Modélisation des conditions d’environnement des bocaux de culture in vitro : bocaux avec agar et vitroplants

La présente étude traite de la modélisation des conditions des plantes en culture in vitro. Lorsque des vitroplants sont introduits dans les bocaux,l'humidité de l'air intérieur varie en fonction de leur stade de développementet ce en accord avec les courbes expérimentales. Les variations diurnes du déficit de pression de vapeur (DPV) présentent un maximum pendant laphotopériode et un minimum pendant la nyctipériode. Par ailleurs, grâce à la prise en compte des réservoirs de la plante, le modèle permet de décrire la déshydratation et la réhydratation des tissus, ce qui est potentiellement d'un intérêt pratique. Au cours du cycle diurne, la teneur en eau relative varie entre 75 et 90 %. Les flux d'eau dans la plante concordent bien avec les variations de la teneur en eau du réservoir plante et caractérisent bien les deux types de régimes de circulation de l'eau dans la plante : le régime de flux conservatif et le régime de flux non conservatif.Mots-clés : Modélisation, culture in vitro, humidité de l'air intérieur, réservoir-plante, déshydratation, réhydratatio

Modeling the microclimate inside a vessel in in vitro culture : vessel with agar

Numerical simulations show that variations in vessel internal humidity was sensitive to transfer coefficient, climatic conditions within the growth chamber, evaporation and condensation of water vapor on the walls of the vessel. The variations in water vapor pressure deficits (VPD) (low during the nyctiperiod and high during the photoperiod) were well explained by a free convection model, which took into account temperature differences. Finally, the results show the necessity to construct containers with variable openings and growth chambers in which bioclimatic conditions can be controlled.Les simulations numériques révèlent que les variations de l\'humidité interne ont été sensibles au coefficient d\'échange de vapeur d\'eau, aux conditions climatiques de la chambre de culture et aux phénomènes d\'évaporation et de condensation de vapeur d\'eau sur les parois des bocaux. Par ailleurs, il a été établi que le «créneau» de déficit de pression de vapeur (DPV) de l\'air intérieur (palier de DPV faible en nyctipériode et palier de DPV élevé en photopériode) a été bien imité en mode convectif libre qui tient compte des écarts de températures. Ainsi, ces résultats montrent la nécessité de construire des récipients à ouverture variable et des chambres de culture dans lesquelles les facteurs bioclimatiques des plantes peuvent être maîtrisés. Keywords: Agar, in vitro culture, microclimate, modeling, transfer coefficient./Agar, culture in vitro, microclimat, modélisation, coefficient d\'échange.Sciences & Nature Vol. 4 (1) 2007: pp. 75-8

Cabergoline treatment at dry-off facilitated the remodelling and the lactoferrin immunoprotection of the mammary tissue in dairy cows

ObjectivesIn ruminants, the early phase of drying-off is a period of intense mammary gland involution that is due, in part, to dramatic decline prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is also directly related to the risk of new intramammary infections. Thus, strategies to hasten involution following dry-off could have implications in preventing mastitis and optimizing mammary tissue regenerative processes.Materials and methodsTo assess the effect of prolactin inhibition by cabergoline on mammary gland involution, 14 Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) or placebo (n=7) within 4 hours after the last milking before the drying off at the day of drying-off (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for lactoferrin and zymography analyses to detect the activity of enzymes such as MMP, matrix metalloproteinases involved in the remodelling of mammary tissue during involution. Mammary epithelial cells (MEC) were also purified from mammary secretions after centrifugation andimmunocytochemical binding in order to evaluate the MEC exfoliation. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for lactoferrin immunochemistry and zymography analyses.ResultsThe activity of MMP9 increased after drying-off in mammary secretions (P < 0.001). Cabergoline increased the activity of MMP9 (1.7 fold, P < 0.05) in mammary secretions and MMP-2 in mammary tissue after drying-off (1.4 fold, P ≤ 0.01). MEC concentration progressively increased in mammary secretions after drying-off (P < 0.01). Cabergoline induced an increase in MEC concentration (P =0.04). Lactoferrin content progressively increased in mammary secretions during involution. The rise of lactoferrin content in mammary secretions was significant starting at D4 in the cabergoline treated cows (P ≤0.05) whereas it only happened at D8 in controls (P < 0.05). Overall, cabergoline treatment increased lactoferrin content of mammary secretions (P = 0.10). The total lactoferrin immunostaining in the mammary tissue increased after drying-off (P < 0.05). Compared with during lactation, this increase was observed at D1 and D8, respectively for cabergoline treated cows and control cows (P <0.05).ConclusionsOur results indicate that cabergoline treatment was efficient to enhance the extracellular matrix mammary remodeling, and the MEC exfoliation from the mammary epithelium and also hasten the udder immunoprotection by lactoferrin and therefore facilitates the drying-off

A case of wound dual infection with Pasteurella dagmatis and Pasteurella Canis resulting from a dog bite - limitations of Vitek-2 system in exact identification of Pasteurella species

<p>Abstract</p> <p>Background</p> <p><it>Pasteurella </it>species, widely known as indigenous orgganisms in the oral and gastrointestinal floras of many wild and domestic animals, are important pathogens in both animals and humans. Human infections due to <it>Pasteurella </it>species are in most cases associated with infected injuries following animal bites. We encountered a rare case of dual infections caused by different two <it>Pasteurella </it>species occurred in a previously healthy 25-year-old female sustaining injury by a dog-bite.</p> <p>Methodology</p> <p>Exudates from the open wound of her dog-bite site, together with the saliva of the dog were submitted for bacteriological examination. Predominantly appearing grayish-white smooth colonies with almost the same colonial properties but slightly different glistening grown on chocolate and sheep blood agar plates were characterized morphologically by Gram's stain, biochemically by automated instrument using Vitek 2 system using GN cards together with commercially available kit system, ID-Test HN-20 rapid panels, and genetically by sequencing the 16S rRNA genes of the organism using a Taq DyeDeoxy Terminator Cycle Sequencing and a model 3100 DNA sequencer instrument.</p> <p>Results</p> <p>The causative isolates from the dog-bite site were finally identified as <it>P</it>. <it>canis </it>and <it>P</it>. <it>dagmatis </it>from the findings of the morphological, cultural, and biochemical properties together with the comparative sequences of the 16S rRNA genes. Both the isolates were highly susceptible to many antibiotics and the patient was successfully treated with the administration of so-called the first generation cephalosporin, cefazolin followed by so-called the third generation cephalosporin, cefcapene pivoxil. The isolate from the dog was subsequently identified as <it>P</it>. <it>canis</it>, the same species as the isolate from the patient.</p> <p>Conclusions</p> <p>To the best of our knowledge, this was the second report of a dual infection with <it>Pasteurella </it>species consisting of <it>P</it>. <it>dagmatis </it>and <it>P. canis </it>resulting from a dog-bite, followed by the first report of dual infections due to <it>P</it>. <it>dagmatis </it>and <it>P. multocida </it>in 1988. Our isolate finally identified as <it>P</it>. <it>dagmatis </it>was misidentified as <it>P</it>. <it>pneumotripica by </it>means of the Vitek 2 system. The species name "<it>P</it>. <it>dagmatis" </it>was not included in the database of the system. It is also important for routine clinical microbiology laboratories to know the limitation of the automated Vitek 2 system for the accurate identification of <it>Pasteurella </it>species especially <it>P</it>. <it>dagmatis</it>. It should be emphasized that there still exists much room for improvement in Vitek 2 system. Significant improvement of Vitek 2 system especially in the identification of <it>Pasteurella </it>species is urgently desired.</p

Cabergoline treatment at dry-off accelerated mammary involution as indicated by mammary secretion composition changes in dairy cows

In ruminants, the early phase of drying-off is a period of mammary gland involution that is marked by the cessation of prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is directly related to the risk of new intramammary infections.ObjectivesOur aim was to assess the effect of PRL inhibition by cabergoline on the speed of the mammary gland involution, through analysis of the changes of mammary secretion composition.Materials and methodsFourteen Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) (Velactis ®, Ceva Sante Animale) or placebo (n=7) at the first day of dryingoff (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for milk fat, lactose, true protein, alpha-lactalbumin and SCC analysis. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for RNA extraction and RT-PCR analyses.ResultsAs expected, SCC progressively increased whereas lactose content decreased in mammary secretions after drying-off (P < 0.001). The increase in SCC was 2.4 fold higher in cabergoline treated cows than in control cows (P < 0.01). The decrease of lactose content in mammary secretions progressively decreased during involution and was associated with paralleled change in GLUT-1 mRNA level coding the main glucose transporter in the udder. These decreases were faster in cabergoline treated cows compared to controls with lower lactose content in cabergoline treated cows already by D1 than in controls (P < 0.05) and significant decrease in GLUT-1 mRNA levels at D1 and D8 respectively for cabergoline and control treatments compared to D-6 (P ≤ 0.05). Cabergoline treatment tended to increase fat content at D3 after drying-off (P < 0.10). No significant effects of cabergoline treatment were observed both in true protein and in alpha-lactalbumin contents in mammary secretions or in alphalactalbumin and kappa-casein mRNA levels in mammary tissues.ConclusionsThe changes in lactose, SCC and fat in mammary secretions and GLUT-1 mRNA level in the udder, indicate that cabergoline treatment was efficient to hasten the mammary gland involution without affecting milk protein synthesis in the mammary tissue. Cabergoline could facilitate dairy management at the time of dry-off

Mass Transfer by Stellar Wind

I review the process of mass transfer in a binary system through a stellar wind, with an emphasis on systems containing a red giant. I show how wind accretion in a binary system is different from the usually assumed Bondi-Hoyle approximation, first as far as the flow's structure is concerned, but most importantly, also for the mass accretion and specific angular momentum loss. This has important implications on the evolution of the orbital parameters. I also discuss the impact of wind accretion, on the chemical pollution and change in spin of the accreting star. The last section deals with observations and covers systems that most likely went through wind mass transfer: barium and related stars, symbiotic stars and central stars of planetary nebulae (CSPN). The most recent observations of cool CSPN progenitors of barium stars, as well as of carbon-rich post-common envelope systems, are providing unique constraints on the mass transfer processes.Comment: Chapter 7, in Ecology of Blue Straggler Stars, H.M.J. Boffin, G. Carraro & G. Beccari (Eds), Astrophysics and Space Science Library, Springe

Clinical significance of VEGF-A, -C and -D expression in esophageal malignancies

Vascular endothelial growth factors ( VEGF)- A, - C and - D are members of the proangiogenic VEGF family of glycoproteins. VEGF-A is known to be the most important angiogenic factor under physiological and pathological conditions, while VEGF-C and VEGF-D are implicated in the development and sprouting of lymphatic vessels, so called lymphangiogenesis. Local tumor progression, lymph node metastases and hematogenous tumor spread are important prognostic factors for esophageal carcinoma ( EC), one of the most lethal malignancies throughout the world. We found solid evidence in the literature that VEGF expression contributes to tumor angiogenesis, tumor progression and lymph node metastasis in esophageal squamous cell carcinoma ( SCC), and many authors could show a prognostic value for VEGF-assessment. In adenocarcinoma (AC) of the esophagus angiogenic properties are acquired in early stages, particularly in precancerous lesions like Barrett's dysplasia. However, VEGF expression fails to give prognostic information in AC of the esophagus. VEGF-C and VEGF-D were detected in SCC and dysplastic lesions, but not in normal mucosa of the esophagus. VEGF-C expression might be associated with lymphatic tumor invasion, lymph node metastases and advanced disease in esophageal SCC and AC. Therapeutic interference with VEGF signaling may prove to be a promising way of anti-angiogenic co-treatment in esophageal carcinoma. However, concrete clinical data are still pending

Eosinophilic myocarditis mimicking acute coronary syndrome secondary to idiopathic hypereosinophilic syndrome: a case report

<p>Abstract</p> <p>Introduction</p> <p>Eosinophilic myocarditis is a rare form of myocarditis. It is characterized pathologically by diffuse or focal myocardial inflammation with eosinophilic infiltration, often in association with peripheral blood eosinophilia. We report a case of eosinophilic myocarditis secondary to hypereosinophilic syndrome.</p> <p>Case presentation</p> <p>A 74-year-old Caucasian woman with a history of asthma, paroxysmal atrial fibrillation, stroke and coronary artery disease presented to the emergency department of our hospital with chest pain. Evaluations revealed that she had peripheral blood eosinophilia and elevated cardiac enzymes. Electrocardiographic findings were nonspecific. Her electrocardiographic finding and elevated cardiac enzymes pointed to a non-ST-elevated myocardial infarction. Echocardiogram showed a severe decrease in the left ventricular systolic function. Coronary angiogram showed nonobstructive coronary artery disease. She then underwent cardiac magnetic resonance imaging, which showed neither infiltrative myocardial diseases nor any evidence of infarction. This was followed by an endomyocardial biopsy which was consistent with eosinophilic myocarditis. Hematologic workup regarding her eosinophilia was consistent with hypereosinophilic syndrome. After being started on steroid therapy, her peripheral eosinophilia resolved and her symptoms improved. Her left ventricular ejection fraction, however, did not improve.</p> <p>Conclusion</p> <p>Eosinophilic myocarditis can present like an acute myocardial infarction and should be considered in the differential diagnosis of acute coronary syndrome in patients with a history of allergy, asthma or acute reduction of the left ventricular function with or without peripheral eosinophilia.</p

Secondary metabolites of the sponge-derived fungus Acremonium persicinum

This study reports the isolation and characterization of six new acremine metabolites, 5-chloroacremine A (4), 5-chloroacremine H (5), and acremines 0 (6), P (7), Q(8), and R (9), together with the known acremines A (1), F (2), and N (3) from the fungus Acremonium persicinum cultured from the marine sponge Anomoianthella rubra. The relative configuration of acremine F (2) was determined by analyses of proton coupling constant values and NOESY data, and the absolute configuration confirmed as (IS, 4S, 6R) by X-ray crystallographic analysis of the borate ester derivative 15. Acremines O, P, and R were each shown to be of 8R configuration by H-1 NMR analyses of MPA esters. The relative configurations suggested for acremines P and Q were each deduced by molecular modeling together with NOESY and coupling constant data. The (3)J(H-C) values in acremine P were measured using the pulse sequence EXSIDE, and the observed (3)J(H8-C4) of 5.4 Hz and small (3)J(H-C) values