2,621 research outputs found
Factors influencing the surgical process during shoulder joint replacement:Time-action analysis of five different prostheses and three different approaches
Factors influencing the surgical process during shoulder joint replacement:Time-action analysis of five different prostheses and three different approaches
Background: To evaluate the per-operative process of shoulder joint replacement, time-action analysis can be used.Material/Methods: Forty procedures performed by 7 surgeons with different experience rising 5 different prostheses and 3 different Surgical approaches were analyzed.Results: The surgical procedures showed a large variation in, for example, duration, tasks of team members, and protocol used. The surgical procedure was influenced by several factors, such as the prosthesis used, the surgical approach, the patient's condition, and the experience of the surgeon. Exposure of the glenoid was difficult and several retractors were needed, which were held by an extra assistant or clamped to the table or the surgeon. Two main limitations were seen in all procedures: repeated actions and waiting. Also, five errors could be identified. None of the alignment instruments was completely reliable and they allowed the surgeon to make major errors.Conclusions: Better alignment instruments, pre-operative planning techniques, and operation protocols are needed for shoulder prostheses. The training of resident surgeons should be focused on the exposure phase, the alignment of the humeral head, the exposure of the glenoid, and the alignment of the glenoid. Evaluating the surgical process using time-action analysis can be used to determine the limitations during surgical procedures. Furthermore, it shows the large variation in factors affecting surgical performance, indicating that a system approach is needed to improve surgical outcome.</p
Factors influencing the surgical process during shoulder joint replacement:Time-action analysis of five different prostheses and three different approaches
Chytrid epidemics may increase genetic diversity of a diatom spring-bloom
Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts
Optimal Surgical Extent for Memory and Seizure Outcome in Temporal Lobe Epilepsy
OBJECTIVE: Postoperative memory decline is an important consequence of anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), and the extent of resection may be a modifiable factor. This study aimed to define optimal resection margins for cognitive outcome while maintaining a high rate of postoperative seizure freedom. METHODS: This cohort study evaluated the resection extent on postoperative structural MRI using automated voxel-based methods and manual measurements in 142 consecutive patients with unilateral drug refractory TLE (74 left, 68 right TLE) who underwent standard ATLR. RESULTS: Voxel-wise analyses revealed that postsurgical verbal memory decline correlated with resections of the posterior hippocampus and inferior temporal gyrus, whereas larger resections of the fusiform gyrus were associated with worsening of visual memory in left TLE. Limiting the posterior extent of left hippocampal resection to 55% reduced the odds of significant postoperative verbal memory decline by a factor of 8.1 (95% CI 1.5-44.4, p=0.02). Seizure freedom was not related to posterior resection extent, but to the piriform cortex removal after left ATLR. In right TLE, variability of the posterior extent of resection was not associated with verbal and visual memory decline or seizures after surgery. INTERPRETATION: The extent of surgical resection is an independent and modifiable risk factor for cognitive decline and seizures after left ATLR. Adapting the posterior extent of left ATLR might optimize postoperative outcome, with reduced risk of memory impairment while maintaining comparable seizure-freedom rates. The current, more lenient, approach might be appropriate for right ATLR. This article is protected by copyright. All rights reserved
From DNA sequence to application: possibilities and complications
The development of sophisticated genetic tools during the past 15 years have facilitated a tremendous increase of fundamental and application-oriented knowledge of lactic acid bacteria (LAB) and their bacteriophages. This knowledge relates both to the assignments of open reading frames (ORF’s) and the function of non-coding DNA sequences. Comparison of the complete nucleotide sequences of several LAB bacteriophages has revealed that their chromosomes have a fixed, modular structure, each module having a set of genes involved in a specific phase of the bacteriophage life cycle. LAB bacteriophage genes and DNA sequences have been used for the construction of temperature-inducible gene expression systems, gene-integration systems, and bacteriophage defence systems.
The function of several LAB open reading frames and transcriptional units have been identified and characterized in detail. Many of these could find practical applications, such as induced lysis of LAB to enhance cheese ripening and re-routing of carbon fluxes for the production of a specific amino acid enantiomer. More knowledge has also become available concerning the function and structure of non-coding DNA positioned at or in the vicinity of promoters. In several cases the mRNA produced from this DNA contains a transcriptional terminator-antiterminator pair, in which the antiterminator can be stabilized either by uncharged tRNA or by interaction with a regulatory protein, thus preventing formation of the terminator so that mRNA elongation can proceed. Evidence has accumulated showing that also in LAB carbon catabolite repression in LAB is mediated by specific DNA elements in the vicinity of promoters governing the transcription of catabolic operons.
Although some biological barriers have yet to be solved, the vast body of scientific information presently available allows the construction of tailor-made genetically modified LAB. Today, it appears that societal constraints rather than biological hurdles impede the use of genetically modified LAB.
The influence of low-grade glioma on resting state oscillatory brain activity: a magnetoencephalography study
Purpose In the present MEG-study, power spectral analysis of oscillatory brain activity was used to compare resting state brain activity in both low-grade glioma (LGG) patients and healthy controls. We hypothesized that LGG patients show local as well as diffuse slowing of resting state brain activity compared to healthy controls and that particularly global slowing correlates with neurocognitive dysfunction. Patient and methods Resting state MEG recordings were obtained from 17 LGG patients and 17 age-, sex-, and education-matched healthy controls. Relative spectral power was calculated in the delta, theta, upper and lower alpha, beta, and gamma frequency band. A battery of standardized neurocognitive tests measuring 6 neurocognitive domains was administered. Results LGG patients showed a slowing of the resting state brain activity when compared to healthy controls. Decrease in relative power was mainly found in the gamma frequency band in the bilateral frontocentral MEG regions, whereas an increase in relative power was found in the theta frequency band in the left parietal region. An increase of the relative power in the theta and lower alpha band correlated with impaired executive functioning, information processing, and working memory. Conclusion LGG patients are characterized by global slowing of their resting state brain activity and this slowing phenomenon correlates with the observed neurocognitive deficits
Evaluation of 3D T1-weighted imaging at 3T across scanner vendors and models
Volumetric analyses of 3D T1-weighted images has become an integral part of the clinical work-up and
research studies. Variation between scanners, in both vendors and models, is a major confound in
combining imaging-derived biomarkers across sites. In this work, we analyse test-retest data from
di×erent days on six 3 T scanners from three vendors to quantify this inter-scanner variability compared
to intra-scanner variability. Contrast-to-noise ratios as well as volumetric analyses are performed
showing between-scanner variation in total brain volumes – indicating di×erent scanner calibrations –
but also tissue-speciÒc di×erences – possibly arising from di×erent e×ective contrasts
Thin-section Computed Tomography findings before and after azithromycin treatment of neutrophilic reversible lung allograft dysfunction
Recently a novel subgroup of bronchiolitis obliterans syndrome (BOS) has been described in patients after lung transplantation with high neutrophil counts in broncho-alveolar lavage and recovery of lung functional decline with azithromycin treatment. We aimed to describe the thin-section computed tomography (CT) findings of these neutrophilic reversible allograft dysfunction (NRAD) patients before and after azithromycin.status: publishe
Use of genetically modified bacteria for drug delivery in humans: Revisiting the safety aspect
The use of live, genetically modified bacteria as delivery vehicles for biologics is of considerable interest scientifically and has attracted significant commercial investment. We have pioneered the use of the commensal gut bacterium Bacteroides ovatus for the oral delivery of therapeutics to the gastrointestinal tract. Here we report on our investigations of the biological safety of engineered B. ovatus bacteria that includes the use of thymineless death as a containment strategy and the potential for the spread of transgenes in vivo in the mammalian gastrointestinal tract. We demonstrate the ability of GM-strains of Bacteroides to survive thymine starvation and overcome it through the exchange of genetic material. We also provide evidence for horizontal gene transfer in the mammalian gastrointestinal tract resulting in transgene-carrying wild type bacteria. These findings sound a strong note of caution on the employment of live genetically modified bacteria for the delivery of biologics
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