64 results about "Isolated heart" patented technology

A process for pre-processing recorded and digitised heart sounds and corresponding digitised ECG signals is provided. The pre-processed signals (203) are suitable for input into an automatic decision support system implemented by means of a diagnostic decision network (205), used for diagnosing and differentiation between normal / functional (206) and pathological (207) heart murmurs, particularly in paediatric patients. The process includes identifying or predicting locations of individual heart beats within the heart sound signal, identifying the positions of the S1 and S2 heart pulses within the respective heart beats, predicting and identifying the locations and durations of the systole and diastole segments of the heart beats (302), determining if segmentation of the heart sound signal is possible based on the selected and isolated heart beats (305), and the segmentation of the respective heart beats into segments for allowing better feature extraction. The invention also provides a process for detecting the QRS complex of an ECG signal for optimizing the number of heart beat cycles detected.

An isolated heart or heart-lung preparation in which essentially normal pumping activity of all four chambers of the heart is preserved, allowing for the use of the preparation in conjunction with investigations of electrode leads, catheters, ablation methods, cardiac implants and other medical devices intended to be used in or on a beating heart. The system can be designed to be used within a Magnetic Resonance Imaging (MRI) unit or a X-ray computed tomography (CT) scanner. The preparation may also be employed to investigate heart and lung functions, in the presence or absence of such medical devices. In order to allow comparative imaging visualizations of either or simultaneously the heart and / or lung structures and devices located within the chambers of the heart or vessels or bronchi within the lungs, a clear perfusate such as a modified Krebs buffer solution with oxygenation is circulated through all four chambers of the heart and thus the coronary and / or pulmonary vasculatures. A ventilator with intubation tube can be used to inflate / deflate the lungs and / or provide oxygen to the isolated organs. The preparation and recordings of the preparation may be used in conjunction with the design, development and evaluation of devices for use in or on the heart and / or lungs, as well as for use as an investigational and teaching aid to assist physicians and students in understanding the operation of the cardiopulmonary system.

The invention relates to an amphibian isolated heart perfusion device. The device comprises an arterial cannula, a venous cannula, a drip recording electrode and an electrocardio lead electrode, wherein the arterial cannula is formed by combining an arterial cannula trunk, an aorta inserting end and a liquid discharging pipe through a three-way valve; the venous cannula is formed by combining a liquid storage tank, a postcaval vein inserting end and a liquid adding pipe through a three-way valve, and parts of the arterial cannula and the venous cannula are inserted and combined into one. The drip recording electrode comprises a drip recording electrode head, a drip recording electrode rod and a signal input end; the electrocardio lead electrode comprises an electrocardio lead electrode head, an electrocardio lead electrode rod, a signal input end, a heart outer wall liquid adding pipe and a three-way valve. The multifunctional amphibian isolated heart perfusion device is suitable for one person to operate, facilitates perfusion liquid replacement, and is suitable for synchronously and dynamically detecting dynamical changes of the cardiac output, myocardial contraction tension, electrocardiogram and various cardiac function indexes.

The invention provides a high-purity cardiac muscle cell primary culture method and is suitable for the field of biotechnology and medical science. The high-purity cardiac muscle cell primary culture method particularly comprises the steps that an isolated heart of a suckling mouse is sheared into tissue fragments; digestion is conducted on the tissue fragments through improved prepared enzyme digestive juice for multiple times, cardiac muscle cell suspension is prepared, resuspension is conducted, and then cardiac muscle cells are inoculated in a culture dish A for differential-time wall sticking; cardiac muscle cell suspension in the culture dish A is sucked into a culture dish B, cardiac muscle cells which sink to the bottom of the culture dish A and do not stick to the wall in the culture dish A are cleaned and resuspended, and then the resuspended cardiac muscle cells are transferred into the culture dish B to be cultured. Compared with the prior art, the high-purity cardiac muscle cell primary culture method has the advantages that the method is simple and effective, the operability is strong, the number of obtained cardiac muscle cells is large, the purity is high, the wall sticking rate is good, and the survival rate is high.

The invention discloses a rapid hanging and fixing device for an isolated perfused heart. The rapid hanging and fixing device comprises a support, a perfusion needle adjustment device arranged on the support, and a hanging device used for fixing the external isolated heart. The hanging device is arranged on the support. A perfusion needle fixing frame is arranged on the adjustment device. The perfusion needle fixing frame can be controlled by the adjustment device to move so that a perfusion needle arranged on the perfusion needle fixing frame can be accurately inserted in an appropriate position in an aorta of the isolated heart and temporarily fixed, and then the aorta is fixed to the perfusion needle through silk thread ligation. In the whole operation process, it can be effectively avoided that because misoperation is generated by shaking of human hands, aortic valves are damaged and the heart is not firmly fixed or fixed at poor positions, and the rapid hanging and fixing device has the advantages that operation is convenient, the perfusion needle can be conveniently and accurately inserted in the aorta of the heart and then fixed through knotting, and the perfused heart can be transferred as a whole.

The present invention relates to a real-time biosignal measurement apparatus for cardiac ischemia and reperfusion. The apparatus includes: a peristaltic pump which pumps perfusate from a tank storing the perfusate; a pressure trap which offsets the pulsation of both sides between a solution chamber temporarily storing the pumped perfusate and the perfusate tank; a heat exchanger to which the temporarily stored perfusate is applied and which transfers the heat of the perfusate; a bubble trap to which the heat transferred perfusate is applied on one side and which filters the heat transferred perfusate to transduce the perfusate to an isolated heart connected to the other side; a sensor unit which detects the gas concentration value in the myocardium of the isolated heart in real time during the cardiac ischemia reperfusion; and a control unit which is supplied with the gas concentration value in the myocardium of the isolated heart in order to analyze its correlation with the degree of a myocardial injury of the isolated heart.

The invention discloses an in-vitro myocardial perfusion device which comprises a base and a support. A water bath cylinder is fixed to the top of the support, a K-H liquid bottle and a mixed gas bottle are arranged in the water bath cylinder, charging ports are formed in the top of the K-H liquid bottle and the top of the mixed gas bottle, the bottom of the K-H liquid bottle and the bottom of themixed gas bottle are connected with a spiral mixer through organic glass tubes, the spiral mixer is connected with a peristaltic pump through a glass tube, the bottom of the peristaltic pump is connected with a perfusion liquid cannula, an oblique tube is connected to the glass tube between the peristaltic pump and the perfusion liquid cannula and is connected with a 20 ml injector, a stop screwis arranged on the 20 ml injector, a 20 G liquid dropping head is arranged at the bottom of the perfusion liquid cannula, a perfusion utensil is arranged at the bottom of the 20 G liquid dropping headand is connected with a 100 ml injector through a rubber hose, the 100 ml injector is installed at the left end of the support, and a transducer is arranged on the left side of the base and is connected with the rubber hose through a glass tube.

The invention relates to an extraction method and application of icariside I in Korean epimedium herb leaves. The extraction method not only can avoid low yield caused by the irreversible adsorption of a chromatographic column, but also can extract a large amount of high-purity icariside I. In the extraction method, content measurement is carried out by a high efficiency liquid chromatography, the quality extraction rate of the icariside I is more than 60 percent, the quality is easy to control, and the method is simple and rapid. In the invention, the research in the aspect of pharmacology is carried out on the icariside I and proves that the icariside I has a protective action for pituitrin-induced rat myocardial ischemia and is concretely shown as the action of inhabiting T waves and the action of inhabiting J point displacement change. The icariside I has the protective action for guinea-pig isolated hearts and is concretely shown as the action of increasing the coronary blood flow of guinea pigs. The icariside I obtained through the invention is used in preparing a medicament for treating heart diseases.

The invention relates to a high-purity polyphyllin VI preparation method and an application, and belongs to the field of Chinese herbal medicine extraction and separation. The method includes the specific steps: roughly crushing Chinese paris rhizome or wake robin medicinal materials, performing ethanol extraction; sequentially performing macroporous adsorption resin, silica gel and reverse-phase material column chromatography on extracting solution; taking ethyl acetate, ethanol and water as eluting agents and filtering, washing and drying sedimentation portions after recovering solvents by eluent to obtain high-purity polyphyllin VI. The method has the advantages that the operation steps are easily repeated, conditions are easily controlled and amplified, the solvents are low in toxicity and easy to recover, and the like. The obtained polyphyllin VI is basically free from organic solvent residues, and the purity of the polyphyllin VI reaches 98% or more. After pharmacodynamical research of the influence of mouse normal pressure hypoxia tolerance, mouse brain ischemia caused by common carotid artery ligation, rat myocardium injury caused by ischemia reperfusion, myocardial infarction caused by rat isolated heart myocardial ischemia and the like, the polyphyllin VI serving as a final product is good in effect and can be used for developing products for treating cardiovascular and cerebrovascular diseases.

The invention discloses a constant-temperature incubator for an isolated perfused heart. The constant-temperature incubator for an isolated perfused heart comprises an incubator body and a mobile device, wherein a test tank and a heating tank are formed in the incubator body; the test tank is connected with the heating tank, is subjected to heat exchange with the heating tank through a heat conductor, and is communicated with an external liquid inlet pipe; a drain pipe is arranged at the bottom of the test tank; and the mobile device is located above the incubator body and is used for driving an external liquid inlet pipe to move forward and backward and up and down. According to the constant-temperature incubator, the isolated heart is put into the test tank; heat exchange is carried out between the test tank and the heating tank through the heat conductor so that a constant physiological temperature environment is provided for incubation of the isolated heart; the mobile device is used for driving the external liquid inlet pipe to synchronously move forward and backward and up and down together with the perfused isolated heart so as to ensure that the isolated heart can be adjusted to a proper position; the isolated heart is stably fixed through a transparent element and a heart fixing device; implementation of a photographing or electrocardiosignal recording and stimulating procedure is facilitated; and incubation of the isolated heart and detection of related tests are facilitated.

The invention discloses an isolated heart transfer box. A heart fixing shell is connected inside a limiting shell; the limiting shell is detachably connected inside a temperature regulating shell; theheart fixing shell is in the shape of a heart external structure; the heart fixing shell is of a screen-shaped structure; the limiting shell is of a screen-shaped structure; and a temperature regulating pipeline is arranged inside the temperature regulating shell, so that the temperature regulating pipeline controls the temperature of a medium inside the temperature regulating shell. The isolatedheart transfer box solves the problem that an isolated heart easily moves inside the transfer box and then is damaged as the positioning fixing effect for the isolated heart is not strong in an isolated heart transfer process in the prior art. According to the isolated heart transfer box disclosed by the invention, the isolated heart is fixed by the heart fixing shell, and the isolated heart is buffered and protected through the heart fixing shell, the limiting shell and a connecting structure between the heart fixing shell and the limiting shell as well as a connecting structure between thelimiting shell and the temperature regulating shell, so that the isolated heart is prevented from being damaged, and therefore, the isolated heart is completely protected, and life characteristics ofthe isolated heart are guaranteed to not damage.

The invention discloses a nifedipine medicine composition and a preparation method thereof. The nifedipine medicine composition contains nifedipine, hydroxymethyl propyl cellulose and microcrystalline cellulose. The hydroxymethyl propyl cellulose is used as slow-releasing framework material; the weight ratio of the nifedipine and the hydroxymethyl propyl cellulose is 2:1-1:1; and the weight ratio of the nifedipine and the microcrystalline cellulose is 1:4-1:3; and lactose, starch, calcium hydrophosphate and glucose can be also added. The method for preparing the nifedipine medicine composition comprises the following steps of: (1) crushing and screening; (2) drying; and (3) tabletting. According to the invention, the dissolution rate of the nifedipine in the water can be increased, the coronary arteries in the normal blood supply area and the ischemic area are relaxed while the absorption rate of the nifedipine in the body is increased so that coronarospasm and is released and prevented and myocardial contraction is inhibited; myocardial oxygen consumption is reduced; the peripheral resistance is released; after load of heart is reduced; sinus node function and atrioventricular conduction of the isolated heart are slowed down; and the nifedipine medicine composition is applicable to variant angina pectoris, unstable angina pectoris and chronic stable angina pectoris.

The invention relates to a normal-temperature in-vitro heart transfer device which comprises a protective shell, a first cover and a base, universal wheels are arranged at the bottom of the base, a temperature adjusting pipeline is arranged on the inner wall of the protective shell, a partition plate is arranged in the protective shell, and a heart storage device is arranged above the partition plate. The heart storage device is fixedly connected with the partition plate through a fixing rod. A peristaltic pump, a heart perfusate storage device, a temperature changer, a membrane oxygenator anda heart perfusate filter are arranged on the upper part of the base, and the heart storage device, the heart perfusate filter, the peristaltic pump, the heart perfusate storage device, the temperature changer and the membrane oxygenator are sequentially communicated through a perfusate conveying pipe. The cardiac perfusate filter is positioned on the bottom end surface of the partition plate; a buzzer, an operation panel and a control box are arranged on the front end face of the protective shell, and a second cover is arranged on the lower portion of the front end face of the protective shell.

The invention discloses an oxygen carrier based on a hemoglobin-haptoglobin compound and a preparation method of the oxygen carrier. The oxygen carrier comprises haptoglobin, hemoglobin, antioxidant and pyridoxal phosphate. The hemoglobin-haptoglobin compound is formed as a unit for bringing the oxygen carrying activity into play by virtue of special combination ability of the haptoglobin and the hemoglobin. The oxygen carrier based on the hemoglobin-haptoglobin compound disclosed by the invention is free of hypertension reaction after being infused, and capable of protecting an isolated heart. And therefore, the oxygen carrier can be used for clinical blood transfusion, protecting vital organs including the heart and the like from ischemia reperfusion injuries, and has good application prospects and economical benefits.

The invention discloses application of atractylodin in the preparation of drugs for treating and preventing heart failure, and belongs to the field of medicine. Atractylodin can significantly increase maximum rising speed of left ventricular developed pressure and left ventricular pressure of rat isolated heart, is dependent on concentration, causes no significant effect on heart rate, and is free of adverse effect causing arrhythmia. It is indicated that atractylodin has positive inotropic action and is not dependent on neurohumor. Atractylodin can significantly increase a normal rat's end-systolic volume, end-systolic pressure, stroke volume, ejection fraction, cardiac output, left ventricular pressure maximum rising speed, stroke work, and slope of end-systolic pressure-volume relational curve. It is indicated that atractylodin has positive inotropic action without increasing heart rate.

The invention discloses an in-vitro heart valve testing system and a testing method thereof, the testing system comprises a simulated heart, a circulating device and a monitoring device, the simulatedheart has a complete heart structure, a circulating path and a puncture port for simulating release of the heart valve, and the simulated heart is an animal isolated heart; the circulating device comprises power equipment and liquid storage equipment, and the power equipment is connected with a left ventricular apex part or / and a right ventricular apex part of the simulated heart and used for providing power for the simulated heart; the liquid storage equipment is used for providing circulating liquid for the test system; the circulating device is connected with the simulated heart to form aleft heart circulating system and / or a right heart circulating system, the left heart circulating system is used for testing a mitral valve and / or an aortic valve, and the right heart circulating system is used for testing a tricuspid valve and / or a pulmonary valve; the monitoring device comprises a pressure monitoring device, and the pressure monitoring device is used for detecting pressure changes before and after the interventional valve is released. The system provided by the invention has universality and a wide application range.

The invention relates to a detection method for isolated perfusion heart active oxygen and mitochondrial membrane potential, which comprises the following steps of: establishing an isolated perfusion heart ischemia reperfusion model; realizing correlation of an isolated heart perfusion system, a probe loading device and a laser scanning confocal microscope; further carrying out real-time loading and microscope imaging on a fluorescence probe of the active oxygen and mitochondrial membrane potential; and finally, through image processing and data analysis, the method can be used for real-time and positioning measurement of heart ROS (reactive oxygen species) and mitochondrial membrane potential in various isolated heart models taking acute overload, ischemia reperfusion and the like as representatives under a stable perfusion state. The detection method has the characteristics of directness, accuracy, visibility, time and space positioning, and synchronized measurement of beating cardiac metabolism and function, and has the advantages of low cost, high efficiency, and good reliability and repeatability.

The invention discloses a method for optical imaging of a living myocardial sheet, and belongs to the technical field of optical imaging. The method for optical imaging of a living myocardial sheet comprises the following steps of step 1: perfusion of an isolated heart; step 2: loading of a calcium-sensitive fluorescent dye and a voltage-sensitive fluorescent dye; step 3: preparation of a living short-axis myocardial sheet; and step 4: optical mapping. The method combines optogenetic technique, optical mapping and living myocardial sheet technology, performs the short-axis sectioning of the heart of a photogenetical transgenic mouse, and adopts an ultra-high-rate camera for optical mapping for detecting and analyzing the conduction characteristics of myocardial membrane potential and calcium transients after blue light stimulation, thereby opening up a new research method for the physiology and pathology of the heart.

The invention relates to a hemolysis-free continuous isolated heart transfer device which comprises a box body and a box cover, a circulating liquid cavity and a heart placing cover are arranged in the box body, the heart placing cover is of a solid net-shaped structure similar to the shape of the heart, two blood vessel penetrating-out connectors are arranged on the heart placing cover, a displacement pump circulating device is arranged in the circulating liquid cavity, a liquid inlet pipe and a liquid outlet pipe are connected to the displacement pump circulating device, the liquid inlet pipe and the liquid outlet pipe are aligned to the two blood vessel penetrating-out connectors respectively, and elastic ribbons are arranged on the blood vessel penetrating-out connectors. In the heart transfer process, the heart can be kept in a circulating state, meanwhile, blood cell damage is effectively reduced, damage to the heart caused by in-vitro transfer is reduced, and the heart transplantation success rate is increased.

The invention discloses a lactim compound possessing cardiotonic action, its preparation method and its purpose. The lactim compound shown in a formula I is obtained from an ethyl acetate extract of edible fungi Tricholoma Matsutake Sing, and is identified as 3,5dimethyl-1-nitrogen bicycle [5,2,1] decane-2,10-dione. The mammal experiments show that the compound possesses the cardiotonic action with different degrees can obviously improve the heart function of cardiac failure animals and inhibit the cardiac vicarious hypertrophy. The effect for obviously increasing the myocardial contractilityis provided in in-vitro heart, no influence on the heart rate is generated, and the basic oxygen consumption of the heat is not increased. The integral animal experiments show that the lactim compound can treat acute or chronic heart failure induced by operation and chemical medicaments, and possesses obvious improvement effects on change of the heart function and pathology caused by heart failure.

The invention discloses coix seed small fried dough twists and a making method thereof. According to the coix seed small fried dough twists disclosed by the invention, coix seed powder is used as a preparation raw material of the small fried dough twists, the coix seed powder also contains special functional components of coixol, coixenolide, coix seed polysaccharide, triterpene compounds, flavonoid compounds and the like besides general nutrient substances of protein, fat, minerals, vitamins and the like, and early-stage pharmacology research indicates that the coix seeds have the efficacy ofresolving heat, tranquilizing the mind, alleviating pain and the like, and have exciting effects on isolated heart, intestines and uteruses. Modern pharmacology research indicates that functional components of the coix seeds have pharmacological activity of resisting tumors, enhancing immunity, reducing blood sugar, reducing blood calcium, reducing blood pressure, resisting viruses, restraining trypsin, inducing ovulation and the like. The small fried dough twists made from the coix seed powder can effectively increase the general nutrient components of the protein, minerals, the vitamins andthe like, as well as the functional components of the coixenolide, the coix seed polysaccharide and the like, the fried dough twists are balanced in nutrition, the effects of preserving the health and being health care can be achieved, and the fried dough twists have unique flavor and mouth feel, and are excellent in palatability.

The invention belongs to the field of animal experiment modeling methods, and relates to a polypeptide for constructing a long QT syndrome animal model and a method for establishing an animal model for an animal experiment. According to the polypeptide for constructing the long QT syndrome animal model, an amino acid sequence of the polypeptide is GRKKRRQRRRGEVDEMIREADIDGDGQVNYEGFVQMM, and the polypeptide is named as CM4. The method for establishing the long QT syndrome animal model comprises the step of administering the polypeptide CM4 to an animal to obtain the long QT syndrome animal model. The model establishing method provided by the invention is simple and reliable, and is convenient for researchers to establish a long QT syndrome mouse or guinea pig isolated heart model and carry out related experimental researches. The modeling process is simple and effective, meanwhile, a corresponding control group can be set, and electrocardiogram changes before and after amino acid mutation are compared and analyzed. The CM4 is given to induce the QT interval of isolated hearts of mice and guinea pigs to be prolonged, the CM4 is easy to obtain and high in purity, the CM4 can penetratethrough cell membranes to enter cells to play a role, the activity of myocardial calcium channels is adjusted, the molding efficiency is high, the cost is low, and research of related experiments is facilitated.

The invention discloses an isolated heart perfusion experiment device. The isolated heart perfusion experiment device comprises a heart perfusion device with a perfusion catheter and a remaining needle. The remaining needle comprises a puncture needle and a catheter of which two ends are opened. The rear end of the catheter is fixedly provided with a fixing connector which is used for detachably connecting the liquid outlet end of the perfusion catheter. The fixing connector is provided with a port communicated with a cavity of the catheter. The front end of the puncture needle successively passes through the port and the cavity of the catheter. The isolated heart perfusion experiment device is used, so that a heart taken from a laboratory mice body can be conveniently and rapidly suspended on a heart perfusion device by an operator, and the activity of the taken heart is guaranteed. The invention further discloses an isolated heart perfusion experiment method using the isolated heartperfusion experiment device.

The invention relates to a detection method for isolated perfusion heart active oxygen and mitochondrial membrane potential, which comprises the following steps of: establishing an isolated perfusion heart ischemia reperfusion model; realizing correlation of an isolated heart perfusion system, a probe loading device and a laser scanning confocal microscope; further carrying out real-time loading and microscope imaging on a fluorescence probe of the active oxygen and mitochondrial membrane potential; and finally, through image processing and data analysis, the method can be used for real-time and positioning measurement of heart ROS (reactive oxygen species) and mitochondrial membrane potential in various isolated heart models taking acute overload, ischemia reperfusion and the like as representatives under a stable perfusion state. The detection method has the characteristics of directness, accuracy, visibility, time and space positioning, and synchronized measurement of beating cardiac metabolism and function, and has the advantages of low cost, high efficiency, and good reliability and repeatability.

The invention discloses a single-phase action potential recording system including an attached electrode and a recording device. The attached electrode is in contact with an isolated heart and is connected with the recording device. The recording device utilizes the attached electrode to acquire and to record single-phase action potentials of the isolated heart. By adopting the scheme provided by the invention, accuracy and the like of recording results can be improved.

The invention discloses an incubator for an in-vitro heart experiment. The incubator comprises a box body, a top cover and a front cover, wherein the top cover is detachably connected to the top of the box body, and the front cover is detachably connected to the front side of the box body. The box body comprises side plates and a bottom plate, wherein inner cavities are formed in the side plates and the bottom plate correspondingly, the inner cavities in the side plates and the inner cavity in the bottom plate are communicated with each other to form an integrated closed heat preservation cavity, heat preservation liquid is arranged in the heat preservation cavity, and two liquid passing pipes communicated with the heat preservation cavity are arranged on the side plates and are served as an inlet and an outlet for heat-insulating liquid respectively. The heat preservation cavity is formed in the box body, the heat preservation liquid is uninterruptedly circulated in the heat preservation cavity, a constant-temperature environment is created in the box body, a perfusion device is matched to enable an isolated heart to be in a constant-temperature state all the time in the experiment process, and the accuracy of the experiment result is guaranteed.

The invention discloses an isolated heart transfer box. A heart fixing shell is connected inside a limiting shell; the limiting shell is detachably connected inside a temperature regulating shell; theheart fixing shell is in the shape of a heart external structure; the heart fixing shell is of a screen-shaped structure; the limiting shell is of a screen-shaped structure; and a temperature regulating pipeline is arranged inside the temperature regulating shell, so that the temperature regulating pipeline controls the temperature of a medium inside the temperature regulating shell. The isolatedheart transfer box solves the problem that an isolated heart easily moves inside the transfer box and then is damaged as the positioning fixing effect for the isolated heart is not strong in an isolated heart transfer process in the prior art. According to the isolated heart transfer box disclosed by the invention, the isolated heart is fixed by the heart fixing shell, and the isolated heart is buffered and protected through the heart fixing shell, the limiting shell and a connecting structure between the heart fixing shell and the limiting shell as well as a connecting structure between thelimiting shell and the temperature regulating shell, so that the isolated heart is prevented from being damaged, and therefore, the isolated heart is completely protected, and life characteristics ofthe isolated heart are guaranteed to not damage.

Systems and methods for performing perfusion and contractility assessments for a heart are provided. The system can operate in any of Langendorff mode, pump-supported working mode, passive working mode, and right-sided working mode. The system includes a reservoir from which one or more pumps are operable to supply a heart with fluids and collect fluids output therefrom. One or more clamps can beused to switch between Langendorff, pump-supported, passive, and right-sided working modes.