Regulation of peritoneal and systemic neutrophil-derived tumor necrosis factor-alpha release in patients with severe peritonitis: role of tumor necrosis factor-alpha converting enzyme cleavage

OBJECTIVE: Polymorphonuclear neutrophil (PMN) influx and peritoneal tumor necrosis factor (TNF)-alpha production are key host defense mechanisms during peritonitis. The aim of this study was to explore the potential interactions between TNF-alpha production and TNF-alpha converting enzyme (TACE) expression by PMN in the blood and peritoneum of patients with severe peritonitis. DESIGN: A prospective study. SETTING: A surgical adult intensive care unit in a university hospital. PATIENTS: A total of 29 consecutive immunocompetent patients with severe sepsis within 48 hrs of onset were enrolled and underwent laparotomy for a diffuse secondary peritonitis. Thirteen volunteers served as controls. MEASUREMENTS: Blood and peritoneal fluid recovered during laparotomy were analyzed and compared for 1) soluble TNF-alpha, soluble L-selectin, and type I and II TNF-alpha receptor levels; 2) PMN membrane TNF-alpha, membrane L-selectin, and TACE expression (flow cytometry); and 3) TNF-alpha production by cultured PMN. Correlations between these forms of PMN-derived TNF-alpha and the severity of the peritonitis and patient's outcome were investigated. MAIN RESULTS: Elevated soluble TNF-alpha levels in both plasma and peritoneal fluid from the patients were found, together with decreased expression of membrane TNF-alpha and TACE up-regulation at the PMN surface. Soluble L-selectin and type I and II TNF receptors were highly released, suggesting also the role of TACE. In contrast, the capacity of both blood and peritoneal PMN to synthesize TNF-alpha in vitro, in optimal conditions of stimulation (lipopolysaccharide + interferon-gamma), was impaired as compared with controls' blood PMN. Regulation of PMN-derived TNF-alpha was similar in the two compartments, but responses were more pronounced in the peritoneum. TACE up-regulation at the surface of blood-derived PMN correlated with the Sequential Organ Failure Assessment score and vital outcome. CONCLUSION: These human data demonstrate that mTACE is up-regulated at the PMN surface during severe peritonitis. This finding could be related to a paracrine regulatory loop involving some TACE substrates such as TNF-alpha, L-selectin, and TNF receptors.     

Quantitative ultrasonic tissue characterization as a new tool for continuous monitoring of chronic liver remodelling in mice.

BACKGROUND/AIM: Recognition of the limitations of liver biopsies has led to the need for non-invasive tests to assess liver fibrosis from intensity and kinetic point of views. The aim of the present study was to evaluate non-invasive ultrasonic tissue characterization for the continuous monitoring of this process in mice. METHODS: Twelve-week-old male and female C57Bl6/J mice were submitted to repetitive carbon-tetrachloride (CCl4) intraperitoneal injections during 8 weeks or analysed 28 days after common bile duct ligation (BDL). The extent and kinetic of the disease progression were followed by the measurement of ultrasound backscatter intensity. This was compared with histological and blood parameter analysis. RESULTS: CCl4 induced a progressive increase in in vivo liver tissue backscatter intensity in both males and females. This increase was mainly correlated with interstitial fibrosis and, to a lower extent, with nuclear surface of the hepatocytes. A similar result was found after BDL. CONCLUSIONS: These data demonstrate for the first time in a systematic study that ultrasound tissue characterization can be used as a reliable tool to follow liver remodelling in mice continuously.     

A new vascular sealant (Sealgel) to achieve rapid hemostasis after percutaneous angioplasty in anticoagulated patients: clinical feasibility and preliminary results

The aim of this study was to assess the feasibility of a new vascular sealant (Sealgel) to provide rapid hemostasis in anticoagulated patients after percutaneous transluminal angioplasty (PTA). Sealgel was designed with ancrod (10 mg) and tranexamic acid (80 mg) dissolved in a hyaluronic acid gel (3 ml). Fifty anticoagulated patients (heparin, aspirin, ticlopidin) who underwent PTA of coronary artery were enrolled in the study. Sealgel (3 ml) was delivered under manual compression through a 9-F cannula at the arterial puncture site after the introducer sheath removal at the end of PTA procedure. Hemostasis time as well as complications were recorded. Sealgel was successfully delivered in 98 % of patients. Hemostasis occurred within 15 mn of manual compression in 82 % of patients, within 25 mn in 98 %, and failed in 1 patient (2 %). Hematoma (6-cm diameter) was observed in 1 patient and late bleeding in another one. There were no clinical signs of embolism, inflammatory swelling, local infection, vascular fistula, or pseudoaneurysm. No surgery or blood transfusion was required. Sealgel application after PTA in anticoagulated patient is feasible and secure. Preliminary results suggest that the Sealgel brought about rapid hemostasis; however further studies are needed to determine its clinical efficacy. Received: 17 March 2000 Revised: 20 July 2000 Accepted: 26 July 2000     

The neuroanatomy of Eml1 knockout mice,a model of subcortical heterotopia

The cerebral cortex is a highly organized structure responsible for advanced cognitive functions. Its development relies on a series of steps including neural progenitor cell proliferation, neuronal migration, axonal outgrowth and brain wiring. Disruption of these steps leads to cortical malformations, often associated with intellectual disability and epilepsy. We have generated a new resource to shed further light on subcortical heterotopia, a malformation characterized by abnormal neuronal position. We describe here the generation and characterization of a knockout (KO) mouse model for Eml1, a microtubule‐associated protein showing mutations in human ribbon‐like subcortical heterotopia. As previously reported for a spontaneous mouse mutant showing a mutation in Eml1, we observe severe cortical heterotopia in the KO. We also observe abnormal progenitor cells in early corticogenesis, likely to be the origin of the defects. EML1 KO mice on the C57BL/6N genetic background also appear to present a wider phenotype than the original mouse mutant, showing additional brain anomalies, such as corpus callosum abnormalities. We compare the anatomy of male and female mice and also study heterozygote animals. This new resource will help unravel roles for Eml1 in brain development and tissue architecture, as well as the mechanisms leading to severe subcortical heterotopia.     

Effect of Cleome arabica Leaf Extract on Rat Paw Edema and Human Neutrophil Migration

The anti-inflammatory activity of Cleome arabica leaf extract was studied in vivo and in vitro. Firstly, the extract was examined for its anti-inflammatory activity using carrageenan-induced rat paw edema as a model of acute inflammation. A subplantar injection of 0.1 ml of carrageenan 1% induced a progressive swelling of the rat paw in all time points, that reached a maximal volume in placebo group within 5 h. Results showed that pre-treatment of rats by Cleome arabica leaf extract, 1 h prior the injection of the phlogogenic agent, prevented the increase of the edema in dose-dependent manner with an ED 50 of 231 mg/kg, body weight. The extract doses 100, 200 and 300 mg/kg, reduced edema to 65.54 ± 5.2%, 57.86 ± 8%, and 41.54 ± 3.6%, respectively, 5 h after the carrageenan injection. Secondly, we have examined the effect of Cleome arabica leaf extract on human neutrophil migration induced by fMLP (10 -7 M), using 48-well chemotaxis chamber. Results showed that the extract inhibited neutrophil chemotaxis significantly (p < 0.01) and in a dose-dependent manner. Neutrophil migration was reduced to 16.71 ± 4.6% in presence of 50µg/ml of Cleome arabica leaf extract. It appears that the antiinflammatory activity of Cleome arabica leaf extract, observed in vivo as well as in vitro, could be due to its high flavonoid content (19%). These results may contribute to explain the use of this plant in folk medicine.     

Ethanol-induced inhibition of cytokine release and protein degranulation in human neutrophils

Ethanol impairs immune responses in humans and animal models, in vivo and in vitro. In particular, ethanol inhibits some key functions of human polymorphonuclear neutrophils (PMN). We investigated the impact of ethanol on cytokine production by highly purified PMN. In a time- and concentration-dependent manner, ethanol inhibited the production of interleukin (IL)-8 protein and mRNA and also hindered tumor necrosis factor alpha (TNF-alpha) release by modulating the expression of the TNF-alpha-converting enzyme involved in TNF-alpha shedding. This disruption of PMN cytokine release by ethanol may contribute to the increased risk of infection in alcoholic patients. Degranulation of hepatocyte growth factor (HGF) was also impaired by a clinically relevant ethanol concentration (0.8%), an action that may delay the repair of alcoholic liver damage. These findings suggest that ethanol may modulate three major cytokines involved in alcoholic liver diseases, IL-8, TNF-alpha, and HGF, via three different mechanisms.     

Mixing and flow-induced nanoprecipitation for morphology control of silk fibroin self-assembly

Tuning silk fibroin nanoparticle morphology using nanoprecipitation for bottom-up manufacture is an unexplored field that has the potential to improve particle performance characteristics. The aim of this work was to use both semi-batch bulk mixing and micro-mixing to modulate silk nanoparticle morphology by controlling the supersaturation and shear rate during nanoprecipitation. At flow rates where the shear rate was below the critical shear rate for silk, increasing the concentration of silk in both bulk and micro-mixing processes resulted in particle populations of increased sphericity, lower size, and lower polydispersity index. At high flow rates, where the critical shear rate was exceeded, the increased supersaturation with increasing concentration was counteracted by increased rates of shear-induced assembly. The morphology could be tuned from rod-like to spherical assemblies by increasing supersaturation of the high-shear micro-mixing process, thereby supporting a role for fast mixing in the production of narrow-polydispersity silk nanoparticles. This work provides new insight into the effects of shear during nanoprecipitation and provides a framework for scalable manufacture of spherical and rod-like silk nanoparticles.

Tuning silk fibroin nanoparticle morphology using nanoprecipitation for bottom-up manufacture is an unexplored field that has the potential to improve particle performance characteristics.     

Anti-inflammatory effect of rutin on rat paw oedema, and on neutrophils chemotaxis and degranulation

BACKGROUND: Rutin, a natural flavone derivative, is known for its pharmacological properties. We have previously reported that this flavonol exerted a potent inhibitory effect on respiratory burst of fMet-Leu-Phe-stimulated neutrophils, as well as on phosphoinositide 3-kinase gamma activity in a cell free system. In the present study, the anti-inflammatory effect of rutin was investigated in vivo and in vitro. METHODS: rutin or aspirin (100 mg/kg, body weight) were given orally to rats 1 hour before paw oedema induction, using lambda-carrageenan 1%. The rat paw volume was measured by mean of plethysmometer, initially and during 6 hours. The chemotaxis of neutrophils towards 10(-7) M fMet-Leu-Phe was performed using 48-well chemotaxis chamber. Neutrophils that migrated through 5 microm pore size polycarbonate filter, in presence or in absence of rutin, were counted microscopically. Elastase exocytosis of either phorbol 12-myristate 13-acetate or fMet-Leu-Phe/cytochalasin B-stimulated neutrophils was assessed in absence or in presence of rutin using the synthetic substrate N-Suc-Ala-Ala-Ala-p-nitroanilide. The absorbance of released p-nitroaniline was measured at 405 nm using microplate reader. RESULTS: The maximal swelling in placebo group was observed at 5 hours, after lambda-carrageenan injection. Oral administration of rutin reduced rat paw swelling starting 2 hours after lambda-carrageenan injection. Rutin reduced significantly (p < 0.05) and in a dose-dependant manner the polymorphonuclear neutrophils chemotaxis to fMet-Leu-Phe. Furthermore, elastase exocytosis, induced by both stimuli, was partially inhibited by rutin up to 25 microM. CONCLUSION: The present study revealed that rutin possesses anti-inflammatory properties.     

The Effect of Arch Drop on Tibial Rotation and Tibiofemoral Contact Stress in Postpartum Women

Background

Women are at greater risk for knee osteoarthritis and numerous other lower limb musculoskeletal disorders. Arch drop during pregnancy and the resultant excessive pronation of the feet may alter loading patterns and contribute to the greater prevalence of knee osteoarthritis in women.