The prevalence of Dichelobacter nodosus in clinically footrot-free sheep flocks: a comparative field study on elimination strategies

Background

Ovine footrot caused by Dichelobacter nodosus (D nodosus) is an infectious disease affecting sheep worldwide. Switzerland plans a nationwide footrot eradication program, based on PCR-testing of interdigital swab samples. The aim of this study was to test for the presence of D nodosus in clinically footrot-free sheep flocks which had been subjected to different treatment strategies, to assess whether they were feasible for the eradication process, especially focussing on antimicrobial flock treatments. Clinical scoring and PCR-results were compared. Ten farms had used hoof bathing and hoof trimming without causing bleeding, ten had used individual treatments and flock vaccines to gain the free status and ten had become free through whole-flock systemic macrolide treatment. For every farm, three risk-based collected pool samples were analysed for the occurrence of virulent and benign D nodosus by PCR detection of aprV2/aprB2.

Results

Six flocks from any treatment group tested positive for aprB2 in all pools. Clinical signs were absent at the time of sampling, but some flocks had experienced non-progressive interdigital inflammation previously. Two flocks tested aprV2-positive in the high-risk pool. One of them underwent a progressive footrot outbreak shortly after sampling. Individual retesting indicated, that virulent D nodosus most likely was reintroduced by a recently purchased ram. In the second flock, a ram was tested positive and treated before clinical signs occurred.

Conclusions

All treatment strategies eliminated the causative agent and were found to be suitable for implementation in the PCR-based eradication process. PCR-testing proved to be more sensitive than visual scoring, as it also detected clinically healthy carriers. It will be of benefit as a diagnostic tool in elimination and surveillance programs.

Infektiöse Lahmheiten beim Schaf – Therapie möglichkeiten in der tierärztlichen Praxis

Infektiöse Klauenerkrankungen des Schafes sind unter den Aspekten des Tierschutzes, der Diagnose und der Behandlung problematisch. Neben den Einzeltiererkrankungen und Lahmheiten im Zusammenhang mit Allgemeinerkrankungen stellen insbesondere die auf Herdenbasis auftretenden infektiösen Klauenerkrankungen wie die Moderhinke den behandelnden Tierarzt aus mehreren Gründen vor Probleme. In dem Artikel werden die verschiedenen Klauenerkrankungen kurz dargestellt und Hinweise zum Vorgehen bei der Therapie infektiöser Klauenkrankheiten des Schafes, zur Auswahl der Behandlungsmethode und zum Einsatz von Medikamenten gegeben. Die verschiedenen Behandlungsmaßnahmen wie Klauenschnitt, Klauenbäder, lokale und systemische antibiotische Therapie sowie die prophylaktische Impfung werden beschrieben und unter Berücksichtigung internationaler Forschungsergebnisse diskutiert. Bei der Auswahl der Medikamente zeigt sich, dass aufgrund fehlender Zulassungen in Deutschland der behandelnde Tierarzt beinahe regelmäßig gezwungen ist, Arzneimittel umzuwidmen. Die Problematik der medikamentösen Versorgung der kleinen Wiederkäuer als „minor species“ wird verdeutlicht und mit dem Aufruf an die involvierten Stellen verbunden, an einer Verbesserung dieser für alle Seiten unbefriedigenden Situation mitzuarbeiten.

Empfehlung für die Haltung von Schafen und Ziegen der Deutschen Gesellschaft für die Krankheiten der kleinen Wiederkäuer, Fachgruppe der DVG

Es werden Empfehlungen für die verschiedenen Haltungsformen auf der Basis der gesetzlichen Rahmenbedingungen für die Haltung von Schafen und Ziegen zusammengefasst. Berücksichtigung finden dabei die Wanderschäferei, die Hüte- und Koppelschafhaltung sowie die Alpung. Intensiv wird auf die Belange der Weidehaltung, der Stallhaltung, der Versorgung mit Futter und Wasser, der Geburt, der Lämmeraufzucht und der Gesundheitsvorsorge eingegangen. Dabei werden die Rahmenbedingungen sowohl für die extensive als auch für die intensive Haltung und Nutzung von Schafen und Ziegen abgesteckt. Die speziesspezifischen Kompensationsmöglichkeiten, deren Grenzen und Anzeichen der Dekompensation werden exemplarisch aufgezeigt. Durch die Einhaltung dieser Empfehlungen sollen den in unserer Obhut gehaltenen Nutztieren die „fünf Freiheiten (13)” zuverlässig gewährt werden: 1. Freisein von Hunger und Durst, 2. Freisein von Unbehagen, 3. Freisein von Schmerz, Verletzungen und Krankheiten, 4. Freisein zum Ausleben normaler Verhaltensweisen und 5. Freisein von Angst und Leiden.

Quantum-Enhanced Sensing Based on Time Reversal of Nonlinear Dynamics

We experimentally demonstrate a nonlinear detection scheme exploiting time-reversal dynamics that disentangles continuous variable entangled states for feasible readout. Spin-exchange dynamics of Bose-Einstein condensates is used as the nonlinear mechanism which not only generates entangled states but can also be time reversed by controlled phase imprinting. For demonstration of a quantum-enhanced measurement we construct an active atom SU(1,1) interferometer, where entangled state preparation and nonlinear readout both consist of parametric amplification. This scheme is capable of exhausting the quantum resource by detecting solely mean atom numbers. Controlled nonlinear transformations widen the spectrum of useful entangled states for applied quantum technologies.

Observation of Scaling in the Dynamics of a Strongly Quenched Quantum Gas

We report on the experimental observation of scaling in the time evolution following a sudden quench into the vicinity of a quantum critical point. The experimental system, a two-component Bose gas with coherent exchange between the constituents, allows for the necessary high level of control of parameters as well as the access to time-resolved spatial correlation functions. The theoretical analysis reveals that when quenching the system close to the critical point, the energy introduced by the quench leads to a short-time evolution exhibiting crossover reminiscent of the finite-temperature critical properties in the system's universality class. Observing the time evolution after a quench represents a paradigm shift in accessing and probing experimentally universal properties close to a quantum critical point and allows in a new way benchmarking of quantum many-body theory with experiments.

[Water requirements, water supply and thermoregulation in small ruminants in pasture-based husbandry systems]

Water is an essential source of life and is available to animals as free water, water content of feed, film water (e. g. dew) and metabolic water. The water requirements of small ruminants are influenced by the type of feed, climate, stage of production, type and length of the fleece or hair coat, husbandry factors and the general health of the animal. Differences in water metabolism, drinking behaviour and the efficiency of temperature regulation are further influenced by species, breed, production type, husbandry system, acclimatisation and adaptation. Small ruminants have been, and are still predominantly kept in extensive husbandry systems. They are therefore genetically and phenotypically well adapted to these conditions and possess a range of physiological and behavioural mechanisms to deal with adverse and suboptimal weather conditions. Regarding animal welfare, there is considerable debate in the discussion and assessment of what constitutes a sufficient water supply for small ruminants under different husbandry conditions, often involving differences between theoretical demands and practical experience. This publication reviews and summarises the current literature regarding water requirements, water metabolism and thermoregulatory mechanisms of small ruminants to provide the basis for an informed assessment of extensive husbandry systems in terms of compliance with animal-welfare requirements.

Scalable spin squeezing for quantum-enhanced magnetometry with Bose-Einstein condensates

A major challenge in quantum metrology is the generation of entangled states with a macroscopic atom number. Here, we demonstrate experimentally that atomic squeezing generated via nonlinear dynamics in Bose-Einstein condensates, combined with suitable trap geometries, allows scaling to large ensemble sizes. We achieve a suppression of fluctuations by 5.3(5) dB for 12,300 particles, from which we infer that similar squeezing can be obtained for more than 10(7)  atoms. With this resource, we demonstrate quantum-enhanced magnetometry by swapping the squeezed state to magnetically sensitive hyperfine levels that have negligible nonlinearity. We find a quantum-enhanced single-shot sensitivity of 310(47) pT for static magnetic fields in a probe volume as small as 90  μm3.

Der Einfluss von Klauenerkrankungen auf das Tierwohl von Schaf und Ziege

Mit der Publikation der „Empfehlung für die Haltung von Schafen und Ziegen“ durch die Fachgruppe Krankheiten der kleinen Wiederkäuer der Deutschen Veterinärmedizinischen Gesellschaft wurden Schafhaltern, praktizierenden Tierärzten und Kontrollbehörden Leitlinien an die Hand gegeben, die auch für die Beurteilung des Tierwohls dienen. Um die Anwendung dieser Leitlinien in der Praxis zu erleichtern, werden in Ergänzung dazu die im Zusammenhang mit Lahmheiten bei Schaf und Ziege getroffenen Aussagen anhand der verfügbaren Literaturquellen diskutiert und anhand praktischer Beispiele kommentiert. Diagnostische Werkzeuge, Kriterien und Richtwerte werden ebenso wie entsprechende Maßnahmen und Zielvorgaben besprochen.

[Influence of lameness caused by hoof disease on welfare in sheep and goats. A comment on the guidelines of the German Small Ruminant Veterinary Association]

The publication of the "Recommendations of husbandry and welfare of sheep and goats" by the German Small Ruminant Veterinary Association provides guidelines that are also used for assessing animal welfare. The included statements concerning lameness are reviewed according to the available literature and commented on with the help of practical examples. Diagnostic tools, criteria, appropriate measures and target values are discussed to facilitate the application of the guidelines.

Accurate atom counting in mesoscopic ensembles

Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

Abstract P4-12-30: A bivalent Her2 targeting DARPin with high efficacy against Her2-low and Her2-positive tumors

The approval of Herceptin, Perjeta and Kadcyla has dramatically improved the outcome of the 15% of breast cancer patients with high expression of Her2 (Her2-positive, IHC3+). In contrast, up to 50% of women with breast cancer express low levels of Her2 (Her2-low, IHC+2 or +1) at diagnosis, and these patients do not derive benefit from approved Her2 targeted therapies. It is estimated that 5-10% of Her2-positive patients will also develop Her2-low metastases refractory to treatment. Therefore, new therapeutic strategies are needed to alleviate the high tumor burden of Her2-low patients.

We generated a bivalent Designed Ankyrin Repeat Protein (DARPin) containing two anti-Her2 moieties that target unique non-overlapping epitopes on Her2 (biparatopic). The biparatopic DARPin exerts a strong pro-apoptotic response on a panel of breast and gastric cancer cell lines, which cannot be fully recapitulated by treatment with Herceptin, Perjeta or both combined. DARPin treatment of Her2-positive breast cancer BT474 cells induces apoptosis (IC50 < 1nM) in virtually all cells within 24 hours, whereas single or combined treatment with Herceptin and/or Perjeta reduces proliferation by 50% (IC50 = 2-4nM). The biparatopic DARPin inhibits as well the viability (via apoptosis) of Her2-low MDAMB175 cells with a 100-fold higher potency than Herceptin. Mechanistically, treatment with the anti-Her2 biparatopic DARPin inhibits both Her2 and Her3 signaling, which in turn results in the induction of apoptosis. Interestingly, cell treatment with the mix of the two individual anti-Her2 DARPin moieties does not recapitulate the apoptotic effect of the biparatopic molecule, indicating that both moieties must be linked for maximum efficacy. In vivo, the biparatopic DARPin shows efficient anti-tumor activity in established breast cancer Her2-positive xenografts and Her2-low PDX tumor models. DARPin treatment of Her2-positive BT474 xenograft in BALB/c mice results in rapid tumor regression (50% tumor shrinkage after one dose) that is sustained at least during one month after the last dose. The biparatopic DARPin strongly inhibits tumor growth as well in a Her2-low breast cancer PDX in NMRI mice, where it demonstrates superior efficacy compared to Herceptin (DARPin/Herceptin tumor volume ratio < 30%).

In summary, biparatopic targeting of Her2 enables inhibition of both Her2 and Her3, and blocks a tumor driver and its resistance mechanism. As a result, the DARPin interferes with both the proliferation and survival of tumor cells and triggers durable anti-tumor responses in vivo. DARPin treatment of Her2 positive tumors in mice show equivalent efficacy to Herceptin with faster kinetics; an effect that is magnified in Her2-low PDX tumors where the DARPin provides superior tumor control to Herceptin. Altogether, our data demonstrate the potential for the biparatopic DARPin to surpass some of the limitations of approved Her2 targeted agents, and warrants clinical investigation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-30.

[Recommendations for the husbandry and welfare of sheep and goats by the German Small Ruminant Veterinary Association. Part 1]

Recommendations for the different forms of sheep and goat husbandry based on the legal regulations are summarized. These are given in particular respect to transhumance, tending, alpine farming, and indoor housing. The requirements for pasture, housing, supply of water and food, lambing, rearing of lambs, and health management are intensively discussed. The general requirements of the extensive as well as of the intensive husbandry of sheep and goats are defined. Examples of species-specific capabilities for adaption, the limits of adaption, and signs of decompensation are provided. Compliance with these recommendations should accord the animals entrusted to our care the "five freedoms (13)": 1. Freedom from hunger and thirst, 2. freedom from discomfort, 3. freedom from pain, injury, or disease, 4. freedom to express normal behaviour, and 5. freedom from fear and distress.

Empfehlung für die Haltung von Schafen und Ziegen der Deutschen Gesellschaft für die Krankheiten der kleinen Wiederkäuer, Fachgruppe der DVG

Der zweite Teil der Haltungsempfehlungen beschäftigt sich mit der Gesundheitsvorsorge sowie den gesetzlichen Rahmenbedingungen für die Haltung von Schafen und Ziegen, den Transport und die Eingriffe an Schafen und Ziegen. Das vorgeschlagene Konzept der Gesundheitsvorsorge zielt auf die Entwicklung eines für jede Herde individuellen Gesundheitsplans ab, in dem neben der Abwehr von anzeige- und meldepflichtigen Krankheiten gerade auch die chronischen, sich langsam entwickelnden Erkrankungen und ein regelmäßiges Parasitenmonitoring Berücksichtigung finden. Dabei liegt der Schwerpunkt auf dem frühen Erkennen und der Prophylaxe von Erkrankungen. In diesem Zusammenhang wird auf den Umgang mit Lahmheiten, die Schur, Tierzukauf und Quarantäne sowie die Reinigung und Desinfektion in Schaf- und Ziegenherden intensiver eingegangen. Zum Transport von Tieren und zu Eingriffen bei Tieren liegen mit der Tierschutztransportverordnung und entsprechenden europäischen Regelungen detaillierte Vorschriften zu diesen Komplexen vor. Die gesetzlichen Bestimmungen und die praktische Durchführung werden übersichtlich dargestellt.

[Recommendations for the husbandry and welfare of sheep and goats by the German Small Ruminant Veterinary Association. Part 2]

The second part of the recommendations deals with the healthcare and the regulatory framework for the husbandry of sheep and goats. The suggested concept for healthcare aims to develop an individual health plan for every flock. This health plan focuses not only on the prevention of notifiable diseases, but also on chronic and slow infections as well as on parasite monitoring. The emphasis is on early detection of diseases and prophylaxis. In conjunction with this, the handling of lameness, shearing, animal trade and quarantine as well as cleaning and disinfection in sheep and goat flocks are intensively discussed. There are detailed federal and European legal regulations concerning the transport and the physical well-being of animals. These laws are clearly presented and advice for their practical implementation is provided.

[Infectious causes of lameness in sheep - treatment options in veterinary practice]

Lameness in sheep induced by infectious agents can cause problems regarding animal welfare, diagnosis and treatment. Individual lame animals and lameness caused by systemic disease, but especially flock problems due to infectious causes of lameness, such as foot rot, can for various reasons pose a problem for veterinary treatment. The causes of lameness in sheep are described with a special focus on infectious flock problems, and the different treatment options such as foot trimming, foot baths and local and systemic antibiotic therapy as well as vaccination are discussed based on a review of recent international research. The limited choice of drugs licensed for use in sheep in Germany is highlighted. Treatment, therefore, often requires off-label use or the import of footbathing agents licensed in other European countries. The legal consequences of this lack of nationally licensed veterinary products in dealing with a "minor species" are discussed, with a final call for political solutions that will help improve this unsatisfactory situation.

Rabi flopping induces spatial demixing dynamics

We experimentally investigate the mixing and demixing dynamics of Bose-Einstein condensates in the presence of a linear coupling between two internal states. The observed amplitude reduction of the Rabi oscillations can be understood as a result of demixing dynamics of dressed states as experimentally confirmed by reconstructing the spatial profile of dressed state amplitudes. The observations are in quantitative agreement with numerical integration of coupled Gross-Pitaevskii equations without free parameters, which also reveals the criticality of the dynamics on the symmetry of the system. Our observations demonstrate new possibilities for changing effective atomic interactions and studying critical phenomena.

Lavasept® als Alternative für PVP-Iod zur präoperativen Antiseptik in der Ophthalmochirurgie

BACKGROUND

To reduce the risk of endophthalmitis PVP-iodine is typically used preoperatively. Since iodine is contraindicated in patients with a specific allergic history or severe thyroid disorder we studied the effect of Lavasept, which contains Polyhexanid as an antiseptic alternative.

PATIENTS AND METHODS

In a randomized controlled double-blind trial 3 drops of 0.2% Lavasept, 1.25% PVP-iodine or Ringer's solution were applied preoperatively to 67 patients, which have had a minimum of 5 colony forming units (cfu's) in the conjunctival swap. The effectiveness and tolerability were measured.

RESULTS

After application of Lavasept or PVP-iodine, the number of cfu was statistically significantly reduced. Lavasept reduced the number of bacterial colonies significantly better than PVP-iodine (p=0.05). All test solutions were equally well tolerated.

CONCLUSION

The use af Lavasept is safe, well tolerated and reduces the microbiological contamination of the conjunctival fornix effectively. lt provides a more effective reduction of the cfu's than PVP-iodine 1.25% and this effect tends to be prolonged. Lavasept is a good alternative option in ophthalmology for preoperative antisepsis.

Polyhexamethylbiguanid (PHMB) zur pr�operativen Antisepsis bei Kataraktoperation

BACKGROUND

We examined the efficacy and tolerability of Lavasept (polyhexamethylenbiguanid or PHMB)-an iodine-free antiseptic-in comparison to polyvinylpyrolidon iodine and Ringer's solution, as an alternative preoperative antiseptic.

PATIENTS AND METHODS

In a randomized controlled double-blind trial 3 drops of Lavasept, 1.25%, PVP-iodine or Ringer's solution were applied preoperatively in 29 patients. The number of colony forming units (cfu) grown from conjunctival smears and conjunctival hyperaemia, corneal epitheliopathy and ocular surface pain were assessed preoperatively, intraoperatively and 1 day postoperatively.

RESULTS

Despite intraoperative application of PVP-iodine, 40% of patients receiving Ringers solution still presented with more than 5 colony forming units (cfu) at the end of the procedure, while all patients that had additional preoperative Lavasept or PVP-iodine achieved relative sterility with less than 5 cfu (p < 0.05). While the effect of Lavasept lasted until the next day, conjunctival microbial colonisation recurred in eyes treated with PVP-iodine. As expected conjunctival hyperaemia and corneal epitheliopathy increased significantly postoperatively but no differences were observed between the 3 solutions tested.

CONCLUSION

The preoperative application of Lavasept reduces the conjunctival flora safely and effectively. The microbicidal efficacy is equal to PVP-iodine, but potentially longer lasting. No signs of local or systemic intolerability were observed. Lavasept may be used as a potential alternative preoperative antiseptic and is suitable for iodine-intolerant patients.

Synthesis and recognition by DNA polymerases of a reactive nucleoside for DNA diversification

The synthesis of 1-(2-deoxy-beta-D-erythro-pentofuranosyl)imidazole-4-hydrazide having the features of an ambigous base is reported. The recognition of the analogue by DNA polymerases as an incoming triphosphate as well as a template base was investigated. The mutagenic properties was evaluated by PCR. The potential of this new monomer for DNA diversification is illustrated by the reactivity of the nucleobase towards various aldehydes.

[Malaria surveillance in Germany 2000/2001--results and experience with a new reporting system]

In Germany, malaria is one of the most frequently imported infectious diseases. In January 2001, the newly implemented Infektionsschutzgesetz (Law for Protection Against Infectious Diseases) brought some important changes in surveillance case notification procedures. After one year, experience shows that the changes did not affect the continuity and representative nature of malaria reporting in Germany. In the years 2000 and 2001, 836 and 1,040 malaria cases, respectively, were reported. In both years, most of the patients were between 30 and 49 years old. 82 % of the infections had been acquired in Africa, and 11 % in Asia. The predominant parasite species was P. falciparum (70 %), followed by P. vivax (12 % in 2000, and 16 % in 2001, respectively). The majority of infections occurred among tourists, fewer in immigrants or business travellers. About two thirds of all patients had not taken any chemoprophylactics. Compared to previous years a decrease in the number of fatal cases was observed (1998: 21, 1999: 18, 2000: 8, 2001: 8). To ameliorate the situation of imported malaria intensified prevention activities are necessary, including efforts to improve choice and compliance of chemoprophylaxis and to facilitate timely diagnosis and treatment.

Structural basis for pterin antagonism in nitric-oxide synthase. Development of novel 4-oxo-pteridine antagonists of (6R)-5,6,7,8-tetrahydrobiopterin

Pathological nitric oxide (NO) generation in sepsis, inflammation, and stroke may be therapeutically controlled by inhibiting NO synthases (NOS). Here we targeted the (6R)-5,6,7,8-tetrahydro-l-biopterin (H(4)Bip)-binding site of NOS, which, upon cofactor binding, maximally increases enzyme activity and NO production from substrate l-arginine. The first generation of H(4)Bip-based NOS inhibitors employed a 4-amino pharmacophore of H(4)Bip analogous to antifolates such as methotrexate. We developed a novel series of 4-oxo-pteridine derivatives that were screened for inhibition against neuronal NOS (NOS-I) and a structure-activity relationship was determined. To understand the structural basis for pterin antagonism, selected derivatives were docked into the NOS pterin binding cavity. Using a reduced 4-oxo-pteridine scaffold, derivatives with certain modifications such as electron-rich aromatic phenyl or benzoyl groups at the 5- and 6-positions, were discovered to markedly inhibit NOS-I, possibly due to hydrophobic and electrostatic interactions with Phe(462) and Ser(104), respectively, within the pterin binding pocket. One of the most effective 4-oxo compounds and, for comparisons an active 4-amino derivative, were then co-crystallized with the endothelial NOS (NOS-III) oxygenase domain and this structure solved to confirm the hypothetical binding modes. Collectively, these findings suggest (i) that, unlike the antifolate principle, the 4-amino substituent is not essential for developing pterin-based NOS inhibitors and (ii), provide a steric and electrostatic basis for their rational design.

Rec (formerly Corf) function requires interaction with a complex, folded RNA structure within its responsive element rather than binding to a discrete specific binding site

It was recently reported that the human endogenous retrovirus HTDV/HERV-K encodes the regulatory protein Rec (formerly designated Corf), which is functionally equivalent to the nuclear export adapter proteins Rev of human immunodeficiency virus and Rex of human T-cell leukemia virus. We have demonstrated that the Rec protein interacts with a characteristic 429-nucleotide RNA element, the Rec-responsive element (RcRE), present in the 3' long terminal repeat of HTDV/HERV-K transcripts. In analogy to the Rev and Rex proteins, which have distinct RNA binding sites in their responsive elements, we have proposed that Rec may also have a defined binding site in the RcRE. In this report, we demonstrate that not every HTDV/HERV-K copy present in the human genome contains an active RcRE, and we characterize mutations that abrogate Rec function. In addition, we demonstrate that Rec function requires binding to a complex, folded RNA structure rather than binding to a discrete specific binding site, in contrast to Rev and Rex and their homologous responsive elements. We define four stem-loop structures in the RcRE that are essential for Rec function. Finally, we demonstrate that both Rev and Rex can mediate nuclear export through the RcRE but that their binding sites are different from each other and from that of Rec.

High-performance liquid chromatographic method with electrochemical detection for the analysis of O6-methylguanine

An improved system consisting of a combination of high-performance liquid chromatographic methods with electrochemical detection for the separation and analysis of the DNA adduct O6-methylguanine (O6MG) has been developed. This adduct is produced by the interaction of methylating agents with DNA and induces mispairing in the DNA of the target cells. A good separation of modified from unmodified bases is first achieved with an HPLC system using a Partisil 10 SCX column and a salt gradient. A second HPLC step with electrochemical detection and a C18 column is used for farther separation and quantitation of O6-methylguanine. This method shows a linear response up to 15 pg of 06MG tested. The lowest amount detected was 0.5 pg of O6MG and is highly reproducible. This method is useful to study DNA damage as a product of cellular metabolism and its effects on the process of carcinogenesis.

[Malaria incidence in Germany 1998/99--results of single case studies of the Robert Koch Institute]

Malaria is a common imported infectious disease in Germany. A total of 931 cases of malaria were reported in Germany in 1999 (1998: 1,008 cases). Most of the infected patients were 24-45 years of age. Eighty per cent of the cases acquired infection in Africa, in Asia (8.5%) and in Central and South America (5%). Plasmodium falciparum accounted for the largest number of cases (80%) followed by Plasmodium vivax (12%). In 1999 60% of all malaria cases were Germans. Most of them travelled for holidays or study purposes. 20 deaths, all attributed to falciparum malaria, were notified in 1999, most of them (19) were German citizens. In 1999 61% of the patients had not taken chemoprophylaxis at all while travelling abroad. Improving prophylactic measures is the only way to reduce the incidence of malaria cases in Germany.

Role of cytochrome P450 in DNA damage produced by treatment of colon cells with 1,2-dimethylhydrazine

Human colon cells (LS174T) were treated with the model colon carcinogen 1,2-dimethylhydrazine (DMH) to determine the production of O(6)-methylguanine DNA adducts. Three known P450 inducers (benzanthracene, pyrazole and phenobarbital) were used to produce different P450 environments in each group of cells prior to treatment with DMH. An increased level of DNA damage of different degrees above uninduced levels was observed in all treated groups. Inhibition of the natural protection systems (glutathione and O(6)-methyltransferase) were also included in the study. Glutathione apparently is not of significant protection against DMH damage in colon cells challenged with DMH. In contrast methyltransferase does exert a protective role in this type of cells by reducing the extent of DNA O(6)-methylguanine adduct formation in colon cells following induction of different panels of cytochrome P450 isoforms.

Release of nitric oxide from endothelial cells stimulated by YC-1, an activator of soluble guanylyl cyclase

1 In this study we examined the endothelium-dependent effect of YC-1 - a benzyl indazole derivative which directly activates soluble guanylyl cyclase (sGC) - on vascular relaxation and nitric oxide (NO) and guanosine-3',5'-cyclic monophosphate (cyclic GMP) in endothelial cells. 2 In preconstricted rat aortic rings with intact endothelium, YC-1 produced a concentration-dependent relaxation. However, the concentration response curve was shifted rightward to higher concentrations of YC-1, when (i) the aortas were pre-treated with L-NG-nitroarginine methylester (L-NAME) or (ii) the endothelium was removed. 3 Incubation of bovine aortic endothelial cells (BAEC) with YC-1 produced a concentration-dependent NO synthesis and release as assessed using a porphyrinic microsensor. Pre-incubating cells with L-NAME or with 8-bromo-cyclic GMP decreased this effect indicating that the YC-1 stimulation of NO synthesis is due to an activation of nitric oxide synthase, but not to an elevation of cyclic GMP. No direct effect of YC-1 on recombinant endothelial constitutive NO synthase activity was observed. 4 The YC-1 stimulated NO release was reduced by 90%, when extracellular free calcium was diminished. 5 In human umbilical vein endothelial cells (HUVEC), YC-1 stimulated intracellular cyclic GMP production in a concentration- and time-dependent manner. Stimulation of cyclic GMP was greater with a maximum concentration of YC-1 compared to calcium ionophore A23187. Similar effects were observed in BAEC and rat microvascular coronary endothelial cells (RMCEC). 6 When HUVEC and RMCEC were pre-treated with L-NG-nitroarginine (L-NOARG), the maximum YC-1 stimulated cyclic GMP increase was reduced by >/=50%. 7 These results indicate, that beside being a direct activator of sGC, YC-1 stimulates a NO-synthesis and release in endothelial cells which is independent of elevation of cyclic GMP but strictly dependent on extracellular calcium. The underlying mechanism needs to be determined further.

Inhibition of neuronal nitric oxide synthase by 4-amino pteridine derivatives: structure-activity relationship of antagonists of (6R)-5,6,7,8-tetrahydrobiopterin cofactor

The family of nitric oxide synthases (NOS) catalyzes the conversion of L-arginine to L-citrulline and nitric oxide (NO), an important cellular messenger molecule which has been implicated in the pathophysiology of septic shock and inflammatory and neurodegenerative disease states. NOS can be maximally activated by the ubiquitous cofactor, (6R)-5,6,7,8-tetrahydrobiopterin (H(4)Bip), and antagonists of H(4)Bip may be of therapeutic importance to inhibit pathologically high NO formation. The 4-amino substituted analogue of H(4)Bip was reported to be a potent NOS inhibitor. Therefore, we developed a series of novel 4-amino pteridine derivatives, anti-pterins, to pharmacologically target the neuronal isoform of nitric oxide synthase (NOS-I). To functionally characterize the pterin/anti-pterin interaction and establish a structure-activity relationship (SAR), we systematically altered the substituents in the 2-, 4-, 5-, 6-, and 7-position of the pteridine nucleus. Varying the substitution pattern in the 2-, 5-, and 7-position resulted in no significant inhibitory effect on enzyme activity. In contrast, bulky substituents in the 6-position, such as phenyl, markedly increased the inhibitory potency of the reduced 4-amino-5,6,7,8-tetrahydropteridines, possibly as a consequence of hydrophobic interactions within NOS-I. However, this was not the case for the aromatic 4-amino pteridines. Interestingly, chemical modification of the 4-amino substituent by dialkyl/diaralkylation together with 6-arylation of the aromatic 2,4-diamino pteridine resulted in potent and efficacious inhibitors of NOS-I, suggesting possible hydrophilic and hydrophobic interactions within NOS-I. This SAR agrees with (a) the recently published crystal structure of the oxygenase domain of the inducible NOS isoform (NOS-II) and (b) the comparative molecular field analysis of selected NOS-I inhibitors, which resulted in a 3D-QSAR model of the pterin binding site interactions. Further optimization should be possible when the full length structure of NOS-I becomes available.

Heterotrimerization of PII-like signalling proteins: implications for PII-mediated signal transduction systems

PII-like signalling molecules are trimeric proteins composed of 12-13 kDa polypeptides encoded by the glnB gene family. Heterologous expression of a cyanobacterial glnB gene in Escherichia coli leads to an inactivation of E. coli's own PII signalling system. In the present work, we show that this effect is caused by the formation of functionally inactive heterotrimers between the cyanobacterial glnB gene product and the E. coli PII paralogues GlnB and GlnK. This led to the discovery that GlnK and GlnB of E. coli also form heterotrimers with each other. The influence of the oligomerization partner on the function of the single subunit was studied using heterotrimerization with the Synechococcus PII protein. Uridylylation of GlnB and GlnK was less efficient but still possible within these heterotrimers. In contrast, the ability of GlnB-UMP to stimulate the adenylyl-removing activity of GlnE (glutamine synthetase adenylyltransferase/removase) was almost completely abolished, confirming that rapid deadenylylation of glutamine synthetase upon nitrogen stepdown requires functional homotrimeric GlnB protein. Remarkably, however, rapid adenylylation of glutamine synthetase upon exposing nitrogen-starved cells to ammonium was shown to occur in the absence of a functional GlnB/GlnK signalling system as efficiently as in its presence.

Identification of cytochrome P450s in human glioma cell line

Five different isoforms of cytochrome P450 including 1A1, 1A2, 2E1, 2A and 2B6 have been identified in human glioma Hs 683 cell line using RT-PCR reaction. These isoforms belong to four distinct subfamilies. The effect of benzanthracene (Ba) as inducer was tested on the mRNA level of cytochrome P450 1A1. Northern blot analysis clearly showed an induction response from these cells to Ba in a proportion that is comparable to the induction seen in rat glioma cells.

Effect of cytochrome P450 inducers on expression of oncogenes and a tumor suppressor gene in human colon cancer cells

To examine the possibility that chemical inducers of cytochrome P450 may have effects on the expression of oncogenes and a tumor suppressor gene, human colon LS174T cells were treated with different cytochrome P450 inducers such as benzanthracene (Ba), pyrazole (Pyr) and phenobarbital-hydrocortisone (Pb-Hc). Three forms of cytochrome P450 (CYP1A1, CYP1A2 and CYP2E1) were detected in the colon cell line and all of them were induced following chemical treatments. Altered expression of c-fos, c-myc, c-jun, was observed following the treatments. c-src, K-ras and p53 were not significantly affected by any of the treatments at the time-point selected. Interestingly, c-fos expression was the most dramatically altered by different treatments, showing repression with all of the treatments. These data show that some oncogenes are responsive to inducers of cytochrome P450, the enzyme system by which many carcinogens are activated.

Caloric restriction affects liver microsomal monooxygenases differentially in aging male rats

Caloric restriction (CR) extends life span and retards the onset of physiological changes and pathologies associated with aging, but the underlying mechanisms remain unresolved. This study demonstrates that CR postpones the documented age-related declines in and/or enhances the activity and microsomal concentration of several liver monooxygenases in male rats, i.e., NADPH cytochrome P-450 reductase, total cytochromes P-450. However, the relative concentration of cytochrome P-450b+C did not exhibit statistically significant changes, whereas another isozyme, the male specific P-450h, declined significantly in both ad libitum-fed and CR rats as a function of increasing age. While CR appears to retard age-associated changes in certain liver enzymes, this effect is by no means universal. The hepatic monooxygenases constitute a well-characterized enzyme system in which to examine the perturbation of the aging process by CR.

Purification and characterization of liver cytochrome P-446 isolated from protein energy malnourished rats

A liver cytochrome P-450 isozyme has been purified to homogeneity from protein-energy malnourished rats induced with beta-naphthoflavone (beta-NF). The purification steps included chromatography on DEAE-Sephadex-A-25, DEAE-cellulose (DE-53), hydroxylapatite (HA) and carboxymethyl-sephadex (CM) columns. The reduced carbon monoxide difference and absolute spectra showed a Soret peak at 446.5 nm. The wavelength maxima for the oxidized and reduced spectra were at 416 and 408 nm, respectively. Cytochrome P-446 appears to have a predominantly low spin ferric iron, migrates as a single band of molecular weight 56,000 in sodium dodecyl sulfate polyacrylamide gels and has a specific content of 14 nmol/mg of protein. P-446 oxidized various substrates at different rates in a reconstituted system with NADPH-cytochrome P-450 reductase and dilauroyl-phosphatidylcholine. In this system turnover rates for benzo[alpha]pyrene, testosterone and benzphetamine oxidation were: 81.10; 1.85 and 1.42 nmoles product/min/nmol P-446 respectively. While NH2 terminal amino acid sequence analysis of 18 of the first 20 residues suggests that the cytochrome P-446 isolated from malnourished rats is identical with form c, the catalytic activities suggest that this isozyme may be a more effective or efficient catalyst for some substrates.

Experimental chemotherapy with N'N'-bis(2-chloroethyl)-N-nitrosourea (BCNU) in autochthonous neurogenic tumors of the rat transplacentally induced by ethylnitrosourea

Autochthonous neurogenic tumors of the rat induced by transplacental application of ethylnitrosourea were used for the first time to study their suitability as tumor models for experimental chemotherapy. Of 189 transplacentally treated rats, 87% developed neurogenic tumors. After the initial clinical diagnosis of a neurogenic tumor, additional malignant tumors often occurred. The mean number of neurogenic tumors from 62 untreated control rats increased from 1.0 per rat at the time of randomization to 1.2 as revealed by autopsy and 1.5 tumors by histological examinations. Out of all neurogenic tumors, tumors of the brain were observed in 31%, tumors of cranial nerves in 36% (90% tumors of trigeminal nerve), tumors of spinal cord in 21%, and tumors of peripheral nerves in 10%. The median survival time until natural death of 62 control rats was 228 days. Rats with tumors of peripheral nerves lived shortest, followed by rats with tumors of cranial nerves, tumors of the spinal cord, and brain tumors. Brain tumors were mainly astrocytomas and oligodendrogliomas. The survival time of untreated rats from randomization to natural death was longest for those with brain tumors, followed by tumors of peripheral nerves, cranial nerves, and tumors of the spinal cord. There was great variation in survival time from a few days to more than 6 months. To study the responsiveness to chemotherapy, 62 rats received BCNU as a single intravenous dose of 9 and later 10 mg/kg. Sixty-two untreated control rats had a median survival time of 36 days (95% confidence interval 26-52 days), the treated rats 43.5 days (26-62 days). The difference was not statistically significant. BCNU produced a remission or a no change of neurologic symptoms in 60% (37 out of 62) in comparison to 39% (24 out of 62) in the control group (p less than 0.05). The advantages and disadvantages of the present models are discussed. Due to methodical problems and the marginal response to BCNU, autochthonous neurogenic tumors of the rat are not suitable as models for chemotherapeutic studies.