Effect of lipopolysaccharide from periodontal pathogens on the production of tissue plasminogen activator and plasminogen activator inhibitor 2 by human gingival fibroblasts

Both tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 2 (PAI-2) are important proteolysis factors present in inflamed human periodontal tissues. The aim of the present study was to investigate the effect of lipopolysaccharide (LPS) on the synthesis: of t-PA and PAI-2 by human gingival fibroblasts (HGF). LPS from different periodontal pathogens including Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum were extracted by the hot phenol water method. The levels of t-PA and PAI-2 secreted into the cell culture media were measured by enzyme-linked immunosorbent assays (ELISA). The mRNA for t-PA and PAI-2 were measured by RT-PCR. The results showed t-PA synthesis was increased in response to all types of LPS studied and PAI-2 level was increased by LPS from A. actinomycetemcomitans and F. nucleatum, but not P. gingivalis. When comparing the effects of LPS from non-periodontal bacteria (Escherichia coli and Salmonella enteritidis) with the LPS from periodontal pathogens, we found that the ratio of t-PA to PAI-2 was greater following exposure of the cells to LPS from periodontal pathogens. The highest ratio of t-PA to PAI-2 was found in those cells exposed to LPS from P. gingivalis. These results indicate that LPS derived from periodontal pathogens may cause unbalanced regulation of plasminogen activator and plasminogen activator inhibitor by HGF and such an effect may, in part, contribute to the destruction of periodontal connective tissue through dysregulated pericellular proteolysis.

Differential Production of Macrophage Inflammatory Protein-1 alpha, Stromal-Derived Factor-1, and IL-6 by Human Cultured Periodontal Ligament and Gingival Fibroblasts Challenged With Lipopolysaccharide From P. gingivalis

Background: Fibroblasts are considered important cells in periodontitis. When challenged by different agents, they respond through the release of cytokines that participate in the inflammatory process. The aim of this study is to evaluate and compare the expression and production of macrophage inflammatory protein (MIP)-1 alpha, stromal-derived factor (SDF)-1, and interleukin (IL)-6 by human cultured periodontal ligament and gingival fibroblasts challenged with lipopolysaccharide (LPS) from Porphyromonas gingivalis. Methods: Fibroblasts were cultured from biopsies of gingival tissue and periodontal ligament of the same donors and used on the fourth passage. After confluence in 24-well plates, the culture medium alone (control) or with 0.1 to 10 mu g/ml of LPS from P. gingivalis was added to the wells, and after 1, 6, and 24 hours, the supernatant and the cells were collected and analyzed by enzyme-linked immunosorbent assay and real-time polymerase chain reaction, respectively. Results: MIP-1 alpha, SDF-1, and IL-6 protein production was significantly greater in gingival fibroblasts compared to periodontal ligament fibroblasts. IL-6 was upregulated in a time-dependent manner, mainly in gingival fibroblasts (P<0.05), which secreted more MIP-1 alpha in the lowest concentration of LPS used (0.1 mu g/ml). In contrast, a basal production of SDF-1 that was inhibited with the increase of LPS concentration was detected, especially after 24 hours (P<0.05). Conclusion: The distinct ability of the gingival and periodontal ligament fibroblasts to secrete MIP-1 alpha, SDF-1, and IL-6 emphasizes that these cells may differently contribute to the balance of cytokines in the LPS-challenged periodontium. J Periodontol 2010;81:310-317.

Effect of laser phototherapy on the release of fibroblast growth factors by human gingival fibroblasts

The effects of laser phototherapy on the release of growth factors by human gingival fibroblasts were studied in vitro. Cells from a primary culture were irradiated twice (6 h interval), with continuous diode laser [gallium-aluminum-arsenium (GaAlAs), 780 nm, or indium-gallium-aluminum-phosphide (InGaAlP),_660 nm] in punctual and contact mode, 40 mW, spot size 0.042 cm(2), 3 J/cm(2) and 5 J/cm(2) (3 s and 5 s, respectively). Positive [10% fetal bovine serum (FBS)] and negative (1%FBS) controls were not irradiated. Production of keratinocyte growth factor (KGF) and basic fibroblast growth factor (bFGF) was quantified by enzyme-linked immunosorbent assay (ELISA). The data were statistically compared by analysis of variance (ANOVA) followed by Tukey`s test (P a parts per thousand currency signaEuro parts per thousand 0.05). The characterization of the cell line indicated a mesenchymal nature. KGF release was similar in all groups, while that of bFGF was significantly greater (1.49-times) in groups treated with infra-red laser. It was concluded that increased production of bFGF could be one of the mechanisms by which infra-red laser stimulates wound healing.

On the decay rates of buffers in continuous flow lines

Consider a tandem system of machines separated by infinitely large buffers. The machines process a continuous flow of products, possibly at different speeds. The life and repair times of the machines are assumed to be exponential. We claim that the overflow probability of each buffer has an exponential decay, and provide an algorithm to determine the exact decay rates in terms of the speeds and the failure and repair rates of the machines. These decay rates provide useful qualitative insight into the behavior of the flow line. In the derivation of the algorithm we use the theory of Large Deviations.

Blocking systemic nitric oxide production alters neuronal activation in brain structures involved in cardiovascular regulation during polymicrobial sepsis

In a previous study, we concluded that overproduction of nitric oxide (NO) by inducible nitric Oxide synthase (iNOS) in the late phase of sepsis prevents hypothalamic activation, blunts vasopressin secretion and contributes to hypotension, irreversible shock and death. The aim of this follow-up study was to evaluate if the same neuronal activation pattern happens in brain structures related to cardiovascular functions. Male Wistar rats received intraperitoneal injections of aminoguanidine, an iNOS inhibitor, or saline 30 min before cecal ligation and puncture (CLP) or sham surgeries. The animals were perfused 6 or 24 h after the surgeries and the brains were removed and processed for Fos immunocytochemistry We observed an increase (P < 0.001) in c-fos expression 6 h after CLP in the area postrema (AP), nucleus of he tractus solitarius (NTS), ventral lateral medulla (VLM), locus coeruleus (LC) and parabrachial nucleus (PB). At 24 h after CLP, however, c-fos expression was strongly decreased in all these nuclei (P < 0.05), except for the VLM. Aminoguanidine reduced c-fos expression in the AP and NTS at 6 h after CLR but showed an opposite effect at 24 h, with an increase in the AP, NTS, and also in the VLM. No such effect was observed in the LC and PB at 6 or 24 h. In all control animals, c-fos expression was minimal or absent. We conclude that in the early phase of sepsis iNOS-derived NO may be partially responsible for the activation of brain structures related to cardiovascular regulation. During the late phase, however, this activation is reduced or abolished. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Continuous quantum measurement of two coupled quantum dots using a point contact: A quantum trajectory approach

We obtain the finite-temperature unconditional master equation of the density matrix for two coupled quantum dots (CQD's) when one dot is subjected to a measurement of its electron occupation number using a point contact (PC). To determine how the CQD system state depends on the actual current through the PC device, we use the so-called quantum trajectory method to derive the zero-temperature conditional master equation. We first treat the electron tunneling through the PC barrier as a classical stochastic point process (a quantum-jump model). Then we show explicitly that our results can be extended to the quantum-diffusive limit when the average electron tunneling rate is very large compared to the extra change of the tunneling rate due to the presence of the electron in the dot closer to the PC. We find that in both quantum-jump and quantum-diffusive cases, the conditional dynamics of the CQD system can be described by the stochastic Schrodinger equations for its conditioned state vector if and only if the information carried away from the CQD system by the PC reservoirs can be recovered by the perfect detection of the measurements.

Pharmacokinetics of ciprofloxacin in ICU patients on continuous veno-venous haemodiafiltration

Objectives: To investigate the pharmacokinetics of intravenous ciprofloxacin 200 mg every 8 h in critically ill patients on continuous veno-venous haemodiafiltration (CVVHDF), one form of continuous renal replacement therapy (CRRT). Design and setting: Open, prospective clinical study in a multidisciplinary, intensive care unit in a university-affiliated tertiary referral hospital. Patients: Sis critically ill patients with acute renal failure on CVVHDF. Interventions: Timed blood and ultrafiltrate samples were collected to allow pharmacokinetics and clearances to be calculated of initial and subsequent doses of 200 mg intravenous ciprofloxacin. CVVHD was performed with 1 l/h of dialysate and 2 l/h of predilution filtration solution, producing 3 lih of dialysis effluent. The blood was pumped at 200 ml/min using a Gambro BMM-10 blood pump through a Hospal AN69HF haemofilter,. Measurements and results: Ten pharmacokinetic profiles were measured. The CVVHDF displayed a urea clearance of 42 +/- 3 ml/min, and removed ciprofloxacin with a clearance of 37 +/- 7 ml/min. This rate was 2-2.5 greater than previously published for ciprofloxacin in other forms of CRRT. On average the CVVHDF was responsible for clearing a fifth of all ciprofloxacin eliminated (21 +/- 10%). The total body clearance of ciprofloxacin was 12.2 +/- 4.3 l/h. The trough concentration following the initial dose was 0.7 +/- 0.3 mg/l. The area under the plasma concentration time curves over a 24-h period ranged from 21 to 55 mg .h l(-1). Conclusions: Intravenous ciprofloxacin 600 mg/day in critically ill patients using this form of CRRT produced adequate plasma levels for many resistant microbes found in intensive care units.

Dynamics of a mesoscopic charge quantum bit under continuous quantum measurement

We present the conditional quantum dynamics of an electron tunneling between two quantum dots subject to a measurement using a low transparency point contact or tunnel junction. The double dot system forms a single qubit and the measurement corresponds to a continuous in time readout of the occupancy of the quantum dot. We illustrate the difference between conditional and unconditional dynamics of the qubit. The conditional dynamics is discussed in two regimes depending on the rate of tunneling through the point contact: quantum jumps, in which individual electron tunneling current events can be distinguished, and a diffusive dynamics in which individual events are ignored, and the time-averaged current is considered as a continuous diffusive variable. We include the effect of inefficient measurement and the influence of the relative phase between the two tunneling amplitudes of the double dot/point contact system.

The management of rice grown on raised beds with continuous furrow irrigation

A field experiment compared two rice (Oryza sativa L.) cropping systems: paddy or raised beds with continuous furrow irrigation; and trialled four cultivars: Starbonnet, Lemont, Amaroo and Ceysvoni, and one test line YRL39; that may vary in adaptation to growth on raised beds. The grain yield of rice ranged from 740 to 1250 g/m(2) and was slightly greater in paddy than on raised beds. Although there were early growth responses to fertilizer nitrogen on raised beds, the crop nitrogen content at maturity mostly exceeded 20 g/m(2) in both systems, so nitrogen was unlikely to have limited yield. Ceysvoni yielded best in both systems, a result of good post-anthesis growth and larger grain size, although its whole-grain mill-out percentage was poor relative to the other cultivars. Starbonnet and Lemont yielded poorly on raised beds, associated with too few tillers and too much leaf area. When grown on raised beds all cultivars experienced a delay in anthesis resulting in more tillers, leaf area and dry weight at anthesis, and probably a greater yield potential. The growth of rice after anthesis, however, was similar on raised beds and in paddy, so reductions in harvest index and grain size on raised beds were recorded. The data indicated that water supply was not a major limitation to rice growth on raised beds, but slower crop development was an issue that would affect the use of raised beds in a cropping system, especially in rice-growing areas where temperatures are too cool for optimal crop development. (C) 2001 Elsevier Science B.V. All rights reserved.

The mechanisms of combustion and continuous reactions during mechanical alloying

Some materials exhibit a combustion event during mechanical alloying, which results in the rapid transformation of reactants into products, while others show a slow transformation of reactants into products, In this paper, the continuous W + C --> WC reaction is compared to the Ti + C --> TiC combustion reaction. Rietveld refinement of X-ray diffraction patterns is used to show that these particular reactions proceed through different pathways, determined by crystallographic factors of the reactants. When a crystallographic relationship exists between the reactants and the products, such as that between W and WC, the product forms slowly over a period of time. In contrast, insertion of C into the Ti structure is associated with atomic rearrangements within the crowded lattice planes and the subsequent catastrophic failure of the reactant lattices results in combustion to form TiC. (C) 2001 Academic Press.