Induction of micronuclei in haemocytes and gill cells of zebra mussels, Dreissena polymorpha, exposed to clastogens

Zebra mussels, Dreissena polymorpha, were exposed to four directly acting reference clastogens (mitomycin C, bleomycin, dimethylarsinic acid and potassium chromate) under laboratory conditions. The aim was to examine the inducibility of micronuclei (MN) in haemocytes and gill cells. Positive responses were observed in both tissues for all four substances used under the given test conditions. The mean MN frequencies in treated mussels ranged between 3.2 and 6.9/1000 in haemocytes and between 5.4 and 6.7/1000 in gill cells. The spontaneous MN levels averaged 1.2 and 2.8/1000 in haemocytes and gill cells, respectively. The MN induction capacity of the different chemicals was equivalent in both tissues, except for the treatment with dimethylarsinic acid which generated a significantly higher MN rate in gill cells than in haemocytes. Several characteristics suggest that haemolymph is the more appropriate test tissue for environmental genotoxicity assessment: (1) a shorter preparation time of slides, (2) a more accurate identification of unambiguous MN, (3) a lower baseline MN frequency and a higher induction factor.

Multiplexed lipid dip-pen nanolithography on subcellular scales for the templating of functional proteins and cell culture

Molecular patterning processes taking place in biological systems are challenging to study in vivo because of their dynamic behavior, subcellular size, and high degree of complexity. In vitro patterning of biomolecules using nanolithography allows simplification of the processes and detailed study of the dynamic interactions. Parallel dip-pen nanolithography (DPN) is uniquely capable of integrating functional biomolecules on subcellular length scales due to its constructive nature, high resolution, and high throughput. Phospholipids are particularly well suited as inks for DPN since a variety of different functional lipids can be readily patterned in parallel. Here DPN is used to spatially pattern multicomponent micro- and nanostructured supported lipid membranes and multilayers that are fluid and contain various amounts of biotin and/or nitrilotriacetic acid functional groups. The patterns are characterized by fluorescence microscopy and photoemission electron microscopy. Selective adsorption of functionalized or recombinant proteins based on streptavidin or histidine-tag coupling enables the semisynthetic fabrication of model peripheral membrane bound proteins. The biomimetic membrane patterns formed in this way are then used as substrates for cell culture, as demonstrated by the selective adhesion and activation of T-cells.

The role of sincalide cholescintigraphy in the evaluation of patients with acalculus gallbladder disease

Thirty-six patients with biliary colic and normal oral cholecystograms, upper gastrointestinal tract roentgenograms, and results of gallbladder ultrasonography underwent sincalide-stimulated biliary excretion scanning. Nineteen of these patients subsequently underwent cholecystectomies. Gallbladder ejection fractions (EFs) ranged from 0% to 88% (mean, 38%) and nine of 19 patients had exact pain reproduction with sincalide. All patients except one (EF, 35%) were cured of their symptoms. However, five patients were also cured who had a normal EF (greater than 50%). Histologically, 11 gallbladders showed chronic cholecystitis and eight were normal. We conclude that the sincalide biliary excretion scan is a useful test to study this group of patients. In patients with a decreased EF, cholecystectomy can be recommended with a high probability of symptom relief. In patients with normal EFs, clinical judgment is required, as some of these patients (five of five in this series) may still benefit from operation.

Buried interfacial layer of highly oriented molecules in copper phthalocyanine thin films on polycrystalline gold

The growth of copper phthalocyanine thin films evaporated on polycrystalline gold is examined in detail using near edge x-ray absorption fine structure spectroscopy and surface sensitive x-ray photoemission spectroscopy. The combination of both methods allows distinguishing between the uppermost layers and buried interface layers in films up to approximately 3 nm thickness. An interfacial layer of approximately 3 ML of molecules with an orientation parallel to the substrate surface was found, whereas the subsequent molecules are perpendicular to the metal surface. It was shown that even if the preferred molecular orientation in thin films is perpendicular, the buried interfacial layer can be oriented differently.

A review of myrmecophily in ant nest beetles (Coleoptera: Carabidae: Paussinae): linking early observations with recent findings

Myrmecophily provides various examples of how social structures can be overcome to exploit vast and well-protected resources. Ant nest beetles (Paussinae) are particularly well suited for ecological and evolutionary considerations in the context of association with ants because life habits within the subfamily range from free-living and predatory in basal taxa to obligatory myrmecophily in derived Paussini. Adult Paussini are accepted in the ant society, although parasitising the colony by preying on ant brood. Host species mainly belong to the ant families Myrmicinae and Formicinae, but at least several paussine genera are not host-specific. Morphological adaptations, such as special glands and associated tufts of hair (trichomes), characterise Paussini as typical myrmecophiles and lead to two different strategical types of body shape: while certain Paussini rely on the protective type with less exposed extremities, other genera access ant colonies using glandular secretions and trichomes (symphile type). We compare these adaptations with other taxonomic groups of insects by joining contemporary research and early sources and discuss the possibility of an attracting or appeasing effect of the secretion. Species that are ignored by their host ants might use chemical mimicry instead. Furthermore, vibrational signals may contribute to ant-beetle communication, and chemical signals have proven to play a role in host finding. The powerful defense chemistry of paussines as "bombardier beetles" is not used in contact with host ants. We attempt to trace the evolution of myrmecophily in paussines by reviewing important aspects of the association between paussine beetles and ants, i.e. morphological and potential chemical adaptations, life cycle, host specificity, alimentation, parasitism and sound production.

Flexible fibreoptic bronchoscopy via the laryngeal mask

The efficacy of flexible fibreoptic bronchoscopy through the laryngeal mask was investigated in 20 patients under total intravenous anaesthesia with propofol, fentanyl, atropine and suxamethonium. Mask size 4 was used for men and size 3 for women. Ventilation was performed with oxygen in air, FIO2 0.6. The ventilatory pressures were median 18 (9-40) cmH2O (1.8 (0.9-3.9) kPa) before the bronchoscope was inserted. When the tip of the bronchoscope was above the vocal cords the ventilatory pressures increased to 22 (10-43) mmHg (2.2 (1.0-4.2) kPa) (P < 0.001), and when the tip was situated at the mid-tracheal level there was a further increase to 24 (12-50) mmHg (2.4 (1.2-4.9) kPa) (P < 0.001). Maximal gas leakages were median 1 (0-2) l/min-1. PEEP at the mid-tracheal level was 3 (0-7) cmH2O (0.3(0-0.7) kPa). When 15 min of the procedure had elapsed, PaO2 was 232 (112-350) mmHg (30.9 (14.9-46.6) kPa) and PaCO2 39 (33-46) mmHg (5.2(4.4-6.1) kPa). The lowest oxygen saturation was median 98 (96-100)% and the highest end-tidal CO2 34 (24-41) mmHg (4.5(3.2-5.5) kPa). It was easy to examine the laryngeal opening and a good assessment of vocal cord function was allowed when muscle relaxation ceased. We conclude that flexible fibreoptic bronchoscopy through the laryngeal mask is a safe technique provided that total intravenous anaesthesia is used. It is a valuable alternative to flexible bronchoscopy performed with topical anaesthesia.

Magnetic proximity effect in YBa2Cu3O7/La(2/3)Ca(1/3)MnO3 and YBa2Cu3O7/LaMnO(3+δ) superlattices

Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa2Cu3O7 and ferromagnetic-metallic La0.67Ca0.33MnO3 or ferromagnetic-insulating LaMnO(3+δ). We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La0.67Ca0.33MnO3 and almost absent for ferromagnetic-insulating LaMnO(3+δ). We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature.

Forests as promoters of terrestrial life-history strategies in East African amphibians

Many amphibian lineages show terrestrialization of their reproductive strategy and breeding is partially or completely independent of water. A number of causal factors have been proposed for the evolution of terrestrialized breeding. While predation has received repeated attention as a potential factor, the influence of other factors such as habitat has never been tested using appropriate data or methods. Using a dataset that comprises 180 amphibian species from various East African habitats, we tested whether species occurring in different habitats show different patterns of terrestrialization in their breeding strategy. We recovered a significant association between terrestrialized breeding strategies and forest habitats. In general, forest seems to act as a facilitator, providing a permissive environment for the evolution of terrestrialized breeding strategies. However, while terrestrial oviposition is strongly correlated with lowland and montane forest habitat, complete terrestrial development is significantly correlated with montane forest only, indicating different selective pressures acting at different steps towards complete terrestrial development.

Unraveling the Degradation Process of LiNi0.8Co0.15Al0.05O2 Electrodes in Commercial Lithium Ion Batteries by Electronic Structure Investigations

The degradation of LiNi0.8Co0.15Al0.05O2 (LNCAO) is reflected by the electrochemical performance in the fatigued state and correlated with the redox behavior of these cathodes. The detailed electrochemical performance of these samples is investigated by galvanostatic and voltammetric cycling as well as with the galvanostatic intermittent titration technique (GITT). Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to investigate the oxidation state of all three materials at the Ni L2,3, O K, and Co L2,3 edges at five different states of charge. Surface and more bulklike properties are distinguished by total electron yield (TEY) and fluorescence yield (FY) measurements. The electrochemical investigations revealed that the changes in the cell performance of the differently aged materials can be explained by considering the reaction kinetics of the intercalation/deintercalation process. The failure of the redox process of oxygen and nickel at low voltages leads to a significant decrease of the reaction rates in the fatigued cathodes. The accompanied cyclic voltammogram (CV) peaks appear as two peaks because of the local minimum of the reaction rate, although it is one peak in the CV of the calendarically aged LNCAO. The absence of the oxidation/reduction process at low voltages can be traced back to changes in the surface morphology (formation of a NiO-like structure). Further consequences of these material changes are overpotentials, which lead to capacity losses of up to 30% (cycled with a C/3 rate).

Scrotal swelling as the presenting symptom of acute perforated appendicitis in an infant

A ten-week-old patient with a known communicating hydrocele suddenly developed a tense, tender swelling of the scrotal half containing the hydrocele. Operated upon with the presumptive diagnosis of testicular torsion, pus was found in the hydrocele exuding from the abdominal cavity. At laparotomy a perforated appendix was discovered .

Back pain and health policy research: the what, why, how, who, and when

STUDY DESIGN

A background literature, supported by discussion and outcomes on the subject of Health Policy and Back Pain, from the Fifth International Forum on Low Back Pain Research in Primary Care, in Montreal in May 2002.

SUMMARY OF BACKGROUND DATA

A multitude of randomized controlled trials and systematic reviews have been completed in the field of back pain research. There has been limited health policy research in the field of back pain but a greater amount of health policy research in other medical fields.

METHODS

The focus of the workshop was on the contribution health policy could make in the area of back pain, the methodologies that are appropriate to research in back pain, and the barriers to back pain health policy research. The workshop was supported by the workshop coordinators' literature review.

RESULTS

There was consensus about the lack of improved outcomes from randomized controlled trials and individual treatments and general agreement on the importance supporting current research initiatives with health policy research. That policy-makers were developing policy in this area was agreed, and study methodology to support evidence based policy development was explored.

CONCLUSIONS

Health policy research is a relatively underdeveloped area of research in back pain. Back pain as a public health problem may be supported by a broader research approach and a collaborative association with policy-makers in this area.

Axonal transport of slow component a in sciatic nerves of hypo- and hyperthyroid rats

Axonal transport of slow component a was studied in dorsal root afferents of the sciatic nerves of hypo- and hyperthyroid rats. Three experimental groups of rats were made hypothyroid at the age of 12 weeks by the administration of 131I. From the age of 22 weeks to the end of the study, the groups were treated with daily subcutaneous injections of thyroxine in various doses to make them hypo-(0 microgram/100 g), normo- (1 microgram/100 g), and hyperthyroid (6 micrograms/100 g), respectively. The hypothyroid group had a moderate thyroid hormone deficiency (a serum triiodothyronine level of 0.19 +/- 0.10 nmol/L and a heart/body weight ratio of 1.87 +/- 0.09 g/kg at time of killing compared with 0.60 +/- 0.09 nmol/L and 2.18 +/- 0.06 g/kg, respectively, for the control group). The hyperthyroid group was severely deranged, with serum triiodothyronine being 3.30 +/- 0.37 nmol/L and a heart/body weight ratio of 3.11 +/- 0.16 g/kg. The hypothyroid rats showed a reduction in mean velocity for the transport of slow component a (0.80 +/- 0.07 mm/day compared with 0.91 +/- 0.05 mm/day in the controls). The width of the wave of activity was smaller for the hyperthyroid group than for the control group (6.6 +/- 0.7 mm compared with 8.1 +/- 1.2 mm), suggesting an increased clearance of the axonally transported activity in the proximal axon. A decrease in transport of slow component a in hypothyroidism may be the explanation of peripheral neuropathy with axonal degeneration occasionally seen in patients with severe myxoedema.

Electronic structure at transition metal phthalocyanine-transition metal oxide interfaces: Cobalt phthalocyanine on epitaxial MnO films

The electronic structure of the interface between cobalt phthalocyanine (CoPc) and epitaxially grown manganese oxide (MnO) thin films is studied by means of photoemission (PES) and X-ray absorption spectroscopy (XAS). Our results reveal a flat-lying adsorption geometry of the molecules on the oxide surface which allows a maximal interaction between the π-system and the substrate. A charge transfer from MnO, in particular, to the central metal atom of CoPc is observed by both PES and XAS. The change of the shape of N-K XAS spectra at the interface points, however, to the involvement of the Pc macrocycle in the charge transfer process. As a consequence of the charge transfer, energetic shifts of MnO related core levels were observed, which are discussed in terms of a Fermi level shift in the semiconducting MnO films due to interface charge redistribution.