Identification of a novel inhibitor of SARS-CoV-2 main protease: an in silico, biochemical, and cell-based approach.

The recurrent nature of coronavirus outbreaks, severity of the COVID-19 pandemic, rapid emergence of novel variants, and concerns over the effectiveness of existing vaccines against novel variants have highlighted the need to develop therapeutic interventions. Targeted efforts to identify inhibitors of crucial viral proteins are the preferred strategy. In this study, we screened FDA-approved and natural product libraries using in silico approach for potential hits against the SARS-CoV-2 main protease (Mpro) and experimentally validated their potency using in vitro biochemical and cell-based assays. Seven potential hits were identified through in silico screening and were subsequently evaluated in SARS-CoV-2-based cell-free assays, followed by testing in the HCoV-229E-based culture system. Of the tested compounds, 4-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1-isopropyl-1H-benzofuro[3,2-b]pyrazolo[4,3-e]pyridin-3(2H)-one (PubChem CID:71755304, hereafter referred to as STL522228) exhibited significant antiviral activity. Subsequently, its potential as a novel COVID therapeutic molecule was validated in the SARS-CoV-2-culture system, where STL522228 demonstrated superior antiviral activity (EC50 = 0.44 µm) compared to Remdesivir (EC50 = 0.62 µm). Based on these findings, we report the strong anti-coronavirus activity of STL522228, and propose that it as a promising pan-coronavirus Mpro inhibitor for further experimental and preclinical validation.

Ready to scan? A systematic review of point of care ultrasound (PoCUS) for screening of obstructive sleep apnea (OSA) in the pediatric population.

STUDY OBJECTIVE: Diagnosis of obstructive sleep apnea (OSA) in pediatric practice is challenging, as screening questionnaires are inadequate and sleep studies are resource limited and time-consuming. A recent systematic review and meta-analysis of perioperative point-of-care ultrasound (PoCUS) in adults identified several parameters which correlate with OSA diagnosis and are the subject of an ongoing prospective study. The objective of this systematic review was to evaluate the usefulness of surface airway ultrasound as a PoCUS tool for OSA screening in the pediatric population. DESIGN: Databases were searched for observational cohort studies and randomized controlled trials of patients under 18 years of age undergoing quantitative surface US measurement of extra-thoracic airway structures where correlation or association was examined either directly to OSA diagnosis or indirectly to an alternative reference measure. Diagnostic properties and correlation between US parameters (index test) and reference measures were evaluated where possible. MAIN RESULTS: Of the initial 8499 screened articles, 12 articles (8 airway, 4 non-airway) evaluating 1237 patients were included. Six of these studies were conducted in the sleep/obesity clinic and six in in the perioperative population. Ten studies were prospective and two were cross sectional studies. Airway parameters which correlated with moderate-severe OSA were lateral pharyngeal wall thickness and total neck thickness at the retropharyngeal level. Tonsil volume was not correlated with OSA diagnosis or severity. In tonsillectomy patients, tonsil volume on preoperative ultrasound correlated well with volume of surgical specimens. Adenoid thickness correlated strongly with radiological and endoscopic measures of size and occlusion. CONCLUSION: Ultrasound measurement in children indicates several parameters which correlate with OSA diagnosis or with other reference measurements. This has not yet been validated as a diagnostic tool, however the recent emergence of research in this area is encouraging and the findings from this review will inform future studies.

Nipple Adenoma: Case Report of a Rare Entity.

A nipple adenoma is a rare benign breast tumor. The commonest presentation of this rare entity is nipple erosion, serosanguinous discharge, induration, or tumor formation at the nipple. It often mimics malignant breast lesions or nipple eczema and is mistaken for Paget's disease of the nipple or dermatological pathology. It may be misdiagnosed pathologically as ductal carcinoma of the breast. This may cause a diagnostic delay or a faulty diagnosis. Treatment is the excision of the tumor with or without nipple excision. Here, we report a case of nipple adenoma that projected out of the nipple along with nipple erosion, serosanguinous discharge, and occasional bleeding from the adenoma. A 37- year-old woman presented with a tumor on her right nipple for eight months, with the erosion of the nipple and serosanguinous discharge. The patient gave a history of a small amount of bleeding occasionally. Axilla was normal. The patient was advised to have a mammosonography. It showed an oval-shaped, well-demarcated, hypoechoic, uniformly solid nodule in the right nipple. There was no microcalcification seen on mammography. A punch biopsy was done to establish the diagnosis. It showed ductal hyperplasia and papillary proliferation of glandular structures suggestive of nipple adenoma. Complete resection of the tumor with partial excision of the nipple was done with a satisfactory cosmetic result. Though very uncommon, the possibility of nipple adenoma should be thought of when a patient presents with nipple erosion and discharge with or without a clinically obvious tumor. Timely diagnosis with histopathological correlation is important since it allows for less invasive surgical methods. In our case, we could attain a cosmetically satisfactory outcome without a remnant tumor. Paget's disease of the nipple also has a similar clinical presentation, and it is a premalignant condition. The objective of presenting this case is to highlight the possibility of this rare benign condition, which may be easily missed clinically and also demands careful histopathological examination for its correct diagnosis.

Biochemical and Biophysical Characterisation of the Hepatitis E Virus Guanine-7-Methyltransferase.

Hepatitis E virus (HEV) is an understudied pathogen that causes infection through fecal contaminated drinking water and is prominently found in South Asian countries. The virus affects ~20 million people annually, leading to ~60,000 infections per year. The positive-stranded RNA genome of the HEV genotype 1 has four conserved open reading frames (ORFs), of which ORF1 encodes a polyprotein of 180 kDa in size, which is processed into four non-structural enzymes: methyltransferase (MTase), papain-like cysteine protease, RNA-dependent RNA polymerase, and RNA helicase. MTase is known to methylate guanosine triphosphate at the 5'-end of viral RNA, thereby preventing its degradation by host nucleases. In the present study, we cloned, expressed, and purified MTase spanning 33-353 amino acids of HEV genotype 1. The activity of the purified enzyme and the conformational changes were established through biochemical and biophysical studies. The binding affinity of MTase with magnesium ions (Mg2+) was studied by isothermal calorimetry (ITC), microscale thermophoresis (MST), far-UV CD analysis and, fluorescence quenching. In summary, a short stretch of nucleotides has been cloned, coding for the HEV MTase of 37 kDa, which binds Mg2+ and modulate its activity. The chelation of magnesium reversed the changes, confirming its role in enzyme activity.

Evaluating the impact of gabapentinoids on sleep health in patients with chronic neuropathic pain: a systematic review and meta-analysis.

Chronic neuropathic pain (NP) is debilitating and impacts sleep health and quality of life. Treatment with gabapentinoids (GBs) has been shown to reduce pain, but its effects on sleep health have not been systematically evaluated. The objective of this systematic review and meta-analysis was to assess the relationship between GB therapy dose and duration on sleep quality, daytime somnolence, and intensity of pain in patients with NP. Subgroup comparisons were planned for high- vs low-dose GBs, where 300 mg per day or more of pregabalin was used to classify high-dose therapy. Trial data were segregated by duration less than 6 weeks and 6 weeks or greater. Twenty randomized controlled trials were included. Primary outcome measures included pain-related sleep interference and incidence of daytime somnolence. Secondary outcomes included daily pain scores (numerical rating scale 0-10) and patient global impression of change. Significant improvement in sleep quality was observed after 6 weeks of GB treatment when compared with placebo (standardized mean difference 0.39, 95% confidence interval 0.32-0.46 P < 0.001). Increased daytime somnolence was observed among all GB-treated groups when compared with placebo. Treated patients were also more likely to report improvement of patient global impression of change scores. Pain scores decreased significantly in patients both after 6 weeks of treatment (P < 0.001) and in trials less than 6 weeks (P = 0.017) when compared with placebo. Our data demonstrate that GBs have a positive impact on sleep health, quality of life, and pain in patients with NP syndromes. However, these benefits come at the expense of daytime somnolence.

Point-of-Care Ultrasound for Obstructive Sleep Apnea Screening: Are We There Yet? A Systematic Review and Meta-analysis.

BACKGROUND: Perioperative diagnosis of obstructive sleep apnea (OSA) has important resource implications as screening questionnaires are overly sensitive, and sleep studies are expensive and time-consuming. Ultrasound (US) is a portable, noninvasive tool potentially useful for airway evaluation and OSA screening in the perioperative period. The objective of this systematic review was to evaluate the correlation of surface US with OSA diagnosis and to determine whether a point-of-care ultrasound (PoCUS) for OSA screening may help with improved screening in perioperative period. METHODS: A search of all electronic databases including Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from database inception to September 2017. Inclusion criteria were observational cohort studies and randomized controlled trials of known or suspected OSA patients undergoing surface US assessment. Article screening, data extraction, and summarization were conducted by 2 independent reviewers with ability to resolve conflict with supervising authors. Diagnostic properties and association between US parameters (index test) and OSA diagnosis using sleep study (reference standard) were evaluated. The US parameters were divided into airway and nonairway parameters. A random-effects meta-analysis was planned, wherever applicable. RESULTS: Of the initial 3865 screened articles, 21 studies (7 airway and 14 nonairway) evaluating 3339 patients were included. Majority of studies were conducted in the general population (49%), respirology (23%), and sleep clinics (12%). No study evaluated the use of US for OSA in perioperative setting. Majority of included studies had low risk of bias for reference standard and flow and timing. Airway US parameters having moderate-good correlation with moderate-severe OSA were distance between lingual arteries (DLAs > 30 mm; sensitivity, 0.67; specificity, 0.59; 1 study/66 patients); mean resting tongue thickness (>60 mm; sensitivity, 0.85; specificity, 0.59; 1 study/66 patients); tongue base thickness during Muller maneuver (MM; sensitivity, 0.59; specificity, 0.78; 1 study/66 patients); and a combination of neck circumference and retropalatal (RP) diameter shortening during MM (sensitivity, 1.0; specificity, 0.65; 1 study/104 patients). Nonairway US parameters having a low-moderate correlation with moderate-severe OSA were carotid intimal thickness (pooled correlation coefficient, 0.444; 95% confidence interval [CI], 0.320-0.553; P value = .000, 8 studies/727 patients) and plaque presence (sensitivity, 0.24-0.75; specificity, 0.13-1.0; 4 studies/1183 patients). CONCLUSIONS: We found that a number of airway and nonairway parameters were identified with moderate to good correlation with OSA diagnosis in the general population. In future studies, it remains to be seen whether PoCUS screening for a combination of these parameters can address the pitfalls of OSA screening questionnaires.