Diesel exhaust particles modulate the tight junction protein occludin in lung cells in vitro

Background  

Using an in vitro triple cell co-culture model consisting of human epithelial cells (16HBE14o-), monocyte-derived macrophages and dendritic cells, it was recently demonstrated that macrophages and dendritic cells create a transepithelial network between the epithelial cells to capture antigens without disrupting the epithelial tightness. The expression of the different tight junction proteins in macrophages and dendritic cells, and the formation of tight junction-like structures with epithelial cells has been demonstrated. Immunofluorescent methods combined with laser scanning microscopy and quantitative real-time polymerase chain reaction were used to investigate if exposure to diesel exhaust particles (DEP) (0.5, 5, 50, 125 μg/ml), for 24 h, can modulate the expression of the tight junction mRNA/protein of occludin, in all three cell types.     

Growth points in research on memory and hippocampus.

We present an overview of two of our ongoing projects relating processes in the hippocampus to memory. We are trying to understand why retrograde amnesia occurs after damage to the hippocampus. Our experiments establish the generality of several new retrograde amnesia phenomena that are at odds with the consensus view of the role of the hippocampus in memory. We show in many memory tasks that complete damage to the hippocampus produces retrograde amnesia that is equivalent for recent and remote memories. Retrograde amnesia affects a much wider range of memory tasks than anterograde amnesia. Normal hippocampal processes can interfere with retention of a long-term memory stored outside the hippocampus. We conclude that the hippocampus competes with nonhippocampal systems during memory encoding and retrieval. Finally, we outline a project to understand and manipulate adult hippocampal neurogenesis in order to repair damaged hippocampal circuitry to recover lost cognitive functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dual function of the proliferating cell nuclear antigen (PCNA) in the response of human cells to UV damages

An auxiliary protein of DNA polymerases delta and epsilon, the proliferating cell nuclear antigen (PCNA), is necessary for efficient DNA replication in vivo and in vitro, and also for the repair synthesis in vitro, but its role in the excision repair of genome in vivo is not exactly established. In S-phase of unirradiated cells, PCNA is tightly bound to focal centers of DNA replication and is not removed by treatment with detergent Triton X-100, but is completely extracted from non-S-phase cells by the indicated detergent. It was shown earlier that after UV-irradiation PCNA could not be removed by the detergent even from non-S-phase cells. It was interpreted as the evidence of PCNA integration into the repair complex and of the participation of this protein in repair synthesis in vivo. In the present work the data were obtained indicating that the role of PCNA in cell response to UV-damage was not confined only to its possible involvement in repair synthesis. With the help of confocal microscopy it was established that in Triton X-100-extracted normal cells PCNA did not colocalize with the well known excision repair protein XPB/ERCC3, defective in cells from Xeroderma pigmentosum (complementation group B) patients. XPB-protein is induced by UV-irradiation in normal cells, and this induction is not observed in repair deficient cells. However, in such cells UV-light induces a detergent-resistant form of PCNA, and this form is obviously not connected with repair. It cannot be excluded that a rapid PCNA immobilization immediately after UV-irradiation of cells is needed for the facilitation of photochemical damage bypass during the subsequent replication of genome.     

Effect of antioxidant in endothelial cells exposed to oxidized low-density lipoproteins

Antioxidants such as probucol and alpha-tocopherol have been shown to attenuate the oxidation of low-density lipoproteins (LDL) and atherosclerotic lesions in animal models of atherosclerosis. The purpose of this study is to determine the protection effect of antioxidants on endothelial cells when exposed to oxidized and native LDL. In a cell-free system, we found that probucol, alpha-tocopherol, and ascorbic acid inhibited copper-induced LDL oxidation by a dose-dependent fashion (from 1 microM to 10 mM). In porcine aortic endothelial cells, antioxidants alone did not change basal endothelin-1 (ET-1) secretion. When porcine aortic endothelial cells were exposed to LDL and oxidized-LDL, both of them stimulated ET-1 secretion dose-dependently, whereas oxidized-LDL elicited higher ET-1 secretion. However, probucol, alpha-tocopherol, and ascorbic acid did not prevent LDL or oxidized-LDL induced ET-1 secretion. Furthermore, nimodipine inhibited both of native and oxidized LDL induced ET-1 secretion. Since Ca2+ channel blocker reduced the elevation of induced ET-1 secretion, the [Ca2+]i is possibly involved for the regulation of ET-1 secretion. Our results suggest that antioxidants can only prevent the oxidation of LDL rather than oxidized and native LDL-induced ET-1 secretion in vascular endothelial cells. The increase in the [Ca2+]i of endothelial cells through the opening of voltage-dependent Ca2+ channels may be involved in the LDL-induced ET-1 release.     

Cerebral emboli and serum S100beta during cardiac operations

BACKGROUND: The glial protein S100beta has been used to estimate cerebral damage in a number of clinical settings. The purpose of this investigation was to determine the correlation between cerebral microemboli and S100beta levels during cardiac operations. METHODS: Transcranial Doppler ultrasonography was used to measure emboli in the right middle cerebral artery. Emboli counts (n = 111) were divided into five time periods: (1) incision to aortic cannulation; (2) aortic cannulation to cross-clamp onset; (3) cross-clamp onset to cross-clamp release; (4) cross-clamp release to decannulation; and (5) decannulation to chest closure. The level of S100beta (n = 156) was measured at baseline, at the end of cardiopulmonary bypass, then 150 and 270 minutes after cross-clamp release. RESULTS: The level of S100beta correlated with age, cardiopulmonary bypass time, cross-clamp time, and number of emboli at time period 2. Although cardiopulmonary bypass time was univariately associated with S100beta level, it became nonsignificant in a multivariable model that included age and cross-clamp time. CONCLUSIONS: The correlation of S100beta level with emboli measured during cannulation (time period 2) supports the hypothesis that cannulation is a high-risk time period for cerebral injury.     

Lipid patches in membrane protein oligomers: crystal structure of the bacteriorhodopsin-lipid complex

Heterogenous nucleation on small molecule crystals causes a monoclinic crystal form of bacteriorhodopsin (BR) in which trimers of this membrane protein pack differently than in native purple membranes. Analysis of single crystals by nano-electrospray ionization-mass spectrometry demonstrated a preservation of the purple membrane lipid composition in these BR crystals. The 2.9-A x-ray structure shows a lipid-mediated stabilization of BR trimers where the glycolipid S-TGA-1 binds into the central compartment of BR trimers. The BR trimer/lipid complex provides an example of local membrane thinning as the lipid head-group boundary of the central lipid patch is shifted by 5 A toward the membrane center. Nonbiased electron density maps reveal structural differences to previously reported BR structures, especially for the cytosolic EF loop and the proton exit pathway. The terminal proton release complex now comprises an E194-E204 dyad as a diffuse proton buffer.     

Anagrelide in control of myeloproliferative thrombocythemia: long-term experiences in 6 patients

Symptomatic or asymptomatic chronic elevation of platelet count can be observed in all forms of myeloproliferative disorders (MPD). Benefits and limitations of the traditional platelet-reducing agents, such as radioactive phosphorus, alkylating agents, hydroxyurea and interferon alpha, are well known and have been largely described. Anagrelide (Agrelin) is an additional newer drug with a selective platelet-lowering effect. We describe our own long-term experience in 6 patients with MPD who were treated with anagrelide as part of a compassionate-use protocol between April 1991 and August 1997. The median duration of therapy was 54 months (range 17 to 75 months), with an overall response rate of 100% (complete and partial response for at least 4 weeks). The initial median platelet count of 1211 x 10(9)/l (range 847 to 2050 x 10(9)/l) was reduced rapidly and lastingly to 570 x 10(9)/l (range 216 to 667 x 10(9)/l) at the time of the last control. Under treatment with anagrelide 4 of the 6 patients showed a reduction of disease-associated symptoms or complications. Adverse reactions were generally mild and transitory, and no interruption or cessation of therapy was required. Development of drug resistance or late adverse events were not observed. Treatment with anagrelide is effective, safe and in our opinion easy to administer. It also appears to be suitable for long-term administration.     

Potential benefits of estrogens and progestogens on breast cancer

Comparatively few studies have examined the effects of methadone given during a clinical detoxification programme. Furthermore, their results are different especially because of changing drop-out rates. This study was carried out on a drug-detoxification ward and investigated the effects of methadone given to alleviate withdrawal symptoms. Comparisons were undertaken with patients withdrawn during a one-year period before methadone was available. No significant difference was found between drop-out rates of patients with methadone-supported detoxification (n = 113, drop-out rate: 41.6%) and patients who did not receive methadone during detoxification (n = 108, drop-out rate: 37.0%). Nevertheless the drop-out rate in the first three days of withdrawal was reduced from 15.7% to 8.0%. On average the critical drop-out moment shifted from 5.3 days to 10.1 days. Interpretations of these findings should take into account, that the number of patients who underwent a voluntary detoxification programme for the first time was nearly doubled after methadone was offered on the ward and, additionally, many more patients tried to withdraw from methadone taken within an outpatient methadone-maintenance programme.