Imaging in the aftermath of COVID-19: what to expect.

No abstract availabl

Synthesis of 3',5'-Cyclic Phosphate and Thiophosphate Esters of 2'-C-Methyl Ribonucleosides

2'-C-Methylnucleosides are known to exhibit antiviral activity against Hepatitis C virus. Since the inhibitory activity depends on their intracellular conversion to 5'-triphosphates, dosing as appropriately protected 5'-phosphates or 5'-phosphorothioates appears attractive. For this purpose, four potential pro-drugs of 2'-C-methylguanosine, i.e., 3',5'-cyclic phosphorothioate of 2'-C-methylguanosine and 2'-C,O6-dimethylguanosine, 1 and 2, respectively, the S-[(pivaloyloxy)methyl] ester of 2'-C,O6-dimethylguanosine 3',5'-cyclic phosphorothioate and the O-methyl ester of 2'-C,O6-dimethylguanosine 3',5'-cyclic phosphate, 3 and 4, respectively, have been prepared

5 ',5 '-Phosphodiesters and esterase labile triesters of 2 '-C-methylribonucleosides

Bis(2'-C-methyladenosin-5'-yl) (11), bis(2'-C-methylguanosin-5'-yl) (13), bis(2'-C-methyluridin-5'-yl) (15) and 2'-C-methylguanosin-5'-yl 2'-C-methyluridin-5'-yl (16) phosphodiesters have been prepared as pro-drug candidates for the respective 2'-C-methylribonucleoside 5'-monophosphates, expectedly exhibiting antiviral activity against Hepatitis C virus. Additionally, the bis(2'-C-methyladenosine) diester has been converted to 3-acetyloxymethoxy-2,2-bis(ethoxycarbonyl)propyl (19) or pivaloyloxymethyl (20) triester. The underlying idea is that the 5',5'-phosphodiester is first released by intracellular carboxyesterases and subsequently cleaved to nucleoside and nucleoside 5'-monophosphate by phosphodiesterases

Imaging features and differential diagnoses of non-neoplastic diffuse mediastinal diseases.

Acute or chronic non-neoplastic diffuse mediastinal diseases have multiple causes, degrees of severity, and a wide range of management. Some situations require emergency care while others do not need specific treatment. Although the diagnosis may be suspected on chest X-ray, it is mainly based on CT. A delayed recognition is not uncommonly observed. Some findings may prompt the radiologist to look for specific associated injuries or lesions.This pictorial review will successively describe the various non-neoplastic causes of diffuse mediastinal diseases with their typical findings and major differentials.First, pneumomediastinum that can be provoked by extra- or intra-thoracic triggers requires the knowledge of patient's history or recent occurrences. Absence of any usual etiological factor should raise suspicion of cocaine inhalation in young individuals.Next, acute mediastinitis may be related to post-operative complications, esophageal perforation, or contiguous spread of odontogenic or retropharyngeal infections. The former diagnosis is not an easy task in the early stage, owing to the similarities of imaging findings with those of normal post-operative appearance during the first 2-3 weeks.Finally, fibrosing mediastinitis that is linked to an excessive fibrotic reaction in the mediastinum with variable compromise of mediastinal structures, in particular vascular and airway ones. Differential diagnosis includes tumoral and inflammatory infiltrations of the mediastinum

Non-circumferential membranous resection of the trachea for paraganglioma: A case report.

Paraganglioma is a rare neuroendocrine tumor and may sometimes be located in the membranous part of the trachea. We report the case of a 52-year-old man presenting a paraganglioma just above the carina with obstructive symptoms. The patient successfully underwent a non-circumferential tracheal membranous resection, followed by latissimus dorsi muscle flap repair, under peripheral extra-corporeal membrane oxygenation (ECMO). Complex carinal resection can be avoided for tracheal membranous tumors and replaced with non-circumferential resection and direct reconstruction with a muscle flap. In addition, ECMO support may be used for airway resection and reconstruction. Tracheal membranous tumors can be managed without circumferential resection or direct anastomosis

Non-circumferential membranous resection of the trachea for paraganglioma: A case report.

Paraganglioma is a rare neuroendocrine tumor and may sometimes be located in the membranous part of the trachea. We report the case of a 52-year-old man presenting a paraganglioma just above the carina with obstructive symptoms. The patient successfully underwent a non-circumferential tracheal membranous resection, followed by latissimus dorsi muscle flap repair, under peripheral extra-corporeal membrane oxygenation (ECMO). Complex carinal resection can be avoided for tracheal membranous tumors and replaced with non-circumferential resection and direct reconstruction with a muscle flap. In addition, ECMO support may be used for airway resection and reconstruction. Tracheal membranous tumors can be managed without circumferential resection or direct anastomosis

Pseudoinfarction pattern in a patient with hyperkalemia, diabetic ketoacidosis and normal coronary vessels: a case report

<p>Abstract</p> <p>Introduction</p> <p>A rare electrocardiographic finding of hyperkalemia is ST segment elevation or the so called 'pseudoinfarction' pattern. It has been suggested that hyperkalemia causes the 'pseudoinfarction' pattern not only through its direct myocardial effects, but also through other mechanisms, such as anoxia, acidosis, and coronary artery spasm.</p> <p>Case presentation</p> <p>A 33-year-old Caucasian woman with insulin-treated diabetes presented with continuous epigastric pain of four hours duration. Her coronary heart disease risk factors apart from diabetes included hypercholesterolemia and smoking. Her initial electrocardiogram revealed ST segment elevation in the anteroseptal leads consistent with anterior myocardial infarction. Blood tests revealed hyperglycemia, hyperkalemia, metabolic acidosis and urine ketones, while a bed-side cardiac echocardiogram showed no segmental wall motion abnormality. We provisionally diagnosed diabetic ketoacidosis that was possibly precipitated by acute myocardial infarction, as there were findings in favor of (epigastric pain, electrocardiogram pattern, presence of 3 coronary heart disease risk factors) and against (young age, normal echocardiogram) the diagnosis of acute myocardial infarction. We performed cardiac angiography in order to exclude an anterior acute myocardial infarction, which could lead to myocardial damage and possible severe complications should there be a delay in treatment. Angiography revealed normal coronary arteries. During the procedure, ST segment elevation in the anteroseptal leads was still present in our patient's electrocardiogram results.</p> <p>Conclusion</p> <p>ST segment elevation is a rare manifestation of hyperkalemia. In our patient, coronary spasm did not contribute to such an electrocardiography finding.</p

Long-term voluntary wheel running does not alter vascular amyloid burden but reduces neuroinflammation in the Tg-SwDI mouse model of cerebral amyloid angiopathy

Background: Cardiovascular exercise (CVE) has been shown to be protective against cognitive decline in aging and the risk for dementias, including Alzheimer’s Disease (AD). CVE has also been shown to have several beneficial effects on brain pathology and behavioral impairments in mouse models of AD; however, no studies have specifically examined the effects of CVE on cerebral amyloid angiopathy (CAA), which is the accumulation of amyloid-beta (Aβ) in the cerebral vasculature. CAA may be uniquely susceptible to beneficial effects of CVE interventions due to the location and nature of the pathology. Alternatively, CVE may exacerbate CAA pathology, due to added stress on already compromised cerebral vasculature. Methods: In the current study, we examined the effects of CVE over many months in mice, thereby modeling a lifelong commitment to CVE in humans. We assessed this voluntary CVE in Tg-SwDI mice, a transgenic mouse model of CAA that exhibits behavioral deficits, fibrillar vascular Aβ pathology, and significant perivascular neuroinflammation. Various “doses” of exercise intervention (0 h (“Sedentary”), 1 h, 3 h, 12 h access to running wheel) were assessed from ~ 4 to 12 months of age for effects on physiology, behavior/cognitive performance, and pathology. Results: The 12 h group performed the greatest volume of exercise, whereas the 1 h and 3 h groups showed high levels of exercise intensity, as defined by more frequent and longer duration running bouts. Tg-SwDI mice exhibited significant cerebral vascular Aβ pathology and increased expression of pro-inflammatory cytokines as compared to WT controls. Tg-SwDI mice did not show motor dysfunction or altered levels of anxiety or sociability compared to WT controls, though Tg-SwDI animals did appear to exhibit a reduced tendency to explore novel environments. At all running levels, CAA pathology in Tg-SwDI mice was not significantly altered, but 12-h high-volume exercise showed increased insoluble Aβ burden. However, CVE attenuated the expression of pro-inflammatory cytokines TNF-α and IL-6 and was generally effective at enhancing motor function and reducing anxiety-like behavior in Tg-SwDI mice, though alterations in learning and memory tasks were varied. Conclusions: Taken together, these results suggest that CAA can still develop regardless of a lifespan of substantial CVE, although downstream effects on neuroinflammation may be reduced and functional outcomes improved

The Effects of Volume Versus Intensity of Long-Term Voluntary Exercise on Physiology and Behavior in C57/Bl6 Mice

Cardiovascular exercise (CVE) is associated with healthy aging and reduced risk of disease in humans, with similar benefits seen in animals. Most rodent studies, however, have used shorter intervention periods of a few weeks to a few months, begging questions as to the effects of longer-term, or even life-long, exercise. Additionally, most animal studies have utilized a single exercise treatment group – usually unlimited running wheel access – resulting in large volumes of exercise that are not clinically relevant. It is therefore incumbent to determine the physiological and cognitive/behavioral effects of a range of exercise intensities and volumes over a long-term period that model a lifelong commitment to CVE. In the current study, C57/Bl6 mice remained sedentary or were allowed either 1, 3, or 12 h of access to a running wheel per day, 5 days/weeks, beginning at 3.5–4 months of age. Following an eight-month intervention period, animals underwent a battery of behavioral testing, then euthanized and blood and tissue were collected. Longer access to a running wheel resulted in greater volume and higher running speed, but more breaks in running. All exercise groups showed similarly reduced body weight, increased muscle mass, improved motor function on the rotarod, and reduced anxiety in the open field. While all exercise groups showed increased food intake, this was greatest in the 12 h group but did not differ between 1 h and 3 h mice. While exercise dose-dependently increased working memory performance in the y-maze, the 1 h and 12 h groups showed the largest changes in the mass of many organs, as well as alterations in several behaviors including social interaction, novel object recognition, and Barnes maze performance. These findings suggest that long-term exercise has widespread effects on physiology, behavior, and cognition, which vary by “dose” and measure, and that even relatively small amounts of daily exercise can provide benefits