Detection of CpG Methylation in G-Quadruplex Forming Sequences Using G-Quadruplex Ligands

Genomic DNA methylation is involved in many diseases and is expected to be a specific biomarker for even the pre-symptomatic diagnosis of many diseases. Thus, a rapid and inexpensive detection method is required for disease diagnosis. We have previously reported that cytosine methylation in G-quadruplex (G4)-forming oligonucleotides develops different G4 topologies. In this study, we developed a method for detecting CpG methylation in G4-forming oligonucleotides based on the structural differences between methylated and unmethylated G4 DNAs. The differences in G4 topologies due to CpG methylation can be discriminated by G4 ligands. We performed a binding assay between methylated or unmethylated G4 DNAs and G4 ligands. The binding abilities of fluorescent G4 ligands to BCL-2, HRAS1, HRAS2, VEGF G4-forming sequences were examined by fluorescence-based microtiter plate assay. The differences in fluorescence intensities between methylated and unmethylated G4 DNAs were statistically significant. In addition to fluorescence detection, the binding of G4 ligand to DNA was detected by chemiluminescence. A significant difference was also detected in chemiluminescence intensity between methylated and unmethylated DNA. This is the first study on the detection of CpG methylation in G4 structures, focusing on structural changes using G4 ligands.

Efficacy of “stay-at-home” policy and transmission of COVID-19 in Toronto, Canada: a mathematical modeling study

SummaryBackgroundIn many parts of the world, restrictive non-pharmaceutical interventions (NPI) that aim to reduce contact rates, including stay-at-home orders, limitations on gatherings, and closure of public places, are being lifted, with the possibility that the epidemic resurges if alternative measures are not strong enough. Here we aim to capture the combination of use of NPI’s and reopening measures which will prevent an infection rebound.MethodsWe employ an SEAIR model with household structure able to capture the stay-at-home policy (SAHP). To reflect the changes in the SAHP over the course of the epidemic, we vary the SAHP compliance rate, assuming that the time to compliance of all the people requested to stay-at-home follows a Gamma distribution. Using confirmed case data for the City of Toronto, we evaluate basic and instantaneous reproduction numbers and simulate how the average household size, the stay-at-home rate, the efficiency and duration of SAHP implementation, affect the outbreak trajectory.FindingsThe estimated basic reproduction number R_0 was 2.36 (95% CI: 2.28, 2.45) in Toronto. After the implementation of the SAHP, the contact rate outside the household fell by 39%. When people properly respect the SAHP, the outbreak can be quickly controlled, but extending its duration beyond two months (65 days) had little effect. Our findings also suggest that to avoid a large rebound of the epidemic, the average number of contacts per person per day should be kept below nine. This study suggests that fully reopening schools, offices, and other activities, is possible if the use of other NPIs is strictly adhered to.InterpretationOur model confirmed that the SAHP implemented in Toronto had a great impact in controlling the spread of COVID-19. Given the lifting of restrictive NPIs, we estimated the thresholds values of maximum number of contacts, probability of transmission and testing needed to ensure that the reopening will be safe, i.e. maintaining an Rt < 1.Research in contextEvidence before this studyA survey on published articles was made through PubMed and Google Scholar searches. The search was conducted from March 1 to August 13, 2020 and all papers published until the end of this research were considered. The following terms were used to screen articles on mathematical models: “household structure”, “epidemic model”, “SARS-CoV-2”, “COVID-19”, “household SIR epidemic”, “household SIS epidemic”, “household SEIR epidemic”, “quarantine, isolation model”, “quarantine model dynamics”, “structured model isolation”. Any article showing, in the title, application of epidemic models in a specific country/region or infectious diseases rather than SARS-CoV-2 were excluded. Articles in English were considered.Added value of this studyWe develop an epidemic model with household structure to study the effects of SAHP on the infection within households and transmission of COVID-19 in Toronto. The complex model provides interesting insights into the effectiveness of SAHP, if the average number of individuals in a household changes. We found that the SAHP might not be adequate if the size of households is relatively large. We also introduce a new quantity called symptomatic diagnosis’ completion ratio (d_c). This indicator is defined as the ratio of cumulative reported cases and the cumulative cases by episode date at time t, and it is used in the model to inform the implementation of SAHP.If cases are diagnosed at the time of symptom onset, isolation will be enforced immediately. A delay in detecting cases will lead to a delay in isolation, with subsequent increase in the transmission of the infection. Comparing different scenarios (before and after reopening phases), we were able to identify thresholds of these factors which mainly affect the spread of the infection: the number of daily tests, average number of contacts per individual, and probability of transmission of the virus. Our results show that if any of the three above mentioned factors is reduced, then the other two need to be adjusted to keep a reproduction number below 1. Lifting restrictive closures will require the average number of contacts a person has each day to be less than pre-COVID-19, and a high rate of case detection and tracing of contacts. The thresholds found will inform public health decisions on reopening.Implications of all the available evidenceOur findings provide important information for policymakers when planning the full reopening phase. Our results confirm that prompt implementation of SAHP was crucial in reducing the spread of COVID-19. Also, based on our analyses, we propose public health alternatives to consider in view of a full reopening. For example, for different post-reopening scenarios, the average number of contacts per person needs to be reduced if the symptomatic diagnosis’ completion ratio is low and the probability of transmission increases. Namely, if fewer tests are completed and the usage of NPI’s decreases, then the epidemic can be controlled only if individuals can maintain contact with a maximum average number of 4-5 people per person per day. Different recommendations can be provided by relaxing/strengthening one of the above-mentioned factors.

Alzheimer’s Disease: Causes, Mechanisms, and Steps Toward Prevention

Alzheimer’s disease (AD) is the most common form of dementia in the elderly; it is clinically characterized by progressive memory loss and catastrophic cognitive dysfunction. Neuropathologically, the brains of AD patients are characterized by abundant beta-amyloid plaques, neurofibrillary tangles, and neuroinflammation. To date, this fatal disease ranks as the sixth leading cause of death; 5.8 million people in the United States are estimated to have the disease, and the total incidence of AD-related dementia is projected to grow to 16 million by 2050. Currently, there is no cure or any reliable means for pre-symptomatic diagnosis of AD. AD is a genetically heterogenous and multifactorial disease, and a variety of molecular mechanisms have been suggested to underlie its etiology and pathogenesis. A better understanding of pathogenic mechanisms underlying the development of AD pathology and symptoms would accelerate the development of effective therapeutic strategies for preventing and treating AD. Here, we present a comprehensive overview of the pathogenetic and molecular mechanisms underlying AD along with current therapeutic and lifestyles interventions being investigated for the prevention and treatment of this devastating neurological disorder.

Community based cross sectional study: to assess the prevalence of arthritic symptoms in an army garrison in large city of North India

Background: Arthritis affects almost 350 million people globally and is one of the leading causes of disability in the world. The prevalence in India is like that in developed countries. Symptoms of arthritis have been found to be influenced by alcohol intake, smoking, obesity and type of diet which lead to aggravation in pain, exacerbation in disease activity and deterioration in general health.Methods: Present community-based cross-sectional study was conducted in a large military station in North India over a period of one month. Armed Forces personnel and their family members aged 18 yrs and above residing in military station and consenting to the study were included. A sample of 1475 was studied.Results: The age of participants ranged from 18 to 70 yrs (median 32±7.4 yrs) with 20.54% females and 79.46% males. The prevalence of symptoms suggestive of Gout, RA, OA and Spondyloarthritis was 8.95% (95% CI, 7.54, 10.52), 3.25% (2.41, 4.29), 11.32% (9.75, 13.05) and 14.17% (12.43, 16.05), respectively. Symptoms suggestive of RA were found to be significantly associated with female gender, those of Gout and Spondyloarthritis with male gender, while OA did not have any gender predisposition.Conclusions: The population with symptoms of arthritis needs to be identified early by early symptomatic diagnosis and measures instituted for appropriate management to prevent future complications and associated morbidity.

Validity of discharge ICD-10 codes in detecting the etiologies of endogenous Cushing’s syndrome

Objective To investigate the validity of discharge ICD-10 codes in detecting the etiology of endogenous Cushing’s syndrome (CS) in hospitalized patients. Methods We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CS etiology-related ICD-10 codes or code combinations by comparing hospital discharge administrative data (DAD) with established diagnoses from medical records. Results Coding for patients with adrenocortical adenoma (ACA) and those with bilateral macronodular adrenal hyperplasia (BMAH) demonstrated disappointingly low sensitivity at 78.8% (95% CI: 70.1–85.6%) and 83.9% (95% CI: 65.5–93.9%), respectively. BMAH had the lowest PPV of 74.3% (95% CI: 56.4–86.9%). In confirmed ACA patients, the sensitivity for ACA code combinations was higher in patients initially admitted to the Department of Endocrinology before surgery than that in patients directly admitted to the Department of Urology (90.0 vs 73.1%, P = 0.033). The same phenomenon was observed in the PPV for the BMAH code (100.0 vs 60.9%, P = 0.012). Misinterpreted or confusing situations caused by coders (68.1%) and by the omission or denormalized documentation of symptomatic diagnosis by clinicians (26.1%) accounted for the main source of coding errors. Conclusions Hospital DAD is an effective data source for evaluating the etiology of CS but not ACA and BMAH. Improving surgeons’ documentation, especially in the delineation of symptomatic and locative diagnoses in discharge abstracts; department- or disease-specific training for coders and more multidisciplinary collaboration are ways to enhance the applicability of administrative data for CS etiologies.

Monogenic and oligogenic cardiovascular diseases: genetics of arrhythmias—catecholaminergic polymorphic ventricular tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited disorder associated with syncope and sudden death manifesting in the young during sympathetic activation. The electrocardiogram is normal and the heart is structurally normal. The diagnosis is usually made with an exercise stress test that shows a typical pattern of onset and offset of adrenergically induced ventricular arrhythmias. Molecular screening of RyR2, the major CPVT gene, is recommended whenever the suspicion of CPVT is high. If a disease-causing mutation is identified, cascade screening allows pre-symptomatic diagnosis among family members. All affected subjects should be treated with beta blockers (nadolol or propranolol). Preliminary data support the association of beta blockers with flecainide. After a cardiac arrest, an implantable cardioverter defibrillator (ICD) should be implanted, but it is accompanied by a disquietingly high incidence of adverse effects. After syncope on beta blocker therapy, left cardiac sympathetic denervation is most effective, preserves quality of life, and does not preclude a subsequent ICD implantation.