Magnetic resonance imaging features of pituitary yttrium-90 rod implantation

Intersellar implantation of yttrium-90 rods was a common treatment for a variety of pituitary tumours in the 1960s and 1970s. The magnetic resonance (MR) imaging features in three patients with implants (two for growth hormone-secreting and one for prolactin-secreting pituitary adenomas) are presented: the implants appeared as low signal cylinders with no image distortion, in contradistinction to CT where the implants generate beam hardening and back projection artefacts. Confident evaluation of the pituitary fossa for residential tumour and sequelae of therapy could be made on MR. It is the imaging technique of choice in the follow-up of patients treated with yttrium-90 implants.     

Temperature-sensitive Gbeta mutants discriminate between G protein-dependent and -independent signaling mediated by serpentine receptors

Deletion of the single gene for the Dictyostelium G protein beta-subunit blocks development at an early stage. We have now isolated temperature-sensitive alleles of Gbeta to investigate its role in later development. We show that Gbeta is directly required for adenylyl cyclase A activation and for morphogenetic signaling during the entire developmental program. Gbeta was also essential for induction of aggregative gene expression by cAMP pulses, a process that is mediated by serpentine cAMP receptors (cARs). However, Gbeta was not required for cAR-mediated induction of prespore genes and repression of stalk genes, and neither was Gbeta needed for induction of prestalk genes by the differentiation inducing factor (DIF). cAMP induction of prespore genes and repression of stalk genes is mediated by the protein kinase GSK-3. GSK-3 also determines cell-type specification in insects and vertebrates and is regulated by the wingless/wnt morphogens that are detected by serpentine fz receptors. The G protein-dependent and -independent modes of cAR-mediated signaling reported here may also exist for the wingless/wnt signaling pathways in higher organisms.     

Risk factors for drug-related problems in elderly ambulatory patients

Medication use among elderly patients in ambulatory care, home health care, and long-term care settings has become increasingly complicated during the past decade. Home intravenous therapy, multiple drug regimens to treat multiple chronic diseases, increased acuity of nonhospitalized patients, and increased longevity have placed elderly patients at increased risk for drug-related problems.     

Random mutagenesis of the cAMP chemoattractant receptor, cAR1, of Dictyostelium. Evidence for multiple states of activation

cAMP receptor 1 (cAR1) of Dictyostelium couples to the G protein G2 to mediate activation of adenylyl and guanylyl cyclases, chemotaxis, and cell aggregation. Other cAR1-dependent events, including receptor phosphorylation and influx of extracellular Ca2+, do not require G proteins. To further characterize signal transduction through cAR1, we performed random mutagenesis of the third intracellular loop (24 amino acids), since the corresponding region of other seven helix receptors has been implicated in the coupling to G proteins. Mutant receptors were expressed in car1(-) cells and were characterized for G protein-dependent and -independent signal transduction. Our results demonstrate that cAR1 is remarkably tolerant to amino acid substitutions in the third intracellular loop. Of the 21 positions where amino acid substitutions were observed, one or more replacements were found that retained full biological function. However, certain alterations resulted in receptors with reduced ability to bind cAMP and/or transduce signals. There were specific signal transduction mutants that could undergo cAMP-dependent cAR1 phosphorylation but were impaired either in coupling to G proteins, in G protein-independent Ca2+ influx, or in both pathways. In addition, there were general activation mutants that failed to restore aggregation to car1(-) cells and displayed severe defects in all signal transduction events, including the most robust response, cAMP-dependent cAR1 phosphorylation. Certain of these mutant phenotypes were obtained in a complementary study, where the entire region of cAR1 from the third to the seventh transmembrane helices was randomly mutagenized. Considered together, these studies indicate that the activation cycle of cAR1 may involve a number of distinct receptor intermediates. A model of G protein-dependent and -independent signal transduction through cAR1 is discussed.     

Prognostic value of bacteriological studies in peritonitis

Based on multiple bacteriological assays of lymph and blood, it is concluded that single detection of pathogenic microorganisms in lymph and blood should not be considered an unfavourable prognostic sign. A provisional external drainage of the thoracic duct would reduce intoxication in patients with peritonitis, and it is estimated as a valuable prophylactic method of combating against bacteriemia.     

Myelination in cerebellar slice cultures: development of a system amenable to biochemical analysis

Myelin deposition and maintenance are critical to proper function of the mammalian nervous system. Previous investigations of myelination in the central nervous system (CNS) were hampered by the lack of an in vitro system that can faithfully reproduce in vivo events yet is amenable to biochemical investigation. We have developed a procedure, based on organotypic cultures, which permits efficient preparation of large numbers of cerebellar slice cultures that can be easily manipulated. Cultures have been examined to document myelination biochemically (by incorporation of [35S]sulfate into sulfolipids), immunohistochemically (by labeling the myelin components myelin basic protein and galactocerebroside), and morphologically (by both light and electron microscopy). We tested the effects of biologically active peptides and antibodies on myelination in the thin slices. The results indicate that the cultures provide an in vitro system that can be used to examine specific cellular events that occur during CNS myelination.     

Nuclear data sheets for A = 104

Nuclear structure data available through January 1976 are compiled, and adopted level properties are given. The bulk of the data is presented pictorially for easy comparison. Experimental details, references, and additional comments, where required, are given in the text. All drawings, tables, and comments are reproduced from the computerized Evaluated Nuclear Structure Data File (ENSDF). Any additions or corrections desired by the users should be addressed to the compilers for maintenance and updating of the computer file.     

A novel frequency-multiplication device based on three-terminalballistic junction

In this letter, a novel frequency-multiplication device based on a three-terminal ballistic junction is proposed and demonstrated. A 100 nm-size, three-terminal ballistic junction and a one-dimensional (1D), lateral-field-effect transistor with trench gate-channel insulation are fabricated from high-electron-mobility GaInAs/InP quantum-well material as a single device. The devices show frequency doubling and gain at room temperature. The performance of these devices up to room temperature originates from the nature of the device functionality and the fact that the three-terminal device extensions are maintained below the carrier mean-free path. Furthermore, it is expected that the device performance can be extended up to THz-range