Think regionally, act locally: metals in honeybee workers in the Netherlands (surveillance study 2008).

In June 2008, a surveillance study for metals in honeybees was performed in the Netherlands. Randomly, 150 apiaries were selected. In each apiary, five colonies were sampled. Per apiary, the hive samples were pooled. The apiary sample was analysed for Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Sb, Se, Sn, Sr, Ti, V and Zn. All metals could be detected in all apiaries. As, Li, Sb, Sn and V were detected in part of the apiaries. The overall picture showed a regional pattern. In apiaries in the east of the Netherlands, Al, Ba, Cr, Mn, Mo, Ni, Se and Ti are found in higher concentrations compared to the west. In-region variation was demonstrated, indicating local effects. The vicinity of the apiaries was mapped afterwards and characterised as land uses of >50 % agricultural area, >50 % wooded area, >50 % urban area and mixed land use within a circle of 28 km(2) around the apiary. The results indicated that in apiaries located in >50 % wooded areas, significantly higher concentrations of Al, Ba, Cd, Cr, Cu, Li, Mn, Mo, Ni, Sb, Sr, Ti and Zn were found compared to agricultural, urban and mixed land use areas. We conclude that (1) the ratio between metal concentrations varies per region, demonstrating spatial differences, and (2) there is in-region local variation per metal. The results indicate the impact of land use on metal concentrations in honeybees. For qualitative bioindication studies, regional, local and land use effects should be taken into account.

Transport Spectroscopy of a Spin-Coherent Dot-Cavity System.

Quantum engineering requires controllable artificial systems with quantum coherence exceeding the device size and operation time. This can be achieved with geometrically confined low-dimensional electronic structures embedded within ultraclean materials, with prominent examples being artificial atoms (quantum dots) and quantum corrals (electronic cavities). Combining the two structures, we implement a mesoscopic coupled dot-cavity system in a high-mobility two-dimensional electron gas, and obtain an extended spin-singlet state in the regime of strong dot-cavity coupling. Engineering such extended quantum states presents a viable route for nonlocal spin coupling that is applicable for quantum information processing.

Antineuronal antibodies in patients with neurologic complications of primary Sjögren's syndrome.

Neurologic complications of both the central and peripheral nervous systems occur frequently in patients with primary Sjögren's syndrome (primary SS), but the underlying cause of these complications is unknown. We studied the presence of antineuronal antibodies in relation to neurologic complications in a consecutive series of 45 patients with primary SS. Twenty-five patients had neurologic complications: 12 patients with polyneuropathy, three with psychiatric disorders, four with carpal tunnel syndrome, seven with migraine, seven with myalgia, and four with other complications (transverse myelitis, stroke, Bell's palsy, and pyramidal signs). Ten patients had more than one neurologic complication. Eleven patients had major and 14 had minor complications according to criteria used for rating neurologic complications in patients with systemic lupus erythematosus. Antineuronal antibodies were present in six of 11 (55%) patients with major neurologic complications and in four of 34 (11%) of patients without major neurologic complications (p = 0.001). This difference could be attributed mainly to the group of patients with polyneuropathy. Three of the 10 sera of patients with positive antineuronal antibodies had antibodies reacting with a 38-kd neuronal protein on immunoblotting, identical to the anti-Hu antibody reactivity in paraneoplastic neurologic disease associated with small-cell lung cancer.

Use of IS901 and IS1245 in RFLP typing of Mycobacterium avium complex: relatedness among serovar reference strains, human and animal isolates.

SETTING: Mycobacterium avium complex (MAC) includes major acquired immune deficiency syndrome (AIDS)-associated pathogens. Formerly, MAC serotyping was used for epidemiological purposes. Recently, restriction fragment length polymorphism (RFLP) typing has become available. OBJECTIVE: Examination of the usefulness of insertion sequence IS1245 in RFLP typing of MAC isolates and the association with IS901 RFLP. DESIGN: Ninety-four serovar reference strains were compared with 144 clinical and animal MAC isolates in RFLP typing. RESULTS: All but four strains containing M. avium-specific-rRNA possessed IS1245. Most human isolates showed polymorphic multiband IS1245 patterns, which were associated with serovars 4, 6 and 8. Sequential clinical isolates obtained at up to five years' distance displayed indistinguishable/closely related patterns. Eleven M. paratuberculosis isolates showed indistinguishable six-band patterns. All 29 MAC isolates from 23 bird species, 7/23 from mammals and 1/81 clinical isolates showed an IS1245 three-band pattern, associated with serovars 1, 2 and 3. All these IS1245 'bird' type strains showed closely related IS901 RFLPs. Only three IS1245 'non-bird' type strains contained IS901, but exhibited completely different RFLP patterns. CONCLUSION: IS1245-RFLP typing is useful for the classification of M. avium and epidemiology of most human isolates. The highly conserved IS901 and IS1245 RFLPs among 'bird' type isolates provide proof that these strains constitute a separate taxon within the MAC.

Investigation of cross contamination in a Mycobacterium tuberculosis laboratory using IS6110 DNA fingerprinting.

SETTING: A laboratory for routine culturing of Mycobacterium tuberculosis. OBJECTIVE: Investigation of an episode of laboratory cross contamination using IS6110 restriction fragment length polymorphism (RFLP) typing. Improvement of laboratory protocols to prevent contaminations in the future. To stress the importance of 'good laboratory practice', and interaction with clinicians about laboratory results. DESIGN: Fingerprinting of mycobacterial isolates from 1) cultures suspected of being contaminated and 2) strains suspected of being the source of the cross-contamination. RESULTS: RFLP typing results indicated that clinical samples were contaminated by strains which had been processed in species identification procedures one day earlier in the same safety cabinet. This cross contamination also resulted in exceptional RFLP typing results--mixed banding patterns. Three patients were treated on the basis of false-positive laboratory results. Because the laboratory results were confusing for the clinicians, the treatment of one true tuberculosis patient was severely delayed. CONCLUSION: 'Good laboratory practice' is very important to prevent cross contamination. RFLP typing proved to be a useful tool to trace the source of contamination. Interaction with clinicians receiving doubtful results is of the utmost importance.

Changes in levels of hepatic biotransformation enzymes and haemoglobin levels in female plaice (Pleuronectes platessa) after oral administration of a technical polychlorinated biphenyl mixture (Clophen A40).

Female plaice (Pleuronectes platessa) were orally dosed with a gelatin capsule containing a solution of the technical PCB mixture Clophen A40 in sunflower oil. They were compared to plaice injected with a gelatin capsule containing only the sunflower oil at 10 and 16 days after injection. Even at 16 days after injection, the increase in concentrations of individual CB congeners in muscle was proportional to their contribution in Clophen A40. Biochemical effects are related to increases in concentrations of well-separable CB congeners in muscle, which increased by factors between 1.6 and 64 compared to the reference group of fish. Of both sampling points, total cytochrome P-450 levels were higher than the control groups, but surprisingly ethoxyresorufin-O-deethylase (EROD) activities did not differ between the groups. Enzyme-linked immunosorbent assay (ELISA) showed increased concentrations of the inducible cytochrome P-450IA1 in PCB-treated fish. The apparent lack of EROD induction may be due to competitive substrate inhibition by certain CB congeners present in the sample. The activity of glutathione-S-transferase (GST) (with CDNB as model substrate) was significantly elevated by PCB-treatment at day 16, but not at day 10. A longer time interval between injection with PCBs and induction of GST compared to P-450 monooxygenase activities has been reported earlier and may indicate that in fish both groups of enzymes are regulated individually and not as an [Arylhydrocarbon] gene battery as appears to be the case in mammals. Haemoglobin concentrations and MCHC were decreased in fish treated with Clophen A40. Haematocrit values did not differ between groups of fish.

High frequency recombination between homologous baculoviruses in cell culture.

The frequency of recombination between homologous baculoviruses was investigated in cell culture upon coinfection with two Autographa californica nucleopolyhedrovirus (AcMNPV) recombinants. These parental recombinants differed at two loci, separated by 20 kb, each carrying a different marker. The progeny recombinants generated by homologous recombination were easily distinguishable by the presence or absence of these markers. The mean percentage of the newly generated recombinants relative to a single locus varied between 23 and 41%, depending on the multiplicity of infection used for coinfection. These results provide further evidence that homologous recombination occurring during baculovirus replication is a highly frequent event.

Host-mediated modification of PvuII restriction in Mycobacterium tuberculosis.

Restriction endonuclease PvuII plays a central role in restriction fragment length polymorphism analysis of Mycobacterium tuberculosis complex isolates with IS6110 as a genetic marker. We have investigated the basis for an apparent dichotomy in PvuII restriction fragment pattersn observed among strains of the M. tuberculosis complex. The chromosomal regions of two modified PvuII restriction sites, located upstream of the katG gene and downstream of an IS1081 insertion sequence, were studied in more detail. An identical 10-bp DNA sequence (CAGCTGGAGC) containing a PvuII site was found in both regions, and site-directed mutagenesis analysis revealed that this sequence was a target for modification. Strain-specific modification of PvuII sites was identified in DNA from over 80% of the nearly 800 isolates examined. Furthermore, the proportion of modifying and nonmodifying strains differs significantly from country to country.