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1.
Radiol Case Rep ; 18(3): 1005-1009, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36684621

ABSTRACT

Adverse reaction to metal debris (ARMD) is a known complication of metal-on-metal hip arthroplasty. There has been one previously reported case of ARMD with concomitant gout in the setting of a hip arthroplasty. We report a case of ARMD with accompanying monosodium urate crystals as well as amyloid deposition in the hip of a patient who had undergone a metal-on-metal hip arthroplasty. This is the only published case to date of these 3 conditions co-existing, although it is possible that the incidence is higher since these require special diagnostic tests that are not routinely performed. It is postulated that these entities are biochemically associated with each other rather than being purely coincidental.

2.
Cancer Lett ; 546: 215831, 2022 10 10.
Article in English | MEDLINE | ID: mdl-35868533

ABSTRACT

Low-dose carbon monoxide (CO) is under investigation in clinical trials to treat non-cancerous diseases and has an excellent safety profile. Due to early detection and cancer awareness, an increasing number of cancer patients are diagnosed at early stages, when potentially curative surgical resection can be done. However, many patients ultimately experience recurrence. Here, we evaluate the therapeutic effect of CO on metastatic cancer progression. We show that 250 ppm CO inhibits the migration of multiple types of cancer cell lines, including breast, pancreatic, colon, prostate, liver, and lung cancer and reduces the ability to adhere to fibronectin. We demonstrate that in mouse models, 250 ppm inhaled CO inhibits lung metastasis of breast cancer and liver metastasis of pancreatic cancer. Moreover, low-dose CO suppresses recurrence and increases survival after surgical removal of primary pancreatic cancer in mice. Mechanistically, low-dose CO blocks transcription of heme importers, leading to diminished intracellular heme levels and a heme-regulated enzyme, cytochrome P4501B1 (CYP1B1). Either supplementing heme or overexpressing CYP1B1 reverses the anti-migration effect of low-dose CO. Taken together, low-dose CO therapy inhibits cell migration, reduces adhesion to fibronectin, prevents disseminated cancer cells from expanding into gross metastases, and improves survival in pre-clinical mouse models of metastasis.


Subject(s)
Lung Neoplasms , Pancreatic Neoplasms , Animals , Carbon Monoxide , Fibronectins , Heme , Heme Oxygenase-1 , Male , Mice
3.
Radiol Case Rep ; 17(1): 194-200, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34815826

ABSTRACT

Sweet syndrome is an uncommon inflammatory skin condition. Here we present a case of Sweet syndrome in a young woman with rare extracutaneous manifestations, including bone and splenic fluid collections, with marked improvement following treatment with systemic corticosteroids. The patient was subsequently diagnosed with Crohn's disease which can be seen in the setting of Sweet syndrome. Sterile abscesses should be considered in patients with a clinical diagnosis of Sweet syndrome and focal symptomatology.

4.
Radiol Case Rep ; 16(7): 1718-1726, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34007391

ABSTRACT

Differentiation of primary versus secondary breast cancer can be difficult, with the relative rarity of the latter representing a diagnostic challenge. Here, we present a case of small cell lung cancer with synchronous bilateral breast metastases in a 52-year-old female. There are less than 5 other cases of small cell lung cancer with bilateral breast metastases reported in the literature to date. The breast metastases represented the first clinical and imaging manifestation of malignancy in our case. We present the patient's disease course including multi-modal imaging, histopathologic analysis, and clinical management. We aim to highlight the entity of secondary breast cancer and how multidisciplinary collaboration can help arrive at the diagnosis, which is critical for prognosis and treatment planning in this patient population.

5.
Radiol Case Rep ; 15(11): 2308-2313, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32983305

ABSTRACT

Fat emboli are a common phenomenon, but are rarely detected or reported on extremity CT imaging. We present a case of fat embolus in the popliteal vein in the setting of a femoral fracture. This is the most distal fat embolus described in the literature. There are no guidelines regarding intervention if a fat embolus is detected in a peripheral vein on CT. A review of all the previous cases of peripheral fat emboli is presented for reference.

6.
Virology ; 493: 173-88, 2016 06.
Article in English | MEDLINE | ID: mdl-27058764

ABSTRACT

Mumps virus (MuV) is postulated to adhere to the "rule of six" for efficient replication. To examine the requirement for MuV, minigenomes of nonpolyhexameric length (6n-1 and 6n+1) were analyzed. Expression of the reporter gene CAT was significantly reduced with minigenomes of nonpolyhexameric length compared to the wild type 6n genome, and reduction was more pronounced for the 6n-1 than for the 6n+1 minigenome. That 6n-1 genomes are impacted by nonconformance with the rule of six to a greater degree as compared to 6n+1 genomes was also suggested with MuV derived from cDNA coding for 6n+1 or 6n-1 genomes. While viruses recovered from 6n+1 cDNAs maintained a nonpolyhexameric genome length over multiple replication cycles, viruses rescued from the 6n-1 cDNAs acquired length correcting mutations rapidly following rescue. Our data indicate that polyhexameric genomes are the preferred template for the MuV RNA polymerase, but that this requirement is not absolute.


Subject(s)
Genome, Viral , Mumps virus/physiology , Virus Replication/genetics , Animals , Cell Line , Chlorocebus aethiops , DNA, Complementary , DNA, Viral , DNA-Directed RNA Polymerases/metabolism , Genome Size , Mumps virus/genetics , Vero Cells , Viral Proteins/metabolism
7.
J Diabetes Complications ; 30(4): 628-37, 2016.
Article in English | MEDLINE | ID: mdl-26935335

ABSTRACT

OBJECTIVE: The objective of this study is to examine the effect of acarbose, an alpha-glucosidase inhibitor, on body weight in a real-life setting by pooling data from post-marketing surveillance. METHODS: Data from 10 studies were pooled (n=67,682) and the effect of acarbose on body weight was analysed taking into account baseline body weight, glycemic parameters and other baseline characteristics. RESULTS: The mean relative reduction in body weight was 1.45 ± 3.24% at the 3-month visit (n=43,510; mean baseline 73.4 kg) and 1.40 ± 3.28% at the last visit (n=54,760; mean baseline 73.6 kg) (both p<0.0001). These reductions were dependent on baseline body weight (overweight: -1.33 ± 2.98% [n=13,498; mean baseline 71.6 kg]; obese: -1.98 ± 3.40% [n=20,216; mean baseline 81.3 kg]). When analysed by baseline glycemic parameter quartiles, the reduction was independent of fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycated hemoglobin (HbA1c) and postprandial glucose excursion (PPGE). A bivariate analysis of covariance identified female sex, South East Asian and East Asian ethnicity, younger age, higher body mass index, short duration of diabetes, and no previous treatment as factors likely to impact positively on body weight reduction with acarbose. CONCLUSIONS: This post-hoc analysis showed that acarbose treatment reduces body weight independent of glycemic control status but dependent on baseline body weight.


Subject(s)
Acarbose/therapeutic use , Anti-Obesity Agents/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Global Health , Glycoside Hydrolase Inhibitors/therapeutic use , Obesity/drug therapy , Overweight/drug therapy , Acarbose/adverse effects , Age Factors , Anti-Obesity Agents/adverse effects , Asian People , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/complications , Female , Global Health/ethnology , Glycoside Hydrolase Inhibitors/adverse effects , Humans , Hyperglycemia/prevention & control , Hypoglycemia/chemically induced , Hypoglycemia/prevention & control , Male , Middle Aged , Obesity/complications , Obesity/ethnology , Observational Studies as Topic , Overweight/complications , Overweight/ethnology , Product Surveillance, Postmarketing , Sex Characteristics , Weight Loss/drug effects
8.
Virus Genes ; 51(1): 12-24, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25962759

ABSTRACT

As a member of the family paramyxoviridae, subfamily paramyxovirinae, the genome of mumps virus (MuV) is postulated to be polyhexameric in length in order to be able to replicate efficiently. While all natural MuV strains sequenced so far obey to this "rule of six," we describe here the isolation of recombinant MuVs that appeared to contain an additional U residue in the homopolymeric tract of the F gene-end signal, resulting in a genome length of 6n + 1. Sequencing of several plaque-purified viruses from these preparations did not reveal the existence of length-correcting mutations, suggesting that they are violators of the rule of six. Employing high-throughput sequencing technology, we provide evidence that the insertion of an additional U residue is mainly the result of the rescue system used that relies on T7 RNA polymerase. Limited in vitro and in vivo testing of the viruses did not reveal any significant impact of the longer genome on virus replication or virulence, suggesting that the rule of six is not a strict requirement for MuV replication.


Subject(s)
Mumps virus/physiology , Mutagenesis, Insertional , Mutant Proteins/metabolism , Viral Fusion Proteins/metabolism , Virus Replication , Animals , Chlorocebus aethiops , Mumps virus/genetics , Mumps virus/isolation & purification , Mutant Proteins/genetics , RNA, Viral/genetics , Sequence Analysis, DNA , Vero Cells , Viral Fusion Proteins/genetics , Viral Plaque Assay , Virulence
9.
Open Forum Infect Dis ; 1(3): ofu094, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25734162

ABSTRACT

BACKGROUND: Mumps outbreaks in populations with high 2-dose measles-mumps-rubella (MMR) vaccine coverage raise the question whether a third dose of MMR vaccine (MMR3) is needed. However, data on the immunogenicity of MMR3 are limited. We assessed mumps virus neutralizing antibody levels pre- and post-MMR3 in a nonoutbreak setting. METHODS: Mumps antibody titers were assessed at baseline, 1 month, and 1 year after MMR3 in subjects aged 18-28 years. RESULTS: At baseline, 5 of 656 (0.8%) subjects had seronegative mumps neutralizing antibody titers and 38 (5.8%) had low titers. One year post-MMR3, these numbers declined to 3 (0.5%) and 16 (2.4%), respectively. Subjects with low baseline titers were more likely to have low 1-month and 1-year titers (R (2) = 0.81-0.87, P < .0001). Compared to baseline, geometric mean titers were significantly higher at 1 month (P < .0001) and 1 year (P < .01) post-MMR3; however, reverse cumulative distribution curves showed only minimal shifts in mumps titers from baseline to 1 month and 1 year. CONCLUSIONS: Very few subjects had negative or low baseline mumps titers. Nonetheless, mumps titers had modest but significant increases when measured 1 month and 1 year post-MMR3. This temporary increase in titers could decrease susceptibility to disease during outbreaks, but may have limited value for routine use in vaccinated populations.

10.
J Foot Ankle Res ; 5: 20, 2012 Aug 13.
Article in English | MEDLINE | ID: mdl-22889267

ABSTRACT

BACKGROUND: Foot orthoses are often used to treat lower limb injuries associated with excessive pronation. There are many orthotic modifications available for this purpose, with one being the medial heel skive. However, empirical evidence for the mechanical effects of the medial heel skive modification is limited. This study aimed to evaluate the effect that different depths of medial heel skive have on plantar pressures. METHODS: Thirty healthy adults (mean age 24 years, range 18-46) with a flat-arched or pronated foot posture and no current foot pain or deformity participated in this study. Using the in-shoe pedar-X® system, plantar pressure data were collected for the rearfoot, midfoot and forefoot while participants walked along an 8 metre walkway wearing a standardised shoe. Experimental conditions included a customised foot orthosis with the following 4 orthotic modifications: (i) no medial heel skive, (ii) a 2 mm medial heel skive, (iii) a 4 mm medial heel skive and (iv) a 6 mm medial heel skive. RESULTS: Compared to the foot orthosis with no medial heel skive, statistically significant increases in peak pressure were observed at the medial rearfoot - there was a 15% increase (p = 0.001) with the 4 mm skive and a 29% increase (p < 0.001) with the 6 mm skive. No significant change was observed with the 2 mm medial heel skive. With respect to the midfoot and forefoot, there were no significant differences between the orthoses. CONCLUSIONS: This study found that a medial heel skive of 4 mm or 6 mm increases peak pressure under the medial rearfoot in asymptomatic adults with a flat-arched or pronated foot posture. Plantar pressures at the midfoot and forefoot were not altered by a medial heel skive of 2, 4 or 6 mm. These findings provide some evidence for the effects of the medial heel skive orthotic modification.

11.
J Virol ; 86(1): 615-20, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22072778

ABSTRACT

Recently, numerous large-scale mumps outbreaks have occurred in vaccinated populations. Clinical isolates sequenced from these outbreaks have invariably been of genotypes distinct from those of vaccine viruses, raising concern that certain mumps virus strains may escape vaccine-induced immunity. To investigate this concern, sera obtained from children 6 weeks after receipt of measles, mumps, and rubella (MMR) vaccine were tested for the ability to neutralize a carefully selected group of genetically diverse mumps virus strains. Although the geometric mean neutralizing antibody titer of the sera was lower against some virus strains than others, all viruses were readily neutralized, arguing against immune escape.


Subject(s)
Disease Outbreaks , Measles-Mumps-Rubella Vaccine/immunology , Mumps virus/immunology , Mumps/epidemiology , Mumps/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Child , Child, Preschool , Female , Humans , Male , Measles-Mumps-Rubella Vaccine/administration & dosage , Molecular Sequence Data , Mumps/virology , Mumps virus/classification , Mumps virus/genetics , Phylogeny , United States/epidemiology , Vaccination
12.
J Infect Dis ; 204(9): 1413-22, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21933874

ABSTRACT

BACKGROUND: In 2006, a mumps outbreak occurred on a university campus despite ≥ 95% coverage of students with 2 doses of measles-mumps-rubella (MMR) vaccine. Using plasma samples from a blood drive held on campus before identification of mumps cases, we compared vaccine-induced preoutbreak mumps antibody levels between individuals who developed mumps (case patients) and those who did not develop mumps (nonpatients). METHODS: Preoutbreak samples were available from 11 case patients, 22 nonpatients who reported mumps exposure but no mumps symptoms, and 103 nonpatients who reported no known exposure and no symptoms. Antibody titers were measured by plaque reduction neutralization assay using Jeryl Lynn vaccine virus and the outbreak virus Iowa-G/USA-06 and by enzyme immunoassay (EIA). RESULTS: Preoutbreak Jeryl Lynn virus neutralization titers were significantly lower among case patients than unexposed nonpatients (P = .023), and EIA results were significantly lower among case patients than exposed nonpatients (P = .007) and unexposed nonpatients (P = .009). Proportionately more case patients than exposed nonpatients had a preoutbreak anti-Jeryl Lynn titer < 31 (64% vs 27%, respectively; P = .065), an anti-Iowa-G/USA-06 titer < 8 (55% vs 14%; P = .033), and EIA index standard ratio < 1.40 (64% vs 9%; P = .002) and < 1.71 (73% vs 14%, P = .001). DISCUSSION: Case patients generally had lower preoutbreak mumps antibody levels than nonpatients. However, titers overlapped and no cutoff points separated all mumps case patients from all nonpatients.


Subject(s)
Antibodies, Viral/blood , Disease Outbreaks , Mumps/epidemiology , Mumps/prevention & control , Adolescent , Antibodies, Neutralizing/blood , Biomarkers , Female , Humans , Immunoenzyme Techniques , Iowa/epidemiology , Male , Measles-Mumps-Rubella Vaccine/administration & dosage , Measles-Mumps-Rubella Vaccine/immunology , Mumps/immunology , Students , Viral Plaque Assay , Young Adult
13.
J Virol ; 85(14): 7059-69, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21543475

ABSTRACT

Mumps virus (MuV) is highly neurotropic and was the leading cause of aseptic meningitis in the Western Hemisphere prior to widespread use of live attenuated MuV vaccines. Due to the absence of markers of virus neuroattenuation and neurovirulence, ensuring mumps vaccine safety has proven problematic, as demonstrated by the occurrence of aseptic meningitis in recipients of certain vaccine strains. Here we examined the genetic basis of MuV neuroattenuation and neurovirulence by generating a series of recombinant viruses consisting of combinations of genes derived from a cDNA clone of the neurovirulent wild-type 88-1961 strain (r88) and from a cDNA clone of the highly attenuated Jeryl Lynn vaccine strain (rJL). Testing of these viruses in rats demonstrated the ability of several individual rJL genes and gene combinations to significantly neuroattenuate r88, with the greatest effect imparted by the rJL nucleoprotein/matrix protein combination. Interestingly, no tested combination of r88 genes, including the nucleoprotein/matrix protein combination, was able to convert rJL into a highly neurovirulent virus, highlighting mechanistic differences between processes involved in neuroattenuation and neurovirulence.


Subject(s)
Attention , Central Nervous System/virology , Genes, Viral , Mumps virus/pathogenicity , Animals , Chlorocebus aethiops , Mumps virus/genetics , Mumps virus/physiology , Rats , Rats, Inbred Lew , Reverse Transcriptase Polymerase Chain Reaction , Vero Cells , Virulence , Virus Replication
14.
J Virol ; 85(12): 6082-5, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21471236

ABSTRACT

Deletion of the small hydrophobic (SH) protein of certain paramyxoviruses has been found to result in attenuation, suggesting that the SH protein is a virulence factor. To investigate the role of the mumps virus (MuV) SH protein in virulence, multiple stop codons were introduced into the open reading frame (ORF) of a MuV molecular clone (r88-1961(SHstop)), preserving genome structure but precluding production of the SH protein. No differences in neurovirulence were seen between the wild-type and the SH(stop) viruses. In contrast, upon deletion of the SH gene, significant neuroattenuation was observed. These data indicate that the MuV SH protein is not a neurovirulence factor and highlight the importance of distinguishing gene deletion effects from protein-specific effects.


Subject(s)
Gene Deletion , Mumps virus/pathogenicity , Protein Biosynthesis , Viral Proteins/genetics , Animals , Brain/virology , Chlorocebus aethiops , Codon, Terminator , Humans , Hydrocephalus/virology , Mumps virus/genetics , Mumps virus/physiology , Rats , Vero Cells , Viral Proteins/metabolism , Virulence , Virus Replication
15.
Biologicals ; 38(2): 278-83, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19896867

ABSTRACT

Post-vaccinal encephalitis, although relatively uncommon, is a known adverse event associated with many live, attenuated smallpox vaccines. Although smallpox vaccination ceased globally in 1980, vaccine manufacture has resumed in response to concerns over the possible use of smallpox virus as an agent of bioterrorism. To better support the production of safer smallpox vaccines, we previously reported the development of a mouse model in which a relatively attenuated vaccine strain (Dryvax) could be discerned from a more virulent laboratory strain (WR). Here we have further tested the performance of this assay by evaluating the neurovirulence of several vaccinia virus-based smallpox vaccines spanning a known range in neurovirulence for humans. Our data indicate that testing of 10-100 pfu of virus in mice following intracranial inoculation reliably assesses the virus's neurovirulence potential for humans.


Subject(s)
Encephalomyelitis, Acute Disseminated/diagnosis , Mice , Models, Animal , Smallpox Vaccine/adverse effects , Smallpox Vaccine/therapeutic use , Vaccinia virus/immunology , Animals , Animals, Newborn , Brain/pathology , Brain/virology , Cells, Cultured , Chick Embryo , Chlorocebus aethiops , Drug Evaluation, Preclinical , Encephalomyelitis, Acute Disseminated/etiology , Encephalomyelitis, Acute Disseminated/mortality , Encephalomyelitis, Acute Disseminated/pathology , Time Factors , Vaccinia/complications , Vaccinia/mortality , Vaccinia/pathology , Vaccinia/virology , Vero Cells , Virulence , Virus Replication/physiology
16.
Vaccine ; 27(42): 5822-9, 2009 Sep 25.
Article in English | MEDLINE | ID: mdl-19660591

ABSTRACT

The recent global resurgence of mumps has drawn attention to the continued need for robust mumps immunization programs. Unfortunately, some vaccines derived from inadequately attenuated vaccine strains of mumps virus have caused meningitis in vaccinees, leading to withdrawal of certain vaccine strains from the market, public resistance to vaccination, or in some cases, cessation of national mumps vaccination programs. The most widely implicated mumps vaccine in cases of postvaccination meningitis is derived from the Urabe AM9 strain, which remains in use in some countries. The Urabe AM9 vaccine virus has been shown to exhibit a considerable degree of nucleotide and amino acid heterogeneity. Some studies have specifically implicated variants containing a lysine residue at amino acid position 335 in the hemagglutinin-neuraminidase (HN) protein with neurotoxicity, whereas a glutamic acid residue at this position was associated with attenuation. To test this hypothesis we generated two modified Urabe AM9 cDNA clones coding either for a lysine or a glutamic acid at position 335 in the HN gene. The two viruses were rescued by reverse genetics and characterized in vitro and in vivo. Both viruses exhibited similar growth kinetics in neuronal and non-neuronal cell lines and were of similar neurotoxicity when tested in rats, suggesting that amino acid 335 is not a crucial determinant of Urabe AM9 growth or neurovirulence.


Subject(s)
Amino Acid Substitution , HN Protein/genetics , Mumps Vaccine/genetics , Mumps virus/genetics , Animals , Chlorocebus aethiops , DNA, Complementary/genetics , Humans , Lysine/genetics , Mumps virus/pathogenicity , Mumps virus/physiology , Mutation , RNA, Viral/genetics , Rats , Rats, Inbred Lew , Sequence Analysis, DNA , Vaccines, Attenuated/genetics , Vero Cells , Virulence , Virus Replication
17.
J Neurovirol ; 15(3): 229-37, 2009 May.
Article in English | MEDLINE | ID: mdl-19444697

ABSTRACT

Neurovirulence is one of the pathological complications associated with vaccinia virus (VV) infection/vaccination. Although the viral N1L protein has been identified as the neurovirulence factor, none of the host N1L-interacting factors have been identified so far. In the present study, we identified N1L-interacting proteins by screening a human brain cDNA expression library with N1L as a bait protein in a yeast two-hybrid analysis. The analysis revealed that N1L interacts with human brain-originated cellular basement membrane-associated chondroitin sulfate proteoglycan (bamacan). The N1L-binding domain of bamacan was mapped to its C-terminal 227 amino acids. The N1L-bamacan interaction was further confirmed in both VV-infected and N1L-transfected mammalian cells. Following the confirmation of the protein interactions by coimmunoprecipitation experiments, confocal microscopic analysis revealed that N1L colocalizes with bamacan both in VV-infected B-SC-1 cells as well as in mice neuronal tissue. Furthermore, a human neural cell line, which expresses bamacan to moderately elevated levels relative to a non-neural cell line, supported enhanced viral growth. Overall, these studies clearly suggest that bamacan interacts with the VV-N1L and such interactions seem to play a positive role in promoting the viral growth and perhaps contribute to the virulence of VV in neural cells.


Subject(s)
Brain/virology , Cell Cycle Proteins/metabolism , Chondroitin Sulfate Proteoglycans/metabolism , Chromosomal Proteins, Non-Histone/metabolism , Vaccinia virus/physiology , Vaccinia/virology , Viral Proteins/metabolism , Animals , Animals, Suckling , Brain/metabolism , COS Cells , Cell Cycle Proteins/genetics , Cell Line, Tumor , Chlorocebus aethiops , Chondroitin Sulfate Proteoglycans/genetics , Chromosomal Proteins, Non-Histone/genetics , Host-Pathogen Interactions , Humans , Ligands , Mice , Protein Binding , Vaccinia/metabolism , Vaccinia virus/pathogenicity , Vero Cells
18.
J Neurovirol ; 13(6): 513-21, 2007 Dec.
Article in English | MEDLINE | ID: mdl-18097883

ABSTRACT

Mumps virus is highly neurotropic, with evidence of infection of the central nervous system in more than half of clinical cases. In the prevaccine era, mumps was a major cause of viral meningitis in most developed countries. Despite efforts to attenuate the virus, some mumps vaccines have retained virulence properties and have caused aseptic meningitis in vaccinees, resulting in public resistance to vaccination in some countries. Ensuring the safety of mumps vaccines is an important public health objective, as the need for robust immunization programs has been made clear by the recent resurgence of mumps outbreaks worldwide, including the United States, which in 2006 experienced its largest mumps outbreak in 20 years. To better understand the molecular basis of mumps virus attenuation, the authors developed two infectious full-length cDNA clones for a highly neurovirulent strain of mumps virus. The clones differed at only one site, possessing either an A or G at nucleotide position 271 in the F gene, to represent the heterogeneity identified in the original virulent clinical isolate. In comparison to the clinical isolate, virus rescued from the A-variant cDNA clone grew to higher cumulative titers in vitro but exhibited similar cytopathic effects in vitro and virulence in vivo. In contrast, virus rescued from the G-variant cDNA clone, in comparison to the clinical isolate and the A-variant, was more fusogenic in vitro but replicated to lower cumulative titers and was less neurovirulent in vivo. These data suggest that nucleotide position 271 in the F gene plays a significant role in virus pathogenesis. This infectious clone system will serve as a key tool for further examination of the molecular basis for mumps virus neurovirulence and neuroattenuation.


Subject(s)
DNA, Viral/genetics , Mumps virus/genetics , Mumps virus/pathogenicity , Polymorphism, Single Nucleotide/genetics , Viral Fusion Proteins/genetics , Amino Acid Substitution , Animals , Chlorocebus aethiops , Mumps/pathology , Mumps/physiopathology , Mumps/virology , Vero Cells , Viral Fusion Proteins/metabolism , Virulence/genetics
19.
J Neurovirol ; 11(3): 256-64, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16036805

ABSTRACT

Herpes simplex virus types 1 and 2 (HSV-1, -2) infect and also establish latency in neurons. In the present study, the authors investigated the influence of neuronal activity on the replication of HSV-1. The results showed that the sodium channel blocker tetrodotoxin (TTX) and the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) could significantly increase viral replication in primary neuronal cultures, by two- to fourfold. In contrast, KCl reduced viral production by at least 80% in the same cultures. Inhibitors of GABA(A) receptors completely abolished the effects of GABA. Intravitreously injected TTX in a mouse corneal scarification model enhanced the viral titers > 10-fold in both the trigeminal ganglia and the brain. At 2 h post infection, both TTX and GABA significantly up-regulated the levels of transcription for the viral immediate early (IE) genes ICP0, ICP4, and ICP27, as revealed by real time PCR. These results indicate that the neuronal excitation status may dictate the efficiency of HSV-1 viral replication, probably by regulating the levels of viral IE gene expression. These are the first findings connecting neuronal activity to the molecular mechanisms of HSV replication in the nervous system, which may significantly influence our view of herpesvirus infection and latency.


Subject(s)
Herpes Simplex/virology , Herpesvirus 1, Human/physiology , Neurons/virology , Animals , Brain/virology , Cells, Cultured , Gene Expression/drug effects , Herpes Simplex/metabolism , Immediate-Early Proteins/biosynthesis , Immediate-Early Proteins/genetics , Injections, Intraventricular , Mice , Mice, Inbred BALB C , Neurons/drug effects , Potassium Chloride/pharmacology , Rats , Tetrodotoxin/administration & dosage , Tetrodotoxin/pharmacology , Transcription, Genetic , Trigeminal Ganglion/metabolism , Trigeminal Ganglion/virology , Ubiquitin-Protein Ligases , Virus Replication , gamma-Aminobutyric Acid/pharmacology
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