Multicontrast MRI of remyelination in the central nervous system

Although magnetic resonance imaging (MRI) represents the most sensitive tool for the detection of white matter abnormalities in patients with multiple sclerosis (MS), the heterogeneity of MS placques severely hampers the elucidation of specific pathophysiological processes. In order to identify putative MRI markers for de- and remyelination, we employed the cuprizone mouse model which leads to a selective and reversible demyelination of the corpus callosum with little or no axonal damage. Apart from histopathology, animals were studied with high-resolution three-dimensional MRI in vivo using multiple contrasts. While individual MRI findings significantly correlated with electron microscopy, the differentiation of regions with normal, demyelinated or remyelinated white matter by one contrast alone was less specific than by histology or electron microscopy. However, an accurate MRI prediction of the in vivo myelin status was achieved by a discriminant function analysis using a combination of T1, T2 and magnetization transfer contrast. With a correct assignment of 95% of all animals examined, the procedure will allow for the survey of new therapeutic approaches aiming at improved remyelination.     

Frequent carriage of Panton-Valentine leucocidin genes by Staphylococcus aureus isolates from surgically drained abscesses

Between 1 February and 15 April 2002, 95 patients were admitted to Gaston Bourret Territorial Hospital (New Caledonia, France) for drainage of community-acquired soft tissue abscesses. Staphylococcus aureus was detected in 68 cases (72%). Two-thirds of the patients with S. aureus infection had furuncles, which were located on the limbs in 82% of cases. The median interval between symptom onset and hospital admission was 5.7 days. Three-quarters of the patients were Melanesians living in tribes. Fifty-four S. aureus isolates were screened for toxin genes. Panton-Valentine leucocidin (PVL) genes were detected in 48 isolates (89%), the exfoliative toxin A gene was detected in 1 isolate, and no toxin genes were detected in 4 isolates. S. aureus nasal carriage was detected in 39.7% of patients with S. aureus infections. Two infecting S. aureus strains and two nasal carriage strains were resistant to methicillin. Comparative pulsed-field gel electrophoresis, performed in 16 cases, showed that five of six patients with PVL-positive nasal carriage strains were infected by the same strains. In contrast, 8 of 10 patients with PVL-negative nasal carriage strains were infected by PVL-positive strains. PVL genes thus appear to be a major virulence factor in both primary and secondary S. aureus skin infections.     

Enterolith ileus due to jejunal diverticulosis

Jejunal diverticulosis is a rare malformation that is often asymptomatic. Complications might be similar to those occurring in large-bowel diverticula but also include a much more particular event: intestinal obstruction due to migration and impaction of enterolith formed inside diverticula. This is a very uncommon entity; diagnosis and management are thus often delayed. Mostly surgical exploration is necessary because obstruction symptoms are unresponsive to medical treatment. The authors report a new case of enterolith ileus in a 74-year-old man, due to jejunal diverticulosis, and its successful surgical management in emergency. Only 39 similar cases have ever been reported in the literature.     

Needlescopic appendectomy

Background: In this paper, we compare our experience with the techniques of needlescopic appendectomy (NA) (2-mm instruments) for the treatment of acute appendicitis with the more conventional approach of a laparoscopic appendectomy (LA). Methods: We did a retrospective review of patients who underwent NA for the diagnosis of acute appendicitis between August 1996 and January 2002. Variables including operative time, blood loss, postoperative time to discharge, intra- and postoperative complications were analyzed and compared to data from control patients who had undergone an LA for acute appendicitis. Results: The NA group had a longer average operating time (54.5 ± l3 vs. 42.5 ± 12.6 min, p = 0.0001) and a longer postoperative hospital stay (2.1 ± 1.4 vs. 1.3 ± 1.1 days, p = 0.01). Blood loss was similar for the two groups. Conclusions: With the exception of superior cosmesis, NA appears to have little advantage over the better-established LA; moreover, it has some disadvantages. A clearer benefit of this procedure over LA, as well as improvements in instrumentation, needs to be shown before it can be widely accepted. Presented in poster format at the 8th World Congress of Endoscopic Surgery, NewYork, NY, USA, 13–16 March 2002     

Replacing liquid with solid dosage forms in pediatric practice: Feasibility and economic impact from a hospital-based study

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Common determinants of antimicrobial resistance in sequential episodes of sexually transmitted shigellosis in men who have sex with men: a cross-sectional study

Background

In high-income nations, men who have sex with men (MSM) are at increased risk of shigellosis. A sublineage of Shigella flexneri serotype 3a was recently shown to have spread worldwide in MSM, driven by mobilisable azithromycin resistance. Since then, the serotype 2a and the species S sonnei have become epidemic in the UK. We aimed to determine whether these subsequent outbreaks were also attributable to epidemic sublineages in MSM and mobilisable antimicrobial resistance.

The High Diversity of MRSA Clones Detected in a University Hospital in Istanbul

Background: To characterize the methicillin-resistant Staphylococcus aureus (MRSA) clones present in Istanbul, 102 MRSA isolates collected during a 5-year period at the Istanbul Medical Faculty Hospital were characterized using microarray analysis and phenotypic resistance profiles.Methods: Resistance to methicillin was detected with a cefoxitin disk diffusion assay and confirmed with a MRSA-agar and MRSA detection kit. Antimicrobial susceptibility testing was performed by a disk diffusion assay and interpreted according to the 2012 guidelines of the Antibiogram Committee of the French Society for Microbiology. Decreased susceptibility to glycopeptides was confirmed using the population analysis profile-area under the curve (PAP-AUC) method. The presence of the mecA gene was detected by polymerase chain reaction. Bacterial DNA was extracted according to the manufacturer''s recommended protocol using commercial extraction kits. Strains were extensively characterized using the DNA microarray.Results: Isolates were grouped into six clonal complexes. The most frequently detected clone was the Vienna/Hungarian/Brazilian clone (ST239-MRSA-III), which accounted for 53.9% of the isolates. These isolates were resistant to multiple antibiotics, particularly penicillin, tetracycline, rifampicin, kanamycin, tobramycin, gentamicin, levofloxacin, erythromycin, lincomycin and fosfomycin. Furthermore, three isolates were detected by population analysis profile as heterogeneous vancomycin-intermediate S. aureus (hVISA). The UK-EMRSA-15 clone (ST22-MRSA-IV PVL negative) was detected in 9.8% of the isolates and was mainly susceptible to all anti-staphylococcal antibiotics. Seven isolates (6.9%) were positive for PVL genes and were assigned to the CC80-MRSA-IV clone (European CA-MRSA clone, three isolates), ST8-MRSA-IV clone (USA300 clone, two isolates, one ACME-positive) or ST22-MRSA-IV clone (“Regensburg EMRSA” clone, two isolates). All other clones were detected in one to six isolates and corresponded to well-known clones (e.g., Pediatric clone, Dublin EMRSA clone, WA MRSA-54/63, WA MRSA-1/57).Conclusions: This work highlighted both the high prevalence of ST239-MRSA-III clone and the large diversity of the other MRSA clones detected in a university hospital in Istanbul.     

A review of combined experimental and computational procedures for assessing biopolymer structure-process-property relationships

Tailored biomaterials with tunable functional properties are desirable for many applications ranging from drug delivery to regenerative medicine. To improve the predictability of biopolymer materials functionality, multiple design parameters need to be considered, along with appropriate models. In this article we review the state of the art of synthesis and processing related to the design of biopolymers, with an emphasis on the integration of bottom-up computational modeling in the design process. We consider three prominent examples of well-studied biopolymer materials - elastin, silk, and collagen - and assess their hierarchical structure, intriguing functional properties and categorize existing approaches to study these materials. We find that an integrated design approach in which both experiments and computational modeling are used has rarely been applied for these materials due to difficulties in relating insights gained on different length- and time-scales. In this context, multiscale engineering offers a powerful means to accelerate the biomaterials design process for the development of tailored materials that suit the needs posed by the various applications. The combined use of experimental and computational tools has a very broad applicability not only in the field of biopolymers, but can be exploited to tailor the properties of other polymers and composite materials in general.