Mitogenome sequences of domestic cats demonstrate lineage expansions and dynamic mutation processes in a mitochondrial minisatellite.

BACKGROUND: As a population genetic tool, mitochondrial DNA is commonly divided into the ~ 1-kb control region (CR), in which single nucleotide variant (SNV) diversity is relatively high, and the coding region, in which selective constraint is greater and diversity lower, but which provides an informative phylogeny. In some species, the CR contains variable tandemly repeated sequences that are understudied due to heteroplasmy. Domestic cats (Felis catus) have a recent origin and therefore traditional CR-based analysis of populations yields only a small number of haplotypes. RESULTS: To increase resolution we used Nanopore sequencing to analyse 119 cat mitogenomes via a long-amplicon approach. This greatly improves discrimination (from 15 to 87 distinct haplotypes in our dataset) and defines a phylogeny showing similar starlike topologies within all major clades (haplogroups), likely reflecting post-domestication expansion. We sequenced RS2, a CR tandem array of 80-bp repeat units, placing RS2 array structures within the phylogeny and increasing overall haplotype diversity. Repeat number varies between 3 and 12 (median: 4) with over 30 different repeat unit types differing largely by SNVs. Five SNVs show evidence of independent recurrence within the phylogeny, and seven are involved in at least 11 instances of rapid spread along repeat arrays within haplogroups. CONCLUSIONS: In defining mitogenome variation our study provides key information for the forensic genetic analysis of cat hair evidence, and for the first time a phylogenetically informed picture of tandem repeat variation that reveals remarkably dynamic mutation processes at work in the mitochondrion.

Defining cat mitogenome variation and accounting for numts via multiplex amplification and Nanopore sequencing.

Hair shed by domestic cats is a potentially useful source of forensic evidence. Analysable hair DNA is predominantly mitochondrial, but the recent domestication history of cats means that mtDNA diversity is low. A 402-bp control region segment is usually sequenced, defining only a small number of distinct haplotypes in populations. Previously, we used a long-amplicon approach to sequence whole mitogenomes in a sample of blood DNAs from 119 UK cats, greatly increasing observed diversity and reducing random match probabilities. To exploit this variation for forensic analysis, we here describe a multiplex system that amplifies the cat mitogenome in 60 overlapping amplicons of mean length 360 bp, followed by Nanopore sequencing. Variants detected in multiplex sequence data from unrooted hair completely mirror those from long-amplicon data from blood from the same individuals. However, applying the multiplex to matched blood DNA reveals additional sequence variants which derive from the major feline nuclear mitochondrial insertion sequence (numt), which covers 7.9 kb of the 17-kb mitogenome and exists in multiple tandem copies. We use long-amplicon Nanopore sequencing to investigate numt variation in a set of cats, together with an analysis of published genome sequences, and show that numt arrays are variable in both structure and sequence, thus providing a potential source of uncertainty when nuclear DNA predominates in a sample. Forensic application of the multiplex was demonstrated by matching hairs from a cat with skeletal remains from its putative mother, both of which shared a globally common haplotype at the control region. The random match probability in this case with the CR 402-bp segment was 0.21 and this decreased to 0.03 when considering the whole mitogenome. The developed multiplex and sequencing approach, when applied to cat hair where nuclear DNA is scarce, can provide a reliable and highly discriminating source of forensic genetic evidence from a single hair. The confounding effect of numt co-amplification in degraded samples where mixed sequences are observed can be mitigated by variant phasing, and by comparison with numt sequence diversity data, such as those presented here.

Management of patients with cervical spine trauma in the emergency department: a systematic critical appraisal of guidelines with a view to developing standardized strategies for clinical practice.

Several guidelines on the evaluation of patients with suspected cervical spine trauma in the Emergency Department (ED) exist. High heterogeneity between different guidelines has been reported. Aim of this study was to find areas of agreement and disagreement between guidelines, to identify topics in which further research is needed and to provide an evidence-based cervical spine trauma algorithm for ED physicians. The three most relevant guidelines published on cervical spine trauma in the last 10 years were selected screening websites of the main scientific societies and through the comparison of a normalized Google Scholar and SCOPUS citation index. We compared the selected guidelines through seven a-priori defined questions. In case of disagreement between the guidelines or if the quality of evidence appeared low, evidence from published systematic reviews on the topic was added to build an evidence-based algorithm for approach to spinal trauma in the ED. The three selected guidelines were: NICE 2016, Eastern Association for the Surgery of Trauma 2009 and American Association of Neurological Surgeons and Congress of Neurological Surgeons 2013. We found complete agreement on one question, partial agreement for one questions, no agreement for two questions, while agreement was not assessable for 3 questions. The agreement between different guidelines and the evidence on which recommendations are based is low. An attempt to build an evidence-based algorithm has been made. More studies are needed on many topics.

The Circulating Nucleic Acid Characteristics of Non-Metastatic Soft Tissue Sarcoma Patients.

Soft tissue sarcomas (STS) are rare, malignant tumours with a generally poor prognosis. Our aim was to explore the potential of cell free DNA (cfDNA) and circulating tumour DNA (ctDNA) analysis to track non-metastatic STS patients undergoing attempted curative treatment. The analysed cohort (n = 29) contained multiple STS subtypes including myxofibrosarcomas, undifferentiated pleomorphic sarcomas, leiomyosarcomas, and dedifferentiated liposarcomas amongst others. Perioperative cfDNA levels trended towards being elevated in patients (p = 0.07), although did not correlate with tumour size, grade, recurrence or subtype, suggesting a limited diagnostic or prognostic role. To characterise ctDNA, an amplicon panel covering three genes commonly mutated in STSs was first trialled on serial plasma collected from nine patients throughout follow-up. This approach only identified ctDNA in 2.5% (one in 40) of the analysed samples. Next custom-designed droplet digital PCR assays and Ion AmpliSeq™ panels were developed to track single nucleotide variants identified in patients' STSs by whole exome sequencing (1-6 per patient). These approaches identified ctDNA in 17% of patients. Although ctDNA was identified before radiologically detectable recurrence in two cases, the absence of demonstrable ctDNA in 83% of cases highlights the need for much work before circulating nucleic acids can become a useful means to track STS patients.

Longitudinal monitoring of circulating tumour DNA improves prognostication and relapse detection in gastroesophageal adenocarcinoma.

BACKGROUND: Gastroesophageal adenocarcinoma (GOA) has poor clinical outcomes and lacks reliable blood markers. Here we present circulating tumour DNA (ctDNA) as an emerging biomarker. METHODS: Forty patients (17 palliative and 23 curative) were followed by serial plasma monitoring. Primary tumour DNA was analysed by targeted next-generation sequencing to identify somatic single-nucleotide variants (SNVs), and Nanostring nCounter® to detect copy number alterations (CNAs). Patient-specific SNVs and CNA amplifications (CNAamp) were analysed in plasma using digital droplet PCR and quantitative PCR, respectively. RESULTS: Thirty-five patients (13 palliative, 22 curative) had ≥1 SNVs and/or CNAamp detected in primary tumour DNA suitable for tracking in plasma. Eighteen of 35 patients (nine palliative, nine curative) had ≥1 ctDNA-positive plasma sample. Detection of postoperative ctDNA predicted short RFS (190 vs 934 days, HR = 3.7, p = 0.028) and subsequent relapse (PPV for relapse 0.83). High ctDNA levels (>60.5 copies/ml) at diagnosis of metastatic disease predicted poor OS (90 vs 372 days, HR = 11.7 p < 0.001). CONCLUSION: Sensitive ctDNA detection allows disease monitoring and prediction of short OS in metastatic patients. Presence of ctDNA postoperatively predicts relapse and defines a 'molecular relapse' before overt clinical disease. This lead time defines a potential therapeutic window for additional anticancer therapy.

Multiple mutations at exon 2 of RHOA detected in plasma from patients with peripheral T-cell lymphoma.

The mutational landscape of peripheral T-cell lymphoma (PTCL) is being revealed through sequencing of lymph node samples, but there has been little work on the mutational load that is present in cell-free DNA (cfDNA) from plasma. We report targeted sequencing of cfDNA from PTCL patients to demonstrate c.50G>T (p.Gly17Val) in RHOA as previously described in angioimmunoblastic T-cell lymphoma (AITL) and a group of PTCL not otherwise specified (NOS) but also detect novel mutations at c.73A>G (p.Phe25Leu) and c.48A>T (p.Cys16*) of exon 2, which were confirmed by Sanger sequencing. In a group of AITL and PTCL-NOS analyzed by droplet digital polymerase chain reaction, 63% (12/19) showed c.50G>T (p.Gly17Val), 53% (10/19) c.73A>G (p.Phe25Leu), and 37% (7/19) c.48A>T (pCys16*). Sequencing of lymph node tissue in 3 out of 9 cases confirmed the presence of c.73A>G (p.Phe25Leu). Inspection of individual sequencing reads from individual patients showed that a single RHOA allele could contain >1 mutation, suggesting haplotypes of mutations at RHOA. Serial sampling showed changes to RHOA mutational frequency with treatment and the apparent occurrence of clones bearing specific haplotypes associated with relapse. Therefore, sequencing of RHOA from cfDNA has revealed new mutations and haplotypes. The clinical significance of these findings will need to be explored in clinical trials, but liquid biopsy might have potential for guiding treatment decisions in PTCL.

Need for Deprescribing in Hospital Elderly Patients Discharged with a Limited Life Expectancy: The REPOSI Study.

OBJECTIVE: Older people approaching the end of life are at a high risk for adverse drug reactions. Approaching the end of life should change the therapeutic aims, triggering a reduction in the number of drugs.The main aim of this study is to describe the preventive and symptomatic drug treatments prescribed to patients discharged with a limited life expectancy from internal medicine and geriatric wards. The secondary aim was to describe the potentially severe drug-drug interactions (DDI). MATERIALS AND METHODS: We analyzed Registry of Polytherapies Societa Italiana di Medicina Interna (REPOSI), a network of internal medicine and geriatric wards, to describe the drug therapy of patients discharged with a limited life expectancy. RESULTS: The study sample comprised 55 patients discharged with a limited life expectancy. Patients with at least 1 preventive medication that could be considered for deprescription at the end of life were significantly fewer from admission to discharge (n = 30; 54.5% vs. n = 21; 38.2%; p = 0.02). Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, lipid-lowering drugs, and clonidine were the most frequent potentially avoidable medications prescribed at discharge, followed by xanthine oxidase inhibitors and drugs to prevent fractures. Thirty-seven (67.3%) patients were also exposed to at least 1 potentially severe DDI at discharge. CONCLUSION: Hospital discharge is associated with a small reduction in the use of commonly prescribed preventive medications in patients discharged with a limited life expectancy. Cardiovascular drugs are the most frequent potentially avoidable preventive medications. A consensus framework or shared criteria for potentially inappropriate medication in elderly patients with limited life expectancy could be useful to further improve drug prescription.

Circulating tumour-derived DNA in metastatic soft tissue sarcoma.

Following treatment 40% of soft tissue sarcoma (STS) patients suffer disease recurrence. In certain cancers circulating cell free DNA (cfDNA) and circulating tumour-derived DNA (ctDNA) characteristics correlate closely with disease burden, making them exciting potential sources of biomarkers. Despite this, the circulating nucleic acid characteristics of only 2 STS patients have been reported to date. To address this we used an Ion AmpliSeq™ panel custom specifically designed for STS patients to conduct a genetic characterisation of plasma cfDNA, buffy coat (germline) DNA and where available Formalin-Fixed Paraffin-Embedded (FFPE) primary STS tissue DNA in a cohort of 11 metastatic STS patients. We found that total cfDNA levels were significantly elevated in the STS patients analysed, and weakly correlated with disease burden. Using our Ion AmpliSeq™ panel we also successfully detected ctDNA in 4/11 (36%) patients analysed with a wide variety of STS subtypes and disease burdens. This evidence included the presence of cancer associated TP53 / PIK3CA mutations in 2 patients' plasma and matched primary STS tumour tissue, and in the plasma alone for 2 patients. We also identified 2 potential examples of allelic loss of heterozygosity in an additional patient's STS DNA and cfDNA. This is the largest study performed characterising STS patient cfDNA/ctDNA and confirms that the field remains an attractive potential source of novel STS biomarkers. Further work is required to investigate the circulating nucleic acid characteristics of individual STS subtypes, and the potential prognostic or therapeutic roles that cfDNA/ctDNA may hold for patients with these complex tumours.

Telomere maintenance in soft tissue sarcomas.

Soft tissue sarcomas (STS) are a diverse group of heterogeneous malignant tumours derived from mesenchymal tissues. Over 50 different STS subtypes are recognised by WHO, which show a wide range of different biological behaviours and prognoses. At present, clinicians managing this complex group of tumours face several challenges. This is reflected by the relatively poor outcome of patients with STSs compared with many other solid malignant tumours. These include difficulties securing accurate diagnoses, a lack of effective systemic treatments and absence of any sensitive circulating biomarkers to monitor patients throughout their treatment and follow-up. In order to progress STS's cells must evade the usual cellular proliferative checkpoints, and then activate a telomere maintenance mechanism in order to achieve replicative immortality. The purpose of this review is to provide an overview of STS genetics focusing particularly on these mechanisms. We will also highlight some of the key barriers to improving outcome for patients with STS, and hypothesise how a better understanding of these genetic characteristics may impact on future STS management.

Application of a mitochondrial DNA control region frequency database for UK domestic cats.

DNA variation in 402bp of the mitochondrial control region flanked by repeat sequences RS2 and RS3 was evaluated by Sanger sequencing in 152 English domestic cats, in order to determine the significance of matching DNA sequences between hairs found with a victim's body and the suspect's pet cat. Whilst 95% of English cats possessed one of the twelve globally widespread mitotypes, four new variants were observed, the most common of which (2% frequency) was shared with the evidential samples. No significant difference in mitotype frequency was seen between 32 individuals from the locality of the crime and 120 additional cats from the rest of England, suggesting a lack of local population structure. However, significant differences were observed in comparison with frequencies in other countries, including the closely neighbouring Netherlands, highlighting the importance of appropriate genetic databases when determining the evidential significance of mitochondrial DNA evidence.

A Very Big Hand Is a Very Big Problem: Soft-Tissue Infection, Venous Thrombosis, or Just an Insect Sting?

A 67-year-old woman developed severe edema of her right hand and forearm, for which she was treated with antibiotics, without benefit. The echography excluded a venous thrombosis. Subsequently, she referred a wasp sting before the development of the edema. Specific Hymenoptera venom immunoglobulin E (IgE) was found to be positive for paper wasp and yellow jacket. A large local reaction (LLR) was diagnosed due to the hymenoptera sting. Self-injectable epinephrine was prescribed for possible, though unlikely, systemic reactions following hymenoptera stings. LEARNING POINTS: The differential diagnosis of an upper forearm and hand oedema may be challenging.In order to reach the correct diagnosis and to prescribe proper treatment, careful examination and history taking is essential.All possible causes should be taken into proper consideration.Large local reaction (LLR) is characterized by hot, flushed and thick edema after a hymenoptera sting. As the risk of a systemic reaction, upon the first sting following a consistent index LLR, it is important to recognize an LLR in order to prescribe self-injectable epinephrine to prevent the occurrence of anaphylaxis.

An evolutionary history of defensins: a role for copy number variation in maximizing host innate and adaptive immune responses.

Defensins represent an evolutionary ancient family of antimicrobial peptides that play diverse roles in human health and disease. Defensins are cationic cysteine-containing multifunctional peptides predominantly expressed by epithelial cells or neutrophils. Defensins play a key role in host innate immune responses to infection and, in addition to their classically described role as antimicrobial peptides, have also been implicated in immune modulation, fertility, development, and wound healing. Aberrant expression of defensins is important in a number of inflammatory diseases as well as modulating host immune responses to bacteria, unicellular pathogens, and viruses. In parallel with their role in immunity, in other species, defensins have evolved alternative functions, including the control of coat color in dogs. Defensin genes reside in complex genomic regions that are prone to structural variations and some defensin family members exhibit copy number variation (CNV). Structural variations have mediated, and continue to influence, the diversification and expression of defensin family members. This review highlights the work currently being done to better understand the genomic architecture of the ß-defensin locus. It evaluates current evidence linking defensin CNV to autoimmune disease (i.e., Crohn's disease and psoriasis) as well as the contribution CNV has in influencing immune responses to HIV infection.

Evidence of convergent evolution in humans and macaques supports an adaptive role for copy number variation of the ß-defensin-2 gene.

ß-defensins are a family of important peptides of innate immunity, involved in host defense, immunomodulation, reproduction, and pigmentation. Genes encoding ß-defensins show evidence of birth-and-death evolution, adaptation by amino acid sequence changes, and extensive copy number variation (CNV) within humans and other species. The role of CNV in the adaptation of ß-defensins to new functions remains unclear, as does the adaptive role of CNV in general. Here, we fine-map CNV of a cluster of ß-defensins in humans and rhesus macaques. Remarkably, we found that the structure of the CNV is different between primates, with distinct mutational origins and CNV boundaries defined by retroviral long terminal repeat elements. Although the human ß-defensin CNV region is 322 kb and encompasses several genes, including ß-defensins, a long noncoding RNA gene, and testes-specific zinc-finger transcription factors, the orthologous region in the rhesus macaque shows CNV of a 20-kb region, containing only a single gene, the ortholog of the human ß-defensin-2 gene. Despite its independent origins, the range of gene copy numbers in the rhesus macaque is similar to humans. In addition, the rhesus macaque gene has been subject to divergent positive selection at the amino acid level following its initial duplication event between 3 and 9.5 Ma, suggesting adaptation of this gene as the macaque successfully colonized novel environments outside Africa. Therefore, the molecular phenotype of ß-defensin-2 CNV has undergone convergent evolution, and this gene shows evidence of adaptation at the amino acid level in rhesus macaques.