Identification of a novel coronavirus in patients with severe acute respiratory syndrome

BACKGROUND: The severe acute respiratory syndrome (SARS) has recently been identified as a new clinical entity. SARS is thought to be caused by an unknown infectious agent. METHODS: Clinical specimens from patients with SARS were searched for unknown viruses with the use of cell cultures and molecular techniques. RESULTS: A novel coronavirus was identified in patients with SARS. The virus was isolated in cell culture, and a sequence 300 nucleotides in length was obtained by a polymerase-chain-reaction (PCR)-based random-amplification procedure. Genetic characterization indicated that the virus is only distantly related to known coronaviruses (identical in 50 to 60 percent of the nucleotide sequence). On the basis of the obtained sequence, conventional and real-time PCR assays for specific and sensitive detection of the novel virus were established. Virus was detected in a variety of clinical specimens from patients with SARS but not in controls. High concentrations of viral RNA of up to 100 million molecules per milliliter were found in sputum. Viral RNA was also detected at extremely low concentrations in plasma during the acute phase and in feces during the late convalescent phase. Infected patients showed seroconversion on the Vero cells in which the virus was isolated. CONCLUSIONS: The novel coronavirus might have a role

Venous thromboembolism in critically ill COVID-19 patients receiving prophylactic or therapeutic anticoagulation: a systematic review and meta-analysis

Many aspects of care such as management of hypercoagulable state in COVID-19 patients, especially those admitted to intensive care units is challenging in the rapidly evolving pandemic of novel coronavirus disease 2019 (COVID-19). We seek to systematically review the available evidence regarding the anticoagulation approach to prevent venous thromboembolism (VTE) among COVID-19 patients admitted to intensive care units. Electronic databases were searched for studies reporting venous thromboembolic events in patients admitted to the intensive care unit receiving any type of anticoagulation (prophylactic or therapeutic). The pooled prevalence (and 95% confidence interval [CI]) of VTE among patients receiving anticoagulant were calculated using the random-effects model. Subgroup pooled analyses were performed with studies reported prophylactic anticoagulation alone and with studies reported mixed prophylactic and therapeutic anticoagulation. We included twelve studies (8 Europe; 2 UK; 1 each from the US and China) in our systematic review and meta-analysis. All studies utilized LMWH or unfractionated heparin as their pharmacologic thromboprophylaxis, either prophylactic doses or therapeutic doses. Seven studies reported on the proportion of patients with the previous history of VTE (range 0–10%). The pooled prevalence of VTE among ICU patients receiving prophylactic or therapeutic anticoagulation across all studies was 31% (95% CI 20–43%). Subgroup pooled analysis limited to studies reported prophylactic anticoagulation alone and mixed (therapeutic and prophylactic anticoagulation) reported pooled prevalences of VTE of 38% (95% CI 10–70%) and 27% (95% CI 17–40%) respectively. With a high prevalence of thromboprophylaxis failure among COVID-19 patients admitted to intensive care units, individualised rather than protocolised VTE thromboprophylaxis would appear prudent at interim

Diagnosing Schistosomiasis by Detection of Cell-Free Parasite DNA in Human Plasma

Bilharzia (schistosomiasis) occurs in the tropics and subtropics and is one of the most important parasite diseases of humans. It is caused by flukes residing in the vessels of the gut or bladder, causing fever, pain, and bleeding. Bladder cancer or esophageal varices may follow. Diagnosis is difficult, requiring detection of parasite eggs in stool, urine, or gut/bladder biopsies. In this paper, we introduce a fundamentally new way of diagnosing bilharzia from the blood. It has been known for almost 20 years that patients with cancer have tumor-derived DNA circulating in their blood, which can be used for diagnostic purposes. During pregnancy, free DNA from the fetus can be detected in motherly blood, which can be used for diagnosing a range of fetal diseases and pregnancy-associated complications. We found that parasite DNA can be detected in the same way in the blood of patients with bilharzia. In patients with early disease, diagnosis was possible earlier than with any other test. DNA could be detected in all patients with active disease in our study. Patients after treatment had significantly lower parasite DNA concentrations and turned negative 1–2 years after treatment. Future studies should implement the method in large cohorts of patients and should define criteria for the confirmation of the success of treatment by comparing the concentration of fluke DNA before and after therapy

Improving perfusion quantification in arterial spin labeling for delayed arrival times by using optimized acquisition schemes

Ziel Bei Arterial-Spin-Labeling-(ASL)-Experimenten zerfällt die Markierung des Blutes mit T1. Durch Umverteilung der sonst gleich verteilten Mittelungen bei Experimenten mit verschiedenen Einströmzeiten (multi-TI) kann dem T1-induzierten Signalzerfall entgegengewirkt werden. Die Verbesserung der Perfusionsbestimmung gerade bei später Ankunft des markierten Blutes (bolus arrival time, BAT) wird untersucht. Material und Methoden Die multi-TI-3D-GRASE-Sequenz ist so angepasst, dass kurze Einströmzeiten weniger oft gemittelt werden als lange. Die gesamte Anzahl der Akquisitionen bleibt unverändert und damit auch die Messzeit konstant. Die hierdurch verbesserte Perfusionsbestimmung wird anhand von Simulationen, Messung gesunder Probanden und Patienten mit altersbedingt verlängerter BAT oder stenosierenden Verschlusserkrankungen evaluiert. Ergebnisse Mit unserem angepassten Akquisitionsschema zeigen sich für gesunde BATs keine Unterschiede in der Perfusionsbestimmung im Vergleich zum Standardverfahren mit gleich verteilten Mittelungen. Für BATs > 1500ms hingegen kann der Fehler in der Perfusionsbestimmung um 30% verringert werden. Schlussfolgerung Unser angepasstes Aufnahmeverfahren verbessert die Perfusionsbestimmung gerade bei langen BATs. Im klinischen Alltag ist nur eine multi-TI-Messung notwendig, da Ergebnisse im krankhaften BAT-Bereich verbessert werden, ohne diese im gesunden zu verschlechtern. Dies unterstreicht die hohe klinische Relevanz für die neurologische Bildgebung, insbesondere bei stenosierenden Verschlusserkrankungen

Comparison of methods for current-to-prior registration of breast DCE-MRI

The use of prior studies to complement the information in Breast Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) can help to reduce the currently high false positive ratios. Registration is a fundamental part of this process, as registration algorithms provide automatic correspondences between current and prior studies. The deformable nature of the breast and differences in acquisition protocols make this a particularly challenging problem. In this paper we study three registration algorithms (Affine, SyN and Demons) applied to DCE-MRI images obtained from clinical practice. The methodology followed for this study included using segmentation algorithms in order to focus on the area of the breast. Anatomical landmarks were also added by an expert for evaluation purposes. This allowed us to use an anatomical-landmark-based measure in order to evaluate the quality of registration. Additionally, an image metric was also used for the same purpose. Results, shown to be statistically significant indicate how SyN obtains the best results in terms of the two measures considered