High-affinity alpha-aminobutyric acid A/benzodiazepine ligands: synthesis and structure-activity relationship studies of a new series of tetracyclic imidazoquinoxalines

A series of tetracyclic imidazoquinoxaline analogs was developed which constrain the carbonyl group of the partial agonist 3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-5-[(dimethylamino)carbonyl] - 4,5-dihydroimidazo[1,5-alpha]quinoxaline (2, U-91571) away from the benzene ring. These analogs orient the carbonyl group in the opposite direction of the previously reported full agonist 1-(5- cyclopropyl-1,2,4-oxadiazol-3-yl)-12,12a-dihydroimidazo[1,5- alpha]pyrrolo [2,1-c]quinoxalin-10(11H)-one (3, U-89267). A number of approaches were utilized to form the "bottom" ring of this tetracyclic ring system including intramolecular cyclizations promoted by Lewis acids or base, as well as metal-carbenoid conditions. The size and substitution pattern of the additional ring was widely varied. Analogs within this series had high affinity for the benzodiazepine receptor on the alpha-aminobutyric acid A chloride ion channel complex. From TBPS shift and Cl- current assays, the in vitro efficacy of compounds within this class ranged from antagonists to partial agonists with only 18a identified as a full agonist. Additionally, several analogs were quite potent at antagonizing metrazole-induced seizures indicating possible anticonvulsant or anxiolytic activity. Unlike 3, analogs in this series did not have high affinity for the diazepam insensitive alpha 6 beta 2 delta 2 subtype. These results suggest that either constraining the carbonyl group away from the benzene ring or the greater planarity that results from the additional cyclic structure provides analogs with partial agonist properties and prevents effective interaction with the alpha 6 beta 2 delta 2 subtype.     

Shared epitopes for HLA-A3-restricted melanoma-reactive human CTL include a naturally processed epitope from Pmel-17/gp100

Human CD8+ CTL recognize peptides bound to class I MHC molecules on the surface of melanoma cells. Several peptides derived from melanocyte lineage-specific proteins have been identified as epitopes for HLA-A2 restricted melanoma-reactive CTL. Because less than half of melanoma patients express HLA-A2, it is important to identify CTL epitopes restricted by other common MHC molecules including HLA-A1 and -A3. We have generated HLA-A3-restricted human CTL that recognize one or more shared melanoma Ags. All of the melanomas recognized by one of these CTL lines express Pmel-17/gp100, and those that fail to express this Ag are not lysed. This CTL line also specifically recognizes the lymphoblastoid line C1R-A3 following infection with a recombinant vaccinia encoding the melanocyte lineage-specific protein Pmel-17/gp100. Thus, at least one Pmel-17/ gp100 peptide is an epitope for this CTL line. We have identified ALLAVGATK (Pmel-17/gp100 residues 17-25) as an epitope for this CTL line and have shown that it is naturally processed and presented by HLA-A3 on melanoma cells. A second HLA-A3-restricted melanoma-reactive CTL line recognizes at least one additional shared epitope. These findings suggest that cellular immune responses directed against multiple shared melanoma epitopes exist in the 20 to 25% of melanoma patients who express HLA-A3. In addition, immunotherapy directed against Pmel-17/gp100 and other shared melanoma Ags may be useful in a large subset of these patients.     

An 85-kb tandem triplication in the slow Wallerian degeneration (Wlds) mouse

Wallerian degeneration is the degeneration of the distal stump of an injured axon. It normally occurs over a time course of around 24 hr but it is delayed in the slow Wallerian degeneration mutant mouse (C57BL/Wlds) for up to 3 weeks. The gene, which protects from rapid Wallerian degeneration, Wld, previously has been mapped to distal chromosome 4. This paper reports the fine genetic mapping of the Wld locus, the generation of a 1.4-Mb bacterial artificial chromosome and P1 artificial chromosome contig, and the identification of an 85-kb tandem triplication mapping within the candidate region. The mutation is unique to C57BL/Wlds among 36 strains tested and therefore is a strong candidate for the mutation that leads to delayed Wallerian degeneration. There are very few reports of tandem triplications in a vertebrate and no evidence for a mutation mechanism so this unusual mutation was characterized in more detail. Sequence analysis of the boundaries of the repeat unit revealed a minisatellite array at the distal boundary and a matching 8-bp sequence at the proximal boundary. This finding suggests that recombination between short homologous sequences ("illegitimate" or "nonhomologous" recombination) was involved in the rearrangement. In addition, a duplication allele was identified in two Wlds mice, indicating some instability in the repeat copy number and suggesting that the triplication arose from a duplication by unequal crossing over.     

The illusion of transparency: biased assessments of others' ability to read one's emotional states

Three sets of studies provide evidence for an illusion of transparency, or a tendency for people to overestimate the extent to which others can discern their internal states. People often mistakenly believe that their internal states "leak out" more than they really do. The authors attribute this bias to a tendency for people to adjust insufficiently from the "anchor" of their own phenomenological experience when attempting to take another's perspective. Evidence for this illusion is provided by showing that liars overestimate the detectability of their lies (Studies 1a, 1b, and 1c) and that people believe their feelings of disgust are more apparent than they actually are (Studies 2a and 2b). A final pair of experiments (Studies 3a and 3b) explores the implications of the illusion of transparency for people's reluctance to intervene in emergencies. All 3 sets of studies also provide evidence consistent with the proposed anchoring and adjustment interpretation.     

mTORC1 Inhibition via Rapamycin Promotes Triacylglycerol Lipolysis and Release of Free Fatty Acids in 3T3-L1 Adipocytes

Signaling by mTOR complex 1 (mTORC1) promotes anabolic cellular processes in response to growth factors, nutrients, and hormonal cues. Numerous clinical trials employing the mTORC1 inhibitor rapamycin (aka sirolimus) to immuno-suppress patients following organ transplantation have documented the development of hypertriglyceridemia and elevated serum free fatty acids (FFA). We therefore investigated the cellular role of mTORC1 in control of triacylglycerol (TAG) metabolism using cultured murine 3T3-L1 adipocytes. We found that treatment of adipocytes with rapamycin reduced insulin-stimulated TAG storage ~50%. To determine whether rapamycin reduces TAG storage by upregulating lipolytic rate, we treated adipocytes in the absence and presence of rapamycin and isoproterenol, a β2-adrenergic agonist that activates the cAMP/protein kinase A (PKA) pathway to promote lipolysis. We found that rapamycin augmented isoproterenol-induced lipolysis without altering cAMP levels. Rapamycin enhanced the isoproterenol-stimulated phosphorylation of hormone sensitive lipase (HSL) on Ser-563 (a PKA site), but had no effect on the phosphorylation of HSL S565 (an AMPK site). Additionally, rapamycin did not affect the isoproterenol-mediated phosphorylation of perilipin, a protein that coats the lipid droplet to initiate lipolysis upon phosphorylation by PKA. These data demonstrate that inhibition of mTORC1 signaling synergizes with the β-adrenergic-cAMP/PKA pathway to augment phosphorylation of HSL to promote hormone-induced lipolysis. Moreover, they reveal a novel metabolic function for mTORC1; mTORC1 signaling suppresses lipolysis, thus augmenting TAG storage.     

Endothelium-medicated control of the coronary circulation. Exercise training-induced vascular adaptations

This review discusses the role of the endothelium in the regulation of coronary vascular function. The role of endothelium-mediated mechanisms at rest, during exercise, in exercise training-induced adaptations of coronary function and in the presence of coronary heart disease (CHD) are examined. Mechanisms of control of coronary blood flow are briefly discussed with emphasis on endothelium-mediated control of vascular resistance. The concept that the relative importance of vascular control mechanisms differs as a function of position along the coronary arterial tree is developed and discussed. Metabolic, myogenic and endothelium-mediated control systems contribute in parallel to regulating coronary blood flow. The relative importance of these mechanisms varies throughout the coronary arterial tree. Endothelium-dependent vasodilation contributes to maintenance of resting coronary blood flow but the endothelium's role in dilation of small resistance arteries, thereby increasing coronary blood flow during exercise, remains in question. In contrast, the endothelium plays an essential role in dilation of the conduit coronary arteries during exercise. Atherosclerosis and CHD convert this exercise-induced dilation to a vasoconstriction, apparently due to endothelium dysfunction. Long term increases in physical activity and exercise training alter the control of coronary blood flow. Adaptations in endothelium-mediated control play a role in these changes. However, the effects of the mode, frequency, and intensity of exercise training bouts and duration of training on adaptive changes in endothelial function have not been established. The role of the endothelium in control of the permeability characteristics of the exchange vessels in the coronary circulation is discussed. Current evidence indicates that vascular permeability is a dynamic characteristic of the vessel wall that is controlled, at least in part, by endothelium-dependent phenomena. Also, preliminary results indicate that exercise training alters microvessel permeability and the control of permeability in the coronary circulation. Further research is needed to provide clarification of the effects of exercise training on coronary endothelial control of vascular resistance and vascular permeability in atherosclerosis and CHD.     

Sigma-binding site ligands inhibit K+ currents in rat locus coeruleus neurons in vitro

The effect of triphenyltin on the activity of membrane-bound pyrophosphatase of Rhodospirillum rubrum was investigated. Triphenyltin inhibits the hydrolysis of chromatophore membrane-bound pyrophosphatase in a pH-dependent pattern, being maximal at pH 9-10. At basic pH values, the inhibition produced by this organotin on membrane-bound pyrophosphatase is very similar to that produced on the chromatophore H+ATPase (I50 = 14.4 and 10 microM, respectively). Detergent-solubilized membrane-bound pyrophosphatase is also inhibited by triphenyltin, but the cytoplasmic enzyme of R. rubrum is inhibited only slightly. The inhibitory effect of triphenyltin on membrane-bound pyrophosphatase is the same with Mg-PPi or Zn-PPi, and is dependent on the chromatophore membrane concentration. Triphenyltin modified mainly the Vmax of the enzyme, and only slightly its Km. Free Mg2+ does not reverse the inhibition. Reducing agents prevent triphenyltin inhibition of the membrane-bound pyrophosphatase, but their effect is due to an alteration of the inhibitor, and not to a modification of thiol groups of the enzyme. The most likely site for triphenyltin inhibition in chromatophore membrane-bound pyrophosphatase is a component either within or closely associated with the membrane.     

Basis for the calculation of personnel requirements: the nursing personnel regulation

The paper presents the data on morphofunctional changes in some rabbit organs (the liver, kidney, intestine, lung, heart) invaded with the nematode Passalurus ambiguus. The most profound inflammatory and dystrophic changes were found in the cecum which was a site of helminths. The signs of vacuolar dystrophy were also observed in the hepatic and renal parenchyma. There was activation of the immune system and mobilization of overall compensatory responses of the animals.