Vertical mother-to-infant transmission of herpes simplex virus 2 is correlated with tropism due to mutations in viral UL13.

Although neonates are commonly exposed to vaginal herpes simplex virus (HSV)-2, neonatal herpes is rare. Therefore, we analyzed paired infant and maternal HSV-2 isolates from two cases of mother-to-infant transmission to identify viral factors contributing to vertical transmission. Sixteen infant isolates with neonatal herpes and 27 genital isolates in their third trimester were included. The infant isolates were significantly more temperature-independent than the maternal isolates. Sequence comparison revealed viral UL13 protein kinase (UL13-PK) mutation in the infant isolates in both cases. In the expanded cohort, infant isolates (5/18) had significantly more UL13-PK mutations than genital isolates (1/29). Isolates within 8 days post-birth (3/4) had a significantly higher frequency of UL13-PK mutation than those after 9 days (2/14), suggesting a close association between UL13-PK mutations and vertical transmission. Elongation factor 1-delta was identified as a target of UL13-PK by proteomic analysis of UL13-PK-positive and -negative HepG2 cells. The mixed infant isolates with the intact and mutated UL13-PK conferred altered cell tropism, temperature independence adapting to fetal temperature, and better growth properties in Vero and hepatoblastoma HepG2 cells than in HSV-2 with intact and mutated UL13-PK alone, indicating that viral UL13-PK mutation is essential for vertical HSV-2 transmission.

Widespread spontaneous spinal epidural hematoma treated with a combined technique using a flexible neuroendoscope after hemilaminectomy: A case report.

Background: One-third of spinal epidural hematomas occur spontaneously, and these may be associated with the acute onset of severe paralysis. Here, we present a case of T4-L4 symptomatic spontaneous spinal epidural hematoma which was successfully removed using a flexible neuroendoscope after hemilaminectomy. Case Description: Using flexible neuroendoscopy, we successfully treated a T4-L4 spinal epidural hematoma in an 89-year-old Japanese female who spontaneously developed back pain and paraparesis. The hematoma was removed utilizing a hemilaminectomy at three vertebral levels (T11, T12, and L1), while the remaining hematoma debris was completely evacuated with flexible neuroendoscopy. Neurological improvement was observed immediately postsurgery. Conclusion: Flexible neuroendoscopy provided a less extensive surgical method for removing a T4-L4 spontaneous epidural hematoma.

Ruptured proximal middle cerebral artery traumatic pseudoaneurysm treated with bypass-assisted trapping surgery: A case report.

Background: Traumatic pseudoaneurysms are rare but have a high mortality rate; therefore, immediate diagnosis is vital. Most pseudoaneurysms are in the internal carotid artery or peripheral arteries, while proximal middle cerebral artery pseudoaneurysms have rarely been reported. We present a case of ruptured traumatic pseudoaneurysm located at the M1-M2 bifurcation. Case Description: A 42-year-old man was injured in a motorcycle accident and his Glasgow coma scale score on admission was 7 (Eye opening1, Verbal response2, Motor response4 [E1V2M4]). Head computed tomography (CT) showed thick subarachnoid hemorrhage (SAH). We suspected a ruptured aneurysm, but three-dimensional CT angiography (3D-CTA) did not detect any vascular defects. Head magnetic resonance angiography showed progressive right M1 stenosis suggesting arterial dissection. 3D-CTA on day 20 showed a small aneurysm in the proximal portion of the M2. Although surgery was scheduled for day 26, suddenly left hemiparesis appeared on day 24. Head CT detected fresh SAH and emergency surgery was performed on day 25. We dissected around the ruptured point under M1 temporary occlusion with superficial temporal artery-M2 assist bypass. Contrary to our expectations, there was only a small laceration in the right M2 superior trunk. We trapped the laceration and the proximal portion of the M2 superior trunk while preserving antegrade blood flow from the M1 to the M2 inferior trunk. On the 5-month follow-up, the patient was able to walk independently. Conclusion: Unreasonably thick traumatic SAH or spastic stenosis after head injury may indicate a traumatic pseudoaneurysm and require repeated neurovascular evaluation. If a pseudoaneurysm is detected, immediate surgical intervention is mandatory.

A case of middle cerebral artery large circumferential aneurysm treated with bypass-assisted trapping surgery.

M1 large circumferential aneurysms are clinically challenging because they cannot be treated by simple neck clipping and they may involve the lenticulostriate arteries (LSAs). Although some reports have described endovascular and direct surgical treatment of these aneurysms, the optimal treatment approach remains uncertain. We report a case involving a ruptured large M1 circumferential aneurysm that was treated with bypass-assisted trapping surgery and showed favorable outcomes. The patient was a 47-year-old man presenting with subarachnoid hemorrhage. Digital subtraction angiography revealed a large circumferential aneurysm in the right middle cerebral artery M1 segment with involvement of the lateral and medial LSAs. We successfully performed trapping surgery with the assistance of a superficial temporal artery (STA)-M2 bypass while preserving the medial and lateral LSAs. Although left hemiparesis caused by medial LSA thrombosis appeared in the early postoperative period, the patient showed good recovery from symptoms with rehabilitation and could independently perform daily activities at the five-month follow-up. The treatment of M1 large circumferential aneurysms should involve considerations for prevention of rebleeding, blood supply to the distal area, and preservation of perforating arteries. The treatment strategy for this challenging aneurysm should be planned based on the patient's condition and individual anatomy.

Butein inhibits corticosterone-induced apoptosis of Neuro2A cells by maintaining MEK-ERK signaling.

Stress-induced overactivation of glucocorticoid signaling may contribute to mental illness by inducing neuronal death and dysfunction. We previously reported that pretreatment with the plant flavonoid butein inhibits corticosterone (CORT)-induced apoptosis of Neuro2A (N2A) cells. In the current study, we examined whether MEK-ERK and PI3K-AKT signaling pathways are involved in neuroprotection by butein. N2A cells were pre-incubated with serum-free DMEM containing 0.5 µM butein for 30 min, and then incubated with serum-free DMEM containing 0.5 µM butein, 50 µM CORT, 50 µM LY294002, or 50 µM PD98059 as indicated for 24 h. We subsequently performed the MTT assay and the western blot analysis. As expected, CORT considerably reduced N2A cell viability and increased relative expression of the apoptosis effector cleaved caspase-3, whereas pretreatment with butein blocked these cytotoxic effects. Treatment with CORT alone also decreased both AKT and ERK protein phosphorylation. Butein pretreatment had no effect on AKT phosphorylation, and only partially reversed the reduction in phosphorylated ERK. However, cotreatment with butein and the PI3K inhibitor LY294002 during CORT exposure enhanced ERK phosphorylation, whereas cotreatment with butein and the ERK phosphorylation/activation inhibitor PD98059 enhanced AKT phosphorylation, suggesting that MEK-ERK negatively regulates AKT phosphorylation. Moreover, the protective efficacy of butein was blocked by PD98059 cotreatment but not LY294002 cotreatment. These findings suggest that butein protects neurons against glucocorticoid-induced apoptosis by sustaining ERK phosphorylation and downstream signaling.

Catastrophic Propeller Brain Injury with Large Scalp Defect Treated with Omental Flap.

In this study, we report a case of catastrophic propeller brain injury with large scalp defect treated with omental flap reconstruction. A 62-year-old man was accidentally caught in a powered paraglider propeller during maintenance. The rotor blades impacted the left part of his head. On arrival at the hospital, he presented with a Glasgow Coma Scale score of E4V1M4. On some areas on his head, skin was noticeably cut off, and the brain tissue out-slipped through an open skull fracture. Continuous bleeding from the superior sagittal sinus (SSS) and the brain surface was observed during emergency surgery. Massive bleeding from the SSS was controlled using a number of tenting sutures and hemostatic agents. We evacuated the crushed brain tissue and coagulated the severed middle cerebral arteries. Dural plasty using the deep fascia of the thigh was performed. The skin defect was closed using an artificial dermis. The administration of high-dose antibiotics has failed to prevent meningitis. Moreover, the severed skin edges and fasciae were necrotic. Plastic surgeons performed debridement and vacuum-assisted closure therapy to promote wound healing. Follow-up head computed tomography revealed hydrocephalus. Lumbar drainage was performed; however, sinking skin flap syndrome was observed. After removing the lumbar drainage, cerebrospinal fluid leakage occurred. We then performed cranioplasty with a titanium mesh and omental flap on day 31. After the surgery, perfect wound healing and infection control were achieved; however, severe disturbance of consciousness remained. The patient was transferred to a nursing home. Primary hemostasis and infection control are mandatory. An omental flap has been determined to be effective in controlling infection by covering the exposed brain tissue.

Rare Dilated Collateral Circulation from Accessory Meningeal Artery to Inferolateral Trunk: A Case Report.

The accessory meningeal artery (AMA) demonstrates various potential anastomoses with the external (ECA) and internal (ICA) carotid arteries. However, rarely does the AMA markedly dilate and compensate for ICA blood flow. A 52-year-old woman with nonspecific symptoms was diagnosed with multiple cerebral aneurysms and abnormal blood vessels observed on magnetic resonance angiography. Digital subtraction angiography revealed four aneurysms and anastomoses between the left AMA and inferolateral trunk (ILT). In addition, two sequential severe flexions were observed in the cervical portion of the left ICA. No ischemic lesions were detected on magnetic resonance imaging. In conclusion, we experienced a rare case in which the AMA-ILT anastomosis was highly developed. This case also presented with the unusual characteristics of an anomaly in the extracranial ICA and multiple aneurysms.

A case of symptomatic carotid artery occlusion after aortic arch replacement treated with carotid-carotid crossover bypass.

Background: Symptomatic common carotid artery (CCA) occlusion is rare and its treatment remains unestablished. Although cases of subclavian-to-carotid bypass have been reported, very few cases of carotid-tocarotid crossover bypass have been reported, despite its advantages. We report a case of Riles type 1A symptomatic CCA occlusion after aortic arch replacement that was treated with carotid-to-carotid crossover bypass with favorable outcomes. Case Description: A 65-year-old woman with a history of hypertension, hyperlipidemia, diabetes, and total arch replacement for thoracic aortic aneurysm was admitted to our hospital with a complaint of the right hemiparesis and motor aphasia. Head magnetic resonance imaging revealed a fresh infarction in the left cerebral hemisphere. Cervical computed tomography (CT) angiography revealed left CCA occlusion. Thoracic CT angiography showed severe stenosis of the left subclavian artery. SPECT showed a general decrease in blood flow in the left cerebral hemisphere. We performed a carotid-to-carotid crossover bypass with a synthetic graft that was passed through the subcutaneous tunnel. First, the right carotid artery-synthetic graft end-to-side anastomosis was performed. Subsequently, we performed synthetic graft-left CCA end-to-side anastomosis. The postoperative course was uneventful. Cervical computed tomography angiography showed perfect patency of the crossover bypass. The patient recovered almost completely and was independently performing daily activities. Conclusion: Carotid-to-carotid crossover bypass is a durable treatment for symptomatic CCA occlusion. Further studies are needed to compare its outcomes with those of other methods and to confirm our findings with larger sample size.

A Case of Proximal Posterior Inferior Cerebellar Artery (PICA) Aneurysm Treated with PICA-to-PICA Bypass and Trapping Surgery: Comparison with Occipital Artery-PICA Bypass.

Posterior inferior cerebellar artery (PICA) aneurysms often require cerebral vascular reconstruction for surgical treatment because of their characteristic morphology. Despite its potential complications, the occipital artery-to-posterior inferior cerebellar artery (OA-PICA) bypass is a typical treatment because of its versatility. Although a few cases of intracranial-to-intracranial bypass have been reported, this type of vascular reconstruction is only regarded as an alternative to the OA-PICA bypass because of the uncertainty of bypass feasibility and potential risk of ischemic complications. In this article, we report a case of proximal PICA ruptured aneurysm that was treated with a PICA-to-PICA (PICA-PICA) bypass. A 79-year-old man presented with a chief complaint of sudden, severe headache and disturbances in consciousness. Radiological examination revealed a right proximal PICA fusiform aneurysm. The patient had many systemic disorders such as microscopic polyangiitis and steroid-induced diabetes mellitus that could have caused wound dehiscence and cerebrospinal fluid (CSF) leakage. We performed the PICA-PICA bypass and trapping surgery rather than the OA-PICA bypass to avoid skin problems and CSF leakage. The postoperative course was uneventful, and the patient was discharged on day 64 without any neurological disorders. In comparison with the OA-PICA bypass, the PICA-PICA bypass is less likely to cause CSF leakage and skin complications, although it carries the risk of specific ischemic complications and requires advanced surgical techniques. For some patients with systemic disorders, the PICA-PICA bypass could be an optimal treatment option for proximal fusiform PICA aneurysms rather than as an alternative to the OA-PICA bypass.

Antiviral therapy for COVID-19: Derivation of optimal strategy based on past antiviral and favipiravir experiences.

Favipiravir, a broad-spectrum RNA-dependent RNA polymerase inhibitor, inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at significantly lower concentrations than the plasma trough levels achieved by the dosage adopted for influenza treatment and exhibits efficacy against coronavirus disease 2019 (COVID-19) pneumonia. Although high doses of favipiravir are required due to the molecule being a purine analog, its conversion into the active form in infected cells with active viral RNA synthesis enhances the antiviral specificity and selectivity as a chain terminator with lethal mutagenesis. Another characteristic feature is the lack of generation of favipiravir-resistant virus. COVID-19 pneumonia is caused by strong cell-mediated immunity against virus-infected cells, and the inflammatory response induced by adaptive immunity continues to peak for 3 to 5 days despite antiviral treatment. This has also been observed in herpes zoster (HZ) and cytomegalovirus (CMV) pneumonia. Inflammation due to an immune response may mask the effectiveness of favipiravir against COVID-19 pneumonia. Favipiravir significantly shortened the recovery time in patients with mild COVID-19 pneumonia by 3 days with the start of treatment by the 5th day of symptom onset. Since both CMV and COVID-19 pneumonia are caused by adaptive immunity and prevention of cytomegalovirus pneumonia is the standard treatment due to difficulties in treating refractory CMV pneumonia, COVID-19 pneumonia should be prevented with early treatment as well. In the present study, we have comprehensively reviewed the optimal antiviral therapy for COVID-19 based on clinical trials of favipiravir for the treatment of COVID-19 pneumonia and the concurrently established therapies for other viral infections, particularly HZ and CMV pneumonia. Optimally, antivirals should be administered immediately after COVID-19 diagnosis, similar to that after influenza diagnosis, to prevent COVID-19 pneumonia and complications resulting from microangiopathy.

The Interferon-Inducible Human PLSCR1 Protein Is a Restriction Factor of Human Cytomegalovirus.

Human phospholipid scramblase 1 (PLSCR1) is strongly expressed in response to interferon (IFN) treatment and viral infection, and it has been suggested to play an important role in IFN-dependent antiviral responses. In this study, we showed that the levels of human cytomegalovirus (HCMV) plaque formation in OUMS-36T-3 (36T-3) cells with high basal expression of PLSCR1 were significantly lower than those in human embryonic lung (HEL) cells with low basal expression of PLSCR1. In addition, the levels of HCMV plaque formation and replication in PLSCR1-knockout (KO) 36T-3 cells were significantly higher than those in parental 36T-3 cells and were comparable to those in HEL cells. Furthermore, compared to that in PLSCR1-KO cells, the expression of HCMV major immediate early (MIE) proteins was repressed and/or delayed in parental 36T-3 cells after HCMV infection. We also showed that PLSCR1 expression decreased the levels of the cAMP-responsive element (CRE)-binding protein (CREB)•HCMV immediate early protein 2 (IE2) and CREB-binding protein (CBP)•IE2 complexes, which have been suggested to play important roles in the IE2-mediated transactivation of the viral early promoter through interactions with CREB, CBP, and IE2. Interestingly, PLSCR1 expression repressed CRE- and HCMV MIE promoter-regulated reporter gene activities. These observations reveal, for the first time, that PLSCR1 negatively regulates HCMV replication by repressing the transcription from viral MIE and early promoters, and that PLSCR1 expression may contribute to the IFN-mediated suppression of HCMV infection. IMPORTANCE Because several IFN-stimulated genes (ISGs) have been reported to suppress HCMV replication, HCMV replication is thought to be regulated by an IFN-mediated host defense mechanism, but the mechanism remains unclear. PLSCR1 expression is induced in response to viral infection and IFN treatment, and PLSCR1 has been reported to play an important role in IFN-dependent antiviral responses. Here, we demonstrate that HCMV plaque formation and major immediate early (MIE) gene expression are significantly increased in PLSCR1-KO human fibroblast cells. PLSCR1 reduces levels of the CREB•IE2 and CBP•IE2 complexes, which have been suggested to play important roles in HCMV replication through its interactions with CREB, CBP, and IE2. In addition, PLSCR1 expression represses transcription from the HCMV MIE promoter. Our results indicate that PLSCR1 plays important roles in the suppression of HCMV replication in the IFN-mediated host defense system.

Emergence of varicella-zoster virus resistance to acyclovir: epidemiology, prevention, and treatment.

Introduction: Acyclovir has led to the development of successful systemic therapy for herpes simplex virus and varicella-zoster virus (VZV) infection, and the use of valacyclovir and famciclovir has improved treatment. Additionally, the use of a helicase-primase (HP) inhibitor (HPI), amenamevir, is changing the treatment of herpes zoster (HZ).Area covered: VZV infection is prevented by vaccines and is treated with antiviral agents. Acyclovir and penciclovir are phosphorylated by viral thymidine kinase and work as chain terminators. Improvements in the management of immunocompromised patients have reduced severe and prolonged immunosuppression and chronic VZV infection with acyclovir-resistant mutants has become rarer. The HP is involved in the initial step of DNA synthesis and amenamevir has novel mechanisms of action, efficacy to acyclovir-resistant mutants, and pharmacokinetic characteristics. The literature search for PUBMED was conducted on 10 April 2020 and updated on 4 November 2020.Expert opinion: Amenamevir has been used to treat HZ in Japan. Although the number of patients with VZV infection will decrease owing to the use of vaccines, the addition of HPI will improve treatment and treatment options for resistant viruses. The clinical use of HPIs in addition to current nucleoside analogs opens a new era of antiherpes therapy.

Viral ribonucleotide reductase attenuates the anti-herpes activity of acyclovir in contrast to amenamevir.

Amenamevir is a helicase-primase inhibitor of herpes simplex virus (HSV) and varicella-zoster virus (VZV) and is used for the treatment of herpes zoster in Japan. The half maximal effective concentrations (EC50s) of acyclovir and sorivudine for VZV increased as the time of treatment was delayed from 6 to 18 h after infection, while those of amenamevir and foscarnet were not affected. Susceptibility of infected cells at 0 and 18 h after infection was examined with four anti-herpes drugs, and the fold increases in EC50 for acyclovir, sorivudine, amenamevir, and foscarnet were 13.1, 6.3, 1.3, and 1.0, respectively. The increase in the EC50s for acyclovir in the late phase of infection in VZV and HSV was abolished by hydroxyurea, a ribonucleotide reductase (RR) inhibitor. The common mechanism affecting antiviral activities of acyclovir to HSV and VZV was examined in HSV-infected cells. The amount of HSV DNA in cells treated with amenamevir at 10 x EC50 was similar at 0 and 12 h but less than that in cells treated with acyclovir at 10 x EC50. dGTP, produced through viral RR, peaked at 4 h and decreased thereafter as it was consumed by viral DNA synthesis. Because acyclovir and amenamevir inhibited viral DNA synthesis, thus making dGTP unnecessary, dGTP was significantly more abundant in the presence of acyclovir and amenamevir than in untreated, infected cells. Abundant dGTP supplied by RR may compete with acyclovir triphosphate and attenuate its antiviral activity. In contrast, abundant dGTP did not influence the inhibitory action of amenamevir on viral helicase-primase activity. ATP was significantly decreased at 12 h after infection and significantly more abundant in untreated infected cells compared to cells treated with acyclovir and amenamevir. The anti-herpetic activity of amenamevir was not affected by the replication cycle of VZV and HSV, indicating the suitability of amenamevir for the treatment of herpes zoster and suppressive therapy for genital herpes.

The anti-human cytomegalovirus drug tricin inhibits cyclin-dependent kinase 9.

4',5,7-trihydroxy-3',5'-dimethoxyflavone (tricin), derived from Sasa albo-marginata, has been reported to suppress significantly human cytomegalovirus (HCMV) replication in human embryonic lung (HEL) fibroblast cells. However, the target protein of tricin remains unclear. This study focused on the anti-HCMV activity of tricin in terms of its binding affinity to cyclin-dependent kinase 9 (CDK9). A molecular docking study predicted that tricin binds well to the ATP-binding site of CDK9. Experimental measurements then revealed that tricin inhibits the kinase activity of CDK9 and affects the phosphorylation of the carboxy-terminal domain of RNA polymerase II. Based on these results, we conclude that CDK9 is one of the target proteins of tricin. We also found that tricin possesses anti-HCMV activity with no cytotoxicity against HEL cells.

Tricin inhibits the CCL5 induction required for efficient growth of human cytomegalovirus.

Treatment of human embryonic lung fibroblast (HEL) cells with tricin (4', 5, 7-trihydroxy-3', 5'-dimethoxyflavone) following infection with human cytomegalovirus (HCMV) reportedly significantly suppresses HCMV replication. In the present work, the mechanisms for the anti-HCMV effects of tricin in HEL cells were examined. It was found that exposure of HEL cells to tricin inhibited HCMV replication, with concomitant decreases in amounts of transcripts of the CC chemokine RANTES (CCL5)-encoding gene and in expression of the CCL5 protein. It was also found that transcripts of HCMV immediate early 1 (IE1), and HCMV UL54 (encoding DNA polymerase) and replication of HCMV was significantly lower in CCL5 gene-knockdown cells. These results suggest that the anti-HCMV activity of tricin differs from that of ganciclovir and that CCL5 is one of the chemokines involved in HCMV replication. In addition, it is possible that chemokine CCL5 is one of the targets of tricin.

An in silico-designed flavone derivative, 6-fluoro-4'-hydroxy-3',5'-dimetoxyflavone, has a greater anti-human cytomegalovirus effect than ganciclovir in infected cells.

A novel type of antiviral agent for human cytomegalovirus (HCMV) is required, because the appearance of ganciclovir (GCV) resistant viruses has been reported. Tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) has been shown to suppress significantly HCMV replication in human embryonic lung (HEL) fibroblast cells. Recently, we revealed that the action of tricin is different from that of GCV and cyclin-dependent kinase 9 (CDK9) is one of the target proteins of tricin. These results suggested that tricin is considered as a novel type of anti-HCMV agent. However, its anti-HCMV potency is not greater than that of GCV. This study tried to develop novel compounds with much greater anti-HCMV activity than GCV. We first made modifications to tricin by introducing fluorine atom, and then performed molecular docking simulations using the designed compounds and CDK9. The calculated binding energies showed that 6F-tricin (6-fluoro-4'-hydroxy-3',5'-dimetoxyflavone) binds to CDK9 much stronger than tricin. Based on these results, 6F-tricin was synthesized, and then its anti-HCMV effect was analyzed in HEL cell cultures. As a result, 6F-tricin strongly suppressed HCMV replication in a dose-dependent manner. The anti-HCMV activity with a 50% effective concentration (EC50) was 0.126 nM, corresponding to about 1/200 and 1/400 of EC50 of GCV (27.5 nM) and tricin (54.3 nM), respectively. Moreover, 6F-tricin had no cytotoxicity against HEL cells at concentrations up to 10 µM. We further performed detailed analysis on the amino acid contributions to the binding energies and found that the strong binding affinity for 6F-tricin to CDK9 is attributed to the specific binding orientation of 6F-tricin in the ATP-binding site. These results suggest that 6F-tricin is a promising candidate for anti-HCMV drug development.

[Cerebrospinal fluid leakage and abducens nerve palsy caused by bowling activity].

Cerebrospinal fluid leakage can develop due to traffic trauma or lumbar puncture; however, in many cases, it develops spontaneously without any obvious cause. This report describes a case of cerebrospinal fluid leakage caused by bowling activity. A 57-year-old woman adjusted her bowling form, which led to the development of an orthostatic headache and double vision. Cerebrospinal fluid leakage and right abducens nerve palsy was diagnosed, which was resistant to conservative treatment. An epidural blood patch was performed, leading to an improvement in the headache and abducens nerve palsy. The hypotension and nerve palsy may have been caused by small amounts of cerebrospinal fluid leakage due to repeated traction of the brachial plexus and nerve root resulting from an irregular bowling form. To the best of our knowledge, there are no reported cases of cerebrospinal fluid leakage caused by bowling; therefore, this is a valuable case to investigate the mechanism of onset. Similar mechanisms may have remained undiscovered in other cases of spontaneous intracranial hypotension.

Characterization of susceptibility variants of poliovirus grown in the presence of favipiravir.

BACKGROUND: T-705 (favipiravir) is a potent inhibitor of RNA-dependent RNA polymerases of influenza viruses and no favipiravir-resistant virus has been isolated. Poliovirus RNA polymerase has been well characterized and isolation of resistant virus was examined in poliovirus. METHODS: Susceptibility variants of poliovirus I (Sabin strain) were isolated during passages in the presence of favipiravir and characterized for their susceptibility and the sequence of RNA polymerase. RESULTS: Five variants with 0.47-1.88 times the 50% inhibitory concentration for plaque formation of the parent poliovirus had amino acid variations in the 3D gene of the RNA polymerase. The distribution of amino acid variations was not related to ribavirin resistance, and two amino acid variation sites were found near the finger domain. CONCLUSION: Favipiravir as a chain terminator would not be incorporated and replicate to cause lethal mutagenesis as a mutagen like ribavirin, and resistant mutants were not isolated. A high replication level would generate mutations leading to favipiravir resistance as ribavirin resistance was generated, but generated mutations would be lethal to the RNA polymerase function.

Inhibition of human cytomegalovirus replication by tricin is associated with depressed CCL2 expression.

We previously reported that treatment with tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) after human cytomegalovirus (HCMV) infection significantly suppressed both infectious virion production and HCMV replication in human embryonic lung fibroblast (HEL) cells. Moreover, we recently demonstrated that HCMV infection can increase the expression of CC-motif ligand 2 (CCL2/MCP-1) and of CCR2, a CCL2-specific receptor, effects that can in turn enhance HCMV infection and replication. Hence, we here examined whether the CCL2-CCR2 axis is involved in the anti-HCMV effects of tricin in HEL cells. Tricin exposure yielded dose-dependent decreases in the accumulation of transcripts for the HCMV immediate early gene and the DNA polymerase gene in HCMV-infected cells, along with decreased production of infectious HCMV. Concomitantly, tricin caused dose-dependent attenuation of HCMV infection-induced up-regulation of expression of CCL2 and CCR2 mRNAs and of CCL2 protein. Moreover, CCL2 reversed tricin-mediated inhibition of HCMV virion production in a dose-dependent manner. Thus, tricin appears to exert anti-HCMV activity by depressing CCL2 expression.