Controlled drug delivery from chitosan-coated heparin-loaded nanopores anodically grown on nitinol shape-memory alloy

Nitinol (NiTi shape-memory alloy) is an interesting candidate in various medical applications like dental, orthopedic, and cardiovascular devices, owing to its unique mechanical behaviors and proper biocompatibility. The aim of this work is the local controlled delivery of a cardiovascular drug, heparin, loaded onto nitinol treated by electrochemical anodizing and chitosan coating. In this regard, the structure, wettability, drug release kinetics, and cell cytocompatibility of the specimens were analyzed in vitro. The two-stage anodizing process successfully developed a regular nanoporous layer of Ni-Ti-O on nitinol, which considerably decreased the sessile water contact angle and induced hydrophilicity. The application of the chitosan coatings controlled the release of heparin mainly by a diffusional mechanism, where the drug release mechanisms were evaluated by the Higuchi, first-order, zero-order, and Korsmeyer-Pepass models. Human umbilical cord endothelial cells (HUVECs) viability assay also showed the non-cytotoxicity of the samples, so that the best performance was found for the chitosan-coated samples. It is concluded that the designed drug delivery systems are promising for cardiovascular, particularly stent applications.

Amine functionalized benzene based hypercrosslinked polymer as an adsorbent for CO2/N2 adsorption

In this work, benzene based hypercrosslinked polymer (HCP) as an adsorbent was modified using amine group to enhance CO₂ uptake capability and selectivity. Based on BET analysis result, the HCP and the modified HCP provide surface area of 806 (m² g^-1) and micropore volume of 453 (m² g^-1) and 0.19 (cm³ g^-1) and 0.14 (cm³ g^-1), respectively. The CO₂ and N₂ gases adsorption were performed in a laboratory scale reactor at a temperature between 298 and 328 K and pressure up to 9 bar. The experimental data were evaluated using isotherm, kinetic and thermodynamic models to identify the absorbent behavior. The maximum CO₂ adsorption capacity at 298 K and 9 bar was obtained 301.67 (mg g^-1) for HCP and 414.41 (mg g^-1) for amine modified HCP. The CO₂ adsorption thermodynamic parameters assessment including enthalpy changes, entropy changes, and Gibbs free energy changes at 298 K were resulted - 14.852 (kJ mol^-1), - 0.024 (kJ mol^-1 K^-1), - 7.597 (kJ mol^-1) for HCP and - 17.498 (kJ mol^-1), - 0.029(kJ mol^-1 K^-1), - 8.9 (kJ mol^-1) for amine functionalized HCP, respectively. Finally, the selectivity of the samples were calculated at a CO₂/N₂ composition of 15:85 (v/v) and 43% enhancement in adsorption selectivity at 298 K was obtained for amine modified HCP.

Thermodynamic modeling of binary mixtures of ethylenediamine with water, methanol, ethanol, and 2-propanol by association theory

In this work, CPA EoS was applied to study the VLE of EDA–water, EDA–methanol, EDA–ethanol, and EDA–2-propanol. CPA EoS with the aid of presented information in this study is capable of describing thermodynamic behaviour of studied systems.

TMEM263: a novel candidate gene implicated in human autosomal recessive severe lethal skeletal dysplasia

INTRODUCTION

Skeletal dysplasia is a common, clinically and genetically heterogeneous disorder in the human population. An increasing number of different genes are being identified causing this disorder. We used whole exome sequencing (WES) for detection of skeletal dysplasia causing mutation in a fetus affected to severe lethal skeletal dysplasia.

PATIENT

Fetus was assessed by ultrasonography in second trimester of pregnancy. He suffers from severe rhizomelic dysplasia and also pathologic shortening of ribs. WES was applied to finding of causal mutation. Furthermore, bioinformatics analysis was performed to predict mutation impact.

RESULTS

Whole exome sequencing (WES) identified a homozygous frameshift mutation in the TMEM263 gene in a fetus with severe lethal skeletal dysplasia. Mutations of this gene have been previously identified in dwarf chickens, but this is the first report of involvement of this gene in human skeletal dysplasia. This gene plays a key role in the growth hormone signaling pathway.

CONCLUSION

TMEM263 can be considered as a new gene responsible for skeletal dysplasia. Given the complications observed in the affected fetus, the mutation of this gene appears to produce much more intense complications than that found in chickens and is likely to play a more important role in bone development in human.

The risk factors and laboratory diagnostics for post renal transplant tuberculosis: a case-control, country-wide study on definitive cases

BACKGROUND

Tuberculosis (TB) is an important cause of morbidity and mortality in renal transplant recipients and, because of its infrequency and the lack of medical awareness, it is usually misdiagnosed. This study was carried out to determine frequency and weight of multiple risk factors for post kidney transplantation TB.

METHODS

A total of 44 cases (0.3%), out of 12,820 patients from 12 major kidney transplantation centers in Iran from 1984 to 2003, were compared with 184 healthy transplant subjects who were transplanted by the same surgical team.

RESULTS

The mean age of cases and controls was 37.7 (13-63) and 35.6 (8-67) years (P=0.3), respectively. The mean duration of pre-transplantation hemodialysis was 30.3 (3-168) months in cases and 18.2 (1-180) months in controls (P=0.03). A positive past history of TB was detected in 2 cases and 1 control (P=0.3). The mean doses of initial and maintenance immunosuppressive drugs in cases and controls were not significantly different. A total of 25 cases (56.8%) and 60 controls (32.6%) had rejection before diagnosis of TB (P=0.004; OR=2.7, CI(95%): 1.3-5.6).

CONCLUSIONS

To our knowledge, this is the first study that demonstrated an increase in the risk of post-transplant TB by increasing the duration of pre-transplant hemodialysis and the number of post-transplant rejection episodes as 2 immunocompromised states. Further study is needed to clarify our new findings, specifically in relation to different immunosuppressive regimens.

Preliminary Report of a Nationwide Case-Control Study for Identifying Risk Factors of Tuberculosis Following Renal Transplantation

BACKGROUND

Tuberculosis (TB) is an important infection encountered posttransplantation, especially among patients in developing countries, where there are high incidences of morbidity and mortality.

MATERIALS AND METHODS

One hundred and twenty subjects (1%) from 15 major kidney transplantation centers in Iran from 1984 to 2003 were compared with 440 controls who were matched for operative time, treatment center, and surgical team.

RESULTS

Mean ages of research subjects and controls were 38.6 and 36.6 years (P = .04), respectively. The mean duration of pretransplantation hemodialysis was 29 months (range, 2 to 192 months) in research subjects and 20 months (range, 1 to 180 months) in controls (P = .003). Positive past history of tuberculosis was detected in 4 (3.3%) research subjects and in 7 (1.5%) controls (P = .2). Fifty-two research subjects (43.3%) and 241 controls (54.8%) had pretransplantation purified protein derivative of tuberculin less than 5 mm (P = .02). Mean dosages of initial and maintenance immunosuppressive drugs in research subjects and in controls were not significantly different. Sixty research subjects (50%) and 152 controls (34.5%) had rejection prior to diagnosis of TB (P = .03).

CONCLUSION

To our knowledge, this is the first study that demonstrates an increased risk of posttransplant TB by prolonged duration of pretransplant hemodialysis and number of posttransplant rejection episodes. Further study is needed to clarify these findings specifically with respect to various immunosuppressive regimens.