Disruption of cellular translational control by a viral truncated eukaryotic translation initiation factor 2alpha kinase homolog

Phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha) is a common cellular mechanism to limit protein synthesis in stress conditions. Baculovirus PK2, which resembles the C-terminal half of a protein kinase domain, was found to inhibit both human and yeast eIF2alpha kinases. Insect cells infected with wild-type, but not pk2-deleted, baculovirus exhibited reduced eIF2alpha phosphorylation and increased translational activity. The negative regulatory effect of human protein kinase RNA-regulated (PKR), an eIF2alpha kinase, on virus production was counteracted by PK2, indicating that baculoviruses have evolved a unique strategy for disrupting a host stress response. PK2 was found in complex with PKR and blocked kinase autophosphorylation in vivo, suggesting a mechanism of kinase inhibition mediated by interaction between truncated and intact kinase domains.     

Heparin removal after cardiopulmonary bypass in a patient with adverse reaction to protamine

A 74-year-old man underwent elective coronary surgery under cardiopulmonary bypass. A few minutes after the protamine administration was started, he suddenly developed a severe hypotension necessitating cardiac massage and recannulation for pump assistance. A further test dose of protamine provoked an identical reaction. We installed a Heparin Removal Device, which allows for ex-vivo deheparinization. In 35 minutes ACT decreased from 480 sec to 180 sec and clots appeared in the operating field. This system provides an excellent alternative to protamine in patients with an adverse reaction to protamine.     

Seasonal variations in T-lymphocyte response to grass pollen allergens from pollen-allergic patients and healthy controls

Recurrence of membranous nephropathy after renal transplantation has been reported either anecdotally or in a few series. In the present study, the potential risk factors as well as hitherto unreported actuarial risk for recurrence and graft loss due to recurrence were evaluated by combining data of a series of transplanted patients with MN at Louvain Medical School (n = 12) and at Lyon (n = 18; previously reported by Couchoud et al. 1995) giving a total of 30 patients. No risk factor for recurrence was identified as there was no statistical difference between the patients with and without recurrence for duration of MN in native kidneys or of pretransplant hemodialysis, presence of HLA-DR3, graft origin and use of cyclosporin. Actuarial risk for recurrence reached 29% at 3 years, plateauing up to 10 years. The outcome of recurrence was poor since the actual risk for graft loss among patients with recurrent MN was 38 and 52% at 5 and 10 years, respectively.     

Modeling the cross-sectional relationships between religion, physical health, social support, and depressive symptoms

The authors examined models of the relationships between religious activities, physical health, social support, and depressive symptoms in a sample of 4,000 persons age 65 and over. Religious activity was examined first as a single composite construct and then split into three component variables that were examined individually. Religious activity as a single construct was correlated with both social support and good physical health but was unrelated to depression. Split into the three components, model fit was significantly increased. Frequency of church attendance was positively related to physical health and negatively related to depression, but was surprisingly unrelated to social support. Frequent churchgoers were about half as likely to be depressed. Private prayer/Bible reading was negatively correlated with physical health and positively correlated with social support, but unrelated to depression. Religious TV/radio listening was unrelated to social support, negatively related to good physical health, and, unexpectedly, positively associated with depression.     

Identification of a firefly luciferase active site peptide using a benzophenone-based photooxidation reagent

Firefly luciferase catalyzes the highly efficient emission of yellow-green light from substrate luciferin by a series of reactions that require MgATP and molecular oxygen. We prepared 2-(4-benzoylphenyl)thiazole-4-carboxylic acid (BPTC), a novel benzophenone-based substrate analog, intending to use it in photoaffinity labeling studies to probe the luciferase active site. Instead, we found that while BPTC was a potent photoinactivating reagent for firefly luciferase, it was not a photoaffinity labeling agent. Using proteolysis, reverse phase high-performance liquid chromatography, tandem high performance liquid chromatography-electrospray ionization mass spectrometry, and Edman sequencing, we identified a single luciferase peptide, 244HHGF247, the degradation of which was directly correlated to luciferase photoinactivation. Results of enzyme kinetics and related studies were consistent with this peptide being at or near the luciferin binding site. Further, peptide model studies and additional investigations on the nature of the photoinactivation process strongly suggested that BPTC catalyzed the formation of singlet oxygen at the active site of the enzyme. We describe here an uncommon example of active site-directed photooxidation of an enzyme by singlet oxygen.     

Suppository administration of chemotherapeutic drugs with concomitant radiation for rectal cancer

PURPOSE: Preoperative radiation with combined chemotherapy is effective in shrinking advanced rectal cancer locally and facilitating subsequent surgery. Suppository delivery of 5-fluorouracil is associated with less toxicity and higher rectal tissue concentrations than intravenous administration. This prompted us to evaluate suppository and intravenous administration of 5-fluorouracil and mitomycin C with concomitant radiation to determine associated toxicity. METHODS: Rectal, liver, lymph node, and lung tissue and systemic and portal blood were collected serially from male Sprague Dawley rats to determine drug concentrations following suppository or intravenous delivery of 5-fluorouracil or mitomycin C. Thirty-six animals were randomly assigned to treatment groups and received 5-fluorouracil suppositories, mitomycin C suppositories, or an equivalent intravenous dose of 5-fluorouracil or mitomycin C 30 minutes before radiation therapy. Before and 3, 6, 10, and 15 days following this treatment, blood was collected, colonoscopy was performed, and rectal tissue was harvested for histologic examination. RESULTS: Mitomycin C suppository was significantly less toxic compared with intravenous delivery, and higher rectal tissue concentrations were observed from 10 to 30 minutes (P < 0.05). Compared with intravenous 5-fluorouracil administration and radiation, 5-fluorouracil suppository and radiation resulted in additive myelosuppression at day 6 (P < 0.05) with rapid recovery. CONCLUSIONS: 5-Fluorouracil and mitomycin C suppository delivery combined with radiation causes less systemic toxicity and is more effective than intravenous administration.     

Multi-angle Imaging SpectroRadiometer (MISR) instrument descriptionand experiment overview

The Multi-angle Imaging SpectroRadiometer (MISR) instrument is scheduled for launch aboard the first of the Earth Observing System (EOS) spacecraft, EOS-AM1. MISR will provide global, radiometrically calibrated, georectified, and spatially coregistered imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. Algorithms specifically developed to capitalize on this measurement strategy will be used to retrieve geophysical products for studies of clouds, aerosols, and surface radiation. This paper provides an overview of the as-built instrument characteristics and the application of MISR to remote sensing of the Earth     

Tissue equivalent vessel phantoms for intravascular ultrasound

The presence of the non-selective protein kinase C (PKC) inhibitors, staurosporine (100 nM) and polymyxin B (100 microM) in cultured human RPE cells for more than 24 h triggers apoptotic death. Apoptosis is characterized by a diminishing number of cells, a labelling of nuclei by the TUNEL method and by observable morphological changes. An inhibitor of PKC and cyclic nucleotide-dependent protein kinases, 1-(5-isoquinolinesulphonyl)-2-methyl piperazine (H-7; 100 microM), was without effect, as was the specific PKC inhibitor, calphostin C (100 nM). The PKC-activating phorbol esters, phorbol-12-myristate-13-acetate (PMA; 1 microM) and phorbol-12,13-dibutyrate (PDB; 1 microM) and the non-tumour-promoting phorbol ester, 4 alpha-PMA (1 microM) were without effect, as was the diacyl glycerol analogue, 1,2-dioctanoyl-snglycerol (DOG; 10 microM). The PKC activators did not attenuate the apoptosis induced by staurosporine or polymyxin B. Furthermore, deprivation of glucose and oxygen (simulated ischemia) for 72 h induced apoptosis: this could be prevented by inclusion of 10% (v/v) foetal bovine serum (FBS) but not by a variety of PKC activators. Six PKC isoenzymes were shown to be present in RPE cells (alpha, beta 1, beta 2, delta, epsilon, E) and only the calcium-dependent cPKC levels changed after treatment with staurosporine or simulated ischaemia. Since only the less selective inhibitors of PKC induced apoptosis, it is suggested that PKC is not involved directly in the induction process of apoptosis in RPE cells. It is possible that the staurosporine and polymyxin B-induced effects of apoptosis in RPE cells are triggered by an unknown kinase-dependent pathway, but whether the 'ischaemia'-induced death is related to this same process remains to be elucidated.     

Developmental differences in episodic retrieval: The role of differences in concept representations in semantic memory.

Developmental differences in the relative salience of features in concept representations in semantic memory and their contributions to differences in cued recall were examined in two experiments. For second graders, fifth graders, and college students, acquisition encoding of cue–target noun pair information was constrained by means of defining-, characteristic-, category-, and incidental-feature orienting questions. At retrieval, the encoding of cue information alone was constrained (Experiment 1) within subjects by means of the same (e.g., defining at acquisition and defining at retrieval) or related (e.g., defining at acquisition and characteristic at retrieval) retrieval questions or was unconstrained (Experiment 2). In both experiments, the acquisition presentation duration was manipulated (1 s or 5 s) in order to examine the spread of feature activation within concepts. The results showed that recall varied with feature salience, with the salience greatest for defining features. In addition, the results suggested that the relative salience of defining features was at least as great for the children as for the adults. The results offer no support for Keil and Batterman's (1984) hypothesis of a shift from characteristic to defining features in the development of word meaning representation in memory. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solid-state REDOR NMR distance measurements at the ligand site of a bacterial chemotaxis membrane receptor

The Escherichia coli serine receptor senses serine levels in the environment and transmits this information across the bacterial inner membrane to modulate a protein phosphorylation cascade which controls swimming behavior. Solid-state nuclear magnetic resonance (NMR) has been used to characterize specific structural features of the ligand binding site interactions in the intact, membrane-bound Ser receptor. Rotational-echo double-resonance (REDOR) experiments on [15N]Ser bound to a [1-13C]Phe-receptor preparation are used to measure distances between the ligand amino group and the carbonyls of two phenylalanine residues in the ligand binding pocket. The results indicate two 4.0 +/- 0.2 A distances, in excellent agreement with the X-ray crystal structure of a soluble fragment of the homologous aspartate receptor [Milburn et al. (1991) Science 254, 1342-1347]. These results confirm the similarity of the binding sites of the Asp and Ser receptors, and demonstrate the feasibility of using solid-state NMR measurements to obtain specific structural information on the 120 kDa intact receptor for probing transmembrane signaling mechanisms.