Numerical modeling of drug delivery in a dynamic solid tumor microvasculature

The complicated capillary network induced by angiogenesis is one of the main reasons of unsuccessful cancer therapy. A multi-scale mathematical method which simulates drug transport to a solid tumor is used in this study to investigate how capillary network structure affects drug delivery. The mathematical method involves processes such as blood flow through vessels, solute and fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. The effect of heterogeneous dynamic network on interstitial fluid flow and drug delivery is investigated by this multi-scale method. The sprouting angiogenesis model is used for generating capillary network and then fluid flow governing equations are implemented to calculate blood flow through the tumor-induced capillary network and fluid flow in normal and tumor tissues. Finally, convection-diffusion equation is used to simulate drug delivery. Three approaches are used to simulate drug transport based on the developed mathematical method: without a vascular network, using a static vascular network, and a dynamic vascular network. The avascular approach predicts more uniform and higher drug concentration than vascular approaches since the simplified assumptions are implemented in this method. The dynamic network which uses more realistic assumptions predicts more irregular blood vessels, high interstitial pressure, and more heterogeneity in drug distribution than other two approaches.

Awareness of Religious Leaders' Fatwa and Willingness to Donate Organ

BACKGROUND

It is believed that religious leaders' positive attitude towards organ donation can be an effective factor in Muslims' inclination to donate organs.

OBJECTIVE

To assess the knowledge of freshmen students in Mashhad University of Medical Sciences about religious leaders' fatwa on organ donation and its effect on their willingness to donate organs.

METHODS

This cross-sectional study was conducted in 2013 on 400 freshmen of various medical disciplines, selected using a simple random sampling in Mashhad, Iran. Data were collected by a valid and reliable researcher-made questionnaire. Data were analyzed by multiple logistic regression analysis.

RESULTS

41.5% of the students were aware of religious authorities' views on organ donation and 55.6% were willing to donate organs. Participants' main reasons for lack of willingness to donate organs included the fear of organ donation before the brain death is confirmed (52%), unwillingness to disfigure their body (51%), and belief in the burial of organs (50%). The willingness to organ donation for students who were aware of religious leaders opinion was more than twice more than those who were not (OR: 2.56, 95% CI: 1.75-4.52). Also, female gender, the Shia religion and awareness of the correct definition of brain death were associated factors affecting the desire to donate organs, although their effects were not statistically significant on regression model.

CONCLUSION

A considerable proportion of students were not aware of the religious leaders' fatwa on organ donation. The most important factor for the desire to donate organs was the awareness of religious leaders' fatwa. Therefore, it seems necessary that religious leaders' fatwa be known to all by appropriate methods.

Investigation of the entrance surface dose and dose to different organs in lumbar spine imaging

BACKGROUND

Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology.

OBJECTIVE

The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views.

METHODS

To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging.

RESULTS

The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement.

CONCLUSION

According to the results, the GR200 has greater sensitivity than the TLD-100.

Association of pituitary specific transcription factor-1 (POU1F1) gene polymorphism with growth and biometric traits and blood metabolites in Iranian Zel and Lori-Bakhtiari sheep

The pituitary-specific positive transcription factor 1 (POU1F1) gene has been the subject of many recent studies because of its important roles in growth and development of mammals. In this study, we investigated the single nucleotide polymorphisms (SNPs) at the third exon of POU1F1 gene and its association with growth and biometric traits and blood metabolites in two Iranian sheep breeds, Zel and Lori-Bakhtiari. Blood samples from 90 Lori-Bakhtiari and 90 Zel sheep were collected to extract DNA and the 295-bp fragment of the POU1F1 gene was amplified and the restriction fragment length polymorphism (RFLP) technique was adopted for genotyping. A SNP was identified in both Lori-Bakhtiari and Zel sheep breeds, which represents a non-synonymous single base mutation at restriction site for endonuclease AciI. The results revealed differential frequencies of alleles between the two studied breeds, where A allele was more frequent in Lori-Bakhtiari breed, while G allele was more frequent in Zel breed. When POU1F1 genotypes were tested, the animals with AA genotype had a higher weaning weight than those with GG genotype (p < 0.05), however there were not significant association between genotypes and birth weight, biometric traits (body length, body height, heart girth, thigh girth and abdominal girth) and blood metabolites (triglyceride and cholesterol) of the studied breeds (p > 0.05). These findings imply that the POU1F1 polymorphism may affect weaning weight, thus can be used as a molecular marker for this production trait.

Influence of different bonding agents and composite resins on fracture resistance of reattached incisal tooth fragment

STATEMENT OF PROBLEM

Reattachment of the fractured tooth fragment should be considered as a conservative treatment and valid alternative to a composite restoration.

PURPOSE

This in vitro study was to evaluate the influence of different adhesives and composite resins on fracture resistance of dental fragment reattached to the sectioned incisal edges.

MATERIALS AND METHOD

120 sound human maxillary central incisors were selected under standard conditions and randomly divided into 3 groups, 12 sound teeth were used as a control group and the remaining teeth were assigned to 3 groups (n=36) and each group into three subgroups (n=12). The incisal third of the samples was sectioned using a diamond disk and the respective fragments were then reattached utilizing different intermediate restorative materials, namely: i) adhesive materials alone (OptiBond S or OptiBond XTR or OptiBond All-in-One; ii) Premise flowable composite and iii) Point 4 composite in the one of the mentioned adhesive interface. After storage for two weeks at 37°C and 100% humidity and then thermocycling; shear bond strength (SBS) was recorded in kilogram force (kgf) by applying a load in the middle incisal third with a Zwick Universal Testing Machine at a cross-head speed of 1 mm/min. Data was analyzed with one-way ANOVA and Tukey HSD (p< 0.05).

RESULTS

The control group had a significantly higher SBS than other groups (p= 0.001); the highest SBS values were obtained using the Premise flowable composite and OptiBond S adhesive (112.44±30.46 MPa); and the lowest with OptiBond All-in-One alone (33.97± 15.63 MPa).

CONCLUSION

Although, none of the tested materials provided fracture resistance similar to that found with the intact maxillary central incisors; utilizing the Premise flowable composite and OptiBond S adhesive improved the SBS of the reattached fragment than other materials.

Impact of endoscopic sinus surgery on the quality of life of patients with nasal polyposis

OBJECTIVES

Chronic sinusitis with polyposis (CSWP) is associated with high direct and indirect annual costs. This condition affects several aspects of daily life, and CSWP patients usually suffer from decreased quality of life (QOL). Treatment with functional endoscopic sinus surgery (FESS) is reported to improve the QOL of patients with CS. Here we evaluated the factors that affected QOL improvement in CSWP patients who were candidates for FESS.

METHODS

All patients with CSWP who were treated at the Imam Khomeini Hospital Complex in Tehan, Iran that were candidates for FESS were recruited. Patients with systemic or neurologic diseases that could affect their QOL were excluded. Clinical signs were recorded before and after FESS using the sinonasal outcome test (SNOT-22) and QOL questionnaires. The patient's history of allergic rhinitis, aspirin sensitivity, asthma and smoking was recorded. QOL and associations with clinical features were evaluated within twelve months after FESS.

RESULTS

The study included 47 patients with a mean age of 39.5 +/- 15.4 years (61.7% women). FESS resulted in significant improvements in QOL based on the SNOT-22 and QOL questionnaires (p = 0.0001 for both). Septal deviation was the only single characteristic that was significantly associated with QOL improvements.

CONCLUSION

FESS significantly improved the QOL of patients with CSWP. However, patients with septal deviation benefited the most from FESS.

A Comparison of Skin Dose Delivered with MammoSite and Multicatheter Breast Brachytherapy

BACKGROUND

Accelerated partial breast irradiation via interstitial balloon brachytherapy is a fast and effective treatment method for certain early stage breast cancers however skin, chest wall and Lung doses are correlated with toxicity in patients treated with breast brachytherapy.

OBJECTIVE

To investigate the percentage of the dose received by critical organ (skin), thermoluminescence detector was used in MammoSite brachytherpy and the ability to control skin dose between MammoSite and MultiCatheter brachytherapy was compared with each other.

METHOD

Dosimetry is carried out using a female-equivalent mathematical chest phantom and Ir-192 source for brachytherapy application.

RESULTS

Our initial results has shown good agreement with surface doses between those calculated from the treatment planning results and those measured by the thermoluminescence detector. The mean skin dose for the experimental dosimetry in MammoSite was 2.3 Gy (56.76% of prescription dose).

CONCLUSION

The results show that the MultiCatheter method is associated with significantly lower mean skin and chest wall dose than is the MammoSite. The MultiCatheter technique is quite flexible and can be applied to any size of breast or lumpectomy cavity, But in MammoSite technique, verification of balloon symmetry, balloon/cavity conformance and overlying skin thickness is essential to assure target coverage and toxicity avoidance.

Ion-imprinted polymeric nanoparticles as a novel sorbent to separate radioyttrium from Sr target

Radioyttrium (containing 86Y, 87Y and 88Y) was produced by irradiating a natSrCO3 target with 15 MeV proton beam at a current of 30 µA for 12 min. A synthesized ion imprinted (IIP) and control polymer (CP) nanoparticles as sorbents were used for the separation of radioyttrium from strontium. The sorbents were characterized by Fourier Transform Infra-red spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), Thermogravimetric analysis (TGA) and Surface area analysis. Effect of various parameters such as pH, mass sorbent, nature and volume of eluent were investigated on the percent extraction of radioyttrium ion using IIP and CP particles. Chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry, respectively. The radioyttrium recovery yield was 99.5% and the stable Sr content in the final product was estimated to be 4.5 µg mL−1. In conclusion, the suggested method in this manuscript can be used for the production of other 86/87Y radionuclides.

Dosimetric aspects of 103Pd radioactive stent source

This study aims to determine AAPM TG-60 dosimetric quantities in regions surrounding the 103Pd stent wall by MCNP5 Monte Carlo code. The Palmaz-Schatz stent was modeled by a hollow cylinder of 17.89mm length (2mm diameter) with net surface very similar to real stent. The Dose deposited per photon (Gy), relative dose, Anisotropy function, F(r,θ), and radial dose function, gL(r), were described at AAPM TG-60 protocol were generated from these values and listed in tabular format. For benchmarking, the relative dose values were verified with TG-43 and EGS4 code results at identical conditions, relative to the radial distances from surface of the stent. There were noticeable results. These physical dosimetric parameters can be used in future treatment planning systems for IVBT.