RESUMEN
Hybrid complexes of fluorescent nanoparticles and tetrapyrrole dyes are currently considered as promising third-generation photosensitizers for photodynamic therapy, including cancer treatment. Using nanoparticles as a platform for delivery of photosensitizers to target cells can increase the efficiency of photodynamic action. In this work, we synthesized a complex of polymer-coated CdSe/ZnS quantum dots, substituted phthalocyanines and human transferrin. Such complexes effectively enter human epidermoid carcinoma cells (A431) due to transferrin-mediated endocytosis and are localized in the perinuclear compartment. We observed an efficient excitation energy transfer from the quantum dot to phthalocyanine in the cells, which indicates stability of the complex upon its internalization. It was shown that the photodynamic activity of hybrid complexes covalently bonded to transferrin is 15% higher than the activity of unmodified hybrid complexes. Our results confirm the feasibility of using fluorescent nanoparticles to enhance the photodynamic properties of photosensitizers based on tetrapyrrole dyes.
Asunto(s)
Indoles/química , Fotoquimioterapia , Puntos Cuánticos/química , Transferrina/metabolismo , Línea Celular Tumoral , Transferencia de Energía , Estudios de Factibilidad , Humanos , Indoles/uso terapéutico , Isoindoles , Fenómenos Ópticos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Simultaneous measurements by the Fick direct method and the Kubicek rheographic method of cardiac output of 20 men with ischemic heart disease have shown that both methods are well correlated (r = 0.76, k = 0.92, n = 41). The reproducibility of the Kubicek data was slightly better than the Fick data (on the average +/- 6% instead of +/- 9-10%). An attempt of increasing the correlation of the Kubicek data with the Fick data by correcting the specific resistance with respect to the hematocrit data and the chest perimeter failed. In order to provide the necessary accuracy of the Kubicek method, it is required that the procedure be stringent and the five variables in the formula for calculating cardiac output be precisely measured. The cardiac output values determined simultaneously by the Kubicek method and by x-ray contrast ventriculography showed a better correlation (r = 0.88, k = 0.97, n = 15).
Asunto(s)
Gasto Cardíaco , Cardiografía de Impedancia/métodos , Monitoreo Fisiológico/métodos , Pletismografía de Impedancia/métodos , Adulto , Enfermedad Coronaria/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Volumen SistólicoAsunto(s)
Pletismografía de Impedancia/métodos , Animales , Conductividad Eléctrica , Electrodos , Humanos , Modelos Biológicos , ConejosRESUMEN
The study of 54 healthy male test subjects demonstrated significantly different responses of motion sickness susceptible and resistant people to 10-minute occlusion of their femoral veins. The changes in limb rheograms, as well as heart rate and stroke volume indicated that in motion sickness susceptible subjects the circulating blood volume in the upper body decreased, whereas in motion sickness resistant subjects it remained unaltered or increased in response to the occlusion.
Asunto(s)
Volumen Sanguíneo , Mareo por Movimiento/fisiopatología , Vena Femoral/fisiología , Trajes Gravitatorios , Hemodinámica , Humanos , Pletismografía de Impedancia , Factores de TiempoRESUMEN
Vascular responses of fingers and toes to the occlusion test as well as fingers, head, lungs and liver to the Valsalva maneuver were studied. The responses to the tests depended on the initial level of blood filling. The different level of blood filling was induced by orthostatic, head-down tilt and LBNP tests. It is recommended to use rheography (slow and pulse components) in combination with the occlusion test and Valsalva maneuver in order to assess regional blood filling and venous tone of crew-members in space flights.
Asunto(s)
Circulación Sanguínea , Adulto , Femenino , Enfermedades de las Válvulas Cardíacas/fisiopatología , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Válvula Mitral , Pletismografía de Impedancia , Postura , Flujo Sanguíneo Regional , Vuelo Espacial , Vacio , Maniobra de Valsalva , Venas/fisiologíaRESUMEN
Central and peripheral circulation was studied rheographically in 6 test subjects during a 30-day bed rest experiment and in 9 test subjects during a 49-day bed rest. The bed rested subjects were kept in a head-down position at an angle of --4 degrees. At an early stage of the experiments the cardiac output and stroke volume increased, the total peripheral resistance decreased, the tone of major regional vessels decreased and that of small vessels increased. During the 3rd-7th weeks the changes were just the opposite: cardiac output and stroke volume decreased, the total peripheral resistance increased the tone of major regional vessels increased and that of small vessels decreased. At the end of the bed rest experiment the cardiac output and stroke volume increased and the tone of regional vessels changed accordingly. Circulation parameters returned to the pretest level, at least, 3-4 weeks after the end of the best rest experiments.