Positron emission tomography of pituitary macroadenomas: hormone production and effects of therapies.

Positron emission tomography with [18F]fluorodeoxyglucose (FDG) was carried out in 24 patients with pituitary macroadenomas (32 studies) to assess the glucose utilization of these tumors in vivo. The adenoma metabolic index, which is the ratio of FDG uptake of tumor to a whole brain slice, was calculated. Comparisons were made between tumor uptake of FDG and hormone secretion and response to therapies.

Pituitary microadenomas: a PET study.

Twenty cases of surgically verified pituitary microadenoma (17 with Cushing disease and three with acromegaly) were studied with positron emission tomography (PET) with use of fluorine-18-2-fluorodeoxyglucose (FDG). The diagnostic results were compared with those of other modalities, namely, computed tomography (CT), magnetic resonance (MR) imaging, and, in the cases of Cushing disease, simultaneous bilateral inferior petrosal sinus sampling (SIPS). The PET results showed 12 positive readings and one questionable reading, compared with seven positive readings and one questionable reading for CT (18 cases studied) and 13 positive and two questionable MR imaging readings.

Toward the engineering of photosynthetic productivity.

This article is a review of progress towards a general quantitative theory of photosynthetic productivity or autotrophy in plants. It is not intended to be an exhaustive review, but rather a perspective of the autotrophic puzzle and current approaches to its solution. The review describes attempts to quantitatively describe a generalized plant based on theoretical expressions for its component parts.

Concentration-dependent Unloading as a Necessary Assumption for a Closed Form Mathematical Model of Osmotically Driven Pressure Flow in Phloem.

Previous attempts to model steady state Münch pressure flow in phloem (Christy and Ferrier. [1973]. Plant Physiol.