482 research outputs found

    Natriuretic peptide receptors on rat thymocytes: Inhibition of proliferation by atrial natriuretic peptide.

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    Because the thymus expresses the natriuretic peptides (NP) as well as their respective receptors, an involvement of NP in the physiology of this organ has been suggested. To evaluate functional aspects of NP in the thymus, we looked for thymic cells bearing NP receptors (Npr). Furthermore, the regulation of Npr expression by activation of cells and the influence of NP on the proliferation of thymocytes was studied. Expression of receptor messenger RNAs CmRNAs) was examined by PCR and Northern blot. Existence of functional Npr was confirmed by measurement of cGMP, the second messenger of NP. Proliferation of thymocytes upon concanavalin A (Con A) stimulation was analyzed by incorporation of [“Hlthymidine. We report here that thymocytes express mRNAs for the three Npr, namely Npra, Nprb, and Nprc and that activation of Npra and Nprb increases cGMP levels. Stimulation of thymocytes with Con A (1 pg/ml, 48 h) resulted in an increase of mRNA coding for Npra, the receptor specific for atria1 natriuretic peptide (ANP) and brain natriuretic peptide. Nprb and Nprc receptor expression was not altered under these conditions. In agreement with these data only ANP, but not the C-type natriuretic peptide, elicited increased cGMP response in Con A-stimulated cells. ANP inhibited also the proliferation of Con A stimulated thymocytes, whereas C-type natriuretic peptide did not show this effect. These results suggest that ANP affects the complex mechanisms of thymocyte proliferation and differentiation

    Stress correlations of dislocations in a double-pileup configuration: a continuum dislocation density approach – complas XII

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    Dislocation motion in the crystal lattice of materials is the basis for macroscopic plasticity. While continuum models for describing the role of dislocations in plasticity have existed for decades, only recently have the mathematical tools become available to describe ensembles of moving, oriented lines. These tools have allowed for the creation of a Continuum Dislocation Dynamics (CDD) theory describing a second-order dislocation density tensor, a higher order analog of the classical dislocation density tensor, and its evolution in time. In order to reduce the computational complexity of the theory, a simplified theory has also been developed, which more readily allows for a numerical implementation, useful for describing larger systems of dislocations. In order to construct a self-consistent implementation, several issues have to be resolved including calculation of the stress field of a system of dislocations, coarse graining, and boundary values. The present work deals with the implementation including treatment of the near- and far-field stresses caused by the dislocation density tensor as well as boundary value considerations. The implementation is then applied to a few simple benchmark problems, notably the double pileup of dislocations in 1D. Applications to more general problems are considered, as well as comparisons with analytical solutions to classical dislocation problems. Focus is placed on problems where analytical solutions as well as simulations of discrete dislocations are known which act, along with experimental results, as the basis of comparison to determine the validity of the results

    Eutergesundheitsstatus von Milchkühen unterschiedlicher Rassen in der Frühlaktation

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    Milchkühe unterliegen in den ersten Wochen nach der Abkalbung, dem Zeitraum höchster Stoffwechselbelastung, einem besonderen Erkrankungsrisiko. Die Regelun¬gen des ökologischen Landbaus fordern die Wahl geeigneter standort¬angepasster Rassen, klare Empfehlungen existieren aber bisher nicht. Ziel der Untersuchung war ein Monitoring des Infektionsstatus von Tieren der Rasse Deutsche Holstein-Schwarzbunt (DH) und Deutschen Rotbunten im Doppelnutzungstyp (Rbt) unter gleichen Management¬bedingungen in den ersten 5 Wochen nach der Abkalbung. Weiterhin wurde untersucht, ob sich der Infektionsstatus von DH bei variierenden Management¬bedingungen unterschied. Die Ergebnisse zeigen eine höhere Infektionsrate für die Rbt. Die vorherrschenden Mastitiserreger in beiden Herden und bei beiden Rassen waren koagulase-negative Staphylokokken und die Hauptspezies S. chromogenes. Unter gleichen Managementbedingungen waren DH eutergesünder als Rbt

    Konversation und Geselligkeit

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    Based on the field of experience of ideality and reality, Karin Schulz develops a history of behavior diagnostics concerning French parlor conversation

    Impact of increasing morphological information by micro-CT scanning on the phylogenetic placement of Darwin wasps (Hymenoptera, Ichneumonidae) in amber.

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    The correct interpretation of fossils and their reliable taxonomic placements are fundamental for understanding the evolutionary history of biodiversity. Amber inclusions often preserve more morphological information than compression fossils, but are often partially hidden or distorted, which can impede taxonomic identification. Here, we studied four new fossil species of Darwin wasps from Baltic and Dominican amber, using micro computed tomography (micro-CT) scans and 3D reconstructions to accurately interpret and increase the availability of morphological information. We then infer their taxonomic placement in a Bayesian phylogenetic analysis by combining morphological and molecular data of extant and fossil Darwin wasps and evaluate the impact and usefulness of the additional information from micro-CT scanning. The results show that although we gained significant morphological information from micro-CT scanning, especially concerning measurements and hidden dorsal and ventral structures, this did not impact subfamily-level placement for any of the four fossils. However, micro-CT scanning improved the precision of fossil placements at the genus level, which might be key in future dating and diversification analyses. Finally, we describe the four new fossil species as Rhyssa gulliveri sp. nov. in Rhyssinae, Triclistus levii sp. nov. in Metopiinae, Firkantus freddykruegeri gen. et. sp. nov. in Pimplinae and Magnocula sarcophaga gen. et sp. nov. in Phygadeuontinae. The first two species are the first known representatives of the subfamilies Rhyssinae and Metopiinae in amber. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1186/s13358-023-00294-2

    Extended experience in parieto-occipital expansion surgery by meander technique—clinical and radiological evaluation

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    Introduction: Brachycephaly and anterior and posterior plagiocephaly appear as an isolated entity or manifest in syndromic conditions. In severe cases, possible treatment options currently comprise either cranioplasty or osteogenetic distraction. The aim of this paper is to retrospectively review the perioperative course of a series of children treated by posterior meander expansion technique at our institution with focus on the course of postoperative intracranial volume and eventual tonsillar descent evolution. Methods: Forty-two children received a posterior cranial vault remodeling by means of a posterior meander technique during a 7-year period. Hospital records were reviewed, and pre- and postoperative MRIs were analyzed for intracranial volume, cephalic and asymmetry index, and tonsillar position over time. Results: Median age at surgery was 11.5 months (range 17 days-10 years). Nineteen children had a symmetrical cranial deformity, twenty-three an asymmetrical synostosis. Half of the cohort showed a syndromic condition. Transfusions were administered in the majority (92.2%) of the cases. A significant postoperative increase of intracranial volume was present from 1188.9 ± 370.4 cm(3) to 1324.8 ± 352.9 cm(3) (p < 0.001). The asymmetry index showed a significant improvement postoperatively: 0.86 ± 0.06 versus 0.91 ± 0.05 (p < 0.001), while the cephalic index showed a non-statistical change (0.91 ± 0.11 versus 0.88 ± 0.08). Tonsillar herniation, bilateral or homolateral, showed no significant changes at early control, while a nonsignificant amelioration of tonsillar descent was seen among children older than 12 months at late imaging follow-up. Conclusion: Among the osteoplastic techniques, the posterior meander technique offers several advantages, such as early mobilization of the child, less bony defects, absence of implants, and a small complication rate. However, further comparative studies among different surgical techniques are needed

    Biparietal meander expansion technique for sagittal suture synostosis in patients older than 1 year of age—technical note

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    Objective: Sagittal suture synostosis (SSS) is the most common form of craniosynostosis. For older patients, the strategy for surgical correction needs to consider diminished growth dynamics of the skull and an active reconstruction cranioplasty aims to sustain stability for the active child. We describe our technique of biparietal meander expansion (BME) technique for SSS for patients older than 1 year and retrospectively reviewed the perioperative course as well as the subjective experience of patients and caregivers during follow-up. Methods: The BME technique incorporates bilateral serpentine craniotomies and fixation of the consecutively expanded bone tongues with crossing sutures for patients with SSS older than 12 months of age at surgery. We reviewed patients undergoing this surgical technique for correction of SSS and collected data about the clinical course and performed a patients reported outcome measure (PROM) for patients or caregivers to evaluate subjective experience and outcome after surgical treatment. Results: BME was performed in 31 patients (8 females; median age: 43 months; range 13-388). The mean length of operation was 172.7 ± 43 minutes (range 115-294). Patients experienced no immediate complications or neurological morbidity after surgery. Considering a total of 21 completed PROM questionnaires, the head shape after surgery was evaluated as either "better" (57%) or "much better" (43%) compared to preoperatively. Eighty-one percent of patients or caregivers answered that the patient experiences no limitation in daily activities. Although 42.8% perceived the hospital as strenuous, 90.5% would choose to undergo this treatment again. Conclusion: BME is a feasible technique for older SSS patients resulting in immediate stability of the remodelled calvarium with a more normal head shape. The survey among caregivers or patients revealed a favourable subjectively experienced outcome after this type of surgical treatment of SSS in the more complex context of an older patient cohort

    Eutergesundheits- und Stoffwechselstatus von Milchkühen in der Frühlaktation - was gibt den Ausschlag: Rasse oder Management?

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    Der Zeitraum der ansteigenden Milchleistung nach dem Kalben birgt ein höheres Risiko, dass die Tiere an Stoffwechselstörungen oder Mastitis erkranken. Die rechtlichen Regelungen für den ökologischen Landbau verschärfen dieses Risiko durch die Limitierung des Kraftfuttereinsatzes, fordern aber auch von den Landwirten mit Hilfe angepasster Rassen, dieses Problem anzugehen. Die vorliegende Studie zielte auf den Vergleich von zwei verschiedenen Rassen, die unter den gleichen Managementbedingungen gehalten wurden und einem Vergleich von zwei Betrieben, die zwar die gleiche Rasse hielten, sich aber im Management unterschieden. Es sollte geprüft werden ob die Rasse oder das Management entscheidender für den Eutergesundheits- und Stoffwechselstatus der Kühe in den ersten fünf Laktationswochen ist. Die Ergebnisse zeigten einen signifikanten Effekt der Energiebilanz und der Woche der Probenahme auf die getesteten Kriterien zur Einschätzung der Stoffwechselsituation (Fett-Eiweiß-Quotient FEQ, BHB-Konzentration der Milch, Glutamatdehydrogenase, nichtveresterte Fettsäuren). Hinsichtlich des FEQ und der BHB-Konzentration ergaben sich deutliche Effekte des Managements und der Rasse, wobei der managementeffekt deutlicher wurde. Der Zellgehalt des Gesamtgemelks zeigte Unterschiede zwischen den Herden, aber nicht zwischen den Rassen, die unter gleichen Bedingungen gehalten wurden
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