Dihydrolipoic acid prevents hypoxic/reoxygenation and peroxidative damage in rat heart mitochondria

Fluorescence anisotropy (r) was determined in hypoxic/reoxygenating rat heart mitochondria by means of 1,6-diphenyl-1,3,5-hexatriene. During hypoxia, values for r increased, indicating a rigidified membrane. Membrane fluidity was increased when 20 pmol to 2 nmol/mg protein of dihydrolipoic acid (DHL) was present during hypoxia. Dithiothreitol (DTT) or 2-mercaptopropionylglycin (MPG) at similar concentration did not result in membrane fluidization under these conditions. Peroxidative damage was induced in mitochondria by H2O2. In the presence of 2 nmol/mg protein of DHL, malondialdehyde production was decreased by 50%. DTT or MPG brought about only a 25% decrease. These results were corroborated by spin label studies with 4-maleimido-TEMPO and 5-proxylnonane (5-P-9); H2O2 induced a decrease in fluidity in the region of labeled thiol groups and an increase in polarity sensed by 5-P-9. DHL proved efficient in reducing such fluidity and polarity changes.

The effects of glucose, insulin and metformin on the order parameters of isolated red cell membranes. An electron paramagnetic resonance spectroscopic study

Human red blood cell (RBC) membranes (RBC ghosts) were treated with glucose, insulin and metformin. The order parameters of RBC membranes were determined by 5- and 16-doxyl-stearic acid spin labels. Metabolic effects were excluded using an isolated system of RBC membranes. The membranes were incubated with glucose in physiological (5 mM), renal threshold (10 mM) and manifested diabetic (20 mM) concentrations for limited times. High concentrations of glucose (10, 20, 100 mM) increase the order parameters of RBC membranes significantly. Insulin by itself has a similar effect which is, however, not strictly concentration-dependent. By contrast, metformin at therapeutic concentrations (0.5 and 5.0 microM) decreases the order parameters. At 50 microM concentration the metformin effect is expressed less and recurs at 100 microM concentration. The effects are significant with 5-doxyl-stearic acid, but are not significant with the 16-doxyl derivative. When RBC membranes are co-incubated with 20 mM glucose and metformin at 0.5 and 5.0 microM concentrations the order parameters as determined by 5-doxyl-stearic acid remain normal (= control values). Higher concentrations of metformin (50 and 100 microM) cause an overshoot to very low order parameters. Insulin at 10, 100 and 200 mU/L does not influence significantly the effects of metformin. Addition of physiological amounts of bovine serum albumin does not abolish the effects of metformin. Metformin, at therapeutic concentrations (0.5 and 5.0 microM), maintains the normal fluidity at the polar interface of isolated RBC membranes by counterbalancing non-enzymatic glycosylation with 20 mM glucose in vitro.

Dose/response curves of lipoic acid R-and S-forms in the working rat heart during reoxygenation: superiority of the R-enantiomer in enhancement of aortic flow

Micromolar concentrations of lipoic acid racemate added to a working rat heart during hypoxia have been previously found to improve aortic flow during subsequent reoxygenation. Since the R-form represents the naturally occurring form of lipoic acid, and the S-form does not reveal a positive influence on ATP synthesis in isolated mitoplasts, a dose/response curve of both enantiomers has been performed in working rat hearts. After the end of perfusion mitochondria were isolated and further analysed. At a concentration of 0.05-0.1 mumol of the R-enantiomer, aortic flow rises precipitously during reoxygenation, reaching over 70% of normoxic values compared to 50% of the controls. By contrast, with the S-enantiomer a value of about 60% is attained at 1 mumol, only. Accordingly, ATPase activity in mitochondria isolated from rat hearts previously treated with 0.05-0.1 mumol of the R- or S-enantiomer was significantly decreased or increased respectively. Consequently, whereas mitochondrial ATP synthesis was increased when the R-enantiomer was previously added to the working heart at 0.05-0.1 mumol concentration, with the S-enantiomer ATP synthesis remained within the control range. Mitochondrial membrane fluidity, measured with diphenylhexatriene, revealed a trend towards increase with the R- and decrease with the S-enantiomer. The total amount of thiol added at 0.1 mumol concentration is consistent with a value of 2 nmol/mg mitochondrial protein. This value has previously been found to be connected with -SH groups which add oligomycin-sensitivity to the ATPase complex. It is suggested that oligomycin-sensitive mitochondrial -SH groups contribute to the overall efficiency of low concentrations of lipoic acid R-enantiomer to enhance aortic flow.

Vaccination with recombinant RNA replicon particles protects chickens from H5N1 highly pathogenic avian influenza virus

Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 not only cause a devastating disease in domestic chickens and turkeys but also pose a continuous threat to public health. In some countries, H5N1 viruses continue to circulate and evolve into new clades and subclades. The rapid evolution of these viruses represents a problem for virus diagnosis and control. In this work, recombinant vesicular stomatitis virus (VSV) vectors expressing HA of subtype H5 were generated. To comply with biosafety issues the G gene was deleted from the VSV genome. The resulting vaccine vector VSV*ΔG(HA) was propagated on helper cells providing the VSV G protein in trans. Vaccination of chickens with a single intramuscular dose of 2×10⁸ infectious replicon particles without adjuvant conferred complete protection from lethal H5N1 infection. Subsequent application of the same vaccine strongly boosted the humoral immune response and completely prevented shedding of challenge virus and transmission to sentinel birds. The vaccine allowed serological differentiation of infected from vaccinated animals (DIVA) by employing a commercially available ELISA. Immunized chickens produced antibodies with neutralizing activity against multiple H5 viruses representing clades 1, 2.2, 2.5, and low-pathogenic avian influenza viruses (classical clade). Studies using chimeric H1/H5 hemagglutinins showed that the neutralizing activity was predominantly directed against the globular head domain. In summary, these results suggest that VSV replicon particles are safe and potent DIVA vaccines that may help to control avian influenza viruses in domestic poultry.

One- and two-dimensional electron paramagnetic resonance imaging in skin

EPR imaging with modulated field gradients provides the possibility for obtaining an EPR spectrum in a selected volume. We demonstrate the feasibility of X-band (9.5 GHz) electron paramagnetic resonance (EPR) imaging in skin biopsies of hairless mice. One- (1D) and two-dimensional (2D) EPR images of the persistent free radical di-tertiary-butyl-nitroxide are measured. At a microwave frequency of 9.5 GHz (X-band), 2D images are obtained in skin biopsies with an actual point distinction resolution of 25 microns. In a biological model system, 2D images are measured at L-band frequency (2.0 GHz) with a pixel resolution of 61 microns, and a theoretical spatial resolution of 12.5 microns. In combination with the spin labeling and spin trapping technique, EPR imaging is the most direct approach to analyzing spatial distribution of physicochemical properties in skin, such as membrane fluidity and polarity, as well as detection of free radicals.

Macropinocytosis contributes to hantavirus entry into human airway epithelial cells

Hantaviruses are emerging rodent-borne negative-strand RNA viruses associated with severe human diseases. Zoonotic transmission occurs via aerosols of contaminated rodent excreta and cells of the human respiratory epithelium represent likely early targets. Here we investigated cellular factors involved in entry of the pathogenic Old and New World hantaviruses Hantaan virus (HTNV) and Andes virus (ANDV) into human respiratory epithelial cells. Screening of a kinase inhibitor library using a biocontained recombinant vesicular stomatitis virus pseudotype platform revealed differential requirement for host kinases for HTNV and ANDV entry and provided first hints for an involvement of macropinocytosis. Examination of a selected panel of well-defined inhibitors of endocytosis confirmed that both HTNV and ANDV enter human respiratory epithelial cells via a pathway that critically depends on sodium proton exchangers and actin, hallmarks of macropinocytosis. However, HTNV and ANDV differed in their individual requirements for regulatory factors of macropinocytosis, indicating virus-specific differences.

Human glomerular mesangial cells inactivate leukotriene B4 by reduction into dihydro-leukotriene B4 metabolites

Due to its potent chemotactic properties leukotriene B4 is an important mediator of inflammatory reactions. Cultured human kidney mesangial cells converted exogenously added leukotriene B4 efficiently into three different more lipophilic metabolites, two of them probably representing dihydro-leukotriene B4 isomers. This represents an alternative metabolic pathway, in contrast to leukotriene B4 omega-oxidation found in human polymorphonuclear leukocytes. Both dihydro-leukotriene B4 isomers had nearly completely lost their ability to induce leukocyte chemotaxis as compared to leukotriene B4.

The surface glycoprotein E2 of bovine viral diarrhoea virus contains an intracellular localization signal

The intracellular transport of the surface glycoprotein E2 of bovine viral diarrhoea virus was analysed by expressing the cloned gene in the absence of other viral proteins. Immunofluorescence analysis and surface biotinylation indicated that E2 is located in an early compartment of the secretory pathway and not transported to the cell surface. In agreement with this result, E2 was found to contain only high-mannose oligosaccharide side-chains but no N-glycans of the complex type. To define the intracellular localization signal of the E2 protein, chimeric proteins were generated. E2 chimeras containing the MT (membrane anchor plus carboxy-terminal domain) of the G protein of vesicular stomatitis virus (VSV) or of the F protein of bovine respiratory syncytial virus (BRSV) were transported to the cell surface. On the other hand, VSV G protein containing the MT domain of E2 was detected only in the ER, indicating that this domain contains an ER localization signal. A chimeric E2 protein, in which not the membrane anchor but only the carboxy-terminal end was replaced by the corresponding domain of the BRSV F protein, was also localized in the ER. Therefore, it was concluded that the membrane anchor contains the ER localization signal of E2. Interestingly, the ER export signal within the VSV G protein cytoplasmic tail was found to overrule the ER localization signal in the E2 protein membrane anchor.

Enzyme release from chick myocytes during hypoxia and reoxygenation: dependence on pH

On reoxygenation of ischemic or hypoxic hearts a sudden release of cytosolic enzymes coupled with hypercontraction and cell injury occurs, which has been termed the "oxygen paradox". We have attempted to imitate this phenomenon in cultured chick myocytes to try to find the cause of this sudden enzyme release. During 4 hours of normoxic perfusion (pH 7.4) monolayer cultures of chick embryonic myocytes retain their normal morphology, beat rhythmically, and show no release of creatine kinase (CK) into the perfusate. Hypoxic perfusion (O2 less than or equal to 0.25 microliter/ml) stops cell contraction (15-20 min) and causes "blebbing" of the sarcolemma (20-30 min). Membrane blebs increase in size and number with continuing hypoxia and eventually the cells become irreversibly damaged. Perfusion at pH 7.4 leads to a release of CK shortly after membrane damage occurs (30-40 min), with peak enzyme levels at 60-90 min. Reoxygenation after 120 min hypoxia does not exacerbate release. Hypoxic perfusion at pH 7.0 suppresses the release of CK from the cells despite extensive membrane blebbing. Normoxic perfusion at pH 7.4 after 100 min hypoxia (pH 7.0) causes an efflux of enzyme from the irreversibly injured cells. This can be prevented by reoxygenating the cells at pH 7.0 and stimulated by raising the pH of the hypoxic perfusate to 7.4. Shorter hypoxic periods (30 mins) at pH 7.0 followed by normoxic perfusion at pH 7.4 lead to a sudden large efflux of CK, arrhythmic contractions and hypercontraction of myofilaments, i.e. the typical symptoms of the "oxygen paradox". Thus changes in external pH can influence the release of intracellular enzymes during hypoxia and reoxygenation.

Gradual changes in permeability of inner mitochondrial membrane precede the mitochondrial permeability transition

Some compounds are known to induce solute-nonselective permeability of the inner mitochondrial membrane (IMM) in Ca2+-loaded mitochondria. Existing data suggest that this process, following the opening of a mitochondrial permeability transition pore, is preceded by different solute-selective permeable states of IMM. At pH 7, for instance, the K0.5 for Ca2+-induced pore opening is 16 microM, a value 80-fold above a therapeutically relevant shift of intracellular Ca2+ during ischemia in vivo. The present work shows that in the absence of Ca2+, phenylarsine oxide and tetraalkyl thiuram disulfides (TDs) are able to induce a complex sequence of IMM permeability changes. At first, these agents activated an electrogenic K+ influx into the mitochondria. This K+-specific pathway had K0.5 = 35 mM for K+ and was inhibited by bromsulfalein with Ki = 2.5 microM. The inhibitors of mitochondrial KATP channel, ATP and glibenclamide, did not inhibit K+ transport via this pathway. Moreover, 50 microM glibenclamide induced by itself K+ influx into the mitochondria. After the increase in K+ permeability of IMM, mitochondria become increasingly permeable to protons. Mechanisms of H+ leak and nonselective permeability increase could also be different depending on the type of mitochondrial permeability transition (MPT) inducer. Thus, permeabilization of mitochondria induced by phenylarsine oxide was fully prevented by ADP and/or cyclosporin A, whereas TD-induced membrane alterations were insensitive toward these inhibitors. It is suggested that MPT in vivo leading to irreversible apoptosis is irrelevant in reversible ischemia/reperfusion injury.

Small and large unilamellar vesicle membranes as model system for bile acid diffusion in hepatocytes

Uptake of bile acids into the liver cell occurs via active transport or passive diffusion. In a model system, passive diffusion was studied in liposomes using pyranine fluorescence. Rate constants for the diffusion of diverse more polar or more apolar bile acids were examined. Hydrophobic lithocholic acid (LCA) revealed a maximal rate constant of 0.057 s(-1); with the polar ursodeoxycholic acid (UDCA), the value was 0.019 s(-1). UDCA (3 mol%) effectively decreased the rate constant of 0.1 mM chenodeoxycholic acid (CDCA), whereas cholesterol reached a similar decrease only between 5 and 10 mol%. At higher concentrations of CDCA (above 1 mM) or LCA (0.3-0.4 mM), breaking up of liposomal structure was confirmed by light-scattering decrease and increase of carboxyfluorescein fluorescence. Changes in lipid composition of phosphatidylcholine (PC)- small unilamellar vesicles (SUVs) or large unilamellar vesicles (LUVs) also caused decreasing rate constants. For a cardiolipin (CL):PC ratio of 1:20 the CDCA (0.1 mM) rate constant was 71% lower (0.015 s(-1)) and for a sphingomyelin (SM):PC ratio of 2:1 the rate constant was 50% lower (0.026 s(-1)). Changes in membrane fluidity were detected using membrane anisotropy measurements with the 1,6-diphenyl-1,3, 5-hexatriene (DPH) method. Membrane fluidity was reduced with cholesterol- but not with CL- or SM-containing SUVs (ratio: cholesterol, CL, SM:PC of 1:5). This model system is currently used for the analysis of more complex lipid vesicles resembling the plasma/hepatocyte membrane, which is either stabilized or destabilized by appropriate conditions. The results should become clinically relevant.

Oxidation-sensitive polymersomes as vaccine nanocarriers enhance humoral responses against Lassa virus envelope glycoprotein

Lassa virus (LASV) causes severe hemorrhagic fever with high mortality, yet no vaccine currently exists. Antibodies targeting viral attachment proteins are crucial for protection against many viral infections. However, the envelope glycoprotein (GP)-1 of LASV elicits weak antibody responses due to extensive glycan shielding. Here, we explored a novel vaccine strategy to enhance humoral immunity against LASV GP1. Using structural information, we designed a recombinant GP1 immunogen, and then encapsulated it into oxidation-sensitive polymersomes (PS) as nanocarriers that promote intracellular MHCII loading. Mice immunized with adjuvanted PS (LASV GP1) showed superior humoral responses than free LASV GP1, including antibodies with higher binding affinity to virion GP1, increased levels of polyfunctional anti-viral CD4 T cells, and IgG-secreting B cells. PS (LASV GP1) elicited a more diverse epitope repertoire of anti-viral IgG. Together, these data demonstrate the potential of our nanocarrier vaccine platform for generating virus-specific antibodies against weakly immunogenic viral antigens.

Vesicular stomatitis virus replicon expressing the VP2 outer capsid protein of bluetongue virus serotype 8 induces complete protection of sheep against challenge infection

Bluetongue virus (BTV) is an arthropod-borne pathogen that causes an often fatal, hemorrhagic disease in ruminants. Different BTV serotypes occur throughout many temperate and tropical regions of the world. In 2006, BTV serotype 8 (BTV-8) emerged in Central and Northern Europe for the first time. Although this outbreak was eventually controlled using inactivated virus vaccines, the epidemic caused significant economic losses not only from the disease in livestock but also from trade restrictions. To date, BTV vaccines that allow simple serological discrimination of infected and vaccinated animals (DIVA) have not been approved for use in livestock. In this study, we generated recombinant RNA replicon particles based on single-cycle vesicular stomatitis virus (VSV) vectors. Immunization of sheep with infectious VSV replicon particles expressing the outer capsid VP2 protein of BTV-8 resulted in induction of BTV-8 serotype-specific neutralizing antibodies. After challenge with a virulent BTV-8 strain, the vaccinated animals neither developed signs of disease nor showed viremia. In contrast, immunization of sheep with recombinant VP5 - the second outer capsid protein of BTV - did not confer protection. Discrimination of infected from vaccinated animals was readily achieved using an ELISA for detection of antibodies against the VP7 antigen. These data indicate that VSV replicon particles potentially represent a safe and efficacious vaccine platform with which to control future outbreaks by BTV-8 or other serotypes, especially in previously non-endemic regions where discrimination between vaccinated and infected animals is crucial.

Decrease of red cell membrane fluidity and -SH groups due to hyperglycemic conditions is counteracted by alpha-lipoic acid

Human red cell membranes (ghosts) were treated by 5 min of incubation with fasting or hypo- and hyperglycemic concentrations of D-glucose. This simulation of nondiabetic or diabetic conditions revealed an influence on membrane fluidity and on protein -SH reactivity. Protein -SH groups, measured with Ellman's reagent, generally behave in the same way as membrane fluidity determined with diphenylhexatriene. Maximal values were obtained with 5 mM D-glucose, whereas decrease was observed above 10 mM D-glucose. Addition of alpha-lipoic acid (4 nmol/mg protein) resulted in a significant increase in membrane fluidity and titratable -SH groups at glucose concentrations of 10 mM and above. Dithiothreitol diminished titrable-SH groups and did not restore membrane fluidity. 2-Mercaptopropionylglycine was only effective in restoration of -SH groups. By contrast to D-glucose, other sugars such as L-glucose, D-fructose, or sucrose revealed no comparable changes on membrane fluidity and titratable membrane -SH groups between concentrations of 5 and 10 mM. The hyperglycemic effects of D-glucose were corroborated with isolated, reconstituted membrane proteins and erythrocyte glucose carrier, indicating that, in general, the observed divergent biochemical/biophysical changes of the red cell membrane are influenced by the glucose transport protein GluT1. The natural R-form and the S-form of alpha-lipoic acid were compared with racemic R-/S-forms for their efficiencies in alterations of red cell membrane fluidity. Decreased fluidities in presence of 10 mM glucose were found to be influenced in differentiated ways: the S-form was highly active in increasing fluidity at 4 nmol/mg and increasingly less active up to 20 nmol/mg protein. By contrast the R-form of lipoic acid was moderately efficient in increasing fluidity through a larger concentration range between 4 and 80 nmol/mg protein.

The cell receptor level is reduced during persistent infection with influenza C virus

Persistent influenza C virus infection of MDCK cells perpetuates the viral genome in a cell-associated form. Typically, virus production remains at a low level over extended periods, in the absence of lytic effects of replication. In this study, we demonstrate that persistently infected cells are very restricted in permissiveness for superinfection. By reconstitution experiments, using bovine brain gangliosides as artificial receptors, the degree of super-infection was markedly increased. Analysis of cellular receptor expression revealed reduced concentrations of sialoglycoproteins in general and a limited presentation of the major receptor gp40. Cocultures of persistently infected and uninfected cells (the latter carrying normal receptor levels) initiated a transient rise in virus titers. This kind of induction of virus synthesis appeared to be mainly receptor-linked, since a receptor-deprived subline, MDCK II, did not give rise to a similar effect. Susceptibility of MDCK II cocultures could be partly restored by ganglioside treatment. In accordance to related virus systems, these findings on influenza C virus suggest a role of cell receptor concentrations in the regulation of long-term persistence.

Use of benchmarking techniques to justify the evolution of antibiotic management programs in healthcare systems

OBJECTIVE

To apply basic benchmarking techniques to hospital antibiotic expenditures and clinical pharmacy personnel and their duties, to identify cost savings strategies for clinical pharmacy services.

DESIGN

Prospective survey of 18 hospitals ranging in size from 201 to 942 beds. Each was asked to provide antibiotic expenditures, an overview of their clinical pharmacy services, and to describe the duties of clinical pharmacists involved in antibiotic management activities. Specific information was sought on the use of pharmacokinetic dosing services, antibiotic streamlining, and oral switch in each of the hospitals.

RESULTS

Most smaller hospitals (< 300 beds) did not employ clinical pharmacists with the specific duties of antibiotic management or streamlining. At these institutions, antibiotic management services consisted of formulary enforcement and aminoglycoside and/or vancomycin dosing services. The larger hospitals we surveyed employed clinical pharmacists designated as antibiotic management specialists, but their usual activities were aminoglycoside and/or vancomycin dosing services and formulary enforcement. In virtually all hospitals, the yearly expenses for antibiotics exceeded those of Millard Fillmore Hospitals by $2,000-3,000 per occupied bed. In a 500-bed hospital, this difference in expenditures would exceed $1.5 million yearly. Millard Fillmore Health System has similar types of patients, but employs clinical pharmacists to perform streamlining and/or switch functions at days 2-4, when cultures come back from the laboratory.

CONCLUSIONS

The antibiotic streamlining and oral switch duties of clinical pharmacy specialists are associated with the majority of cost savings in hospital antibiotic management programs. The savings are considerable to the extent that most hospitals with 200-300 beds could readily cost-justify a full-time clinical pharmacist to perform these activities on a daily basis. Expenses of the program would be offset entirely by the reduction in the actual pharmacy expenditures on antibiotics.

Accidental mechanical asphyxia of children in Germany between 2000 and 2008

Accidents constitute one of the greatest risks to children, yet there are few medical reports that discuss the subject of accidental asphyxia. However, a systematic analysis of all documented cases in Germany over the years 2000-2008 has now been conducted, aiming at identifying patterns of accidental asphyxia, deducing findings, defining avoidance measures and recommending ways of increasing product safety and taking possible precautions. The analysis is based on a detailed retrospective analysis of all 91 relevant autopsy reports from 24 different German forensic institutes. A variety of demographic and morphological data was systematically collected and analysed. In 84 of the 91 cases, the sex of the victim was reported, resulting in a total of 57 boys (68 %) and 27 girls (32 %). The age spread ranged between 1 day and 14 years, with an average of 5.9 years. Most accidents occurred in the first year of life (20 %) or between the ages of 1 and 2 years (13 %). In 46 % of cases, the cause of death was strangulation, with the majority occurring in the home environment. In 31 % of all cases, the cause of death was positional asphyxia, the majority resulting from chest compression. In 23 % of cases, the cause of death was aspiration, mainly of foreign bodies. Today, accidental asphyxiation is a rare cause of death in children in Germany. Nevertheless, the majority of cases could have been avoided. Future incidence can be reduced by implementing two major precautions: increasing product safety and educating parents of potentially fatal risks. Specific recommendations relate to children's beds, toys and food.

Bromobimane crosslinking studies in oligomycin-sensitive ATPase from beef heart mitochondria. Mr 31 000 protein crosslinked

Using a bromobimane fluorescent label the Mr 31 000 protein band oligomycin-sensitive (OS)-ATPase from beef heart mitochondria is shown to become much intensified by 2-mercaptopropionylglycine. In the presence of 3.5 nmol/mg protein of the thiol reagent ATP-Pi exchange activity is increased by 90%. With the fluorescent crosslinking reagent dibromobimane (DB) we show that a new fluorescent peak appears between Mr 50 000 and 60 000. ATP-Pi exchange is very much decreased by DB. The results suggest that for regulation of ATP-synthetase activity sulfhydryl groups in the region of the Mr 31 000 protein(s) play an important role.

Quantification of Lyssavirus-Neutralizing Antibodies Using Vesicular Stomatitis Virus Pseudotype Particles

Rabies is a highly fatal zoonotic disease which is primarily caused by rabies virus (RABV) although other members of the genus Lyssavirus can cause rabies as well. As yet, 14 serologically and genetically diverse lyssaviruses have been identified, mostly in bats. To assess the quality of rabies vaccines and immunoglobulin preparations, virus neutralization tests with live RABV are performed in accordance with enhanced biosafety standards. In the present work, a novel neutralization test is presented which takes advantage of a modified vesicular stomatitis virus (VSV) from which the glycoprotein G gene has been deleted and replaced by reporter genes. This single-cycle virus was trans-complemented with RABV envelope glycoprotein. Neutralization of this pseudotype virus with RABV reference serum or immune sera from vaccinated mice showed a strong correlation with the rapid fluorescent focus inhibition test (RFFIT). Importantly, pseudotype viruses containing the envelope glycoproteins of other lyssaviruses were neutralized by reference serum to a significantly lesser extent or were not neutralized at all. Taken together, a pseudotype virus system has been successfully developed which allows the safe, fast, and sensitive detection of neutralizing antibodies directed against different lyssaviruses.

Primary pleomorphic adenoma of the external auditory canal diagnosed by fine needle aspiration cytology. A case report

BACKGROUND

Pleomorphic adenoma (PA) arising in the external auditory canal (EAC) is a very rare neoplasm, thought to be derived from ceruminous glands.

CASE

A 43-year-old male presented with a slowly growing mass in the right EAC. Clinical and radiologic examinations showed a well-circumscribed tumor limited to the EAC, without a connection to the parotid gland. Fine needle aspiration cytology (FNAC) revealed the typical cytologic findings of PA. The diagnosis was confirmed by histologic examination.

CONCLUSION

This case illustrates that together with clinical and radiologic findings, primary PA of the EAC can confidently be diagnosed by FNAC.