Solid and papillary epithelial neoplasms of the pancreas: CT findings

Five female patients and one male patient with solid and papillary epithelial neoplasms of the pancreas were examined with computed tomography (CT). The mean age of the patients was 27 years (range, 13-46 years). All cases showed well-encapsulated, round or lobulated masses consisting of both cystic and solid areas. Cystic portions showed CT numbers that suggested hemorrhagic necrosis. There were no internal septations within the masses. In three tumors located in the head of the pancreas, dilatation of the biliary tree was absent or minimal, although the masses were large. Two tumors contained calcifications. One tumor demonstrated metastatic deposits in liver and lymph nodes. Metastatic masses appeared similar to the primary pancreatic mass. Solid and papillary neoplasm of the pancreas should be the primary diagnostic consideration when characteristic CT findings are detected in a young female patient.     

Advanced primary breast cancer: assessment at mammography of response to induction chemotherapy

The response to induction chemotherapy is an important prognostic factor in patients with nonmetastatic, locally advanced breast carcinomas. Assessment at mammography of the response of 60 breast cancers in 59 women was performed between 1974 and 1986. Responses were excellent in 13 tumors, moderate in 34, and poor in 13 (excellent moderate = 78%). Assessment of response of discrete masses in a fatty breast was easiest; assessment of response of tumor areas that were poorly defined-such as a focal area of architectural distortion or mass in dense breast parenchyma-was more difficult. Of 17 patients with excellent pathologic responses-that is, minimal or no residual tumor-15 (88%) had complete responses (no residual tumor) as determined with mammography, physical examination, or both. Mammography provides information complementary to physical examination and is essential in the accurate assessment of the response to chemotherapy of locally advanced breast cancer.     

Invited review: Neuroprotective properties of certain beta-adrenoceptor antagonists used for the treatment of glaucoma.

Although it is known that ganglion cell death causes loss of vision in glaucoma, the pathogenesis of the disease is complex, probably involving an initial ischemic insult to the ganglion cell axons and glial cells with the ganglion cell bodies eventually being affected. It may therefore be necessary to blunt many stages in the pathogenesis of the disease to obtain a clinically effective neuroprotective strategy. In animal experiments, one cause of ganglion cell death in ischemia is an overactivation of glutamate receptors and a subsequent rise in intracellular levels of sodium and calcium ions as well as a generation of reactive oxygen species. In contrast, optic nerve death in ischemia is mainly caused by an influx of sodium and reversal of the sodium/calcium exchanger, which leads to a rise in intracellular calcium. Thus, a substance that reduces the influx of sodium will protect the ganglion cell axon, and if it also reduces calcium influx and/or acts as an antioxidant it will protect the ganglion cell body in addition. Of all antiglaucoma drugs, only beta-blockers have both calcium and sodium channel blocking activity, with betaxolol being the most efficacious of those analyzed. In addition, of the tested ophthalmic beta-blockers only metipranolol has powerful antioxidant properties. Moreover, laboratory studies on rats have shown that topically applied beta-blockers attenuate ischemic injury to ganglion cells by mechanisms that do not appear to involve an action on beta-receptors. Thus, of the substances used to lower intraocular pressure in glaucoma, beta-blockers have unique additional characteristics that also give them the capacity to act as neuroprotectants.     

GGA1 acts as a spatial switch altering amyloid precursor protein trafficking and processing

The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD.     

Laying the Cytotaxonomic Foundations of a New Model Grass, Brachypodium distachyon (L.) Beauv.

Brachypodium distachyon is a ubiquitous, temperate grass species which is being developed and exploited as an alternative model to rice, in order to gain access to important syntenic regions of the genomes of less tractable relatives such as wheat. As part of this initiative, this paper describes for the first time the cytotaxonomy of members of the polyploid series of this species, and challenges the assumption that the series evolved simply by chromosome doubling. In situ hybridization using genomic DNA probes and rDNA markers uncovers a hybrid origin of several of the polyploid ecotypes, and sheds light upon the complex evolution of this species and its close relatives.