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1.
Aktuelle Urol ; 41 Suppl 1: S24-6, 2010 Jan.
Article in English | MEDLINE | ID: mdl-20094947

ABSTRACT

INTRODUCTION: We evaluated the effects of intra-vesical injection of botulinum toxin type A in the detrusor muscle in patients with neurogenic overactive bladder (OAB), patients with non-neurogenic overactive bladder and patients with interstitial cystitis. MATERIALS AND METHODS: Between January 2003 and December 2006 we treated 30 patients with 100 I. U. to 300 I. U. of botulinum toxin A in the detrusor muscle. Patients were clinically and urodynamically followed up for 4, 12 and 36 weeks thereafter. RESULTS: Neurogenic overactive bladder: of the 19 injected doses, 18 (94.7%) in 7 patients were judged as effective, and 1 (5.2%) of 200 U of BTX-A was judged as ineffective. Mean bladder volume increased from 137 to 396 ml. Non-neurogenic overactive bladder: of 7 injections, 6 (85.7%) were judged effective in 5 patients. Mean bladder volume increased from 149 to 322 ml. Interstitial cystitis: in all 4 patients the treatments were deemed ineffective. CONCLUSIONS: Injecting 300 units of BTX-A into 30 sites in the muscle located in the body of the bladder region is effective for neurogenic bladder patients with intermittent catheterization who have urge and reflective types of incontinence. Injections of 100 and 200 units of BTX-A to treat non-neurogenic overactive bladder with urinary incontinence provided together without retention. The optimal dose of BTX-A requires further investigation. Injection with 200 units of BTX-A was not useful against interstitial cystitis. None of the patients developed any adverse effects after injecting the bladder wall with BTX-A.


Subject(s)
Botulinum Toxins, Type A/administration & dosage , Urinary Bladder, Neurogenic/drug therapy , Urinary Bladder, Overactive/drug therapy , Urinary Incontinence/drug therapy , Adolescent , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Injections, Intramuscular , Male , Middle Aged , Urinary Bladder/drug effects , Urodynamics/drug effects
2.
Artif Organs ; 27(2): 184-8, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12580777

ABSTRACT

The purpose of this study was to demonstrate the feasibility of the use of an implantable, high-energy, and compact battery system for an undulation pump total artificial heart (UPTAH). The implantable battery system tested consists of six lithium-ion batteries in series, a charge unit, and a charge/discharge control unit. A lithium-ion battery is currently the best energy-storage device because it has more energy density, a better life cycle, and a smaller temperature rise than those of other secondary batteries. The performance of the implantable battery system was evaluated in an in vitro experiment using an electric load that simulated the UPTAH. Also, sufficiently reliable operation of a system for supplying energy to a UPTAH consisting of a transcutaneous energy transmission system (TETS) and an implantable battery system was confirmed in three experiments using goats. The results of the in vitro and in vivo experiments showed that the implantable battery system supplied sufficient current to the UPTAH for maintenance of physiological conditions in the goat with maximum rise in temperature to less than 43 degrees C.


Subject(s)
Electric Power Supplies , Heart, Artificial , Animals , Equipment Design , Feasibility Studies , Goats , Male , Prostheses and Implants
3.
Artif Organs ; 27(1): 73-7, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12534716

ABSTRACT

The prototype of the miniature vibrating flow pump (VFP) is developed for the external shunt catheter. The cross-slider mechanism is applied to vibrate the tube, which causes the pumping effect. This mechanism results in successful development of the miniature and lightweight VFP. By the use of the prototype VFP, the experiment of the basic pump performance is made in detail based on the authorized procedure in the research field of fluids engineering. The typical H-Q curve of VFP, which is the relationship between the pump head and the flow rate, can be obtained. This result suggests that the miniature VFP developed here can be expected to be used as the booster pump for the external shunt catheter in clinical applications.


Subject(s)
Arteriovenous Shunt, Surgical/instrumentation , Cardiac Catheterization/instrumentation , Coronary Artery Bypass/instrumentation , Heart-Assist Devices , Myocardial Ischemia/prevention & control , Vibration , Coronary Circulation/physiology , Hemodynamics/physiology , Hemorheology , Humans , Models, Cardiovascular , Myocardial Ischemia/physiopathology , Prosthesis Design
4.
Artif Organs ; 27(1): 114-8, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12534723

ABSTRACT

Aiming to observe directly the microcirculation after total artificial heart (TAH) implantation, we performed a long-term follow-up in 2 goats using conjunctival angioscopy. A short segment of parallel arteriole and venule was photographed and analyzed on computer picture program (magnification 40x). Three main parameters were measured: arteriole diameter, venule diameter, and arteriovenous ratio (A/V ratio). The intrathoracically implanted TAH was the undulation pump total artificial heart (UPTAH) with cardiac output of 100 ml/kg/min. To stabilize the peripheral hemodynamics a 1/R biofeedback control system was used. Our results provided only elementary data about morphology of bulbar microvessels. The main finding was the tendency to general vasoconstriction, more intensive on the venous side (*P < 0.05 in one goat). We did not observe any pathological shapes (e.g., tortuosities, varicosities, or sludge); this result could be attributed to the high effectivity of 1/R control method. These preliminary results should be considered only as an attempt to apply the widely used clinical method of conjunctival angioscopy to the conditions of TAH.


Subject(s)
Conjunctiva/blood supply , Conjunctiva/physiopathology , Heart, Artificial/adverse effects , Microcirculation/physiology , Microscopic Angioscopy , Postoperative Complications , Prosthesis Implantation/adverse effects , Animals , Arterioles/pathology , Arterioles/physiopathology , Conjunctiva/pathology , Disease Models, Animal , Follow-Up Studies , Goats , Hemodynamics/physiology , Time Factors , Vasoconstriction/physiology , Venules/pathology , Venules/physiopathology
5.
J Biol Chem ; 276(24): 21863-9, 2001 Jun 15.
Article in English | MEDLINE | ID: mdl-11274141

ABSTRACT

The yeast AP-1-like transcription factor, Yap1p, is essential for the oxidative stress response in budding yeast. Yap1p is located predominantly in the cytoplasm; however, upon imposition of oxidative stress, Yap1p concentrates in the nucleus and activates target genes. Yap1p is constitutively transported in and out of the nucleus. Oxidative stress inhibits the Crm1p/Xpo1p-dependent nuclear export step, resulting in nuclear accumulation of Yap1p. In this study, we examined the mechanism for Yap1p nuclear import, and determined whether the import step is affected by oxidative stress. The nuclear accumulation of Yap1p required the activity of the small GTPase, Ran/Gsp1p. Under conditions in pse1-1 cells carrying a temperature-sensitive mutation of the importin beta family member PSE1/KAP121, nuclear translocation of Yap1p was inhibited dramatically. In an in vitro assay, we showed that Yap1p could directly bind to Pse1p and that this interaction was dissociated by Ran-GTP. These results indicate that Pse1p is the nuclear import receptor for Yap1p. In addition to Pse1p, we suggest that Kap123p, which is homologous to Pse1p, has a minor effect on the nuclear import of Yap1p. Furthermore, we identified the nuclear localization signal of Yap1p and demonstrated that the nuclear import of Yap1p was not affected by oxidative stress.


Subject(s)
Cell Nucleus/metabolism , DNA-Binding Proteins/metabolism , Membrane Transport Proteins , Oxidative Stress , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Transcription Factors/metabolism , Fungal Proteins/metabolism , Gene Expression Regulation, Fungal , Genotype , Monomeric GTP-Binding Proteins/metabolism , Nuclear Proteins/metabolism , Protein Transport , ran GTP-Binding Protein/metabolism
6.
Artif Organs ; 25(1): 69-71, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11167565

ABSTRACT

The undulation pump is a small continuous flow displacement-type blood pump. The undulation pump total artificial heart (UPTAH) is a unique implantable total artificial heart using undulation pumps. An adult female goat weighing 45.8 kg was used for implantation. The natural heart was replaced with the UPTAH under extracorporal circulation. The cardiac output (CO) was maintained to 100 ml/kg/min by controlling the right pump manually. To prevent lung edema, the left pump was controlled automatically to maintain the left atrial pressure below 20 mm Hg. The CO was maintained for 2 weeks. Thereafter, the CO gradually decreased. The goat suddenly died because of a brain stroke on the 31st postoperative day. At autopsy, the cavity of the left atrial cuff was almost occupied by the big pannus-like thrombus, which was thought to be the cause of death. Improvement of the atrial cuff is necessary to obtain longer survival and is being modified. No thrombus was found inside the pumps. However, temperature rise in a left motor was a problem. Improvement of the efficiency in a motor is necessary. Although many problems still remained, 1 month survival could be obtained with this unique implantable TAH using continuous flow displacement-type blood pumps.


Subject(s)
Heart, Artificial , Hemodynamics , Animals , Cardiac Output , Female , Goats , Heart, Artificial/adverse effects , Prosthesis Design , Thrombosis/etiology
7.
Artif Organs ; 24(8): 656-8, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10971257

ABSTRACT

Research of the distributed artificial heart is important not only to acquire the means of individual organ perfusion but also to clarify the characteristics of the organ and the mechanism of blood distribution. To investigate the distributed artificial heart, the miniature undulation pump was developed. The outer diameter and the thickness of the developed pump were 38 mm and 11 mm, respectively. The priming volume of the pump was 3.2 ml. The total size including the motor unit was 38 mm in diameter and 32 mm in length. The total weight was 67.5 g. The total volume was 27.5 ml. The pump was driven with pulse width modulation by using a 1 chip motor controller. More than 5 L/min of continuous output could be obtained. The results showed that the developed miniature undulation pump system had enough performance for individual organ perfusion.


Subject(s)
Heart, Artificial , Biomechanical Phenomena , Durable Medical Equipment , Equipment Design , Humans , Miniaturization , Polyurethanes
8.
Artif Organs ; 24(8): 680-2, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10971262

ABSTRACT

Separate systemic circulations with pulsatile flow were obtained using 1 rotary blood pump as a left ventricular assist device. The outlet of the pump was divided into 2 conduits, 1 connected to the upper half of the body and the other connected to the lower half. An electric actuator that clamped the 2 outlet conduits alternately provided pulsatile flows. An in vitro experiment showed that the pulsatility phases of the upper and lower halves of the body were complementary with pulsatile flow, and an in vivo experiment showed that controlled flow distributions of continuous flows could be obtained.


Subject(s)
Heart-Assist Devices , Pulsatile Flow , Animals , Blood Flow Velocity , Centrifugation , Equipment Design , Goats , Hemodynamics
9.
ASAIO J ; 46(4): 500-4, 2000.
Article in English | MEDLINE | ID: mdl-10926154

ABSTRACT

An undulation pump is a special rotary blood pump in which rotation of a brushless DC motor is transformed to an undulating motion by a disc in the pump housing attached by means of a special link mechanism. In the blood pump, a closed line between the disc and housing moves from the inlet to the outlet by this undulating disc motion, which sucks and pushes the blood from the inlet to the outlet. Because the same phenomena occurs at both sides of the disc, a continuous flow is obtained when the motor rotational speed is constant. The pump flow pattern can be easily changed from continuous flow to pulsatile flow by controlling the motor drive current pattern. A seal membrane made of segmented polyurethane protects the blood from invading the link mechanism as well as the motor. UPTAH is fabricated with two undulation pumps and two brushless DC motors. Its size is 75 mm in diameter and 80 mm long, and it has one of the great advantage of no compliance chamber required in the system. UPTAHs were implanted under cardiopulmonary bypass (CPB) into the chest cavities of 16 goats, each weighing between 41 and 72 kg. No anticoagulant and antiplatelet agent was used after the surgery. The left atrial pressure was automatically controlled to prevent its elevation and sucking of the atrial wall into the atrial cuff. The following results were obtained: (1) UPTAHs fit well into all the goats; (2) the longest survival was 19.8 days, the cause of death was bleeding from the aortic anastomosis; (3) No thrombus was observed in the blood pump despite no anticoagulant use. Hemolysis depended upon the length of CPB during surgery. When CPB time was within 2 hours, hemolysis level returned to baseline within a few days of the surgery. UPTAH is a promising implantable TAH, because of its small size and easy controllability.


Subject(s)
Heart, Artificial , Animals , Female , Goats , Hematocrit , Hemoglobins/analysis , Time Factors
10.
Artif Organs ; 24(4): 312-5, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10816207

ABSTRACT

A conductance and arterial pressure based method (1/R control) to determine the cardiac output (CO) of a total artificial heart (TAH) was developed to provide a central nervous system with control over the output of TAH. In order to clarify the deference in hemodynamic response between natural heart and 1/R control, biventricular bypass was introduced in the goat. After 2 pneumatically driven sac-type blood pumps were connected to the natural heart, the pulmonary artery was totally clamped to acquire 100% right heart bypass, and the ascending aorta was stenosed to acquire about 60 to 90% left heart bypass; 1/R control was performed substituting the output of the right artificial heart for the CO. The results demonstrated that stable control could be achieved. A discrepancy was often seen between the pulse rate (PR) of the artificial heart and the heart rate (HR) in absolute value. However, the relative changes of PR were quite similar to that of HR for the most part, indicating that the responses of 1/R control were the duplication of natural cardiac responses in normal daily activity.


Subject(s)
Blood Pressure/physiology , Cardiac Output/physiology , Heart Rate/physiology , Heart, Artificial , Hemodynamics/physiology , Animals , Aortic Valve Stenosis/physiopathology , Atrial Function, Right/physiology , Female , Goats , Pulmonary Artery/physiopathology , Pulse , Stroke Volume/physiology
11.
Gan To Kagaku Ryoho ; 27(2): 285-8, 2000 Feb.
Article in Japanese | MEDLINE | ID: mdl-10700902

ABSTRACT

The patient was a 57-year-old man abnormalities indicated in examinations by X-ray and ultrasonography in February, 1991. X-ray and endoscopic examination revealed a Borrmann type 3 carcinoma in the posterior wall and lesser curvature of the upper body of the stomach. The liver was swollen to 3 fingerbreadths on the right mid-clavicular line. Multiple liver metastases were revealed by computed tomography (CT). Proximal gastrectomy was done. From March 24, 1991, a Futraful suppository (1,500 mg/day) was given daily. After 4 months, CT showed the reduction and partial disappearance of the low-density areas of the liver. After 2 years and 7 months, CT showed very small low-density areas, which completely disappeared by April, 1998. The patient has had a good quality of life. According to the General Rules for Gastric Cancer Study, the patient belongs to the class of complete response.


Subject(s)
Adenocarcinoma/drug therapy , Adenocarcinoma/secondary , Antimetabolites, Antineoplastic/administration & dosage , Liver Neoplasms/secondary , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology , Tegafur/administration & dosage , Humans , Male , Middle Aged , Remission Induction , Suppositories
12.
Artif Organs ; 23(10): 932-8, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10564292

ABSTRACT

The undulation pump total artificial heart (UPTAH) was developed by using small-size continuous-flow displacement-type blood pumps (undulation pump). To clarify and improve the problems accompanied by the implantation in the chest, 14 animal experiments were performed on goats weighing 41.3-79.2 kg. The UPTAH could be implanted in the chest of all goats and was driven with a modulation pulsatile mode. The first problem was the atrial suction effect. This problem could be prevented to some extent by developing the soft disk and by improving atrial cuffs. An automatic detection and releasing of the atrial suction effect was also tried. The next problem was acute lung edema accompanied by the postural change of the animal. Development of the automatic control of left atrial pressure could prevent this problem. Small blood leakage from a pinpoint hole in the seal membrane was the next problem. Improvement of the manufacturing procedure of the membrane prevented this. With these improvements, a 10 day survival could be obtained with this unique implantable total artificial heart.


Subject(s)
Heart, Artificial , Acute Disease , Anastomosis, Surgical , Animals , Atrial Function, Right , Blood Pressure , Female , Goats , Heart Atria , Heart, Artificial/classification , Materials Testing , Membranes, Artificial , Posture , Prosthesis Design , Prosthesis Failure , Prosthesis Implantation , Pulmonary Edema/etiology , Pulmonary Edema/prevention & control , Pulsatile Flow , Surface Properties , Survival Rate
13.
Urol Res ; 27(5): 336-45, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10550521

ABSTRACT

We investigated whether testicular telomerase activity is due to telomerase expression in all cells or expression in a limited number of cells. Telomerase activity was assayed in highly purified fractions of spermatogonia cells plus primary spermatocytes, secondary spermatocytes plus round spermatids, secondary spermatocytes plus spermatids plus spermatozoa, round spermatids, or spermatozoa prepared from healthy or cryptorchid animals. Telomerase activity was additionally assayed in testicular tissue of prepubertal animals and animals with Sertoli cell only pathophysiology. Telomerase activity was detected in fractions containing primary spermatocytes and/or secondary spermatocytes and/or spermatids. Fractions enriched in round spermatids were positive for telomerase activity. In contrast, spermatozoa or Sertoli cell fractions were negative for telomerase activity. Using the relative telomerase activity assay and the sensitive quantitative telomerase assay to quantify telomerase activity, we showed that induction of cryptorchidism does not result in quantitative alterations in testicular tissue telomerase activity. In addition, elimination of round spermatids does not lead to significant alterations in testicular tissue telomerase activity. The present results suggest that the male gamete telomerase activity is inhibited during spermiogenesis. Furthermore, it appears that spermatogonia/primary spermatocytes are the main sources of telomerase activity in the testis.


Subject(s)
Spermatogenesis/physiology , Telomerase/antagonists & inhibitors , Testis/cytology , Testis/enzymology , Animals , Cryptorchidism/enzymology , Male , Meiosis/physiology , Mice , Mice, Inbred Strains , Sertoli Cells/enzymology , Spermatids/enzymology , Spermatocytes/enzymology , Spermatogonia/enzymology , Spermatozoa/enzymology , Telomerase/metabolism , Testis/physiology , Tissue Distribution
14.
Artif Organs ; 23(3): 221-8, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10198712

ABSTRACT

At the University of Tokyo, various types of total artificial heart (TAH) systems have been studied since 1959. At the present time, 2 types of implantable TAH have been developed. One is an undulation pump TAH (UPTAH) and the other is a flow transformed pulsatile TAH (FTPTAH). Using the UPTAH, 14 cases of implantation were performed in goats and 10 days' survival obtained. The new type of FTPTAH is under a prototype study. To prevent ring thrombus, a polyurethane membrane valve, a jellyfish valve, has been developed. The longest in vivo experiences with this valve in the TAH blood pump have been 312 days in the left side blood pump and 414 days in the right side blood pump. Conductance and arterial pressure based control (1/R control) can realize the physiological control of the TAH. Using 1/R control, 532 days of survival could be obtained in a goat with a paracorporeal TAH. The technique required to apply this control method to a implantable TAH is under development. We have proposed a new 5 year research project of the implantable TAH entitled "Comprehensive Basic Research on the Development of a Japanese Original Implantable Total Artificial Heart" to The Ministry of Welfare.


Subject(s)
Heart, Artificial , Animals , Female , Goats , Hemodynamics , Prosthesis Design , Pulsatile Flow , Tokyo
16.
J Virol ; 73(3): 2193-200, 1999 Mar.
Article in English | MEDLINE | ID: mdl-9971802

ABSTRACT

The La autoantigen (also known as SS-B), a cellular RNA binding protein, may shuttle between the nucleus and cytoplasm, but it is mainly located in the nucleus. La protein is redistributed to the cytoplasm after poliovirus infection. An in vitro translation study demonstrated that La protein stimulated the internal initiation of poliovirus translation. In the present study, a part of the La protein was shown to be cleaved in poliovirus-infected HeLa cells, and this cleavage appeared to be mediated by poliovirus-specific protease 3C (3Cpro). Truncated La protein (dl-La) was produced in vitro from recombinant La protein by cleavage with purified 3Cpro at only one Gln358-Gly359 peptide bond in the 408-amino-acid (aa) sequence of La protein. The dl-La expressed in L cells was detected in the cytoplasm. However, green fluorescence protein linked to the C-terminal 50-aa sequence of La protein was localized in the nucleus, suggesting that this C-terminal region contributes to the steady-state nuclear localization of the intact La protein in uninfected cells. The dl-La retained the enhancing activity of translation initiation driven by poliovirus RNA in rabbit reticulocyte lysates. These results suggest that La protein is cleaved by 3Cpro in the course of poliovirus infection and that the dl-La is redistributed to the cytoplasm. dl-La, as well as La protein, may play a role in stimulating the internal initiation of poliovirus translation in the cytoplasm.


Subject(s)
Autoantigens/metabolism , Cysteine Endopeptidases/physiology , Ribonucleoproteins/metabolism , Viral Proteins , 3C Viral Proteases , Animals , Cytoplasm/metabolism , HeLa Cells , Humans , Mice , Molecular Weight , Protein Biosynthesis , Rabbits , SS-B Antigen
17.
J Appl Physiol (1985) ; 84(3): 868-76, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9480945

ABSTRACT

To obtain a physiological response by a total artificial heart (TAH), while eliminating the hemodynamic abnormalities commonly observed with its use, we proposed the use of a conductance- and arterial pressure-based method (1/R control) to determine TAH cardiac output. In this study, we endeavored to make use of a variable more closely tied to central nervous system (CNS) efferents, systemic conductance, to provide the CNS with more direct control over the output of the TAH. The control equation that calculates the target cardiac output of the TAH was constructed on the basis of measurement of blood pressures and TAH flow. The 1/R control method was tested in TAH-recipient goats with an automatic method by using a microcomputer. In 1/R control animals, the typical TAH pathologies, such as mild arterial hypertension and substantial systemic venous hypertension, did not occur. Cardiac output varied according to daily activity level and exercise in a manner similar to that observed in natural heart goats. These results indicate that we have determined a control method for the TAH that avoids hemodynamic abnormalities exhibited by other TAH control systems and that exhibits physiological responses to exercise and daily activities under the conditions tested. The stability of the control and the complete lack of inappropriate excursions in cardiac output is suggestive of CNS involvement in stabilizing the system.


Subject(s)
Blood Pressure/physiology , Heart, Artificial , Neural Conduction/physiology , Animals , Autonomic Nervous System/physiology , Cardiac Output/physiology , Female , Goats , Hemodynamics/physiology , Neuronal Plasticity/physiology , Perfusion , Stroke Volume/physiology , Vascular Resistance/physiology
18.
Jpn J Thorac Cardiovasc Surg ; 46(11): 1182-5, 1998 Nov.
Article in Japanese | MEDLINE | ID: mdl-9884574

ABSTRACT

We experienced a case of spontaneous rupture of the esophagus after gastrointestinal examination using barium. A 48-year-old male experienced severe chest pain after vomiting following gastrointestinal examination. Chest X-ray revealed a right pneumothorax and pleural effusion by barium. We diagnosed spontaneous rupture of the esophagus and performed right thoracotomy 6 hours after onset of symptoms. At 10 cm above the diaphragm, there was a vertical perforation 3 cm in length. Following saline lavage, the ruptured esophageal wall was directly closed by the layer to layer method. The post operative course was uneventful and the patient was discharged 3 weeks after surgery. Cases of spontaneous rupture of the esophagus into the right thoracic cavity induced by gastrointestinal examination are extremely rare.


Subject(s)
Barium Sulfate/adverse effects , Contrast Media/adverse effects , Digestive System/diagnostic imaging , Esophageal Diseases/surgery , Esophageal Diseases/etiology , Humans , Male , Middle Aged , Radiography , Rupture, Spontaneous , Suture Techniques , Treatment Outcome
19.
Artif Organs ; 21(7): 665-9, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9212936

ABSTRACT

The undulation pump is a small size continuous flow displacement type blood pump that has been developed for an artificial heart. Using undulation pumps, 2 types of implantable total artificial hearts (TAHs), the undulation pump TAH (UPTAH) type 1 (UPTAH 1) and UPTAH type 2 (UPTAH 2) were developed. Both UPTAHs were designed to be small enough to implant into the chest of a goat, the experimental animal. UPTAH 1 could be reduced in size to 75 mm in diameter and 78 mm in length. The weight was 520 g. UPTAH 2 could be reduced in size to 75 mm in diameter and 80 mm in length. The weight was 650 g. UPTAH 2 could be tested in an animal experiment using an adult female goat weighing 52.3 kg. The UPTAH 2 could be implanted successfully into the goat's chest with a good fit. The goat stood after the surgery and extubation and survived for 3 h and 40 min; thus, the potential of the UPTAH for a practical implantable TAH was demonstrated.


Subject(s)
Heart, Artificial/trends , Animals , Biomechanical Phenomena , Blood Flow Velocity/physiology , Blood Pressure/physiology , Cardiac Output/physiology , Durable Medical Equipment , Equipment Safety , Female , Goats , Miniaturization , Polyurethanes/standards , Pulmonary Circulation/physiology , Pulmonary Wedge Pressure/physiology , Quality Control , Thrombosis/prevention & control
20.
Int J Artif Organs ; 20(1): 37-42, 1997 Jan.
Article in English | MEDLINE | ID: mdl-9062830

ABSTRACT

An electrochemical sensor system to allow real-time measurement and feedback of catecholamine concentrations was developed for use in the control of artificial hearts. Electrochemical analyses were carried out using a carbon fiber working electrode, an Ag-AgCl reference electrode, and a potentiostat. The operating parameters of the pneumatically-driven artificial heart system were altered in accordance with the algorithm for changes in the catecholamine concentration. The minimum detectable concentrations of both adrenaline and noradrenaline in a mock circulatory system using a phosphate-buffered solution were approximately 1-2 ng/ml (10(-8) mol/L). An artificial heart control system utilizing this set-up performed satisfactorily without delay, although sensor sensitivity decreased when placed in goat plasma instead of a phosphate-buffered solution, due to the adsorption of various substances such as plasma proteins onto the electrodes. This study demonstrated the future feasibility of a feedback control system for artificial hearts using catecholamine concentrations.


Subject(s)
Epinephrine/blood , Heart, Artificial/standards , Norepinephrine/blood , Adsorption , Algorithms , Animals , Blood Proteins/metabolism , Buffers , Carbon , Electrochemistry , Electrodes , Goats , Phosphates/chemistry , Reference Standards , Silver , Silver Compounds/chemistry
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