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1.
Artigo em Inglês | MEDLINE | ID: mdl-38083513

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is fast becoming one of the most significant infections worldwide. Of all the causes of SARS-CoV-2 infection, airborne-droplet infection via coughing is the most common. Therefore, if predicting the onset of a cough and preventing infection were possible, it would have a globally positive impact. Here, we describe a new prediction and prevention system for SARS-CoV-2 infection. Usually, air is inhaled prior to coughing, and the cough, which contains droplets of the virus, then occurs during acute exhalation. Therefore, if we can predict the onset of a cough, we can prevent the spread of SARS-CoV-2. At Tohoku University, a diagnosis system for evaluating swallowing motions and peripheral circulation has already been developed, and our prediction system can be integrated into this system. Using three-dimensional human body imaging, we developed a prediction system for preempting the onset of a cough. If we can predict the onset a cough, we can prevent the spread of SARS-CoV-2 infection, by decreasing the shower of virally active airborne droplets. Here, we describe the newly developed prediction and prevention system for SARS-CoV-2 infection that preempts the onset of a cough.Clinical Relevance- If predicting the onset of a cough and preventing infection were possible, it would have a globally positive impact. Here, we describe the newly developed prediction and prevention system for SARS-CoV-2 infection.


Assuntos
COVID-19 , Humanos , COVID-19/diagnóstico , COVID-19/prevenção & controle , COVID-19/complicações , SARS-CoV-2 , Tosse/diagnóstico , Tosse/prevenção & controle
2.
J Artif Organs ; 26(1): 12-16, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35426584

RESUMO

In this study, we developed a new catheter-mounted micro-axial flow blood pump (MFBP) using a new miniature magnetic fluid shaft seal (MFSS). The prototype of the catheter-mounted MFBP had a maximum diameter of 8 mm and a length of 50 mm. The new MFSS composed a neodymium magnet ring, an iron ring, and a magnetic fluid particularly designed for the MFSS. The new MFSS had outer and inner diameters of 4.0 mm and 2.6 mm, respectively, and a length of 3.0 mm. The sealing pressure of the MFSS was calculated to be 432 mmHg using FEM (Finite Element Method) result; therefore, the MFSS had sufficient sealing pressure for the catheter-mounted MFBP. The friction loss of the MFSS included the friction owing to the viscosity of the magnetic fluid and the magnetic force between the iron ring and ring magnet. The total friction loss of the MFSS was 0.08-0.09 W in the pump operational speed range from 22,000 to 35,000 rpm. From the in vitro experimental results, the catheter-mounted MFBP using the MFSS had a pump output of 3 L/min. against a differential pressure of 60 mmHg, and the pump characteristics of the MFBP were almost the same as those of Impella 5.0.


Assuntos
Coração Auxiliar , Magnetismo , Cateteres , Fenômenos Magnéticos , Desenho de Equipamento
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 4001-4004, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-36086215

RESUMO

The study aimed to develop a pulmonary circulatory system capable of high-speed 3D reconstruction of valve leaflets to elucidate the local hemodynamic characteristics in the valved conduits with bulging sinuses. Then a simultaneous measurement system for leaflet structure and pressure and flow characteristics was designed to obtain valve leaflet dynamic behaviour with different conduit structures. An image preprocessing method was established to obtain the three leaflets behaviour simultaneously for one sequence with two leaflets images from each pair of three high-speed cameras. Firstly, the multi-digital image correlation analyses were performed, and then the valve leaflet structure was measured under the static condition with fixed opening angles in the water-filled visualization chamber and the pulsatile flow tests simulating paediatric pulmonary flow conditions in the different types of conduit structures; with or without bulging sinuses. The results showed the maximum 3D reconstruction error to be around 0.06 mm. In the steady flow test, the evaluation of opening angles under the different flow rates conditions was achieved. In the pulsatile flow test, each leaflet's opening and closing behaviours were successfully reconstructed simultaneously at the high-frequency recording rate of 960fps. Therefore, the system developed in this study confirms the design evaluation method of an ePTFE valved conduit behaviour with leaflet structures interacting with local fluid dynamics in the vicinity of valves. Clinical Relevance- The system reveals the bulging sinus effects on ePTFE valve leaflet motion by the 3D reconstruction using multi-camera high-speed sequential imaging in vitro.


Assuntos
Próteses Valvulares Cardíacas , Politetrafluoretileno , Criança , Hemodinâmica , Humanos , Desenho de Prótese , Fluxo Pulsátil
4.
J Biomed Mater Res B Appl Biomater ; 110(11): 2387-2398, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35561095

RESUMO

There are no small-diameter, long artificial vascular grafts for below-knee bypass surgery in chronic limb-threatening ischemia. We have developed tissue-engineered vascular grafts called "Biotubes®" using a completely autologous approach called in-body tissue architecture (iBTA). This study aimed at pre-implantation evaluation of Biotube and its in vivo preparation device, Biotube Maker, for use in below-knee bypass surgery. Forty nine makers were subcutaneously embedded into 17 goats for predetermined periods (1, 2, or 3 months). All makers produced Biotubes as designed without inflammation over all periods, with the exception of a few cases with minor defects (success rate: 94%). Small hole formation occurred in only a few cases. All Biotubes obtained had an inner diameter of 4 mm and a length of 51 to 52 cm with a wall thickness of 594 ± 97 µm. All Biotubes did not kink when completely bent under an internal pressure of 100 mmHg and did not leak without any deformation under a water pressure of 200 mmHg. Their burst strength was 2409 ± 473 mmHg, and suture retention strength was 1.75 ± 0.27 N, regardless of the embedding period, whereas tensile strength increased from 7.5 ± 1.3 N at 1 month to 9.7 ± 2.0 N at 3 months with the embedding period. The amount of water leakage from the needle holes prepared in the Biotube wall was approximately 1/7th of that in expanded polytetrafluoroethylene vascular grafts. The Biotubes could be easily connected to each other without cutting or anastomosis leaks. They could be stored for at least 1 year at room temperature. This study confirmed that even Biotubes formed 1 month after embedding of Biotube Makers had properties comparable to arteries.


Assuntos
Implante de Prótese Vascular , Cabras , Animais , Prótese Vascular , Politetrafluoretileno , Engenharia Tecidual , Água
5.
EJVES Vasc Forum ; 54: 27-35, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35128505

RESUMO

OBJECTIVE: There is a need for small diameter vascular substitutes in the absence of available autologous material. A small diameter, long tissue engineered vascular graft was developed using a completely autologous approach called "in body tissue architecture technology (iBTA)". The aim of this pilot study was to evaluate "Biotubes", iBTA induced autologous collagenous tubes, for their potential use as small diameter vascular bypass conduits. METHODS: Biotubes (internal diameter 4 mm, length 50 cm, wall thickness 0.85 mm) were prepared by subcutaneous embedding of plastic moulds (Biotube Maker) in three goats for approximately two months. Allogenic Biotubes (length 10 cm [n = 2], 15 cm [n = 2], 22 cm [n = 2]) were bypassed to both carotid arteries by end to side anastomosis with their ligation between the anastomoses in another three goats. Residual Biotubes were examined for their mechanical properties. After four weeks, the harvested Biotubes were evaluated histologically. RESULTS: All Biotubes had sufficient pressure resistance, approximately 3000 mmHg. Although wall thickening occurred at two proximal anastomosis sites, all six grafts were patent without luminal thrombus formation, stenosis, or aneurysm deformation throughout the implantation period. Endothelial cells covered both anastomosis sites almost completely, with partial covering in the central portion of the grafts. Furthermore, α smooth muscle actin positive cells infiltrated the middle layer along almost the entire graft length. CONCLUSION: This preliminary study showed that small diameter, long, tissue engineered Biotubes could function properly as arterial bypass conduits in a large animal for one month without any abnormal change in vascular shape. Thus, small diameter, long Biotubes are potentially viable conduits, which are biocompatible and labour non-intensive, and therefore, suitable for clinical practice. Additionally, Biotubes can start the regeneration process in a short period of time.

6.
Heart Vessels ; 37(5): 794-801, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34677657

RESUMO

Factors causing atrial tachyarrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF) remain undetermined. This study aimed to investigate the effect of nocturnal hypoxemia on the recurrence of atrial tachyarrhythmia after CA of AF. Among 594 patients with AF who underwent an ambulatory sleep study at the National Cerebral and Cardiovascular Center, Suita, Osaka, Japan (2014-2019), 365 underwent CA of AF; 290 patients who underwent CA were followed up for > 3 months. Multivariate Cox regression analysis was used to calculate hazard ratios (HRs) using clinical variables, to identify the independent predictors of atrial tachyarrhythmia recurrence after the final CA. Atrial tachyarrhythmia recurred in 45 of 290 (15.5%) patients during the median follow-up period of 479 days (interquartile range 225-1002). On the performing multivariate analysis of the data of patients who did not receive continuous positive airway pressure (CPAP), severe nocturnal hypoxemia [defined as the percentage of sleep time spent with SaO2 of < 90% (T90) over 20%] [HR 8.53, 95% confidence interval (CI) 1.872-38.814; P < 0.01] and an 1 mL/m2 increase in the left atrial volume index (HR 1.02, 95% CI 1.004-1.044; P = 0.02) were found to be independently associated with the recurrence of atrial tachyarrhythmia. In addition, the rates of freedom from atrial tachyarrhythmia after the final AF ablation with CPAP were significantly lower in the group with more severe nocturnal hypoxemia (Log-rank P = 0.03). In conclusion, it is necessary to consider both, AHI and nocturnal hypoxia while performing an ambulatory sleep apnea study. CA may be less effective in patients with more severe nocturnal hypoxia, despite the administration of CPAP.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Fibrilação Atrial/complicações , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Ablação por Cateter/efeitos adversos , Átrios do Coração , Humanos , Hipóxia/complicações , Recidiva , Fatores de Risco , Taquicardia/complicações , Taquicardia/cirurgia , Resultado do Tratamento
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 1573-1576, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34891585

RESUMO

Dysphasia is one of the complications which may cause functional disability after the surgical treatment of oral cancer. The loss of the function derived by tongue and other oral tissues impairs the retention and delivery of liquids and food masses as well as the swallowing motion into pharynx. As accumulation of liquids or food masses in the larynx can lead to pneumonia, therefore swallowing support to improve each coordination of the tongue, the epiglottis and the esophagus in the process of swallowing is highly desirable. In this study, we designed a new artificial tongue which was capable of contracting to deliver the bolus masses in the swallowing propulsion phase in the oral cavity. We designed a two-layered artificial tongue simulating the anatomical identical muscle structures with the longitudinal muscle, and the transverse muscle-genioglossus layer. A silicone rubber material was used for the surface layer, and the covalent shape memory alloy fibers (diameter: 150µm) were implemented in the secondary structure beneath of the silicone rubber material of the artificial tongue. Its contraction was driven by with shape memory alloy fibers shortage inside of the artificial tongue unit. The actuation was accurately controlled by the originally designed electrical current input with pulse width modulation. Firstly, we examined a prototype structure of the artificial tongue as well as the changes in unit thickness as it constricted by electric power supply switching. Secondly, we performed a feasibility study of the prototype into the head-neck medical training model with larynx-tracheal structure with esophagus. The results were as follows: a) the artificial tongue model showed a large contraction with a motion to increase upward pressure, b) the tongue unit expressed the capability of reducing shallow space between dorsal tongue surface and palate in the oral cavity model. Therefore, the first artificial tongue design with active contractile motion will be useful orally installable device for improving delivery function of bolus masses through swallowing procedure in dysphasia.Clinical Relevance- The active artificial tongue system designed for the first time exhibited an effective contractile motion to support bolus food masses propulsion in swallowing process in the oral cavity in the patients with dysphasia.


Assuntos
Ligas de Memória da Forma , Língua , Deglutição , Humanos , Boca , Faringe
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 7206-7210, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34892762

RESUMO

We have been developing an implantable power generation system that uses muscle contraction following electrical stimulation as a permanent power source for small implantable medical devices. However, if the muscle tissue is overloaded for power generation, the tissue may rupture or blood flow may be impaired. In this study, we developed a new muscle-connecting component that solves these problems. The new connection device has three rods attached to the muscle fibers, and the force exerted on the muscle fibers is converted from horizontal to vertical when the muscle contracts. We conducted simulations with a three-dimensional (3D) model, as well as pulse wave muscle measurements and in vivo tests using the actual muscle. The pulse wave in the connecting part and its downstream were optically measured from the muscle surface, and the blood flow was not obstructed. The 3D model simulations revealed that the distribution of stress was preferable compared with the case in which a rod was stuck vertically in the muscle. In the in vivo muscle tests, the metal rod and resin parts were attached to the muscle, and a load of up to approximately 9 N was applied to the connecting part. Consequently, the connecting part was stable and integrated with the muscle, and there was no damage in the muscle. Although no long-term or histological evaluations were conducted, the device may be useful because of the intramuscular power generation owing to the minimal load applied on the part connected with the muscle.


Assuntos
Contração Muscular , Próteses e Implantes , Estimulação Elétrica , Fibras Musculares Esqueléticas
9.
Heart Vessels ; 36(5): 675-685, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33580804

RESUMO

Atrial tachycardia (AT) and atrial fibrillation (AF) commonly occur after cardiac surgeries (CSs). This study investigated the mechanisms and long-term outcomes of AT and AF ablation after various Maze procedures, particularly whether atrial tachyarrhythmias after the Maze procedure occur due to gaps in the Maze lines. We analyzed 37 consecutive cases with atrial tachyarrhythmias after the Maze procedures and concomitant CSs between 2007 and 2019. Fifty-nine atrial tachyarrhythmias were induced in 37 consecutive cases, and 49 of those atrial tachyarrhythmias were mappable ATs. Forty ATs were related to the Maze procedures in the 49 mappable ATs (81.6%). All 37 consecutive cases had residual electrical conductions (gaps) in the Maze lines (88 gaps; 2.4 ± 1.2 gaps/patient). Forty of 88 gaps (45.5%) were associated with gap-related ATs. The common ATs in this study were 1. peri-mitral atrial flutter due to gaps at pulmonary vein isolation (PVI) line to mitral valve annulus (MVA) (20 cases), and 2. peri-tricuspid atrial flutter due to gaps at right atrial incision to the tricuspid valve annulus (TVA) (10 cases). Forty-seven of 49 ATs (95.9%) were successfully ablated at the first session, and there were no complications. The mean follow-up period after ablation was 3.6 ± 3.2 (median, 2.1; interquartile range, 0.89-6.84) years. The Kaplan-Meier analysis of freedom from recurrent atrial tachyarrhythmias after Maze procedure was 82.7% at 1-year follow-up and 75.5% at 4-year follow-up after a single procedure. Reentry was the main mechanism of ATs after Maze procedures and concomitant CSs, and ATs were largely related to the gaps on the Maze lines between the PVI line and the MVA or those on the lines between right atrial incision to the TVA. Long-term follow-up data suggest that catheter ablation of atrial tachyarrhythmias after various Maze procedures is effective and safe.


Assuntos
Fibrilação Atrial/cirurgia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Ablação por Cateter/efeitos adversos , Átrios do Coração/fisiopatologia , Veias Pulmonares/cirurgia , Idoso , Fibrilação Atrial/etiologia , Fibrilação Atrial/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Recidiva , Estudos Retrospectivos , Resultado do Tratamento
10.
Sci Rep ; 11(1): 3830, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589686

RESUMO

Reflected wave increases after endovascular aortic repair (EVAR) in patients with aortic aneurysm. This affects the left ventricular (LV) diastolic function and leads to a poor prognosis. This study aimed to evaluate the relationship between increased reflected wave amplitude and aortic diameter after EVAR. EVAR was performed in seven healthy goats. We assessed wave intensity (WI), aortic diameter, and stiffness parameter ß. Moreover, we evaluated the relationship between negative reflected wave (NW, reflected waves toward the heart from the periphery by WI) and other parameters after EVAR. Results showed an increase in stiffness parameter ß (3.5 ± 0.3 vs 15.9 ± 4.7, p = 0.018) and a decrease in the change of aortic diameter (6.9 ± 0.7 vs 2.7 ± 0.4%, p = 0.018) after EVAR. The NW was significantly amplified after EVAR from baseline (-589.8 ± 143.4 to - 1192.3 ± 303.7 mmHg-m/sec3, p = 0.043). The NW showed a significant correlation with maximum aortic diameter (R = 0.707, p = 0.038) and minimum aortic diameter (R = 0.724, p = 0.033). The reflected wave was enhanced after EVAR and was correlated to the aortic diameter at the stent-graft site. It is important to consider that patients with smaller aortic diameters in landing zone who undergo EVAR may develop LV dysfunction.


Assuntos
Aorta/diagnóstico por imagem , Aorta/patologia , Aneurisma Aórtico/diagnóstico , Diagnóstico por Imagem , Animais , Aorta/fisiopatologia , Aorta/cirurgia , Aneurisma Aórtico/cirurgia , Biomarcadores , Diagnóstico por Imagem/métodos , Modelos Animais de Doenças , Eletrocardiografia , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/métodos , Feminino , Cabras , Testes de Função Cardíaca , Hemodinâmica , Período Pós-Operatório , Stents , Ultrassonografia/métodos , Rigidez Vascular
11.
J Artif Organs ; 24(2): 111-119, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33559766

RESUMO

Chronic blood trauma caused by the shear stresses generated by mechanical circulatory support (MCS) systems is one of the major concerns to be considered during the development of ventricular assist devices. Large multimers with high-molecular-weight von Willebrand factor (VWF) are extended by the fluid forces in a shear flow and are cleaved by ADAMTS13. Since the mechanical revolving motions in artificial MCSs induce cleavage in large VWF multimers, nonsurgical bleeding associated with the MCS is likely to occur after mechanical hemodynamic support. In this study, the shear stress (~ 600 Pa) and exposure time related to hemolysis and VWF degradation were investigated using a newly designed mechanical shuttle shear flow tester. The device consisted of a pair of cylinders facing the test section of a small-sized pipe; both the cylinders were connected to composite mechanical heads with a sliding-sleeve structure for axial separation during the withdrawing motion. The influence of exposure time, in terms of the number of stress cycles, on hemolysis and VWF degradation was confirmed using fresh goat blood, and the differences in the rates of dissipation of the multimers were established. The plasma-free hemoglobin levels showed a logarithmic increase corresponding to the number of cycles, and the dissipation of large VWF multimers occurred within a few seconds under high shear stress flow conditions.


Assuntos
Proteína ADAMTS13/metabolismo , Coração Auxiliar/efeitos adversos , Hemólise , Estresse Mecânico , Fator de von Willebrand/metabolismo , Animais , Cabras , Hemodinâmica , Hemorragia
12.
J Artif Organs ; 24(1): 27-35, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32930908

RESUMO

In roller pumps used for cardiopulmonary bypass (CPB), the degree of blockage within the tube resulting from compression of the tube by the rollers, or the degree of occlusion, is closely related to hemolysis, with both tight occlusive and non-occlusive degrees promoting hemolysis. There are as yet no international standards regarding methods of adjusting occlusiveness, and the amount of mechanical stress exerted upon blood remains unknown. To prevent hemolysis during CPB using roller pumps, there is a need to clarify and quantitatively assess the mechanical stress of the occlusiveness of the roller pump. In this study, we have developed a degree of occlusion quantification system which constructs the flow channel shape within an occluded tube from red optical density images, and we have verified the validity of this system. Utilizing a linear actuator, an acrylic roller and raceway, a solution colored with simulated blood powder, and a 3/8-inch vinyl chloride tube, this system uses a camera to capture red optical density images within an occluded tube and constructs the tube flow channel shape using a formula manipulation system. To verify the accuracy of this system, we compared the thickness of a cross-section of the flow channel constructed with the degree of occlusion quantification system with the thickness of a cross-section of silicone cured under the same occlusion conditions. Our experiments indicated that for areas with a small tube gap, this system can construct highly accurate three-dimensional shapes and obtain quantitative indicators assessing the degree of occlusion.


Assuntos
Ponte Cardiopulmonar/instrumentação , Dispositivos Ópticos , Hemólise , Humanos , Estresse Mecânico
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5008-5011, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019111

RESUMO

Repair of dissected aorta requires remodeling the structure of the media. Modeling approaches specific to endovascular stenting for aortic dissection have been reported. We created a goat model of descending thoracic aortic dissection and reproduced its morphological characteristics in a mock circulatory system. The purpose of this study was to examine a newly developed aortic stent which was capable of installing to the aortic dissected lesion for biomedical hemodynamics point of view. In this study, we examined the changes in hemodynamics of dissected lesions and the amelioration by endovascular stent intervention. Firstly, we performed animal experiments with the dissected aorta and examined the effects of stenting on volumetric changes in the false lumen. Secondly, we made several types of 3-D stereolithographic dissected aortic models with silicone rubber membrane between the false and the true lumens. Then, the hemodynamic characteristics in each model were evaluated in the pulsatile flow conditions in a mock circulatory system. These modelling approaches enabled the quantitative examination of post-therapeutic effects of stenting followed by elucidating of hemodynamic changes in the vicinity of stents, which may follow the management of clinical amelioration of interventional treatment with aortic stenting.Clinical Relevance- This study represents a modelling approach of the dissected aorta for endovascular intervention using stenting followed by the examination of false lumen volumetric changes resulting in the deterioration of pressure increase in diseased lesions.


Assuntos
Aneurisma da Aorta Torácica , Dissecção Aórtica , Dissecção Aórtica/cirurgia , Animais , Aorta , Aneurisma da Aorta Torácica/cirurgia , Hemodinâmica , Stents
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5097-6100, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019133

RESUMO

Rotary blood pump (RP) is one of the most important devices in the treatment of profound heart failure and is known to reduce the pulse in the blood pressure waveform, especially when it is used for axial flow. In an outpatient clinic, checking the pulse of a patient implanted with an RP can help diagnose the patient's condition. For that purpose, animal experiments with healthy adult goats implanted with the EVAHEART system were carried out after obtaining ethical committee approval. Visual imaging of the goats' faces was recorded using a video camera. The pulse waves were clearly recorded using the newly developed pulse diagnosis system with video imaging and compared with laser Doppler flowmeter and time series data. Spectral analysis of the time series data showed the usefulness of video imaging from outside the body. Clinical applications are planned, and this newly developed method is expected to be a useful diagnostic method for evaluating the cardiac function in patients implanted with RPs in the future.


Assuntos
Coração Auxiliar , Instituições de Assistência Ambulatorial , Animais , Pressão Sanguínea , Frequência Cardíaca , Humanos , Fluxo Pulsátil
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5128-5131, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019140

RESUMO

With the progress of surgical technology, the survival rate after resection of esophageal and tongue carcinomas has improved. However, the surgical protocol for esophageal and tongue surgery is complex, and surgery for elderly esophageal and tongue carcinoma patients with cardiopulmonary dysfunction is difficult. Using an artificial tongue and esophagus will be helpful for patients. However, peristalsis of foods depends on food size, taste, and viscosity. This study developed and evaluated a new diagnosis machine for drinking and peristalsis motion. Before clinical evaluation, animal experiments were performed on healthy adult goats using a stereo camera. After a feasibility study of the diagnosis system for peristalsis, clinical evaluation was conducted on healthy normal volunteers. We observed no aspiration pneumonia. The foods and drinks tested were safe. There was no mis-swallowing, but the participants' feeling with regard to taste differed. Overall, the results indicated that the quantitative swallowing and peristalsis diagnosis system is safe. Evaluation of the visual imaging and spectral analysis gave us useful information about peristalsis, which will help us design an artificial tongue and esophagus with a good control mechanism in the near future.


Assuntos
Deglutição , Peristaltismo , Idoso , Animais , Ingestão de Líquidos , Esôfago/diagnóstico por imagem , Humanos , Língua
17.
J Physiol Anthropol ; 39(1): 21, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32811571

RESUMO

With the popularization of pulse wave signals by the spread of wearable watch devices incorporating photoplethysmography (PPG) sensors, many studies are reporting the accuracy of pulse rate variability (PRV) as a surrogate of heart rate variability (HRV). However, the authors are concerned about their research paradigm based on the assumption that PRV is a biomarker that reflects the same biological properties as HRV. Because PPG pulse wave and ECG R wave both reflect the periodic beating of the heart, pulse rate and heart rate should be equal, but it does not guarantee that the respective variabilities are also the same. The process from ECG R wave to PPG pulse wave involves several transformation steps of physical properties, such as those of electromechanical coupling and conversions from force to volume, volume to pressure, pressure impulse to wave, pressure wave to volume, and volume to light intensity. In fact, there is concreate evidence that shows discrepancy between PRV and HRV, such as that demonstrating the presence of PRV in the absence of HRV, differences in PRV with measurement sites, and differing effects of body posture and exercise between them. Our observations in adult patients with an implanted cardiac pacemaker also indicate that fluctuations in R-R intervals, pulse transit time, and pulse intervals are modulated differently by autonomic functions, respiration, and other factors. The authors suggest that it is more appropriate to recognize PRV as a different biomarker than HRV. Although HRV is a major determinant of PRV, PRV is caused by many other sources of variability, which could contain useful biomedical information that is neither error nor noise.


Assuntos
Frequência Cardíaca/fisiologia , Fotopletismografia/métodos , Idoso de 80 Anos ou mais , Biomarcadores , Feminino , Humanos , Postura/fisiologia , Processamento de Sinais Assistido por Computador
18.
Artif Organs ; 44(10): 1067-1072, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32216103

RESUMO

In this study, we developed a trans-valve left ventricular assist device (LVAD) that unites a rear-impeller axial-flow blood pump (AFBP) and a polymer membrane valve placed at the aortic valve position. The diameter and length of the rear impeller AFBP was 12 and 63 mm, respectively. The polymer membrane valve was similar to the jelly-fish valve consisting of a valve leaflet made of silicone rubber (thickness 0.5 mm), valve ring (diameter: 25 mm), and valve spokes. The trans-valve LVAD was examined in a mock circulation. An implantable pulsatile flow (PF) VAD was connected to an atrial reservoir to simulate the left ventricle (LV), and the Hall valve was worn in the inflow port, and the trans-valve LVAD was placed in the outflow port as an outflow valve. When the motor rotational speed increased to 26 400 rpm, the mean aortic flow increased from 4.2 to 5.3 L/min, mean aortic pressure increased from 83.4 to 100 mm Hg, and mean motor current of the implantable PF VAD decreased from 1.18 to 0.94 A (unloading effect on LV -21%). The energy equivalent pressure increased from 85.2 to 102 mm Hg, and surplus hemodynamic energy (SHE) decreased by -15.4% from the baseline. In conclusion, the trans-valve LVAD has an advantage of preserving pulsatility without any complicated mechanism and is a novel and promising LV support device.


Assuntos
Coração Auxiliar/efeitos adversos , Desenho de Prótese , Implantação de Prótese/métodos , Fluxo Pulsátil/fisiologia , Disfunção Ventricular Esquerda/cirurgia , Valva Aórtica/fisiologia , Valva Aórtica/cirurgia , Humanos , Implantação de Prótese/instrumentação , Função Ventricular/fisiologia
19.
Artif Organs ; 43(9): 828-833, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31013366

RESUMO

In this study, rear-impeller axial flow blood pumps (RIAFBP) were developed to realize a trans-valve axial ventricular assist device (VAD) which consists of the latter blood pump and a polymer monomembrane aortic valve, such as the jellyfish valve. The motor of the RIAFBP is installed in the left ventricle, and its impeller is placed at the aortic valve position. In the prototype RIAFBP, the rotation of the motor is sustained by polyethylene bushings. The RIAFBP has a length of 50 mm and diameter of 19.6 mm. The miniature RIAFBP has the same construction as that of the prototype; however, it employs a ceramic bearing and fin bearing to improve endurance and to reduce blood stagnation. The miniature RIAFBP has a length of 63 mm and diameter of 12 mm. Both RIAFBPs were examined by an in vitro experiment using a 33% glycerin solution. The prototype RIAFBP achieved a maximum pump outflow of 8.5 L/min against a pump head of 100 mm Hg at a rotational speed of 12 000 rpm. The miniature RIAFBP achieved 7 L/min against a pump head of 70 mm Hg at a rotational speed of 21 600 rpm. In conclusion, the miniature RIAFBP has enough pump performance to realize the trans-valve axial VAD.


Assuntos
Coração Auxiliar , Valva Aórtica/cirurgia , Ventrículos do Coração/cirurgia , Hemodinâmica , Humanos , Desenho de Prótese
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 1448-1451, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31946166

RESUMO

Your heart rate and blood pressure are respond to the curve, slope, lane width, and road surface friction coefficient of the expressway design. However, no report was reported concerning about the Expressway design from the viewpoint of medical information of the driver until now. To prevent the traffic accident, human factor is of course one of the most important factors. In this study, the Cloud Database Construction for the Expressway Design by the use of the Medical Information had been tried to carry out. HR response and PWV responses had been tried to be analyzed by the sensors in the car during driving. LF, HF and LF/HF of Heart rate variability had been calculated and tagged with expressway information including left and right curve, slope, lane width, and road surface friction coefficient. Furthermore, pulse of the descending aorta had been tried to be recorded from the sensor in a driver seat, so, the pulse wave velocity and blood pressure could be evaluated. Recording system of an Eye movement, pupil diameter, cerebral blood flow, and EEG are now under construction. So, all human driver's data will be combined in the Cloud of the Central office. this method will be useful for the development of the designing method the Expressway in near future.


Assuntos
Condução de Veículo , Bases de Dados Factuais , Acidentes de Trânsito , Movimentos Oculares , Humanos , Análise de Onda de Pulso
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