Evaluation of allograft perfusion by radionuclide first-pass study in renal failure following renal transplantation.

To assess the diagnostic value of indices measured on a first-pass curve, we performed 72 radionuclide renal first-pass studies (RFP) in 21 patients during the early weeks following renal allograft transplantation. The diagnosis was based on standard clinical and biochemical data and on fine needle aspiration biopsy (FNAB) of the transplant. Aortic and renal first-pass curves were filtered using a true low-pass filter and five different indices of renal perfusion were computed, using formulae from the literature.

Mössbauer spectroscopy study of iron overloaded livers.

Absorption 57Fe Mössbauer spectra have been carried out directly on fresh or lyophylized tissues of liver with either normal iron depot or iron overload. Two types of overloading have been studied: primary iron overload due to an excessive intestinal iron absorption and secondary iron overload (hemosiderosis) produced in beta-thalassemia patients by hypertransfusional therapeutics. The Mössbauer spectra, at room temperature, 77 and 4.

Dopaminergic receptor sites in human brain: positron emission tomography.

Positron emission tomography (PET) and 11C-labeled pimozide were used to study the dopaminergic (DA) receptor sites in the human striatum by comparing the latter with the cerebellum, which lacks DA receptors. Although 11C-pimozide concentration was not different in these two brain structures up to 53 minutes after IV injection (thus implying large nonspecific binding), a significant retention of radioactivity in striatum relative to cerebellum was found in controls but not in subjects pretreated with the unlabeled competitor haloperidol. This suggests that the striatal retention seen in controls was due to specific binding of 11C-pimozide to DA receptor sites, whereas prior occupation of the receptor sites by the unlabeled competitor was achieved in pretreated subjects.

X-irradiation effect on human red cells: hemoglobin study by Mössbauer spectrometry.

This work is a study of the radioinduced transformations undergone by intraglobular hemoglobin. Mössbauer spectrometry allows us to study in a wide range of doses the effect of X rays on deoxyhemoglobin as well as on oxyhemoglobin. Using this technique we have shown large differences between these two derivatives of hemoglobin.

[Water diffusion and measurement of cerebral blood flow by C15O2 inhalation].

Measurement of local Cerebral Blood Flow (CBF) using the C15O2 continuous inhalation technique coupled with Position Emission Tomography (PET) rests on the assumption that the in vivo labelled water (H215O) of blood diffuses freely within the brain water pool. This requirement however, may be disputed: in the rhesus monkey, Eichling et al (1974) showed a linear relationship between the single-pass extraction of water (E) and CBF after intra-carotid H215O injection, such that E decreases as CBF increases. Such a limitation in water transport across the blood brain barrier has also been suggested to exist in man (Paulson, 1977).