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41.
Standard approach to membrane transport generated by osmotic andhydrostatic pressures, developed by Kedem and Katchalsky, is based onprinciples of thermodynamics of irreversible processes. In this paper wepropose an alternative technique. We derive transport equations from fewfairly natural assumptions and a mechanistic interpretation of the flows.In particular we postulate that a sieve-type membrane permeability isdetermined by the pore sizes and these are random within certain range.Assuming that an individual pore is either permeable or impermeable tosolute molecules, the membrane reflection coefficient depends on the ratioof permeable and impermeable pores. Considering flows through permeableand impermeable pores separately, we derive equations for the total volumeflux, solute flux and the solvent flux across the membrane. Comparing themechanistic equations to the Kedem-Katchalsky equations we find the formereasier to interpret physically. Based on the mechanistic equations we alsoderive a correlation relation for the membrane transport parameters L
p,, and . This relation eliminates the need for experimentaldetermination of all three phenomenological parameters, which in somecases met with considerable difficulties. 相似文献
42.
Rütgen BC Willenbrock S Reimann-Berg N Walter I Fuchs-Baumgartinger A Wagner S Kovacic B Essler SE Schwendenwein I Nolte I Saalmüller A Murua Escobar H 《PloS one》2012,7(6):e40078
Cell lines are key tools in cancer research allowing the generation of neoplasias in animal models resembling the initial tumours able to mimic the original neoplasias closely in vivo. Canine lymphoma is the major hematopoietic malignancy in dogs and considered as a valuable spontaneous large animal model for human Non-Hodgkin's Lymphoma (NHL). Herein we describe the establishment and characterisation of an in vivo model using the canine B-cell lymphoma cell line CLBL-1 analysing the stability of the induced tumours and the ability to resemble the original material. CLBL-1 was injected into Rag2(-/-)γ(c) (-/-) mice. The generated tumor material was analysed by immunophenotyping and histopathology and used to establish the cell line CLBL-1M. Both cell lines were karyotyped for detection of chromosomal aberrations. Additionally, CLBL-1 was stimulated with IL-2 and DSP30 as described for primary canine B-cell lymphomas and NHL to examine the stimulatory effect on cell proliferation. CLBL-1 in vivo application resulted in lymphoma-like disease and tumor formation. Immunophenotypic analysis of tumorous material showed expression of CD45(+), MHCII(+), CD11a(+) and CD79αcy(+). PARR analysis showed positivity for IgH indicating a monoclonal character. These cytogenetic, molecular, immunophenotypical and histological characterisations of the in vivo model reveal that the induced tumours and thereof generated cell line resemble closely the original material. After DSP30 and IL-2 stimulation, CLBL-1 showed to respond in the same way as primary material. The herein described CLBL-1 in vivo model provides a highly stable tool for B-cell lymphoma research in veterinary and human medicine allowing various further in vivo studies. 相似文献
43.
C Couturier A Bauer A Rey C Schroif-Dufour M Broenstrup 《Bioorganic & medicinal chemistry letters》2012,22(19):6292-6296
Armeniaspiroles, a novel class of natural products isolated from Streptomyces armeniacus, are characterized by a novel spiro[4.4]non-8-ene scaffold. Various derivatives of Armeniaspiroles could be obtained by halogenation, alkylation, addition/elimination or reductions. A total synthesis of the 5-chloro analog of Armeniaspirole A has been accomplished in a linear six-step sequence. 5-Chloro-Armeniaspirole A exhibits good activity against a range of multidrug-resistant, Gram-positive bacterial pathogens. 相似文献
44.
Salman Can Adam Fiolka Dirk Wilhelm Maria Burian Stefan von Delius Alexander Meining Armin Schneider Hubertus Feussner 《Biomedizinische Technik》2008,53(4):185-189
Abstract One of the current main challenges in transluminal surgery is in obtaining sterile and secure access to the peritoneal cavity. Since the transgastric approach has not fulfilled these requirements up to now, a new transcolonic surgical approach was developed to achieve these objectives and enhance the potential of transluminal surgery. A new set of instruments comprising an endoscopic trocar, a flexible obturator and a modified transanal endoscopic microsurgery device was designed to permit sterile sigmoid access for transcolonic surgery. The set of instruments has already been successfully tested in an experimental in vivo survival study that confirmed safety and sterility as objectives during surgical intervention. The suitability of the instruments for use in the human anatomy was confirmed by a cadaveric study. 相似文献
45.
Since its discovery 10 years ago the histamine H(4) receptor (H(4)R) has attracted attention as a potential drug target, for instance, for the treatment of inflammatory and allergic diseases. Potent and selective ligands including agonists are required as pharmacological tools to study the role of the H(4)R in vitro and in vivo. Many H(4)R agonists, which were identified among already known histamine receptor ligands, show only low or insufficient H(4)R selectivity. In addition, the investigation of numerous H(4)R agonists in animal models is hampered by species-dependent discrepancies regarding potencies and histamine receptor selectivities of the available compounds, especially when comparing human and rodent receptors. This article gives an overview about structures, potencies, and selectivities of various compounds showing H(4)R agonistic activity and summarizes the structure-activity relationships of selected compound classes. 相似文献
46.
47.
Armin J. Hinterwirth Thomas L. Daniel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2010,196(12):947-956
Flying insects rely on the integration of feedback signals from multiple sensory modalities. Thus, in addition to the visual
input, mechanosensory information from antennae is crucial for stable flight in the hawkmoth Manduca sexta. However, the nature of compensatory reflexes mediated by mechanoreceptors on the antennae is unknown. In this study we describe
an abdominal flexion response mediated by the antennal mechanosensory input during mechanical body rotations. Such reflexive
abdominal motions lead to shifts in the animal’s center of mass, and therefore changes in flight trajectory. Moths respond
with abdominal flexion both to visual and mechanical rotations, but the mechanical response depends on the presence of the
mass of the flagellum. In addition, the mechanically mediated flexion response is about 200° out of phase with the visual
response and adds linearly to it. Phase-shifting feedback signals in such a manner can lead to a more stable behavioral output
response when the animal is faced with turbulent perturbations to the flight path. 相似文献
48.
Nazaré M Matter H Klingler O Al-Obeidi F Schreuder H Zoller G Czech J Lorenz M Dudda A Peyman A Nestler HP Urmann M Bauer A Laux V Wehner V Will DW 《Bioorganic & medicinal chemistry letters》2004,14(11):2801-2805
A series of novel, highly potent, achiral factor Xa inhibitors based on a benzoic acid scaffold and containing a chlorophenethyl moiety directed towards the protease S1 pocket is described. A number of structural features, such as the requirements of the P1, P4 and ester-binding pocket ligands were explored with respect to inhibition of factor Xa. Compound 46 was found to be the most potent compound in a series of antithrombotic secondary assays. 相似文献
49.
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