The role of oxidative stress in the pathogenesis of infections with coronaviruses

Coronaviruses can cause serious respiratory tract infections and may also impact other end organs such as the central nervous system, the lung and the heart. The coronavirus disease 2019 (COVID-19) has had a devastating impact on humanity. Understanding the mechanisms that contribute to the pathogenesis of coronavirus infections, will set the foundation for development of new treatments to attenuate the impact of infections with coronaviruses on host cells and tissues. During infection of host cells, coronaviruses trigger an imbalance between increased production of reactive oxygen species (ROS) and reduced antioxidant host responses that leads to increased redox stress. Subsequently, increased redox stress contributes to reduced antiviral host responses and increased virus-induced inflammation and apoptosis that ultimately drive cell and tissue damage and end organ disease. However, there is limited understanding how different coronaviruses including SARS-CoV-2, manipulate cellular machinery that drives redox responses. This review aims to elucidate the redox mechanisms involved in the replication of coronaviruses and associated inflammation, apoptotic pathways, autoimmunity, vascular dysfunction and tissue damage that collectively contribute to multiorgan damage.

Positive temporal sharp waves in neonatal EEG

The clinical correlates and EEG characteristics of rolandic positive sharp waves in neonatal EEG have been studied systematically. Morphologically similar positive sharp waves have been reported to occur in the temporal areas (PTS). Their significance is, however, unclear. We reviewed fifty-two EEGs on patients from the Neonatal Intensive Care Unit of the University of Arkansas for Medical Sciences. Twenty-one of the EEGs which were reviewed had PTS. We correlated the PTS with the results of ultrasound of the head and with clinical evaluations. PTS are more strongly correlated with the occurrence of non-hemorrhagic than of hemorrhagic intracranial pathology.

Lingual thyroid: unusual appearance on computed tomography

A patient with a lingual thyroid was found to have inhomogeneous contrast enhancement on CT, findings not previously reported. Operative and histologic examination revealed marked thyroiditis and goitrous changes, explaining the CT findings.

Diagnosis of a viable abdominal pregnancy by magnetic resonance imaging

Abdominal pregnancy is an uncommon occurrence, and diagnosis by conventional means is often difficult. A case is presented in which a 29-week viable abdominal pregnancy was diagnosed by magnetic resonance imaging.

Magnetic resonance imaging: a noninvasive tool for fetal and placental physiology

Nuclear magnetic resonance imaging (MRI), a technique that utilizes biochemical information reflected in nuclear magnetic moments, can be used to image the uterus, fetus, and placenta of the human and nonhuman primate. MRI studies during pregnancy in the human and nonhuman primate provide soft-tissue structural information of considerable detail. MRI also offers the opportunity for noninvasive pharmacokinetic and toxicokinetic studies during pregnancy. Paramagnetic ions (Cu, Ni, Gd, Fe, Mn) after spin-lattice (T1) and spin-spin (T2) relaxation times in reproductive tissues. Changes in T1 and T2 alter the MRI image, reflecting uptake of paramagnetic ions by the uterus, placenta, or fetus. MRI provides a noninvasive method of monitoring body burden of selected xenobiotics during gestation. The use of paramagnetic labels on endogenous substances may also allow noninvasive determination of physiological parameters such as intervillous blood flow, placental metabolism, and placental transport during gestation.

Precise intraoperative location of gastrointestinal bleeding with a hand-held counter. Work in progress

The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.

Radionuclide-guided balloon occlusion pulmonary cineangiography: an adjunct to pulmonary arteriography

Fifty-eight patients, 38 of whom had pulmonary emboli, were evaluated for pulmonary occlusive disease with flow-directed balloon occlusion pulmonary cineangiography. Areas studied were selected by radionuclide perfusion lung scans and indeterminant areas of pulmonary occlusion were imaged on standard catheter pulmonary magnification cut films. In 4 of 38 patients, the balloon occlusion technique demonstrated peripheral pulmonary emboli not seen on standard pulmonary arteriography. Selective flow-directed balloon occlusion pulmonary cineangiography is an effective adjunct for evaluating some patients with pulmonary emboli.