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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 56 (1991), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of adenosine on 45Ca2+ uptake by rat brain synaptosomes stimulated by electrical pulses was investigated. 45Ca2+ uptake was voltage dependent. Adenosine (1 μM-1 μM) decreased the uptake of 45Ca2+ induced by electrical stimulation (amplitude, 20 V; duration, 400 pμs; frequency, 10 pulses/s) in a concentration-dependent manner. At a concentration of 1 μM, adenosine almost abolished the 45Ca2+ uptake induced by electrical stimulation (92.9 ± 5.3% inhibition), but when the calcium uptake was induced by high-K+ (60 mM) medium, the effect of adenosine (1 μM) was smaller (43.8 ± 5.2% inhibition). The inhibitory effect of 1 μM adenosine on calcium uptake induced by electrical stimulation was antagonized by 1,3-dipropyl-8-p-sulfophenylxanthine (5 μM). The possibility that adenosine interacts with the calcium channels opened by electrical stimulation is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 19 (1972), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Two enzymes that selectively hydrolyse kinins at pH 7.5 were obtained in partially purified form from the supernatant fraction of homogenates of previously frozen rabbit brain by gel filtration on Sephadex G-100. The enzymes were detected and their activity estimated by bioassay with the isolated guinea pig ileum The products of the enzymic reactions were identified by high voltage electrophoresis at pH 3.5 and by the determination with the amino acid analyser of the amino acids released from the kinins.One enzyme, kinin-converting enzyme, catalyses the hydrolysis of kinin-10 (Lysbradykinin) and kinin-11 (Met-Lys-bradykinin) into kinin-9 (bradykinin). It also hydrolyses the aminoacyl-8-naphthylamides of methionine, lysine, arginine and leucine. The conversion of kinin-10 to kinin-9 was inhibited by puromycin (Ki 3.5 × 10−5 M) These properties are similar to those of brain arylamidases described in the literature.Kininase, the second enzyme, inactives kinins 9, 10 and 11 by peptide-bond hydrolysis. Similar rates of release of arginine and phenylalanine were observed for the three kinins, suggesting that kininase acts at the carboxy-terminus of these peptides.Our results suggest that brain contains proteases which apparently selectively metabolize polypeptide hormones that exert definite pharmacological effects on the central and peripheral nervous systems.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background  Evidence suggests that small airways contribute to clinically significant processes in asthma. Cysteinyl leukotrienes (CysLTs) are considered to be pivotal mediators in the pathogenesis of asthma. Montelukast (MK), a specific CysLT1 receptor antagonist, is metabolized in two main hydroxylated metabolites (termed M5 and M6, respectively).Objectives  The aims of this study were to compare the responsiveness of small and large human bronchi to the three CysLTs, to evaluate the antagonist activity of MK, M5 and M6 in these preparations of human bronchi, and to characterize the CysLT receptors involved in the contractile response.Methods and results  In isolated small bronchus (i.d. 0.5–2 mm), the potencies (−log molar EC50) of LTC4, LTD4 and LTE4 were 9.3 (n=11), 9.1 (n=30) and 8.4 (n=14), respectively. The three CysLTs were about 30-fold more potent in small bronchi than in larger bronchi (i.d. 4–6 mm). In small bronchi, MK significantly shifted to the right the CysLT concentration–effect curves with pA2 values against LTC4, LTD4 and LTE4 of 9.1 (n=3), 9.0 (n=11) and 8.7 (n=5), respectively. The antagonist potencies of M6 and M5 were similar to MK and fivefold lower, respectively. A similar activity of MK against the three CysLTs suggested that CysLT1 receptors are involved in the contraction of human bronchus. Analysis by RT-PCR also indicated that human bronchus mainly expressed CysLT1 receptors.Conclusion  MK exerts a potent antagonist activity against the particularly potent constricting effects of CysLTs in isolated human small bronchi, which only expressed the CysLT1 receptor subtype. The metabolites of MK are also potent in vitro antagonists, but may not participate in the therapeutic activity of MK due to their low plasma concentrations in patients treated with the recommended dose of MK.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Trypanosoma cruzi trypomastigotes treated with phosphatidylinositol-specific phospholipase C (PI-PLC) in vitro are rapidly induced to differentiate into round forms. Using confocal microscopy, we were able to show that trypomastigotes treated with PI-PLC initiate the process of flagellum remodeling by 30 sec after contact with the enzyme and amastigote-like forms are detected as early as 10 min after PI-PLC treatment. Scanning and transmission electron microscopy indicate that trypomastigotes undergo a previously undescribed process of flagellum circularization and internalization. Analysis of the flagellar complex with monoclonal antibody 4D9 shows heterogeneous labeling among the parasites, suggesting a remodeling of these molecules. After PI-PLC treatment, parasites rapidly lose the surface marker Ssp-3 and 24 h post-treatment they begin to exhibit a circular nucleus and a rod-shaped kinetoplast. By flow cytometry analysis and confocal microscopy, the Ssp-4 amastigote-specific epitope can be detected on the parasite surface. This indicates that the release of trypomastigote GPI-anchored molecules by exogenous PI-PLC in vitro can trigger morphological changes.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] (C57BLxBALB/c)Fx mice and nu/nu (athymic) mice of various genotypes were infected with 40 cercariae of S. mansoni on the shaved abdomen6. Schistosomules were prepared in vitro by mechanical agitation to cercariae in a Vortex mixer7, isolation of the cercarial bodies by layering the mixture of ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Theoretical Biology 163 (1993), S. 365-372 
    ISSN: 0022-5193
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0303-7207
    Keywords: Calcium binding ; Iodothyronine ; Thyroglobulin
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of some electrophysiological activities of the visual system (VERs) was compared in control rats and in young rats with poor intrauterine fetal growth caused by an electrolytic lesion of the placenta. Treated rats showed a delayed development of the electrophysiological functions considered, thus confirming the postnatal effect of poor intrauterine fetal growth.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1438-1435
    Keywords: Key words Gastrointestinal tract, perforation – Pneumoperitoneum – Helical computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To determine the value of helical CT in a consecutive series of elderly patients referred with clinically suspected gastrointestinal perforation. Methods: Our series comprised 34 consecutive elderly patients (mean age: 68 years) presenting with acute abdominal symptoms potentially suggestive of gastrointestinal perforation. All the patients were prospectively subjected to abdominal computed tomography (CT). On helical CT, the presence of free air was considered diagnostic of gastrointestinal perforation. Other findings such as intraperitoneal free fluid, thickening of bowel wall, streaky density within the mesentery, “dirty fat” sign, and focal collection of extraluminal fecal matter (“dirty mass”) were considered indirect findings of perforation. Results: At surgery, the following sites of perforation were found: duodenum (38.2 %), stomach (29.4 %), ileum (8.8 %), sigmoid colon (8.8 %), rectum (5.8 %), and jejunum, appendix, and transverse colon (2.9 % of cases each). CT demonstrated the presence of free air in 94.1 % of cases; intraperitoneal free fluid was present in 76.4 % of patients and thickening of bowel wall in 50 %. Streaky density within the mesentery was found in one patient. Conclusion: CT is a reliable diagnostic method by which to assess gastrointestinal perforation, because it provides excellent contrast resolution to depict the presence of even small amounts of free air in the abdomen. This is particularly helpful where elderly patients are concerned.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Emergency radiology 7 (2000), S. 263-267 
    ISSN: 1438-1435
    Keywords: Key words Gastrointestinal tract, perforation – Pneumoperitoneum – Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To investigate the spectrum of US findings as encountered in a consecutive series of patients referred with clinically suspected gastrointestinal perforation. Methods: Seventy-two consecutive patients (mean age: 42.9 years) with clinically suspected gastrointestinal perforation were prospectively examined with abdominal ultrasound (US). The US examinations were all performed by a certified senior radiologist, who was blind to other imaging findings. Patients were screened for the presence of free intraperitoneal gas (characteristic comet-tail artifacts, ring-down artifacts, and the “shifting phenomenon” were our diagnostic indicators of pneumoperitoneum). Other signs potentially suggestive of gastrointestinal perforation were also looked for, including free intraperitoneal fluid, thickening of bowel walls, gallbladder walls, gastric walls, or duodenal walls, or local peritoneal inflammation. Patients with equivocal or inconclusive findings on US were submitted to abdominal computed tomography (CT) 10–15 min after US examinations. Results: Of the 72 patients prospectively examined by US, 63 (87.5 %) underwent subsequent emergent surgery within next 2 days. A gastrointestinal perforation was found in all the 63 patients referred for operative treatment: overall, 41 gastroduodenal and 22 intestinal perforations were found. On US, in the 41 patients with surgically proven gastroduodenal perforation, the most common finding was free intraperitoneal gas (28/41, 68.3 %). The 13/41 patients (31.7 %) without evidence of free gas on US underwent preoperative abdominal CT assessment, which allowed the correct diagnosis of gastroduodenal perforation in 12/13 cases. In the 22 patients with surgically proven intestinal perforation the most common finding detected on US was free intraperitoneal fluid (14/22, 63.6 %); sonographic evidence of free intraperitoneal gas was seen in only 8/22 patients (36.4 %). The 14/22 patients (63.6 %) without free gas on US underwent preoperative abdominal CT assessment, which allowed the diagnosis of intestinal perforation in 12/14 cases. Conclusion: US examinations allow very rapid screening of patients referred with clinically suspected gastrointestinal perforation and for triage of patients who are to undergo more invasive imaging tests.
    Type of Medium: Electronic Resource
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