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排序方式: 共有204条查询结果,搜索用时 15 毫秒
51.
Conditions were defined for the derivatization of recombinant tissue plasminogen activator (rt-PA) with polyethylene glycol (PEG) so as to retain functional activity as a possible means of producing a t-PA species with a prolonged circulating lifetime. Derivatives with a wide range of retention of activities were prepared by varying the concentration and species of activated PEG. The specific activities of the PEG-rt-PA derivatives were dependent on the method of assay. Assays using preformed fibrin gave higher estimates of retention of activity than assays using soluble components. Plasma elimination studies in mice and rats indicated prolonged circulating lifetimes for the radiolabeled PEG-rt-PA derivatives after a rapid clearance and distribution phase; however, the disappearance of functional activity was much more rapid than the disappearance of radiolabeled material. The PEG-rt-PA derivatives appeared to accumulate in tissues above their interstitial fluid concentrations and were rapidly inactivated, apparently by reaction with the plasma protease inhibitors. These results were consistent with the inactivation of the PEG-rt-PA derivatives in rat plasma in vitro. A somewhat longer half-life (t1/2) of the one derivative studied was observed in dogs (t1/2, 16 minutes) as compared with the rat (t1/2, five minutes). This was sufficient to confer thrombolytic activity upon the derivative (administered by bolus injection) in contrast to native rt-PA. The potential of PEG-modified rt-PA as a long-lived thrombolytic agent in humans will depend, however, on whether there will be a further extension of the t1/2 because of a reduction in clearance and/or a reduction in the rate of inactivation. 相似文献
52.
The role of endothelium in the inhibition of human factor Xa was studied in a plasma environment. Human factor Xa can bind to and function on bovine aortic endothelium in a manner similar to that of bovine factor Xa. Approximately 70% of the bound factor Xa is subject to inhibition by plasma proteinase inhibitors, and the remaining 30% is irreversibly bound as part of a 125 Kd membrane-associated complex not subject to proteolytic degradation. The proportion reversibly bound and its rate of release do not alter with changes in calcium, citrate, heparin, or active proteinase inhibitor concentrations. The principal plasma proteinase inhibitor of human factor Xa was antithrombin III, which accounted for 60% to 65% of factor Xa released from endothelium, with alpha 1-proteinase inhibitor inactivating 20% to 25% and alpha 2- macroglobulin approximately 15%. All of the reversibly bound factor Xa was identified in complex with one of these three proteinase inhibitors. The thrombin active-site inhibitor hirudin was found to markedly accelerate the displacement of reversibly bound factor Xa from the endothelium and to associate specifically with factor Xa without a loss of activity toward chromogenic substrates, perhaps accounting for a novel mechanism of anticoagulation. 相似文献
53.
Electron microscopic localization of factor-VIII-related antigen in adult human blood vessels 总被引:6,自引:0,他引:6
We have localized factor-VIII-related antigen, using immunofluorescence and electron microscopy, in adult human blood vessels. In addition to its presence in endothelial cells, the antigen was localized within subendothelium and the layers of elastic lamina closest to the lumen. Also, we provide the first morphological evidence that factor-VIII- related antigen is associated with collagen fibrils within the vessel wall. These studies suggest that this subendothelial factor-VIII- related antigen may play a role in the adhesion of platelets to subendothelial components following endothelial injury. 相似文献
54.
Background
Imprisonment may lead to the development of mental illness, especially depression. This study examines the clinical and sociodemographic profiles of imprisoned women, identifies indicative signs of depression, and relates these indicators to other variables. 相似文献55.
56.
HERDIS MOLINDER MARI ANN WALLANDER KURT SVÄRDSUDD GÖRAN BODEMAR 《Scandinavian journal of gastroenterology》2013,48(3):224-230
To evaluate the therapeutic potential of the newly developed proton pump inhibitor lansoprazole in patients with reflux oesophagitis, we performed a double-blind randomized clinical trial comparing 20 mg omeprazole and 30 mg lansoprazole, involving 229 patients at 9 Scandinavian hospitals. The treatment period was 4 or 8 weeks, and main efficacy variables were healing of endoscopic changes, relief of reflux symptoms, and occurrence of adverse events. No significant difference in terms of healing was found, either after 4 or after 8 weeks' treatment. Patients receiving lansoprazole experienced a greater improvement in heartburn after 4 weeks (p = 0.03), and there was a similar trend for acid regurgitation. Lansoprazole was found to be an effective and safe alternative to omeprazole in short-term treatment of moderate reflux oesophagitis. 相似文献
57.
Yu. N. Takhauova V. S. Skuridin B. K. Kudelin V. M. Golovkov N. V. Varlamova E. V. Makarova V. I. Chernov 《Pharmaceutical Chemistry Journal》2009,43(9):521-524
Experimental batches of iodine-123-labeled beta-methyl iodophenylpentadecanoic acid (123I-BMIPP) with an activity of 180 MBq/mL have been produced based on 123I extracted from enriched 122Te targets irradiated by accelerated deuterons at the R-7M cyclotron. It is shown that the radiochemical purity of 123I-BMIPP in EtOH solutions exceeds 96% at an acceptable content of the main chemical impurities (Cu, Te). The conditions of
123I-BMIPP dilution in human serum albumin (10%) solution for injection in experimental animals are determined. The biological
behavior of the preparation in rats has been studied. It is established that 123I-BMIPP is characterized by pronounced accumulation in the heart. A qualitative scintigram of the rabbit heart was obtained
and showed the possibility of external detection. It is established that it is possible to judge the viability of myocardium
by measuring the amount of 123I-BMIPP accumulated in the heart. 相似文献
58.
S Singh SV Gibikote S Sen A Korula IP Korah 《Journal of Medical Imaging and Radiation Oncology》1999,43(4):539-541
A case of hydatid disease of the lung proven by thoracotomy and histopathological evaluation is described. It was clinically and radiologically suggestive of a complicated pulmonary sequestration or non-resolving consolidation. 相似文献
59.
The present study has analysed the DNA adducts formed in SENCAR mouse
epidermis following topical application of 7-methylbenz[a]anthracene (7-
MBA). Mice were treated with 400 nmol of 7-MBA, which represents an
initiating dose of this hydrocarbon for SENCAR mice. DNA adducts were
analysed 24 h after topical application of the hydrocarbon by 32P-
postlabeling coupled with either HPLC analysis or an improved TLC procedure
giving better resolution of DNA adducts through the use of a D6 solvent
[isopropanol:4N NH4OH (1:1)] following D5. Twenty-four hours after topical
application of 400 nmol 7-MBA, the level of total covalent binding was 0.37
+/- 0.07 pmol/mg DNA as determined by 32P- postlabeling. This level of
binding correlated well with the relative tumor initiating activity of this
hydrocarbon compared to 7,12- dimethylbenz[a]anthracene (6.4 +/- 0.01
pmol/mg DNA) and dibenz[a,j]anthracene (0.03 +/- 0.01 pmol/mg DNA).
Analysis of the 32P- labeled 3',5'-diphosphodeoxyribonucleosides by HPLC
and TLC revealed the presence of deoxyguanosine (dGuo) and deoxyadenosine
(dAdo) adducts formed from both the anti- and syn-bay-region diol-epoxides
of 7-MBA (anti- and syn-7-MBADEs). The major DNA adduct derived from 7-MBA
in mouse epidermis was tentatively identified as (+) anti-7-MBADE-trans-N2-
dGuo. In addition, a minor dGuo adduct derived from the bay-region syn-
diol-epoxide of 7-MBA was detected as well as a minor dAdo adduct from this
diol-epoxide. Another minor dAdo adduct was also detectably present which
arose from either the anti- or syn-diol epoxide. Furthermore, several
unidentified DNA adducts were present in both HPLC and TLC chromatograms of
DNA samples from 7-MBA-treated mice. These results are discussed in terms
of the role of specific 7-MBA-DNA adducts in tumor initiation by this
hydrocarbon.
相似文献
60.
A N Britov G S Zhukovski? V G Sviderski? T A Varlamova L V Liubimova V V Naumova A D Deev V N Spizhovy? B I Adon'ev E A Grishenko 《Kardiologiia》1992,32(7-8):68-73
A programme on supplementary health education of medical staff from city polyclinics in the prevention and treatment of arterial hypertension was launched in one of the Moscow districts for 3 years. Another district was used as a comparison subject. Representative samples of residents aged 35-64 years from the two districts were screened before and after implementation of the programme. The WHO International MONICA programme was used to evaluate the efficiency of the programme proposed by the authors. The intervention district showed an improvement of hypertensives' awareness of the disease and a double increase in the number of patients with a high compliance. In the comparison district, these parameters remained unchanged. According to the criteria developed in the MONICA programme, there was a downward tendency in the incidence of myocardial infarction and stroke and these diseases-related deaths in the intervention district, whereas this was not observed in the district under comparison. 相似文献