The mechanisms of particulate pollution-related cardiovascular morbidity and mortality are not well understood. We studied the passage of radioactively labeled ultrafine particles after their intratracheal instillation. Hamsters received a single intratracheal instillation of 100 microg albumin nanocolloid particles (nominal diameter < or = 80 nm) labeled with 100 microCi technetium-99m and were killed after 5, 15, 30, and 60 min. In blood, radioactivity, expressed as percentage of total body radioactivity per gram blood, amounted to 2.88 +/- 0.80%, 1.30 +/- 0.17%, 1.52 +/- 0.46%, and 0.21 +/- 0.06% at 5, 15, 30, and 60 min, respectively. Thin-layer chromatography showed only one peak of radioactivity corresponding to unaltered (99m)Tc-albumin nanocolloid. In the liver, radioactivity, expressed as percentage of total radioactivity per organ, amounted to 0.10 +/- 0.07%, 0.23 +/- 0.06%, 1.24 +/- 0.27%, and 0.06 +/- 0.02% at 5, 15, 30, and 60 min, respectively. Lower values were observed in the heart, spleen, kidneys, and brain. Dose dependence was assessed at 30 min following instillation of 10 microg and 1 microg (99m)Tc-albumin per animal (n = 3 at each dose), and values of the same relative magnitudes as after instillation of 100 microg were obtained. We conclude that a significant fraction of (99m)Tc-albumin, taken as a model of ultrafine particles, rapidly diffuses from the lungs into the systemic circulation.

This dual-targeting approach may be a simple and workable solution for cancer treatment and deserves further exploitation.

1. The regions of the human brain responsive to motion were mapped using the H2(15)O position emission tomography (PET) activation technique and compared by viewing a moving random dot pattern with a stationary dot pattern. The stimulus was optimized in dot density and 3 degrees in diameter. 2. In addition to bilateral foci at the border between Brodmann areas 19 and 37, a V1/V2 focus and a focus in the cuneus reported earlier, we observed activations in other visual areas (lower BA 19 and the parieto-occipital fissure) in the cerebellum and in two other, presumed vestibular areas, the posterior bank of lateral sulcus and at the border of BA 2/40. 3. Homologies between monkey and human cortex are discussed.

No abstract

Post-mortem measures of Abeta amyloid deposition correlate only weakly with cognitive dysfunction antemortem. We tested the hypothesis that functional reorganization forms a critical intermediary step between Abeta amyloid-associated brain injury and clinical disease expression. Fifteen patients with early-stage probable Alzheimer's disease (AD) and 16 cognitively intact controls participated in this combined functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) study. The fMRI design had two factors: task (associative-semantic versus visuoperceptual judgement) and input-modality (written words versus pictures). We measured Abeta amyloid by means of Pittsburgh Compound B (11C-PIB). In the posterior third of the left superior temporal sulcus (STS), the fMRI response during the associative-semantic compared with the visuoperceptual task was lower in AD than in controls, in particular for words. Response amplitude correlated inversely with PIB uptake in this region. Contralaterally, the functional pattern differed substantially: the fMRI response in the right posterior STS during the associative-semantic versus the visuoperceptual task was higher in AD than in controls. Accuracy on the Boston Naming test correlated positively with the degree to which AD patients were able to recruit the right STS (r = 0.84, P(corrected) = 0.014). PIB uptake did not correlate with naming accuracy. Functional reorganization of the language system in response to Abeta amyloid-related brain injury exists in early-stage AD and determines the degree of anomia more than Abeta amyloid load per se does.

The results suggest that hypericin derivatives may serve as powerful necrosis-avid diagnostic agents for assessment of tissue viability.

The study indicates the suitability of [(123)I]MIH for in vivo visualization of myocardial infarcts.

No abstract