Immobilization of gold nanoparticles with rhodamine to enhance the fluorescence resonance energy transfer between quantum dots and rhodamine; new method for downstream sensing of infectious bursal disease virus

Infectious bursal disease virus is a causative agent of one of the most important disease which causes frequent tragic disaster in the poultry industry all over the world. Therefore, in the present study a new fluorescence resonance energy transfer-based technique was developed to detect VP2 gene of infectious bursal disease virus using two oligonucleotide probes labeled with quantum dots and rhodamine- immobilized gold nanoparticles (AuNPs-Rh). Quantum dots labeled with an amino-modified first oligonucleotide, and AuNPs-Rh labeled with thiol-modified second oligonucleotides were added to the DNA targets upon which hybridization occurred. In the presence of target the AuNPs-Rh will be located in the vicinity of the quantum dots and leads to the fluorescence resonance energy transfer to be occurred and subsequently the fluorescence intensity of quantum dots was stimulated. The immobilization of rhodamine to the surface of AuNPs increased the fluorescence intensity of rhodamine. The maximum fluorescence resonance energy transfer efficiency for the developed sensor is monitored at a quantum dots-P_A/AuNPs-Rh-P_T molar ratio of 1:10. Moreover, the feasibility of the developed nanobiosensor was demonstrated by the detection of a synthetic 49-mer nucleotide derived from infectious bursal disease virus and the limit of detection was estimated as 3 × 10^-8 M. The developed DNA detection scheme is a simple, rapid and efficient technique which does not need excessive washing and separation steps.

Physical and antimicrobial properties of starch-carboxy methyl cellulose film containing rosemary essential oils encapsulated in chitosan nanogel

This study was set to prepare a new active film by using a biodegradable bio-based source, i.e., corn starch. To achieve that, benzoic acid (BA) and chitosan (CS) were covalently bound and CS-BA nanogel was then obtained using self-assembly method. Subsequently, rosemary essential oil (REO) was encapsulated in CS-BA nanogel. Finally, REO in both free and encapsulated forms were incorporated in starch-carboxy methyl cellulose (CMC) films and their physical, mechanical and antimicrobial properties were studied. The films incorporating CS-BA nanogel had a higher water vapor permeability compared with the films containing REO. Moreover, film containing 0.2% CS-BA nanogel had the highest transparency and tensile strength. The REO and nanogel alone had inhibitory effects against Staphylococcus aureus (S. aureus) and by encapsulation, the inhibitory effect of REO was increased. By encapsulating REO in nanogel, both immediately (REO) and gradual (Nanogel) antimicrobial effect against S. aureus in the starch-CMC suspensions were obtained.

Detection of Citrus tristeza virus by using fluorescence resonance energy transfer-based biosensor

Due to the low titer or uneven distribution of Citrus tristeza virus (CTV) in field samples, detection of CTV by using conventional detection techniques may be difficult. Therefore, in the present work, the cadmium-telluride quantum dots (QDs) was conjugated with a specific antibody against coat protein (CP) of CTV, and the CP were immobilized on the surface of gold nanoparticles (AuNPs) to develop a specific and sensitive fluorescence resonance energy transfer (FRET)-based nanobiosensor for detecting CTV. The maximum FRET efficiency for the developed nano-biosensor was observed at 60% in AuNPs-CP/QDs-Ab ratio of 1:8.5. The designed system showed higher sensitivity and specificity over enzyme linked immunosorbent assay (ELISA) with a limit of detection of 0.13μgmL(-1) and 93% and 94% sensitivity and specificity, respectively. As designed sensor is rapid, sensitive, specific and efficient in detecting CTV, this could be envisioned for diagnostic applications, surveillance and plant certification program.

Chitosan-myristate nanogel as an artificial chaperone protects neuroserpin from misfolding

Background:

Molecular chaperon-like activity for protein refolding was studied using nanogel chitosan-myristic acid (CMA) and the protein neuroserpin (NS), a member of the serine proteinase inhibitor superfamily (serpin).

Materials and Methods:

Recombinant his-tag fusion NS was expressed in Escherichia coli. For confirmation of refolding of the purified NS, structural analysis was performed by circular dichroism and spectrofluorometric along with its inhibitory activity, which was assayed by single-chain tissue plasminogen activator. For evaluating NS aggregation during preparation, the samples were separated on a 7.5% (w/v) nondenaturing polyacrylamide gel electrophoresis. MA and chitosan covalently join together by the formation of amide linkages through the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-mediated reaction. The morphology and size of the prepared CM nanogel were characterized by transmission electron microscopy and scanning electron microscopy.

Results:

Heating at different temperatures (25°C, 37°C, 45°C, 65°C, 80°C) results in a further rise in β-structures accompanied by a fall of helices and no significant change in random coils. Structural changes in NS in the presence of CMA nanogel were less than that in the absence of CMA nanogel. Mater nanogel effectively prevented aggregation of NS during temperature induced protein refolding by the addition of cyclodextrins. The nanogel activity resembled the host-guest chaperon activity.

Conclusion:

These conditions, called conformational disorders, include Alzheimer's, Parkinson's, Huntington's disease, the transmissible spongiform encephalopathies, prion diseases, and dementia. Nanogels can be useful in recovery of the structural normality of proteins in these diseases.

Collagen-chitosan 3-D nano-scaffolds effects on macrophage phagocytosis and pro-inflammatory cytokine release

Macrophages are effector cells in the innate and adaptive immune systems and in situ exist within three-dimensional (3-D) microenvironments. As there has been an increase in interest in the use of 3-D scaffolds to mimic natural microenvironments in vitro, this study examined the impact on cultured mice peritoneal macrophages using standard 2-D plates as compared to 3-D collagen-chitosan scaffolds. Here, 2-D and 3-D cultured macrophages were evaluated for responses to lipopolysaccharide (LPS), dexamethasone (Dex), BSA (bovine serum albumin), safranal (herbal component isolated from safranal [Saf]) and Alyssum homolocarpum mucilage (A. muc: mixed herbal components). After treatments, cultured macrophages were evaluated for viability, phagocytic activity and release of tumor necrosis factor (TNF)-α and interleukin (IL)-1β pro-inflammatory cytokines. Comparison of 2-D vs 3-D cultures showed that use of either system - with or without any exogenous agent - had no effect on cell viability. In the case of cell function, macrophages cultured on scaffolds had increases in phagocytic activity relative to that by cells on 2-D plates. In general, the test herbal components Saf and A. muc. had more impact than any of the other exogenous agents on nanoparticle uptake. With respect to production of TNFα and IL-1β, compared to the 2-D cells, scaffold cells tended to have significantly different levels of production of each cytokine, with the effect varying (higher or lower) depending on the test agent used. However, unlike with particle uptake, here, while Saf and A. muc. led to significantly greater levels of cytokine formation by the 3-D culture cells vs that by the 2-D plate cells, there was no net effect (stimulatory) vs control cultures. These results illustrated that collagen-chitosan scaffolds could provide a suitable 3-D microenvironment for macrophage phagocytosis and could also impact on the formation of pro-inflammatory cytokines.

Genotoxic Damage to Glioblastoma Cells Treated with 6 MV X-Radiation in The Presence or Absence of Methoxy Estradiol, IUDR or Topotecan

Objective

To explore the cumulative genotoxic damage to glioblastoma (GBM) cells, grown as multicellular spheroids, following exposure to 6 MV X-rays (2 Gy, 22 Gy) with or without, 2- methoxy estradiol (2ME2), iododeoxyuridine (IUDR) or topotecan (TPT), using the Picogreen assay.

Materials and Methods

The U87MG cells cultured as spheroids were treated with 6 MV X-ray using linear accelerator. Specimens were divided into five groups and irradiated using X-ray giving the dose of 2 Gy after sequentially incubated with one of the following three drug combinations: TPT, 2-ME2/TPT, IUDR/TPT or 2ME2/IUDR/ TPT. One specimen was used as the irradiated only sample (R). The last group was also irradiated with total dose of 22 Gy (each time 2 Gy) of 6 MV X-ray in 11 fractions and treated for three times. DNA damage was evaluated using the Picogreen method in the experimental study.

Results

R/TPT treated group had more DNA damage [double strand break (DSB)/single strand break (SSB)] compared with the untreated group (P<0.05). Moreover the R/ TPT group treated with 2ME2 followed by IUDR had maximum DNA damage in spheroid GBM indicating an augmented genotoxicity in the cells. The DNA damage was induced after seven fractionated irradiation and two sequential treatments with 2ME2/IUDR/TPT. To ensure accuracy of the slope of dose response curve the fractionated radiation was calculated as 7.36 Gy with respect to α/β ratio based on biologically effective dose (BED) formulae.

Conclusion

Cells treated with 2ME2/IUDR showed more sensitivity to radiation and accumulative DNA damage. DNA damage was significantly increased when GBM cells treated with TPT ceased at S phase due to the inhibition of topoisomerase enzyme and phosphorylation of Chk1 enzyme. These results suggest that R/TPT- treated cells increase sensitivity to 2ME2 and IUDR especially when they are used together. Therefore, due to an increase in the level of DNA damage (SSB vs. DSB) and impairment of DNA repair machinery, more cell death will occur. This in turn may improve the treatment of GBM.

The effects of secondhand smoke exposure on infant growth: a prospective cohort study

Mother's and infant exposure to cigarette smoke is one of the most important public health problems. There is no study in Iran evaluating the impact of cigarette smoke on infant growth and development. The purpose of this study was to determine the effects of cigarette. This prospective cohort study was conducted on 51 cigarette smoke-exposed infants (exposed group) and 51 non-exposed infants (non-exposed group). They were evaluated for weight, height and head circumference three times; five to seven days, two months and four months after birth. Urine samples were also collected in each turn. Exposure to secondhand smoke was assessed through questionnaires and urinary cotinine levels. The analysis was performed using an independent t-test, Mann-Whitney U test, chi-square and Fisher's exact and Kappa tests. Mean urinary cotinine level in the exposed group was 38.57±2.85 ng/mg creatinine at baseline, 86.95±1.16 at two months and 63.32±2.08 at four months of age. These indicated a gradual reduction of exposure from two to four months. The weight and height of the exposed group were significantly lower than the non-exposed group (P< 0.001) at two and four months after birth. The results of the present study showed that the exposure to secondhand smoke during infancy may lead to weight and height growth reduction in the first four months of life.

Kinetic properties of aryldialkylphosphatase immobilised on chitosan myristic acid nanogel

Organophosphorus (OP) compounds are extensively used in agricultural practice for pest management. However, their residues have a long half-life in the ecosystem as well as in the agro-products, posing a serious threat to human and animal health. Aryldialkylphosphatase (EC 3.1.8.1) is widely used in detoxification procedures. In the present study, aryldialkylphosphatase was immobilised on synthesised cross-linked nano-sized gel particles, also known as nanogels, in order to enhance the enzyme’s physicochemical properties. Accordingly, a new nanogel consisting of chitosan and myristic acid (CMA nanogel) was synthesised and characterised by way of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The aryldialkylphosphatase-CMA nanogel conjugate was then assayed by FTIR, and its physicochemical characteristics were also investigated. The data obtained from SEM and TEM showed the nanogels to be homogenous spherical particles less than 50 nm in diameter. The proper formation of the nanogel and nanobioconjugate was also confirmed by FTIR spectra. In comparison with the free enzyme, the pH and thermal stability of the aryldialkylphosphatase were enhanced by the covalent immobilisation. Moreover, the immobilised enzyme could maintain approximately half of its activity over more than one month. The kinetic parameters of the aryldialkylphosphatase- CMA nanogel conjugate were also shown to undergo remarkable improvements, hence the synthesised CMA-nanogel could act as a promising support for aryldialkylphosphatase immobilisation. It is suggested that the aryldialkylphosphatase-CMA nanogel could be used for detoxifying paraoxon; a nerve agent. Further clinical experiments are underway.

The comparison of anticancer activity of thymoquinone and nanothymoquinone on human breast adenocarcinoma

Cancer is one of the main causes of mortality in the world which is created by the effect of enviromental physico-chemical mutagen and carcinogen agents. The identification of new cytotoxic drugs with low side effects on immune system has developed as important area in new studies of pharmacology. Thymoquinone (TQ), derived from the medicinal spice Nigella sativa (also calledt black cumin) exhibit anti-inflammatory and anti-cancer activities. In this study we employed nanogel-based nanoparticle approach to improve upon its effectiveness. Myristic acid-chitosan (MA-chitosan) nanogels were prepared by the technique of self-assembly. Thymoquinone was loaded into the nanogels. The surface morphology of the prepared nanoparticles was determined using SEM and TEM. The other objective of this study was to examine the in-vitro cytotoxic activity of cell death of Thymoquinone and nanothymoquinone on human breast adenocarcinoma cell line (MCF7). Cytotoxicity and viability of Thymoquinone and nanothymoquinone were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and dye exclusion assay. Transmission electron microscopy confirmed the particle diameter was between 150 to 200 nm. Proliferation of MCF7 cells was significantly inhibited by Thymoquinone and nanothymoquinone in a concentration-dependent manner in defined times. There were significant differences in IC50 Thymoquinone and nanothymoquinone. TQ-loaded nanoparticles proved more effective compared to TQ solution. The high drug-targeting potential and efficiency demonstrates the significant role of the anticancer properties of TQ-loaded nanoparticles.

The effect of cigarette smoke exposure on vitamin D level and biochemical parameters of mothers and neonates

BACKGROUND

Exposure to cigarette smoke during pregnancy leads to several adverse effects on mother and child. The purpose of this study was to evaluate the effect of being a passive smoker during pregnancy on vitamin D level and related biochemical indices including parathyroid hormone, calcium, phosphorus and alkaline phosphatase in mothers and newborns.

METHODS

One hundred eight pregnant women and their newborns participated in a historical cohort study in two equal groups (n = 54) with and without cigarette smoke exposure. Maternal blood and urine samples and blood samples of umbilical cord were obtained in the delivery room. Concentration of 25-hydroxy vitamin D and related biochemical indices in samples of maternal and cord blood were investigated. Exposure to cigarette smoke was evaluated through questionnaire and maternal urine and umbilical cord serum cotinine levels.

RESULTS

The mean level of 25-hydroxyvitamin D in maternal serum was 9.28 ± 5.19 ng/mlin exposed and 10.75 ± 5.26 ng/ml in non-exposed group(p > 0.05). The mean concentration of 25-hydroxy vitamin D in cord serum was 10.83 ± 6.68 ng/ml in the exposed and 11.05 ± 4.99 ng/ml in the non-exposed group(p > 0.05). The exposed mothers had significantly higher parathyroid hormone level (p = 0.013), lower serum calcium (p = 0.024) and higher serum alkaline phosphatase (p = 0.024). There was a significant correlation between maternal and umbilical cord serum 25-hydroxyvitamin D within both exposed and non-exposed groups (p < 0.001).

CONCLUSION

Maternal exposure to cigarette smoking during pregnancy negatively influences serum calcium level and increase parathyroid hormone and alkaline phosphatase in mothers.

Endothelial dysfunction in experimental atherosclerosis in the rabbit with extraction of instantaneous changes in the arterial wall

BACKGROUND

In this study, we used a new computerized analytical method for the measurement of the endothelial function in sequential ultrasound images and compared it with histological studies, using the abdominal aorta in normal and atherosclerotic rabbits.

METHODS

Six rabbits received a standard rabbit chow as the normal group and the other 6 rabbits were fed a high cholesterol diet for four weeks as the atherosclerotic group. B-mode images of the abdominal aorta with 46 frames per second were saved over three cardiac cycles at baseline and during acetylcholine or nitroglycerin drug infusion in the normal and atherosclerotic rabbits. In order to evaluate endothelial-dependent relaxation, acetylcholine-mediated dilation (AMD) was measured during the infusion of acetylcholine at a rate of 0.5 μg/kg/min and endothelial-independent relaxation was evaluated by measuring nitroglycerine-mediated dilation (NMD) during the infusion of nitroglycerin at a rate of 5 μg/kg/min. In addition, the ultrasonic evaluation was confirmed by histopathological evaluation of the abdominal aorta.

RESULTS

Significant differences in AMD were detected between the normal and the four-week cholesterol-fed rabbits (p value<0.05), whereas there were no significant differences in NMD between the two groups (p value>0.05). No microscopic intimal lesions were seen in the normal rabbits, but intimal thickening was observed in the histological studies in the four-week cholesterol-fed rabbits. Additionally, the total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels were remarkably increased in the sera of the four-week cholesterol-fed rabbits(p value<0.05).

CONCLUSION

A new automatic method can help accurately evaluate the endothelial function in normal and hypercholesterolemic rabbits.

Effect of acute ethanol treatment on biochemical and histopathological factors in rat liver in an experimental sepsis model

The aim of this study was to investigate the contribution of acute alcohol in sepsis-related liver damages using a Cecal Ligation and Puncture (CLP) model. Rats were divided into 7 groups (5 rats/group): control (saline-injected), sham-operated, CLP, ethanol (1.0 and 2.0 g/kg b.w) and CLP+ethanol. The CLP+ethanol group received a single dose of ethanol following sepsis induction. Sepsis induction caused early changes in lipid peroxidation products in liver, whereas ethanol alone (2.0 g/kg b.w) resulted in a significant increase (~21%) in lipid peroxidation, which was further increased (~57%) in CLP rats treated with alcohol. CLP operation and alcohol treatment exhibited additive effects on plasma catalase, liver glutathione and glutathione S-transferase (GST), which were primarily suppressed due to ethanol. Hepatic cytochrome P4501A1, which was elevated in CLP rats, was reversed in the CLP+ethanol group. Plasma tumor necrosis factor-α was markedly elevated (~85%) in septic rats, but was unaffected in septic rats having received ethanol. Histopathological observations revealed that inflammatory reactions in liver in response to CLP operation are not intensified by ethanol administration. On the basis of biochemical and histopathological results, it can be concluded that acute ethanol treatment is responsible for early changes in oxidative stress, which may lead to polymicrobial sepsis-related organ damage.

Development of high-throughput quantum dot biosensor against Polymyxa species

The plasmodiophoromycete Polymyxa betae and P. graminis are eukaryotic biotrophic parasites residing in the roots of chenopodiacae and gramineae plants. They are natural transmitting agents of several important plant viruses such as are beet necrotic yellow vein virus (BNYW), beet soil borne mosaic virus (BSBMV), wheat soil-borne mosaic virus (WSBMV). Developing advanced high-throughput diagnostic methods capable of accurate detection of these pathogens could assist with the screening programs and consequently with the development of disease-resistant germplasms. In the present study, a previously developed quantum dots (QDs) FRET-based nano-biosensor was upgraded to a high-throughput version. QDs were functionalized with a specific antibody against the P. betae's specific glutathione-S-transferase (GST) protein. On the other hand, GST was conjugated to Rhodamine dye. Ninety six-well polystyrene plates were used as the detection platform. The mutual affinity of the antigen and the antibody brought the CdTe QDs and rhodamine together close enough to allow the resonance dipole-dipole coupling required for fluorescence resonance energy transfer (FRET) to occur. The immunosensor constructed showed a high sensitivity and specificity of 100%, and was successfully used for high-throughput screening of 96 real samples with consistent results within the course of less than 30 minutes.

Association of self-reported passive smoking in pregnant women with cotinine level of maternal urine and umbilical cord blood at delivery

Passive smoking during pregnancy leads to adverse effects on mother and infant. The present investigation was designed to evaluate the association between maternal reported passive smoking with the cotinine concentration of maternal urine and umbilical cord blood at delivery and to determine the accuracy of maternal reporting of exposure to cigarette smoke during pregnancy. This was a cross-sectional study. From the 108 non-smoker pregnant women who were referred for delivery, 54 were passive smokers. Urine samples were collected from the mothers in the delivery room and blood samples after birth were taken from the umbilical cord. Passive smoking was evaluated through questionnaire and cotinine level of urine and umbilical cord blood. The geometric mean cotinine concentration of the maternal urine and the umbilical cord serum were, respectively, 27.4 ± 29.96 ng/mL and 3.71 ± 1.22 ng/mL in the exposed group (P < 0.001) and 0.75 ± 2.29 and 0.40 ± 0.63 in the non-exposed group (P < 0.001). There was a statistically significant correlation between maternal urinary and umbilical cord serum level of cotinine (P < 0.001, r = 0.58). Significant associations were shown between maternal reports of exposure to cigarette smoking with cotinine level of urine (kappa = 96%) and umbilical cord (kappa = 98%) (P < 0.001). This study shows that the pregnant woman's report of passive smoking during pregnancy in Iran is accurate. The questionnaire is an appropriate method to evaluate smoke exposure and could replace cotinine measurement.

DNA Damage Induced in Glioblastoma Cells by I-131: A Comparison between Experimental Data and Monte Carlo Simulation

OBJECTIVE

The passage of ionizing radiation in living cells creates clusters of damaged nucleotides in DNA. In this study, DNA strand breaks induced by the beta particle of iodine-131 (I-131), have been determined experimentally and compared to Monte Carlo simulation results as a theoretical method of determining(131)I damage.

MATERIALS AND METHODS

In this experimental study, in order to create single strand breaks (SSB) and double strand breaks (DSB) in the DNA, glioblastoma (GBM) cells were exposed to 10 mCi I-131, at a dose of 2 Gy. Damage of irradiated cells were evaluated quantitatively by the Fast Micromethod assay. The energy spectrum of electrons released in cells were obtained by the macroscopic Monte Carlo code (MCNP4c) and used as an input of the micro Monte Carlo code (MCDS). The percent of damage induced in cells was analyzed by Mann-Whitney test.

RESULTS

A significant reduction (p<0.05) in fluorescence intensity in irradiated cells compared to control cells as determined by the Fast Micromethod assay represented induced SSB and DSB damages in the DNA of irradiated cells. Comparison of experimental and theoretical results showed that the difference between the percentages of SSB per Gy was about 7.4% and DSB was about 1% per Gy.

CONCLUSION

The differences in experimental and theoretical results may be due to the algorithm of applied codes. Since the Fast Micromethod and other experimental techniques do not provide information about the amount of detailed and complex damages of DNA-like base damages, the applied Monte Carlo codes, due to their capability to predict the amount of detailed damages that occur in the DNA of irradiated cells, can be used in in vitro experiments and radiation protection areas.

Reduction of secondhand smoke exposure among healthy infants in Iran: randomized controlled trial

INTRODUCTION

The objective of this study was to assess whether counseling both mothers and fathers reduces their infants' exposure to secondhand smoke (SHS).

METHODS

Participants were 130 nonsmoking children aged less than 1 year, exposed to their fathers' or mothers' smoking, and recruited from a health center in southern Tehran. Eligible families were randomly assigned to intervention or control group. Infant urine samples were collected, and parents were interviewed at baseline and at a 3-month follow-up in each of the 2 groups. Mothers of the intervention group were provided 3 counseling sessions, one of which was face to face and 2 of which were by telephone. Fathers were provided 3 counseling sessions by telephone. Parents were also given an educational pamphlet and a sticker depicting a smoke-free home. The control group received usual care. Changes in infant urinary cotinine levels, parental cigarette consumption in the presence of the child, and home- and car-smoking bans were assessed.

RESULTS

The intervention was effective in reducing infant urinary cotinine levels (1-tailed p = .029). There was a greater decrease in the total daily cigarette consumption in the presence of the child in the intervention group compared with the control group, and the differences between the 2 groups were statistically significant (1-tailed p = .03). While the differences between home-smoking bans in the 2 groups were statistically significant (1-tailed p = .049), the differences between car-smoking bans did not reach significance.

CONCLUSION

Counseling similar to that employed in other countries can reduce infant exposure to SHS, suggesting generalizability.

Developing a rabbit model of neointimal stenosis and atherosclerotic fibrous plaque rupture

BACKGROUND

A precise understanding of the mechanism of human neointimal stenoses and atherosclerotic fibrous plaques, which give rise to thromboses in vital arteries, requires a suitable animal model that would mimic the same characteristics well. We developed a rabbit model of neointimal stenosis and fibrotic plaque rupture in the carotid artery to visualize the lesion progress and to characterize the lesion types according to the American Heart Association classification.

METHODS

Twenty-eight healthy male New Zealand white rabbits were randomly divided into two groups: The rabbits in group A (n = 14) consumed a standard chow diet, and those in group B (n = 14) were injured via perivascular cold injury using liquid nitrogen at the right common carotid artery before being fed a high cholesterol diet (1.5%) for eight weeks. Plasma lipid evaluation was performed before the sacrificing of the rabbits. At the end of every week, at least 1 rabbit from group B was sacrificed for an analysis of lesion histopathology and calculation of the area ratios of the intima to media.

RESULTS

The plasma lipid level in group B was significantly higher than that in group A (p value < 0.05). The histopathological results revealed atherosclerosis characteristics such as endothelial layer destruction, fatty streaks and lipid-containing macrophages (foam cells) formation in the intima and media layers, extracellular lipid collections, smooth muscle cells proliferation and migration, neointima formation, intima thickening and deformation, fibrotic plaque formation, and finally plaque rupture. Statistical analysis revealed a significant increase in the intima-to-media ratio at the end of the eighth week (6.41 ± 0.27, p value < 0.05).

CONCLUSION

We successfully developed a rabbit model of neointimal stenosis and atherosclerotic fibrous connective tissue plaque rupture, which is not only quickly and easily reproducible and inexpensive but also without mortality. The merits of our model render the evaluation of neointimal stenoses and fibrotic plaques and their treatment strategies more feasible in humans.

A study of the oxidation-induced conformational and functional changes in neuroserpin

BACKGROUND

Neuroserpin, a member of the Serine Proteinase Inhibitor (Serpin) superfamily, is known to be a neuroprotective factor in the focal ischemic stroke followed by reducing the microglial activation. Neuroserpin is a protein rich of methionine residues that can scavenge the free radical species which may increase its neuroprotective effect. On the other hand, the oxidative modifications of the amino acid residues in neuroserpin may lead to changes in its conformation and function. In this study, it was investigated the changes in the conformation and the function of the oxidized neuroserpin.

METHODS

Neuroserpin expressed in E. coli, BL21 or M15 harboring plasmid pQE81L containing neuroserpin cDNA. Expressed neuroserpin was purified by resin sulfopropyl A50 precharged with 0.1 M NiSO4 under denaturing condition. Neuroserpin was oxidized under oxidative stress condition in the presence of different concentration of hydrogen peroxide. The oxidation of neuroserpin was conveniently detected by a carbonyl content assay using 2, 4 dinitrophenylhydrazine. Changes in tertiary structure of neuroserpin were monitored by spectrofluorimeter to study the alteration of intrinsic fluorescence and also fluorescence of 8-anilinonaphthalin-1 sulfonic acid (ANS) in native and oxidized form of neuroserpin.

RESULTS

Total expressed neuroserpin was estimated 4-5 mg/lit in 2XYT culture media. SDS-PAGE analysis of purified neuroserpin showed a single band which reflects the efficiency of the resin SP A50 for purification of the proteins containing 6xHis tag. Carbonyl content of oxidized and native neuroserpin was estimated 12.3 +/- 0.3 and 0.45 +/- 0.05, respectively. The inhibitory activity of oxidized neuroserpin decreased up to 40-60% as compared with native form of neuroserpin. Intrinsic fluorescence and also the emission of ANS bind to the hydrophobic region of the protein altered from 380 to 85 and in the case of ANS from 105 to 150 in oxidized and native form of neuroserpin, respectively.

CONCLUSION

The decreased intrinsic fluorescence intensity, an enhancement in the fluorescence of ANS, and loss of the inhibitory activity up to 40-60% in neuroserpin, all suggested a conformational modification in the protein under the oxidative stress condition. Remaining the inhibitory activity of neuroserpin reflects that the protein tolerates the oxidative stress condition effectively.

Elevated expression of human alpha-1 antitrypsin mediated by yeast intron in Pichia pastoris

Intron-mediated enhancement has been documented in many cases to involve large positive effect on gene expression. To address this, human Alpha-1 antitrypsin (hAAT) gene was integrated into Pichia pastoris with and without a yeast intron generated from the final plasmid pBlu-exII-int-exIII and ligated into the EcoRI/BamHI multiple cloning site of the yeast shuttle vector pHIL-S1. The chimeric exon-intron complex in the middle of the naturally occurring hAAT exons II and III caused a 23-fold enhancement of hAAT expression in P. pastoris, measured through SDS-PAGE and immunoblot analyses.