Temporary blood–brain barrier disruption by low intensity pulsed ultrasound increases carboplatin delivery and efficacy in preclinical models of glioblastoma

Journal of Neuro-Oncology - Glioblastoma (GBM) is the most common and aggressive primary brain cancer in adults. Few cytotoxic chemotherapies have been shown to be effective against GBM, due in...     

How useful is GLUT-1 in differentiating mesothelial hyperplasia and fibrosing pleuritis from epithelioid and sarcomatoid mesotheliomas? An international collaborative study

Objective

Mesothelial hyperplasia (MH) and fibrosing pleuritis (FP) can be difficult to distinguish from epithelioid (MM-E) and sarcomatoid (MM-S) malignant pleural mesotheliomas. GLUT-1 has shown variable results regarding its sensitivity and specificity when used to evaluate mesothelial proliferations. We evaluated the utility of GLUT-1 immunostaining in differentiating MH and FP from MM-E and MM-S.

Materials and methods

In this retrospective study, diagnostically well-characterized cases (MH = 31, FP = 29, MM-E = 41, MM-S = 29) were collected and manually stained for GLUT-1. All slides were visually scored by 2 pathologists; using the following system: 0%, 1+ 1–25%, 2+ 26–50% and 3+ >51% cells staining.

Results

All benign cases (n = 60) were negative for GLUT-1 while 45 of 78 (58%) MM [21 of 41 (50%) MM-E, 21 of 29 (72%) MM-S and 3 of 3 biphasic mesothelioma (100%)] had 1+ to 3+ staining. Of the MM-E, 10 had 1+, and 11 had 2+ staining; of the MM-S 3 had 1+, 15 had 2+ and 3 had 3+ staining. Both sarcomatoid and epithelioid components of the 3 biphasic mesotheliomas revealed 1+ staining. All 5 desmoplastic MM were negative.

Conclusions

Positive staining with GLUT-1 is helpful since it is present in half of MM-E and three-quarter of MM-S. Although all reactive mesothelial lesions were negative, the absence of immunoreactivity does not exclude the diagnosis of MM. As with all IHC stains used for diagnostic purposes, GLUT-1 has to be a part of a panel, and the results interpreted in the context of clinical, radiological and histological findings.     

Prevalence of oropharyngeal beta-lactamase-producing <Emphasis Type="Italic">Capnocytophaga</Emphasis>spp. in pediatric oncology patients over a ten-year period

Background

The aim of this study was to evaluate the prevalence of beta-lactamase-producing Capnocytophaga isolates in young children hospitalized in the Pediatric Oncology Department of Hôpital Sud (Rennes, France) over a ten-year period (1993–2002).

Methods

In neutropenic children, a periodic survey of the oral cavity allows a predictive evaluation of the risk of systemic infections by Capnocytophaga spp. In 449 children with cancer, 3,053 samples were collected by oral swabbing and plated on TBBP agar. The susceptibility of Capnocytophaga isolates to five beta-lactams was determined.

Results

A total of 440 strains of Capnocytophaga spp. were isolated, 309 (70%) of which were beta-lactamase producers. The beta-lactamase-producing strains were all resistant to cefazolin, 86% to amoxicillin, and 63% to ceftazidime. The proportion of strains resistant to third-generation cephalosporins remained high throughout the ten-year study, while susceptibility to imipenem and amoxicillin combined with clavulanic acid was always conserved.

Conclusion

These results highlight the risk of antibiotic failure in Capnocytophaga infections and the importance of monitoring immunosuppressed patients and testing for antibiotic susceptibility and beta-lactamase production.

     

Specific and non-specific phagocytosis of ligand-grafted PLGA microspheres by macrophages

We evaluated the influence of ligand grafting on the rate and intensity of uptake of poly(d,l-lactide-co-glycolide) microparticles by alveolar macrophages. Microspheres with a mean diameter of 2.5 μm were obtained by spray drying. Three ligands (WGA, an RGD containing peptide and mannose-PEG₃-NH₂) and a cationic molecule (PLL) were covalently grafted on the particle surface using the carbodiimide method. Their grafting efficiency was quantified, and WGA grafting was characterized by confocal laser scanning microscopy (CLSM) and by atomic force microscopy (AFM). The uptake by macrophages of surface-modified microspheres was quantified by CLSM. This work showed that the uptake of negatively charged ligand-grafted microspheres (−26 to −51 mV) was increased up to two to four times according to the ligand compared to ungrafted microspheres (−81 mV) and displayed saturation as opposed to the cationic PLL-grafted microspheres. Moreover, a specific receptor-mediated phagocytosis mechanism was suggested based on free ligand, cytochalasin D and +4 °C incubation that decreased the microparticle uptake. Furthermore, this work clearly showed that the relative contribution of specific and non-specific processes to the overall uptake varied greatly according to the ligands, and was dependent on the particle-to-cell ratio. In conclusion, this work showed that ligand grafting can enhance the uptake of microparticles, with a variable relative contribution of specific and non-specific uptake mechanism.     

Imaging the interaction of HIV-1 genomes and Gag during assembly of individual viral particles

The incorporation of viral genomes into particles has never previously been imaged in live infected cells. Thus, for many viruses it is unknown how the recruitment and packaging of genomes into virions is temporally and spatially related to particle assembly. Here, we devised approaches to simultaneously image HIV-1 genomes, as well as the major HIV-1 structural protein, Gag, to reveal their dynamics and functional interactions during the assembly of individual viral particles. In the absence of Gag, HIV-1 RNA was highly dynamic, moving in and out of the proximity of the plasma membrane. Conversely, in the presence of Gag, RNA molecules docked at the membrane where their lateral movement slowed and then ceased as Gag assembled around them and they became irreversibly anchored. Viral genomes were not retained at the membrane when their packaging signals were mutated, nor when expressed with a Gag mutant that was not myristoylated. In the presence of a Gag mutant that retained membrane- and RNA-binding activities but could not assemble into particles, the viral RNA docked at the membrane but continued to drift laterally and then often dissociated from the membrane. These results, which provide visualization of the recruitment and packaging of genomes into individual virus particles, demonstrate that a small number of Gag molecules recruit viral genomes to the plasma membrane where they nucleate the assembly of complete virions.     

Optimal duration of antibiotic therapy in vertebral osteomyelitis

OBJECTIVES: To compare the risk of relapse of vertebral osteomyelitis (VO), according to the duration of antibiotic therapy (< or =6 weeks versus >6 weeks). METHODS: We performed a 10-year retrospective study to assess the risk of VO relapse and to verify that this risk was not enhanced in patients who received 6 weeks of antibiotic therapy (Group 1) as compared with those who received a longer treatment (Group 2). VO was diagnosed based on clinical manifestations, magnetic resonance imaging and/or computed tomography findings, and isolation of a pyogenic organism in blood cultures and/or a discovertebral biopsy. Relapse was diagnosed based on isolation of the same organism in blood cultures and/or a discovertebral biopsy. Outcome was evaluated 6 months post-treatment and in December 2004. RESULTS: Group 1 included 36 patients (mean age, 58 +/- 15 years) and Group 2 included 84 patients (mean age, 67 +/- 15 years) (P = 0.003). Clinical data and microorganisms were comparable in the 2 groups. In the first 6 months, 6 (5%) patients died (Group 1, n = 2; Group 2, n = 4), and 5 (4%) in Group 2 relapsed, 2 with recurrent VO and 3 with recurrent bacteremia. In 2004, 91 patients were evaluated (mean follow-up, 40.6 +/- 31 months): 77 (85%) were cured, 13 (14%) died (Group 1, n = 3; Group 2, n = 10), 1 had VO due to a different microorganism (Group 2), and no long-term relapses occurred. CONCLUSION: Our results suggest that antibiotic therapy of VO could be safely shortened to 6 weeks without enhancing the risk of relapse.     

Successful Pulmonary Embolectomy in a 4-Year-Old Girl with Antithrombin III Deficiency

We report the case of a 4-year-old girl, successfully treated by surgical pulmonary embolectomy for acute massive pulmonary embolism. She was known to have a congenital antithrombin III deficiency diagnosed after a familial history of thromboembolic events. Surgical embolectomy may be considered as a treatment option in selected patient with anatomically extensive pulmonary embolism.