than 0.99 and the sustaining effect of the formulations was very high when the xanthan gum was used in a very high ratio with the drug. It was also investigated that the Ludipress extended the sustaining effect of the formulation to some extent. But after a certain period, Ludipress did not show any significant effect as the pores made by the xanthan gum network were already blocked. It is found here that when the metformin hydrochloride and the xanthan gum ratio was 1:1, showed a high percentage of drug release, i.e. 91.80% of drug was released after 6 hours. But With a xanthan gum and metformin hydrochloride ratio of 6:1, a very slow release of the drug was obtained. Only 66.68% of the drug was released after 6 hours. The percent loading in this case was 14%. Again, when Ludipress was used in high ratio, it was found to retard the release rate more prominently. Key words: Metformin Hydrochloride, Xanthan Gum, Controlled release capsule Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

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