1,836 research outputs found
Elimination of Mange Mites Sarcoptes scabiei var. suis from Two Naturally Infested Danish Sow Herds Using a Single Injection Regime with Doramectin
Attempts to eliminate Sarcoptes scabiei var. suis were made in 2 naturally infested sow herds, by intramuscular (IM) injection of doramectin (Dectomax(®), Pfizer, New York, USA). A single injection strategy was used. In one of the herds, the environment was treated with an acaricide following dry cleaning of floors, walls and equipment. In the second herd, no environmental treatment was performed. Results were measured by skin lesion scoring, ear scrapings to show Sarcoptes scabiei var. suis, and calculating rubbing index throughout the observation period of 20 months following treatment. Skin lesion scores decreased and stayed low following treatment for the entire observation period. Live Sarcoptes scabiei var. suis mites were isolated prior to treatment from both herds, but not following treatment. Rubbing index decreased following treatment, but was occasionally at or above 0.4. The results of these studies indicate that elimination of Sarcoptes scabiei var. suis from 2 naturally infested herds was successful, using doramectin in a single injection strategy. Precautions must be taken to ensure adequate dosing of every pig, and to avoid reinfestation due to poor biosecurity
Prostacyclins have no direct inotropic effect on isolated atrial strips from the normal and pressure-overloaded human right heart
Prostacyclins are vasodilatory agents used in the treatment of pulmonary arterial hypertension. The direct effects of prostacyclins on right heart function are still not clarified. The aim of this study was to investigate the possible direct inotropic properties of clinical available prostacyclin mimetics in the normal and the pressure-overloaded human right atrium. Trabeculae from the right atrium were collected during surgery from chronic thromboembolic pulmonary hypertension (CTEPH) patients with pressure-overloaded right hearts, undergoing pulmonary thromboendarterectomy (n = 10) and from patients with normal right hearts operated by valve replacement or coronary bypass surgery (n = 9). The trabeculae were placed in an organ bath, continuously paced at 1 Hz. They were subjected to increasing concentrations of iloprost, treprostinil, epoprostenol, or MRE-269, followed by isoprenaline to elicit a reference inotropic response. The force of contraction was measured continuously. The expression of prostanoid receptors was explored through quantitative polymerase chain reaction (qPCR). Iloprost, treprostinil, epoprostenol, or MRE-269 did not alter force of contraction in any of the trabeculae. Isoprenaline showed a direct inotropic response in both trabeculae from the pressure-overloaded right atrium and from the normal right atrium. Control experiments on ventricular trabeculae from the pig failed to show an inotropic response to the prostacyclin mimetics. qPCR demonstrated varying expression of the different prostanoid receptors in the human atrium. In conclusion, prostacyclin mimetics did not increase the force of contraction of human atrial trabeculae from the normal or the pressure-overloaded right heart. These data suggest that prostacyclin mimetics have no direct inotropic effects in the human right atrium
Open Problems on Central Simple Algebras
We provide a survey of past research and a list of open problems regarding
central simple algebras and the Brauer group over a field, intended both for
experts and for beginners.Comment: v2 has some small revisions to the text. Some items are re-numbered,
compared to v
Expanding the Diagnostic Use of PCR in Leptospirosis: Improved Method for DNA Extraction from Blood Cultures
Background: Leptospirosis is a neglected zoonosis of ubiquitous distribution. Symptoms are often non-specific and may range from flu-like symptoms to multi-organ failure. Diagnosis can only be made by specific diagnostic tests like serology and PCR. In non-endemic countries, leptospirosis is often not suspected before antibiotic treatment has been initiated and consequently, relevant samples for diagnostic PCR are difficult to obtain. Blood cultures are obtained from most hospitalized patients before antibiotic therapy and incubated for at least five days, thus providing an important source of blood for PCR diagnosis. However, blood cultures contain inhibitors of PCR that are not readily removed by most DNAextraction methods, primarily sodium polyanetholesulfonate (SPS). Methodology/Principal Findings: In this study, two improved DNA extraction methods for use with blood cultures are presented and found to be superior in recovering DNA of Leptospira interrogans when compared with three previously described methods. The improved methods were easy and robust in use with all tested brands of blood culture media. Applied to 96 blood cultures obtained from 36 patients suspected of leptospirosis, all seven patients with positive convalescence serology were found positive by PCR if at least one anaerobic and one aerobic blood culture, sampled before antibiotic therapy were tested. Conclusions/Significance: This study suggests that a specific and early diagnosis can be obtained in most cases of sever
Evidence for Efimov quantum states in an ultracold gas of cesium atoms
Systems of three interacting particles are notorious for their complex
physical behavior. A landmark theoretical result in few-body quantum physics is
Efimov's prediction of a universal set of bound trimer states appearing for
three identical bosons with a resonant two-body interaction.
Counterintuitively, these states even exist in the absence of a corresponding
two-body bound state. Since the formulation of Efimov's problem in the context
of nuclear physics 35 years ago, it has attracted great interest in many areas
of physics. However, the observation of Efimov quantum states has remained an
elusive goal. Here we report the observation of an Efimov resonance in an
ultracold gas of cesium atoms. The resonance occurs in the range of large
negative two-body scattering lengths, arising from the coupling of three free
atoms to an Efimov trimer. Experimentally, we observe its signature as a giant
three-body recombination loss when the strength of the two-body interaction is
varied. We also detect a minimum in the recombination loss for positive
scattering lengths, indicating destructive interference of decay pathways. Our
results confirm central theoretical predictions of Efimov physics and represent
a starting point with which to explore the universal properties of resonantly
interacting few-body systems. While Feshbach resonances have provided the key
to control quantum-mechanical interactions on the two-body level, Efimov
resonances connect ultracold matter to the world of few-body quantum phenomena.Comment: 18 pages, 3 figure
Observation of an Efimov spectrum in an atomic system
In 1970 V. Efimov predicted a puzzling quantum-mechanical effect that is
still of great interest today. He found that three particles subjected to a
resonant pairwise interaction can join into an infinite number of loosely bound
states even though each particle pair cannot bind. Interestingly, the
properties of these aggregates, such as the peculiar geometric scaling of their
energy spectrum, are universal, i.e. independent of the microscopic details of
their components. Despite an extensive search in many different physical
systems, including atoms, molecules and nuclei, the characteristic spectrum of
Efimov trimer states still eludes observation. Here we report on the discovery
of two bound trimer states of potassium atoms very close to the Efimov
scenario, which we reveal by studying three-particle collisions in an ultracold
gas. Our observation provides the first evidence of an Efimov spectrum and
allows a direct test of its scaling behaviour, shedding new light onto the
physics of few-body systems.Comment: 10 pages, 3 figures, 1 tabl
Tumor heterogeneity in neoplasms of breast, colon, and skin
<p>Abstract</p> <p>Background</p> <p>Different cell subpopulations in a single tumor may show diverse capacities for growth, differentiation, metastasis formation, and sensitivity to treatments. Thus, heterogeneity is an important feature of tumors. However, due to limitations in experimental and analytical techniques, tumor heterogeneity has rarely been studied in detail.</p> <p>Presentation of the hypothesis</p> <p>Different tumor types have different heterogeneity patterns, thus heterogeneity could be a characteristic feature of a particular tumor type.</p> <p>Testing the hypothesis</p> <p>We applied our previously published mathematical heterogeneity model to decipher tumor heterogeneity through the analysis of genetic copy number aberrations revealed by array CGH data for tumors of three different tissues: breast, colon, and skin. The model estimates the number of subpopulations present in each tumor. The analysis confirms that different tumor types have different heterogeneity patterns. Computationally derived genomic copy number profiles from each subpopulation have also been analyzed and discussed with reference to the multiple hypothetical relationships between subpopulations in origin-related samples.</p> <p>Implications of the hypothesis</p> <p>Our observations imply that tumor heterogeneity could be seen as an independent parameter for determining the characteristics of tumors. In the context of more comprehensive usage of array CGH or genome sequencing in a clinical setting our study provides a new way to realize the full potential of tumor genetic analysis.</p
Axonal excitability does not differ between painful and painless diabetic or chemotherapy-induced distal symmetrical polyneuropathy in a multi-centre observational study
OBJECTIVE: Axonal excitability reflects ion channel function and it is proposed that this may be a biomarker in painful (versus painless) polyneuropathy. Our objective was to investigate the relationship between axonal excitability parameters and chronic neuropathic pain in deeply phenotyped cohorts with diabetic or chemotherapy induced distal symmetrical polyneuropathy. METHODS: 239 participants with diabetic polyneuropathy were recruited from sites in the UK and Denmark, and 39 participants that developed chemotherapy-induced polyneuropathy were recruited from Denmark. Participants were separated into those with probable or definite neuropathic pain and those without neuropathic pain. Axonal excitability of large myelinated fibres was measured with the threshold tracking technique. The stimulus site was the median nerve and the recording sites were the index finger (sensory studies) and abductor pollicis brevis muscle (motor studies). RESULTS: Participants with painless and painful polyneuropathy were well matched across clinical variables. Sensory and motor axonal excitability measures, including recovery cycle, threshold electrotonus, strength duration time constant, and current-threshold relationship, did not show differences between participants with painful and painless diabetic polyneuropathy, while there were only minor changes for chemotherapy-induced polyneuropathy. INTERPRETATION: Axonal excitability did not significantly differ between painful and painless diabetic or chemotherapy induced polyneuropathy in a multi-centre observational study. Threshold tracking assesses the excitability of myelinated axons; the majority of nociceptors are unmyelinated and although there is some overlap of the 'channelome' between these axonal populations, our results suggest that alternative measures such as microneurography are required to understand the relationship between sensory neuron excitability and neuropathic pain. This article is protected by copyright. All rights reserved
No difference in striatal dopamine transporter availability between active smokers, ex-smokers and non-smokers using [123I]FP-CIT (DaTSCAN) and SPECT
Background: Mesolimbic and nigrostriatal dopaminergic pathways play important roles in both the rewarding and conditioning effects of drugs. The dopamine transporter (DAT) is of central importance in regulating dopaminergic neurotransmission and in particular in activating the striatal D2-like receptors. Molecular imaging studies of the relationship between DAT availability/dopamine synthesis capacity and active cigarette smoking have shown conflicting results. Through the collaboration between 13 SPECT centres located in 10 different European countries, a database of FP-CIT-binding in healthy controls was established. We used the database to test the hypothesis that striatal DAT availability is changed in active smokers compared to non-smokers and ex-smokers. Methods: A total of 129 healthy volunteers were included. Subjects were divided into three categories according to past and present tobacco smoking: (1) non-smokers (n = 64), (2) ex-smokers (n = 39) and (3) active smokers (n = 26). For imaging of the DAT availability, we used [123I]FP-CIT (DaTSCAN) and single photon emission computed tomography (SPECT). Data were collected in collaboration between 13 SPECT centres located in 10 different European countries. The striatal measure of DAT availability was analyzed in a multiple regression model with age, SPECT centre and smoking as predictor. Results: There was no statistically significant difference in DAT availability between the groups of active smokers, ex-smokers and non-smokers (p = 0.34). Further, we could not demonstrate a significant association between striatal DAT and the number of cigarettes per day or total lifetime cigarette packages in smokers and ex-smokers. Conclusion: Our results do not support the hypothesis that large differences in striatal DAT availability are present in smokers compared to ex-smokers and healthy volunteers with no history of smoking
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