Asymptomatic COVID-19: What the Neuroradiologist Needs to Know about Pulmonary Manifestations.

Coronavirus disease 2019 (COVID-19) is an infectious disease with a high asymptomatic incidence. Asymptomatic infections within a population will inevitably lead to diagnosis via unrelated medical imaging. We report the case of an asymptomatic patient undergoing a spine CT examination for trauma who was incidentally found to have lung abnormalities later confirmed to be COVID-19. We aim to familiarize neuroradiologists with the spectrum of COVID-19 pulmonary manifestations that are likely to be observed on neck and spine CT imaging.

Radiation exposure of adrenal vein sampling: a German Multicenter Study

Objective: Adrenal vein sampling (AVS) represents the current diagnostic standard for subtype differentiation in primary aldosteronism (PA). However, AVS has its drawbacks. It is invasive, expensive, requires an experienced interventional radiologist and comes with radiation exposure. However, exact radiation exposure of patients undergoing AVS has never been examined. Design and Methods: We retrospectively analyzed radiation exposure of 656 AVS performed between 1999 and 2017 at four university hospitals. The primary outcomes were dose area product (DAP) and fluoroscopy time (FT). Consecutively the effective dose (ED) was approximately calculated. Results: Median DAP was found to be 32.5 Gy*cm2 (0.3­3181) and FT 18 min (0.3­184). The calculated ED was 6.4 mSv (0.1­636). Remarkably, values between participating centers highly varied: Median DAP ranged from 16 to 147 Gy*cm2, FT from 16 to 27 min, and ED from 3.2 to 29 mSv. As main reason for this variation, differences regarding AVS protocols between centers could be identified, such as number of sampling locations, frames per second and the use of digital subtraction angiographies. Conclusions: This first systematic assessment of radiation exposure in AVS not only shows fairly high values for patients, but also states notable differences among the centers. Thus, we not only recommend taking into account the risk of radiation exposure, when referring patients to undergo AVS, but also to establish improved standard operating procedures to prevent unnecessary radiation exposure.

Prevalence of Malignancies in Patients With Primary Aldosteronism.

CONTEXT: Primary aldosteronism (PA) is the most common cause of secondary hypertension. Aldosterone excess can cause DNA damage in vitro and in vivo. Single case reports have indicated a coincidence of PA with renal cell carcinoma and other tumors. However, the prevalence of benign and malignant neoplasms in patients with PA has not yet been studied. PATIENTS AND DESIGN: In the multicenter MEPHISTO study, the prevalence of benign and malignant tumors was investigated in 335 patients with confirmed PA. Matched hypertensive subjects from the population-based Study of Health in Pomerania cohort served as controls. RESULTS: Of the 335 PA patients, 119 (35.5%) had been diagnosed with a tumor at any time, and 30 had two or more neoplasms. Lifetime malignancy occurrence was reported in 9.6% of PA patients compared to 6.0% of hypertensive controls (P = .08). PA patients with a history of malignancy had higher baseline aldosterone levels at diagnosis of PA (P = .009), and a strong association between aldosterone levels and the prevalence of malignancies was observed (P = .03). In total, 157 neoplasms were identified in the PA patients; they were benign in 61% and malignant in 25% of the cases (14% of unknown dignity). Renal cell carcinoma was diagnosed in five patients (13% of all malignancies) and was not reported in controls CONCLUSION: Compared to hypertensive controls, the prevalence of malignancies was positively correlated with aldosterone levels, tended to be higher in PA patients, but did not differ significantly.

Research and development of functional aids.

Four aids, developed by the Department for Research and Development from existing ideas and being used in Revalidatiecentrum "De Hoogstraat" by patients with a spinal cord injury, are described. These aids are: a dynamic elbow extension orthosis; a modified flexor hinge splint; a rolling writing aid, and a urinary device for females.

A comparison of the uptake of [75Se]selenite, [75Se]selenomethionine and [35S]methionine by tissues of ewes and lambs.

The fate of selenium, given as Na2(75)SeO3, or [75Se]selenomethionine, and of [35S]methionine administered intravenously to ewes and lambs, has been examined. The main intention was to follow the incorporation of selenium into protein in a number of tissues, including liver and kidney, and to measure the extent of that incorporation of selenoamino acid, particularly with respect to the administration of selenite. The ewes chosen were lactating ewes with lambs at foot, and the lambs were animals which had been weaned on to fodder low in selenium and were recovering from white muscle disease with selenium therapy. These two experimental situations were chosen as they offered conditions under which selenium incorporation might be considered to be maximal. Entry of isotope into milk was rapid and was greater when 75Se was given as the selenoamino acid than as selenite. In both ewes and lambs greater amounts of activity, derived from selenite, were bound to plasma proteins than to the proteins of milk. This was particularly evident in samples taken some hours after administration. This ability of the plasma to bind selenium was demonstrated by alkaline dialysis. Small, though significant amounts of selenium, derived from Na2(75)SeO3, were incorporated as selenoamino acids into the proteins of liver, kidney and pancreas, as well as into the proteins of milk and plasma. In ewes, both selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney. Some differences occurred in the distribution of labelled compounds in organs from lactating ewes and recovering lambs. The incorporation of selenium into protein is discussed briefly in relation to the recent findings of an association between selenium and the enzyme glutathione peroxidase.

PIP: A comparison of the uptake of selenium (Se) 75 selenite, Se 75 selen omethionine and Se 75 methionine by tissues of ewes and lambs is presented. Included in the study were 3 lactating ewes with lambs at foot and 3 lambs which had been weaned on to fodder low in selenium and were recovering from white muscle disease with Se therapy. Isotope entry into milk was rapid and was greater when Se 75 was administered as selenoamino acid than as selenite. Alkaline dialysis demonstrated that greater amounts of activity derived from selenite were bound to plasma proteins than to the protein of milk, particularly in samples taken some hours after administration. Small amounts of Se 75 selenomethionine were incorporated as selenoamino acids into the proteins of liver, kidney, pancreas, milk and plasma. Selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney of the ewes. Some differences were seen in the distribution of labelled compounds in organs from the ewes and lambs. Recent findings of an association between selenium and glutathione peroxidase are discussed in relation to the incorporation of selenium into protein.

Retention of 45Ca in rats and lambs associated with the onset of nutritional muscular dystrophy.

Nutritional myopathy has been induced in both rats and lambs by feeding diets low in selenium. The distribution of 45Ca, administered as 45CaCl2, has been examined firstly by autoradiography, and secondly by measuring the excretion of 45Ca in urine and faeces. Autoradiographs of skeletal muscle from unsupplemented animals showed radioactivity over discrete muscle fibres at a stage when no abnormalities were apparent using conventional staining techniques. Similar retention of 45Ca was found in some of the tubules in the kidneys of selenium-deficient rats. Total excretion in urine and faeces of lambs, examined for 48 h after intravenous administration of 45CaCl2, showed that in normal animals 18-6% of the dose was excreted, whereas in dystrophic lambs 12-0% was lost. The difference was significant at the 2% level. The respiratory rates of isolated skeletal muscle mitochondria, measured polarographically in the presence of glutamate and pyruvate as substrates, were low for dystrophic rats. Respiratory control indices were 1-0 for the same preparations but for supplemented rats they were all above 1-0. The differences in respiratory rates were significant at the 1% level. The major conclusion drawn from the results of these experiments is that one of the first effects of sleenium deficiency which can be visualized is the abnormal retention of calcium by individual muscle fibres.

Glutathione peroxidase activities in sheep and rat muscle and some effects of selenium deficiency.

The activity and distribution of the selenium-containing enzyme, glutathione peroxidase, has been determined in muscle fractions in normal adult rats and sheep. Skeletal and cardiac muscle have been examined, and in both types of muscle the major proportion of the enzyme appeared in the cytosol fraction. Enzyme activity was higher in cardiac muscle than in skeletal muscle in both species, and based on total protein present in fractions, it appears that rat muscle contains more enzyme activity than sheep muscle. In tissues from lambs born to selenium-deprived ewes the levels of enzyme were significantly depressed. Two sampling periods were selected, the first when the lambs were 2-3 weeks of age and the second at slaughter when they were 10 weeks old. Muscle, plasma and erythrocyte levels of the enzyme indicated that the most sensitive measure of selenium deficiency is likely to be that of the erythrocyte enzyme level.

Fibrinogen: structure, function, and surface interactions.

Fibrinogen plays a central role in the mechanism of coagulation and thrombosis and is partially involved in the development of postintervention restenosis. Because of therapeutic implications, it is convenient for the vascular interventionalist to revisit its structure, function, and relationships within the vascular environment. This review focuses on the molecular structure, mechanisms of polymerization and lysis, and fibrinogen interaction with the platelet alpha(IIb)beta(3) [corrected] integrin. It also addresses the less understood interaction of fibrinogen with artificial surfaces. Glycoprotein IIb-IIIa blockers, targeted to interfere with fibrinogen-platelet interactions, widely used in clinical practice, are discussed, and trials of new drugs are also summarized.

Influence of stent edge angle on endothelialization in an in vitro model.

PURPOSE: To investigate the influence of topographic features in the path of migrating endothelial cells, specifically the effect of edge angle of intravascular metallic material on endothelialization. MATERIALS AND METHODS: Flat 1-cm x 1-cm 316-L pieces of stainless steel were placed on confluent monolayers of human aortic endothelial cells. The thickness of each metal piece was ground to achieve an edge angle of 35 degrees, 70 degrees, 90 degrees, or 140 degrees (n = 6 each) in relation to the endothelial surface. Migration distance and density of endothelial cell coverage on the metal pieces were measured in groups of six each under static conditions at 4, 7, and 11 days and flow conditions (16 dynes/cm(2)) at 4 days. RESULTS: Endothelial cell migration distance along the surface of the pieces with edge angles of 35 degrees was significantly greater than that with those with larger angles (P < .05) under static and flow conditions. The migration distances on the 35 degrees piece were 87.5%, 47.3%, 57.1%, and 66.1% greater than those on the 90 degrees piece at the upstream, downstream, right, and left edges, respectively. There were no significant differences in cell density among different angle groups under flow or static conditions. CONCLUSION: The edge angle of intravascular metallic material has an influence on the rate of endothelialization. A smaller edge angle facilitates endothelialization over metallic material when compared to a larger angle. These results demonstrate the importance of metallic stent profile on endothelialization rate.

Natural protein variants of pregnane X receptor with altered transactivation activity toward CYP3A4.

Between 45 and 60% of all drugs currently used are metabolized by the CYP3A4 protein. CYP3A4 expression in liver varies up to 60-fold in the general population, which can lead to ineffective drug therapy (high CYP3A4) or, on the other hand, to harmful drug reactions (low CYP3A4). Most of this variability has been attributed to genetic factors, but to date their identity remains unknown. Recently, it was shown that CYP3A expression is largely controlled by the pregnane X receptor (PXR). We, therefore, hypothesized that polymorphisms in PXR may contribute to CYP3A4 variability. The presence of PXR variants was investigated in two ethnic groups, Caucasians and Africans. Six missense mutations leading to variant PXR proteins were identified, and their consequences on CYP3A4 expression were analyzed. Expressed in LS174T cells, three protein variants, V140M, D163G, and A370T, exhibited altered basal and/or induced transactivation of CYP3A promoter reporter genes. Thus, these natural PXR protein variants may play a role in the observed interindividual variability of CYP3A4 expression and may be involved in rare, atypical responses to drugs or altered sensitivities to carcinogens.