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Find video protocols related to scientific articles indexed in Pubmed.
Diagnostic yield of blood cultures from antibiotic-naïve and antibiotically treated patients with haematological malignancies and high-risk neutropenia.
Scand. J. Infect. Dis.
PUBLISHED: 06-30-2009
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In patients with prolonged episodes of neutropenia, infections are associated with significant mortality. The exact diagnostic yield of blood cultures in this high-risk population is still unclear. To assess the yield of blood cultures, the spectrum of pathogenic organisms and the influence of blood culture results on the therapeutic management, we retrospectively evaluated the results from 2520 blood cultures obtained from 126 consecutive patients with high-risk neutropenia. Bacterial pathogens were detected in 219 blood culture samples (8.7%) of which 172 were Gram-positive and 47 were Gram-negative bacteria. Fungal pathogens were found in 13 blood cultures. A higher rate of Gram-positive pathogens and of fungi was found in patients with central venous catheters. Pathogens were detected in 14.3% of blood cultures obtained before the institution of antibiotic treatment and in 7% of blood cultures obtained under antibiotic treatment. Treatment was modified in 116/232 (50%) of positive blood culture findings. In patients with high-risk neutropenia, blood cultures are a valid diagnostic tool, both in antibiotic-naïve patients and in patients receiving antibiotic treatment, and provide important information for clinical decision making. The epidemiological data obtained are helpful for selecting empirical antibiotic treatment regimens.
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Detection of Aspergillus DNA by a nested PCR assay is able to improve the diagnosis of invasive aspergillosis in paediatric patients.
J. Med. Microbiol.
PUBLISHED: 06-18-2009
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Fungal infections are a leading cause of morbidity and mortality in severely immunocompromised patients and have been increasing in incidence in recent years. Invasive aspergillosis (IA) is the most common filamentous fungal infection and is, in adults as well as in children, difficult to diagnose. Several PCR assays to detect Aspergillus DNA have been established, but so far, studies on molecular tools for the diagnosis of IA in children are few. We evaluated the results of a nested PCR assay to detect Aspergillus DNA in clinical samples from paediatric and adolescent patients with suspected IA. Blood and non-blood samples from immunocompromised paediatric and adolescent patients with suspected invasive fungal infection were sent for processing Aspergillus PCR to our laboratory. PCR results from consecutive patients from three university childrens hospitals investigated between November 2000 and January 2007 were evaluated. Fungal infections were classified according to the EORTC classification on the grounds of clinical findings, microbiology and radio-imaging results. Two hundred and ninety-one samples from 71 patients were investigated for the presence of Aspergillus DNA by our previously described nested PCR assay. Two, 3 and 34 patients had proven, probable and possible IA, respectively. Sensitivity (calculated from proven and probable patients, n=5) and specificity (calculated from patients without IA, n=32) rates of the PCR assay were 80 and 81 %, respectively. Our nested PCR assay was able to detect Aspergillus DNA in blood, cerebrospinal fluid and bronchoalveolar lavage samples from paediatric and adolescent patients with IA with high sensitivity and specificity rates.
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Cancer-causing karyotypes: chromosomal equilibria between destabilizing aneuploidy and stabilizing selection for oncogenic function.
Cancer Genet. Cytogenet.
PUBLISHED: 01-06-2009
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The chromosomes of cancer cells are unstable, because of aneuploidy. Despite chromosomal instability, however, cancer karyotypes are individual and quasi-stable, as is evident especially from clonal chromosome copy numbers and marker chromosomes. This paradox would be resolved if the karyotypes in cancers represent chromosomal equilibria between destabilizing aneuploidy and stabilizing selection for oncogenic function. To test this hypothesis, we analyzed the initial and long-term karyotypes of seven clones of newly transformed human epithelial, mammary, and muscle cells. Approximately 1 in 100,000 such cells generates transformed clones at 2-3 months after introduction of retrovirus-activated cellular genes or the tumor virus SV40. These frequencies are too low for direct transformation, so we postulated that virus-activated genes initiate transformation indirectly, via specific karyotypes. Using multicolor fluorescence in situ hybridization with chromosome-specific DNA probes, we found individual clonal karyotypes that were stable for at least 34 cell generations-within limits, as follows. Depending on the karyotype, average clonal chromosome numbers were stable within +/- 3%, and chromosome-specific copy numbers were stable in 70-100% cells. At any one time, however, relative to clonal means, per-cell chromosome numbers varied +/-18% and chromosome-specific copy numbers varied +/-1 in 0-30% of cells; unstable nonclonal markers were found within karyotype-specific quotas of <1% to 20% of the total chromosome number. For two clones, karyotypic ploidies also varied. With these rates of variation, the karyotypes of transformed clones would randomize in a few generations unless selection occurs. We conclude that individual aneuploid karyotypes initiate and maintain cancers, much like new species. These cancer-causing karyotypes are in flexible equilibrium between destabilizing aneuploidy and stabilizing selection for transforming function. Karyotypes as a whole, rather than specific mutations, explain the individuality, fluidity, and phenotypic complexity of cancers.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.