Oxidative Activity of Yeast Ero1p on Protein Disulfide Isomerase and Related Oxidoreductases of the Endoplasmic Reticulum

The sulfhydryl oxidase Ero1 oxidizes protein disulfide isomerase (PDI), which in turn catalyzes disulfide formation in proteins folding in the endoplasmic reticulum (ER). The extent to which other members of the PDI family are oxidized by Ero1 and thus contribute to net disulfide formation in the ER has been an open question. The yeast ER contains four PDI family proteins with at least one potential redox-active cysteine pair. We monitored the direct oxidation of each redox-active site in these proteins by yeast Ero1p in vitro. In this study, we found that the Pdi1p amino-terminal domain was oxidized most rapidly compared with the other oxidoreductase active sites tested, including the Pdi1p carboxyl-terminal domain. This observation is consistent with experiments conducted in yeast cells. In particular, the amino-terminal domain of Pdi1p preferentially formed mixed disulfides with Ero1p in vivo, and we observed synthetic lethality between a temperature-sensitive Ero1p variant and mutant Pdi1p lacking the amino-terminal active-site disulfide. Thus, the amino-terminal domain of yeast Pdi1p is on a preferred pathway for oxidizing the ER thiol pool. Overall, our results provide a rank order for the tendency of yeast ER oxidoreductases to acquire disulfides from Ero1p.     

Determinants of elevated healthcare utilization in patients with COPD

Background

Chronic obstructive pulmonary disease (COPD) imparts a substantial economic burden on western health systems. Our objective was to analyze the determinants of elevated healthcare utilization among patients with COPD in a single-payer health system.

Methods

Three-hundred eighty-nine adults with COPD were matched 1:3 to controls by age, gender and area of residency. Total healthcare cost 5 years prior recruitment and presence of comorbidities were obtained from a computerized database. Health related quality of life (HRQoL) indices were obtained using validated questionnaires among a subsample of 177 patients.

Results

Healthcare utilization was 3.4-fold higher among COPD patients compared with controls (p < 0.001). The "most-costly" upper 25% of COPD patients (n = 98) consumed 63% of all costs. Multivariate analysis revealed that independent determinants of being in the "most costly" group were (OR; 95% CI): age-adjusted Charlson Comorbidity Index (1.09; 1.01 - 1.2), history of: myocardial infarct (2.87; 1.5 - 5.5), congestive heart failure (3.52; 1.9 - 6.4), mild liver disease (3.83; 1.3 - 11.2) and diabetes (2.02; 1.1 - 3.6). Bivariate analysis revealed that cost increased as HRQoL declined and severity of airflow obstruction increased but these were not independent determinants in a multivariate analysis.

Conclusion

Comorbidity burden determines elevated utilization for COPD patients. Decision makers should prioritize scarce health care resources to a better care management of the "most costly" patients.     

Autaptic muscarinic self-excitation and nitrergic self-inhibition in neurons initiating Aplysia feeding are revealed when the neurons are cultured in isolation

Properties of a neuron may arise via endogenous mechanisms, or via interactions with other neurons. Culturing a neuron in isolation is a useful tool to distinguish between endogenous and circuit-derived properties. We identified two remarkable functional features of pattern initiator neurons B31/B32 in Aplysia when these neurons were cultured in isolation. These features were also present in situ, but were less prominent, and would have been missed had they not been observed first in the isolated cultured neurons. The properties are likely to be present in neurons of higher animals, but have not yet been observed. One feature was autaptic muscarinic self-excitation that contributes to the neuron's plateau potential, by which it initiates behavior. The other feature was the release of nitric oxide (NO) in the absence of spiking, which causes self-inhibition at rest. The nitrergic modulation of B31/B32 is likely to contribute to the control of feeding by dietary changes in the concentration of L: -arginine, the precursor from which NO is synthesized.     

Axoglial Adhesion by Cadm4 Regulates CNS Myelination

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Pepitope: epitope mapping from affinity-selected peptides

Identifying the epitope to which an antibody binds is central for many immunological applications such as drug design and vaccine development. The Pepitope server is a web-based tool that aims at predicting discontinuous epitopes based on a set of peptides that were affinity-selected against a monoclonal antibody of interest. The server implements three different algorithms for epitope mapping: PepSurf, Mapitope, and a combination of the two. The rationale behind these algorithms is that the set of peptides mimics the genuine epitope in terms of physicochemical properties and spatial organization. When the three-dimensional (3D) structure of the antigen is known, the information in these peptides can be used to computationally infer the corresponding epitope. A user-friendly web interface and a graphical tool that allows viewing the predicted epitopes were developed. Pepitope can also be applied for inferring other types of protein-protein interactions beyond the immunological context, and as a general tool for aligning linear sequences to a 3D structure. AVAILABILITY: http://pepitope.tau.ac.il/     

Vipera aspis venom reduces lethality and down-regulates tumor necrosis factor-α in a rat model of LPS-induced sepsis

Objectives: Sepsis and septic shock are major causes of morbidity and mortality in critically-ill patients. Sepsis constitutes the systemic response to infection, that is predominantly mediated by the pro-inflammatory cytokines TNF-α and IL-1β. Hence, cytokine modulation provides a promising target for the treatment of sepsis. In this work we evaluated the effect of a low-dose Vipera aspis venom (VAV) vaccine on survival and cytokine serum levels in a rat model of lipopolysaccharide (LPS)-induced septic shock. Methods: Adult male Wistar rats were given either VAV vaccine or saline, and 2 weeks later half of each group received LPS challenge, and were monitored for mortality, cytokine levels, blood count and chemistry. Results: Survival rate was significantly higher in venom-treated, compared to non-vaccinated septic rats. Furthermore, VAV treatment significantly reduced LPS-associated TNF-α and LDH, without affecting IL-6 and IL-10 levels, and modified WBC and platelet counts. Conclusions: Our data suggest that sub-toxic doses of VAV have a protective effect against LPS-induced septic shock that may be mediated, at least partially, by the modulated TNF-α activity. This study thus offers a novel therapeutic approach for the attenuation of bacteremia-induced septic shock through the modulation of a central pro-inflammatory cytokine by VAV vaccination in mammals.     

The suppressive effect of delta-1-tetrahydrocannabinol on the steroidogenic activity of rat granulosa cells in culture

In previous study the major psychoactive ingredient of marihuana (delta 1-THC) has been shown to inhibit ovarian prostaglandin synthesis when administered to normally cycling rats in the early afternoon of proestrus. These results suggested a direct suppressive effect of the drug on the ovary. The purpose of this study was to evaluate the effect of delta 1-THC on steroidogenesis in granulosa cells (GC) in vitro. Incubation of GC with delta 1-THC (10-50 microM) effectively inhibited LH-stimulatable progestin production. This suppressive effect was not abolished by washing the cells after 24 h of culture in the presence of delta 1-THC, indicating the irreversible nature of the blocking effect of delta 1-THC. By contrast, estradiol production following incubation of GC with testosterone (1 microgram/ml) was not inhibited by similar concentrations of delta 1-THC, thus suggesting that delta 1-THC does not inhibit aromatase activity in GC. In addition, delta 1-THC was shown to inhibit cAMP production as well as 125I-hCG binding capacity to GC. Administration of 8-Br-cAMP did not abolish the delta 1-THC-induced block, suggesting that the drug probably acts distal to the cAMP site of action.     

Control of knee coronal plane moment via modulation of center of pressure: a prospective gait analysis study

ObjectivesFootwear-generated biomechanical manipulations (e.g., wedge insoles) have been shown to reduce the magnitude of adduction moment about the knee. The theory behind wedged insoles is that a more laterally shifted location of the center of pressure reduces the distance between the ground reaction force and the center of the knee joint, thereby reducing adduction moment during gait. However, the relationship between the center of pressure and the knee adduction moment has not been studied previously. The aim of this study was to examine the association between the location of the center of pressure and the relative magnitude of the knee adduction moment during gait in healthy men.MethodsA novel foot-worn biomechanical device which allows controlled manipulation of the center of pressure location was utilized. Twelve healthy men underwent successive gait analysis testing in a controlled setting and with the device set to convey three different para-sagittal locations of the center of pressure: neutral, medial offset and lateral offset.ResultsThe knee adduction moment during the stance phase significantly correlated with the shift of the center of pressure from the functional neutral sagittal axis in the coronal plane (i.e., from medial to lateral). The moment was reduced with the lateral sagittal axis configuration and augmented with the medial sagittal axis configuration.ConclusionsThe study results confirm the hypothesis of a direct correlation between the coronal location of the center of pressure and the magnitude of the knee adduction moment.     

Effect of combined insecticide sprays and sanitation techniques on population dynamics of Ceratitis capitata (Diptera: Tephritidae) in the central mountains of Israel

We conducted an environmental manipulation study over a 7-km2 area to examine the effect of different control levels on the population dynamics of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in the central mountains of Israel. Adult male monitoring was carried out from spring to fall during 1988-1991 and year-round from 1994 to 2001. From 1995 to 1997, we manipulated the study area, imposing different levels of control by using a combination of insecticide sprays, tree pruning and removal, and fruit stripping. In the years preceding the manipulation, population dynamics was characterized by a peak summer population size in June-July, followed by a population decrease in August, leading to an early fall peak in September-October. If flies overwinter locally, we expected the intensive control to decrease the early summer population after the control. If flies do not overwinter locally, the control and sanitation activities should not decrease the population level in the following summer. During the entire period discussed, no flies were captured between January and May. The first appearance was recorded in late May or early June, reaching a peak in July. Regardless of control level and extent, the early summer peak remained unchanged during the entire study period, whereas the later fall peak decreased as host density decreased. We suggest that the first peak is the result of a seasonal reinvading population, whereas the later peak is governed by host availability and multiplication of the invading flies. The meaning and possible practical implications of our findings are discussed.