Effect of LaF3: Ag fluorescent nanoparticles on photodynamic efficiency and cytotoxicity of Protoporphyrin IX photosensitizer.

LaF3: Ag nanoparticles (NPs) were synthesized by the co-precipitation method. The produced NPs were characterized by X-ray diffraction (XRD) pattern, scanning electron microscope (SEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The emission spectrum of LaF3:Ag NPs is mostly overlapped with the absorption band of protoporphyrin IX (PpIX) and their conjugation was confirmed by studying fluorescence resonance energy transfer (FRET) from LaF3:Ag donor to protoporphyrin IX acceptor. The energy transfers from LaF3:Ag NPs to photosensitizer molecules is very efficient. So, the produced LaF3:Ag NPs can be recommended as light source for photodynamic therapy (PDT). The thiol group of cysteine was bound to LaF3:Ag NPs in order to conjugate LaF3:Ag NPs and protoporphyrin IX. UVC light source was used to excite fluorescent LaF3:Ag NPs. The reactive oxygen species (ROS) produced by photosensitizer was identified using special fluorescent probes (anthracene, methylene blue and methyl orange) as detectors.

Effect of transfusion on cerebral oxygenation, flow velocity in a patient with sickle cell anemia and Moyamoya disease: a case report.

Vascular occlusive diseases affect brain blood flow, brain metabolism and are associated with arterial ischemic stroke. This study was designed to measure the brain blood flow velocity, brain oxygenation, hemoglobin concentrations, hematocrit, and cell free hemoglobin at pre- and post-exchange red cell transfusion in an 18 year old male patient with sickle cell disease and moyamoya syndrome (MMS). Exchange transfusion increased cerebral oxygen saturation 12%, total hemoglobin concentration 2%, hemoglobin AA 80%, and reduced sickle (SS) hemoglobin 12%, arterializations 33%, and cell free hemoglobin 33%. Brain blood flow velocity values were unaffected by transfusion. These observations suggest that exchange transfusion increases the hemoglobin carrying capacity and reduces sickle hemoglobin and shunting of blood, which may improve the peripheral and cerebral oxygenation. Transfusion did not affect the brain blood flow in this patient. Therefore the risk of transient ischemic attack and arterial ischemic stroke from mms still exist.

Cerebral oximetry in patients with sickle cell disease.

BACKGROUND: There is limited information concerning the brain's oxygen supply and demand in patients with sickle cell disease. DESIGN: We measured near-infrared spectroscopy of brain oxygenation in 27 patients with sickle cell disease regardless of vaso-occlusive crisis, 14 normal healthy controls, and five anaemic patients without sickle cell disease. We also measured pre- and post-transfusion cerebral oximetry in 14 additional sickle cell disease patients who were on transfusion programmes. RESULTS: The mean cerebral oxygen saturation in the combined steady-state and vaso-occlusive crisis population was found to be significantly lower than that in the controls and in anaemic patients without sickle cell disease (47.7% vs. 61.3%, 59.8%, P < 0.0001). Cerebral oxygen saturation failed to correlate with the haemoglobin concentration (r = 0.51, P > 0.5). However, cerebral oxygen saturation increased from 40.4% to 49.6% (P = 0.01) and correlated significantly with the haemoglobin level (r = 0.553, P = 0.003) in 14 subjects studied before and after transfusions. In seven subjects who received simple transfusions, cerebral oxygen saturation correlated strongly and positively with the haemoglobin level (r = 0.811, P = 0.001) and with percent normal haemoglobin (r = 0.786, P = 0.002), and negatively with abnormal sickle haemoglobin (r = -0.775, P = 0.003). None of these correlations was found to be statistically significant in the seven subjects given exchange transfusions. Cerebral oxygen saturation measured in the sickle cell disease subjects after transfusions was still significantly lower than in the anaemic subjects without sickle cell disease and in the normal controls (49.6% vs. 59.8% and 61.3%, P = 0.001). CONCLUSIONS: We found that patients with sickle cell disease have subnormal values of cerebral oxygen saturation. Red cell transfusions significantly increased the brain oxygenation in these patients. Cerebral oximetry may be a useful, noninvasive method for assessing the effect of circulating normal red cells in sickle cell patients after transfusions.