Effect of ß-glucans on rainbow trout (Oncorhynchus mykiss) IgM+ B cells.

ß-glucans are carbohydrates present in the cell wall of many fungi, which are often used as immunostimulants in feeds for farmed species. Their capacity to activate innate immune responses directly acting on innate cell populations has been widely documented in fish. However, whether they can affect the functionality of adaptive immune cells has been scarcely explored. In this context, in the current work, we have determined the effects of ß-glucans on rainbow trout blood IgM+ B cells in the presence or absence of 2,4,6-trinitrophenyl hapten conjugated to lipopolysaccharide (TNP-LPS), a model antigen. For this, rainbow trout peripheral blood leukocytes were incubated with different doses of ß-glucans or media alone in the presence or absence of TNP-LPS for 48 h. The size, levels of expression of surface MHC II, antigen processing and phagocytic capacities and proliferation of IgM+ B cells were then studied by flow cytometry. The number of IgM-secreting cells in the cultures was also estimated by ELISpot. ß-glucans significantly decreased the levels of surface MHC II expression and the antigen processing capacities of these cells, especially in the presence of TNP-LPS, while they increased their phagocytic activity. On their own, ß-glucans slightly activated the proliferation of IgM+ B cells but reduced that induced by TNP-LPS. In contrast, ß-glucans significantly increased the number of cells secreting IgM in the cultures. This effect of ß-glucans on the IgM-secreting capacity of B cells was also confirmed through a feeding experiment, in which the IgM-secreting capacity of blood leukocytes obtained from fish fed a ß-glucan-supplemented diet for one month was compared to that of leukocytes obtained from fish fed a control diet. Altogether, these findings contribute to increase our knowledge regarding the effects of ß-glucans on fish adaptive responses.

Yersinia ruckeri infection activates local skin and gill B cell responses in rainbow trout.

Teleost fish lack organized structures in mucosal tissues such as those of mammals, but instead contain dispersed B and T cells with the capacity to respond to external stimuli. Nonetheless, there is still a great lack of knowledge regarding how B cells differentiate to plasmablasts/plasma cells in these mucosal surfaces. To contribute to a further understanding of the mechanisms through which fish mucosal B cells are activated, in the current study, we have studied the B cell responses in the skin and gills of rainbow trout (Oncorhynchus mykiss) exposed to Yersinia ruckeri. We have first analyzed the transcription levels of genes related to B cell function in both mucosal surfaces, and in spleen and kidney for comparative purposes. In a second experiment, we have evaluated how the infection affects the presence and size of B cells in both skin and gills, as well as the presence of plasmablasts secreting total or specific IgMs. The results obtained in both experiments support the local differentiation of B cells to plasmablasts/plasma cells in the skin and gills of rainbow trout in response to Y. ruckeri. Interestingly, these plasmablasts/plasma cells were shown to secrete specific IgMs as soon as 5 days after the exposure. These findings contribute to a further understanding of how B cells in the periphery respond to immune stimulation in teleost fish.

Renal release of N-acetyl-seryl-aspartyl-lysyl-proline is part of an antifibrotic peptidergic system in the kidney.

The antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is released from thymosin-ß4 (Tß4) by the meprin-α and prolyl oligopeptidase (POP) enzymes and is hydrolyzed by angiotensin-converting enzyme (ACE). Ac-SDKP is present in urine; however, it is not clear whether de novo tubular release occurs or if glomerular filtration is the main source. We hypothesized that Ac-SDKP is released into the lumen of the nephrons and that it exerts an antifibrotic effect. We determined the presence of Tß4, meprin-α, and POP in the kidneys of Sprague-Dawley rats. The stop-flow technique was used to evaluate Ac-SDKP formation in different nephron segments. Finally, we decreased Ac-SDKP formation by inhibiting the POP enzyme and evaluated the long-term effect in renal fibrosis. The Tß4 precursor and the releasing enzymes meprin-α and POP were expressed in the kidneys. POP enzyme activity was almost double that in the renal medulla compared with the renal cortex. With the use of the stop-flow technique, we detected the highest Ac-SDKP concentrations in the distal nephron. The infusion of a POP inhibitor into the kidney decreased the amount of Ac-SDKP in distal nephron segments and in the proximal nephron to a minor extent. An ACE inhibitor increased the Ac-SDKP content in all nephron segments, but the increase was highest in the distal portion. The chronic infusion of a POP inhibitor increased kidney medullary fibrosis, which was prevented by Ac-SDKP. We conclude that Ac-SDKP is released by the nephron and is part of an important antifibrotic system in the kidney.

The anti-inflammatory peptide Ac-SDKP is released from thymosin-ß4 by renal meprin-α and prolyl oligopeptidase.

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a natural tetrapeptide with anti-inflammatory and antifibrotic properties. Previously, we have shown that prolyl oligopeptidase (POP) is involved in the Ac-SDKP release from thymosin-ß4 (Tß4). However, POP can only hydrolyze peptides shorter than 30 amino acids, and Tß4 is 43 amino acids long. This indicates that before POP hydrolysis takes place, Tß4 is hydrolyzed by another peptidase that releases NH2-terminal intermediate peptide(s) with fewer than 30 amino acids. Our peptidase database search pointed out meprin-α metalloprotease as a potential candidate. Therefore, we hypothesized that, prior to POP hydrolysis, Tß4 is hydrolyzed by meprin-α. In vitro, we found that the incubation of Tß4 with both meprin-α and POP released Ac-SDKP, whereas no Ac-SDKP was released when Tß4 was incubated with either meprin-α or POP alone. Incubation of Tß4 with rat kidney homogenates significantly released Ac-SDKP, which was blocked by the meprin-α inhibitor actinonin. In addition, kidneys from meprin-α knockout (KO) mice showed significantly lower basal Ac-SDKP amount, compared with wild-type mice. Kidney homogenates from meprin-α KO mice failed to release Ac-SDKP from Tß4. In vivo, we observed that rats treated with the ACE inhibitor captopril increased plasma concentrations of Ac-SDKP, which was inhibited by the coadministration of actinonin (vehicle, 3.1 ± 0.2 nmol/l; captopril, 15.1 ± 0.7 nmol/l; captopril + actinonin, 6.1 ± 0.3 nmol/l; P < 0.005). Similar results were obtained with urinary Ac-SDKP after actinonin treatment. We conclude that release of Ac-SDKP from Tß4 is mediated by successive hydrolysis involving meprin-α and POP.

N-Acetyl-Seryl-Aspartyl-Lysyl-Proline: mechanisms of renal protection in mouse model of systemic lupus erythematosus.

Systemic lupus erythematosus is an autoimmune disease characterized by the development of auto antibodies against a variety of self-antigens and deposition of immune complexes that lead to inflammation, fibrosis, and end-organ damage. Up to 60% of lupus patients develop nephritis and renal dysfunction leading to kidney failure. N-acetyl-seryl-aspartyl-lysyl-proline, i.e., Ac-SDKP, is a natural tetrapeptide that in hypertension prevents inflammation and fibrosis in heart, kidney, and vasculature. In experimental autoimmune myocarditis, Ac-SDKP prevents cardiac dysfunction by decreasing innate and adaptive immunity. It has also been reported that Ac-SDKP ameliorates lupus nephritis in mice. We hypothesize that Ac-SDKP prevents lupus nephritis in mice by decreasing complement C5-9, proinflammatory cytokines, and immune cell infiltration. Lupus mice treated with Ac-SDKP for 20 wk had significantly lower renal levels of macrophage and T cell infiltration and proinflammatory chemokine/cytokines. In addition, our data demonstrate for the first time that in lupus mouse Ac-SDKP prevented the increase in complement C5-9, RANTES, MCP-5, and ICAM-1 kidney expression and it prevented the decline of glomerular filtration rate. Ac-SDKP-treated lupus mice had a significant improvement in renal function and lower levels of glomerular damage. Ac-SDKP had no effect on the production of autoantibodies. The protective Ac-SDKP effect is most likely achieved by targeting the expression of proinflammatory chemokines/cytokines, ICAM-1, and immune cell infiltration in the kidney, either directly or via C5-9 proinflammatory arm of complement system.

First Report of Umbel Browning and Stem Necrosis Caused by Diaporthe angelicae on Carrot in France.

In 2011, carrot (Daucus carota L.) seed production occurred on 2,900 ha, which accounts for approximately 25% of the area devoted to the production of vegetable fine seeds. Since 2007, symptoms of umbel browning have been regularly observed in carrot production areas located in the central region. Initially, triangular necrotic lesions appeared on carrot umbels that later spread to the entire umbels and often progressed to the stems. Diseased umbels became dried prematurely, compromising seed development. The loss in seed production was estimated at approximately 8% of the harvested carrot umbels during the cropping seasons of spring and summer 2007 and 2008 in France. In collaboration with seed companies, diseased carrot stems were collected from seven fields of seed production (eight plants per field) and a fungus was isolated from the tissue. The cultures were grown on malt (2%) agar (1.5%) medium and incubated for 2 weeks at 22°C in darkness. Young fungal colonies were white and a brownish green pigmentation developed when the colonies became older. The same color was observed from the top and on the reverse of the colonies. To induce sporulation, isolates were grown on water agar (1.5%) medium in the presence of carrot stem fragments for 1 week at 22°C in darkness, followed by 1 week at 22°C in white light under a 16-h photoperiod. Pycnidia were produced on stem fragments and contained alpha and beta conidia typical of the genus Diaporthe (2). Alternatively, pycnidia were also obtained on malt agar medium after 2 weeks of culture at 25°C in white light under a 12-h photoperiod. The size of alpha and beta conidia was 6.3 ± 0.5 × 2.3 ± 0.4 µm and 23.3 ± 1.8 × 0.9 ± 0.2 µm, respectively (n = 170). In order to confirm the identification at the genus level and determine the species, DNA was extracted from the mycelium of three representative isolates and the ITS regions of the ribosomal DNA were amplified using universal primers (1). The sequences of the amplified products (GenBank Accession Nos. KF240772 to KF240774) were 100% identical with the ITS sequence of a Diaporthe angelicae isolate deposited in the NCBI database (CBS 111592 isolate, KC343027). To confirm pathogenicity, the three isolates of D. angelicae were inoculated on carrot umbels in the greenhouse. A total of nine plants were inoculated (three plants per isolate). Using a micropipette, 10 µl of a conidial suspension containing alpha and beta conidia (105 conidia mL-1) were deposited at the base of the primary umbel and two secondary umbels, which were wounded before inoculation using a scalpel blade. Seven inoculated plants developed triangular, necrotic lesions that were typical umbel browning. D. angelicae was re-isolated on malt agar medium from the inoculated diseased carrot umbels. To our knowledge, this is the first report of D. angelicae in carrot cultivated for seed production in France. The disease resembles the lesions described in the Netherlands in 1951 on carrot inflorescence caused by Phomopsis dauci (3). In future experiments, it would be crucial to precisely determine if D. angelicae could be transmitted to the seeds. References: (1) M. A. Innis et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (2) J. M. Santos and A. J. L. Philips. Fungal Divers. 34:111, 2009. (3) J. A. von Arx. Eur. J. Plant Pathol. 57:44, 1951.

The VWF/LRP4/αVß3-axis represents a novel pathway regulating proliferation of human vascular smooth muscle cells.

AIMS: Von Willebrand factor (VWF) is a plasma glycoprotein involved in primary haemostasis, while also having additional roles beyond haemostasis namely in cancer, inflammation, angiogenesis, and potentially in vascular smooth muscle cell (VSMC) proliferation. Here, we addressed how VWF modulates VSMC proliferation and investigated the underlying molecular pathways and the in vivo pathophysiological relevance. METHODS AND RESULTS: VWF induced proliferation of human aortic VSMCs and also promoted VSMC migration. Treatment of cells with a siRNA against αv integrin or the RGT-peptide blocking αvß3 signalling abolished proliferation. However, VWF did not bind to αvß3 on VSMCs through its RGD-motif. Rather, we identified the VWF A2 domain as the region mediating binding to the cells. We hypothesized the involvement of a member of the LDL-related receptor protein (LRP) family due to their known ability to act as co-receptors. Using the universal LRP-inhibitor receptor-associated protein, we confirmed LRP-mediated VSMC proliferation. siRNA experiments and confocal fluorescence microscopy identified LRP4 as the VWF-counterreceptor on VSMCs. Also co-localization between αvß3 and LRP4 was observed via proximity ligation analysis and immuno-precipitation experiments. The pathophysiological relevance of our data was supported by VWF-deficient mice having significantly reduced hyperplasia in carotid artery ligation and artery femoral denudation models. In wild-type mice, infiltration of VWF in intimal regions enriched in proliferating VSMCs was found. Interestingly, also analysis of human atherosclerotic lesions showed abundant VWF accumulation in VSMC-proliferating rich intimal areas. CONCLUSION: VWF mediates VSMC proliferation through a mechanism involving A2 domain binding to the LRP4 receptor and integrin αvß3 signalling. Our findings provide new insights into the mechanisms that drive physiological repair and pathological hyperplasia of the arterial vessel wall. In addition, the VWF/LRP4-axis may represent a novel therapeutic target to modulate VSMC proliferation.

Expression of α-defensin 1-3 in T cells from severe cutaneous drug-induced hypersensitivity reactions.

BACKGROUND: Cytotoxic T cells seem to be the main effector cells in Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). However, recent data support a role of the innate immune system in the etiopathology of drug-induced cutaneous reactions. In this study, we analyzed the expression of α-defensins 1-3 in mononuclear cells from patients with SJS/TEN, drug-induced maculopapular exanthema (MPE), and healthy donors. METHODS: DEFA1A3 gene expression was analyzed by quantitative and end-point RT-PCR. Intracellular flow cytometry, immunofluorescence and immunohistochemistry were carried out to verify α-defensin 1-3 protein expression in mononuclear cells from peripheral blood and skin infiltrates. α-Defensin 1-3 concentration was evaluated in plasma and blister fluid samples by ELISA. RESULTS: We herein describe DEFA1A3 gene expression in peripheral blood mononuclear cells (PBMCs) from patients with drug-induced cutaneous diseases. Gene expression analysis unveiled transcription in CD4 and CD8 peripheral blood T cells. Protein expression was confirmed by intracellular flow cytometry in mononuclear cells from the patients, including monocytes, NK cells, and T cells from peripheral blood and blister fluid. Further analysis of protein content by flow cytometry revealed higher protein levels in CD56(+) CD3(+) lymphocytes from patients with SJS/TEN when compared to MPE and healthy donors. Immunohistological analysis was used to confirm expression in dermal infiltrates. α-Defensin levels were estimated by ELISA to be 3- to 175-fold higher in blister fluid when compared to simultaneously drawn plasma samples. CONCLUSION: Upregulation of innate immune molecules such as α-defensins 1-3 in T cells from patients with SJS/TEN may be involved in the etiopathology of these life-threatening diseases induced by medications.

Differential gene expression in drug hypersensitivity reactions: induction of alarmins in severe bullous diseases.

BACKGROUND: Delayed hypersensitivity reactions to drugs can be life-threatening and constitute a growing problem in clinical practice. Although drug-specific T cells seem to be involved, the cellular and molecular bases of their aetiopathology are not fully understood. OBJECTIVES: To study the molecular mechanisms underlying the pathogenesis and the clinical heterogeneity of cutaneous delayed hypersensitivity reactions to drugs. MATERIALS AND METHODS: We characterized the gene expression profiles of peripheral blood mononuclear cells (PBMCs) isolated from patients during the acute phase of the reaction and upon resolution of clinical symptoms using a cDNA array technology. Low-density arrays were used to confirm differential expression of selected genes during the acute disease in patients and to compare gene expression in patients and exposed control donors by quantitative real-time polymerase chain reaction. RESULTS: Eighty-five genes were found to be differentially expressed during the acute phase of cutaneous drug-induced delayed hypersensitivity reactions. Furthermore, 92 genes with distinct expression patterns in severe and benign diseases during the acute phase were identified. PBMCs from patients with severe bullous diseases showed a characteristic gene expression pattern with lower expression of genes encoding T cell-specific proteins and high expression of cell cycle-related genes and genes coding for inflammatory-related mediators among which several endogenous damage-associated molecular patterns (DAMPs) or alarmins were found. CONCLUSIONS: Distinct gene expression profiles in PMBCs define benign and severe clinical entities. Overexpression of endogenous DAMPs in Stevens-Johnson syndrome and toxic epidermal necrolysis suggest that drugs can trigger the alarmin system in sensitized patients leading to life-threatening diseases.

Acute generalized exanthematous pustulosis due to tetrazepam.

Tetrazepam is a benzodiazepine that is widely used in Spain as a muscle relaxant, with occasional cutaneous side effects. We report a patient who developed a generalized pruriginous cutaneous reaction compatible with acute generalized exanthematous pustulosis (AGEP) due to tetrazepam. Patch tests with bromazepam, diazepam, and tetrazepam were negative at 48 and 72 hours; however, the tetrazepam patch showed a positive reaction at 10 days. Immunohistochemical studies revealed a mononuclear infiltrate composed of CD4+ and CD8+ T lymphocytes. Analysis of interleukin (IL) 8 expression by quantitative polymerase chain reaction revealed increased IL-8 mRNA levels in patch test-positive skin. Lymphoblast transformation test (LTT) was positive with tetrazepam but not with diazepam. Positive patch test and LTT suggested that tetrazepam-specific lymphocytes might be responsible for a T cell-mediated reaction. These results support previous data suggesting an important role for IL-8 and drug-specific T cells in the pathogenesis ofAGEP and imply that the reaction was specific to tetrazepam with no cross-reactivity to other benzodiazepines.

[How to determine the upper level of instrumentation in thoracic adolescent idiopathic scoliosis: a prospective study of 103 patients]. / Planification du niveau supérieur d'arthrodèse dans les scolioses idiopathiques thoraciques de l'adolescent: étude prospective de 103 cas.

PURPOSE OF THE STUDY: Determining the level of fusion remains a highly debated topic in adolescent isiopathic scoliosis. The King and Lenke classifications are used, but have their limitations, particularly the weak interobserver reproducibility. We describe the method we use which is independent of the anatomic classification, based on the predictable reduction of the different curvatures. The goal is to achieve good balance of T1 and the shoulders and reestablish spinal balance in the frontal and sagittal planes. The purpose of this work was to assess the midterm results of this strategy for determining the upper level of instrumentation. MATERIAL AND METHODS: The series included 103 adolescents who underwent surgery for idiopathic thoracic scoliosis using a posterior segmental instrumentation. The upper level of fusion was determined by analyzing the rigidity of the proximal curvature and the inclination of T1 and the shoulder. X-rays (preop, postop, last follow-up) were digitalized for computer processing. Comparisons were made with the t test for paired series. RESULTS: Mean age at surgery was 15.2+/-1.7 years (range 10.8-19.3). Mean follow-up was 30.2 months. The clavicular angle and T1 inclination were improved significantly, both for the unique thoracic curvatures and for double thoracic curvatures. No correlation could be found between T1 inclination and shoulder balance. At last follow-up, 86.5% of the patients satisfied all balance criteria. DISCUSSION: The results of our method, which was carried out fully in 97% of patients, are encouraging and show that systematic instrumentation of the entire proximal curvature is not warranted for double thoracic curvatures. The long-term consequences for the residual T1 inclination remain to be assessed.

Association of neonatal myasthenia gravis with antibodies against the fetal acetylcholine receptor.

The specificities of autoantibodies directed against the acetylcholine receptor (AChR) for embryonic and adult muscle AChR were studied in 22 mothers with myasthenia gravis (MG) and in their newborns using human fetus and normal adult muscle AChR preparations. 12 mothers had transmitted MG to their neonates with, in three cases, antenatal injury. A clear correlation was found between occurrence of neonatal MG (NMG) and the high overall level of anti-AChR antibodies (embryonic or adult muscle AChR). However, a strong correlation was also found between occurrence of NMG and the ratio of anti-embryonic AChR to anti-adult muscle (Te/Ta) AChR antibodies (P < 0.0002). Taken together, these data suggest that autoantibodies directed against the embryonic form of the AChR could play a predominant role in the pathogenesis of NMG. Paradoxically, the three cases with antenatal injury presumably the most severe form of NMG, were not associated with high Te/Ta. At the clinical level, these observations could prove helpful in the prediction of transmission of NMG.

[Superior mesenteric artery syndrome following correction of spinal deformity: case report and review of the literature]. / Syndrome de la pince aorto-mésentérique après correction d'une déformation rachidienne.

Superior mesenteric artery syndrome is a rare complication which can develop after surgical correction of a spinal deformity. The syndrome is caused by an extrinsic compression on the third portion of the duodenum by the aorta posteriorly and the mesenteric artery anteriorly. We report here a case of aortomesenteric compression of the duodenum secondary to surgical correction of lower thoracic scoliosis in a 19-year-old female. The patient presented vomiting and intestinal obstruction ten days after spinal surgery. Treatment consisted in exclusive parenteral nutrition followed by careful surveillance and progressive reintroduction of oral food intake to avoid unnecessary surgery. Young thin subjects are predominantly exposed to this type of complication. The body mass index is a good indication to identify subjects at risk. Symptoms of upper gastrointestinal obstruction develop seven to ten days after surgery. Diagnosis is based on transit studies using a hydroluble contrast agent which reveals major gastric dilation and a clear interruption of the transit at the level of the third duodenum as well as retrograde peristaltism. Medical treatment should be undertaken first and is effective in the large majority of cases. Surgery may be proposed only in the event of failure. Recurrence is exceptional. Early diagnosis, delivery of clear information for the patient and family and multidisciplinary management are important points to consider for proper care for this complication which if neglected can become life-threatening.

Molecular Mechanisms of Noncanonical Autophagy.

Macroautophagy is a lysosomal catabolic process that maintains the homeostasis of eukaryotic cells, tissues, and organisms. Macroautophagy plays important physiological roles during development and aging processes and also contributes to immune responses. The process of macroautophagy is compromised in diseases, such as cancer, neurodegenerative disorders, and diabetes. The autophagosome, the double-membrane-bound organelle that sequesters cytoplasmic material to initiate macroautophagy, is formed by the hierarchical recruitment of about 15 autophagy-related (ATG) proteins and associated proteins, such as DFCP1, AMBRA1, the class III phosphatidyl-inositol 3-kinase VPS34, and p150/VPS15. Evidence suggests that in addition to the canonical pathway, noncanonical pathways that do not require the entire repertoire of ATGs can also result in formation of autophagosomes. Here we will discuss recent discoveries concerning the molecular regulation of these noncanonical forms of macroautophagy and their potential roles in cellular responses to stressful situations.

Atrial fibrillation is associated with hypermethylation in human left atrium, and treatment with decitabine reduces atrial tachyarrhythmias in spontaneously hypertensive rats.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. As the molecular mechanisms underlying the pathology are largely unknown, this cardiac arrhythmia remains difficult to treat. To identify specific molecular actors involved in AF, we have performed a transcriptomic analysis on left atrium (LA) from patients with valvular heart disease with or without AF. We showed that 1627 genes had altered basal expression level in LA tissue of AF patients compared with the control group. The significantly enriched gene ontology biological process "anatomical structure morphogenesis" contained the highest number of genes in line with changes in structure that occur when the human heart remodels following AF development (ie, LA dilatation and interstitial fibrosis). We then focused the study on Pitx2 (paired-like homeodomain 2), being the most altered transcription factor in LA from AF patients and from which compelling evidence have indicated that its reduced expression can be considered as a marker for the disease. In addition, its expression was inversely correlated with LA size. We demonstrated that AF is associated with Pitx2 promoter hypermethylation both in humans and arrhythmic aging spontaneously hypertensive rats. Chronic administration of a DNA methylation inhibitor (ie, 5-Aza-2'-deoxycitidine) improved ECG arrhythmic profiles and superoxide dismutase activities and reduced fibrosis in the left ventricle of spontaneously hypertensive rats. Taken together, these data support the notion that AF is associated with epigenetic changes in LA and provide a proof-of-concept that hypomethylating agents have to be considered in the treatment of atrial arrhythmias.

Effects of N-acetyl-seryl-asparyl-lysyl-proline on blood pressure, renal damage, and mortality in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease with a high prevalence of hypertension. NZBWF1 (SLE-Hyp) mice develop hypertension that can be prevented by modulating T cells. The peptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) decreases renal damage and improves renal function in a model of SLE without hypertension (MRL/lpr). However, it is not known whether Ac-SDKP prevents hypertension in NZBWF1 mice. We hypothesized that in SLE-Hyp, Ac-SDKP prevents hypertension and renal damage by modulating T cells. Animals were divided into four groups: (1) control + vehicle, (2) control + Ac-SDKP, (3) SLE + vehicle, and (4) SLE + Ac-SDKP Systolic blood pressure (SBP), albuminuria, renal fibrosis, and T-cell phenotype were analyzed. SBP was higher in SLE compared to control mice and was not decreased by Ac-SDKP treatment. Half of SLE mice developed an acute and severe form of hypertension accompanied by albuminuria followed by death. Ac-SDKP delayed development of severe hypertension, albuminuria, and early mortality, but this delay did not reach statistical significance. Ac-SDKP prevented glomerulosclerosis, but not interstitial fibrosis in SLE-Hyp mice. SLE-Hyp mice showed a decrease in helper and cytotoxic T cells as well as an increase in double negative lymphocytes and T helper 17 cells, but these cells were unaffected by Ac-SDKP In conclusion, Ac-SDKP prevents kidney damage, without affecting blood pressure in an SLE animal model. However, during the acute relapse of SLE, Ac-SDKP might also delay the manifestation of an acute and severe form of hypertension leading to early mortality. Ac-SDKP is a potential tool to treat renal damage in SLE-Hyp mice.

ADM1 application for tuning and performance analysis of a multi-model observer-based estimator.

Anaerobic digestion model no.1 (ADM1) was used for tuning and performance analysis of the multi-model observer based estimator (mmOBE). The mmOBE was based on the variable structure model (VSM) of the anaerobic digestion model, which consists of several local submodels, each of which describes a typical process state. Depending on the hydraulic retention time, ADM1 simulated the methanogenic, organic overload, and acidogenic states of the process. These simulations allowed for optimising tunable parameters of the mmOBE. Owing to relatively slow process dynamics, a data acquisition interval as large as one day was sufficient to obtain acceptable accuracy. The simulations of mmOBE performance showed excellent rate of mmOBE convergence to ADM1 outputs. Moreover, mmOBE successfully estimated key kinetic parameters, such as maximal transformation rates of CODs, VFAs, and methane. These estimations can be used in the development of the advanced knowledge-based process system, which uses both available measurements and estimations of key kinetic parameters for extended diagnosis of failures and process trend analysis.

On-line estimation of kinetic parameters in anaerobic digestion using observer-based estimators and multiwavelength fluorometry.

Observer-based estimators (OBE) were used for estimation of state variables and kinetic parameters in an anaerobic digestion (AD) process. A simplified first-order model with time-varying kinetic parameters was used to design an OBE for kinetic parameter estimation. This approach was validated on a laboratory-scale anaerobic reactor equipped with a multiwavelength fluorometer for on-line measurements of COD and VFA concentrations in the reactor effluent. The proposed estimators provide continuous adjustment of kinetic parameters and can be used for predictions of state variables between samples acquisition and during sensor failure.

Metabolic capacity for L-citrulline synthesis from ammonia in rat isolated colonocytes.

Ammonia is present at high concentration in the colon lumen and is considered a colon cancer suspect. Furthermore, ammonia usually eliminated by the liver in the ornithine cycle is considered highly toxic to cerebral function when present in excess in the blood plasma. Therefore, the metabolic pathways involved in ammonia metabolism in colonocytes were studied in the present study. Rat colonocytes were found equipped with low carbamoylphosphate synthase I activity, high ornithine carbamoyltransferase and arginase activities and low argininosuccinate synthase activity. High (10 and 50 mmol/l) NH4Cl concentrations but not low concentrations (1 and 5 mmol/l) were found able to increase respectively 3- and 10-fold the conversion of radioactive L-arginine to L-citrulline. In contrast, very low capacity for L-citrulline conversion to L-arginine is found in colonocytes. It is concluded that an incomplete ornithine cycle is operative in colonocytes which results in ammonia stimulated L-citrulline production. The contribution of this metabolic pathway in relation to ammonia detoxication by colonocytes is discussed.

Multi-wavelength fluorometry for anaerobic digestion process monitoring.

Applicability of multi-wavelength fluorometry for anaerobic digestion process monitoring was investigated in a 3.5 L upflow anaerobic sludge bed (UASB) lab-scale reactor. Both off-line and on-line monitoring of key process parameters was tested. Off-line emission spectra were measured at an angle of 90 degrees to the excitation beam using a cuvette. On-line measurements were carried out using a fiber optic probe in the external recirculation line of the digester. Fluorescence spectra were correlated to available analytical measurements to obtain partial least square regression models. An independent set of measurements was used to validate the regression models. Model estimations showed reasonable agreement with analytical measurements with multiple determination coefficients (R2) between 0.6 and 0.95. Results showed that offline fluorescence measurements can be used for fast estimation of anaerobic digestor effluent quality. At the same time, the on-line implementation of multi-wavelength fluorescence measurements can be used for realtime process monitoring and, potentially, for on-line process control.