Clinical evaluation of the normalized metal artefact reduction algorithm caused by dental fillings in CT

OBJECTIVES

The aim of this study was to evaluate the performance of a normalized metal artefact reduction (NMAR) algorithm in patients with high-density dental fillings in CT images, and compare the results with weighted filtered back-projection (WFBP) and linear interpolation metal artefact reduction (MARli) algorithms.

METHODS

A total of 15 patients who had dental fillings were included in this study. The CT raw data sets were processed on an offline workstation. For each data set, one image series was reconstructed with WFBP, one with MARli and one with NMAR. Two observers qualitatively graded the severity of metal artefacts and their impacts on surrounding and distant soft tissue using a five-point scale. Six regions of interest were selected to measure the CT values and the standard deviation (SD) for quantitatively evaluating the effects of artefact reduction.

RESULTS

A total of 217 slices with metal artefacts from 15 patients were included in the qualitative analysis. The average score (mean ± SD) with the WFBP and MARli algorithms was 2.24 ± 1.06 and 2.71 ± 0.73, respectively. Image artefacts were significantly reduced using the NMAR algorithm compared with the other two algorithms, with an average score of 1.70 ± 0.83. The mean CT value in the most hypodense streak artefacts around the metal fillings was significantly improved with both MARli and NMAR. The mean SDs of measured CT values from surrounding or distant soft tissues were lower in NMAR images than in WFBP and MARli images.

CONCLUSIONS

The NMAR algorithm can significantly reduce the artefacts caused by dental fillings, compared with the WFBP and linear interpolation algorithms.

Successful isolation of equine mesenchymal stromal cells from cryopreserved umbilical cord blood-derived mononuclear cell fractions

REASONS FOR PERFORMING STUDY

The therapeutic potential of mesenchymal stromal cells for cellular therapy has generated increasing interest in human as well as veterinary medicine. Considerable research has been performed on the cryopreservation of expanded mesenchymal stromal cells, but little information is available on the cryopreservation of the original mononuclear cell fraction.

OBJECTIVES

The present study describes a protocol to expand equine mesenchymal stromal cells after cryopreserving the mononuclear cells of umbilical cord blood.

METHODS

To this end, mononuclear cells were isolated from 7 umbilical cord blood samples and cryopreserved at a concentration of 1-2 × 10(9) cells/l cold freezing solution. Cells were cryopreserved and kept frozen for at least 6 months before thawing. Frozen cryotubes were thawed in a 37°C water bath. Putative equine mesenchymal stromal cells were immunophenotyped using multicolour flow cytometry based on a selected 9 marker panel.

RESULTS

Average cell viability upon thawing was 98.7 ± 0.6%. In 6 out of 7 samples, adherent spindle-shaped cell colonies were observed within 9.0 ± 2.6 days and attained 80% confluency at 12.3 ± 3.9 days. After 3 passages, putative equine mesenchymal stromal cells were successfully immunophenotyped as CD29, CD44 and CD90 positive, and CD45, CD73, CD79α, CD105, MHC II and monocyte-marker negative.

CONCLUSIONS AND POTENTIAL RELEVANCE

Equine mesenchymal stromal cells can be cultured after cryopreservation of the isolated mononuclear cells, a time- as well as cost-efficient approach in equine regenerative medicine.

Ametropic amblyopia

Hypermetropia of more than 5 diopters or an astigmatism of 2 diopters or more is often the cause of amblyopia in the master eye, independent of the presence of a simultaneous strabismus or anisometropia. This amblyopia can be prevented with early spectacle correction. In the authors' study of 218 patients with high ametropia a correlation was not always present between visual acuity and the age of the first spectacle correction or the degree of ametropia. In some patients even correction of ametropia as late as seven to ten years of age led to spontaneous functional improvement of single optotypes acuity. The treatment of choice is to give the full ametropic correction at an early age.

[Excess mortality and prolongation of stay due to bloodstream infections caused by multiresistant pathogens in Germany]

BACKGROUND

Multiresistant pathogens cause substantial excess mortality and prolongation of hospital stay. However, until now there are no reliable estimates for Germany.

METHOD

Based on data of three recent publications from Europe and current German data on bloodstream infections because of methicillin-resistant S. aureus (MRSA) and extended spectrum beta-lactamase (ESBL) producing E. coli we calculated the number of patients dying from bloodstream infections because of MRSA- instead of methicillin-susceptible S. aureus (MSSA) or ESBL-producing E. coli instead of non-ESBL E. coli.

RESULTS

About 421 patients died in 2010 because they suffered from MRSA bloodstream infection instead of MSSA bloodstream infection. Excess mortality for bloodstream infections because ESBL-producing E. coli instead of non-ESBL E. coli was about 256 cases. Considering that bloodstream infections with other multiresistant pathogens also lead to higher mortality, between 800 to 1000 deaths can be expected because of the resistant variant of the pathogens. In addition, bloodstream infections with multiresistant pathogens lead to more than 12000 additional days in hospital in Germany.

CONCLUSION

Although this article does not include the burden of other healthcare-associated infections due to multiresistant pathogens the data for bloodstream infections alone demonstrate substantial excess burden and costs.

Contrast inversion of the h-BN nanomesh investigated by nc-AFM and Kelvin probe force microscopy

Single sheets of hexagonal boron nitride (h-BN) on transition metals provide a model system for layered insulating materials as well as a functional substrate for molecules and metal clusters. The progress in the understanding of h-BN layers on transition metals was mainly driven by scanning tunnelling microscopy (STM) and photoelectron spectroscopy (PES) measurements within the last decade, while direct measurements of mechanical and electrical properties are still rare. Our investigations of the two-dimensional (2D) h-BN nanomesh on a Rh(111) substrate by high-resolution noncontact atomic force microscopy (nc-AFM) reveal a complex surface structure including a frequently observed contrast inversion. Detailed 2D force spectroscopy measurements are revealing towards a mechanical elastic deformation of the h-BN monolayer caused by the tip-sample interaction. Furthermore, Kelvin probe force microscopy (KPFM) and spectroscopy measurements show local work function variations of the nanomesh, proving the results obtained by PES but additionally providing detailed local information.

Study of cnidarian-algal symbiosis in the "omics" age

The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium.

Transcriptome analysis and gene expression atlas for Panicum hallii var. filipes, a diploid model for biofuel research

Panicum hallii is an emerging model for genetic studies of agronomic traits in Panicum, presenting a tractable diploid alternative study system to the tetra- or octaploid biofuel crop switchgrass (Panicum virgatum). To characterize the gene complement in P. hallii var. filipes and enable gene expression analysis in this system we sequenced, assembled, and annotated the transcriptome. Over 300 Mb of normalized cDNA prepared from multiple tissues and treatments was sequenced using 454-Titanium, producing an annotated assembly including 15 422 unique gene names. Comparison with other grass genomes identified putative P. hallii homologs for >14 000 previously characterized genes. We also developed an atlas of gene expression across tissues and stages using RNA-Seq (the quantitative analysis of short cDNA reads). SOLiD sequencing and quantitative analysis of more than 40 million cDNA tags identified substantial variation in expression profiles among tissues, consistent with known functional differences. Putative homologs were found for all enzymes in the phenylpropanoid pathway leading to lignin biosynthesis, including genes with known effects on biomass conversion efficiency. The resources developed here will enable studies of the genes underlying variation in cell wall composition, drought tolerance, and biomass production in Panicum.

Long-term follow-up of renal function in dogs after treatment for ACTH-dependent hyperadrenocorticism

BACKGROUND

Systemic hypertension and proteinuria are frequent complications in dogs with Cushing's syndrome and do not always resolve after treatment of hypercortisolism. Therefore, dogs with Cushing's syndrome may be at risk for renal dysfunction before and after treatment.

HYPOTHESIS/OBJECTIVES

To assess renal function in dogs with ACTH-dependent hyperadrenocorticism (ADHAC) before and after treatment.

ANIMALS

A total of 19 dogs with ADHAC and 12 control dogs.

METHODS

Renal function was assessed before and at 1, 3, 6, and 12 months after treatment. Twelve dogs were treated with trilostane and 7 dogs by transsphenoidal hypophysectomy. Routine renal markers were measured and urinary albumin (uALB), immunoglobulin G (uIgG), and retinol-binding protein (uRBP) were assessed by ELISA. Urinary N-acetyl-β-D-glucosaminidase (uNAG) was determined colorimetrically. All urinary markers were indexed to urinary creatinine concentration (c). Plasma clearance of creatinine (Cl(creat)), exo-iohexol (Cl(exo)), and endo-iohexol (Cl(endo)) was used to measure glomerular filtration rate (GFR). Data were analyzed using a general linear model.

RESULTS

Serum creatinine and urea concentrations increased post-treatment, but remained within reference ranges. Plasma Cl(creat) and Cl(endo) were significantly lower post-treatment, whereas Cl(exo) was not different. Urinary protein-to-creatinine ratio (UPC), uALB/c, uIgG/c, and uRBP/c were decreased post-treatment, but at 12 months 5/13 dogs remained proteinuric. Urinary NAG/c did not change significantly.

CONCLUSIONS AND CLINICAL IMPORTANCE

A decrease in GFR and persistent proteinuria post-treatment may warrant the clinician's attention. Future research including renal histopathology of dogs with persistent proteinuria or low GFR is needed to further assess renal outcome.

Buccal fat pad - a simple, underutilised flap

The pedicled buccal fat pad is a reliable flap for the repair of small oral defects. It is durable, easy to harvest and should be considered in settings where access to free flaps is limited and in cases where previous flaps have failed. We discuss a case where this flap was used successfully for closure of an oro-antral fistula. The indications, anatomy and techniques of successful harvest are discussed.

Microsatellite markers for the native Texas perennial grass, Panicum hallii (Poaceae)

PREMISE OF THE STUDY

We developed microsatellites for Panicum hallii for studies of gene flow, population structure, breeding experiments, and genetic mapping.

METHODS AND RESULTS

Next-generation (454) genomic sequence data were used to design markers. Eighteen robust markers were discovered, 15 of which were polymorphic across six accessions of P. hallii var. hallii. Fourteen of the markers cross-amplified in a P. capillare accession. For the 15 polymorphic markers, the total number of alleles per locus ranged from two to 26 (mean: 11.0) across six populations (11-19 individuals per population). Observed heterozygosity (mean: 0.031) was 13.7 times lower than the expected heterozygosity (mean: 0.426).

CONCLUSIONS

The deficit of heterozygous individuals is consistent with P. hallii having a high rate of self-fertilization. These markers will be useful for studies in P. hallii and related species.

High-resolution imaging of C60 molecules using tuning-fork-based non-contact atomic force microscopy

Recent advances in non-contact atomic force microscopy (nc-AFM) have led to the possibility of achieving unprecedented resolution within molecular structures, accomplished by probing short-range repulsive interaction forces. Here we investigate C(60) molecules adsorbed on KBr(111) and Cu(111) by tuning-fork-based nc-AFM. First, measurements of C(60) deposited on KBr(001) were conducted in cryogenic conditions revealing highly resolved nc-AFM images of the self-assembly. Using constant-frequency shift mode as well as three-dimensional spectroscopic measurements, we observe that the relatively weak molecule-substrate interaction generally leads to the disruption of molecular assembled structures when the tip is probing the short-range force regime. This particular issue hindered us in resolving the chemical structure of this molecule on the KBr surface. To obtain a better anchoring of C(60) molecules, nc-AFM measurements were performed on Cu(111). Sub-molecular resolutions within the molecules was achieved which allowed a direct and unambiguous visualization of their orientations on the supporting substrate. Furthermore, three-dimensional spectroscopic measurements of simultaneous force and current have been performed above the single molecules giving information of the C(60) molecular orientation as well as its local conductivity. We further discuss the different imaging modes in nc-AFM such as constant-frequency shift nc-AFM, constant-height nc-AFM and constant-current nc-AFM as well as three-dimensional spectroscopic measurement (3D-DFS) employed to achieve such resolution at the sub-molecular scale.

Three-dimensional dynamic force spectroscopy measurements on KBr(001): atomic deformations at small tip-sample separations

Three-dimensional dynamic force spectroscopy measurements were carried out above KBr(001) at low temperature in order to investigate the distance dependence of the tip-sample interactions. In particular, the recorded 3D frequency shift data as well as the extracted interaction force and potential energy fields were analysed with respect to influences of tip and/or sample deformations. We found that a postprocessing correction of the observed deformations significantly modifies the magnitude of the extracted interaction forces and also the image contrast.

Multi-domain GFP-like proteins from two species of marine hydrozoans

Proteins homologous to Green Fluorescent Protein (GFP) are widely used as genetically encoded fluorescent labels. Many developments of this technology were spurred by discoveries of novel types of GFP-like proteins (FPs) in nature. Here we report two proteins displaying primary structures never before encountered in natural FPs: they consist of multiple GFP-like domains repeated within the same polypeptide chain. A two-domain green FP (abeGFP) and a four-domain orange-fluorescent FP (Ember) were isolated from the siphonophore Abylopsis eschscholtzii and an unidentified juvenile jellyfish (order Anthoathecata), respectively. Only the most evolutionary ancient domain of Ember is able to synthesize an orange-emitting chromophore (emission at 571 nm), while the other three are purely green (emission at 520 nm) and putatively serve to maintain the stability and solubility of the multidomain protein. When expressed individually, two of the green Ember domains form dimers and the third one exists as a monomer. The low propensity for oligomerization of these domains would simplify their adoption as in vivo labels. Our results reveal a previously unrecognized direction in which natural FPs have diversified, suggesting new avenues to look for FPs with novel and potentially useful features.

Chitinase-like proteins are candidate biomarkers for sepsis-induced acute kidney injury

Sepsis-induced acute kidney injury (AKI) is a frequent complication of critically ill patients and leads to high mortality rates. The specificity of currently available urinary biomarkers for AKI in the context of sepsis is questioned. This study aimed to discover urinary biomarkers for septic AKI by contemporary shotgun proteomics in a mouse model for sepsis and to validate these in individual urine samples of mice and human septic patients with and without AKI. At 48 h after uterine ligation and inoculation of Escherichia coli, aged mice (48 weeks) became septic. A subgroup developed AKI, defined by serum creatinine, blood urea nitrogen, and renal histology. Separate pools of urine from septic mice with and without AKI mice were collected during 12 h before and between 36-48 h after infection, and their proteome compositions were quantitatively compared. Candidate biomarkers were validated by Western blot analysis of urine, plasma, and renal tissue homogenates from individual mice, and a limited number of urine samples from human septic patients with and without AKI. Urinary neutrophil gelatinase-associated lipocalin, thioredoxin, gelsolin, chitinase 3-like protein 1 and -3 (CHI3L3) and acidic mammalian chitinase were the most distinctive candidate biomarkers selected for septic AKI. Both neutrophil gelatinase-associated lipocalin and thioredoxin were detected in urine of septic mice and increased with severity of AKI. Acidic mammalian chitinase was only present in urine of septic mice with AKI. Both urinary chitinase 3-like protein 1 and -3 were only detected in septic mice with severe AKI. The human homologue chitinase 3-like protein 1 was found to be more excreted in urine from septic patients with AKI than without. In summary, urinary chitinase 3-like protein 1 and -3 and acidic mammalian chitinase discriminated sepsis from sepsis-induced AKI in mice. Further studies of human chitinase proteins are likely to lead to additional insights in septic AKI.

Spectroscopic reflectometry of mirror surfaces during plasma exposure

An in situ spectroscopic reflectometry system has been built to investigate the evolution of the specular reflectivity spectrum of ITER first mirror samples during plasma exposure. Results are presented for three different types of molybdenum mirror samples that were exposed to deuterium plasma, including single crystalline, nanocrystalline, and polycrystalline molybdenum. The results show good agreement with ex situ measurements of the reflectivity spectrum before and after exposure and extend the results obtained in previous experiments.

Understaffing, overcrowding, inappropriate nurse:ventilated patient ratio and nosocomial infections: which parameter is the best reflection of deficits?

BACKGROUND

In stressed and high-throughput systems, periodic overcrowding (high bed occupancy) and understaffing (low nurse:patient ratio) are widely described risk factors for nosocomial infections.

AIM

The impact of bed occupancy (patient:bed ratio), nurse:patient ratio and nurse:ventilated patient ratio on nosocomial bloodstream infections (BSI) and pneumonia were investigated in 182 intensive care units (ICU).

METHODS

The ICUs reported monthly data on device use and nosocomial device-associated infections to the German hospital surveillance system for nosocomial infections in 2007. Information on the number of healthcare workers on the ward per 24h in 2007 and structure parameters was obtained by questionnaires. The association between occupancy or staff parameters and the number of nosocomial infections per month was analysed using generalized estimating equation models.

FINDINGS

In total, 1313 cases of pneumonia and 513 cases of BSI were reported from 182 ICUs with 1921 surveillance months and 563,177 patient-days. Fewer nosocomial infections were associated with a higher nurse:ventilated patient ratio [adjusted incidence rate ratio 0.42 (95% confidence interval 0.32-0.55) for months with nurse:ventilated patient ratios >75th percentile compared with ≤ 25 th percentile]. Interestingly, the nurse:patient ratio was not a significant parameter with respect to the occurrence of BSI and pneumonia. High bed occupancy (>75th percentile) was associated with fewer nosocomial infections.

CONCLUSION

A staffing parameter that reflects the intensity of care, such as the nurse:ventilated patient ratio, may enable better evaluation of workload and resources, especially at a time when nursing resources are being reduced but nosocomial infections are increasing.