1,879 research outputs found
Large Quantum Superpositions and Interference of Massive Nanometer-Sized Objects
We propose a method to prepare and verify spatial quantum superpositions of a
nanometer-sized object separated by distances of the order of its size. This
method provides unprecedented bounds for objective collapse models of the wave
function by merging techniques and insights from cavity quantum optomechanics
and matter wave interferometry. An analysis and simulation of the experiment is
performed taking into account standard sources of decoherence. We provide an
operational parameter regime using present day and planned technology.Comment: 4 pages, 2 figures, to appear in PR
Significance of Extravascular Protein Binding for Antimicrobial Pharmacodynamics in an In Vitro Capillary Model of Infection
The effect of protein binding in an extravascular space on antimicrobial pharmacodynamics was studied in an in vitro capillary model of infection. Simulated 500-mg oral doses of dicloxacillin (~ 96% bound) or cephalexin (\u3c 5% bound) were administered every 6 h for four doses. A 10-fold-higher dose of dicloxacillin was also studied to determine the effect of drug concentration on the reduction of bacterial killing in the presence of protein. Staphylococcus aureus ATCC 25923 was inoculated into peripheral chambers filled with either Mueller-Hinton broth or Mueller-Hinton broth plus 25% human serum. Serial samples for bacterial counts were collected over 24 h. The presence of serum in the chambers significantly reduced bacterial killing by dicloxacillin but not by cephalexin during the first 6 h (two-way analysis of variance, F = 6.04, P \u3c 0.05) but not at 24 h. Reduction of dicloxacillin activity in serum-containing chambers persisted with the higher dose. These data suggest that despite attaining higher total drug concentrations in protein-containing extravascular spaces with highly bound drugs, protein binding reduces bactericidal activity during the early stages of treatment in this model
Combination Therapy with Ciprofloxacin plus Azlocillin against Pseudomonas aeruginosa: Effect of Simultaneous versus Staggered Administration in an In Vitro Model of Infection
The effect of dose scheduling on the pharmacodynamics of simulated human doses of ciprofloxacin (200 mg intravenously [iv] every 12 h) and azlocillin (4 g iv every 12 h) alone or in combination against Pseudomonas aeruginosa was studied in a two-compartment in vitro kinetic model of infection. Studies with the two drugs in combination were compared using simultaneous or staggered (first doses of each drug were administered 6 h apart) dosing schedules. Bacterial regrowth and resistance were prevented by all combination dosing schedules; however, the simultaneous regimen consistently provided the greatest extent of killing for all strains, particularly in those initially resistant to ciprofloxacin. These enhanced effects of the combination were corroborated by an increase in the peak and duration of bactericidal activity in the analogous "serum” compartment of the model. These data show the potential usefulness of simultaneous dosing of an antipseudomonal µ-lactam with ciprofloxacin against P. aeruginos
Efficient oxidative dearomatisations of substituted phenols using hypervalent iodine (iii) reagents and antiprotozoal evaluation of the resulting cyclohexadienones against T. b. rhodesiense and P. falciparum Strain NF54
Quinones and quinols are secondary metabolites of higher plants that are associated with many biological activities. The oxidative dearomatization of phenols induced by hypervalent iodine(III) reagents has proven to be a very useful synthetic approach for the preparation of these compounds, which are also widely used in organic synthesis and medicinal chemistry. Starting from several substituted phenols and naphthols, a series of cyclohexadienone and naphthoquinone derivatives were synthesized using different hypervalent iodine(III) reagents and evaluated for their in vitro antiprotozoal activity. Antiprotozoal activity was assessed against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. Cytotoxicity of all compounds towards L6 cells was evaluated and the respective selectivity indices (SI) were calculated. We found that benzyl naphthoquinone 5c was the most active and selective molecule against T. brucei rhodesiense (IC50 = 0.08 muM, SI = 275). Furthermore, the antiprotozoal assays revealed no specific effects. In addition, some key physicochemical parameters of the synthesised compounds were calculated
Walls talk: Microbial biogeography of homes spanning urbanization.
Westernization has propelled changes in urbanization and architecture, altering our exposure to the outdoor environment from that experienced during most of human evolution. These changes might affect the developmental exposure of infants to bacteria, immune development, and human microbiome diversity. Contemporary urban humans spend most of their time indoors, and little is known about the microbes associated with different designs of the built environment and their interaction with the human immune system. This study addresses the associations between architectural design and the microbial biogeography of households across a gradient of urbanization in South America. Urbanization was associated with households' increased isolation from outdoor environments, with additional indoor space isolation by walls. Microbes from house walls and floors segregate by location, and urban indoor walls contain human bacterial markers of space use. Urbanized spaces uniquely increase the content of human-associated microbes-which could increase transmission of potential pathogens-and decrease exposure to the environmental microbes with which humans have coevolved
Sialylation of campylobacter jejuni lipo-oligosaccharides: impact on phagocytosis and cytokine production in mice
<p>Background:
Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown.</p>
<p>Methodology/Principal Findings:
In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-β by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC.</p>
<p>Conclusions/Significance:
These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS</p>
High diagnostic yield of direct Sanger sequencing in the diagnosis of neuronal ceroid lipofuscinoses
Background: Neuronal ceroid lipofuscinoses are neurodegenerative disorders. To investigate the diagnostic yield of direct Sanger sequencing of the CLN genes, we reviewed Molecular Genetics Laboratory Database for molecular genetic test results of the CLN genes from a single clinical molecular diagnostic laboratory. Methods: We reviewed electronic patient charts. We used consent forms and Research Electronic Data Capture questionnaires for the patients from outside of our Institution. We reclassified all variants in the CLN genes. Results: Six hundred and ninety three individuals underwent the direct Sanger sequencing of the CLN genes for the diagnosis of neuronal ceroid lipofuscinoses. There were 343 symptomatic patients and 350 family members. Ninety-one symptomatic patients had molecular genetic diagnosis of neuronal ceroid lipofuscinoses including CLN1 (PPT1) (n = 10), CLN2 (TPP1) (n = 33), CLN3 (n = 17), CLN5 (n = 7), CLN6 (n = 10), CLN7 (MFSD8) (n = 10), and CLN8 (n = 4) diseases. The diagnostic yield of direct Sanger sequencing of CLN genes was 27% in symptomatic patients. We report detailed clinical and investigation results of 33 NCL patients. Juvenile onset CLN1 (PPT1) and adult onset CLN6 diseases were nonclassical phenotypes. Conclusion: In our study, the diagnostic yield of direct Sanger sequencing was close to diagnostic yield of whole exome sequencing. Developmental regression, cognitive decline, visual impairment and cerebral and/or cerebellar atrophy in brain MRI are significant clinical and neuroimaging denominators to include NCL in the differential diagnosis
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