Efficacy of ultraviolet light-emitting diodes (UV-LED) at four different peak wavelengths against Cryptosporidium parvum oocysts by inactivation assay using immunodeficient mice.

As an alternative to using ultraviolet (UV) lamps, which are made with mercury that is toxic to the environment and human health, UV light-emitting diodes (UV-LEDs) are expected to be effective for inactivating microorganisms in water. Although UV-LEDs have been reported to be effective against bacteria and viruses, the effectiveness of UV-LEDs against Cryptosporidium parasites has not been fully evaluated. As we report here, we have developed an in vivo quantitative inactivation assay for C. parvum oocysts using immunodeficient mice. Using the assay, we evaluated the effectiveness of treatment by UV lamp (254 nm) at approximately 1000 µJ/cm2 (for 3 s at a distance of 95 mm) compared to inactivation by commercially available UV-LEDs (with peak wavelengths of 268, 275, 284, and 289 nm). The shed patterns of oocysts after treatment with 284- and 289-nm wavelength UV-LEDs were significantly delayed compared to that after treatment with a UV lamp. These findings provide the first suggestion that UV-LEDs are effective against these parasites, as assessed using commercially available 350-mA UV-LEDs under conditions of fixed exposure distance and time.

Shaggy aorta syndrome after acute arterial macroembolism: report of a case.

We report the case of a patient who underwent treatment for a macroembolism in the right lower leg, which led to shaggy aorta syndrome. Anticoagulant therapy for the macroembolism and intra-aortic catheterization exacerbated the patient's renal function and triggered another massive microembolization of the visceral arteries, with a fatal outcome. To minimize the incremental complications inherent to this syndrome, awareness and prompt diagnosis with enhanced computed tomography or intravenous digital subtraction aortography are essential. Axillo-bifemoral bypass with bilateral external iliac artery ligations, performed with optimal timing, could save patients with shaggy aorta syndrome.

Hemolysis in an electromechanical driven pulsatile total artificial heart.

A motor rotation in an electromechanically-driven pulsatile total artificial heart (TAH) may influence hemolysis. This study is designed to evaluate motor rotational conditions of the TAH and choose a suitable condition to obtain the least hemolytic characteristics. The TAH was driven in two motor rotational conditions: a constant motor rotational speed (rpm) mode (mode A) and a gradually increasing rpm mode (mode B). In these two modes, a maximum dP/dt value and a degree of hemolysis were measured and compared. The TAH was connected to an in vitro testing loop. In each mode, the TAH was driven with a fixed pumping rate of 100 bpm. A preload and an afterload were held at 15 and 100 mm Hg, respectively. The outflow of the TAH was maintained at 4.0 L/min. The maximum dP/dt in mode A and mode B was 5914 +/- 405 mm Hg/s and 2953 +/- 191 mm Hg/s, respectively. The NIH value obtained from mode A and mode B was 0.063 +/- 0.005 g/100 L and 0.026 +/- 0.003 g/100 L, respectively. The results demonstrated that the TAH driven in a gradually increasing rpm mode reduces both a maximum dP/dt value and a degree of hemolysis. The gradually increasing rpm mode is a suitable driving condition to obtain the least hemolytic characteristics.

Improvement on the auxiliary total artificial heart (ATAH) left chamber design.

The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH's beating frequency is regulated through the change of the left preload, based on Frank-Starling's law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25 degrees C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light. With left mean preload fixed at 10 mm Hg and the afterload at 100 mm Hg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color micro-camera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared.

Improvement on the auxiliary total artificial heart (ATAH). Left chamber design

The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH’s beating frequency is regulated through the change of the left preload, based on Frank- Starling’s law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25°C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light.With left mean preload fixed at 10mmHg and the afterload at 100mmHg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color microcamera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared. Key Words: Total artificial heart— Ventricle assist device—Cardiac output—Mock circulation system—Flow visualization...

Testes in vitro e in vivo com o Coração Artificial Auxiliar (CAA): um novo modelo de coração artificial totalmente implantável e heterotópico / In vitro and in vivo tests with the Auxiliary Total Artificial Heart (ATAH): a new device of a totally implantable and heterotopic artificial heart

Um novo modelo de coração artificial está sendo desenvolvido e testado em nossos laboratórios, o Coração Artificial Auxiliar (CAA). Este dispositivo foi projetado com dimensões reduzidas para ser implantado em paralelo ao coração natural do paciente, dentro da cavidade torácica direita de forma heterotópica. Foram realizados testes in vitro, em um circuito simulador do sistema circulatório humano, para verificação do desempenho hidrodinâmico do CAA. Os resultados mostraram que o CAA pode fornecer um fluxo de até 5,8 L/min, com uma pré-carga de 20 mmHg e uma pós-carga de 100 mmHg. A freqüência de batimento do CAA e, consequentemente, o débito cardíaco são dependentes da pré-carga do ventrículo esquerdo, funcionamento semelhante ao coração natural (Lei de Frank Starling). Testes in vivo animal estão sendo realizados para avaliar os resultados obtidos com os testes in vitro e para verificar o comportamento do CAA em ambiente e condições fisiológicas difíceis de serem simuladas. Os testes in vivo estão sendo também importantes para o desenvolvimento de técnicas cirúrgicas e treinamento dos cirurgiões cardiovasculares envolvidos no projeto. Até o momento, dois estudos agudos in vivo foram realizados, com o CAA funcionando por 5h, implantado na cavidade torácica direta de carneiros adultos (50 + ou - 5 kg). Os resultados destes estudos in vivo demonstraram que o funcionamento do CAA é sincronizado ao coração natural, sendo possível estudar o comportamento do CAA quando, gradativamente, o coração natural teve sua contratilidade reduzida até sua parada total.

Sequence and analysis of a 31 kb segment of the Bacillus subtilis chromosome in the area of the rrnH and rrnG operons.

A 31141 bp continuous nucleotide sequence in the region from trnl to pNEXT52 in the Bacillus subtilis 168 genome was determined. In the region, there were 22 ORFs, two complete rRNA operons, and five tRNA genes. It was deduced that the function of one of the ORFs was similar to that of a sigma factor belonging to the ECF (extra-cytoplasmic functions) subfamily. The gene cluster feuA, B, C reported previously for other strains of B. subtilis was also found in strain 168 and located in this region.

Characteristics of a Blood Pump Combining the Centrifugal and Axial Pumping Principles: The Spiral Pump.

Two well-known centrifugal and axial pumping principles are used simultaneously in a new blood pump design. Inside the pump housing is a spiral impeller, a conically shaped structure with threads on the surface. The worm gears provide an axial motion of the blood column through the threads of the central cone. The rotational motion of the conical shape generates the centrifugal pumping effect and improves the efficiency of the pump without increasing hemolysis. The hydrodynamic performance of the pump was examined with a 40% glycerin-water solution at several rotation speeds. The gap between the housing and the top of the thread is a very important factor: when the gap increases, the hydrodynamic performance decreases. To determine the optimum gap, several in vitro hemolysis tests were performed with different gaps using bovine blood in a closed circuit loop under two conditions. The first simulated condition was a left ventricular assist device (LVAD) with a flow rate of 5 L/min against a pressure head of 100 mm Hg, and the second was a cardiopulmonary bypass (CPB) simulation with a flow rate of 5 L/min against 350 mm Hg of pressure. The best hemolysis results were seen at a gap of 1.5 mm with the normalized index of hemolysis (NIH) of 0.0063 ± 0.0020 g/100 L and 0.0251 ± 0.0124 g/100 L (mean ± SD; n = 4) for LVAD and CPB conditions, respectively.

Visualizaçäo de fluxo em um coraçäo artificial eletro-mecânico comparando diferentes velocidades dp motor / Visualization of the flow in a electromechanical artificial heart comparative different speeds dp motor

Um coração artificial totalmente implantável (TAH) está sendo desenvolvido e testado em nossos laboratórios. Este TAH utiliza um motor de corrente contínua, sem escovas, e um atuador mecânico (parafuso de esferas) para movimentar dois diafragmas (direito e esquerdo). O presente estudo foi realizado para obtenção de informações sobre o comportamento do fluxo dentro da câmara esquerda, usando três diferentes velocidades do motor. Um circuito com tubos e reservatórios foi usado com água e glicerina (37 por cento) a 25 Graus Celssius, conectado ao coração artificial, para simular as condições de funcionamento do ventrículo esquerdo. Partículas (Amberlite, 80 mesh) foram iluminadas por um feixe plano e estroboscópico de luz laser hélio-neon. Os resultados mostram que, embora ocorram aumentos nas velocidades das particulas com a elevação da velocidade do motor, não existe nenhuma alteração desfavorável no comportamento do fluxo, nas áreas da saída e entrada da câmara esquerda do TAH.

Abstract: A total ai1ificial heai1 (TAH) has been developed and tested in our laboratory. lt uses a brushless DC motor and a mechanical actuator (roller screw) to move two diaphragms (left and right). The present study was conducted to obtain information about the flow behavior inside the left chamber, using three different motor speeds. A mock circuit was used with water and glycerin (37%) at 25ºC, simulating the left ventricle conditions. Plastic particles (Amberlite, 80 mesh) were illuminated by a stroboscopic planar helium-neon laser light. The results show that, although the particle velocities increase when the motor speed was increased. there is no unfavorable change in the flow behavior, in the outlet and inlet area of the T AH left chamber

Indices de hemodiálise e visualizaçäo do fluxo na "Spiral Pump" (SP), uma bomba centrífuga de sangue por fuso crônico / Hemodialysis indices and visualization of the flow in \"Spiral Pump\" (SP), a blood centrifugal pump for conic spindle

A "Spiral Pump" (SP) é uma bomba de sangue que utiliza, simultaneamente, os princípios de bombeamento axial e centrífugo, através da rotação de um fuso cônico. As características hidrodinâmicas da SP foram estudadas em diversas condições de bombeamento, utilizando um circuito composto de tubos e reservatório plásticos, com 500 ml de solução água-glicerina (37 por cento). O comportamento do fluxo foi estudado nas áreas mais importantes da bomba utilizando um plano de luz laser estroboscópica. Partículas plásticas, suspensas na solução, foram iluminadas pela luz laser durante o funcionamento da bomba. Vários testes de hemólise foram realizados "In Vitro" utilizando sangue bovino, simulando duas condições de bombeamento: bomba de assistência ventricular esquerda e bomba de circulação e oxigenação extracorpórea

Abstract: The Spiral Pump (SP) is a blood pump that utilizes the two well known centrifugai and axial pumping principies, simultaneously. The hydrodynamic performance of the pump was studied at severa! test conditions, using a closed circuit loop with plastic tubes and reservoir, filled with 500 mi of 37% glycerin-water solution. The results show that the SP has good pumping performance. The flow behavior was studied in the most important areas of the pump using a stroboscopic planar helium-neon laser light. Amberlite plastic particles (80 mesh) were used in suspension in the solution and were illuminated by the laser light during the pumping process. Severa! in vitro hemolysis tests were performed using bovine blood, simulating two pump conditions: as left ventricular assist device and as cardiopulmonary bypass