Characterization of folate-chitosan-DNA nanoparticles for gene therapy

Gene therapy using polymers such as chitosan shows good biocompatibility, but low transfection efficiency. The mechanism of folic acid (FA) uptake by cells to promote targeting and internalization could improve transfection rates. The objective of this study was to synthesize and characterize FA-chitosan-DNA nanoparticles and evaluate their cytotoxicity in vitro. Chitosan-DNA and FA-Chitosan-DNA nanoparticles were prepared using reductive amidation and a complex coacervation process. The effect of charge ratio on the properties of these nanoparticles was monitored by laser scattering. DNA inclusion and integrity was evaluated by gel electrophoresis. Cell viability was illustrated with the MTT assay. Charge ratio (N/P) controlled the nanoparticles size and their zeta potential. Nanoparticles presented a mean size of 118 nm and 80% cellular viability compared to 30% cell viability using LipofectAMINE2000 controls. Gel electrophoresis showed intact DNA within the carriers. FA-nanoparticles have lower cytoxicity, good DNA condensation, positive zeta potential and particle size around 118 nm, which makes them a promising candidate as a non-viral gene vector.     

Variable histological and ultrasonic characteristics of restenosis after drug-eluting stents

Bare-metal stents have undergone intense pathological and clinical examination, but histological characterization of drug-eluting stent (DES) restenosis (ISR) remains unknown. We report a series of cases (n = 6) with intravascular ultrasound (IVUS) and pathological examinations over 8 months after DES deployment. Tissue samples were obtained using atherectomy devices in 5 cases and a thrombectomy catheter in 1 case. Histology revealed not only smooth muscle cell proliferation, which correlated with homogeneous hypoechoic tissue by IVUS in one case, but also demonstrated delayed healing features such as organized fibrin deposition in 3 cases (one with homogeneous echolucent tissue by IVUS), macrophage and T-lymphocyte infiltration in others. IVUS appearance of ISR components varied from echolucent to echodense images. This report suggests a variable histological and IVUS pattern of ISR after DES implantation. Further investigations are necessary to define the potentially pro-thrombotic histological features of ISR after DES implantation, and the relationship between the molecular mechanisms of thrombosis and DES restenosis.     

Oxygenator exhaust capnography for prediction of arterial carbon dioxide tension during hypothermic cardiopulmonary bypass

Continuous monitoring and control of arterial carbon dioxide tension (P(a)CO2) during cardiopulmonary bypass (CPB) is essential. A reliable, accurate, and inexpensive system is not currently available. This study was undertaken to assess whether the continuous monitoring of oxygenator exhaust carbon dioxide tension (PexCO2) can be used to reflect P(a)CO2 during CPB. A total of 33 patients undergoing CPB for cardiac surgery were included in the study. During normothermia (37 degrees C) and stable hypothermia (31 degrees C), the values of PexCO2 from the oxygenator exhaust outlet were monitored and compared simultaneously with the P(a)CO2 values. Regression and agreement analysis were performed between PexCO2 and temperature corrected-P(a)CO2 and temperature uncorrected-P(a)CO2. At normothermia, a significant correlation was obtained between PexCO2 and P(a)CO2 (r = 0.79; p < 0.05); there was also a strong agreement between PexCO2 and P(a)CO2 with a gradient of 3.4 +/- 1.9 mmHg. During stable hypothermia, a significant correlation was obtained between PexCO2 and the temperature corrected-P(a)CO2 (r = 0.78; p < 0.05); also, there was a strong agreement between PexCO2 and temperature corrected-P(a)CO2 with a gradient of 2.8 +/- 2.0 mmHg. During stable hypothermia, a significant correlation was obtained between PexCO2 and the temperature uncorrected-P(a)CO2 (r = 0.61; p < 0.05); however, there was a poor agreement between PexCO2 and the temperature uncorrected-P(a)CO2 with a gradient of 13.2 +/- 3.8 mmHg. Oxygenator exhaust capnography could be used as a mean for continuously monitoring P(a)CO2 during normothermic phase of cardiopulmonary bypass as well as the temperature-corrected P(a)CO2 during the stable hypothermic phase of CPB.     

Non-travel-associated hepatitis E in England and Wales: demographic, clinical, and molecular epidemiological characteristics

Between 1996 and 2003, 186 cases of hepatitis E were serologically diagnosed. Of these, 17 (9%) were not associated with recent travel abroad. Patients were >55 years old (range, 56-82 years old) and tended to be male (76%). Two patients presented with fulminant hepatitis. A total of 129 (69%) cases were associated with recent travel to countries where hepatitis E virus (HEV) is hyperendemic. Compared with patients with travel-associated disease, patients with non-travel-associated disease were more likely to be older, living in coastal or estuarine areas, not of South Asian ethnicity, and infected by genotype 3 strains of HEV. The genotype 3 subgenomic nucleotide sequences were unique and closely related to those from British pigs. Patients infected by HEV indigenous to England and Wales tended to belong to a distinct demographic group, there were multiple sources of infection, and pigs might have been a viral reservoir.     

Histone deacetylase inhibitors prevent apoptosis following lethal hemorrhagic shock in rodent kidney cells

Background

We have previously demonstrated that treatment with histone deacetylase inhibitors (HDACI), such as valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA), can improve survival after hemorrhagic shock in animal models. Hemorrhage results in hypoacetylation of proteins which is reversed by HDACI. These agents are known to acetylate insulin receptor substrate-I (IRS-I), which in turn activates the Akt survival pathway. This study investigated whether HDACI exert their beneficial effects through the Akt survival pathway.

Methods

Wistar-Kyoto rats (N = 21) underwent hemorrhage (60% blood loss) and were randomized into 3 groups; no resuscitation (NR), and treatment with VPA or SAHA. Kidneys were harvested at 1, 6, and 24 h after HDACI treatment and analyzed for acetylated histone 3 at lysine 9 residue (Ac-H3K9), phosphorylated Akt (phospho-Akt), BAD and Bcl-2 proteins.

Results

Hemorrhaged animals were in severe shock, with mean arterial pressures of 25-30 mm Hg and lactic acid 7-9 mg/ml. Only animals treated with VPA and SAHA survived to the 6- and 24-h timepoints. Treatment with HDACI produced a biologic effect on rat kidney cells inducing acetylation of histone H3K9, which peaked after 1 h of treatment, and was statistically significant in the VPA group (p = 0.01) compared to NR. Phospho-Akt protein increased in the VPA group with a reciprocal decrease in the pro-apoptotic BAD protein in both groups which was statistically significant in the VPA group after 1 h (p = 0.007) and 24 h (p = 0.006) of treatment and in the SAHA group after 24 h of treatment (p = 0.028). Anti-apoptotic Bcl-2 protein markedly increased after 6 (p = 0.04) and 24 h (p = 0.014) of VPA treatment. Bcl-2 also increased in the SAHA group, but failed to reach statistical significance.

Conclusion

Treatment with HDACI increases phosphorylation of Akt with a subsequent decrease in the pro-apoptotic BAD protein. The above mechanism facilitates the action of anti-apoptotic protein Bcl-2. HDACI protect kidney cells subjected to hemorrhagic shock in rodents through the Akt survival pathway.     

A novel haplotype in ABCA1 gene effects plasma HDL-C concentration

On the basis of pathological, angiographical, intravascular ultrasound and computed tomography data coronary atherosclerosis appears to be more prevalent in the left coronary arterial system compared to the right. However, the pathophysiological mechanisms implicated in this discrepancy largely remain uncertain. The hemodynamic or anatomical differences between the right and left coronary artery might play a key role. Physiologically, the right coronary flow is more uniform during the cardiac cycle compared to the left, which experiences a remarkable systolic decline accompanied by a significant diastolic increment. Thus, the oscillatory shear stress, that constitutes a proved atherogenic factor, is more intense in regions with disturbed flow in the left coronary system. Likewise, the wall stress is more oscillatory during the cardiac cycle in the left coronary artery. On top of that, several differences regarding the anatomical configuration (3D geometry, branching) and the phasic motion between the right and the left arterial system appear to play a critical role in the modulation of the local atherogenic environment. Therefore, it could be assumed that the flow characteristics along with the geometrical and phasic motion patterns generate an intense oscillation of the imposed to the arterial wall stresses, especially in the left coronary artery. Over the long-term, these augmented oscillatory stresses, in combination with the effect of systemic risk factors, might modulate a more atherogenic environment in the atherosclerosis-prone regions of the left coronary system.