Intrinsic D614G and P681R/H mutations in SARS-CoV-2 VoCs Alpha, Delta, Omicron and viruses with D614G plus key signature mutations in spike protein alters fusogenicity and infectivity.

The SARS-CoV-2 virus has been rapidly evolving over the time and the genetic variation has led to the generation of Variants of Concerns (VoC), which have shown increased fitness. These VoC viruses contain the key mutations in the spike protein which have allowed better survival and evasion of host defense mechanisms. The D614G mutation in the spike domain is found in the majority of VoC; additionally, the P681R/H mutation at the S1/S2 furin cleavage site junction is also found to be highly conserved in major VoCs; Alpha, Delta, Omicron, and its' current variants. The impact of these genetic alterations of the SARS-CoV-2 VoCs on the host cell entry, transmissibility, and infectivity has not been clearly identified. In our study, Delta and D614G + P681R synthetic double mutant pseudoviruses showed a significant increase in the cell entry, cell-to-cell fusion and infectivity. In contrast, the Omicron and P681H synthetic single mutant pseudoviruses showed TMPRSS2 independent cell entry, less fusion and infectivity as compared to Delta and D614G + P681R double mutants. Addition of exogenous trypsin further enhanced fusion in Delta viruses as compared to Omicron. Furthermore, Delta viruses showed susceptibility to both E64d and Camostat mesylate inhibitors suggesting, that the Delta virus could exploit both endosomal and TMPRSS2 dependent entry pathways as compared to the Omicron virus. Taken together, these results indicate that the D614G and P681R/H mutations in the spike protein are pivotal which might be favoring the VoC replication in different host compartments, and thus allowing a balance of mutation vs selection for better long-term adaptation.

Active upper aerodigestive tract hemorrhage in patients with head and neck cancers: the "dot-in-sludge" sign.

Active extravasation into the upper aerodigestive tract is a dramatic and potentially life-threatening complication in patients with head and neck cancers. It prompts presentation to the emergency room and subsequent urgent imaging to identify the source of hemorrhage. Imaging of these patients may be complicated by treatment-altered anatomy, posing a challenge to the emergency radiologist who needs to rapidly identify the presence of active hemorrhage and the potential source vessel. This retrospective review summarizes the clinical and imaging findings of 6 oropharyngeal and oral cavity squamous cell cancer (SCC) patients with active upper aerodigestive tract hemorrhage. Most patients had advanced stage disease and prior radiation therapy. All CECT or CTA exams on presentation demonstrated the "dot-in-sludge" sign of active extravasation, as demonstrated by a "dot" of avidly enhancing extravasated contrast material layered against a background "sludge" of non-enhancing debris in the lumen of the upper aerodigestive tract. Common sources of hemorrhage included the lingual, facial, and superior thyroidal arteries. Familiarity with these findings will help radiologists increase their accuracy and confidence in interpreting these urgent, complex examinations.

Ecotoxicological assessment of tannery effluent using guppy fish (Poecilia reticulata) as an experimental model: a biomarker study.

Tannery wastewater in the East Calcutta Wetlands (a Ramsar site of West Bengal; number 1208) exerts adverse effects on commercial fish production and subsequently affects humans. The present study was conducted to investigate acute and chronic toxicity of tannery effluent on a fish biosystem by examining oxidative stress enzyme expression in different organs including liver, gills, and muscle following exposure. Phosphatases, both alkaline phosphatase and acid phosphatase, and antioxidant superoxide dismutase and catalase enzyme activities were determined in guppy fish (Poecilia reticulata) exposed to sublethal concentrations of composite tannery effluent. Data demonstrated that tannery effluent was capable of interfering with metabolic processes of fish by altering stress enzyme activities in fish organs, resulting in cellular injury. Data suggest that elevated activities of stress enzymes in fish upon exposure to environmental pollutants may serve as important biomarkers for oxidative stress.

Understanding the role of conserved proline and serine residues in the SARS-CoV-2 spike cleavage sites in the virus entry, fusion, and infectivity.

The spike (S) glycoprotein of the SARS-CoV-2 virus binds to the host cell receptor and promotes the virus's entry into the target host cell. This interaction is primed by host cell proteases like furin and TMPRSS2, which act at the S1/S2 and S2´ cleavage sites, respectively. Both cleavage sites have serine or proline residues flanking either the single or polybasic region and were found to be conserved in coronaviruses. Unravelling the effects of these conserved residues on the virus entry and infectivity might facilitate the development of novel therapeutics. Here, we have investigated the role of the conserved serine and proline residues in the SARS-CoV-2 spike mediated entry, fusogenicity, and viral infectivity by using the HIV-1/spike-based pseudovirus system. A conserved serine residue mutation to alanine (S2´S-A) at the S2´ cleavage site resulted in the complete loss of spike cleavage. Exogenous treatment with trypsin or overexpression of TMPRSS2 protease could not rescue the loss of spike cleavage and biological activity. The S2´S-A mutant showed no significant responses against E-64d, TMPRSS2 or other relevant inhibitors. Taken together, serine at the S2´ site in the spike protein was indispensable for spike protein cleavage and virus infectivity. Thus, novel interventions targeting the conserved serine at the S2´ cleavage site should be explored to reduce severe disease caused by SARS-CoV-2-and novel emerging variants. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03749-y.

Kennedy Epitope (KE)-dependent Retrograde Transport of Efficiently Cleaved HIV-1 Envelopes (Envs) and its Effect on Env Cell Surface Expression and Viral Particle Formation.

Efficiently cleaved HIV-1 Envs are the closest mimics of functional Envs as they specifically expose only bNAb (broadly neutralizing antibody) epitopes and not non-neutralizing ones, making them suitable for developing vaccine immunogens. We have previously identified several efficiently cleaved Envs from clades A, B, C and B/C. We also described that truncation of the CT (C-terminal tail) of a subset of these Envs, but not others, impairs their ectodomain conformation/antigenicity on the cell surface in a CT conserved hydrophilic domain (CHD) or Kennedy epitope (KE)-dependent manner. Here, we report that those Envs (4 - 2.J41 and JRCSF), whose native-like ectodomain conformation/antigenicity on the cell surface is disrupted upon CT truncation, but not other Envs like JRFL, whose CT truncation does not have an effect on ectodomain integrity on the cell surface, are also defective in retrograde transport from early to late endosomes. Restoration of the CHD/KE in the CT of these Envs restores wild-type levels of distribution between early and late endosomes. In the presence of retrograde transport inhibitor Retro 2, cell surface expression of 4 - 2.J41 and JRCSF Envs increases [as does in the presence of Rab7a DN and Rab7b DN (DN: dominant negative)] but particle formation decreases for 4 - 2.J41 and JRCSF Env pseudotyped viruses. Our results show for the first time a correlation between CT-dependent, CHD/KE regulated retrograde transport and cell surface expression/viral particle formation of these efficiently cleaved Envs. Based on our results we hypothesize that a subset of these efficiently cleaved Envs use a CT-dependent, CHD/KE-mediated mechanism for assembly and release from late endosomes.

Academic Radiology in the United States: Defining Gender Disparities in Faculty Leadership and Academic Rank.

RATIONALE AND OBJECTIVES: Female physicians in academic medicine have faced barriers that potentially affect representation in different fields and delay promotion. Little is known about gender representation differences in United States academic radiology departments, particularly within the most pursued subspecialties. PURPOSE: To determine whether gender differences exist in United States academic radiology departments across seven subspecialties with respect to academic ranks, departmental leadership positions, experience, and scholarly metrics. MATERIALS AND METHODS: In this cross-sectional study from November 2018 to June 2020, a database of United States academic radiologists at 129 academic departments in seven subspecialties was created. Each radiologist's academic rank, departmental leadership position (executive-level - Chair, Director, Chief, and Department or Division Head vs vice-level - vice, assistant, or associate positions of executive level), self-identified gender, years in practice, and measures of scholarly productivity (number of publications, citations, and h-index) were compiled from institutional websites, Doximity, LinkedIn, Scopus, and official NPI profiles. The primary outcome, gender composition differences in these cohorts, was analyzed using Chi2 while continuous data were analyzed using Kruskal-Wallis rank sum test. The adjusted gender difference for all factors was determined using a multivariate logistic regression model. RESULTS: Overall, 5086 academic radiologists (34.7% women) with a median 14 years of practice (YOP) were identified and indexed. There were 919 full professors (26.1% women, p < 0.01) and 1055 executive-level leadership faculty (30.6% women, p < 0.01). Within all subspecialties except breast imaging, women were in the minority (35.4% abdominal, 79.1% breast, 12.1% interventional, 27.5% musculoskeletal, 22.8% neuroradiology, 45.1% pediatric, and 19.5% nuclear; p < 0.01). Relative to subspecialty gender composition, women full professors were underrepresented in abdominal, pediatric, and nuclear radiology (p < 0.05) and women in any executive-level leadership were underrepresented in abdominal and nuclear radiology (p < 0.05). However, after adjusting for h-index and YOP, gender did not influence rates of professorship or executive leadership. The strongest single predictors for professorship or executive leadership were h-index and YOP. CONCLUSION: Women academic radiologists in the United States are underrepresented among senior faculty members despite having similar levels of experience as men. Gender disparities regarding the expected number of women senior faculty members relative to individual subspecialty gender composition were more pronounced in abdominal and nuclear radiology, and less pronounced in breast and neuroradiology. Overall, h-index and YOP were the strongest predictors for full-professorship and executive leadership among faculty. KEY RESULTS: ● Though women comprise 34.7% of all academic radiologists, women are underrepresented among senior faculty members (26.1% of full professors and 30.6% of executive leadership) ● Women in junior faculty positions had higher median years of practice than their male counterparts (10 vs 8 for assistant professors, 21 vs 13 for vice leadership) ● Years of practice and h-index were the strongest predictors for full professorship and executive leadership.

Dinitroaliphatics as linkers: application in the synthesis of novel artemisinin carba-dimer.

The versatility of nitroaliphatics is demonstrated by using it in the syntheses of artemisinin derived dimers. A few novel artemisinin derived dimer and monomer have been synthesized using nitroalkane as linker.

Artemisinin and its derivatives: a novel class of anti-malarial and anti-cancer agents.

In this tutorial review, an effort towards presentation of a comprehensive account of the recent developments on various kinds of artemisinin derivatives including artemisinin dimers, trimers and tetramers has been made and their efficacy towards malaria parasites and different cancer cells lines was compared with that of artemisinins, and various other anti-malarial and anti-cancer drugs. It is expected that this review will provide first-hand information on artemisinin chemistry to organic/medicinal chemists, and pharmacologists working on anticancer and anti-malarial drug development.

Bio-transformation of artemisinin using soil microbe: Direct C-acetoxylation of artemisinin at C-9 by Penicillium simplissimum.

Potent antimalarial compound artemisinin, 1 was bio-transformed to C-9 acetoxy artemisinin, 2 using soil microbe Penicillium simplissimum along with C-9 hydroxy derivative 3. The products were characterized using high field NMR and MS-MS data. The absolute stereochemistry of the newly generated chiral centers has been ascertained by COSY and 1D NOESY experiments. This is the first Letter of direct C-acetoxylation of artemisinin using microbial strains.

Lymphatic Anatomy and Physiology.

Lymphatics have long been overshadowed by the remainder of the circulatory system. Historically, lymphatics were difficult to study because of their small and indistinct vessels, colorless fluid contents, and limited effective interventions. However, the past several decades have brought increased funding, advanced imaging technologies, and novel interventional techniques to the field. Understanding the history of lymphatic anatomy and physiology is vital to further realize the role lymphatics play in most major disease pathologies and innovate interventional solutions for them.

Traumatic Chylothorax: Approach and Outcomes.

Traumatic chylothorax occurs more often now than in historic reports. In part, this is due to the increased ability to perform more advanced and aggressive thoracic resections and cardiovascular surgeries as well as the improved mortality of cancer patients. If untreated, chylothorax can result in significant morbidity and mortality, particularly in patients with underlying malignancy. Thoracic duct embolization for chylothorax was the first successful lymphatic intervention and has been performed for over 20 years. An overview of the clinical and technical approach to thoracic duct embolization for traumatic chylothorax is presented in addition to a review of outcomes.

Complications during Lymphangiography and Lymphatic Interventions.

Lymphangiography as a diagnostic procedure dates back to the 1950s and was widely performed for several decades until being supplanted by other advanced imaging techniques. With the advent of thoracic duct embolization to treat chylothorax, Constantin Cope ushered in a transition from lymphangiography as a diagnostic procedure to a precursor for lymphatic intervention. Subsequently, technical modifications and applications of lymphatic embolization to other medical conditions have greatly expanded the scope and application of lymphangiography and lymphatic intervention. Although there is increasing familiarity with lymphatic interventions, few interventionalists have performed a high enough volume to be aware of potential complications and their management. Potential complications of lymphangiography and those encountered while performing lymphatic interventions are discussed along with approaches to minimize their risk and management strategies should they occur.