Comparison of screening methods to identify methicillin-resistantStaphylococcus aureus

Screening methods to identify methicillin-resistantStaphylococcus aureus (MRSA) were compared using 96 isolates representing 17 distinct clones. The sensitivity of four commercial agglutination tests was determined in comparison to the tube coagulation test, and the results related to the presence of the coagulase gene. The broth screening test, agar dilution test and disc diffusion test were carried out, and the results related to the presence of themecA gene. Mannitol salt agar and Iso-Sensitest agar with varying salt supplements were used. All agglutination tests had high rates of detection ofStaphylococcus aureus (95.8–99.0%). Resistance in mecA gene-positiveStaphylococcus aureus isolates was correctly detected by the oxacillin broth test, the agar dilution test and the disc diffusion test on mannitol salt agar, whereas on Iso-Sensitest agar detection rates were lower (between 68.5% and 94.4%, depending on the salt supplement). Incubation of the Iso-Sensitest plates for 48 hours significantly improved the rate of detection of resistance, but increased the major error rate up to 71.4%.MecA genepositiveStaphylococcus aureus isolates not detected by the disc diffusion test on Iso-Sensitest agar had significantly lower oxacillin minimal inhibitory concentration values and were significantly less resistant to a variety of antibiotics. Thus, mannitol salt agar might be a suitable medium for use in the disc diffusion and agar dilution test to detect resistance to oxacillin inStaphylococcus aureus.     

Phase II trial of capecitabine/irinotecan and capecitabine/oxaliplatin in advanced gastrointestinal cancers

Combination protocols of 5-fluorouracil/leucovorin (5-FU/LV) plus irinotecan or oxaliplatin have demonstrated high activity in metastatic colorectal cancer. Capecitabine, an oral 5-FU prodrug, may replace infusional 5-FU/LV in combination protocols with irinotecan or oxaliplatin. We therefore initiated a phase II study with capecitabine plus either irinotecan or oxaliplatin to determine the efficacy and toxicity of specific combination protocols in patients with advanced gastrointestinal (GI) tumors. Capecitabine 1000 mg/m(2) taken orally twice a day on days 1-14, plus oxaliplatin 70 mg/m(2) on days 1 and 8, or irinotecan 100 mg/m(2) on days 1 and 8; repeated every 3 weeks in an outpatient setting. Patient and tumor characteristics were as follows: median age, 68 years (range, 34-77 years); sex: 10 women, 33 men; tumor types: 35 colorectal cancer; 8 other GI tumors including 5 gastric, 2 pancreatic, and 1 duodenal cancer. All 43 patients treated were evaluable for toxicity (capecitabine/oxaliplatin, 24 patients; capecitabine/irinotecan, 19 patients), and 39 were evaluable for efficacy (capecitabine/oxaliplatin, 22; capecitabine/irinotecan, 17). Grade 3/4 toxicities (National Cancer Institute Common Toxicity Criteria Version 2.0) were limited to diarrhea, 9 patients (capecitabine/irinotecan, n = 5; capecitabine/oxaliplatin, n = 4); hand-foot syndrome, 1 patient (capecitabine/irinotecan); nausea, 2 patients (capecitabine/oxaliplatin); vomiting, 1 patient (capecitabine/oxaliplatin); and peripheral neuropathy, 1 patient (capecitabine/oxaliplatin). No grade 3/4 myelosuppression was noted for either protocol. Capecitabine/irinotecan and capecitabine/oxaliplatin demonstrated significant clinical activity in colorectal cancer and other GI cancers as first-line and salvage therapy. Capecitabine/oxaliplatin and capecitabine/irinotecan show an excellent safety profile and clinical activity in colorectal cancer and other advanced GI tumors. The main toxicity in both arms was manageable diarrhea. This trial served as basis for a randomized multicenter phase II study comparing capecitabine/oxaliplatin and capecitabine/irinotecan as first-line therapy in patients with advanced colorectal cancer.     

Body size miniaturization in a lineage of colubrid snakes: Implications for cranial anatomy

As body size strongly determines the biology of an organism at all levels, it can be expected that miniaturization comes with substantial structural and functional constraints. Dwarf snakes of the genus Eirenis are derived from big, surface-dwelling ancestors, considered to be similar to those of the sister genus Dolichophis. To better understand the structural implications of miniaturization on the feeding apparatus in Eirenis, the morphology of the cranial musculoskeletal system of Dolichophis schmidti was compared with that of the miniature Eirenis punctatolineatus and E. persicus using high-resolution µCT data. The gape index was compared between D. schmidti and 14 Eirenis species. Our results show a relatively increased neurocranium size and decreased maximal jaw muscle force in E. persicus, compared with the D. schmidti, and an intermediate situation in E. punctatolineatus. A significant negative allometry in gape index relative to body size is observed across the transition from the Dolichophis to Pediophis and Eirenis subgenera. However, the gape index relative to head size showed a significant negative allometry only across the transition from the Dolichophis to Pseudocyclophis subgenus. In Dolichophis–Eirenis dwarfing lineages, different structural patterns are observed through miniaturization, indicating that overcoming the challenge of miniaturization has achieved via different adaptations.     

Surface roughness directed self-assembly of patchy particles into colloidal micelles

Colloidal particles with site-specific directional interactions, so called "patchy particles", are promising candidates for bottom-up assembly routes towards complex structures with rationally designed properties. Here we present an experimental realization of patchy colloidal particles based on material independent depletion interaction and surface roughness. Curved, smooth patches on rough colloids are shown to be exclusively attractive due to their different overlap volumes. We discuss in detail the case of colloids with one patch that serves as a model for molecular surfactants both with respect to their geometry and their interactions. These one-patch particles assemble into clusters that resemble surfactant micelles with the smooth and attractive sides of the colloids located at the interior. We term these clusters "colloidal micelles". Direct Monte Carlo simulations starting from a homogeneous state give rise to cluster size distributions that are in good agreement with those found in experiments. Important differences with surfactant micelles originate from the colloidal character of our model system and are investigated by simulations and addressed theoretically. Our new "patchy" model system opens up the possibility for self-assembly studies into finite-sized superstructures as well as crystals with as of yet inaccessible structures.     

Caspase 3-cleaved N-terminal fragments of wild-type and mutant huntingtin are present in normal and Huntington''s disease brains, associate with membranes, and undergo calpain-dependent proteolysis

The Huntington's disease (HD) mutation is a polyglutamine expansion in the N-terminal region of huntingtin (N-htt). How neurons die in HD is unclear. Mutant N-htt aggregates in neurons in the HD brain; expression of mutant N-htt in vitro causes cell death. Other in vitro studies show that proteolysis by caspase 3 could be important in regulating mutant N-htt function, but there has been no direct evidence for caspase 3-cleaved N-htt fragments in brain. Here, we show that N-htt fragments consistent with the size produced by caspase 3 cleavage in vitro are resident in the cortex, striatum, and cerebellum of normal and adult onset HD brain and are similar in size to the fragments seen after exogenous expression of human huntingtin in mouse clonal striatal neurons. HD brain extracts treated with active caspase 3 had increased levels of N-htt fragments. Compared with the full-length huntingtin, the caspase 3-cleaved N-htt fragments, especially the mutant fragment, preferentially segregated with the membrane fraction. Partial proteolysis of the human caspase 3-cleaved N-htt fragment by calpain occurred in vitro and resulted in smaller N-terminal products; products of similar size appeared when mouse brain protein extracts were treated with calpain. Results support the idea that sequential proteolysis by caspase 3 and calpain may regulate huntingtin function at membranes and produce N-terminal mutant fragments that aggregate and cause cellular dysfunction in HD.     

Subungual tumors in incontinentia pigmenti

A 22-year-old woman presented with intermittently painful subungual keratotic tumors of the hands as a late manifestation of incontinentia pigmenti. Scalloped bony deformities of the distal phalanges of both hands were noted on roentgenograms. The origin of these lytic deformities is uncertain; they may be secondary pressure phenomena or, alternatively, they may be an intrinsic manifestation of incontinentia pigmenti. These subungual tumors clinically resemble verrucae, keratoacanthomas, squamous cell carcinomas, or subungual fibromas. Therefore, it is important to recognize that subungual keratotic tumors may be a late manifestation of incontinentia pigmenti.     

Increased levels of IL-6 in the cerebrospinal fluid of patients with chronic schizophrenia — significance for activation of the kynurenine pathway

Background

Accumulating evidence indicates that schizophrenia is associated with brain immune activation. While a number of reports suggest increased cytokine levels in patients with schizophrenia, many of these studies have been limited by their focus on peripheral cytokines or confounded by various antipsychotic treatments. Here, well-characterized patients with schizophrenia, all receiving olanzapine treatment, and healthy volunteers were analyzed with regard to cerebrospinal fluid (CSF) levels of cytokines. We correlated the CSF cytokine levels to previously analyzed metabolites of the kynurenine (KYN) pathway.

Methods

We analyzed the CSF from patients and controls using electrochemiluminescence detection with regard to cytokines. Cell culture media from human cortical astrocytes were analyzed for KYN and kynurenic acid (KYNA) using high-pressure liquid chromatography or liquid chromatography/mass spectrometry.

Results

We included 23 patients and 37 controls in our study. Patients with schizophrenia had increased CSF levels of interleukin (IL)-6 compared with healthy volunteers. In patients, we also observed a positive correlation between IL-6 and the tryptophan:KYNA ratio, indicating that IL-6 activates the KYN pathway. In line with this, application of IL-6 to cultured human astrocytes increased cell medium concentration of KYNA.

Limitations

The CSF samples had been frozen and thawed twice before analysis of cytokines. Median age differed between patients and controls. When appropriate, all present analyses were adjusted for age.

Conclusion

We have shown that IL-6, KYN and KYNA are elevated in patients with chronic schizophrenia, strengthening the idea of brain immune activation in patients with this disease. Our concurrent cell culture and clinical findings suggest that IL-6 induces the KYN pathway, leading to increased production of the N-methyl-d-aspartate receptor antagonist KYNA in patients with schizophrenia.     

The influence of infantile handling, age and strain on alcohol selection in mice

Male mice from three inbred strains (C57B1/10J, BALB/cJ and C3H/2lbg) were assigned to infantile handling or control conditions. In a cross-sectional developmental design, handled and control mice were tested for two-choice selection of 10% (v/v) ethanol vs. tap water at 60, 90 or 120 days of age. The volume of fluid consumed from both tubes was recorded for fifteen days. In 60 day old mice, handling produced a trend toward increased total fluid consumption in the C57 mice and a trend toward increased ethanol selection in the BALBs. In 90 day old mice, there were trends noted toward handling-related decreased fluid consumption in BALBs. Also noted was a trend toward handling related increased ethanol selection in C57 mice. In 120 day old mice, a handling-related increase in alcohol selection was noted in the C3H strain.