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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 209-212, 2017 Jul.
Article in English | MEDLINE | ID: mdl-29059847

ABSTRACT

Low-intensity ultrasound can be used for noninvasive neuromuscular stimulation to enhance the recovery of injured peripheral nerves and muscles. In order to improve the stimulation efficiency, focused ultrasound (FUS) with a high energy density should be used. Because the FUS is concentrated at a miniaturized focal area, deliberate targeting with focal depth control is required to achieve the accurate stimulation. In this study, a low-intensity focused ultrasound (LIFU) stimulator with a focal depth controller is presented as an effective ultrasound stimulation system for the neuromuscular rehabilitation. In the developed stimulator, the target depth is adjusted by the focal depth controller with the brief structure. The experimental results show that the developed stimulator can generate the high quality LIFU stimulation with the spatial average-pulse average intensity (ISAPA) of 496 mW/cm2, which is sufficient to improve the rehabilitation of injured peripheral nerves and muscles. In the in vivo experiment, a rat's sciatic nerve was successfully targeted by the developed stimulator. These results indicate that the developed stimulator can be used to improve the quality of the ultrasound stimulation for neuromuscular rehabilitation by targeting a specific area.


Subject(s)
Neuromuscular Diseases/rehabilitation , Animals , Medicine , Peripheral Nerves , Rats , Ultrasonography
2.
Article in English | MEDLINE | ID: mdl-25570305

ABSTRACT

For a retinal prosthesis, retinal nerve cells are electrically stimulated by current pulses. Typically, the amplitude of the current pulses is modulated to control the amount of injected charges. However, a high spatial resolution can be difficult to achieve with this amplitude modulation method, because the neural response spreads more widely as the amplitude of the current pulses is increased. In this paper, a biphasic current stimulator integrated circuit (IC) using a new modulation method called, the pulse count modulation, is proposed. In the pulse count modulation method, the amplitude and the width of the current pulses are fixed, and the amount of injected charges is controlled by the number of applied current pulses in a base period. The proposed stimulator IC is fabricated by a 0.35 µm bipolar-CMOS-DMOS (BCDMOS) technology. The operation and performance of the stimulator IC are evaluated in an in vitro experiment environment with rd 1 mice. It is shown that a higher spatial resolution can be achieved compared with the amplitude modulation method.


Subject(s)
Electric Stimulation/methods , Visual Prosthesis , Animals , Computer Simulation , Computer Systems , Disease Models, Animal , Electronics , Electrophysiological Phenomena , Heart Rate , Macular Degeneration/therapy , Mice , Microelectrodes , Neurons/pathology , Prosthesis Design , Retina/physiopathology , Retinal Neurons/pathology
3.
Korean Circulation Journal ; : 424-430, 2006.
Article in Korean | WPRIM (Western Pacific) | ID: wpr-32329

ABSTRACT

BACKGROUND AND OBJECTIVES: Sirolimus-eluting stents (SES), as opposed to bare metal stents (BMS), have been shown to markedly reduce restenosis. However, many clinical trials have excluded the subset of patients (pts) with end-stage renal disease (ESRD). The aim of this study was to evaluate the clinical outcomes following SES implantation in ESRD pts. SUBJECTS AND METHODS: We analyzed the clinical outcomes in 50 pts from our registry following SES implantation, and compared the outcomes between those with ESRD receiving SES (SES-ESRD) and BMS (BMS-ESRD), and with non-ESRD pts following SES implantation (SES-non ESRD). RESULTS: A comparison of the SES-ESRD (50 pts, 72 lesions) with BMS-ESRD groups (42 pts, 45 lesions); those in the SES-ESRD group included; diabetes 78%, hypertension 94% and age 62+/-10 years. Those in the SES-ESRD group were more likely to have diabetes (diabetes of BMS-ESRD, 57%; p=0.04). The reference vessel diameters (RVD) of the SES-ESRD group were smaller (2.76+/-0.50 mm vs. 3.05+/-0.46 mm, p<0.001), but the lesion length was longer (25.6+/-7.0 mm vs. 19.1+/-8.8 mm, p<0.001) than those of the BMS-ESRD group. The SES-ESRD group had a lower 1-year major adverse cardiac events (MACE) rate than the BMS-ESRD group (6.0% vs. 33.3%; p<0.001). There were no differences in mortality and incidence of myocardial infarction between the two groups. The incidence of target vessel revascularization decreased significantly in the SES-ESRD group (2.0% vs. 19.0%, p=0.01). From a multivariate regression analysis, the use of SES was the only significant independent predictor of MACE (OR=0.054, 95% confidence interval 0.01 to 0.26, p<0.001). A comparison with SES-non ESRD group in our total registry (644 pts, 758 lesions); MACE in the SES-ESRD group (6.0%) was higher than in the SES-non ESRD group (3.1%), but there was no statistical significance (p=0.23). CONCLUSION: Compared with BMS, SES caused an improvement in the clinical outcomes in pts with ESRD.


Subject(s)
Humans , Angioplasty , Hypertension , Incidence , Kidney Failure, Chronic , Mortality , Myocardial Infarction , Stents
4.
Article in English | WPRIM (Western Pacific) | ID: wpr-23957

ABSTRACT

We report a case of ruptured mycotic aneurysm involving innominate artery requiring an urgent surgical treatment. A 62-yr-old woman presented with fever and dyspnea. Previously, she was diagnosed with colon cancer and received right hemicolectomy and one cycle of adjuvant chemotherapy. On echocardiogram, pericardial effusion was noted and emergency pericardiocentesis was performed. CT scan revealed aortic aneurysm involving ascending aorta and innominate artery, and thrombi surrounding those structures. Patch repair of the defect in the ascending aorta and ringed Goretex graft to bypass the innominate and ascending aorta were performed. We believe that this is the first case of ruptured mycotic aneurysm involving innominate artery.


Subject(s)
Female , Humans , Middle Aged , Aneurysm, Infected/surgery , Aorta/pathology , Aortic Aneurysm/surgery , Brachiocephalic Trunk/pathology , Colonic Neoplasms/drug therapy , Tomography, X-Ray Computed , Transplants
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