Visual Immunoprecipitate Assay (VIP) for Listeria monocytogenes and Related Listeria Species Detection in Selected Foods: Collaborative Study

Six foods representing a variety of food products were analyzed by the Assurance Listeria polyclonal enzyme immunoassay (EIA) and by either the Bacteriological Analytical Manual or the U.S. Department of Agriculture culture method for detecting Listeria monocytogenes and related Listeria species. Samples of each food type, at each inoculation level, were analyzed simultaneously by both methods. A total of 19 laboratories representing federal government agencies and private industry in the United States and Canada participated. Food types were inoculated with Listeria species including L. monocytogenes, with the exception of 3 lots of green beans, which were naturally contaminated. During this study, 1764 samples and controls were analyzed and confirmed, of which 492 were positive and 947 were negative by both methods. There were 159 samples that were positive by culture method but negative by the EIA and 188 that were negative by culture method but positive by EIA. Twenty-two samples were negative by EIA and by culture method but confirmed positive when Assurance selective enrichment broths were subcultured to selective agar. The Assurance polyclonal EIA for detecting L. monocytogenes and related Listeria species in foods has been adopted first action by AOAC INTERNATIONAL.

Assurance Polyclonal Enzyme Immunoassay for Detection of Listeria monocytogenes and Related Listeria Species in Selected Foods: Collaborative Study

Six foods representing a variety of food products were analyzed by the Assurance Listeria polyclonal enzyme immunoassay (EIA) and by either the Bacteriological Analytical Manual or the U.S. Department of Agriculture culture method for detecting Listeria monocytogenes and related Listeria species. Samples of each food type, at each inoculation level, were analyzed simultaneously by both methods. A total of 19 laboratories representing federal government agencies and private industry in the United States and Canada participated. Food types were inoculated with Listeria species including L. monocytogenes, with the exception of 3 lots of green beans, which were naturally contaminated. During this study, 1764 samples and controls were analyzed and confirmed, of which 492 were positive and 947 were negative by both methods. There were 159 samples that were positive by culture method but negative by the EIA and 188 that were negative by culture method but positive by EIA. Twenty-two samples were negative by EIA and by culture method but confirmed positive when Assurance selective enrichment broths were subcultured to selective agar. The Assurance polyclonal EIA for detecting L. monocytogenes and related Listeria species in foods has been adopted first action by AOAC INTERNATIONAL.

Coinfection of sheep with Anaplasma, Theileria and Babesia species in the Kurdistan Region, Iraq

Infections of small ruminants with Anaplasma, Theileria and Babesia species are widely distributed in the old world and are of great economic impact. In Iraq, data on disease occurrence in sheep caused by above-mentioned infectious agents are scarce. This study provides information on various haemoparasitic agents infecting sheep in the Kurdistan Region, Iraq, using molecular diagnostic tools. Altogether, 195 samples originating from three governorates in the Kurdistan Region, namely Duhok, Erbil and Sulaimaniya, were analysed. The following pathogens were identified: Anaplasma ovis (62.6%), Theileria ovis (14.35%), T. lestoquardi (7.7%), T. uilenbergi (5.6%) and Babesia ovis (1.5%). T. uilenbergi is detected for the first time in Iraq. Coinfection of sheep with different pathogens could be observed in this study, and it was found that 45 of 195 (23%) of the samples contained more than one pathogen. Even triple-positive samples were identified in 3% of the investigated animals. In conclusion, we confirm the coinfection of sheep with various haemoparasitic pathogen species in the Kurdistan Region of Iraq. Further investigations are needed to reveal the epidemiology of the diseases, the respective tick vectors, and, in the case of coinfection, pathogens' interaction and possible cross-protection.

Identification and partial characterization of a Salp15 homolog from Ixodes ricinus

The immunomodulatory molecule Salp15 is originally described in Ixodes scapularis and has been shown to inhibit CD4 T cell activation. Many Salp15 homologs have been described from Ixodes species, and all were well conserved at C-terminal residues that seem to be essential for the function of the protein. In this study, a gene sequence was amplified from cDNA isolated from engorged female I. ricinus ticks, which was predicted to generate a protein of 12.3 kDa. The protein displayed distinct amino acid differences from previously described I. ricinus Salp15 homologs, with amino acid identity ranging between 46.6% and 93.9%. It was referred to as I. ricinus Salp15-like protein. The protein showed 48.1% sequence identity to I. scapularis Salp15. We analyzed the effect of the recombinant I. ricinus Salp15-like protein on the production of cytokines from human peripheral blood mononuclear cells stimulated with LPS. The recombinant protein exerted no effect on the production of TNF-α and IL-6, but the production of IL-10 was dose-dependently reduced. It can be concluded that I. ricinus Salp15-like protein exerts an immunomodulatory effect on the host. The inhibition of IL-10 production may possibly lead to a retardation of B cell activity.

Histological, cytological and biochemical alterations induced by microcystin-LR and cylindrospermopsin in white mustard (Sinapis alba L.) seedlings

This study compares the histological, cytological and biochemical effects of the cyanobacterial toxins microcystin-LR (MCY-LR) and cylindrospermopsin (CYN) in white mustard (Sinapis alba L.) seedlings, with special regard to the developing root system. Cyanotoxins induced different alterations, indicating their different specific biochemical activities. MCY-LR stimulated mitosis of root tip meristematic cells at lower concentrations (1 μg ml-1) and inhibited it at higher concentrations, while CYN had only inhibitory effects. Low CYN concentrations (0.01 μg ml-1) stimulated lateral root formation, whereas low MCY-LR concentrations increased only the number of lateral root primordia. Both inhibited lateral root development at higher concentrations. They induced lignifications, abnormal cell swelling and inhibited xylem differentiation in roots and shoots. MCY-LR and CYN induced the disruption of metaphase and anaphase spindles, causing altered cell divisions. Similar alterations could be related to decreased protein phosphatase (PP1 and PP2A) activities in shoots and roots. However, in vitro phosphatase assay with purified PP1 catalytic subunit proved that CYN in contrast to MCY-LR, decreased phosphatase activities of mustard in a non-specific way. This study intends to contribute to the understanding of the mechanisms of toxic effects of a protein phosphatase (MCY-LR) and a protein synthesis (CYN) inhibitory cyanotoxin in vascular plants.

Cylindrospermopsin and microcystin-LR alter the growth, development and peroxidase enzyme activity of white mustard (Sinapis alba L.) seedlings, a comparative analysis

This work focuses on the comparative analysis of the effects of two cyanobacterial toxins of different chemical structure cylindrospermopsin (CYN) and microcystin-LR (MC-LR) on the white mustard (Sinapis alba L.) seedlings. Both cyanotoxins reduced significantly the fresh mass and the length of cotyledons, hypocotyls and main roots of seedlings in a concentration dependent manner. For various mustard organs the 50% inhibitory concentration values (IC50) of growth were between 3-5 μg ml(-1) for MC-LR and between 5-10 μg ml-1 for CYN, respectively. Cyanotoxins altered the development of cotyledons, the accumulation of photosynthetically active pigments and anthocyanins. Low MC-LR concentrations (0.01 and 0.1 μg ml(-1)) stimulated anthocyanin formation in the cotyledons but higher than 1 μg ml(-1) MC-LR concentrations strongly inhibited it. The CYN treated chlorotic cotyledons were violet coloured in consequence of high level of anthocyanins, while MC-LR induced chlorosis was accompanied by the appearance of necrotic patches. Necrosis and increases of peroxidase enzyme activity (POD) are general stress responses but these alterations were characteristic only for MC-LR treated mustard plants. These findings provide experimental evidences of developmental alterations induced by protein synthesis and protein phosphatase inhibitory cyanotoxins (CYN and MC-LR) in a model dicotyledonous plant.

Maternal smoking promotes chronic obstructive lung disease in the offspring as adults

INTRODUCTION

In utero and/or childhood environmental tobacco smoke exposure is well known to adversely affect lung function and to depreciate child's health in many ways. Fewer studies have assessed the long-term effects on COPD development and disease severity in later adulthood.

METHODS

COPD patients were interviewed using a structured questionnaire regarding their personal as well as the smoking habits of their parents. Data were compared with the disease history, e.g. COPD exacerbation rate, and their lung function data.

RESULTS

Between 2003 and 2004 COPD patients were recruited a) in a private practice specialized in pulmonary medicine (n = 133) and b) in a hospital (n = 158). 75% of their fathers and only 15.4 of all mothers smoked regularly. COPD patients from smoking mothers had lower FEV1 predicted than those raised in household without maternal smoking exposure: 39.4 +/- 9.5% vs. 51.9 +/- 6.0% (P = 0.037). Fathers had no effect on FEV1 regardless if they are smokers or non-smokers. Rate of severe exacerbations requiring hospitalization remained unaffected by parental second hand smoke exposure.

CONCLUSION

Maternal smoking negatively affects lung function of their offspring even in late adulthood when they develop COPD. It even aggravates the cumulative effect of active cigarette consumption. Clinical course of the COPD remained unaffected.

Cytoplasmic sequestration of p53 promotes survival in leukocytes transformed by Theileria

The function of the p53 protein as the central effector molecule of the p53 apoptotic pathway was investigated in a reversible model of epigenetic transformation. The infection of bovine leukocytes by the intracellular protozoan parasite Theileria annulata results in parasite-dependent transformation and proliferation of the host cells. We found p53 to be largely localized in the host cell cytoplasm and associated with the parasite membrane of isolated schizonts. Curing infected cells of the parasite with the theilericidal drug buparvaquone resulted in a time-dependent translocation of p53 into the host cell nucleus and the upregulation of the proapoptotic Bax and Apaf-1 and the downregulation of the anti-apoptotic Bcl-2 proteins. Although buparvaquone treatment led to apoptosis of the host cell, inhibition of either p53 or Bax significantly reduced buparvaquone-induced apoptosis of the transformed cells. Thus, the p53 apoptotic pathway of host cells is not induced by infection and transformation with Theileria by a mechanism involving cytoplasmic sequestration of p53. The close association of host cell p53 with the parasite membrane implies that the parasite either interacts directly with p53 or mediates cytoplasmic sequestration of p53 by interacting with other host cell proteins regulating p53 localization.

Pharmacokinetic interaction between verapamil and everolimus in healthy subjects

AIMS

We sought to define the influence of verapamil, an inhibitor of CYP3A and P-glycoprotein, on the pharmacokinetics of everolimus, a substrate of this enzyme and transporter.

METHODS

This was a two-period, single-sequence, crossover study in 16 healthy subjects. In period 1 subjects received a single 2 mg oral dose of everolimus. In period 2 they received verapamil 80 mg three times daily for a total of 6 days and a single 2 mg dose of everolimus co-administered on the second day of verapamil therapy.

RESULTS

During verapamil co-administration, everolimus C(max) increased 2.3-fold (90% CI, 1.9, 2.7) from 21 +/- 8 to 47 +/- 18 ng ml(-1) and AUC increased 3.5-fold (90% CI, 3.1, 3.9) from 115 +/- 45 to 392 +/- 142 ng ml(-1) h. Everolimus half-life was only prolonged to a minor extent (32 +/- 6 vs. 37 +/- 6 h). Verapamil predose concentrations doubled from 32 +/- 16 to 74 +/- 42 ng ml(-1) after single dose administration of everolimus.

CONCLUSIONS

Multiple dosing with verapamil increased blood concentrations of everolimus after a single dose by an average 3.5-fold. During verapamil treatment, dose reduction for everolimus should be made guided by blood monitoring and for verapamil by blood pressure monitoring.

DAVID—a translucent multi-wire transmission ionization chamber forin vivoverification of IMRT and conformal irradiation techniques

Permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution, positioned on the radiation entrance side of the patient, has not been clinically available so far. In this work we present the DAVID system, which is able to perform this quality assurance measurement while the patient is treated. The DAVID system is a flat, multi-wire transmission-type ionization chamber, placed in the accessory holder of the linear accelerator and constructed from translucent materials in order not to interfere with the light field. Each detection wire of the chamber is positioned exactly in the projection line of a MLC leaf pair, and the signal of each wire is proportional to the line integral of the ionization density along this wire. Thereby, each measurement channel essentially presents the line integral of the ionization density over the opening width of the associated leaf pair. The sum of all wire signals is a measure of the dose-area product of the transmitted photon beam and of the total radiant energy administered to the patient. After the dosimetric verification of an IMRT plan, the values measured by the DAVID system are stored as reference values. During daily treatment the signals are re-measured and compared to the reference values. A warning is output if there is a deviation beyond a threshold. The error detection capability is a leaf position error of less than 1 mm for an isocentric 1 cm x 1 cm field, and of 1 mm for an isocentric 20 cm x 20 cm field.

Development of a recombinant indirect ELISA for the diagnosis of Theileria sp. (China) infection in small ruminants

Theileria sp. (China) causes severe limitations on the development of the livestock industry in the north-west of China. An enzyme-linked immunosorbent assay (ELISA) based on merozoite homogenate of the parasite for diagnosis of infection has been established; however, cross-reactivity with other small ruminant-infecting piroplasms could not be excluded. Thus, a prerequisite for epidemiological surveys and diagnosis was the establishment of a recombinant protein-based ELISA. To this end, serum from Theileria sp. (China)-infected sheep was used to screen a Theileria lestoquardi expression library, resulting in the identification of a specifically reacting clone with a high identity to the heat shock protein 70 (HSP70) of Theileria parva and Theileria annulata and thus named TlHSP70. An HSP70 homologue was also confirmed to be expressed by Theileria sp. (China) merozoites (TcHSP70). A part of the TlHSP70 protein, found to be conserved in TcHSP70, was recombinantly expressed and used to establish an ELISA. A total of 260 field serum samples tested resulted in a sensitivity and specificity of 94.3 and 89.5%, respectively, in comparison with the merozoite homogenate ELISA. The potentials of the application of the test in epidemiological surveys to map out the prevalence of the disease and for routine diagnostics are described.

Blood concentrations of everolimus are markedly increased by ketoconazole

The authors sought to quantify the influence of the CYP3A and P-glycoprotein inhibitor ketoconazole on the pharmacokinetics of everolimus in healthy subjects. This was a 2-period, single-sequence, crossover study in 12 healthy subjects. In period 1, subjects received the reference treatment of a single 2-mg dose of everolimus. In period 2, they received the test treatment of ketoconazole 200 mg twice daily for a total of 8 days and a single dose of everolimus coadministered on the fourth day of ketoconazole therapy. The test/reference ratio and 90% confidence interval were derived for everolimus maximum concentration and area under the curve. During ketoconazole coadministration, everolimus maximum concentration increased 3.9-fold (90% confidence interval, 3.4-4.6) from 15 +/- 4 ng/mL to 59 +/- 13 ng/mL. Everolimus area under the curve increased 15.0-fold (90% confidence interval, 13.6-16.6) from 90 +/- 23 ng*h/mL to 1324 +/- 232 ng*h/mL. Everolimus half-life was prolonged by 1.9-fold from 30 +/- 4 hours to 56 +/- 5 hours. Everolimus did not appear to alter ketoconazole predose concentrations. Given the magnitude of this drug interaction, use of ketoconazole should be avoided if possible in everolimus-treated patients.

The streptogramin antibiotics: update on their mechanism of action

Antibiotics of the streptogramin class are an association of two types of chemically different compounds, group A molecules and group B molecules, acting in synergy. The combination of these molecules generally inhibits bacterial growth at a lower concentration than does either the group A or group B molecule alone and is often bactericidal against strains of bacteria for which each type of molecule alone is only bacteriostatic. The semisynthetic streptogramin quinupristin/dalfopristin (RP 59500), the first water-soluble member of this class, is under development for the treatment of severe infections caused by methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, penicillin-resistant Streptococcus pneumoniae, glycopeptide-resistant Enterococcus faecium, and other organisms. The streptogramins block the translation of mRNA into protein. Both group A and group B molecules bind to the peptidyl-transferase domain of the bacterial ribosome. The group B molecule stimulates the dissociation of peptidyl-tRNA from the ribosome and may interfere with the passage of the completed polypeptide away from the peptidyl-transferase centre. The group A molecule inhibits the elongation of the polypeptide chain by preventing both the binding of aminoacyl-tRNA to the ribosomal A site and the formation of the peptide bond. When the two types of molecule are used in combination, the binding of the group A molecule alters the conformation of the ribosome such that the affinity of the ribosome for the B molecule is increased. This accounts, in part or entirely, for the observed synergy. This synergy is unaffected by ribosomal modifications conferring resistance to the macrolides, lincosamides, and group B molecules alone.

Effect of multiple-dose erythromycin on everolimus pharmacokinetics

OBJECTIVE

We sought to quantify the influence of the CYP3A inhibitor erythromycin on the pharmacokinetics of everolimus, a CYP3A substrate.

METHODS

This was a two-period, single-sequence, crossover study in 16 healthy subjects. In period 1, subjects received the reference treatment of a single 2-mg dose of everolimus. In period 2, they received the test treatment of erythromycin 500 mg three times daily for a total of 9 days and a single 2-mg dose of everolimus coadministered on the fifth day of erythromycin therapy. The test/reference ratio and 90% confidence interval (CI) were derived for everolimus C (max) and AUC.

RESULTS

During erythromycin coadministration, everolimus C (max) increased 2.0-fold (90% CI, 1.8-2.3) from 20+/-5 ng/ml to 40+/-10 ng/ml. Everolimus AUC increased 4.4-fold (90% CI, 3.5-5.4) from 116+/-37 ng h/ml to 524+/-225 ng h/ml. Everolimus half-life was prolonged by 39% from 32+/-6 h to 44+/-6 h. Erythromycin predose concentrations were not changed after single-dose administration of everolimus.

CONCLUSION

Multiple-dose erythromycin increased single-dose everolimus blood levels by an average 4.4-fold (range, 2.0-12.6). During erythromycin treatment, a compensatory everolimus dose reduction should be made guided by everolimus therapeutic drug monitoring.

Ribosomal alterations contribute to bacterial resistance against the dipeptide antibiotic TAN 1057

TAN 1057-resistant Staphylococcus aureus and Escherichia coli strains were selected to elucidate the mechanism of resistance and the mode of action of this dipeptide antibiotic. Cell-free translation with isolated ribosomes and S150 fractions from sensitive and resistant S. aureus strains demonstrated that alterations in the ribosomes contribute to the resistance of the bacteria.

Application of the recombinant Theileria annulata surface protein in an indirect ELISA for the diagnosis of tropical theileriosis

The recombinant surface protein of Theileria annulata (TaSP) was used in the standardization and validation of an enzyme linked immunosorbent assay (ELISA) for the detection of circulating antibodies against tropical theileriosis. ELISA data were expressed as the percentage positivity (PP) of the reactivity of an internal positive control. A total of 50 sera samples from a disease-free area were used for the calculation of the cut-off value which served as a threshold between the positive and the negative sera samples. This was determined as the mean PP plus two standard deviations or the twice the mean PP of the results obtained with these negative samples. The obtained thresholds were 17.8% and 18.3%, respectively. Accordingly, the reactivity of 140 field sera samples collected at random from an area known to be endemic for tropical theileriosis in Sudan was determined as PP values which were then compared to the results obtained using the indirect fluorescence antibody test (IFAT) from the same samples. Both tests showed a high degree of correlation. The TaSP-ELISA had a sensitivity of 99.1% and specificity of 90.47% when taking the IFAT as a reference test. Our test has proved its suitability for the diagnosis of tropical theileriosis and could be used in serological surveys to map out the prevalence of the disease or to monitor vaccination efficiencies in disease-free populations.

Characterization of a polymorphic gene of T. lestoquardi and of a recently identified Theileria species pathogenic for small ruminants in China

In the present study, we identified a gene from Theileria lestoquardi and from a recently described Theileria species which is highly pathogenic for small ruminants in China. Since the taxonomic position of the latter parasite is still not clear, we refer to it as Theileria (China) species. The gene described here comprises an open reading frame of about 948 bp which prospectively encodes a 35-kDa protein. Its sequence is most closely related to the polymorphic immunodominant membrane protein of T. parva (36% identity). A search for sequence patterns and motifs within the predicted amino acid sequence revealed that this gene possesses three membrane-spanning regions at its C-terminal part, suggesting that it is a membrane protein. Several allelic variants of this gene were found in each parasite species, demonstrating interspecies and intraspecies variation. The predicted amino acid sequence variants display a substantial size and sequence polymorphism in the central part of its presumed extracellular region, while the N-terminal and the transmembrane/intracellular regions are highly conserved.