470 research outputs found

    Mitochondrial DNA Content in Human Omental Adipose Tissue

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    Background: Impairment of mitochondrial function plays an important role in obesity and the development of insulin resistance. The aim of this project was to investigate the mitochondrial DNA copy number in human omental adipose tissue with respect to obesity. Methods: The mitochondrial DNA (mtDNA) content per single adipocyte derived from abdominal omental adipose tissue was determined by quantitative RT-PCR in a group of 75 patients, consisting of obese and morbidly obese subjects, as well as non-obese controls. Additionally, basal metabolic rate and fat oxidation rate were recorded and expressed as total values or per kilogram fat mass. Results: MtDNA content is associated with obesity. Higher body mass index (BMI) resulted in a significantly elevated mtDNA count (ratio = 1.56; p = 0.0331) comparing non-obese (BMI < 30) to obese volunteers (BMI ≥ 30). The mtDNA count per cell was not correlated with age or gender. Diabetic patients showed a trend toward reduced mtDNA content. A seasonal change in mtDNA copy number could not be identified. In addition, a substudy investigating the basal metabolic rate and the fasting fat oxidation did not reveal any associations to the mtDNA count. Conclusions: The mtDNA content per cell of omental adipose tissue did not correlate with various clinical parameters but tended to be reduced in patients with diabetes, which may partly explain the impairment of mitochondrial function observed in insulin resistance. Furthermore, the mtDNA content was significantly increased in patients suffering from obesity (BMI above 30). This might reflect a compensatory response to the development of obesity, which is associated with impairment of mitochondrial functio

    Lack of phenotypic and evolutionary cross-resistance against parasitoids and pathogens in Drosophila melanogaster

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    BackgroundWhen organisms are attacked by multiple natural enemies, the evolution of a resistance mechanism to one natural enemy will be influenced by the degree of cross-resistance to another natural enemy. Cross-resistance can be positive, when a resistance mechanism against one natural enemy also offers resistance to another; or negative, in the form of a trade-off, when an increase in resistance against one natural enemy results in a decrease in resistance against another. Using Drosophila melanogaster, an important model system for the evolution of invertebrate immunity, we test for the existence of cross-resistance against parasites and pathogens, at both a phenotypic and evolutionary level.MethodsWe used a field strain of D. melanogaster to test whether surviving parasitism by the parasitoid Asobara tabida has an effect on the resistance against Beauveria bassiana, an entomopathogenic fungus; and whether infection with the microsporidian Tubulinosema kingi has an effect on the resistance against A. tabida. We used lines selected for increased resistance to A. tabida to test whether increased parasitoid resistance has an effect on resistance against B. bassiana and T. kingi. We used lines selected for increased tolerance against B. bassiana to test whether increased fungal resistance has an effect on resistance against A. tabida.Results/ConclusionsWe found no positive cross-resistance or trade-offs in the resistance to parasites and pathogens. This is an important finding, given the use of D. melanogaster as a model system for the evolution of invertebrate immunity. The lack of any cross-resistance to parasites and pathogens, at both the phenotypic and the evolutionary level, suggests that evolution of resistance against one class of natural enemies is largely independent of evolution of resistance against the other

    On the evolution of the tymbalian tymbal organ: Comment on “Planthopper bugs use a fast, cyclic elastic recoil mechanism for effective vibrational communication at small body size” by Davranoglou et al. 2019

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    In ihrer kürzlich erschienenen Arbeit (Davranoglou et al. 2019) untersuchten die Autoren an lebenden Exemplaren von Agalmatium bilobium (Issidae) mit modernsten Methoden (microCT) die Interaktionen zwischen Muskulatur und bestimmten Anteilen des Exoskeletts zur Vibrationserzeugung und beschreiben deren biomechanische Grundlage. Auf der Basis des morphologischen Vergleichs mit Museumsmaterial von Vertretern der meisten Taxa der Fulgoromorpha (Spitzkopfzikaden) im Familienrang postulieren Davranoglou et al. (2019), ein „neues und bisher übersehenes“ Organ entdeckt zu haben, das sie als „snapping organ“ bezeichnen und als charakteristisch für die Fulgoromorpha (mit Ausnahme der Delphacidae) interpretieren. Wir sehen diese Ergebnisse aus folgenden Gründen kritisch: 1. In ihrer umfassenden Übersicht zu den vibrationserzeugenden Organen der Hemiptera stellten Wessel et al. (2014) die Hypothese auf, dass sich alle bisher bekannten Strukturen zur Schall- und Vibrationserzeugung auf ein Organ zurückführen lassen, das mit hoher Wahrscheinlichkeit bei der Stammart aller Hemipteren oberhalb der Sternorrhyncha vorhanden war, und eine Synapomorphie dieses Taxons, der sog. Tymbalia (Wessel et al. 2014), darstellt. Da aufgrund der morphologischen Disparität des Organs in den einzelnen Taxa die Homologieverhältnisse schwierig zu beurteilen sind, stellten Wessel et al. (2014) Kriterien für das „Tymbal der Tymbalia“ auf. Das sogenannte „snapping organ“ erfüllt alle Kriterien dieses Tymbal-Organes. Die Einführung eines neuen Begriffes für eine bestimmte Struktur in einer langen und komplexen Kette evolutionärer Transformationen ist daher unnötig, wenn nicht sogar irreführend. Wir empfehlen daher dringend, in zukünftigen Arbeiten den Begriff „tymbalian tymbal organ with a snapping mechanism“ zu verwenden. 2. Die Grundannahme von Davranoglou et al. (2019), dass – im Gegensatz zum neu entdeckten „snapping organ“ der Fulgoromorpha – allen Cicadomorpha ein „tymbal-ähnliches Or-gan“ gemeinsam sei, ist zu stark vereinfacht und vernachlässigt die enorme Vielfalt der Ausprägungen des Tymbals bei Nicht-Singzikaden innerhalb der Cicadomorpha. In Anbetracht der verfügbaren Studien scheint es daher zweifelhaft, dass sich die vibrationserzeugenden Strukturen dreimal unabhängig voneinander entwickelt haben sollen, wie es die phylogenetische Interpretation bei Davranoglou et al. (2019: Abb. 3) suggeriert

    The clinical significance of occult gastrointestinal primary tumours in metastatic cancer: A population retrospective cohort study

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    © 2018 by the Korean Cancer Association. Purpose The purpose of this study was to estimate the incidence of occult gastrointestinal (GI) primary tumours in patients with metastatic cancer of uncertain primary origin and evaluate their influence on treatments and overall survival (OS). Materials and Methods We used population heath data from Manitoba, Canada to identify all patients initially diagnosed with metastatic cancer between 2002 and 2011. We defined patients to have occult primary tumour if the primary was found at least 6 months after initial diagnosis. Otherwise, we considered primary tumours as obvious. We used propensity-score methods to match each patient with occult GI tumour to four patients with obvious GI tumour on all known clinicopathologic features. We compared treatments and 2-year survival data between the two patient groups and assessed treatment effect on OS using Cox regression adjustment. Results Eighty-three patients had occult GI primary tumours, accounting for 17.6% of men and 14% of women with metastatic cancer of uncertain primary. A 1:4 matching created a matched group of 332 patients with obvious GI primary tumour. Occult cases compared to the matched group were less likely to receive surgical interventions and targeted biological therapy, and more likely to receive cytotoxic empiric chemotherapeutic agents. Having an occult GI tumour was associated with reduced OS and appeared to be a nonsignificant independent predictor of OS when adjusting for treatment differences. Conclusion GI tumours are the most common occult primary tumours in men and the second most common in women. Patients with occult GI primary tumours are potentially being undertreated with available GI site-specific and targeted therapies

    Ears of the Armadillo: Global Health Research and Neglected Diseases in Texas

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    Neglected tropical diseases (NTDs) have\ud been recently identified as significant public\ud health problems in Texas and elsewhere in\ud the American South. A one-day forum on the\ud landscape of research and development and\ud the hidden burden of NTDs in Texas\ud explored the next steps to coordinate advocacy,\ud public health, and research into a\ud cogent health policy framework for the\ud American NTDs. It also highlighted how\ud U.S.-funded global health research can serve\ud to combat these health disparities in the\ud United States, in addition to benefiting\ud communities abroad

    Distraction test of the posterior superior iliac spine (PSIS) in the diagnosis of sacroiliac joint arthropathy

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    BACKGROUND: The sacroiliac joint (SIJ) is a frequently underestimated cause of lower back (LBP). A simple clinical test of sufficient validity would be desirable. The aim of this study was to evaluate the diagnostic value of a new PSIS distraction test for the clinical detection of SIJ arthropathy and to compare it to several commonly used clinical tests. METHODS: Consecutive patients, where a SIJ pathology had been confirmed by an SIJ infiltration were enrolled (case group, 61 SIJs in 46 patients). Before infiltration, patients were tested for pain with PSIS distraction by a punctual force on the PSIS in medial-to-lateral direction (PSIS distraction test), pain with pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber (or Patrick's) test. In addition, these clinical tests were applied to both SIJs of a population of individuals without history of LBP (control group, 64 SIJs in 32 patients). RESULTS: Within the investigated cohort, the PSIS distraction test showed a sensitivity of 100% and a specificity of 89% for SIJ pathology. The accuracy of the test was 94%, the positive predictive value (PPV) was 90% and the negative predictive value (NPV) was 100%. Pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber test were associated with a good specificity (> 90%) but a poor sensitivity (< 35%). CONCLUSIONS: Within our population of patients with confirmed SIJ arthropathy the PSIS distraction test was found to be of high sensitivity, specificity and accuracy. In contrast, common clinical tests showed a poor sensitivity. The PSIS distraction test seems to be an easy-to-perform and clinically valuable test for SIJ arthropathy
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