Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound.

BACKGROUND: Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic substances. Fouling of pores in dialysis membrane caused by adhesion of plasma protein and other toxins will reduce the efficacy of the filtre. OBJECTIVE: In This study, the influence of pulsed ultrasound waves on diffusion and the prevention of fouling in the filter membrane were investigated. MATERIAL AND METHODS: Pulsed ultrasound waves with frequency of 1 MHz at an intensity of 1 W/cm2 was applied to the high flux (PES 130) filter. Blood and blood equivalent solutions were passed through the filter in separate experimental setups. The amount of Creatinine, Urea and Inulin cleared from both blood equvalent solution and human whole blood passed through High Flux (PES 130) filter were measured in the presence and absence of ultrasound irradiation. Samples were taken from the outlet of the dialyzer every five minutes and the clearance of each constituent was calculated. RESULTS: Statistical analysis of the blood equvalent solution and whole blood indicated the clearance of Urea and Inulin in the presence of ultrasound increased (p<0.05), while no significant effects were observed for Creatinine. CONCLUSION: It may be concluded that ultrasound, as a mechanical force, can increase the rate of clearance of some toxins (such as middle and large molecules) in the hemodialysis process.

Effects of Ultrasound Irradiation on the Release Profile of 5-fluorouracil from Magnetic Polylactic co-glycolic Acid Nanocapsules.

BACKGROUND: Drug nano-carriers are one of the most important tools for targeted cancer therapy so that undesired side effects of chemotherapy drugs are minimized. In this area, the use of ultrasound can be helpful in controlling drug release from nanoparticles to achieve higher treatment efficiency. OBJECTIVE: Here, we studies the effects of ultrasound irradiation on the release profile of 5-fluorouracil (5-Fu) loaded magnetic poly lactic co-glycolic acid (PLGA) nanocapsules. METHODS: 5-Fu loaded magnetic PLGA nanocapsules were synthesized by multiple emulsification method. Particle size was measured by dynamic light scattering (DLS) and transmission electron microscope (TEM). The pattern of drug release was assessed with and without 3 MHz ultrasound waves at intensities of 0.3, 0.5 and 1 w/cm2 for exposure time of 5 and 10 min in phosphate-buffered saline (PBS). RESULTS: The size of nanoparticles was about 70 nm. Electron microscope images revealed the spherical shape of nanoparticles. The results demonstrated that the intensity and exposure time of ultrasound irradiation have significant effects on the profile of drug release from nanoparticles. CONCLUSION: It may be concluded that the application of ultrasound to control the release profile of drug loaded nanocapsules would be a promising method to develop a controlled drug delivery strategy in cancer therapy.

Effects of Low-Intensity Continuous Ultrasound on Hematological Parameters of Rats.

BACKGROUND: Low intensity ultrasound (US) has some well-known bio-effects which are of great importance to be considered. Objective: We conducted the present study to investigate the effects of low intensity continuous ultrasound on blood cells count in rat. METHODS: Rats were anesthetized and blood samples were collected before US exposure. Then, they were exposed to US with nominal intensity of 0.2 W/cm2 at frequency of 3 MHz for a period of 10 minutes and this protocol was repeated for 7 days. Twenty four hours after the last US exposure, secondary blood samples were collected and the changes in blood parameters were evaluated. RESULTS: Analysis revealed that platelets, hematocrit (HCT) and hemoglobin (HGB) were significantly different between experimental and sham groups but no difference between sham and control groups was observed. The results show that HCT and HGB of exposed rats were significantly reduced. Conclusion: This study shows that low intensity US may lead to side effects for hematological parameters such as reduction in the levels of HGB and HCT.

K-edge ratio method for identification of multiple nanoparticulate contrast agents by spectral CT imaging.

OBJECTIVE: Recently introduced energy-sensitive X-ray CT makes it feasible to discriminate different nanoparticulate contrast materials. The purpose of this work is to present a K-edge ratio method for differentiating multiple simultaneous contrast agents using spectral CT. METHODS: The ratio of two images relevant to energy bins straddling the K-edge of the materials is calculated using an analytic CT simulator. In the resulting parametric map, the selected contrast agent regions can be identified using a thresholding algorithm. The K-edge ratio algorithm is applied to spectral images of simulated phantoms to identify and differentiate up to four simultaneous and targeted CT contrast agents. RESULTS: We show that different combinations of simultaneous CT contrast agents can be identified by the proposed K-edge ratio method when energy-sensitive CT is used. In the K-edge parametric maps, the pixel values for biological tissues and contrast agents reach a maximum of 0.95, whereas for the selected contrast agents, the pixel values are larger than 1.10. The number of contrast agents that can be discriminated is limited owing to photon starvation. For reliable material discrimination, minimum photon counts corresponding to 140 kVp, 100 mAs and 5-mm slice thickness must be used. CONCLUSION: The proposed K-edge ratio method is a straightforward and fast method for identification and discrimination of multiple simultaneous CT contrast agents. ADVANCES IN KNOWLEDGE: A new spectral CT-based algorithm is proposed which provides a new concept of molecular CT imaging by non-iteratively identifying multiple contrast agents when they are simultaneously targeting different organs.

Effects of human placental serum on proliferation and morphology of human adipose tissue-derived stem cells.

Media used for tissue culture may have significant effects on the growth and morphology of the adipose tissue-derived stem cells (ADSCs). As fetal bovine serum (FBS) may induce an immunological reaction and health risks, this study was designed to evaluate and compare the effects of human placental serum (HPS) on the proliferation and morphology of hADSCs. We cultured hADSCs for at least three passages in four different culture media containing either FBS, HPS, autologous serum (AS) or human allogeneic serum (HAS). Morphological and immunophenotypic characteristics, as well as proliferation rates of the hADSCs were determined. The rates of proliferation of hADSCs seemed as follows: AS≥HPS>HAS>>FBS. Morphologically, hADSCs isolated and expanded in medium containing HPS were similar to those grown in medium containing AS, whereas the morphology of cells cultured in human sera was different in comparison with FBS-ADSCs cultures. The immunophenotypic markers of hADSCs grown up in medium containing placental serum such as CD44+, CD90+ and CD105+, were similar to hADSCs grown up in media containing other sera. These results indicate that medium enriched with HPS provided a better microenvironment for hADSCs in comparison with medium enriched with commercially available FBS, and other human sera.

Some of the factors involved in the Sarvazyan method for recording ultrasound field distributions with special reference to the application of ultrasound in physiotherapy.

The mapping of ultrasound fields using the dye paper method is described. The mode of action by which the dye concentration is increased has been investigated. Microbubbles on the paper surface and microstreaming of dye solution seem to be essential features of the mapping method. The streaming is thought to inhibit the formation of a dye depletion layer near the paper to an extent dependent on local sound intensity A linear relation between streaming velocity and intensity is derived.

Possible explanation for the unexpected absence of gross biological damage to membranes of cells insonated in suspension and in surface culture in chambers exposed to standing and progressive wave fields.

Quoted values of cavitation thresholds reported in the literature vary over several orders of magnitude. This paper describes an investigation of the threshold in a chamber with acoustically transparent windows, situated around the last axial maximum of a 0.75 MHz standing wave field. The chamber, the transducer and the reflector are submerged in a tank containing distilled water which also fills the chamber. The formation of bubbles outside the chamber, both above and below it, occurred at lower intensities than those needed to generate bubbles in the chamber. This unexpected finding led to a theoretical study of streaming patterns in progressive and standing wave fields. These showed that there is a region around the last axial maximum in which there is no gradient of energy density. Therefore if this region is enclosed by an acoustically transparent chamber, no significant bulk streaming occurs within it. We speculate on how this lack of streaming raises the cavitation threshold. The cavitation phenomenon is also examined by Doppler ultrasound of frequency 8 MHz. This confirms the occurrence of increased intensity thresholds within the chamber. It also shows that the time between filling the chamber and the start of sonication strongly influences the magnitude of the cavitation threshold. We expect that the effects described here may have consequences for sonication of cells in suspension culture when the samples are held in chambers situated around the last axial maximum of an ultrasound beam from a plane transducer.