One‐step and sequential SARSCOV‐2 polymerase chain reaction tests would not work every time

IntroductionRT‐PCR is widely used as a diagnostic test for the detection of SARS‐CoV‐2. In this study, we aim to describe the clinical utility of serial PCR testing in the final detection of COVID‐19.MethodWe collected multiple nasopharyngeal swab samples from patients who had negative RT‐PCR test on the first day after hospitalization. RT‐PCR tests were performed on the second day for all patients with initial negative result. For the patients with secondary negative results on day 2, tertiary RT‐PCR tests were performed on day 3 after hospitalization.ResultAmong 68 patients with initial negative test results, at the end of follow‐up, the mortality number was 20 (29.4%). About 33.8% of patients had subsequent positive PCR test results for the second time and 17.4% of the patients who performed third PCR test had positive result.ConclusionBased on this study, serial RT‐PCR testing is unlikely to yield additional information.     

Analyzing Survival Rate of Leukemia Patients Applying Long Term Exponential Model

Background: Making progressin treatment of all branches of cancers has increasedthe percent of patients that never experience the event of interest. These cases are called immune or cure and models for handling the data included cure fraction rate, are referred to as cure model or long-term survival models. Methods:The data for this historical cohort study, were collected from leukemia patients diagnosed between 2007 to 2014 and followed up until 2016 in Taleghani hospital and received BMT (Bone Marrow Transplant). Some data had to be excluded because of incomplete information. Using recorded files mostly and phone calls rarely, were made to confirm whether the patients were still alive or not. Death due to leukemia was regarded as interested event. Analysis were performed by R version 3.4.1and Stata version 14. Results: Number of recurrents after receiving BMT, pre-transplant Hb and age at diagnosis were found as significant prognostics of survival time. HD patients had the highest 5-years overall survival in category of diagnosis type with 81.3%. Cure fraction was estimated to be 64.1%. Conclusion: According to high percentage of censoring, using long-term model had better fit.     

Comparison of PASL,PCASL, and background‐suppressed 3D PCASL in mild cognitive impairment

We compared three implementations of single‐shot arterial spin labeled (ASL) perfusion magnetic resonance imaging: two‐dimensional (2D) pulsed ASL (PASL), 2D pseudocontinuous ASL (PCASL), and background‐suppressed (BS) 3D PCASL obtained in a cohort of patients with mild cognitive impairment (MCI) and elderly controls. Study subjects also underwent ¹⁸F‐fluorodeoxyglucose positron emission tomography (¹⁸F‐FDG PET). While BS 3D PCASL showed the lowest (P < 0.001) gray matter–white matter cerebral blood flow (CBF) contrast ratio, it provided the highest (P < 0.001) temporal signal‐to‐noise ratio. Mean relative CBF estimated using the PCASL methods in posterior cingulate cortex (PCC), precuneus, and hippocampus showed hypoperfusion in the MCI cohort compared to the controls consistent with hypometabolism measured by ¹⁸F‐FDG PET. BS 3D PCASL demonstrated the highest discrimination between controls and patients with effect size comparable to that seen with ¹⁸F‐FDG PET. 2D PASL did not demonstrate group differentiation with relative CBF in any ROI, whereas 2D PCASL demonstrated significant differences only in PCC and hippocampus. Mean global CBF values did not differ across methods and were highly correlated; however, the correlations were significantly higher (P < 0.001) when either the same labeling (PCASL) or the same acquisition strategy (2D) was used as compared to when both the labeling and readout methods differed. In addition, there were differences in regional distribution of CBF between the three modalities, which can be attributed to differences in sequence parameters. These results demonstrate the superiority of ASL with PCASL and BS 3D readout as a biomarker for regional brain function changes in MCI. Hum Brain Mapp 38:5260–5273, 2017. © 2017 Wiley Periodicals, Inc.     

Distribution of endogenous apoprotein B-containing lipoproteins in normal and injured aortas of normocholesterolemic rabbits.

The distribution of endogenous apolipoprotein B (apo B) was studied in both normal and balloon catheter-injured aortas of standard fed rabbits. Using light and electron microscopy, the distribution within entire aortic walls and individual tissue compartments was investigated by immunocytochemistry using an antibody raised against rabbit apo B. The concentration of apo B across the vessel wall dropped sharply from the luminal front towards the media of the normal aortas. The strong superficial reaction was mainly due to a heavy, yet specific, labelling of endothelial cells. Significant concentrations of apo B were also detected within the innermost regions of the extracellular space. The characteristics associated with the labelling of the intimal layer suggested an intense uptake and transcellular transport of apo B by endothelial cells. In contradistinction, normal smooth muscle cells did not appear to be labelled. In the previously injured aortas, the same features of strong superficial apo B labelling were present in the areas covered by regenerated endothelial cells, but not in those persistently deendothelialized. The smooth muscle cells of these regions appeared to show a low uptake of apo B. The increased concentrations of apo B in deeper interstitial areas of injured aortas, indicated the contribution of the extracellular matrix to apo B accumulation. This was especially prominent in the advanced lesions, selectively developed within neointima covered by regenerated endothelium. A rather uniform labelling pattern accompanying small lipid particle deposits, suggested a direct extracellular accumulation of circulating lipoproteins. Intensely labelled foam cells and irregularly distributed apo B within areas of cellular necrosis were detected as well. Injury-mediated responses of the cellular and extracellular aortic components can trigger the development of lipoprotein accumulations characteristic of atherosclerosis within aortas of normocholesterolemic animals.     

A 2017 update: Challenging the cosmetic procedural delay following oral isotretinoin therapy

For decades it has been widely accepted that elective procedures should be delayed for at least 6-months following completion of isotretinoin therapy. However, numerous 2017 publications demonstrate the need for change in best practice. The evidence has yet to be succinctly summarized in a single article or in a stand-alone quick reference algorithm for physicians. This article’s review of all 2017 publications confirms that the 6-month delay is not necessary for all procedures and provides a simple algorithmic approach to summarize the updated recommendations for procedural delay of cosmetic procedures following systemic isotretinoin therapy. This is a useful tool for clinicians and allows patients to receive the most appropriate and timely cosmetic therapy to minimize the psychosocial impact of the skin condition.     

A systematic review of the relationship between glycemic control and necrobiosis lipoidica diabeticorum in patients with diabetes mellitus

The association of specific skin disorders with diabetes mellitus (DM) has been well established. Current literature suggests that approximately 30–91% of patients with diabetes will experience at least one cutaneous manifestation of this systemic disease in their lifetime. To date, there are limited articles summarizing the link between necrobiosis lipoidica diabeticorum (NLD) prognosis and glycemic control in patients with diabetes. The objective of the study is to summarize and appraise the available evidence assessing the relationship between glycemic control and NLD. A literature search was conducted based on MEDLINE (1946–2015), EMBASE (1980–2015), Google Scholar, and PubMed for publications that described the results of diabetes control and NLD. Further studies were identified from bibliographies of all relevant studies, gray literature, and annual scientific assemblies. All studies investigating the relationship between DM (type 1 and type 2) management and NLD were included. Two reviewers independently extracted data including demographics, type of diabetes management measures (glucose, HbA1c, insulin), comorbidities, and outcome. A total of 622 studies were identified, and 10 studies met the inclusion and exclusion criteria: two case series and eight case reports. Of the 24 patients with NLD, 13 patients reported resolution of NLD after implementing various methods of glycemic control (diabetic diet consisting of 1600 kcal/day [1 patient], insulin regimen [3 patients], and pancreatic transplantation [9 patients]). Glycemic control may have a role in influencing the prognosis of necrobiosis lipoidica in patients with diabetes; however, there is currently insufficient evidence to support or refute this claim.     

PET imaging for differentiating recurrent brain tumor from radiation necrosis

The exact incidence of true radiation necrosis is largely unknown. It is probably much less frequent than indicated by MR or CT findings. Differentiating radiation necrosis from recurrent tumor is a diagnostic challenge, however, and has important implications for the patient's management. Even though the first results were published 20 years ago, the total number of case studies using FDG-PET in this indication remains limited. Several reports are also hampered by methodologic limitations. The technique has been largely criticized, notably in articles that themselves were not completely free of methodological flaws. Overall however, FDG-PET seems to be a valuable clinical tool. As a general rule, suspicious lesions on MR imaging that show increased FDG uptake (ie, uptake equal to or great than that in normal cortex) are likely to represent tumor recurrence. Sensitivity is an issue, especially but not exclusively with low-grade gliomas. Although false-positive results may occur, specificity is usually high in routine clinical practice. Coregistration with MR imaging surely improves the diagnostic performances of FDG-PET because it helps delineate the suspicious area. Another important aspect is the prognostic value of FDG uptake, which is now well established. It seems clear that only the combination of FDG with a radiolabeled amino acid analogue (MET or a more recent fluorinated compound) can provide a comprehensive characterization of suspected brain tumor recurrence.