Azran Azhim

The use of sonication treatment to completely decellularize blood arteries: A pilot study

We have developed a novel sonication decellularization system to prepare completely decellularized bioscaffolds in a short treatment time. The aim of the study is to investigate the sonication decellularization efficiency and its relation with ultrasonic power output and dissolved oxygen (DO) concentration in different detergent solution. In the study, we used aorta samples to evaluate sonication decellularization efficiency, which assessed treatment duration, sonication power and SDS detergent with/without saline. The treated samples were evaluated histologically by Hematoxylin Eosin (HE) staining and scanning electron microscopic (SEM) photographs. The concentration of DO was monitored to identify the effect of sonication on cavitation-related DO concentration in the solution. From histological results, the sonication decellularization efficiency was better than the other preparation methods. Decellularization efficiency was tended to increase significantly when DO value decreasing after 6 hours of treatment. In conclusion, we conclude that sonication treatment can be used to prepare the complete decellularized scaffolds in short treatment time.

Decellularization of Meniscal Tissue Using Ultrasound Chemical Process for Tissue-Engineered Scaffold Applications

Scaffolds play a key role in the process of regeneration and morphogenesis of tissue or organ. We have studied a novel application of ultrasound irradiation to prepare decellularized tissue for tissue-engineered scaffolds. The aim of the present study is to investigate the possibility of ultrasound energy on decellularization of cartilage tissue. The samples were decellularized using 20 kHz of ultrasonic irradiation in circulated 0.3% sodium chloride (NaCl) constituent of 2% sodium dodecyl sulfate (SDS) solution. To evaluate tissue integrity and cell removal, we used hematoxylin-eosin staining. To estimate the degree of irradiated ultrasound on the sample, we used computer simulation to calculate the irradiated power distribution in solution, corresponding to the irradiation energy against to the sample. From histological results, it shows that the ultrasonic power could assist the decellularization on meniscal tissue. The decellularization efficiency was better than the other preparation methods. Because of distributions of ultrasonic irradiation to samples were non-uniform, the efficiency of cell removal could be improved by using 3 dimensional scanning system which uniformly irradiate to the sample. In conclusion, ultrasonic chemical process has a potential to improve the efficiency of decellularization for menisci.

Monitoring Carotid Blood Flow and ECG for Cardiovascular Disease in Elder Subjects

This report is to investigate the correlation between common carotid blood flow (CCBF) properties and the risk factors for cardiovascular disease. The measurement system was designed for simultaneously monitoring of CCBF and electrocardiogram (ECG) in order to get more valid information for detection and diagnosis of cardiovascular disease. In our study, blood flow velocimeter was developed to measure blood flow in carotid by using ultrasound Doppler technique. This measurement system is based on a continuous-wave (CW) Doppler ultrasound method with two semicircular piezoelectric (PZT) transducers, one continuously transmitting ultrasound, and the other continuously receiving the echoes. Eleven patients with cardiovascular disease underwent in the experiment. In the report, blood flow was compared with data from 25 healthy subjects which asymptomatic subjects putatively free of cardiovascular disease as controls. The maximum of CCBF velocity was 102.8 (SD 18.3) cm/s in the 25 healthy subjects. While, the maximum of CCBF velocities were 53.9 (SD 16.6) cm/s in the eleven cardiac patients. The data suggest that CCBF velocity decreased significantly in the cardiac patients and by simultaneously monitoring of CCBF and ECG were probably obtained more valid information to detect and diagnose cardiovascular disease at the early stage

Evaluation of blood flow velocity envelope in common carotid artery for reference data

Abstract The aim of the present study is to investigate the usefulness of envelope waveforms of blood velocity and its indices in the common carotid artery (CCA). The envelope waveforms are measured using a developed wireless measurement system. The CCA blood velocity waveforms of 202 healthy volunteers were analyzed. Multivariate analysis was used to determine the relationship between fixed factors and the selected hemodynamic data after adjusting for the fixed factors. The results revealed the effects of age, gender and exercise on the blood velocity waveforms in the CCA. The results suggest that evaluations of the envelope waveform indices are more reliable when these effects are accounted for. The normal blood velocity parameters in CCA are determined from 202 healthy subjects in the age range 20–69 years after adjusting for the effects of gender and exercise. The findings are expected to be a reference data for healthcare and clinical evaluations.

Blood Flow Velocities in Common Carotid Artery Changes with Age and Exercise Study by using of telemetry method

Measurement of blood flow velocity using Doppler ultrasound has become an important noninvasive tool not only in the diagnosis of cardiovascular disease but also in physiological measurement. Physiological blood flow velocities in common carotid artery (CCA) is altered markedly with advancing age. It is unknown that regular aerobic exercise training can alter and improve blood flow velocity waveforms in either healthy young or healthy older individuals. Blood flow velocities were measured in 89 putatively healthy volunteers with age range of 20-76 years: 65 subjects were sedentary and 24 subjects were regular exercise-trained. Blood flow velocity spectra were measured at resting using our newly developed portable telemetry Doppler ultrasound velocimeter (TDUV) with real-time monitoring. Blood flow velocity waveforms were obtained from the spectral blood flow velocities of instantaneous peak-velocities. As a result, blood flow in peak systolic SI, end-diastolic d, and peak diastolic velocities D decreased with aging by the following yearly rate: 7.18 mm/s/year, 2.64 mm/s/year, and 1.24 mm/s/year, respectively. Thus the indices of d/S1, S1/S2, and D/I had a significant change with age. However, resting heart rate (HR) and second systolic velocities S2 were not significantly changed with aging. Blood flow velocities in SI were higher in the exercise-trained, whereas S2, D, and d velocities had no difference between trained and sedentary adults. However, the index of D/I had a marked higher in exercise-trained adults. As anticipated to exercise effect, the resting heart rate (HR) were significantly lower in exercise-trained. There were no differential effects in three age-groups (P= NS, by multivariate analysis). In conclusion, an age-associated decrease blood flow velocities in CCA was altered and improved in the healthy middle-aged and older individuals who regularly performed aerobic exercise. The blood flow patterns in three age-groups design had no markedly change with age in regular aerobic exercise-trained adults. The adaptations of blood flow velocities to regular exercise were not different with aging.

Effects of Aging and Exercise Training on the Common Carotid Blood Velocities in Healthy Men

An age-related alteration in the cardiovascular response to exercise training are evident. The purpose of the study was to investigate the effects of exercise and age on blood velocities in common carotid artery in 82 healthy men between the age ranges of 21 to 67 years old. Blood velocities are characterized to five components of velocity waveforms as peak systolic (SI), second systolic (S2), incisure between systole and diastole (I), peak diastolic (D) and end-diastolic velocity wave (d). Decrease of blood velocities in peak systolic (r=-0.711, P< 0.0001) and in peak diastolic velocities (r=-0.521, P< 0.0001) with aging are improved and partially restore in particularly older men. The velocity ratio of S2/S2-1 as a reflection index increase with age (r= 0.797, P< 0.0001), however is smaller in exercise-trained older compared with sedentary peers. The ratio of 1-I/D as a vascular elastic recoil index decrease with aging (r=-0.640, P<0.0001), but is relatively higher in exercise-trained men. Exercise training improves the age-related deterioration in blood velocities and its indices in healthy men. In the further investigations, the assessment of aerobic fitness and vascular aging has potential by using the criteria of peak systolic and peak diastolic, and its indices.

Exercise Training Improved Blood Flow Velocity and Autonomic Nervous Activity

The present study aimed to investigate non-invasively the effects of a short-term 4 week aerobic training program on the resting common carotid artery (CCA) blood flow velocity waveforms and autonomic nervous activity in young sedentary healthy subjects. It was hypothesis that training-induced the enhancement of blood flow is associated with the improvement of autonomic nervous function. The CCA blood velocities were measured for 3 minutes at resting sitting posture with synchronized measurement of electrocardiogram (ECG) and brachial blood pressure (BP). Autonomic activity was assessed by low frequency (LF) power, as an index of sympathetic activity and high frequency (HF) power, as an index of parasympathetic activity obtained from power spectral of RR intervals. Training exercise-induced the significant enhancement of all blood velocity waveforms is associated with decreasing of heart rate at rest. The evidence of improvement in training was reinforced by a significant reduction in peripheral vascular resistance and increase in heart rate variability (HRV) and HF power of HRV analysis, an index of vagal tone or parasympathetic activity. However, systolic (SBP), diastolic (DBP) and its mean blood pressure (MBP) are not significantly changed with the training. We conclude that short-term aerobic exercise training could improve cardiovascular and autonomic nervous system functions in the sedentary young men. With the further study, training effect may be simply evaluated using the non-invasive measurement system of blood velocities in CCA.

Decellularization of Living Tissue Using Microwave Chemical Process for Tissue-Engineered Scaffold Applications

Scaffolds play a key role in the process of regeneration and morphogenesis of tissue or organ. We have studied a novel application of microwave radiation to prepare decellularized tissue for tissue-engineered scaffolds. The aim of the present study is to investigate the possibility of microwave effects on decellularization of soft and cartilage tissues. The targeted tissues were decellularized using 2450 MHz of microwave radiation in pulse-circulated 0.9% sodium chloride constituent of 1% sodium deoxycholate solution. To evaluate tissue integrity and cell removal, we used hematoxylin-eosin staining and scanning electron microscope. To investigate the effect of microwave power on targeted sample, we evaluate the radiated microwave distribution in microwave oven using thermograpic camera. Histological results suggest that microwave power influenced the decellularization of samples. It is significantly decellularized, when compared with the other preparation methods. Due to distributions of microwave radiation in the oven are non-uniform, the efficiency of cell removal can be improved by fitting the sample at uniform distribution and higher radiation spot of microwave. In conclusion, combination of microwave radiation and chemically detergent process has potential to decellularize various tissues, even tendon tissue. However, optimization of electromagnetic field in the oven is needed to perform in the further study to improve the decellularization efficiency.

Wireless blood velocity spectra measurement system for healthcare evaluation: Reference data

The aim of the present study was to determine the blood velocity and its indices in common carotid artery (CCA) as reference value for clinical and healthcare application using the constructed portable wireless Doppler blood flow velocimeter system. Evaluation of CCA blood velocity waveforms was performed in 202 healthy volunteers in the age range of 20 to 69 years. Multivariate analysis was used to determine the relationship between the fixed factor and the outcome hemodynamic variables after adjustment for the related covariates. Results show a general age-related decrease in flow velocities and change in the velocity waveform. There is also a gender difference in velocity indices, except for peak systolic blood velocity. Gender difference is also found in systolic and pulse blood pressures. The findings suggest that waveform indices provide a more reliable evaluation of effects of aging and gender on CCA flow. In conclusion, normal CCA blood velocity parameters are determined in a total of 202 healthy volunteers between the third and seventh age decade after adjustment for gender and exercise effects. Findings may contribute to improved means of healthcare monitoring and clinical evaluation.

Role of exosomes as a proinflammatory mediator in the development of EBV-associated lymphoma

Epstein-Barr virus (EBV) causes various diseases in the elderly, including B-cell lymphoma such as Hodgkins lymphoma and diffuse large B-cell lymphoma. Here, we show that EBV acts in trans on noninfected macrophages in the tumor through exosome secretion and augments the development of lymphomas. In a humanized mouse model, the different formation of lymphoproliferative disease (LPD) between 2 EBV strains (Akata and B95-8) was evident. Furthermore, injection of Akata-derived exosomes affected LPD severity, possibly through the regulation of macrophage phenotype in vivo. Exosomes collected from Akata-lymphoblastoid cell lines reportedly contain EBV-derived noncoding RNAs such as BamHI fragment A rightward transcript (BART) micro-RNAs (miRNAs) and EBV-encoded RNA. We focused on the exosome-mediated delivery of BART miRNAs. In vitro, BART miRNAs could induce the immune regulatory phenotype in macrophages characterized by the gene expressions of interleukin 10, tumor necrosis factor-α, and arginase 1, suggesting the immune regulatory role of BART miRNAs. The expression level of an EBV-encoded miRNA was strongly linked to the clinical outcomes in elderly patients with diffuse large B-cell lymphoma. These results implicate BART miRNAs as 1 of the factors regulating the severity of lymphoproliferative disease and as a diagnostic marker for EBV+ B-cell lymphoma.