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PubMed2005

A study of the metabolism of methamphetamine and 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in isolated rat hepatocytes.

The metabolism of methamphetamine (MA) and 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in freshly isolated rat hepatocytes was investigated, and compared with in vivo results. A suspended hepatocyte culture, established from male Wistar rats using a collagenase perfusion technique, was incubated in the presence of MA or 2C-B. After enzymatic hydrolysis of the conjugated forms, the metabolites were extracted by liquid-liquid partition and analyzed by gas chromatography/mass spectrometry (GC/MS). Amphetamine, p-hydroxymethamphetamine and p-hydroxyamphetamine were detected in the culture fluids of the rat hepatocytes inoculated with MA. The alcohol derivative, carboxylic acid derivative, 2-O-desmethyl-2C-B, 2-O-desmethyl-N-acetyl-2C-B and 5-O-desmethyl-N-acetyl-2C-B were detected in the case of 2C-B. The major metabolite of MA in rat hepatocytes was p-hydroxymethamphetamine. This is in good agreement with the urinary excretion profile for rats that were fed MA. 2-O-Desmethyl-2C-B and the carboxylic acid derivative were the major recovered metabolites of 2C-B in the rat hepatocyte culture, a slight deviation from the in vivo findings, in which 5-O-desmethyl-N-acetyl-2C-B was found to be the main component. Metabolites with a hydroxy group were largely present in their conjugated forms in the culture fluids, except for 2-O-desmethyl-2C-B. Taking these results into consideration, a primary hepatocyte culture system has the potential to provide a quick and handy method for estimating the in vivo metabolic fate of abused drugs.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed2005

Nonfatal and fatal DOB (2,5-dimethoxy-4-bromoamphetamine) overdose.

2,5-Dimethoxy-4-bromoamphetamine (DOB) is a strongly acting hallucinogen with an estimated effective dose of 2 mg for an 80 kg man. The case of two men who ingested a new "hallucinogen LSD-like" designer drug is reported here. They experienced intense hallucinations (onset after 15 min) and vomiting. The men became unconscious and fell into deep coma lasting several days. After an unknown period of time elapsed they were admitted to a hospital in a comatose state. One subject (AX, body mass 113 kg) survived, while the second subject (BX, body mass 65 kg) experienced convulsions, metabolic acidosis and died 6 days later. Gastric, blood, and urine specimens collected on admission into the hospital were sent for toxicological examination. Ethanol concentrations in the blood samples were less than 0.2 g/kg. CEDIA urine screening indicated the presence of THCOOH in both cases, while cocaine and its metabolites were only indicated in the urine from AX. Immunoassay for amphetamines was negative in urine specimens collected from both subjects. GC-MS analysis for unknown drugs allowed for the discovery of the presence of DOB in the gastric and urine samples of both persons. DOB-targeted analysis for the acetylated analyte confirmed its presence in both subjects. Quantitative analysis yielded concentrations in serum of 13 ng/ml (AX) and 19 ng/ml (BX). This report on both nonfatal and fatal DOB overdose cases is based on clear toxicological evidence, and is the first documentation of DOB consumption in the Czech Republic.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed2025

Pathogenicity assessment of genetic variants identified in patients with severe hypertriglyceridemia: Novel cases of familial chylomicronemia syndrome from the Dyslipidemia Registry of the Spanish Atherosclerosis Society.

PURPOSE: Genetic testing is required to confirm a diagnosis of familial chylomicronemia syndrome (FCS). We assessed the pathogenicity of variants identified in the FCS canonical genes to diagnose FCS cases. METHODS: 245 patients with severe hypertriglyceridemia underwent next-generation sequencing. Preliminary variant pathogenicity criteria and classification, based on the American College of Medical Genetics and Genomics guidelines, were obtained online and verified. Phenotype evaluation was based on lipoprotein lipase activity deficiency, a clinical score, and/or type I hyperlipoproteinemia determined in 25 patients. RESULTS: Twenty-four biallelic variants were analyzed. Evidence-based criteria allowed the reclassification of 8 likely pathogenic (LP) variants in the LPL, APOA5, and LMF1 genes into pathogenic (P) and the change of 2 variants of uncertain significance (VUS) to LP. Conversely, 2 variations in LMF1 remained as VUS. Additionally, 1 variant in LPL and 2 in GPIHBP1 were likely benign. Twenty FCS cases had biallelic P/LP variants and 1 patient, with an FCS phenotype, harbored biallelic VUS. FCS was excluded from 4 patients with pathogenic/likely benign combinations. CONCLUSION: The analysis of the clinical and biochemical features of patients with variants in the FCS canonical genes allowed a confident variant classification that helped in the diagnosis of novel FCS cases.

Humans↗

PubMed2005

Organ preservation in invasive bladder cancer: brachytherapy, an alternative to cystectomy and combined modality treatment?

PURPOSE: To evaluate our long-term results of bladder preservation with brachytherapy in the treatment of bladder cancer. METHODS AND MATERIALS: Between 1987 and 2000, 108 patients with T1-G3 and T2-T3a stages of bladder cancer were treated with a transurethral resection (TUR) and a course of external beam radiotherapy (30 Gy in 15 fractions) followed by brachytherapy (40 Gy). All tumors were solitary lesions with a diameter < or =5 cm. Median follow-up was 54 months (range, 1-178 months). RESULTS: The 5-year and 10-year overall survival rates were 62% and 50%, respectively. The 5-year and 10-year disease-specific survival rates were 73% and 67%, respectively. The actuarial local control rate was 73% at 5 and 73% at 10 years, respectively. The 5-year and 10-year disease-specific survival rates for patients with a preserved bladder were 68% and 59%, respectively. Of all long-term surviving patients, 90% preserved their native bladders. The treatment was well tolerated. Acute toxicity was mild. Two patients experienced serious late toxicity: 1 patient developed a persisting vesicocutaneous fistula and the other a stricture of the urethra and ureters. CONCLUSION: For patients with solitary, organ confined invasive bladder cancer < or =5 cm, bladder preservation with brachytherapy is an excellent alternative to radical cystectomy and combined modality treatment.

Analysis of Variance↗

PubMed2004

Preoperative intravenous midazolam: benefits beyond anxiolysis.

STUDY OBJECTIVE: To evaluate the effect of midazolam on the global perioperative experience, including patient satisfaction, postoperative nausea and vomiting, postoperative pain, and perioperative anxiety and amnesia. DESIGN: Prospective, randomized, placebo-controlled study. SETTING: Ambulatory surgical center affiliated with a tertiary-care hospital. PATIENTS: 88 ASA physical status I, II, and III patients scheduled for outpatient surgery. INTERVENTIONS: Patients were randomized into two groups to receive either 0.04 mg/kg of midazolam or placebo intravenously (IV) 20 minutes preoperatively. MEASUREMENTS: Perioperative measurements included blood pressure, heart rate, and oxygen saturation and the patient's level of anxiety; type of anesthetic administered; the anesthesiologist's guess at the treatment arm; perioperative dosages of fentanyl, morphine, and ondansetron; recovery room length of stay; frequency of nausea and vomiting, and level of postoperative pain in the 24 hours after surgery; the patient's overall satisfaction with the anesthetic, and whether the patient would recommend the premedication to a friend. MAIN RESULTS: Patient demographics, type of surgery/anesthesia, vital signs, case duration, recovery duration, and postoperative pain were all similar between the midazolam and placebo groups. As expected, IV midazolam was an effective anxiolytic. There was no evidence of retrograde amnesia. Fewer patients in the midazolam group suffered from postoperative nausea than did those in the placebo group (25%vs. 50%;p = 0.03), despite receiving similar perioperative antiemetic and opioid administration. Similarly, fewer patients in the midazolam group experienced postoperative vomiting than placebo group patients (8%vs. 21%), although this difference did not reach statistical significance. Only 42% of patients in the placebo group would recommend their premedication to a friend, compared with 85% of patients in the midazolam group (p < 0.001). CONCLUSIONS: In addition to the known anxiolytic effects of midazolam, midazolam premedication is an effective way to reduce the frequency of postoperative nausea, and perhaps vomiting, and increase patient satisfaction.

Adolescent↗

PubMed2004

The role of TGF-beta 1 and cytokines in the modulation of liver fibrosis by Sho-saiko-to in rat's bile duct ligated model.

Liver fibrosis is an over-accumulation of extra-cellular matrix (ECM) and the hepatic stellate cell (Ito cell) play a central role in the pathogenesis of liver fibrosis. There are a lot of growth factors and cytokines involved in the activation of hepatic stellate cell, including of transforming growth factor (TGF-alpha, TGF-beta1), platelet-derived growth factor (PDGF), interleukin (IL-1alpha,beta, IL-6) and tumor necrosis factor (TNF-alpha). Sho-saiko-to (TJ-9; Xiao-Chai-Hu-Tang in Chinese) was the most popular herbal medicine for the treatment of chronic liver disease in Chinese and Japanese. Our aim of the current study was to examine whether TJ-9 regulated the growth factors and cytokines in the fibrogenesis of bile duct ligated model. Therefore, we assessed the TJ-9's potential in regulating TGF-beta1, PDGF mRNA expression, the amount of IL-1alpha, IL-1beta, IL-6, TNF-alpha and the fibrotic marker "PIII NP" in the serum. Then, using the immunohistochemical stain to observe the TGF-beta1 expression in the tissue. Our results showed that TJ-9 at a dose of 0.5 g/(kgday) significantly reduced the serum level of PIII NP, the mRNA expression of TGF-beta1 and PDGF. For the cytokines involved in the activation of Ito cell, TJ-9 at a dose of 0.5 g/(kgday) significantly suppressed the increasing tendency of IL-1beta and enhanced the production of TNF-alpha. Finally, we concluded that: (1) TJ-9 at a dose of 0.5g/(kgday) significantly reduced the serum fibrotic marker PIII NP in the bile duct ligated model, and its mechanism was partly by means of downregulating the mRNA of TGF-beta1 and PDGF. These results also confirmed by the immunohistochemical staining of TGF-beta1. (2) TJ-9 at a dose of 0.5 g/(kgday) suppressed the increasing tendency of IL-1beta and stimulated the production of TNF-alpha to inhibit Ito cell proliferation and collagen formation.

Animals↗

PubMed2026

The musculoskeletal pain literacy questionnaire (MSK-PLq) - Part 1: Development of a preliminary version through a systematic review and Delphi consensus.

OBJECTIVE: Chronic musculoskeletal (MSK) pain is a leading cause of disability worldwide, and self-management is a first-line approach recommended by international clinical guidelines. Access to evidence-based information that enhances health literacy may support patients' engagement in their self-management and treatment decision-making, potentially reducing disease burden and pain. However, no tool currently exists to assess health literacy specifically in MSK pain. This study aimed to develop and describe the preliminary version of a knowledge-based questionnaire to evaluate MSK pain literacy, the Musculoskeletal Pain-Literacy questionnaire (MSK-PLq). METHODS: A systematic literature review identified existing health literacy instruments and generated a preliminary list of domains. A two-round Delphi study with 22 panellists (19 experts and three people living with chronic MSK pain), followed by consensus meetings, was used to refine domains and items (≥70% agreement). Readability was assessed using the Flesch Reading Ease (FRE) score and three stakeholders were consulted to review the questionnaire for comprehensibility, clarity, and face validity. RESULTS: Six domains were retained (Understand, Access, Appraise, Apply, Digital, Beliefs), comprising 20 items in the preliminary version of MSK-PLq. Readability was acceptable (mean FRE 74, indicating fairly easy reading), and subject feedback supported the questionnaire's clarity and face validity. CONCLUSIONS: The preliminary version of the MSK-PLq is proposed as the first knowledge-based tool to assess functional, interactive, and critical aspects of MSK pain literacy. It may have applications in clinical practice, research, education, and digital health, by informing tailored patient education and supporting self-management strategies, although further psychometric validation is required.

Humans↗

PubMed2026

Do adherence-focused interventions in low back pain have an impact on rehabilitation outcomes? A systematic review with meta-analysis.

BACKGROUND: Low back pain (LBP) is the leading cause of disability worldwide. Exercise-based interventions are effective, but adherence remains suboptimal. This systematic review and meta-analysis evaluated the effectiveness of strategies designed to enhance adherence to exercise-based interventions in individuals with LBP in terms of adherence as well as pain and functionality. METHODS: Randomized controlled trials including adults with non-specific LBP were eligible if they compared exercise-based interventions incorporating adherence-enhancing strategies versus exercise alone or usual care. Primary outcome was adherence; secondary outcomes were pain and functionality. Searches were conducted in PubMed, Embase, Web of Science, Cochrane Library, CINAHL, Scopus, and PEDro up to May 2026. Two reviewers independently screened studies, extracted data, and assessed risk of bias using the Cochrane RoB 2 tool. Random-effects meta-analyses were performed using standardized mean differences. Certainty of evidence was evaluated using the GRADE approach. RESULTS: Fourteen randomized controlled trials including 1233 participants were included. Risk of bias was low in six studies, with the remainder showing some concerns or high risk. For adherence outcomes, evidence showed no clear effect of adherence-enhancing strategies on either device-measured physical activity (SMD = 0.21, 95% CI -0.01 to 0.43; 3 trials, 320 participants; moderate-certainty evidence) or questionnaire-based adherence (SMD = 0.33, 95% CI -0.23 to 0.89; 4 trials, 377 participants; very low-certainty evidence). For pain and functionality, moderate certainty of evidence indicated small improvements favoring intervention groups in the medium term. CONCLUSIONS: Strategies to enhance adherence to exercise in LBP show uncertain effects on adherence but may provide small improvements in clinical outcomes in the medium term. Higher-quality trials are needed to strengthen the evidence base.

Adult↗

PubMed2005

Health related quality of life after mandibular resection for oral and oropharyngeal squamous cell carcinoma.

The impact of several clinical parameters on health related quality of life (HrQOL) was evaluated in patients with squamous cell carcinoma adjacent or fixed to the mandible with special emphasis on postoperative radiotherapy and type of mandibular resection. One-hundred and five returned EORTC-questionnaires were available for this study. Correlation analyses were used to determine the relationship between clinical parameters and HrQOL. Postoperative radiotherapy was the clinical parameter that affected HrQOL most. The type of mandibular resection had no influence on HrQOL. The affected QOL-items were all associated with eating problems, i.e. use of a feeding tube, use of nutritional supplements, swallowing, social eating, mouth opening and dry mouth. Postoperative radiotherapy should only be applied if strictly indicated. This implies that the application of postoperative radiotherapy may need reconsideration in cases without strict criteria for postoperative radiotherapy.

Adult↗

PubMed2026

Evolutionary and resistance dynamics in oligometastatic and oligoprogressive cancer treated with stereotactic radiotherapy and systemic therapies: A systematic review and focused meta-analysis.

BACKGROUND: Oligometastatic and oligoprogressive disease treated with stereotactic ablative radiotherapy (SABR) represents a clinically heterogeneous entity. Increasing evidence suggests that anatomical definitions alone may not adequately capture underlying biological diversity. This systematic review aimed to synthesize translational evidence exploring evolutionary dynamics, resistance mechanisms, and biomarker-driven stratification in patients treated with SABR. METHODS: A systematic literature review was performed including prospective and retrospective studies evaluating translational biomarkers in oligometastatic or oligoprogressive settings treated with SABR. Studies assessing genomic, transcriptomic, circulating or immune-related biomarkers were included. Data were summarized qualitatively according to predefined translational domains: (i) evolutionary dynamics under systemic therapy pressure, (ii) baseline biological stratification, (iii) longitudinal circulating biomarkers, and (iv) systemic immune remodeling. Exploratory quantitative visual syntheses were performed using reported hazard ratios when conceptually comparable endpoints were available. RESULTS: 19 studies comprising 1527 patients were included. Across tumor types and treatment contexts, translational analyses consistently indicated that anatomically defined oligometastatic states encompass biologically distinct subgroups with different risks of systemic progression. Studies evaluating oligoprogression under ongoing systemic therapy suggested a distinction between spatially constrained resistance and systemic molecular escape, supported by circulating tumor DNA and tissue- or plasma-based molecular profiling (including genomic and transcriptomic analyses). Baseline biological features, including adverse genomic signatures and circulating biomarkers, were associated with inferior progression outcomes despite metastasis-directed therapy. Longitudinal biomarkers provided early signals of treatment response and systemic control. Immune remodeling after SABR showed context-dependent effects, both systemic immune activation and treatment-related immunosuppression reported across studies.

Humans↗

PubMed2005

Metabolic pathways of 4-bromo-2,5-dimethoxyphenethylamine (2C-B): analysis of phase I metabolism with hepatocytes of six species including human.

4-Bromo-2,5-dimethoxyphenethylamine (2C-B) is a psychoactive designer drug of abuse that is sold under the street names "Venus", "Bromo", "Erox", "XTC" or "Nexus". Concern has been raised because only little is known about its toxicity and metabolism in humans. In the present study we incubated 2C-B with human, monkey, dog, rabbit, rat and mouse hepatocytes to identify the metabolites formed and to determine possible toxic effects as evidenced by an ATP assay. Our data allow construction of the main metabolic pathways of 2C-B. Oxidative deamination results in the 2-(4-bromo-2,5-dimethoxyphenyl)-ethanol (BDMPE) and 4-bromo-2,5-dimethoxyphenylacetic acid (BDMPAA) metabolites. Additionally, 4-bromo-2,5-dimethoxybenzoic acid (BDMBA) can be produced also by oxidative deamination. Further metabolism of BDMPE and BDMPAA may occur by demethylation. Alternatively, the later metabolites can be generated by demethylation of 2C-B followed by oxidative deamination. Two remarkable interspecies differences in metabolism of 2C-B were observed (i) a hitherto unknown metabolite, 4-bromo-2,5-dimethoxy-phenol (BDMP), was identified after incubation only with mouse hepatocytes; (ii) 2-(4-bromo-2-hydroxy-5-methoxyphenyl)-ethanol (B-2-HMPE) was produced by hepatocytes from human, monkey and rabbit but not by dog, rat and mouse. Comparing the toxic effects of 2C-B between hepatocytes of the six examined species we observed only minor interspecies differences. However, large inter-individual differences in susceptibility of hepatocytes from three human donors were observed.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗

PubMed2004

Determinants within gp120 and gp41 contribute to CD4 independence of SIV Envs.

Entry of simian immunodeficiency virus (SIV) into cells is mediated by binding of the viral envelope (Env) glycoprotein to cellular CD4 and chemokine receptor molecules. Interaction of the Env gp120 subunit with CD4 induces conformational changes that result in exposure of a conserved coreceptor binding site. The chemokine receptor CCR5 is the major coreceptor used for SIV entry. Many SIV Envs have the ability to bind directly to CCR5 in the absence of CD4, and CD4-independent SIVs have been shown to exhibit macrophage tropism, enhanced neutralization sensitivity, and reduced pathogenicity in nonhuman primates. SIVmac239 is a pathogenic, T-tropic, neutralization-resistant virus which encodes a CD4-dependent Env. By contrast, the SIVmac316 virus, which differs from 239 in Env by only eight amino acid substitutions and a gp41 cytoplasmic domain truncation, exhibits macrophage tropism in vitro, attenuated pathogenesis, neutralization sensitivity, and CD4-independent entry. We mapped the residues contributing to CD4-independent entry to substitutions at position 165 in the V1/V2 region of gp120 and position 573 of gp41. We find that substitution of both residues in replication-competent SIVmac239 virus results in gain of CD4 independence and enhanced neutralization sensitivity. By contrast, the converse substitutions placed in the background of SIVmac316 resulted in loss of CD4 independence and decreased neutralization sensitivity. Thus, as few as two amino acid changes can have dramatic effects on SIV Env phenotype.

Amino Acid Substitution↗

PubMed2005

An infectious West Nile virus that expresses a GFP reporter gene.

West Nile virus is a mosquito-borne, neurotropic flavivirus that causes encephalitis in humans and animals. Since being introduced into the Western hemisphere in 1999, WNV has spread rapidly across North America, identifying this virus as an important emerging pathogen. In this study, we developed a DNA-launched infectious molecular clone of WNV that encodes a GFP reporter gene. Transfection of cells with the plasmid encoding this recombinant virus (pWNII-GFP) resulted in the production of infectious WNV capable of expressing GFP at high levels shortly after infection of a variety of cell types, including primary neurons and dendritic cells. Infection of cells with WNII-GFP virus was productive, and could be inhibited with both monoclonal antibodies and interferon-beta, highlighting the potential of this system in the development and characterization of novel inhibitors and therapeutics for WNV infection. As expected, insertion of the reporter gene into the viral genome was associated with a reduced rate of viral replication, providing the selective pressure for the development of variants that no longer encoded the full-length reporter gene cassette. We anticipate this DNA-based, infectious WNV reporter virus will allow novel approaches for the study of WNV infection and its inhibition both in vitro and in vivo.

Animals↗

PubMed2005

Characterization of neutralizing antibodies to West Nile virus.

We produced nine monoclonal antibodies (MAbs) directed against the West Nile virus E glycoprotein using three different immunization strategies: inactivated virus, naked DNA, and recombinant protein. Most of the MAbs bound to conformation dependent epitopes in domain III of the E protein. Four of the MAbs neutralized WNV infection and bound to the same region of domain III with high affinity. The neutralizing MAbs were obtained from mice immunized with inactivated virus alone or in combination with a DNA plasmid. In contrast, MAbs obtained by immunization with a soluble version of the E glycoprotein did not exhibit neutralizing activity. These non-neutralizing antibodies were cross-reactive with several other flaviviruses, including Saint Louis encephalitis, Japanese encephalitis, Yellow Fever and Powassan viruses. Interestingly, some non-neutralizing MAbs bound with high affinity to domains I or III, indicating that both affinity and the precise epitope recognized by an antibody are important determinants of WNV neutralization.

Animals↗

PubMed2005

A rapid and quantitative assay for measuring antibody-mediated neutralization of West Nile virus infection.

West Nile virus (WNV) is a neurotropic flavivirus within the Japanese encephalitis antigenic complex that is responsible for causing West Nile encephalitis in humans. The surface of WNV virions is covered by a highly ordered icosahedral array of envelope proteins that is responsible for mediating attachment and fusion with target cells. These envelope proteins are also primary targets for the generation of neutralizing antibodies in vivo. In this study, we describe a novel approach for measuring antibody-mediated neutralization of WNV infection using virus-like particles that measure infection as a function of reporter gene expression. These reporter virus particles (RVPs) are produced by complementation of a sub-genomic replicon with WNV structural proteins provided in trans using conventional DNA expression vectors. The precision and accuracy of this approach stem from an ability to measure the outcome of the interaction between antibody and viral antigens under conditions that satisfy the assumptions of the law of mass action as applied to virus neutralization. In addition to its quantitative strengths, this approach allows the production of WNV RVPs bearing the prM-E proteins of different WNV strains and mutants, offering considerable flexibility for the study of the humoral immune response to WNV in vitro. WNV RVPs are capable of only a single round of infection, can be used under BSL-2 conditions, and offer a rapid and quantitative approach for detecting virus entry and its inhibition by neutralizing antibody.

Animals↗

PubMed2006

Functional impact of HIV coreceptor-binding site mutations.

The bridging sheet region of the gp120 subunit of the HIV-1 Env protein interacts with the major virus coreceptors, CCR5 and CXCR4. We examined the impact of mutations in and adjacent to the bridging sheet region of an X4 tropic HIV-1 on membrane fusion and entry inhibitor susceptibility. When the V3-loop of this Env was changed so that CCR5 was used, the effects of these same mutations on CCR5 use were assayed as well. We found that coreceptor-binding site mutations had greater effects on CXCR4-mediated fusion and infection than when CCR5 was used as a coreceptor, perhaps related to differences in coreceptor affinity. The mutations also reduced use of the alternative coreceptors CCR3 and CCR8 to varying degrees, indicating that the bridging sheet region is important for the efficient utilization of both major and minor HIV coreceptors. As seen before with a primary R5 virus strain, bridging sheet mutations increased susceptibility to the CCR5 inhibitor TAK-779, which correlated with CCR5 binding efficiency. Bridging sheet mutations also conferred increased susceptibility to the CXCR4 ligand AMD-3100 in the context of the X4 tropic Env. However, these mutations had little effect on the rate of membrane fusion and little effect on susceptibility to enfuvirtide, a membrane fusion inhibitor whose activity is dependent in part on the rate of Env-mediated membrane fusion. Thus, mutations that reduce coreceptor binding and enhance susceptibility to coreceptor inhibitors can affect fusion and enfuvirtide susceptibility in an Env context-dependent manner.

Binding Sites↗

PubMed2006

Development and characterization of a Rift Valley fever virus cell-cell fusion assay using alphavirus replicon vectors.

Rift Valley fever virus (RVFV), a member of the Phlebovirus genus in the Bunyaviridae family, is transmitted by mosquitoes and infects both humans and domestic animals, particularly cattle and sheep. Since primary RVFV strains must be handled in BSL-3+ or BSL-4 facilities, a RVFV cell-cell fusion assay will facilitate the investigation of RVFV glycoprotein function under BSL-2 conditions. As for other members of the Bunyaviridae family, RVFV glycoproteins are targeted to the Golgi, where the virus buds, and are not efficiently delivered to the cell surface. However, overexpression of RVFV glycoproteins using an alphavirus replicon vector resulted in the expression of the glycoproteins on the surface of multiple cell types. Brief treatment of RVFV glycoprotein expressing cells with mildly acidic media (pH 6.2 and below) resulted in rapid and efficient syncytia formation, which we quantified by beta-galactosidase alpha-complementation. Fusion was observed with several cell types, suggesting that the receptor(s) for RVFV is widely expressed or that this acid-dependent virus does not require a specific receptor to mediate cell-cell fusion. Fusion occurred over a broad temperature range, as expected for a virus with both mosquito and mammalian hosts. In contrast to cell fusion mediated by the VSV-G glycoprotein, RVFV glycoprotein-dependent cell fusion could be prevented by treating target cells with trypsin, indicating that one or more proteins (or protein-associated carbohydrate) on the host cell surface are needed to support membrane fusion. The cell-cell fusion assay reported here will make it possible to study the membrane fusion activity of RVFV glycoproteins in a high-throughput format and to screen small molecule inhibitors for the ability to block virus-specific membrane fusion.

Alphavirus↗

PubMed2006

The neutralizing antibody response against West Nile virus in naturally infected horses.

A major neutralizing epitope (here referred to as the T332 epitope) located on the lateral surface of domain III (DIII) of the West Nile virus (WNV) envelope protein has been identified based on the analysis of murine monoclonal antibodies. However, little is known about the humoral immune response against WNV in a natural host or whether DIII in general or the T332 epitope in particular are important targets of neutralizing antibodies in vivo. To characterize the types of antibodies produced during infection with WNV, we studied a group of naturally infected horses. Using immune adsorption assays coupled with the use of virus particles bearing mutations in the T332 epitope, we found that in some animals neutralizing activity against DIII and the T332 epitope was below the limit of detection. In contrast, some animals generated a significant fraction of neutralizing activity to DIII and the T332 epitope. Thus, while antibodies to the T332 epitope did not represent a significant fraction of the total antibody response in the infected animals studied, in some horses, they comprised a significant fraction of neutralizing activity, making this an important but far from dominant neutralizing epitope. Rather, the neutralizing response to WNV generated in infected horses is both variable and polyclonal in nature, with epitopes within and outside of DIII playing important roles.

Animals↗