Emission of Parasitic X Rays of Vacuum-electron Tubes with Glass Housings: Implications for the Evaluation of Occupational Doses.

Despite the large variety of high-voltage semiconductor components for medium and high voltage switching and pulse-forming applications as well as for high-power high-frequency generation, the use of vacuum electron tubes still prevails to a considerable degree. Due to the common design incorporating a high energy electron beam which finally is dumped into an anode or a resonator cavity, these tubes are also considered as sources of X rays produced as bremsstrahlung and characteristic radiation, which are referred to as parasitic X rays. Here three types of vacuum-electron tubes, diode, tetrode, and thyratron, with glass housings are investigated. They are predominantly operated in the high voltage range below 30 kV and are not subject to licensing laws. The measurements of the dose rate and X-ray-spectra were performed in the laboratory without complex electrical circuitry usually used in making practical measurements for occupational radiation protection. For the diode tube, where a parasitic X-ray emission is observed only in the reverse operation as a blocking diode, a broad distribution of dose rates of electrically equivalent specimens was observed. This is attributed to field emission from the electrodes. For the tetrode and the thyratron tubes, field emission from the electrodes is identified as the dominant mechanism for the generation of parasitic X rays. Thus, technical radiation protection must focus on shielding of the glass tube rather than optimization of the electrical circuitry.

The scent of infanticide risk? Behavioural allocation to current and future reproduction in response to mating opportunity and familiarity with intruder.

ABSTRACT: The killing of young by unrelated males is widespread in the animal kingdom. In short-lived small rodents, females can mate immediately after delivery (post-partum oestrus) and invest in future reproduction, but infanticide may put the nestlings, their current reproductive investment, at risk. Here, we investigated the behavioural trade-offs between mating interest and nest protection in an arena experiment with bank voles (Myodes glareolus). Non-gravid females (n = 33) were housed at one end of a large structured arena with their nestlings. Different scents (cage bedding) were presented to each female in a replicated design. Three combinations of mating opportunities and male-female familiarity were simulated using different scent donors: mating opportunity with the sire of the nestlings with whom the female was familiar; mating opportunity with a male unrelated to the offspring and unfamiliar to the female, thus posing a higher risk to the offspring; and neither risk nor mating opportunity (clean control). Most females investigated male scents, regardless of familiarity, leaving their litter unprotected. During control treatment, females with larger litters spent less time at the scent area, indicating increasing nursing demands or better protection. Females with older litters visited scents more often, suggesting an increased interest in reproduction while they are non-gravid alongside the decreased risk of infanticide for older young. In the presence of unfamiliar scents, females spent more time protecting their nests, supporting the perceived association of unfamiliarity with infanticide risk. Thus, rodent females flexibly allocate time spent between searching for a mate and protecting their nest, which is modulated by their familiarity with a potential intruder. SIGNIFICANCE STATEMENT: Infanticide by conspecific males is an extreme form of sexual conflict and has large costs on females, abolishing their investment into current offspring. In an experimental approach, we exposed lactating female bank voles to different combinations of mating opportunity and familiarity to a (simulated) intruder: (1) the sire of the nestlings with whom the female was familiar and, therefore, potentially less risky in terms of infanticide; (2) a male which was unrelated and unfamiliar to the female and thus posed a higher risk to the offspring; or (3) as a control, cage bedding, which posed neither risk of infanticide nor a mating opportunity. We show that females flexibly allocated pup protection and mating interest based on their familiarity with the male, indicating that the unfamiliar males pose a threat to offspring, which is perceived by the females. Females further adjusted their behaviour to the size and/or age of their current litter, investing more time in male scents when offspring were older, thus balancing future and current investments into reproduction.

Ingestion of 226Ra from activated paints on military equipment: transfer factors and doses.

The use of 226Ra-activated markings was specific for military equipment some decades ago and the extent of possible internal exposure of former military personnel due to ingestion of 226Ra is an issue of discussion. Whole- or partial-body counts are not sensitive enough to trace an overexposure due to a possible 226Ra uptake four decades ago. Thus retrospective workplace assessments are needed. These are done by wiping tests with linen and skin pads on 226Ra markings on decommissioned military equipment. The contamination investigations are performed in wipe-activity measuring cycles with exponentially increasing numbers of wipes. The activity wiped off does not increase with the number of wipes but levels off instead. Wipes with linen pads are more effective than wipes with skin. The skin-skin activity transfer is investigated by respective wipes too. The maximum committed dose in a typical scenario is calculated under worst case assumptions. For the typical work of 1 y an effective dose of about 70 µSv, and for the bone surface a dose of about 3 mSv, is obtained.

Expression of ABC-transport proteins in canine mammary cancer: consequences for chemotherapy.

Intrinsic or acquired drug resistance is a major barrier for chemotherapy of cancer. Importantly, the presence of ATP-binding cassette, ABC-transport proteins in tumour cells circumvents an intracellular accumulation of chemotherapeutic drugs. In this study, 103 canine mammary tumour probes were investigated for mRNA expression of seven ABC-transporters by RT-PCR. All tumour samples expressed multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP). MRP7 was detected in 97.1% of tumour probes, MRP3 in 96.1%, Pgp in 92.2%, MRP5 in 85.4% and MRP6 in 64.1%. More of the half of tumour samples (56.1%) expressed all of the examined ABC-transport proteins. Approximately one-third of the tumour samples (32.7%) were lacking in one transporter and only 11.2% possessed from three to five transporters. The canine transporter cBCRP was functionally analysed in stable transfected Madin-Darby canine kidney-II cells using an MTT viability test. cBCRP transfected cells showed a 5.4-fold resistance to 10 microm doxorubicin. Cell survival in the presence of methotrexate was not affected by cBCRP. In conclusion, absence of efficiency of chemotherapy of canine mammary cancer can be caused by expression of seven various ABC-transport proteins. Because cBCRP is expressed in all examined tumour probes and induces resistance to doxorubicin, the application of doxorubicin for treatment of canine mammary is inappropriate.

[Etiology of the sugar beet rhizomania]. / Étiologie de la rhizomanie de la betterave sucrière.

Beet necrotic yellow vein virus is responsible for sugar beet rhizomania. Root proliferation is characteristic of the viral infection and lead to sugar losses. Pathogenicity is particularly linked to the expression of RNA-3-encoded p25. The extensive use of viral tolerant crops allows maintenance of sugar yields but also permits viruliferous vector to be maintained and therefore the appearance of resistance breaking isolates. The resistance breaking isolates present some amino acid variations within the p25 protein sequence, a key determinant in BNYVV pathogenicity. Here, we will review the molecular biology of BNYVV, of its vector and the antiviral strategies that may be used against rhizomania.

Influence of the angiotensin converting enzyme inhibitor ramipril on high-sensitivity C-reactive protein (hs-CRP) in patients with documented atherosclerosis.

UNLABELLED: Some medications have been shown to produce reductions in hs-CRP levels after initiating therapy. Whereas the role of the renin-angiotensin system in the inflammatory process has been documented in more detail during the last few years, the impact of an ACE-inhibitor therapy on this process has not been fully understood so far. The aim of this study was to investigate the effect of a therapy with the angiotensin-converting enzyme (ACE) inhibitor ramipril on hs-CRP plasma concentrations in patients with atherosclerosis. METHODS AND RESULTS: A total of 24 patients were enrolled in this prospective, uncontrolled, open-label multicenter study. Inclusion criteria were documented atherosclerosis, baseline high-sensitivity C-reactive protein between 3 and 12 mg/l, LDL-Cholesterol < or =150 mg/dl and no previous treatment with ACE inhibitors or angiotensin receptor blockers. Ten patients, pretreated with statins, and 10 patients not previously treated with statins were eligible for statistical analysis. Baseline high-sensitivity C-reactive protein was significantly decreased from 3.99+/-1.61 mg/l (mean+/-SD) to 2.72+/-1.19 mg/l (-32%) after 3 months treatment with 10 mg ramipril daily (p=0.0002). The decrease was more pronounced in patients who had not been treated with statins previously (-1.50 mg/l+/-1.44 mg/l) compared to those who were pretreated (-0.90 mg/l+/-0.93 mg/l). CONCLUSIONS: The ACE inhibitor ramipril administered in a daily dose of 10 mg to patients with atherosclerosis reduces the high-sensitivity C-reactive protein concentration. This effect may contribute to cardiovascular risk reduction mediated by ramipril aside from the blood pressure lowering effect.

[Cardiovascular risk stratification in general practice]. / Kardiovaskuläre Risikostratifizierung in der Allgemeinpraxis. Die Erfahrungen der Scoring-Woche 2002.

CONCLUSION: The ESC risk charts are helpful to identify high risk patients in general practice who are candidates for preventive treatment. The use of the ESC charts is one important step to initiate "evidence based medicine" in the daily practice of preventive cardiology.Cardiovascular diseases are the most important causes of premature disability and death in Germany. High risk patients however are frequently not recognized. A systematic risk stratification in general practice could identify high risk persons and allow a cost effective treatment approach. The goal of the CAD-scoring week was to identify high risk persons with the use of the ESC risk charts and to evaluate the treatment resulting from risk stratification. In addition the feasibility of the risk charts in daily office routine was to be evaluated. A total of 1122 of 20 000 (5.6%) contacted general physicians agreed to participate in the screening procedure. More than 27 000 patients (> 50 yrs) were evaluated using the ESC risk charts. 21.6% of women (n = 15 018) vs 22.2%* of men (n = 12 361) had markedly elevated blood pressure (> 150 mmHg), 29 vs. 24%* had a total cholesterol > 250 mg/dl (6.5 mmol/l), 25.5 vs 29.9%* smoked and 28.4 vs. 31.9%* had diabetes (*female vs male: p < 0.0003). Altogether 19.4% of women vs. 53% of men were newly identified as high risk patients (risk > 20% in 10 years). More than 40% of these high risk patients received drug treatment for prevention (ASA, lipid lowering drugs or ACE inhibitors). More than 70% of the participating physicians judged the risk charts to be helpful in patient management.

[Complication rate in the treatment of inter- and subtrochanteric femur fractures with two intramedullary osteosyntheses. Comparison of a conventional nailing system and a rotation stable fixation of the head-neck-fragment, gammanail and glidingnail]. / Komplikationsraten bei der Versorgung von per- und subtrochanteren Femurfrakturen mit zwei intramedullären Osteosyntheseverfahren. Vergleich eines konventionellen Nagelsystems mit einem rotationsstabilen Verfahren im Kopf-Hals-Fragment, Gammanagel und Gleitnagel.

Aim of the study was to evaluate typical complications in osteosynthesis of inter- and subtrochanteric femur fractures with intramedullary nailing systems. In the literature screw perforation of the femoral head into the acetabulum, postoperative fracture of the femur shaft, intraoperative shaft fracture, problems in placing of distal locking screws and deep infections are mostly described. In a retrospective study the complication rate of 100 consecutive gammanail osteosyntheses (GAN) and 96 glidingnail osteosyntheses (GLN) was analysed. 93 % of GAN and 89.3 % of GLN were followed up. Cutting out rate of GAN/GLN was 7.0 %/3.1 %, postoperative shaft fractures occurred in 1.0 %/0 %, intraoperative shaft fractures in 1.0 %/2.1 %, problems with distal locking in 2.0 %/1.0 % and deep infections in 3.0 %/1.0 %. In an analysis of internationally published data on 2 241 GAN and 365 GLN the cut-out rate was 2.3 %/0.5 %, postoperative shaft fracture 2.2 %/1.4 %, intraoperative shaft fracture 1.2 %/0.3 % and deep infection 1.2 %/2.2 %. GLN shows lower complication rates with regard to femoral head perforation and late shaft fracture than GAN.

Genetically engineered analogs of ascomycin for nerve regeneration.

The polyketides FK506 (tacrolimus) and FK520 (ascomycin) are potent immunosuppressants that function by inhibiting calcineurin phosphatase through formation of an FKBP12-FK506/520-calcineurin ternary complex. They also have calcineurin-independent neuroregenerative properties in cell culture and animal models of nervous system disorders. Based on the crystal structure of the FKBP12-FK506-calcineurin complex, we deduced that the 13- and 15-methoxy groups of FK506 or FK520 are important for inhibition of calcineurin phosphatase but not for binding to FKBP12. By genetic modification of the FK520 gene cluster, we generated 13- and 15-desmethoxy analogs of FK520 that contain hydrogen, methyl, or ethyl instead of methoxy at one or both of these positions. These analogs bind FKBP12 tightly, have decreased calcineurin phosphatase inhibition and immunosuppressive properties, and enhance neurite outgrowth in cell cultures. A representative compound was also shown to accelerate nerve regeneration and functional recovery in the rat sciatic nerve crush model.

Lateralization of prosody during language production: a lesion study.

To examine brain lateralization of prosody during speech, the sentence production of six right-hemisphere-lesion patients and five left-hemisphere-lesion patients was compared to that of seven normal controls using a question-answer paradigm. The task required the prosodic realization of two different syntactic structures under conditions of wide and narrow focus. Acoustical analyses were carried out on F0 and time structure. These analyses revealed a preserved ability in patients to express differences in syntactic structure via prosody. However, there were deficits in distinguishing narrow focus from wide focus. Whereas both right- and left-hemisphere lesions caused impairments in the realization of F0, time structure was mainly impaired in left-hemisphere patients. Therefore, the present results from language production support functional as well as cue-dependent hypotheses of the lateralization of prosodic processing in the brain.

Computational analysis of bacterial sulfatases and their modifying enzymes.

The sequence analysis of enzymes that might modify bacterial sulfatases should be useful in the task of identifying the human sulfatase-modifying homologs--enzymes that are defective in the rare inherited disease multi-sulfatase deficiency.

Biodegradation of polyhydroxyalkanoic acids.

Stimulated by the commercial availability of bacteriologically produced polyesters such as poly[(R)-3-hydroxybutyric acid], and encouraged by the discovery of new constituents of polyhydroxyalkanoic acids (PHA), a considerable body of knowledge on the metabolism of PHA in microorganisms has accumulated. The objective of this essay is to give an overview on the biodegradation of PHA. The following topics are discussed: (i) general considerations of PHA degradation, (ii) methods for identification and isolation of PHA-degrading microorganisms, (iii) characterization of PHA-degrading microorganisms, (iv) biochemical properties of PHA depolymerases, (v) mechanisms of PHA hydrolysis, (vi) regulation of PHA depolymerase synthesis, (vii) molecular biology of PHA depolymerases, (viii) influence of the physicochemical properties of PHA on its biodegradability, (ix) degradation of polyesters related to PHA, (x) biotechnological aspects of PHA and PHA depolymerases.

Isolation and identification of poly(3-hydroxyvalerate)-degrading strains of Pseudomonas lemoignei.

By using selective enrichment of polyhydroxyalkanoate-degrading bacteria and poly(3-hydroxyvalerate)-containing granules from Chromobacterium violaceum as the carbon source, 10 new Pseudomonas lemoignei strains were isolated; these strains were able to degrade poly(3-hydroxyvalerate), as well as poly(3-hydroxybutyrate), in vitro. The new isolates were characterized and identified by comparing them with P. lemoignei LMG 2207(T) (T = type strain). Like P. lemoignei LMG 2207(T) cells, the cells of the 10 new isolates contained mainly hexadecenoic, hexadecanoic, octadecenoic, and dodecanoic acids, as well as hydroxylated fatty acids, and exhibited respiration in the presence of methylpyruvate, 3-hydroxybutyrate, and 4-hydroxybutyrate, but not in the presence of the 92 other carbon sources included in Biolog GN microplates. The protein patterns of the new isolates were almost identical to each other and very similar to the protein pattern of P. lemoignei LMG 2207(T). Some of the new isolates, but not P. lemoignei LMG 2207(T), contained megaplasmids that were about 200 kbp long. The 16S ribosomal DNA genes of strain A62, a representative of the 10 new isolates, and of P. lemoignei LMG 2207(T) exhibited more than 0.99 sequence similarity. The DNA-DNA reassociation value for two representative strains was 100%, and the levels of DNA-DNA reassociation between these strains and the type strain were 60 and 61%. The taxonomy of P. lemoignei is briefly discussed.

Substrate specificities of poly(hydroxyalkanoate)-degrading bacteria and active site studies on the extracellular poly(3-hydroxyoctanoic acid) depolymerase of Pseudomonas fluorescens GK13.

The isolation of poly(3-hydroxyoctanoic acid)- and poly(6-hydroxyhexanoic acid)-degrading bacteria yielded 28 strains with abilities to degrade various polymers. The most versatile strains hydrolyzed five different polyesters comprising short chain length and medium chain length poly(hydroxyalkanoates). The new isolates together with previously isolated poly(hydroxyalkanoate)-degrading bacteria were classified into 11 groups with respect to their polymer-degrading specificities. All PHA depolymerases studied so far have been characterized by the lipase consensus sequence Gly-X-Ser-X-Gly in their amino acid sequence, which is a known sequence for serine hydrolases. When we replaced the central residue, Ser-172, in the corresponding sequence Gly-Ile-Ser-Ser-Gly of the extracellular poly(3-hydroxyoctanoic acid) depolymerase of Pseudomonas fluorescens GK13, with alanine the enzyme lost its activity completely. This result of the mutational experiment indicates that the poly(3-hydroxyoctanoic acid) depolymerase belongs to the family of serine hydrolases.

Molecular characterization of the extracellular poly(3-hydroxyoctanoic acid) [P(3HO)] depolymerase gene of Pseudomonas fluorescens GK13 and of its gene product.

phaZPfi, the gene encoding the extracellular poly(3-hydroxyoctanoic acid) depolymerase of Pseudomonas fluorescens GK13, was cloned, sequenced, and characterized. It comprises 837 bp and is transcribed as a monocistronic message of about 950 bp from a putative sigma 70-like promoter 32 bp upstream of the ATG start codon. The deduced protein of 278 amino acids reveals a typical leader peptide at its N terminus. When expressed in Escherichia coli, the mature depolymerase started with Ala-23, whereas the mature enzyme purified from P. fluorescens GK13 started with both Leu-34 and Arg-35 determining proteins of 26,687 and 26,573 Da, respectively. The depolymerase is a strongly hydrophobic protein and includes the lipase consensus sequence Gly-X-Ser-X-Gly, which is known for serine hydrolases. Replacement of the central residue, Ser-172, in the corresponding sequence (Gly-Ile-Ser-Ser-Gly) of PhaZPfl with alanine resulted in complete loss of enzyme activity, indicating that the poly(3-hydroxyoctanoic acid) depolymerase belongs to the family of serine hydrolases.

Serodiagnosis of Salmonella dublin infection in Danish dairy herds using O-antigen based enzyme-linked immunosorbent assay.

Usefulness of two enzyme-linked immunosorbent assays (ELISA) for screening of dairy herds for antibodies to lipopolysaccharide (LPS) of Salmonella dublin (O:1,9,12) was investigated. Sera (3097) were collected from 40 dairy herds located in three areas of Denmark with different prevalence of salmonellosis: ten salmonellosis-free herds from the island of Samsø where there is no history of salmonellosis, ten salmonellosis-free herds from the island of Sealand where outbreaks are infrequent, and 20 salmonella infected herds from Jutland where salmonellosis is enzootic. The samples were analyzed for antibodies to S. dublin LPS using an indirect (O:9,12) and a blocking (O:9) ELISA. Using herd history of salmonellosis, herd location and clinical state of the herds as reference, the herd sensitivity and herd specificity of the tests were 100% and 100% in the indirect ELISA and 95% and 100% in the blocking ELISA, respectively. A significant correlation was found between the two tests (rs = 0.46, p < 0.001). However, the indirect ELISA detected more seropositive animals than the blocking ELISA (17% vs. 7%, respectively). In calves from Sealand, level of background reaction was significantly lower (p < 0.001) compared to the heifers and the cows. The percentages of seropositive calves in both tests were higher (p < 0.01) in comparison to cows (19 vs. 8 in indirect ELISA, and 14 vs. 6 in blocking ELISA, respectively). Results of the study indicated that it is possible to apply LPS ELISA in serological screening for salmonellosis.

Detection of Actinobacillus pleuropneumoniae serotype 2 antibodies in pig sera by an inhibition enzyme immuno assay (EIA).

An inhibition Enzyme Immuno Assay (EIA) for detection of antibodies against A. pleuropneumoniae serotype 2 (App-2) in pig sera, based on the inhibition of the binding of an App-2 specific monoclonal antibody was established. The monoclonal antibody (mAb 102-G02) was found to be directed against an epitope on the O-chain of App-2 LPS. Some App-2 isolates did not react with the mAb 102-G02. These isolates are referred to as App-2X. In the inhibition EIA highly purified App-2 LPS ws used to coat microtiter plates. Serial dilutions of pig sera were added to the plates prior to the mAb 102-G02. The degree of binding of App-2 antibodies from pig sera was determined as the percentage inhibition of the mAb 102-G02. Pig sera from specific pathogen free (SPF) herds, from experimentally infected animals, and from conventionel herds were tested. A serum dilution of 1/200 was found to be optimal, when using 50% inhibition as the discriminating inhibition percentage. Serum from App-2X infected herds showed a lower reactivity as compared to serum from App-2 infected herds. No crossreactivity was observed with serum from pigs infected with other App serotypes. The sensitivity and specificity were 100% and 98.9%, respectively.

Degradation of poly(3-hydroxyoctanoic acid) [P(3HO)] by bacteria: purification and properties of a P(3HO) depolymerase from Pseudomonas fluorescens GK13.

Twenty-five gram-negative bacteria and one gram-positive bacterium capable of growing on poly(3-hydroxyoctanoic acid) [P(3HO)] as the sole source of carbon and energy were isolated from various soils, lake water, and activated sludge. Most of the isolates degraded only P(3HO) and copolymers of medium-chain-length (MCL) hydroxyalkanoic acids (HA). Except for the gram-positive strain, which was able to hydrolyze P(3HO) and poly(3-hydroxybutyric acid) [P(3HB)], no isolate was able to degrade polymers of short-chain-length HA, such as P(3HB) or poly(3-hydroxyvalerate) [P(3HV)]. All strains utilized a large variety of monomeric substrates for growth. All gram-negative strains, but not the gram-positive strain, accumulated poly(hydroxyalkanoic acids) (PHA), consisting of MCL HA, if they were cultivated under accumulation conditions. One strain, which was identified as Pseudomonas fluorescens GK13 (biovar V), was selected and the extracellular P(3HO) depolymerase of this strain was purified from the culture medium of P(3HO)-grown cells by chromatography with Octyl-Sepharose CL4B and by gel filtration with Superose 12. The relative molecular weights of the native and sodium dodecyl sulfate-treated enzymes were 48,000 and 25,000, respectively. The purified enzyme hydrolyzed P(3HO), copolymers of MCL HA, and para-nitrophenyl esters of fatty acids. P(3HB), P(3HV), and characteristic substrates for lipases, such as Tween 80 or triolein, were not hydrolyzed. The P(3HO) depolymerase of P. fluorescens GK13 was insensitive to phenylmethylsulfonyl fluoride and dithioerythritol, unlike other PHA depolymerases. The dimeric ester of 3-hydroxyoctanoic acid was identified as the main product of enzymatic hydrolysis of P(3HO).(ABSTRACT TRUNCATED AT 250 WORDS)

Functional studies on platelets of a patient with an acquired disorder of platelet function associated with autoantibodies against membrane glycoprotein IIB/IIIA complex.

Platelet functions have been studied of a 63 year old woman with a severe acquired thrombopathy. The platelets did not adhere to siliconized glass. Aggregation could not be induced by either ADP (1 microM) nor collagen (2 micrograms/ml), no release of serotonin was found under these conditions. Thrombin caused only a weak aggregation response. Quantitative analysis of platelet actin revealed a very low total actin content (473 micrograms/10(9) platelets) and an extremely low F-actin value (3% of total actin). Stimulation of platelets with 0.1 U/ml thrombin for 3 min resulted in an increase of only 5% F-actin, whereas ADP and collagen did not induce any actin polymerization. Ca2+ movement in the patient's platelets is severely impaired after ADP and collagen stimulation, whereas a normal Ca2+ movement was obtained by 0.1 U/ml thrombin. The inhibition of the functions of normal platelets (aggregation and actin polymerization) by addition of patient's serum (5-10% final concentration) points to receptor blockade by platelet autoantibodies in the patient's serum. The antibody was purified by adsorption on Protein-A-Sepharose. Addition of IgG-suspension (5% final concentration) to washed control platelets resulted in similar effects on aggregation and actin polymerization compared to the effects of patient's serum.