Pituitary surgery and COVID.

An effect of the COVID-19 pandemic was the disruption of healthcare systems, especially surgical services provided to the community. Pituitary surgery was especially impacted, given the majority of cases were deemed non-urgent with very few exceptions, and the high risk of viral transmission conferred by the endoscopic endonasal transsphenoidal approach. Patients suffering from pituitary lesions with resultant endocrinopathy or visual symptoms saw their treatment delayed or altered, which had implications on their outcomes and care. This disruption extended to surgical training and the usual functioning of academic units, necessitating changes to curricula and implementation of novel methods of progressing surgical education. This review will explore the effect of the COVID pandemic on pituitary surgery, the experiences of various surgeons as well as the adaptations implemented on the frontlines. The lessons learned from the experience of the pandemic may assist specialists in gleaning insights regarding the care of patients in the future.

Subdural Versus Subgaleal Drain Placement After Minicraniotomy for Chronic Subdural Hematoma.

BACKGROUND AND OBJECTIVES: Surgical evacuation with placement of a postoperative drain is the standard treatment for symptomatic chronic subdural hematoma (cSDH). Subdural and subgaleal drains are equally effective after burrhole craniostomy, but the optimal location of the drain after craniotomy is not clear. We sought to compare the clinical and radiological outcomes of subdural and subgaleal drain placement in patients undergoing minicraniotomy for cSDH. METHODS: A retrospective review of 137 consecutive patients undergoing minicraniotomy for cSDH at a single institution was performed. Cases were stratified by location of postoperative drain. The primary outcome was change in functional status (modified Rankin Score, mRS) at 3 months from preoperative baseline. RESULTS: Among the patient cohort, 24.6% received subgaleal drain placement. After a median follow-up of 105 days, 79.4% (27/34) in the subgaleal group and 57.3% (59/103) in the subdural group (P = .02) had been discharged home. Worse premorbid mRS (P = .002), subdural drain location (P = .004), and decreased consciousness at presentation (Glasgow Coma Scale<15) (P < .002) were independent predictors of a discharge destination other than home. At the 3-month follow-up, the subgaleal group exhibited a mean improvement of 0.77 ± 1.2 points, while the subdural group had a deterioration of 0.14 ± 0.8 points (P < .01). Subgaleal drain location (P < .0001), better preoperative Glasgow Coma Scale (P = .01), and worse premorbid mRS (P = .0003) were independent predictors of improved mRS at 3 months. Recurrence requiring repeat surgery were more common in the subdural (13.6% (14/103) than the subgaleal 2.9% (1/34) group, P = .12), although the absolute incidence rates remained low. CONCLUSION: In patients undergoing minicraniotomy for cSDH, subgaleal drains are associated with shorter hospitalization, greater chance of discharge home, and better functional outcomes than subdural drains.

Glycosaminoglycan mimicry by COAM reduces melanoma growth through chemokine induction and function.

Chlorite-oxidized oxyamylose (COAM), a glycosaminoglycan mimetic and potent antiviral agent, provided significant growth reduction of syngeneic murine B16-F1 melanoma tumors. A single early dose (100 µg, into the site of tumor cell inoculation) was sufficient to establish a persistent effect over 17 days (resected tumor volume of 78.3 mm(3) in COAM-treated mice compared to 755.2 mm(3) in the control cohort, i.e., 89.6% reduction of tumor volumes). COAM was a much better antitumoral agent than the polyanionic glycosaminoglycan heparin. COAM retained its antitumoral effect in lymphopenic mice, reinforcing the idea of myeloid cell involvement. Massive recruitment of myeloid cells into dermal air pouches in response to COAM and their increased presence in early-treated tumors indicated that mainly CD11b(+) GR-1(+) myeloid cells were attracted by COAM to exert antitumoral effects. Leukocyte chemotaxis was mediated by the chemokine system through the induction in B16-F1 cells of mouse granulocyte chemotactic protein-2/CXCL6 upon COAM treatment. Thus, COAM constitutes a novel tool to study the role of innate immune cells in the initial stages of tumor development and an example that innate immunostimulating glycosaminoglycan mimicry may be exploited therapeutically.

Rescue from acute neuroinflammation by pharmacological chemokine-mediated deviation of leukocytes.

BACKGROUND: Neutrophil influx is an important sign of hyperacute neuroinflammation, whereas the entry of activated lymphocytes into the brain parenchyma is a hallmark of chronic inflammatory processes, as observed in multiple sclerosis (MS) and its animal models of experimental autoimmune encephalomyelitis (EAE). Clinically approved or experimental therapies for neuroinflammation act by blocking leukocyte penetration of the blood brain barrier. However, in view of unsatisfactory results and severe side effects, complementary therapies are needed. We have examined the effect of chlorite-oxidized oxyamylose (COAM), a potent antiviral polycarboxylic acid on EAE. METHODS: EAE was induced in SJL/J mice by immunization with spinal cord homogenate (SCH) or in IFN-γ-deficient BALB/c (KO) mice with myelin oligodendrocyte glycoprotein peptide (MOG35₋55). Mice were treated intraperitoneally (i.p.) with COAM or saline at different time points after immunization. Clinical disease and histopathology were compared between both groups. IFN expression was analyzed in COAM-treated MEF cell cultures and in sera and peritoneal fluids of COAM-treated animals by quantitative PCR, ELISA and a bioassay on L929 cells. Populations of immune cell subsets in the periphery and the central nervous system (CNS) were quantified at different stages of disease development by flow cytometry and differential cell count analysis. Expression levels of selected chemokine genes in the CNS were determined by quantitative PCR. RESULTS: We discovered that COAM (2 mg i.p. per mouse on days 0 and 7) protects significantly against hyperacute SCH-induced EAE in SJL/J mice and MOG35₋55-induced EAE in IFN-γ KO mice. COAM deviated leukocyte trafficking from the CNS into the periphery. In the CNS, COAM reduced four-fold the expression levels of the neutrophil CXC chemokines KC/CXCL1 and MIP-2/CXCL2. Whereas the effects of COAM on circulating blood and splenic leukocytes were limited, significant alterations were observed at the COAM injection site. CONCLUSIONS: These results demonstrate novel actions of COAM as an anti-inflammatory agent with beneficial effects on EAE through cell deviation. Sequestration of leukocytes in the non-CNS periphery or draining of leukocytes out of the CNS with the use of the chemokine system may thus complement existing treatment options for acute and chronic neuroinflammatory diseases.

Deficiency of gelatinase B/MMP-9 aggravates lpr-induced lymphoproliferation and lupus-like systemic autoimmune disease.

Gelatinase B/matrix metalloproteinase-9 (MMP-9) is a key enzyme involved in inflammatory, hematological, vascular and neoplastic diseases. In previous studies, we explored the intracellular substrate set or 'degradome' of MMP-9 and found many systemic autoantigens as novel intracellular gelatinase B substrates. Little is known, however, about the functional role of MMP-9 in the development of systemic autoimmunity in vivo. B6(lpr/lpr) mice with defective Fas-mediated apoptosis were used to investigate the functions of MMP-9 in lymphocyte proliferation and in the development of systemic autoimmunity. Combined Fas and gelatinase B deficiency resulted in extreme lymphoproliferative disease with enhanced lymphadenopathy and splenomegaly, and significantly reduced survival compared with single Fas deficiency. At the cellular level, this was corroborated by increased lymph node accumulation of 'double negative' T cells, B cells and myeloid cells. In addition, higher autoantibody titers and more pronounced autoimmune tissue injury were found in the absence of MMP-9, culminating in chronically enhanced systemic lupus erythematosus (SLE)-like autoimmunity. After cleavage by MMP-9 the SLE autoantigens U1snRNP A and ribosomal protein P0 were hardly recognized by plasma samples of both B6(lpr/lpr).MMP-9⁻/⁻ and B6(lpr/lpr).MMP-9+/+ mice, pointing to a destruction of B cell epitopes by MMP-9-mediated proteolysis. In addition, the same loss of immunodominant epitopes was observed with plasma samples from SLE patients, suggesting that MMP-9 suppresses systemic antibody-mediated autoimmunity by clearance of autoepitopes in immunogenic substrates. Thus, new protective functions for MMP-9 were revealed in the suppression of lymphoproliferation and dampening of systemic autoimmunity, cautioning against the long-term use of MMP inhibitors in autoimmune lymphoproliferative syndrome (ALPS) and SLE.

High-resolution characterization of gene function using single-cell CRISPR tiling screen.

Identification of novel functional domains and characterization of detailed regulatory mechanisms in cancer-driving genes is critical for advanced cancer therapy. To date, CRISPR gene editing has primarily been applied to defining the role of individual genes. Recently, high-density mutagenesis via CRISPR tiling of gene-coding exons has been demonstrated to identify functional regions in genes. Furthermore, breakthroughs in combining CRISPR library screens with single-cell droplet RNA sequencing (sc-RNAseq) platforms have revealed the capacity to monitor gene expression changes upon genetic perturbations at single-cell resolution. Here, we present "sc-Tiling," which integrates a CRISPR gene-tiling screen with single-cell transcriptomic and protein structural analyses. Distinct from other reported single-cell CRISPR screens focused on observing gene function and gene-to-gene/enhancer-to-gene regulation, sc-Tiling enables the capacity to identify regulatory mechanisms within a gene-coding region that dictate gene activity and therapeutic response.

Inflammatory rather than infectious insults play a role in exocrine tissue damage in a mouse model for coxsackievirus B4-induced pancreatitis.

Infection with coxsackievirus B4 (CVB4) may result in an acute severe necrotizing pancreatitis that mostly remains restricted to the acini of the exocrine parenchyma. The mechanisms responsible for this tissue damage, however, remain poorly understood. We here report that COAM, a polyanionic carboxylic acid, provides marked protection against CVB4-induced pancreatitis in a mouse model. Despite the fact that COAM largely reduced disease severity, as detected by serum amylase and lipase levels as well as histologically, titres of replicating CVB4 in the pancreas were virtually unaffected. COAM treatment diminished the infection-associated MMP-9 levels and also resulted in a decreased influx of neutrophils into the infected pancreas. Moreover, we demonstrate that titres of replicating virus in the pancreas did not directly correlate with the severity of disease. In conclusion, our data suggest that immunopathological effects, rather than direct virus-induced destruction, are responsible for the damage to acinar tissue in CVB4-induced pancreatitis.

Antiviral activity of chloroquine against human coronavirus OC43 infection in newborn mice.

Until recently, human coronaviruses (HCoVs), such as HCoV strain OC43 (HCoV-OC43), were mainly known to cause 15 to 30% of mild upper respiratory tract infections. In recent years, the identification of new HCoVs, including severe acute respiratory syndrome coronavirus, revealed that HCoVs can be highly pathogenic and can cause more severe upper and lower respiratory tract infections, including bronchiolitis and pneumonia. To date, no specific antiviral drugs to prevent or treat HCoV infections are available. We demonstrate that chloroquine, a widely used drug with well-known antimalarial effects, inhibits HCoV-OC43 replication in HRT-18 cells, with a 50% effective concentration (+/- standard deviation) of 0.306 +/- 0.0091 microM and a 50% cytotoxic concentration (+/- standard deviation) of 419 +/- 192.5 microM, resulting in a selectivity index of 1,369. Further, we investigated whether chloroquine could prevent HCoV-OC43-induced death in newborn mice. Our results show that a lethal HCoV-OC43 infection in newborn C57BL/6 mice can be treated with chloroquine acquired transplacentally or via maternal milk. The highest survival rate (98.6%) of the pups was found when mother mice were treated daily with a concentration of 15 mg of chloroquine per kg of body weight. Survival rates declined in a dose-dependent manner, with 88% survival when treated with 5 mg/kg chloroquine and 13% survival when treated with 1 mg/kg chloroquine. Our results show that chloroquine can be highly effective against HCoV-OC43 infection in newborn mice and may be considered as a future drug against HCoVs.

A pancoronavirus RT-PCR assay for detection of all known coronaviruses.

The recent discoveries of novel human coronaviruses, including the coronavirus causing SARS, and the previously unrecognized human coronaviruses HCoV-NL63 and HCoV-HKU1, indicate that the family Coronaviridae harbors more members than was previously assumed. All human coronaviruses characterized at present are associated with respiratory illnesses, ranging from mild common colds to more severe lower respiratory tract infections. Since the etiology of a relatively large percentage of respiratory tract diseases remains unidentified, it is possible that for a certain number of these illnesses, a yet unknown viral causative agent may be found. Screening for the presence of novel coronaviruses requires the use of a method that can detect all coronaviruses known at present. In this chapter, we describe a pancoronavirus degenerate primer-based method that allows the detection of all known and possibly unknown coronaviruses by RT-PCR amplification and sequencing of a 251-bp fragment of the coronavirus polymerase gene.

Evaluation of the efficacy of disinfectants against Puumala hantavirus by real-time RT-PCR.

Puumala virus, a hantavirus belonging to the Bunyaviridae family, causes a human disease known as nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome. The implementation of effective decontamination procedures is critical in hantavirus research to minimize the risk of personnel exposure. This study investigated the efficacy of Clidox((R)), Dettol((R)), ethanol, Halamid-d((R)), peracetic acid, sodium hypochloride and Virkon((R))S for inactivating Puumala virus. A real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to quantify Puumala virus before and after treatment with these products. Inactivation of Puumala virus was effective after 10min with all products except ethanol. Inactivation with absolute ethanol was effective only after 30min. Using the qRT-PCR method, this study has shown that the commercially available products Clidox((R)), Halamid-d((R)) and Virkon((R))S in particular represent a rapid and safe way to decontaminate surfaces with possible Puumala virus contamination. These products can be used in solutions of 1-2%, with contact times greater than 10min, for inactivating effectively Puumala virus.

A novel pancoronavirus RT-PCR assay: frequent detection of human coronavirus NL63 in children hospitalized with respiratory tract infections in Belgium.

BACKGROUND: Four human coronaviruses are currently known to infect the respiratory tract: human coronaviruses OC43 (HCoV-OC43) and 229E (HCoV-229E), SARS associated coronavirus (SARS-CoV) and the recently identified human coronavirus NL63 (HCoV-NL63). In this study we explored the incidence of HCoV-NL63 infection in children diagnosed with respiratory tract infections in Belgium. METHODS: Samples from children hospitalized with respiratory diseases during the winter seasons of 2003 and 2004 were evaluated for the presence of HCoV-NL63 using a optimized pancoronavirus RT-PCR assay. RESULTS: Seven HCoV-NL63 positive samples were identified, six were collected during January/February 2003 and one at the end of February 2004. CONCLUSIONS: Our results support the notation that HCoV-NL63 can cause serious respiratory symptoms in children. Sequence analysis of the S gene showed that our isolates could be classified into two subtypes corresponding to the two prototype HCoV-NL63 sequences isolated in The Netherlands in 1988 and 2003, indicating that these two subtypes may currently be cocirculating.

Enhanced immunostimulatory effects of DNA-encapsulated peptide hydrogels.

DNA that encodes tumor-specific antigens represents potential immunostimulatory agents. However, rapid enzymatic degradation and fragmentation of DNA during administration can result in limited vector expression and, consequently, poor efficacy. These challenges have necessitated the use of novel strategies for DNA delivery. Herein, we study the ability of cationic self-assembling peptide hydrogels to encapsulate plasmid DNA, and enhance its immunostimulatory potential in vivo. The effect of network charge on the gel's ability to retain the DNA was assessed employing three gel-forming peptides that vary systematically in formal charge. The peptide HLT2, having a formal charge of +5 at neutral pH, was optimal in encapsulating microgram quantities of DNA with little effect on its rheological properties, allowing its effective syringe delivery in vivo. The plasmid, DNA(TA), encapsulated within these gels encodes for a melanoma-specific gp100 antigen fused to the alarmin protein adjuvant HMGN1. Implantation of DNA(TA)-loaded HLT2 gels into mice resulted in an acute inflammatory response with the presence of polymorphonuclear cells, which was followed by infiltrating macrophages. These cellular infiltrates aid in the processing of encapsulated DNA, promoting increased lymphoproliferation and producing an enhanced immune response mediated by CD4+/IFNγ+ expressing Th1 cells, and complemented by the formation of gp100-specific antibodies.

Interference with glycosaminoglycan-chemokine interactions with a probe to alter leukocyte recruitment and inflammation in vivo.

In vivo leukocyte recruitment is not fully understood and may result from interactions of chemokines with glycosaminoglycans/GAGs. We previously showed that chlorite-oxidized oxyamylose/COAM binds the neutrophil chemokine GCP-2/CXCL6. Here, mouse chemokine binding by COAM was studied systematically and binding affinities of chemokines to COAM versus GAGs were compared. COAM and heparan sulphate bound the mouse CXC chemokines KC/CXCL1, MIP-2/CXCL2, IP-10/CXCL10 and I-TAC/CXCL11 and the CC chemokine RANTES/CCL5 with affinities in the nanomolar range, whereas no binding interactions were observed for mouse MCP-1/CCL2, MIP-1α/CCL3 and MIP-1ß/CCL4. The affinities of COAM-interacting chemokines were similar to or higher than those observed for heparan sulphate. Although COAM did not display chemotactic activity by itself, its co-administration with mouse GCP-2/CXCL6 and MIP-2/CXCL2 or its binding of endogenous chemokines resulted in fast and cooperative peritoneal neutrophil recruitment and in extravasation into the cremaster muscle in vivo. These local GAG mimetic features by COAM within tissues superseded systemic effects and were sufficient and applicable to reduce LPS-induced liver-specific neutrophil recruitment and activation. COAM mimics glycosaminoglycans and is a nontoxic probe for the study of leukocyte recruitment and inflammation in vivo.

The Alarmin HMGN1 contributes to antitumor immunity and is a potent immunoadjuvant.

Alarmins are endogenous mediators that are elicited rapidly in response to danger signals, enhancing innate and adaptive immune responses by promoting the recruitment and maturation of antigen-presenting cells (APC). The nucleosome-binding protein HMGN1 is a potent alarmin that binds TLR4 and induces antigen-specific Th1 immune responses, but its contributions to antitumor immunity have not been explored. We found that ovalbumin (OVA)-expressing EG7 mouse thymoma cells grew much faster in Hmgn1-deficient mice than littermate-matched controls. Tumor-bearing Hmgn1(-/-) mice generated fewer OVA-specific CD8 cells in the spleen than EG7-bearing Hmgn1(+/+) mice, suggesting that HMGN1 supported T cell-mediated antitumor immunity. In addition, EG7 tumors expressing HMGN1 grew more slowly than control EG7 tumors, suggesting greater resistance to HMGN1-expressing tumors. This resistance relied on T cell-mediated immunity because it was abolished by in vivo depletion of CD4(+) and CD8(+) T cells. Moreover, mice vaccinated with a DNA vector expressing an HMGN1-gp100 fusion protein manifested gp100-specific, Th1-polarized immune responses, acquiring resistance to challenge with mouse B16F1 melanoma. Overall, our findings show that HMGN1 contributes to antitumor immunity and it may offer an effective adjuvant to heighten responses to cancer vaccines.

Investigation of Fat Metabolism during Antiobesity Interventions by Magnetic Resonance Imaging and Spectroscopy.

The focus of current treatments for obesity is to reduce the body weight or visceral fat, which requires longer duration to show effect. In this study, we investigated the short-term changes in fat metabolism in liver, abdomen, and skeletal muscle during antiobesity interventions including Sibutra mine treatment and diet restriction in obese rats using magnetic resonance imaging, magnetic resonance spectroscopy, and blood chemistry. Sibutramine is an antiobesity drug that results in weight loss by increasing satiety and energy expenditure. The Sibutramine-treated rats showed reduction of liver fat and intramyocellular lipids on day 3. The triglycerides (TG) decreased on day 1 and 3 compared to baseline (day 0). The early response/nonresponse in different fat depots will permit optimization of treatment for better clinical outcome rather than staying with a drug for longer periods.

Insufficiently defined genetic background confounds phenotypes in transgenic studies as exemplified by malaria infection in Tlr9 knockout mice.

The use of genetically modified mice, i.e. transgenic as well as gene knockout (KO) and knock-in mice, has become an established tool to study gene function in many animal models for human diseases. However, a gene functions in a particular genomic context. This implies the importance of a well-defined homogenous genetic background for the analysis and interpretation of phenotypes associated with genetic mutations. By studying a Plasmodium chabaudi chabaudi AS (PcAS) malaria infection in mice bearing a TLR9 null mutation, we found an increased susceptibility to infection, i.e. higher parasitemia levels and increased mortality. However, this was not triggered by the deficient TLR9 gene itself. Instead, this disease phenotype was dependent on the heterogeneous genetic background of the mice, which appeared insufficiently defined as determined by single nucleotide polymorphism (SNP) analysis. Hence, it is of critical importance to study gene KO phenotypes on a homogenous genetic background identical to that of their wild type (WT) control counterparts. In particular, to avoid problems related to an insufficiently defined genetic background, we advocate that for each study involving genetically modified mice, at least a detailed description of the origin and genetic background of both the WT control and the altered strain of mice is essential.

Expression of angiostatic platelet factor-4var/CXCL4L1 counterbalances angiogenic impulses of vascular endothelial growth factor, interleukin-8/CXCL8, and stromal cell-derived factor 1/CXCL12 in esophageal and colorectal cancer.

Chemokines influence tumor progression through regulation of leukocyte chemotaxis, angiogenesis, and metastasis. In this study, the regulated expression of angiogenic (stromal cell-derived factor [SDF]-1/CXCL12 and interleukin [IL]-8/CXCL8) and angiostatic (platelet factor [PF]-4var/CXCL4L1 and inducible protein [IP-10]/CXCL10) chemokines was examined in human colorectal and esophageal cancer. In HCT 116 and HCT-8 colorectal adenocarcinoma cells, the production of IL-8 immunoreactivity was up-regulated by IL-1beta, tumor necrosis factor (TNF)-alpha, the toll-like receptor (TLR) ligands double-stranded RNA and peptidoglycan and phorbol ester. Increased PF-4 and synergistic IL-8 and IP-10 induction in carcinoma cells after stimulation with IL-1beta plus TNF-alpha or interferon-gamma was demonstrated by enzyme-linked immunosorbent assay, quantitative reverse transcriptase polymerase chain reaction, or immunocytochemistry. In addition, IL-8 from HT-29 colorectal adenocarcinoma cells was molecularly identified as intact chemokine, as well as NH(2)-terminally truncated, more active IL-8(6-77). The presence of PF-4var, SDF-1, and vascular endothelial growth factor (VEGF) was evidenced by immunohistochemistry in surgical samples from 51 patients operated on for colon adenocarcinoma (AC), esophageal AC, or esophageal squamous cell carcinoma (SCC). PF-4var was strongly detected in colorectal cancer, whereas its expression in esophageal cancer was rather weak. Staining for SDF-1 was almost negative in esophageal SCC, whereas a more intense and frequent staining was observed in AC of the esophagus and colon. Staining for VEGF was moderately to strongly positive in all 3 types of cancer, although less prominent in esophageal AC. The heterogenous expression of angiogenic (IL-8, SDF-1) as well as angiostatic (IP-10, PF-4var) chemokines not only within the tumor and between the different cases but also between the different tumor cell types may indicate a distinct role of the various chemokines in the complex process of tumor development.

Myeloid cells are tunable by a polyanionic polysaccharide derivative and co-determine host rescue from lethal virus infection.

Insight into molecular and cellular mechanisms of innate immunity is critical to understand viral pathogenesis and immunopathology and might be exploited for therapy. Whereas the molecular mechanisms of the IFN defense are well established, cellular mechanisms of antiviral immunity are only emerging, and their pharmacological triggering remains unknown. COAM is a polysaccharide derivative with antiviral activity but without comprehension about its mechanism of action. The COAM mixture was fractionated, and prophylactic treatment of mice with COAM polymers of high MW resulted in a conversion from 100% lethal mengovirus infection to an overall survival rate of 93% without obvious clinical sequelae. Differential and quantitative analysis of peritoneal leukocytes demonstrated that COAM induced a profound influx of neutrophils. Selective cell depletion experiments pointed toward neutrophils and macrophages as key effector cells in the rescue of mice from lethal mengovirus. COAM was able to induce mRNA and protein expression of the mouse neutrophil chemokine GCP-2. Binding of GCP-2 to COAM was demonstrated in solution and confirmed by SPR technology. Although COAM was not chemotactic for neutrophils, COAM-anchored muGCP-2 retained chemotactic activity for human and mouse neutrophils. In conclusion, this study established that COAM rescued mice from acute and lethal mengovirus infection by recruiting antiviral leukocytes to the site of infection, as proposed through the induction, binding, and concentration of endogenous chemokines. These findings reinforce the role of neutrophils and macrophages as critical cells that can be manipulated toward antiviral defense.

Replication reduction neutralization test, a quantitative RT-PCR-based technique for the detection of neutralizing hantavirus antibodies.

Hantaviruses, which are mainly rodent-borne viruses, cause hemorrhagic fever with renal syndrome in the Old World, and hantavirus pulmonary syndrome in the New World. A neutralization test based on quantitative RT-PCR, the replication reduction neutralization test (RRNT), was developed for efficient detection of hantavirus-neutralizing antibodies. The effectiveness of the RRNT was evaluated by examining several hantaviruses and hantavirus-specific convalescent human serum samples. All convalescent serum samples tested by RRNT caused significant decreases in hantavirus genomes with only one specific hantavirus species, which allowed a straightforward identification of the related hantavirus. The results obtained by RRNT were completely comparable with the results obtained by focus reduction neutralization test (FRNT). The RRNT approach is a reliable and rapid alternative for FRNT, hitherto considered as the gold standard for hantavirus serology.

Virus entry inhibition by chlorite-oxidized oxyamylose versus induction of antiviral interferon by poly(I:C).

Unlike polyribonucleotides, such as poly(I:C), chlorite-oxidized oxyamylose (COAM) has been poorly characterized as a polyanionic antiviral. COAM possesses a controversial interferon (IFN)-inducing capacity and its mechanism of action has not been elucidated. In this study, COAM was biochemically characterized and fractionated according to molecular mass. In comparison with a strong IFN induction and upregulation of the helicase RIG-I and MDA-5 mRNAs by poly(I:C), COAM did not enhance IFN-alpha or -beta and IFN-inducible RNA helicases in mouse fibroblastoid cells. Instead, COAM inhibited virus entry by blocking the attachment to the cells. These results suggest that COAM can alter the outcome of infection, not by IFN induction and in turn modifying the cellular antiviral state, but through inhibition of virus entry into cells.