Comparison of the Radiation Dose from Cone Beam Computed Tomography and Multidetector Computed Tomography in Examinations of the Hand.

PURPOSE: Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand. MATERIALS AND METHODS: Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures < 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose. RESULTS: The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT. CONCLUSION: Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization. KEY POINTS: • Low dose examinations of the hand are feasible in CBCT and MDCT.• In default settings CBCT has a lower dose than MDCT.• MDCT enables a good image quality at a lower dose than CBCT. Citation Format: • Neubauer J, Neubauer C, Gerstmair A et al. Comparison of the Radiation Dose from Cone Beam Computed Tomography and Multidetector Computed Tomography in Examinations of the Hand. Fortschr Röntgenstr 2016; 188: 488 - 493.

Lipid remodeling in Rhodopseudomonas palustris TIE-1 upon loss of hopanoids and hopanoid methylation.

The sedimentary record of molecular fossils (biomarkers) can potentially provide important insights into the composition of ancient organisms; however, it only captures a small portion of their original lipid content. To interpret what remains, it is important to consider the potential for functional overlap between different lipids in living cells, and how the presence of one type might impact the abundance of another. Hopanoids are a diverse class of steroid analogs made by bacteria and found in soils, sediments, and sedimentary rocks. Here, we examine the trade-off between hopanoid production and that of other membrane lipids. We compare lipidomes of the metabolically versatile α-proteobacterium Rhodopseudomonas palustris TIE-1 and two hopanoid mutants, detecting native hopanoids simultaneously with other types of polar lipids by electrospray ionization mass spectrometry. In all strains, the phospholipids contain high levels of unsaturated fatty acids (often >80%). The degree to which unsaturated fatty acids are modified to cyclopropyl fatty acids varies by phospholipid class. Deletion of the capacity for hopanoid production is accompanied by substantive changes to the lipidome, including a several-fold rise of cardiolipins. Deletion of the ability to make methylated hopanoids has a more subtle effect; however, under photoautotrophic growth conditions, tetrahymanols are upregulated twofold. Together, these results illustrate that the 'lipid fingerprint' produced by a micro-organism can vary depending on the growth condition or loss of single genes, reminding us that the absence of a biomarker does not necessarily imply the absence of a particular source organism.

Characterization of Pasteurellaceae-like bacteria isolated from clinically affected psittacine birds.

AIMS: The aim of the present investigation was to identify and characterize Pasteurella-like isolates obtained from clinically affected psittacine birds. METHODS AND RESULTS: A total of 37 isolates from psittacine birds tentatively classified with the family Pasteurellaceae were characterized phenotypically. The genetic relationship was investigated by sequencing of partial rpoB and 16S rRNA genes for selected isolates. The results obtained were compared with the data from 16 reference strains. Nine isolates were identified as Gallibacterium spp., 16 as Volucribacter spp. or Volucribacter-like, while 11 isolates were classified as taxon 44 of Bisgaard. A single isolate was identified as Pasteurella multocida. CONCLUSIONS: Characterization of Pasteurellaceae by traditional methods is often inconclusive because of inconsistent reactions and phenotypic diversity. For the same reason, genotyping is essential to allow proper classification as demonstrated in the present study. SIGNIFICANCE AND IMPACT OF THE STUDY: Limited information exists on the isolation and significance of Pasteurellaceae associated with clinically affected psittacine birds showing signs of digestive and/or respiratory disorders. The present investigations demonstrated that these organisms are widely distributed among clinically affected birds, but isolation of these taxa cannot be unambiguously correlated with the symptoms observed.

Tissue distribution of haemolytic Gallibacterium anatis isolates in laying birds with reproductive disorders.

Gallibacterium anatis biovar haemolytica has been suggested to have a causal role in peritonitis and salpingitis in chickens. Therefore, the aim of this study was to investigate the occurrence of G. anatis biovar haemolytica in chickens with reproductive disorders. One hundred and forty one birds from 31 layer flocks were submitted for necropsy and the following organs were examined for bacteria: choana, trachea, lung, heart, liver, spleen, ovary, oviduct, duodenum and cloaca. Examination for Escherichia coli was included as it can induce reproductive disorders. G. anatis was isolated in pure culture from the reproductive tract of affected birds in six of the 31 flocks while E. coli was obtained in pure culture from 10 of them. Both G. anatis and E. coli were isolated from the reproductive tract of 14 of the 31 flocks. The genetic diversity of the Gallibacterium isolates was assessed by amplified fragment length polymorphism on a subset of 83 isolates. Generally, each flock was infected with a single clone, which could be isolated from various sites in the birds. However, in two flocks, the majority of birds yielded positive samples from the internal organs, indicating that these particular clones may be more invasive. The findings support previous suggestions that G. anatis biovar haemolytica is associated with infection of the reproductive tract of chickens, making it a likely cause of lowered productivity and an animal welfare concern.

Peganum harmala can minimize Escherichia coli infection in poultry, but long-term feeding may induce side effects.

Peganum harmala seed extracts have been frequently reported to possess antibacterial potential through in vitro studies, but in vivo studies have acquired less attention. The present study was therefore designed to investigate its efficacy on the course of colibacillosis and effects of long-term feeding on selected parameters of general health in chickens. Two experiments were conducted in this regard. Experiment 1 (a pilot study) was performed to determine the dose of a field strain of Escherichia coli (O1:K1) required to induce clinical symptoms in 4- and 15-d-old specific-pathogen-free chickens. A successful induction of colibacillosis, in terms of clinical signs, mortality, and pathological lesions in addition to reisolation of the pathogen was observed by inoculating 4- and 15-d-old chicks with 4.3 log(10) and 6.4 log(10) cfu of E. coli, respectively, by intraperitoneal injection. Using these doses experiment 2 (main study) consisting of a single experiment with 3 parts was performed. Parts A and B generated the information regarding efficacy of the extract against infection in 4- and 15-d-old chickens applying different treatment schemes, whereas the effects of continuous feeding of the extract were assessed in part C. Whereas no protective effect of the extract could be recorded in young chickens, significant differences (P < 0.05) with regard to BW, clinical score, gross lesion score, and total granulocyte counts were observed in 15-d-old birds. Bacterial recovery per gram of tissue and reisolation frequency were lower in treated birds. The continuous feeding of the extract for 6 wk resulted in an augmentation in relative liver weight and depletion in alkaline phosphatase, protein, albumin, and globulin. It can be concluded that the crude extract of Peganum harmala possesses limited antimicrobial activity against E. coli in vivo and long-term continuous feeding may induce undesired effects. Furthermore, the study underlines the value of in vivo experiments and the diverse picture that herbal products, in this case Peganum harmala, may deliver by testing them against specific pathogens.

Interlaboratory comparison of ability to detect nucleic acid of Mycoplasma gallisepticum and Mycoplasma synoviae by polymerase chain reaction.

In recent years polymerase chain reaction (PCR) assays have become widely used as methods to confirm the presence of Mycoplasma gallisepticum and Mycoplasma synoviae in poultry flocks, but there has been limited standardization of the protocols used. Thirteen laboratories from five different countries participated in an interlaboratory comparison of detection of M. gallisepticum and M. synoviae DNA by PCR in samples that contained 10-fold dilutions of these bacteria. The concentration of bacteria ranged from 10(5) to 10(2) genome copies/100 microl sample, as quantified by real-time PCR, and the samples were supplied on dry cotton swabs. Each laboratory was asked to use its standard method for PCR testing of these pathogens. A questionnaire was supplied with the samples to obtain details of the methods that were used in testing. One-half of the laboratories used a commercially available test kit, while the others used an in-house protocol. The protocols used for DNA extraction varied greatly, even among those using commercially available test kits. Two laboratories had developed the primers for nucleic acid amplification themselves, and one of these used real-time PCR for amplification. While the majority of the laboratories detected M. synoviae down to the 100 copy limit of the comparison, the detection limit for M. gallisepticum was somewhat higher. Furthermore, different results were obtained from laboratories that used the same commercial test kit. To the best of our knowledge this is the first investigation of its kind in the field of avian diseases.

Detection and identification of food-borne pathogens of the genera Campylobacter, Arcobacter and Helicobacter by multiplex PCR in poultry and poultry products.

The objective of this study was to develop a multiplex polymerase chain reaction (PCR) to detect and differentiate food-borne pathogens of the three genera Campylobacter, Arcobacter and Helicobacter in a single step procedure. One common reverse primer and three genus-specific forward primers were designed by hybridizing to the 16S rRNA of selected reference strains. Besides the species with significance as food-borne pathogens isolated from poultry meat--Campylobacter jejuni, Campylobacter coli, Arcobacter butzleri and Helicobacter pullorum--several other members of these genera were tested to determine the specificity of the designed multiplex PCR. In total, 20 ATCC and NCTC reference strains of Campyobacter, Arcobacter and Helicobacter were used to evaluate the PCR. Specific amplificates were obtained from all thermophilic species of Campylobacter as well as from species of Arcobacter and Helicobacter. No amplification product was obtained from the non-thermophilic Campylobacter, C. hyointestinalis and C. fetus. Furthermore, a total of 43 field strains of the three genera isolated from poultry, pigs, cattle and humans were investigated using this PCR. To confirm the classification of 10 H. pullorum strains the 16S rRNAs were sequenced. The developed PCR is a helpful diagnostic tool to detect and differentiate Campylobacter, Arcobacter and Helicobacter isolated from poultry and poultry products.

Phenotypic and genotypic differentiation of Campylobacter spp. isolated from Austrian broiler farms: a comparison.

An identification scheme based on restriction fragment length polymorphism of polymerase chain reaction products (PCR-RFLP) was developed to differentiate isolates of the genera Campylobacter, Arcobacter and Helicobacter. Based on the 16S rRNA gene of these genera, PCR amplified a 1216-bp fragment. The amplicons were digested with the restriction enzymes RsaI and EcoRV. Additional differentiation was obtained using a PCR-assay based on the hippuricase gene. Genotyping was performed on several reference strains from the National Collection of Typing Culture (NCTC), London, and on 130 field isolates. In parallel, a phenotypic differentiation was performed, in order to compare the results. In 119 cases (91.5%) the results obtained from the genotypic characterization were concordant with those from phenotypic testing. Co-infections with Campylobacter jejuni and Campylobacter coli in two samples and seven hippurate-negative C. jejuni-strains were identified by the genotypic method. Furthermore, PCR-RFLP assays identified an atypical isolate as Campylobacter fetus/hyointestinalis.

[The role of low-molecular-weight heparin in unstable angina, acute myocardial infarction and post-elective percutaneous transluminal coronary angioplasty]. / O papel da heparina de baixo peso molecular na angina instável, infarto agudo do miocárdio e pós-angioplastia percutânea transluminal coronária eletiva.

PURPOSE: To evaluate the clinical efficacy and safety of subcutaneous (SC) low molecular weight heparin (LMWH) compared to intravenous (IV) non fractioned heparin (NFH) in unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty. METHODS: From September/92 to April/94, 314 patients were randomized in two groups. Group I-- 154 patients treated with SC LMWH, using in the 1st phase SC LMWH with a dosage of 160 UaXa IC/kg/day (group IA--92 patients), and in the 2nd, a dosage of 320 UaXa IC/kg/day (group IB--62 patients). Group II--160 patients treated with IV NFH 100UI/kg (bolus), followed by 1000UI/h with adjusted dosage by activated partial thromboplastin time. RESULTS: There was not a statistically significant difference among the three groups in relation to cardiac events, hemorrhagic complications and deaths. CONCLUSION: The clinical efficacy and safety of SC LMWH in patients with unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty were similar to IV NFH with the dosages used in this study.

Serum dehydroepiandrosterone and cortisol measurements in Huntington's chorea.

Serum levels of dehydroepiandrosterone sulfate (DHEAS), known to antagonize metabolic effects of glucocorticoids in animals, and cortisol (CRT), already shown to be related to cognitive dysfunction in man and animals, were measured in 11 drug-free male subjects with definite Huntington's chorea (HC) and in 25 age-matched male normal controls. Statistical difference was found between DHEAS serum levels (p < 0.05), CRT levels (p < 0.05) and the DHEAS/CRT ratio (p < 0.01) of HC subjects and normal individuals. These findings may indicate a dysfunction of the hypothalamic-pituitary-adrenal axis (HPAA) and possibly suggest a role of DHEAS as an antiglucocorticoid in HC.

Athermal alterations in the structure of the canalicular membrane and ATPase activity induced by thermal levels of microwave radiation.

Sprague-Dawley rats (200-250 g) were exposed 30 min/day for 4 days to thermogenic levels (rectal temperature increase of 2.2 degrees C) of microwave radiation [2.45 GHz, 80 mW/cm2, continuous-wave mode (CW)] or to a radiant heat source resulting in an equivalent increase in body temperature of 2.2 degrees C. On the fifth day after the 4 days of exposure to microwave radiation, the animals were sacrificed and their livers removed. The canalicular membranes were isolated and evaluated for adenosinetriphosphatase (ATPase) activity, total fatty acid composition and membrane fluidity characteristics. Mg(++)-ATPase activity (Vmax) decreased by 48.5% in the group exposed to microwave radiation, with no significant change in the group exposed to radiant heat. The decrease in Mg(++)-ATPase was partially compensated by a concomitant increase in Na+/K(+)-ATPase activity (170% increase in Vmax over control) in animals exposed to microwave radiation, while no change occurred in the group exposed to radiant heat. This alteration in ATPase activity in the group exposed to microwave radiation is associated with a large decrease in the ratio of saturated to unsaturated fatty acids. Conversely, the group exposed to radiant heat had an increase in the ratio of saturated to unsaturated fatty acids. The most dramatic changes were found in the levels of arachidonic acid. Finally, the electron paramagnetic resonance (EPR) spin label technique used to measure the fluidity of the canalicular membranes of the animals in the three groups (sham, microwave radiation and radiant heat) indicated that the results were different in the three groups, reflecting the changes found in their fatty acid composition. The physiological response to "equivalent" thermal loads in rats is expressed differently for different types of energy sources. Possible mechanisms producing these divergent thermogenic responses are discussed.

An active Mehler-peroxidase reaction sequence can prevent cyclic PS I electron transport in the presence of dioxygen in intact spinach chloroplasts.

Simultaneous measurements of 9-aminoacridine (9-AA) fluorescence quenching, O2-uptake and chlorophyll fluorescence of intact spinach chloroplasts were carried out to assess the relationship between the transthylakoidal ΔpH and linear electron flux passing through Photosystem II. Three different types of O2-dependent electron flow were investigated: (1) Catalysed by methyl viologen; (2) in the absence of a catalyst and presence of an active ascorbate peroxidase (Mehler-peroxidase reaction); (3) in the absence of a catalyst and with the ascorbate peroxidase being inhibited by KCN (Mehler reaction). The aim of this study was to assess the relative contribution of ΔpH-formation which is not associated with electron flow through Photosystem II and, which should reflect Photosystem I cyclic flow under the different conditions. The relationship between the extent of 9-AA fluorescence quenching and O2-uptake rate was found to be almost linear when methyl viologen was present. In the absence of methyl viologen (Mehler reaction) an increase of 9-AA fluorescence quenching to a value of 20% at low light intensities was associated with considerably less O2-uptake than in the presence of methyl viologen, indicating the involvement of cyclic flow. These findings are in agreement with a preceding study of Kobayashi and Heber (1994). However, when no KCN was added, such that the complete Mehler-peroxidase reaction sequence was operative, the relationship between 9-AA fluorescence quenching and the flux through PS II, as measured via the chlorophyll fluorescence parameter ΔF/Fm' × PAR, was identical to that observed in the presence of methyl viologen. Under the assumption that methyl viologen prevents cyclic flow, it is concluded that there is no significant contribution of cyclic electron flow to ΔpH-generation in intact spinach chloroplasts.

Membrane barriers and Mehler-peroxidase reaction limit the ascorbate available for violaxanthin de-epoxidase activity in intact chloroplasts.

The presence of an acidic lumen and the xanthophylls, zeaxanthin and antheraxanthin, are minimal requirements for induction of non-radiative dissipation of energy in the pigment bed of Photosystem II. We recently reported that ascorbate, which is required for formation for these xanthophylls, also can mediate the needed lumen acidity through the Mehler-peroxidase reaction [Neubauer and Yamamoto (1992) Plant Physiol 99: 1354-1361]. It is demonstrated that in non-CO2-fixing intact chloroplasts and thylakoids of Lactuca sativa, L. c.v. Romaine, the ascorbate available to support de-epoxidase activity is influenced by membrane barriers and the ascorbate-consuming Mehler-peroxidase reaction. In intact chloroplasts, this results in biphasic kinetic behavior for light-induced de-epoxidation. The initial relatively high activity is due to ascorbate preloaded into the thylakoid before light-induction and the terminal low activity due to limiting ascorbate from the effects of chloroplast membranes barriers and a light-dependent process. A five-fold difference between the initial and final activities was observed for light-induced de-epoxidation in chloroplasts pre-incubated with 120 mM ascorbate for 40 min. The light-dependent activity is ascribed to the competitive use of ascorbic acid by ascorbate peroxidase in the Mehler-peroxidase reaction. Thus, stimulating ascorbic peroxidase with H2O2 transiently inhibited de-epoxidase activity and concomitantly increased photochemical quenching. Also, the effects inhibiting ascorbate peroxidase with KCN, and the KM values for ascorbate peroxidase and violaxanthin de-epoxidase of 0.36 and 3.1 mM, respectively, support this conclusion. These results indicate that regulation of xanthophyll-dependent non-radiative energy dissipation in the pigment bed of Photosystem II is modulated not only by lumen acidification but also by ascorbate availability.

On the relationship between chlorophyll fluorescence quenching and the quantum yield of electron transport in isolated thylakoids.

The relationship between the empirical fluorescence index ΔF/Fm' and the quantum yield of linear electron flow, Φ(s), was investigated in isolated spinach thylakoids. Conditions were optimised for reliable determination of ΔF/Fm' and Φ(s) with methyl viologen or ferricyanide as electron acceptors under coupled and uncoupled conditions. Ascorbate in combination with methyl viologen was found to stimulate light-induced O2-uptake which is not reflected in ΔF/Fm' and interpreted to reflect superoxide reduction by ascorbate. In the absence of ascorbate, the plot of ΔF/Fm' vs. Φ(s) was mostly linear, except for the range of high quantum yields, i.e. at rather low photon flux densities. With ferricyanide as acceptor, use of relatively low concentrations (0.1-0.3 mM) was essential for correct Fm'-determinations, particularly under uncoupled conditions. Under coupled and uncoupled conditions the same basic relationship between ΔF/Fm' and Φ(s) was observed, irrespective of Φ(s) being decreased by increasing light intensity or by DCMU-addition. The plots obtained with methyl viologen and ferricyanide as acceptors were almost identical and similar to corresponding plots reported previously by other researchers for intact leaves. It is concluded that the index ΔF/Fm' can be used with isolated chloroplasts for characterisation of such types of electron flow which are difficult to assess otherwise, as e.g. O2 dependent flux. The origin of the 'non-linear' part of the relationship is discussed. An involvement of 'inactive' PS II centers with separate units and inefficient QA-QB electron transfer is considered likely.

Multiple Effects of Dithiothreitol on Nonphotochemical Fluorescence Quenching in Intact Chloroplasts (Influence on Violaxanthin De-epoxidase and Ascorbate Peroxidase Activity).

Reversible nonphotochemical fluorescence quenching depends on thylakoid lumen acidification and violaxanthin de-epoxidation and is correlated with photoprotection of photosynthesis. The O2-dependent electron flow in the coupled Mehler-ascorbate peroxidase reaction (MP-reaction) mediates the electron flow necessary for lumen acidification and violaxanthin de-epoxidation in isolated, intact chloroplasts. Inhibition of violaxanthin de-epoxidation by dithiothreitol (DTT) was correlated with suppression of fluorescence quenching. In addition, DTT was also found to suppress fluorescence quenching due to inhibition of ascorbate peroxidase activity, a main enzyme of the MP-reaction, even in the presence of zeaxanthin. In intact, non-CO2-fixing chloroplasts, violaxanthin and antheraxanthin de-epoxidation and the ascorbate peroxidase activity show different sensitivities to increasing DTT concentrations. Violaxanthin de-epoxidase activity, measured as the sum of zeaxanthin and antheraxanthin formed, was inhibited with an inhibitor concentration for 50% inhibition (I50) of 0.35 mM DTT. In contrast, inhibition of the O2-dependent electron flow and corresponding lumen acidification occurred with higher I50 values of 2.5 and 3 mM DTT, respectively, and was attributed to inhibition of ascorbate peroxidase activity (I50 = 2 mM DTT). Accordingly, the DTT-induced inhibition of the nigericin-sensitive nonphotochemical fluorescence quenching was correlated linearly with the decreasing concentrations of zeaxanthin and antheraxanthin and was almost unaffected by DTT inhibition of the MP-reaction and correlated [delta]pH. The nigericin-insensitive, photoinhibitory kind of nonphotochemical fluorescence quenching up to 1 mM was mainly correlated with inhibition of violaxanthin de-epoxidation. At higher DTT concentrations, it was attributed to inhibition of both violaxanthin de-epoxidation and MP-reaction. The results show that DTT has multiple, but distinguishable, effects on nonphotochemical fluorescence quenching in isolated chloroplasts, necessitating careful interpretation.

Age and sex differences of dehydroepiandrosterone sulfate (DHEAS) and cortisol (CRT) plasma levels in normal controls and Alzheimer's disease (AD).

In 50 healthy subjects (23 female, 27 male, aged 18-81) and 24 patients with Alzheimer's disease (AD) (11 female, 13 male, aged 58-88) DHEAS and CRT plasma levels were studied. In normal subjects there was a clear negative correlation of DHEAS to age, while no significant age correlated decrease of CRT plasma levels was found. There was a significant decrease in the DHEAS/CRT ratio in elderly controls (aged > 60) as compared to young individuals (aged < 45). Overall there was a trend to lower DHEAS/CRT ratios in AD patients compared to age matched controls out of the total group of normals (P < 0.1), there was a significant decrease of this ratio in female AD patients (P < 0.05), compared to age matched female controls, but there was none in male Alzheimers; furthermore there was a significant difference in CRT plasma levels between female AD patients and age matched female controls (P < 0.01) and between female and male AD patients (P < 0.05). Considering the antiglucocorticoid effects of DHEAS, this ratio may account for its protective effect against hippocampal degeneration caused by glucocorticoids and possibly for the higher rate of AD in females.