VIRULENCE LEVELS OF BIOFILM-GROWN LISTERIA MONOCYTOGENES LO28 ARE LOWER THAN THOSE OF PLANKTONIC CELLS IN AN ORAL INOCULATION TEST ON MICE

The aim of this study was to produce Listeria monocytogenes biofilms suitable for virulence assays and to determine whether the released bacteria had the same virulence potential as their planktonic counterparts. Biofilms of Listeria monocytogenes LO28 strain, with or without Sphingomonas paucimobilis CCL10 strain, containing up to 7 log₁₀ cfu/cm² were produced in polypropylene syringes. The virulence of strain LO28 was analyzed in mice after intravenous, subcutaneous and oral inoculation. Its virulence level in binary cultures was not significantly different from that of monocultures. L. monocytogenes LO28 virulence in biofilms was lower than that of their planktonic counterparts after oral inoculation. Our results suggest that biofilms pose no greater health risk to the consumer than planktonic bacteria.     

Taenia crassiceps invasive cysticercosis: a new human pathogen in acquired immunodeficiency syndrome?

High-energy electrons bombarded on materials can induce radioactivity by either directly knocking out neutrons or by first converting a fraction of the electron kinetic energy into electromagnetic energy, with subsequent neutron emission induced by the photons produced. The purpose of this paper was to develop a calculation method for estimating neutron emission and radionuclide production by high-energy (15-25 MeV) electrons directly interacting with a nucleus. The reaction (e,n) is considered using the method of virtual photons. The cross section for electron bombardment of lead, tantalum, rhenium, and tungsten targets is calculated. The electron cross sections are roughly 100 times less than the corresponding photon cross sections. The cross section increases monotonically with incident energy. A traveling wave linear accelerator was used for a qualitative test of the magnitude and energy dependence of the calculated cross sections. Tantalum was bombarded with electrons and the resultant emission of neutrons was inferred from the induced activation of 180Ta. The energy dependence and magnitude of the calculated electron cross sections agree with experiment within experimental uncertainties. It is concluded that accurate estimates of electron activation via the direct process is possible.     

Immediate and 6-month results of balloon angioplasty in the treatment of intra-stent restenosis in symptomatic patients

Initial anesthesic-induced hypothermia results largely from core-to-peripheral redistribution of heat. Administration of transdermal nitroglycerin induces vasodilation. Such vasodilation, induced well before induction of anesthesia, might redistribute heat to peripheral tissues. Minimal redistribution hypothermia might accompany subsequent induction of anesthesia. We studied 32 patients undergoing gastrointestinal surgery. Thirty minutes before induction of anesthesia, they were randomly assigned to: 1. transdermal nitroglycerin 10 mg; 2. transdermal nitroglycerin 5 mg; and, 3. control. Core temperature during the first hour of anesthesia decreased significantly more in the control patients than in those given either dose of nitroglycerin. Vasodilation induced by transdermal nitroglycerin before induction of anesthesia significantly decreased subsequent redistribution hypothermia. Drug-induced modulation of vascular tone thus produces clinically important alterations in intraoperative core temperature.     

Coronary involvement in systemic lupus erythematosus

BACKGROUND: Coronary artery disease is an uncommon event in lupus erythematosus. The mechanisms responsible for coronary occlusion are probably complex and intermixed. We report three patients with lupus erythematosus and antiphospholipid antibodies who had coronary artery disease diagnosed with coronary angiogram. OBSERVATION: Coronary artery disease occurred in three young patients aged from 21 to 35 years 3 to 11 years after the onset of lupus. They all had antiphospholipid antibodies. They had been treated with corticosteroids for 6 to 36 months. Two of them were smokers. Angiograms showed coronary occlusion two patients while the third one had probable myocardial microvasculopathy. The lupus was quiescent in all cases when coronary artery disease occurred. DISCUSSION: Antiphospholipid antibodies associated with smoking may be involved in the pathogenesis of coronary artery disease in these 3 patients.     

AN OPTICAL METHOD TO STUDY THE KINETICS OF CLEANING MILK DEPOSITS BY SODIUM HYDROXIDE

An optical sensor was devised to observe cleaning kinetics of heat exchange surfaces fouled by milk and to study the influence of some parameters on them. The sensor works by sensing the attenuation of incident light by the suspension of deposits which are removed by the cleaning solution. The cleaning is carried out without recycling the cleaning solution. The on-line collected numerical data are converted into concentration values by the use of an empirical correlation based on samples of freeze dried deposits diluted with soda solutions. The cleaning kinetics and the weight of removed fouled material are computed for each experiment by integrating the concentration versus time curve. Over 20 experiments, carried out on a plate milk pasteurizer have established the validity of the method. The kinetics are interpreted as initially zero order, but first order at the end of the process.     

ASSESSING AGREEMENT BETWEEN HUMAN AND MACHINE CLUSTERINGS OF IMAGE DATABASES

There is currently much interest in the organization and content-based querying image databases. The usual hypothesis is that image similarity can be characterized by low-level features, without further abstraction. This assumes that agreement between machine and human measures of similarity is sufficient for the database to be useful. To assess this assumption, we develop measures of the agreement between partitionings of an image set, showing that chance agreements must be considered. These measures are used to assess the agreement between human subjects and several machine clustering techniques on an image set. The results can be used to select and refine distance measures for querying and organizing image databases.     

Human duodenal proteome modulations by glutamine and antioxidants

Purpose : Glutamine (Gln) has protective, anti‐inflammatory effects in animal models and humans. Antioxidant nutrients may exert synergistic effects on intestinal functions. Therefore, these combined nutrients may have a therapeutic potential during intestinal inflammation. This study was designed to investigate in humans the effects of a supplement composed of Gln and high‐dosed antioxidant micronutrients compared to isomolar Gln only, on duodenal proteome. Experimental design : Enteral perfusion of Gln (0.8 mmol . kg^?1. h^?1) or supplement was performed in two groups of six healthy volunteers during 5 h before taking endoscopic duodenal biopsies. Protein expression was analyzed by 2‐DE and the relevant proteins identified by MS/MS. Results : About 1500 protein spots were revealed in both supplement and Gln conditions. Comparative proteomics analysis indicated that 11 proteins were differentially and significantly (p≤0.05) expressed in response to the supplement. These proteins were essentially implicated in metabolism pathways, e.g. fatty acid binding protein‐1 and 40S ribosomal protein SA expressions were downregulated while manganese superoxide dismutase and retinal dehydrogenase‐1 expressions were upregulated. Conclusions and clinical relevance : This study provides new information on human duodenal proteome and its nutritional modulation, and supports further clinical investigations designed to evaluate the effects of Gln plus antioxidants during intestinal inflammation and cancer.     

A study of long-term survival, functional outcome and quality of life in patients with polymyositis or dermatomyositis

There have been few studies of long-term functional outcomes and quality of life in patients with polymyositis or dermatomyositis. PATIENTS: 28 patients, 16 female and 12 male, meeting Bohan's and Peter's criteria and admitted between 1970 and 1993, were studied retrospectively; nine had polymyositis and 19 dermatomyositis (with onset during childhood in five cases); mean age was 43.5 years. METHODS: we reevaluated 18 of the 28 patients, after a mean interval of eight years; among the ten remaining patients, eight had died, one could not be traced and one declined reevaluation. Survival, muscle function, joint function, respiratory function and quality of life (AIMS 1) were determined. Factors predicting the value of these parameters were looked for. RESULTS: significant excess mortality was observed as compared with the general population in the Seine Maritime region of France. Easy fatigability and decreased exercise tolerance were found in 50% of evaluated patients; Ritchie's index was 0 in 67% of patients and between 1 and 7 in 33%; 55% of patients had dyspnea and 50% had abnormal respiratory function parameters; quality of life items were usually rated "fairly good" or "very good", except for "physical activities", which were given "poor" or "very poor" ratings by one third of patients. We found no factors associated with survival or any of the above-mentioned functional parameters, except for male gender, which predicted better muscle function. DISCUSSION: polydermatomyositis is associated with excess mortality; alterations in muscle function persist in half the cases and the ability to carry out physical activities is often reduced. The retrospective design of our study, small sample size and heterogeneity of our population precluded identification of factors predictive of survival, loss of function, or poor quality of life.     

Impedance spectroscopy study of anodic growth of thick zirconium oxide films in H2SO4, Na2SO4 and NaOH solutions

Anodic zirconium oxide films were grown potentiodynamically at a constant sweep rate up to the breakdown potential on rod electrodes made of 99.8% metallic zirconium. Different media of different pH were tested, namely 0.5 M H₂SO₄ (pH 0.3), 0.1 M Na₂SO₄ (pH 9) and 0.1 M NaOH (pH 13). By electrochemical impedance spectroscopy and scanning electron microscopy the oxide film thickness was monitored during the voltage scan. The behaviour was found to be different in the presence and absence of sulphate anions. In the presence of SO₄²⁻, the films were dense but breakdown occurred at 300–340 nm. In NaOH, two relaxations appeared above 50 V and were ascribed to a bi-layered coating structure and the maximum layer thickness was 720 nm before breakdown.     

High Velocity Oxyfuel Deposition for Low Surface Roughness PS304 Self-Lubricating Composite Coatings

Efforts were made to achieve lower (R _q < 0.1 μm) initial RMS roughnesses of PS304 coatings so that they may be considered for foil bearings operating under increasingly severe conditions that result in smaller air film thicknesses. Attainable roughness of conventional plasma-sprayed PS304 coatings has been typically R _q > 0.25 μm, as limited by porosity in the deposited coating and surface irregularities correspondingly formed upon finishing. Initial attempts at achieving dense coatings by instead using a high-velocity oxyfuel (HVOF) flame-spraying process failed due to insufficient heating and softening of the NiCr and Cr ₂ O ₃ constituents of the PS304 feed powder, which rebounded from the steel target substrate and resulted in low deposition yield. Efficient HVOF deposition by a hydrogen-fueled system was achieved using NiCr and Cr ₂ O ₃ constituent particles of reduced size that were more effectively heated. The resultant dense coatings provided roughnesses as low as R _q = 0.05 μm upon polishing. Tribological performance of these HVOF coatings was evaluated against Inconel X-750 in thrust-washer tests at a sliding speed of 5.4 m/s, with contact pressures of 20 and 40 kPa, and ambient or 500°C temperatures. The wear and friction performances in direct sliding contact, as would exist upon loss of separating air-bearing film, of the PS304 coatings produced by HVOF are found to be similar to those deposited by the plasma spray process.