Experimental Bacterial Endocarditis After Dental Extractions in Rats with Periodontitis

The development of bacterial endocarditis was analyzed after dental extractions in rats with or without periodontal disease. Periodontal disease was produced in rats by tying silk ligatures around the two maxillary first molars and placing the animals on a high sucrose diet for 14 weeks. Sterile aortic valve vegetations were produced by means of a transaortic catheter, and 24 hr later the maxillary first molars were extracted. The animals were killed 72 hr after the extractions. In rats with periodontal disease, extractions resulted in a 48% (14 of 29) incidence of bacterial endocarditis, most cases of which were due to Streptococcus spp. (one was caused by Staphylococcus aureus). In contrast, when the teeth with a healthy periodontium were extracted, only 6% (one of 15) of the rats developed endocarditis. When catheters were placed in anim, tis with periodontal disease but no extractions were performed, no endocarditis occurre

β-Lactam Resistance Mechanisms of Methicillin-Resistant Staphylococcus aureus

In vitro and in vivo activity of amoxicillin and penicillin G alone or combined with a penicillinase inhibitor (clavulanate) were tested against five isogenic pairs of methicillin-resistant Staphylococcus aureus (MRSA) producing or not producing penicillinase. Loss of the penicillinase plasmid caused an eight times or greater reduction in the MICs of amoxicillin and penicillin G (from ⩾64 to 8 µg/ml), but not of the penicillinase-resistant drugs methicillin and cloxacillin (⩾64 µg/ml). This difference in antibacterial effectiveness correlated with a more than 10 times greater penicillin-binding protein 2a affinity of amoxicillin and penicillin G than of methicillin and a ⩾90% successful amoxicillin treatment of experimental endocarditis due to penicillinasenegative MRSA compared with cloxacillin, which was totally ineffective (P < .001). Amoxicillin was also effective against penicillinase-producing parent MRSA, provided it was combined with clavulanate. Penicillinase-sensitive β-lactam antibiotics plus penicillinase inhibitors might offer a rational alternative treatment for MRSA infection

Trade-off between constitutive and inducible resistance against herbivores is only partially explained by gene expression and glucosinolate production

The observed partial correlation between herbivore resistance, defensive metabolites accumulation, and gene expression suggests a complex network of gene interactions governing the postulated trade-off between constitutive defences and their inducibilit

Antibiotic Treatment of Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus epidermidis

The natural history and treatment of experimental endocarditis due to heterogeneous and homogeneous methicillin-resistant Staphylococcus epidermidis was investigated. Amoxicillin/clavulanate or vancomycin were administered for 3 days via a computerized pump to mimic human drug kinetics in animals. After challenge with the minimum inoculum producing 90% of infections (ID90) , bacteria in the vegetations grew logarithmically for 16 h. Then, bacterial densities stabilized (at ∼108 cfu/g) and growth rates sharply declined. Both regimens cured ⩾60% of endocarditis (due to heterogeneous or homogeneous bacteria) when started 12-16 h after infection, although the bacterial densities in the vegetations had increased by 20 times in between. In contrast, treatment started after 24 h failed in most animals, while bacterial densities had not increased any more. Thus, while both regimens were equivalent, the therapeutic outcome was best predicted by growth rates in the vegetations, not by bacterial densities. These observations highlight the importance of phenotypic tolerance developing in viv

Importance of Genotypic and Phenotypic Tolerance in the Treatment of Experimental Endocarditis Due to Streptococcus gordonii

Genotypic and phenotypic tolerance was studied in penicillin treatment of experimental endocarditis due to nontolerant and tolerant Streptococcus gordonii and to their backcross transformants. The organisms were matched for in vitro and in vivo growth rates. Rats with aortic endocarditis were treated for 3 or 5 days, starting 12, 24, or 48 h after inoculation. When started at 12 h, during fast intravegetation growth, 3 days of treatment cured 80% of the nontolerant parent compared with <30% of the tolerant derivative (P < .005). When started at 24 or 48 h and if intravegetation growth had reached a plateau, 3 days of treatment failed against both bacteria. However, a significant difference between the 2 organisms was restored when treatment was extended to 5 days. Thus, genotypic tolerance conferred a survival advantage in both fast- and slow-growing bacteria, demonstrating that the in vitro-defined tolerant phenotype also carried the risk of treatment failure in viv

Ischemic Colitis: Clinical Presentation, Localization in Relation to Risk Factors, and Long-Term Results

Background: Ischemic colitis is commonly thought to occur most often in the left hemicolon close to the splenic flexure owing to insufficient blood supply near Griffith's point. This study investigates the colorectal localization pattern, the risk factors, and the long-term outcome of histologically proven ischemic colitis. Methods: Between 1996 and 2004, a total of 49 patients with a median age of 69years (range 26-94years) with colonoscopically assessed and histologically proven ischemic colitis were identified on behalf of the pathology database. Long-term results of 43 patients were evaluated retrospectively after a median interval of 79months (range 6-163months). Results: In 27 patients (55%) more than one location was affected. We found 98 affected locations in 49 patients. The distribution of ischemic colitis in our group shows no significantly preferred location. In an exploratory analysis, the cecum, ascending colon, and right flexure were affected significantly more often if intake of a nonsteroidal antiinflammatory drug (NSAID) is documented. There was no association between the location of ischemic colitis and a history of smoking, peripheral artery occlusive disease, coronary heart disease, diabetes, or malignant tumor. Conclusions: Ischemic colitis seems not to have a predisposing site of occurrence in the colorectum, especially Griffith's point which was not afflicted significantly more often than other sites. Frequently, ischemic colitis afflicts more than one colonic location. In patients being treated with NSAIDs, ischemic colitis was observed significantly more often in the right hemicolon. Recurrence of ischemic colitis seems to be rar

Evolution of impulsivity levels in relation to early cannabis use in violent patients in the early phase of psychosis

Background Prevention of violent behaviors (VB) in the early phase of psychosis (EPP) is a real challenge. Impulsivity was shown to be strongly related to VB, and different evolutions of impulsivity were noticed along treatments. One possible variable involved in the relationship between VB and the evolution of impulsivity is cannabis use (CU). The high prevalence of CU in EPP and its relationship with VB led us to investigate: 1/the impact of CU and 2/the impact of early CU on the evolution of impulsivity levels during a 3-year program, in violent and non-violent EPP patients. Methods 178 non-violent and 62 violent patients (VPs) were followed-up over a 3 year period. Age of onset of CU was assessed at program entry and impulsivity was assessed seven times during the program. The evolution of impulsivity level during the program, as a function of the violent and non-violent groups of patients and CU precocity were analyzed with linear mixed-effects models. Results Over the treatment period, impulsivity level did not evolve as a function of the interaction between group and CU (coef. = 0.02, p = 0.425). However, when including precocity of CU, impulsivity was shown to increase significantly only in VPs who start consuming before 15 years of age (coef. = 0.06, p = 0.008). Conclusion The precocity of CU in VPs seems to be a key variable of the negative evolution of impulsivity during follow-up and should be closely monitored in EPP patients entering care since they have a higher risk of showing VB

Bactericidal/Permeability-Increasing Protein Inhibits Induction of Macrophage Nitric Oxide Production by Lipopolysaccharide

A recombinant (r) NH2-terminal fragment of bactericidal/permeability-increasing protein, rBPI23, was shown to inhibit murine macrophage nitric oxide (NO) production elicited by lipopolysaccharide (LPS) plus interferon-β (IFN-β). Normal mouse plasma amplified NO synthesis (measured as NO-2 release) at LPS concentrations of 1-10 ng/mL, and antibody to the plasma LPS-binding protein (LBP) partially inhibited N02 release in the presence of normal mouse plasma. rBPI23 (1 µg/mL) effectively inhibited LPS-dependent NO-2 release in the presence or absence of normal mouse plasma. Fifty percent inhibition of IFN-β/LPS-elicited NO-2 production or of binding of fluoresceinated LPS was obtained with ∼0.2 µg/mL rBPI23. These results provide a basis for studies of rBPI23 effects on NO synthase activity in murine models of gramnegative sepsi

Herausforderungen der Lektüre an einer Philosophischen Fakultät: unterschiedliche Ansichten von Studierenden und Lehrkräften

L\u27article s\u27intéresse aux difficultés de lecture universitaire des étudiant·e·s. Après une synthèse des rares travaux sur la question et l\u27expression de leurs liens avec ceux sur les littératies universitaires, notre contribution propose un compte rendu d\u27une étude empirique portant sur les difficultés perçues par des étudiant·e·s d\u27une faculté des Lettres de Suisse romande et par leurs enseignant·e·s. Les résultats indiquent que ces dernier·ère·s perçoivent plus de difficultés que les premier·ère·s ; que cela soit dans une évaluation globale, ou spécifique à certains aspects de la lecture. Ce grand écart, couplé à un champ d\u27étude encore étroit, nous invitent à défendre la réplication de telles études et la systématisation des définitions et méthodologies à utiliser. (DIPF/Orig.)Dieser Artikel befasst sich mit den Leseschwierigkeiten von Studierenden auf Universitätsniveau. Nach einem kurzen Überblick über die wenigen existierenden Arbeiten zu diesem Thema sowie zum Thema der universitären Literalität, präsentiert der Beitrag eine empirische Studie zu den Wahrnehmungen - der Studierenden einerseits, der Lehrpersonen andererseits - der Schwierigkeiten, die bei der Lektüre von den Texten an einer Westschweizer Philosophischen Fakultät auftreten. Die Resultate zeigen, dass die Lehrpersonen mehr und auch grössere Schwierigkeiten wahrnehmen als Studierende, und dies sowohl in allgemeinen Beurteilungen als auch in spezifischen Bereichen. Diese Unstimmigkeit sowie der Mangel an vergleichbaren Studien führen die Autorinnen und den Autor dazu, für weitere Recherchen und für eine Vereinheitlichung von Definitionen und Methoden zu plädieren. (DIPF/Orig.