Evaluation of cross‐linked chitosan microparticles for bone regeneration

The objective of this preliminary study was to evaluate the applying of chitosan (CS)‐based microparticles (MPs) in bone regeneration in vivo. The CS MPs were fabricated using our scale‐up method, as previously described. Mesenchymal stem cells (MSC) were harvested from the femora and tibiae of Dark Agouti (DA) rats and seeded on CS MPs. An in vitro MSCs attachment experiment was conducted by trypsinizing the cells attached to the MPs at 5, 10, 20 and 30 h. Fluorescence images of MSCs attached to the MPs were taken at 24 and 48 h, using a LIVE/DEAD cell assay. The MSC/osteoblasts (OB) seeded on MPs were then cultured in vitro using osteogenic media and implanted into partial thickness bone defects in rat femurs. There were two groups of rats, including experimental animals and controls, for the in vivo studies. The experimental group were implanted with MSC‐seeded MPs and observed at 4 and 8 weeks. The control group of rats did not receive any implant material except the stainless steel plate to support the defect. Four rats per group were used for the study. The femurs were extracted at 4 and 8 weeks post‐implantation and bone formation at the defect site was analysed using radiography, microcomputed tomography (µCT) and histology. Among all groups, a significant increase in bone formation was observed in the experimental group at 8 weeks implantation. The results of this study suggested that CS MPs prove to be a successful biomaterial for bone regeneration. Copyright © 2010 John Wiley & Sons, Ltd.     

Host structural carbohydrate induces vector transmission of a bacterial plant pathogen

Many insect-borne pathogens have complex life histories because they must colonize both hosts and vectors for successful dissemination. In addition, the transition from host to vector environments may require changes in gene expression before the pathogen''s departure from the host. Xylella fastidiosa is a xylem-limited plant-pathogenic bacterium transmitted by leafhopper vectors that causes diseases in a number of economically important plants. We hypothesized that factors of host origin, such as plant structural polysaccharides, are important in regulating X. fastidiosa gene expression and mediating vector transmission of this pathogen. The addition of pectin and glucan to a simple defined medium resulted in dramatic changes in X. fastidiosa''s phenotype and gene-expression profile. Cells grown in the presence of pectin became more adhesive than in other media tested. In addition, the presence of pectin and glucan in media resulted in significant changes in the expression of several genes previously identified as important for X. fastidiosa''s pathogenicity in plants. Furthermore, vector transmission of X. fastidiosa was induced in the presence of both polysaccharides. Our data show that host structural polysaccharides mediate gene regulation in X. fastidiosa, which results in phenotypic changes required for vector transmission. A better understanding of how vector-borne pathogens transition from host to vector, and vice versa, may lead to previously undiscovered disease-control strategies.     

La colite aiguë grave: un vieux concept toujours en quête d’une définition consensuelle !

Although an important and continuous evolution of the severe acute colitis treatment, the definition of the severity of an acute colitis remained controversial. Indeed, during severe acute colitis, the criteria of severity are only well validated in the field of the inflammatory bowel diseases, especially in ulcerative colitis. In this article, we discuss the relevance of the clinical, biological, morphological and evolutive criteria in the definition of the severity of an acute colitis and then, in the therapeutic decision.     

Effect of chronic pre‐treatment with angiotensin converting enzyme inhibition on skeletal muscle mitochondrial recovery after ischemia/reperfusion

Impaired skeletal muscle energetic participates in peripheral arterial disease (PAD) patient’s morbidity and mortality. Angiotensin converting enzyme inhibition (ACEi), cornerstone for pharmacologic risk factor management in PAD patients, might also be interesting by protecting skeletal muscle energetic. We therefore determined whether chronic ACEi might reduce ischemia‐induced mitochondrial respiratory chain dysfunction in the frequent setting of hindlimb ischemia–reperfusion. Ischemic legs of rats submitted to 5 h ischemia induced by a rubber band tourniquet applied on the root of the hindlimb followed by reperfusion without (IR, n = 11) or after ACEi (n = 14; captopril 40 mg/kg per day during 28 days before surgery) were studied and compared to that of sham‐operated animals (n = 11). The effect of ACEi on the non‐ischemic contralateral leg was also determined in the ACEi group. Maximal oxidative capacities (V_max) and complexes I, II and IV activities of the mitochondrial respiratory chain of the gastrocnemius muscle were determined using glutamate–malate, succinate and TMPD–ascorbate substrates. Arterial blood pressure was significantly decreased after ACEi (124 ± 2.8 vs. 108 ± 4.19 mmHg; P = 0.01). Ischemia–reperfusion reduced V_max (4.4 ± 0.4 vs. 8.7 ± 0.5 μmol O₂/min/g dry weight, ?49%, P < 0.001), affecting mitochondrial complexes I, II and IV activities. ACEi failed to modulate ischemia‐induced dysfunction (V_max 5.1 ± 0.7 μmol O₂/min/g dry weight) or the non‐ischemic contralateral muscle respiratory rate. Ischemia–reperfusion significantly impaired the mitochondrial respiratory chain I, II and IV complexes of skeletal muscle. Pharmacologic pre‐treatment with ACEi did not prevent or increase such alterations. Further studies might be useful to improve the pharmacologic conditioning of PAD patients needing arterial revascularization.     

Late-Onset Radial Nerve Palsy Associated with Conservatively Managed Humeral Fracture. A Case Report and Suggested Classification System

Radial nerve palsy can occur with humerus fracture, either at the time of injury (primary) or during reduction (secondary). Late-onset radial nerve palsy (not immediately related to injury or reduction) has been very seldom reported in the English literature. We describe a case of late-onset radial nerve palsy, which developed 9 weeks after an attempted closed management of a midshaft humerus fracture. Exploration of the nerve was performed. The radial nerve was found to be stretched over the ends of the fracture. Open reduction and external fixation of the fracture with mobilization of the nerve from the fracture site lead to complete return of radial nerve function occurring by 3 months. We recommend exploration of cases of late-onset radial nerve palsy in contrast to primary or secondary radial nerve palsy, which can be treated conservatively. Our experience suggests that the cause of the palsy is a continuous ongoing pathology and not a single time event as in primary or secondary cases. Radial nerve palsies associated with humeral fracture should be classified as either primary (at the time of injury), secondary (at the time of reduction), or late onset (not related to either injury or reduction).     

Risk factors in enterococci isolated from foods in Morocco: Determination of antimicrobial resistance and incidence of virulence traits

A collection of enterococci isolated from meat, dairy and vegetable foods from Morocco including 23 Enterococus faecalis and 15 Enterococcus faecium isolates was studied. All isolates were sensitive to ampicillin, penicillin, and gentamicin. Many E. faecalis isolates were resistant to tetracycline (86.95%), followed by rifampicin (78.26% ciprofloxacin (60.87%), quinupristin/dalfopristin (56.52%), nitrofurantoin (43.47%), levofloxacin (39.13%), erythromycin (21.73%), streptomycin (17.39%), chloramphenicol (8.69%), vancomycin (8.69%), and teicoplanin (4.34%). E. faecium isolates showed a different antibiotic resistance profile: a high percentage were resistant to nitrofurantoin (73.33%), followed by erythromycin (66.60%), ciprofloxacin (66.66%), levofloxacin (60.00%), and rifampicin (26.66%), and only a very low percentage were resistant to tetracycline (6.66%). One isolate was resistant to vancomycin and teicoplanin. The incidence of virulence factors was much higher among E. faecalis isolates, especially for genes encoding for sex pheromones, collagen adhesin, enterococcal endocarditis antigen, and enterococcal surface protein. Isolates with multiple factors (both antibiotic resistance and virulence traits) were also more frequent among E. faecalis isolates, in which one isolate cumulated up to 15 traits. By contrast, several isolates of E. faecium had only very few unwanted traits as compared to only two isolates in E. faecalis. The high abundance of isolates carrying virulence factors and antibiotic resistance traits suggests that the sanitary quality of foods should be improved in order to decrease the incidence of enterococci.     

Preliminary experince with a combination of clomiphene and variable dosages of menopausal gonadotropins for enhanced follicular recruitment

A combination of clomiphene citrate and human menopausal gonadotropin was employed for enhanced follicular recruitment in an in vitro fertilization program. All patients received 50 mg of clomiphene and 1 ampule of human menopausal gonadotropin daily from cycle day 5 through cycle day 9. Follicular monitoring was begun on day 10 using a combination of ultrasound measurement of follicular size and number and determination of peripheral estradiol levels. Based on the size and number of follicles, the peirpheral levels of estradiol, and the rate of follicular growth and increase in estradiol, human menopausal gonadotropin was continued at a dosage of 1 to 3 ampules/day through the day of human chorionic gonadotropin administration. Human chorionic gonadotropin was administered on the evening of the day the largest follicle reached or exceeded 20 mm in mean diameter if the estradiol levels had been rapidly rising or reaching a plateau and had exceeded a minimal level of 300 pg/ml. Using this protocol, 30 of 33 patients underwent laparoscopy, 29 patients had successful oocyte recovery, and 23 patients underwent embryo replacement, with the establishment of six clinical pregnancies.     

A new patient classification for laser resurfacing and peels: predicting responses,risks, and results

Traditional classifications for skin treatment modalities are based on skin characteristics, the most important being skin color. Other factors are considered as well, such as oiliness, thickness, pathology, and sensitivity. While useful, these classifications are occasionally inadequate in predicting and explaining the outcome of some peels, dermabrasions, or laser resurfacing procedures. Why, for example, would a Korean patient with a light white skin inadvertently develop more hyperpigmentation than his darker skinned French counterpart? The new classification introduced here is based on the racial and genetic origins of patients. It suggests that racial genetic predisposition is the determining factor in human response to skin injury, including skin treatments. This classification takes into account both skin and features, rather than skin alone. It offers a new approach in evaluating patients scheduled for skin peels or laser resurfacing, in the hope of helping physicians to better predict reactions, select the appropriate type and intensity of the skin treatment and, ultimately, better control the outcome. Six categories (sub-races) are described: Nordics, Europeans, Mediterraneans, Indo-Pakistanis, Africans, and Asians. The reaction of each sub-race to peels, laser resurfacing, or dermabrasion is analyzed. The risks associated with each group are noted. This new classification provides physicians with a practical way to evaluate patients prior to treatment, with a view to determining each patient's suitability, postoperative reaction, the likelihood of complications, and likely result.