未成年人解脲支原体DNA检测

目的:为了解未成年人UU感染特点。方法:FQ PCR方法用于定量检测未成年人和成年人样本中的UU DNA。结果:未成年人UU DNA阳性率(28.57%,24/84)显著小于成年人(48.87%,2569/5257)(χ2=13.64,P=0.00022),而UU DNA载量(5.72±1.11)则高于成年人(4.69±1.42)(t=3.54,P=0.00040);未成年女性感染阳性率(31.51%,23/73)显著低于成年人(55.10%,2238/4062)(χ2=16.10,P=6.00E-5),而载量(5.71±1.14)则高于成年女性(5.00±1.52)(t=2.21,P=0.027)。两组男性感染率则无统计学差异(χ2=1.87,P=0.17)。结论:未成年人UU DNA感染率显著小于成年人,UU DNA载量则高于成年人。     

Simulation of 125I-based radioprobing experiments to study DNA quadruplex structure and topology

Purpose: Certain guanine-rich DNA sequences have the capacity to fold into four-stranded structures stabilized by the stacking of square planar arrangements of four hydrogen-bonded guanine bases. However both the overall topology of folding and the more detailed three dimensional structure of these quadruplexes is difficult to determine or predict, and they can be polymorphic, altering radically depending on environmental conditions. Radioprobing experiments, in which Auger electrons emitted during the decay of a ¹²⁵I-containing base induce strand cleavage in a distance- and structure-dependent manner, have provided possible means of determining these details. Here we have used a combination of computer simulation methods to study the information obtained by one such experiment, reported in 2004.

Method: Models were constructed of three quadruplex topologies considered in the experiment, and one other topology proposed more recently. Molecular Dynamics simulations were used to equilibrate these structures and monitor how they evolved over several nanoseconds in solution. Snapshots from the trajectories were then subjected to Monte Carlo track structure prediction, from which theoretical cleavage patterns have been extracted.

Results: The four topologies were found to yield quite different cleavage patterns, which allow the presence of particular conformations in an experiment to be predicted.

Conclusion: Radioprobing, which is usable in biologically relevant environments, is sensitive enough to distinguish with some confidence between alternative folding topologies in a DNA structure. Monte Carlo track structure simulation can reinforce or question conclusions drawn from experiment, and Molecular Dynamics used with various restraints provides a practical means of guiding a model towards one that yields cleavage patterns closer to those found experimentally.     

Epigenetics of oral infection and inflammatory diseases—DNA methylation changes in infections and inflammation diseases

BackgroundEpigenetics involves alterations in gene expression that do not involve modifications in the DNA sequence, the memory of which can be passed down to the next generation in somatic cells. DNA methylation is an example of a mechanism that produces epigenetic changes. The purpose of this review is to summarize recent publications on DNA methylation in oral infections and inflammatory diseases, and to discuss its potential as a cause of disease and as a therapeutic target.HighlightSeveral types of oral bacteria and viruses may lead to DNA hypermethylation in oral tissues. Aberrant DNA hypermethylation is observed in oral inflammatory diseases, including chronic periodontitis, lichen planus, and radicular cysts.ConclusionSince epigenetic modifications are reversible, aberrant DNA methylation is a possible therapeutic target for such diseases. However, little is known about the epigenetics in oral inflammatory diseases, and further investigation is needed to elucidate the underlying mechanisms before epigenetic therapy can be used to treat oral inflammatory diseases.     

Acute and subacute pulmonary toxicity and mortality in mice after intratracheal instillation of ZnO nanoparticles in three laboratories

Inhalation is the main pathway of ZnO exposure in the occupational environment but only few studies have addressed toxic effects after pulmonary exposure to ZnO nanoparticles (NP). Here we present results from three studies of pulmonary exposure and toxicity of ZnO NP in mice. The studies were prematurely terminated because interim results unexpectedly showed severe pulmonary toxicity. High bolus doses of ZnO NP (25 up to 100 μg; ≥1.4 mg/kg) were clearly associated with a dose dependent mortality in the mice. Lower doses (≥6 μg; ≥0.3 mg/kg) elicited acute toxicity in terms of reduced weight gain, desquamation of epithelial cells with concomitantly increased barrier permeability of the alveolar/blood as well as DNA damage. Oxidative stress was shown via a strong increase in lipid peroxidation and reduced glutathione in the pulmonary tissue. Two months post-exposure revealed no obvious toxicity for 12.5 and 25 μg on a range of parameters. However, mice that survived a high dose (50 μg; 2.7 mg/kg) had an increased pulmonary collagen accumulation (fibrosis) at a similar level as a high bolus dose of crystalline silica. The recovery from these toxicological effects appeared dose-dependent. The results indicate that alveolar deposition of ZnO NP may cause significant adverse health effects.     

Tracking myeloma tumor DNA in peripheral blood

Over the past years, the emergence of liquid biopsy technologies has dramatically expanded our ability to assess multiple myeloma without the need for invasive sampling. Interrogation of cell-free DNA from the peripheral blood recapitulates the mutational landscape at excellent concordance with matching bone marrow aspirates. It can quantify disease burden and identify previously undetected resistance mechanisms which may inform clinical management in real-time. The convenience of sample acquisition and storage provides strong procedural benefits over currently available testing. Further investigations will have to define the role of cell-free DNA as a diagnostic measure by determining clinically relevant tumor thresholds in comparison to existing routine parameters. This review presents an overview of currently available assays and discusses the clinical value, potential and limitations of cell-free DNA technologies for the assessment of this challenging disease.     

A review of DNA profiling success for laser microdissected forensic casework samples

ABSTRACT

Laser microdissection (LMD) is a tool that is used in forensic laboratories for the analysis of DNA from specifically targeted cells. Since 2010, the Institute of Environmental Science and Research Limited’s (ESR) Forensic Biology laboratory has applied LMD DNA testing to a variety of sexual assault casework samples where small numbers of sperm are present in cell mixtures. In this paper we review the DNA profiling results obtained from semen-stained casework samples that have been analysed using the LMD DNA methodology developed in our laboratory. Dissected sperm have been analysed using the AmpFISTR Identifiler amplification kit at 28 cycle PCR, the AmpFISTR MiniFiler amplification kit at 30 cycle PCR, or the AmpFISTR SGM Plus amplification kit at 34 cycle PCR, depending on the number of sperm recovered and on consideration of other circumstantial case information, such as the time since intercourse (TSI). From a review of these data, success rates for different sample numbers of sperm recovered from semen-stained samples are determined. The DNA profiling results obtained from three cases where laser microdissection has been used are also presented to demonstrate the success of the LMD testing strategy in a forensic laboratory.     

First report of Mortierella wolfii causing fungal keratitis from a tertiary eye hospital in India

A young 33 year old male presented with non-resolving corneal infiltrate for 2 month duration in the right eye. KOH/ Calcoflour wet mount revealed sparsely septate fungal hyphae. Post therapeutic penetrating keratoplasty 3 doses of intracameral voriconazole(100μg/0.1ml) was administered suspecting recurrence. Fungal culture revealed non sporulating mould on SDA. PCR based DNA sequencing targeting the ITS region identified the fungal isolate as Mortierella wolfii (M. wolfii) belonging to zygomycetes. To the best of our knowledge, this is the first report of human fungal keratitis caused by M. wolfii.     

Human infections due to Schizophyllum commune: Case report and review of the literature

Schizophyllum commune is an environmental basidiomycetous fungus, causing occasional, predominantly respiratory, infections in humans. Although S. commune is considered an emerging pathogen, some authors pointed out the possibility that the increase in the diagnosed cases may be also due to recent advances in diagnostic technologies now allowing a more prompt and precise identification at the species level. Here we describe the first Italian case of chronic non-invasive fungal rhinosinusitis due to S. commune in an immunocompetent subject and update the literature review on S. commune sinusitis published between 2012–2019. A timely diagnosis is important to avoid local and systemic complications due to infection with this fungus. In our case, prompt identification at species level was only possible with the use of MALDI-TOF mass spectrometry and confirmed by sequence analysis of ribosomal DNA ITS regions, due to the difficulty in achieving a correct and rapid identification using routine morphological analysis.     

The circulating tumor DNA (ctDNA) alteration level predicts therapeutic response in metastatic breast cancer: Novel prognostic indexes based on ctDNA

PurposeCirculating tumor DNA (ctDNA) has good clinical guiding value for metastatic breast cancer (MBC) patients. This study aimed to apply a novel genetic analysis approach for therapeutic prediction based on ctDNA alterations.MethodThis nonrandomized, multicenter study recruited 223 MBC patients (NCT05079074). Plasma samples were collected for target-capture deep sequencing of ctDNA at baseline, after the 2nd cycle of treatment, and when progressive disease (PD) was evaluated. Samples were categorized into four levels according to the number of ctDNA alterations: level 1 (no alterations), level 2 (1–2 alterations), level 3 (3–4 alterations) and level 4 (≥5 alterations). According to ctDNA alteration level and variant allele frequency (VAF), a novel ctDNA-level Response Evaluation Criterion in Solid Tumors (ctle-RECIST) was established to assess treatment response and predict progression-free survival (PFS).ResultsThe median PFS in level 1 (6.63 months) patients was significantly longer than that in level 2–4 patients (level 2: 5.70 months; level 3–4: 4.90 months, p < 0.05). After 2 cycles of treatment, based on ctle-RECIST, the median PFS of level-based disease control rate (lev-DCR) patients was significantly longer than that of level-based PD (lev-PD) patients [HR 2.42 (1.52–3.85), p < 0.001]. In addition, we found that ctDNA level assessment could be a good supplement to radiologic assessment. The median PFS in the dual-DCR group tended to be longer than that in the single-DCR group [HR 1.41 (0.93–2.13), p = 0.107].ConclusionThe ctDNA alteration level and ctle-RECIST could be novel biomarkers of prognosis and could complement radiologic assessment in MBC.