Understanding the Driving Forces That Trigger Mutations in SARS-CoV-2: Mutational Energetics and the Role of Arginine Blockers in COVID-19 Therapy

SARS-CoV-2 is a global challenge due to its ability to mutate into variants that spread more rapidly than the wild-type virus. Because the molecular biology of this virus has been studied in such great detail, it represents an archetypal paradigm for research into new antiviral drug therapies. The rapid evolution of SARS-CoV-2 in the human population is driven, in part, by mutations in the receptor-binding domain (RBD) of the spike (S-) protein, some of which enable tighter binding to angiotensin-converting enzyme (ACE2). More stable RBD-ACE2 association is coupled with accelerated hydrolysis of furin and 3CLpro cleavage sites that augment infection. Non-RBD and non-interfacial mutations assist the S-protein in adopting thermodynamically favorable conformations for stronger binding. The driving forces of key mutations for Alpha, Beta, Gamma, Delta, Kappa, Lambda and Omicron variants, which stabilize the RBD-ACE2 complex, are investigated by free-energy computational approaches, as well as equilibrium and steered molecular dynamic simulations. Considered also are the structural hydropathy traits of the residues in the interface between SARS-CoV-2 RBD and ACE2 protein. Salt bridges and π-π interactions are critical forces that create stronger complexes between the RBD and ACE2. The trend of mutations is the replacement of non-polar hydrophobic interactions with polar hydrophilic interactions, which enhance binding of RBD with ACE2. However, this is not always the case, as conformational landscapes also contribute to a stronger binding. Arginine, the most polar and hydrophilic among the natural amino acids, is the most aggressive mutant amino acid for stronger binding. Arginine blockers, such as traditional sartans that bear anionic tetrazoles and carboxylates, may be ideal candidate drugs for retarding viral infection by weakening S-protein RBD binding to ACE2 and discouraging hydrolysis of cleavage sites. Based on our computational results it is suggested that a new generation of “supersartans”, called “bisartans”, bearing two anionic biphenyl-tetrazole pharmacophores, are superior to carboxylates in terms of their interactions with viral targets, suggesting their potential as drugs in the treatment of COVID-19. In Brief: This in silico study reviews our understanding of molecular driving forces that trigger mutations in the SARS-CoV-2 virus. It also reports further studies on a new class of “supersartans” referred to herein as “bisartans”, bearing two anionic biphenyltetrazole moieties that show potential in models for blocking critical amino acids of mutants, such as arginine, in the Delta variant. Bisartans may also act at other targets essential for viral infection and replication (i.e., ACE2, furin cleavage site and 3CLpro), rendering them potential new drugs for additional experimentation and translation to human clinical trials.     

Detection of HBV-DNA in liver biopsy and serum: its significance in the selection of hepatitis B patients for antiviral therapy

We have characterized the hepatitis B virus state in liver and serum of 38 HBsAg-positive chronic hepatitis patients (chronic active hepatitis (CAH), 19; chronic persistent hepatitis (CPH), 7; cirrhosis, 11; 'normal' carrier, 1) and 21 HBsAg-negative patients. Episomal HBV-DNA in liver, without detectable integrated HBV-DNA sequences, concomitant with HBV-DNA in serum was found in 19 HBeAg-positive patients (CAH, 16; CPH, 1; cirrhosis, 2). Integrated sequences were detected in 13 HBsAg-positive HBeAg-negative patients (CAH, 1; CPH, 5; cirrhosis, 7) and in 1 HBsAg-negative patient. Episomal HBV-DNA and integrated HBV-DNA sequences were observed simultaneously in 1 HBsAg-positive HBeAg-negative CPH patient and in 4 HBsAg-positive cirrhosis patients (2 HBeAg-positive, 2 HBeAg-negative). The presence of HBcAg immunofluorescence corresponded well with that of episomal HBV-DNA. Antiviral therapy is advised for HBsAg-positive chronic hepatitis patients with episomal HBV-DNA, irrespective of the presence of integrated sequences. Since the presence of episomal HBV-DNA in liver is not always accompanied by the presence of serum HBV-DNA, procedures for the selection and evaluation of patients for antiviral therapy should be extended by characterization of the HBV-DNA state in liver biopsies.     

Predictive validity of DSM‐IV oppositional defiant and conduct disorders in clinically referred preschoolers

Background: Diagnostic validity of oppositional defiant and conduct disorders (ODD and CD) for preschoolers has been questioned based on concerns regarding the ability to differentiate normative, transient disruptive behavior from clinical symptoms. Data on concurrent validity have accumulated, but predictive validity is limited. Predictive validity is critical to refuting the hypothesis that diagnosing ODD and CD in young children leads to pathologizing normal behavior. ODD and CD have emerged as gateway disorders to many forms of adult psychopathology. Establishing how early we can identify symptoms and disorders that herald poor prognosis is one of the most important goals for research on etiology and prevention. Methods: Subjects were 3–5‐year‐old consecutive referrals to a child psychiatry clinic (n = 123) and demographically matched children from a pediatric clinic (n = 100). A diagnostic interview was used to assess DSM‐IV ODD and CD in a prospective follow‐up design from preschool to school age. Stability of ODD and CD diagnoses and level of impairment were tested as a function of preschool diagnosis. Results: Over 80% of preschoolers diagnosed with ODD and approximately 60% of preschoolers diagnosed with CD met criteria for the same disorder during follow‐up. Impairment over time varied significantly as a function of stability of diagnosis across three years. Conclusions: These results provide the first evidence of the predictive validity of DSM‐IV ODD and CD in clinically referred preschool children. The findings challenge the assumption that symptoms of disruptive behavior disorders that occur during the preschool period tend to be transient.     

Advance provision of emergency contraception for pregnancy prevention: a meta-analysis

OBJECTIVE: Advance provision of emergency contraception can circumvent some obstacles to timely use. We performed a meta-analysis to summarize randomized controlled trials evaluating advance provision of emergency contraception to explore effects on pregnancy rates, sexually transmitted infections, and sexual and contraceptive behaviors. DATA SOURCES: In August 2006, we searched CENTRAL, EMBASE, POPLINE, MEDLINE, a specialized emergency contraception article database, and contacted experts to identify published or unpublished trials. METHODS OF STUDY SELECTION: We included randomized controlled trials comparing advance provision to standard access, defined as any of the following: counseling (with or without information about emergency contraception) or provision of emergency contraception on request at a clinic or pharmacy. TABULATION, INTEGRATION AND RESULTS: Two reviewers independently assessed study quality. We performed a meta-analysis using Review Manager software. Eight randomized controlled trials met inclusion criteria, representing 6,389 patients in the United States, China, and India. Advance provision did not decrease pregnancy rates, despite increased use (single use, odds ratio [OR] 2.52, 95% confidence interval [CI] 1.72-3.70; multiple use: OR 4.13, 95% CI 1.77-9.63) and faster use (weighted mean difference -14.6 hours, 95% CI -16.77 to -12.4 hours). Advance provision did not increase rates of sexually transmitted infections (OR 0.99, 95% CI 0.73-1.34), unprotected intercourse, or changes in contraceptive methods. Women who received emergency contraception in advance were as likely to use condoms as other women. CONCLUSION: Advance provision of emergency contraception did not reduce pregnancy rates and did not negatively affect sexual and reproductive health behaviors and outcomes compared with conventional provision. LEVEL OF EVIDENCE: III.     

拘束冷应激对大鼠肾脏热休克蛋白表达和血清皮质醇含量的动态影响

目的：研究拘束冷应激对大鼠肾脏组织热休克蛋白（heat shock protein 70,HSP70）表达和血清中皮质醇（Cortisol,CORT）含量的动态影响及可能的机制。方法：选取50日龄清洁级大鼠77只,随机分为7组,即0、0.5、1.0、1.5、2.0、2.5和3.0 h。采用拘束冷应激法,应激相应时间后,用免疫组织化学方法观察大鼠肾脏组织HSP70的表达,并检测血清中CORT含量。结果：血清中的CORT浓度在1.5 h呈现最高值,其余各时点变化不明显。光镜下可见HSP70在肾小球毛细血管内皮细胞的胞核及肾小管上皮细胞的胞核和胞浆中均有表达。肾脏中HSP70的表达首先呈增加的趋势,1.5～2.5 h HSP70持续高表达（P〈0.01）,之后下降（P〈0.05）。结论：适当强度的拘束冷应激能诱导肾脏组织中HSP70的合成,并且随着时间的延长而增加,但过度的拘束冷应激则可能降低或阻断肾脏HSP70的表达。     

Undifferentiated carcinoma with osteoclastic giant cells (UCOCGC) of the pancreas associated with the familial atypical multiple mole melanoma syndrome (FAMMM)

The familial atypical multiple mole melanoma (FAMMM) syndrome is caused by a germline mutation of p16. More than 90% of the sporadic pancreatic carcinomas contain genetic alterations that inactivate p16. Patients with the FAMMM syndrome have an increased risk of developing pancreatic cancer. Ductal adenocarcinoma is the most common cancer of the pancreas and the one encountered in patients with FAMMM syndrome. Undifferentiated carcinoma with osteoclastic giant cells, also referred to as UCOCGC of the pancreas, is a rare variant of pancreatic cancer. An UCOCGC of the pancreas associated with FAMMM syndrome is described in this report. Molecular analysis confirmed a germline p16-Leiden deletion in the UCOCGC, accompanied by somatic loss of heterozygosity of the second p16 allele, and absence of p16 protein expression in the neoplastic cells. It is the first case reported and it provides additional evidence that UCOCGC can be considered as a variant of conventional ductal adenocarcinoma of the pancreas.