Precision timing of PSR J1012+5307 and strong-field GR tests

We report on the high precision timing analysis of the pulsar-white dwarf binary PSR J1012+5307. Using 15 years of multi-telescope data from the European Pulsar Timing Array (EPTA) network, a significant measurement of the variation of the orbital period is obtained. Using this ideal strong-field gravity laboratory we derive theory independent limits for both the dipole radiation and the variation of the gravitational constant.Comment: 3 pages, Proceedings of the 12th Marcel Grossmann Meeting on General Relativity (MG 12

Effects of temperature and doxorubicin exposure on keratinocyte damage in vitro

Cancer chemotherapy treatment often leads to hair loss, which may be prevented by cooling the scalp during drug administration. The current hypothesis for the hair preservative effect of scalp cooling is that cooling of the scalp skin reduces blood flow (perfusion) and chemical reaction rates. Reduced perfusion leads to less drugs available for uptake, whereas the reduced temperature decreases uptake of and damage by chemotherapy. Altogether, less damage is exerted to the hair cells, and the hair is preserved. However, the two mechanisms in the hypothesis have not been quantified yet. To quantify the effect of reduced drug damage caused by falling temperatures, we investigated the effect of local drug concentration and local tissue temperature on hair cell damage using in vitro experiments on keratinocytes. Cells were exposed for 4 h to a wide range of doxorubicin concentrations. During exposure, cells were kept at different temperatures. Cell viability was determined after 3 d using a viability test. Control samples were used to establish a concentration–viability curve. Results show that cell survival is significantly higher in cooled cells (T < 22° C) than in non-cooled cells (T = 37° C), but no significant differences are visible between T = 10° C and T = 22° C. Based on this result and previous work, we can conclude that there is an optimal temperature in scalp cooling. Further cooling will only result in unnecessary discomfort for the patient and should therefore be avoided

Agonist signalling properties of radiotracers used for imaging of dopamine D-2/3 receptors

Background: Dopamine D-2/3 receptor (D2/3R) agonist radiopharmaceuticals are considered superior to antagonists to detect dopamine release, e.g. induced by amphetamines. Agonists bind preferentially to the high-affinity state of the dopamine D2R, which has been proposed as the reason why agonists are more sensitive to detect dopamine release than antagonist radiopharmaceuticals, but this theory has been challenged. Interestingly, not all agonists similarly activate the classic cyclic adenosine mono phosphate (cAMP) and the beta-arrestin-2 pathway, some stimulate preferentially one of these pathways; a phenomenon called biased agonism. Because these pathways can be affected separately by pathologies or drugs (including dopamine releasers), it is important to know how agonist radiotracers act on these pathways. Therefore, we characterized the intracellular signalling of the well-known D2/3R agonist radiopharmaceuticals NPA and PHNO and of several novel D2/3R agonists. Methods: cAMP accumulation and beta-arrestin-2 recruitment were measured on cells expressing human D2R. Results: All tested agonists showed (almost) full agonism in both pathways. Conclusions: The tested D2/3R agonist radiopharmaceuticals did not exhibit biased agonism in vitro. Consequently, it is likely that drugs (including psychostimulants like amphetamines) and/or pathologies that influence the cAMP and/or the beta-arrestin-2 pathway may influence the binding of these radiopharmaceuticals

Synthesis and In Vitro Evaluation of Novel Nortropane Derivatives as Potential Radiotracers for Muscarinic M2 Receptors

Disturbances of the cerebral cholinergic neurotransmitter system are present in neurodegenerative disorders. SPECT or PET imaging, using radiotracers that selectively target muscarinic receptor subtypes, may be of value for in vivo evaluation of such conditions. 6β-acetoxynortropane, a potent muscarinic M2 receptor agonist, has previously demonstrated nanomolar affinity and high selectivity for this receptor. Based on this compound we synthesized four nortropane derivatives that are potentially suitable for SPECT imaging of the M2 receptor. 6β-acetoxynortropane and the novel derivatives were tested in vitro for affinity to the muscarinic M1−3 receptors. The original 6β-acetoxynortropane displayed high affinity (Ki = 70–90 nM) to M2 receptors and showed good selectivity ratios to the M1 (65-fold ratio) and the M3 (70-fold ratio) receptors. All new derivatives showed reduced affinity to the M2 subtype and loss of subtype selectivity. It is therefore concluded that the newly synthesized derivatives are not suitable for human SPECT imaging of M2 receptors

No Excess Mortality in Patients Aged 50 Years and Older Who Received Treatment for Ductal Carcinoma In Situ of the Breast

Background. The incidence of ductal carcinoma in situ (DCIS) has increased at a fast rate.The aim of this study was to assess the incidence and treatment in the Netherlands and estimate the excess mortality risk of DCIS. Methods. From the Netherlands Cancer Registry, adult female patients (diagnosed 1997–2005) with DCIS were selected. Treatment was described according to age. Relative mortality at 10 years of follow-up was calculated by dividing observed mortality over expected mortality. Expected mortality was calculated using the matched Dutch general population. Results. Overall, 8421 patients were included in this study. For patients aged 50–64, and 65–74 an increase in breast-conserving surgery was observed over time (P < 0.001). For patients over 75 years of age, 8.0% did not undergo surgery; this percentage remained stable over time (P = 0.07). Overall, treated patients aged >50 years experienced no excess mortality regardless of treatment (relative mortality 1.0). Conclusion. The present population-based study of almost 8500 patients showed no excess mortality in surgically treated women over 50 years with DCIS

Reduced Vitamin K Status as a Potentially Modifiable Risk Factor of Severe Coronavirus Disease 2019

BACKGROUND: Respiratory failure and thromboembolism are frequent in SARS-CoV-2-infected patients. Vitamin K activates both hepatic coagulation factors and extrahepatic endothelial anticoagulant protein S, required for thrombosis prevention. In times of vitamin K insufficiency, hepatic procoagulant factors are preferentially activated over extrahepatic proteins. Vitamin K also activates matrix Gla protein (MGP), which protects against pulmonary and vascular elastic fiber damage. We hypothesized that vitamin K may be implicated in coronavirus disease 2019 (COVID-19), linking pulmonary and thromboembolic disease. METHODS: 135 hospitalized COVID-19 patients were compared with 184 historical controls. Poor outcome was defined as invasive ventilation and/or death. Inactive vitamin K-dependent MGP (dp-ucMGP) and prothrombin (PIVKA-II) were measured, inversely related to extrahepatic and hepatic vitamin K status, respectively. Desmosine was measured to quantify the rate of elastic fiber degradation. Arterial calcification severity was assessed by computed tomography. RESULTS: Dp-ucMGP was elevated in COVID-19 patients compared to controls (p<0.001), with even higher dp-ucMGP in patients with poor outcomes (p<0.001). PIVKA-II was normal in 82.1% of patients. Dp-ucMGP was correlated with desmosine (p<0.001), and coronary artery (p=0.002) and thoracic aortic (p<0.001) calcification scores. CONCLUSIONS: Dp-ucMGP was severely increased in COVID-19 patients, indicating extrahepatic vitamin K insufficiency, which was related to poor outcome while hepatic procoagulant factor II remained unaffected. These data suggest a mechanism of pneumonia-induced extrahepatic vitamin K depletion leading to accelerated elastic fiber damage and thrombosis in severe COVID-19 due to impaired activation of MGP and endothelial protein S, respectively. A clinical trial could assess whether vitamin K administration improves COVID-19 outcomes

Dynamics of Transcription Regulation in Human Bone Marrow Myeloid Differentiation to Mature Blood Neutrophils.

Neutrophils are short-lived blood cells that play a critical role in host defense against infections. To better comprehend neutrophil functions and their regulation, we provide a complete epigenetic overview, assessing important functional features of their differentiation stages from bone marrow-residing progenitors to mature circulating cells. Integration of chromatin modifications, methylation, and transcriptome dynamics reveals an enforced regulation of differentiation, for cellular functions such as release of proteases, respiratory burst, cell cycle regulation, and apoptosis. We observe an early establishment of the cytotoxic capability, while the signaling components that activate these antimicrobial mechanisms are transcribed at later stages, outside the bone marrow, thus preventing toxic effects in the bone marrow niche. Altogether, these data reveal how the developmental dynamics of the chromatin landscape orchestrate the daily production of a large number of neutrophils required for innate host defense and provide a comprehensive overview of differentiating human neutrophils

Dysregulated innate and adaptive immune responses discriminate disease severity in COVID-19

The clinical spectrum of COVID-19 varies and the differences in host response characterizing this variation have not been fully elucidated. COVID-19 disease severity correlates with an excessive pro-inflammatory immune response and profound lymphopenia. Inflammatory responses according to disease severity were explored by plasma cytokine measurements and proteomics analysis in 147 COVID-19 patients. Furthermore, peripheral blood mononuclear cell cytokine production assays and whole blood flow cytometry were performed. Results confirm a hyperinflammatory innate immune state, while highlighting hepatocyte growth factor and stem cell factor as potential biomarkers for disease severity. Clustering analysis reveals no specific inflammatory endotypes in COVID-19 patients. Functional assays reveal abrogated adaptive cytokine production (interferon-gamma, interleukin-17 and interleukin-22) and prominent T cell exhaustion in critically ill patients, whereas innate immune responses were intact or hyperresponsive. Collectively, this extensive analysis provides a comprehensive insight into the pathobiology of severe to critical COVID-19 and highlight potential biomarkers of disease severity