[Hydatic pulmonary embolism: a rare complication of hepatic hydatid cyst]. / Embolie pulmonaire d'origine hydatique : une complication rare du kyste hydatique du foie.

Hepato-pulmonary hydatidosis is a parasitic disease common in Mediterranean countries. Hydatid pulmonary embolism is extremely rare and is due to rupture of a cardiac hydatid cyst or, more rarely, rupture of a hepatic hydatid cyst. We report three cases of hydatid pulmonary embolism secondary to rupture of a hydatid cyst into the inferior vena cava. Thoracic imaging, mainly CT angiography and MRI, was important for both the diagnosis and decisions on treatment. The prognosis of intra-arterial pulmonary hydatid cyst is poor because of the risk of acute fatal complications such as anaphylactic shock and vascular rupture and also of chronic progression to cor pulmonale and respiratory failure. The therapeutic management is difficult and often only partially effective hence the importance of focusing on preventative treatment.

Characterization of the biofouling and cleaning efficiency of nanofiltration membranes.

The nanofiltration (NF) drinking water production unit of the Mery-sur-Oise plant (Val d'Oise, France) consists of eight identical filtration trains composed of three stages positioned in steps for a production capacity of 140,000 m(3) day(-1). To gain a better understanding of the irreversible fouling of the NF membranes, spiral wound modules in operation for 8 years from each of the three stages of the plant were autopsied before and after chemical cleaning and analysis by Attenuated Total Reflection Fourier Transform Infrared spectroscopy, Inductive Coupled Plasma-Atomic Emission Spectrometry, contact angles, adenosine triphosphate (ATP) content measurements, and rheometry. The fouled membranes from the three stages had similar contact angles of approximately 60 degrees . Relative infrared signals typical of biofilms were classified in descending order from stage 1 to stage 3. The foulant matter of stages 1 and 2 contained similar but weaker ATP concentrations than stage 3. During rheometry experiments, rotation and oscillation analyses demonstrated that the biofilm of stage 3 was less viscous and less elastic than the biofilms of stages 1 and 2. After cleaning, all the parameters analyzed demonstrated a quantitative decrease in the fouling matter at the NF membrane surface, but a biofilm with intact viscoelastic properties (unchanged G' and G'' values) remained at the membrane surface for the three stages. The persistence of biofilm material with intact mechanical properties at the NF membrane surface after chemical cleaning may result in permanent permeability decreases.

Rheology of biofilms formed at the surface of NF membranes in a drinking water production unit.

In this study, the mechanical properties of biofilms formed at the surface of nano-filtration (NF) membranes from a drinking water plant were analysed. Confocal laser scanning microscopy observations revealed that the NF biofilms formed a dense and heterogeneous structure at the membrane surface, with a mean thickness of 32.5 +/- 17.7 mum. The biofilms were scraped from the membrane surface and analysed in rotation and oscillation experiments with a RheoStress 150 rotating disk rheometer. During rotation analyses, a viscosity decrease with speed of shearing characteristic of rheofluidification was observed (eta = 300 Pa s for ý = 0.3 s(-1)). In the oscillation analyses with a sweeping of frequency (1-100 Hz), elasticity (G') ranged from 3000 to 3500 Pa and viscosity (G'') from 800 to 1200 Pa. Creep curves obtained with an application of a shear stress of 30 Pa were viscoelastic in nature. The G(0) and eta values were, respectively, 1.4 +/- 0.3 x 10(3) Pa and 3.3 +/- 0.65 x 10(6) Pa s. The relationship between the characteristics of NF biofilms and the flow conditions encountered during NF is discussed.

Effect of chlorhexidine and benzalkonium chloride on bacterial biofilm formation.

AIM: To study the effect of antiseptics on bacterial biofilm formation. METHODS AND RESULTS: Biofilm formation and planktonic growth were tested in microtiter plates in the presence of antiseptics. For Escherichia coli G1473 in the presence of chlorhexidine or benzalkonium chloride, for Klebsiella pneumoniae CF504 in the presence of chlorhexidine and for Pseudomonas aeruginosa PAO1 in the presence of benzalkonium chloride, biofilm development and planktonic growth were affected at the same concentrations of antiseptics. For PAO1 in the presence of chlorhexidine and CF504 in the presence of benzalkonium chloride, planktonic growth was significantly inhibited by a fourfold lower antiseptic concentration than biofilm development. For Staphylococcus epidermidis CIP53124 in the presence of antiseptics at the minimal inhibitory concentration (MIC), a total inhibition of biofilm formation was observed. For Staph. epidermidis exposed to chlorhexidine at 1/2, 1/4 and 1/8 MIC, or to benzalkonium chloride at 1/8, 1/16 or 1/32 MIC, biofilm formation was increased from 11.4% to 22.5% without any significant effect onto planktonic growth. CONCLUSIONS: Chlorhexidine and benzalkonium chloride inhibited biofilm formation of different bacterial species but were able to induce biofilm development for the Staph. epidermidis CIP53124 strain at sub-MICs. SIGNIFICANCE AND IMPACT OF THE STUDY: Sublethal exposure to cationic antiseptics may contribute to the persistence of staphylococci through biofilm induction.

A large multigene family codes for the polypeptides of the crystalline trichocyst matrix in Paramecium.

The secretory granules (trichocysts) of Paramecium are characterized by a highly constrained shape that reflects the crystalline organization of their protein contents. Yet the crystalline trichocyst content is composed not of a single protein but of a family of related polypeptides that derive from a family of precursors by protein processing. In this paper we show that a multigene family, of unusually large size for a unicellular organism, codes for these proteins. The family is organized in subfamilies; each subfamily codes for proteins with different primary structures, but within the subfamilies several genes code for nearly identical proteins. For one subfamily, we have obtained direct evidence that the different members are coexpressed. The three subfamilies we have characterized are located on different macronuclear chromosomes. Typical 23-29 nucleotide Paramecium introns are found in one of the regions studied and the intron sequences are more variable than the surrounding coding sequences, providing gene-specific markers. We suggest that this multigene family may have evolved to assure a microheterogeneity of structural proteins necessary for morphogenesis of a complex secretory granule core with a constrained shape and dynamic properties: genetic analysis has shown that correct assembly of the crystalline core is necessary for trichocyst function.

Antibodies that can discriminate between dynein heavy chains and their HUV1 photoproducts.

Dyneins are multi-subunit enzymes that transduce chemical energy into the mechanical energy that makes cilia and flagella beat and moves organelles towards the minus end of microtubules. The ATPase activity is borne by heavy chains, and recent molecular analysis indicates that dynein heavy chain genes form an ancient multigene family: the similarity between the same isoform of two distantly related species is greater than that between different isoforms of the same species. We have exploited sequence identities between a Paramecium axonemal dynein heavy chain gene cloned in our laboratory and sequences of dynein heavy chains from other species to prepare antibodies against active-site peptides capable of recognizing dynein heavy chains regardless of species or isoform. One of the antibodies is perfectly specific for the larger product of V1 photolysis (HUV1) and thus incorporates a unique property of the hydrolytic ATP binding site of all known dynein heavy chains, the capacity for photocleavage in the presence of micromolar vanadate. Our characterization of these reagents suggests that they will be useful for biochemical and in situ studies of known dyneins as well as identification of potential new members of the family.