Alternative detection of SARS-CoV-2 RNA by a new assay based on mass spectrometry

OBJECTIVES

Accurate detection of SARS-CoV-2 RNA is essential to stopping the spread of SARS-CoV-2. The aim of this study was to evaluate the performance of the recently introduced MassARRAY^® SARS-CoV-2 Panel and to compare it to the cobas^® SARS-CoV-2 Test.

METHODS

The MassARRAY^® SARS-CoV-2 Panel consists of five assays targeting different sequences of the SARS-CoV-2 genome. Accuracy was determined using national and international proficiency panels including 27 samples. For clinical evaluation, 101 residual clinical samples were analyzed and results compared. Samples had been tested for SARS-CoV-2 RNA with the cobas^® SARS-CoV-2 Test.

RESULTS

When accuracy was tested with the MassARRAY^® SARS-CoV-2 Panel, 25 of 27 (92.6%) samples revealed correct results. When clinical samples were analyzed with the MassARRAY^® SARS-CoV-2 Panel and compared to the cobas^® SARS-CoV-2 Test, 100 samples showed concordant results. One sample was found to be inconclusive with the MassARRAY^® SARS-CoV-2 Panel. When time-to-results were compared, the new assay showed longer total and hands-on times.

CONCLUSIONS

The MassARRAY^® SARS-CoV-2 Panel showed a good performance and proved to be suitable for use in the routine diagnostic laboratory. Especially during phases of shortage of reagents and/or disposables, the new test system appears as beneficial alternative to standard assays used for detection of SARS-CoV-2 RNA.

Effect of cachexia on bone turnover in cancer patients: a case-control study

Background

Increased bone turnover is frequently observed in advanced cancer and predominantly related to bone metastases or therapy. Cachexia represents an important cause of morbidity and mortality in cancer patients. Key features are weight loss, muscle wasting and chronic inflammation, which induce profound metabolic changes in several organs, including the bone. However, whether cachexia contributes to abnormal bone metabolism in cancer patients is unknown. Aim of the present study was to determine the potential correlation of bone turnover markers with body composition and laboratory parameters in treatment-naïve cancer patients.

Methods

In this cross-sectional study we measured the levels of carboxy terminal telopeptide of collagen (CTX), an indicator of bone resorption, as well as osteocalcin (Ocn) and procollagen type I N-terminal propeptide (PINP), indicators of bone formation, in 52 cancer patients and correlated with body composition and laboratory parameters. Univariate and multivariate logistic analysis were performed to identify determinants of negative bone remodeling balance, estimated by CTX/Ocn and CTX/PINP ratio.

Results

Based on weight loss, body mass index and muscle mass, patients were divided into a cachectic (59.6%) and a control (40.4%) group. After correcting for the presence of bone metastases, our results showed a significant upregulation of CTX in cachectic patients compared to non-cachectic cancer patients (median 0.38 vs 0.27 ng/mL, p < 0.05), with no difference in Ocn and PINP levels (mean 14 vs. 16 ng/ml, p = 0.2 and median 32 vs. 26 μg/L, p = 0.5, respectively). In addition, the CTX/Ocn and the CTX/PINP ratio were indicative of bone resorption in 68% and 60% of cachexia patients, respectively (vs. 20% and 31% in the control group, p = 0.002 and p = 0.06). The main determinants of the unbalanced bone turnover were hypoalbuminemia for the CTX/Ocn ratio (OR 19.8, p < 0.01) and high CRP for the CTX/PINP ratio (OR 5.3, p < 0.01) in the multivariate regression analysis.

Conclusions

CTX is substantially higher in cachectic patients compared to non-cachectic oncological patients and hypoalbuminemia as well as elevated CRP concentrations are independent predictors of a negative bone remodeling balance in cancer patients. These results strongly indicate that cachexia correlates with exacerbated bone turnover in cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08518-9.

Sensitivity and specificity of cerebrospinal fluid CXCL13 for diagnosing Lyme neuroborreliosis - a study on 1410 patients and review of the literature

INTRODUCTION

The B-cell chemoattractant CXCL13 has been suggested as a cerebrospinal fluid (CSF) biomarker for Lyme neuroborreliosis (LNB). Our aim was to substantiate the value of CXCL13 in a large unselected cohort and determine a practical cut-off value to diagnose LNB.

METHODS

We retrospectively studied clinical and CSF data of consecutive patients who underwent CSF CXCL13 testing over a period of three years (February 2015 to January 2018) at our academic teaching hospital. Patients were classified into 12 groups according to their final diagnosis. To diagnose LNB (definite or probable/possible), definitions of the respective guideline of the German Neurological Society were applied.

RESULTS

Of 1410 patients, 29 were diagnosed with definite LNB and 9 with probable/possible LNB. Median CXCL13 levels were highly elevated in both LNB groups (554 pg/mL and 649 pg/mL, respectively) and the group with bacterial/fungal CNS infections (410 pg/mL; n = 6), while all other groups had markedly lower median CXCL13 levels (p < .001). For definite LNB, the best CXCL13 test cut-off was 55.5 pg/mL with a sensitivity of 96.6% (95% confidence interval, CI, 80.4%-99.8%) and a specificity of 94.9% (95% CI 93.5%-95.9%). All patients with LNB showed clinical improvement after antibiotic treatment.

CONCLUSION

In this large monocentric cohort, CSF CXCL13 was found to be a highly sensitive and useful marker for LNB. In conditions with low index of suspicion for LNB, CXCL13 testing may be unwarranted. A review of the literature on the sensitivity and specificity of CSF CXCL13 in the differential of LNB is provided.

Combined testing of copeptin and high-sensitivity cardiac troponin T at presentation in comparison to other algorithms for rapid rule-out of acute myocardial infarction

BACKGROUND

We aimed to directly compare the diagnostic and prognostic performance of a dual maker strategy (DMS) with combined testing of copeptin and high-sensitivity (hs) cardiac troponin T (cTnT) at time of presentation with other algorithms for rapid rule-out of acute myocardial infarction (AMI).

METHODS

922 patients presenting to the emergency department with suspected AMI and available baseline copeptin measurements qualified for the present TRAPID-AMI substudy. Diagnostic measures using the DMS (copeptin <10, <14 or < 20 pmol/L and hs-cTnT≤14 ng/L), the 1 h-algorithm (hs-cTnT<12 ng/L and change <3 ng/L at 1 h), as well as the hs-cTnT limit-of-blank (LoB, <3 ng/L) and -detection (LoD, <5 ng/L) were compared. Outcomes were assessed as combined end-points of death and myocardial re-infarction.

RESULTS

True-negative rule-out using the DMS could be achieved in 50.9%-62.3% of all patients compared to 35.0%, 45.3% and 64.5% using LoB, LoD or the 1 h-algorithm, respectively. The DMS showed NPVs of 98.1%-98.3% compared to 99.2% for the 1 h-algorithm, 99.4% for the LoB and 99.3% for the LoD. Sensitivities were 93.5%-94.8%, as well as 96.8%, 98.7% and 98.1%, respectively. Addition of clinical low-risk criteria such as a HEART-score ≤ 3 to the DMS resulted in NPVs and sensitivities of 100% with a true-negative rule-out to 33.8%-41.6%. Rates of the combined end-point of death/MI within 30 days ranged between 0.2% and 0.3% for all fast-rule-out protocols.

CONCLUSION

Depending on the applied copeptin cut-off and addition of clinical low-risk criteria, the DMS might be an alternative to the hs-cTn-only-based algorithms for rapid AMI rule-out with comparable diagnostic measures and outcomes.

Milk composition of captive vervet monkey (Chlorocebus pygerythrus) and rhesus macaque (Macaca mulatta) with observations on gorilla (Gorilla gorilla gorilla) and white handed gibbon (Hylobates lar)

The nutrient content and fatty acid composition of vervet monkey milk has been determined and is compared with rhesus macaque, and two hominoid apes, the white handed gibbon and gorilla. With 15.7+/-4.1 g protein, 33.1+/-9.4 g fat, and 85.1+/-7.5 g lactose per kg milk, vervet monkey milk does not differ from that of rhesus macaque, and is within the range of other primates. Small amounts (>1 g kg(-1)) of oligosaccharides, glucose, galactose and fucose were noted. In comparison, gorilla milk has a low fat content of 13.8 g kg(-1), but contains high levels of oligosaccharides at 7.0 g kg(-1) milk. The hominoid partner, the white handed gibbon, contains no oligosaccharides and a milk fat content similar to other hominoid species. Differences between vervet monkey and rhesus macaque milks were observed in the electrophoretic pattern of the milk proteins, mainly amongst the kappa- and gamma-caseins, which also differ from that of the hominids. The fatty acid contents of these milks differ from studies where a natural diet of leafy material was available in that a low content of alpha-linolenic acid (18:3n-3) was noted. A phylogenetic effect is observed for the content of 8:0, 10:0 fatty acids between the Cercopithecidae and Hominoidea, and a further phylogenetic effect suggested between the Hylobatidae and Hominidae.

Influence of cardiopulmonary resuscitation on levels of tumour markers

Tumour markers (TM), including alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen (CA) 15-3 and prostate-specific antigen (PSA), are serum markers for malignant diseases. Previous studies investigating the effect of acute and chronic inflammation, cardiopulmonary bypass surgery and cardiopulmonary resuscitation (CPR) on levels of TM showed conflicting results. Cardiopulmonary resuscitation (CPR) may result in a profound inflammatory response, and is frequently associated with severe tissue hypoperfusion. The present study investigated whether AFP, CEA, CA 15-3 and PSA are influenced by CPR. Alpha-fetoprotein (AFP), CEA, CA 15-3 and PSA (only in male patients) were assessed immediately after hospital admission, 6 h, 12 h and 2 days after prolonged CPR in eight male and 12 female patients. Serum levels of AFP, CEA, CA 15-3 did not change significantly after CPR. Prostate-specific antigen (PSA) levels increased significantly with a highest level in the study period 48 h after CPR (3.3 +/- 3.1 and 28.3 +/- 30.5 ng/mL for baseline and 48 h levels, respectively; P < 0.001). Alpha-fetoprotein (AFP), CEA, CA 15-3 and PSA (in men) values above the normal range were observed in 0%, 13.8%, 3.8% and 46.9% of all measurements respectively. At least one value above the normal range were observed in 0%, 20%, 5% and 75% of all patients for AFP, CEA, CA 15-3 and PSA (in men) respectively. Baseline values of AFP, CEA, CA 15-3 and PSA (in men) were above the normal range in 0%, 15%, 5% and 10% of all patients respectively. Levels for all markers did not differ significantly between survivors and non-survivors. In conclusion, prolonged CPR does not influence AFP, CEA, CA 15-3 serum levels, but is frequently associated with increases of PSA. Thus, in contrast to PSA, interpretation of AFP, CEA, CA 15-3 serum levels is not influenced by recent CPR.

The effect of diet on the Vervet monkey endocrine pancreas

Vervet monkeys (Cercopithecus aethiops) used for pancreatic endocrine cell distribution studies were found to have been maintained on different diets. Although the effect of dietary changes on the exocrine pancreas has been described in several animals, little, apart from the effect of malnutrition, has been reported for the endocrine pancreas. Reported here are pancreatic endocrine cell distributions in monkeys on a standard diet (n = 3) compared with monkeys on an atherogenic diet (n = 3). Quantitation of immunolabelled pancreatic endocrine cell types revealed a significant 80% increase in A (glucagon) cell volume in monkeys on an atherogenic diet concomitant with a significant reduction in B (insulin) cell volume to approximately 60% of normal. This reflects a pattern of events that occurs in non-insulin dependent diabetes. An accompanying reduction in PP (pancreatic polypeptide) cell volumes supports our hypothesis that altering A and PP cell volumes could reflect differential gene expression in those cells in the adult in which glucagon and PP are co-localized.