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At least 829 records · Page 46Linked to original sources
PubMed2004

An evaluation of colorectal endoscopic mucosal resection using high-magnification chromoscopic colonoscopy: a prospective study of 1000 colonoscopies.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection provides an alternative to surgery for resection of sessile and flat colorectal lesions. High-magnification chromoscopic colonoscopy may allow early detection and anticipate histological diagnosis by identifying colonic crypt patterns. The aim of the present study was to assess the efficacy and safety of en-bloc endoscopic mucosal resection with high-magnification chromoendoscopy in the management of sessile and flat colorectal lesions </= 20 mm. PATIENTS AND METHODS: A single endoscopist using high-magnification chromoendoscopy prospectively examined 1000 patients attending for routine colonoscopy. Patients were selected for inclusion in the study if they were considered to be at high risk for underlying colorectal neoplasia or polyps. Within the study period, 1000 patients (29 %) qualified for entry from a total of 3480 colonoscopies conducted in our institution. Endoscopic mucosal resection was carried out in appropriate flat and sessile lesions. RESULTS: Endoscopic mucosal resection was carried out in 599 lesions. Complete histological resection was confirmed in 576 (96 %). Perforation occurred in one patient (0.2 %) and bleeding in 12 (2 %). A total of 254 lesions (40 %; excluding hyperplasia/metaplasia) were flat or depressed, and 374 (60 %) were sessile. Fifty-eight flat lesions (23 %) contained high-grade dysplasia or beyond, compared to 33 sessile lesions (9.0 %; P = 0.001). After resection, 21 lesions were upgraded histologically, with 17 being defined as adenoma with high-grade dysplasia or beyond. CONCLUSIONS: This study confirms that flat adenomas and carcinomas occur in the West and demonstrates the malignant potential of such lesions, which can be managed successfully using endoscopic techniques. Endoscopic mucosal resection with high-magnification chromoscopy is a safe and effective form of treatment for sessile or flat colorectal lesions. Complete resection can improve the accuracy of histopathological diagnosis. However, colonoscopists require training in these procedures in order to improve the rate of colorectal cancer detection.

Adenoma↗
PubMed1991

6-Pentadecylsalicylic acid: an antithrombin component isolated from the stem of Rhus semialata var. roxburghii.

Bioassay-directed fractionation of the n-hexane extract of the stem of Rhus semialata Murr. var. roxburghii DC (Anacardiaceae) has led to the isolation of 6-pentadecylsalicylic acid. It showed antithrombin activity at 50 micrograms/ml in the amidolytic method. It also prolonged the clotting time in a dose-dependent manner in the clotting assay of thrombin-fibrinogen interaction.

Amino Acid Sequence↗
PubMed1994

Plasma thrombin neutralization assay: pharmacokinetic applications.

UFH and its derivatives, LMWHs, are effective and safe in the prevention and treatment of DVT. The mechanism for this effectiveness has been difficult to explain, given that the anti-IIa activity of LMWHs is important for their antithrombotic activity and the reported half-life of the anti-IIa activity of LMWHs is very short. The standard chromogenic anti-IIa assay is performed in an artificial system consisting of highly diluted plasma to which antithrombin III is added. It is possible, therefore, that the apparently short half-life of the anti-IIa activity is dependent on the limitations of the anti-IIa assay, commonly used in the pharmacokinetic studies. We have developed an anti-IIa assay that is more sensitive than the standard one. Our assay is based on the ability of UFH or LMWHs to catalyze the formation of TAT complexes. PTNA was able to detect in vitro the anti-IIa activity produced by 0.01 anti-Xa IU/mL of UFH or 0.05 anti-Xa IU/mL of LMWHs. Ex vivo, it was able to describe the time course of plasma anti-IIa activity of very low doses of UFH (intravenous or subcutaneous) or LMWHs. To characterize better the role of the anti-IIa activity of LMWHs, the pharmacokinetic properties of two of these agents have been evaluated in humans, assessing the anti-IIa activity by PTNA. Fraxiparine, 7500 and 10,000 ICU, and Enoxaparine, 20 and 40 mg, were administered subcutaneously to six healthy volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Coacute heparin: a new simple monotest for monitoring heparin treatment.

Anti-Factor Xa methods have been generally accepted for the monitoring of heparin treatment, mainly due to their sensitivity to LMW heparin and excellent performance on automated equipment. When such equipment is not available, as in small laboratories or on the night shift, there is a need for a simple manual method. In the present method activated Factor X and a chromogenic peptide substrate are colyophilized in plastic cuvettes under conditions that avoid reaction between the two constituents. The assay is performed accordingly: Plasma (200 microL) is diluted in 3.0 mL predispensed Tris buffer containing dextran sulfate 8000 to avoid losses of heparin due to, for example, platelet factor 4. The diluted plasma (400 microL) is added to a cuvette. The reagents are rapidly dissolved and the reactions start. The rate of Factor Xa inhibition is proportional to the heparin activity. During the incubation, the substrate is also hydrolyzed by the remaining enzyme. This combination of reactions is insensitive to changes in temperature, making it possible to perform the assay at room temperature. After 10 minutes incubation, the reaction is stopped by adding 400 microL of 5% acetic acid. The absorbance is read in a well-calibrated photometer and the results plotted on a graph available in the kit. Eleven commercially available heparins have been tested with the assay and they all fell within a narrow range, showing the relevance of using a standard plot for all heparins. The LMW heparins behaved differently and it may also be that they demand different therapeutic strategies.

Antithrombins↗
PubMed1983

[Use of chromogenic substrate in cerebrospinal fluid diagnosis].

Amidolytic assays with chromogenic substrates exhibit great sensitivity, easy management, and good reproducibility. Consequently, they can be used with advantage in the analysis of cerebrospinal fluid (CSF). CSF levels of alpha 2-macroglobulin, alpha 1-antitrypsin, and plasminogen can thus be determined without a concentration step prior to analysis--lowered alpha 1-antitrypsin levels included. Serum/CSF concentration ratios obtained with these assays agree well with data calculated from immunochemical procedures. Moreover, there was a good correlation between amidolytic and immunochemical procedures. These reflections make it apparent that they can be adapted for routine evaluation of the above mentioned parameters.

Cerebrospinal Fluid Proteins↗
PubMed1991

Epidermal growth factor and 12-tetradecanoyl phorbol 13-acetate induction of urokinase in A431 cells.

The signal transduction pathways of urokinase (u-PA) in A431 cells, a human epidermoid carcinoma cell line, were studied using the inducers EGF and TPA. Based on the following observations, we conclude that the two pathways are different: (1) The effects are additive; (2) EGF induction of u-PA was not compromised either by down-regulation of PKC or selective inhibition of the same by H7; (3) 8-Br-cAMP has no effect by itself; however, it inhibits the EGF effect and doubles the TPA induction of u-PA; (4) after EGF-induced tyrosine phosphorylations are completed, addition of TPA can still induce u-PA, an effect that can be blocked by the addition of the tyrosine phosphorylation inhibitor, genistein, indicating that the two agents induce different tyrosine phosphorylation; (5) in 2-dimensional electrophoresis of 32P-labeled cell lysates, inducer-specific differences in the intensity of spots can be observed. Some of the spots weakened by genistein (tyrosine phosphorylations) are different, depending on the inducer used.

Chromogenic Compounds↗
PubMed1980

[The determination of inhibitors of haemostasis using chromogenic substances (author's transl)].

Heparin like activity, antithrombin III and antiplasmin were determined in the plasma of 31 healthy adults and the umbilical vein of 33 newborns after delivery. Inhibitor activities were significantly decreased in umbilical venous blood. Methodological experiments are described showing the good reproducability of determinations with chromogenic substrates. The measured activities are no different in fresh or frozen plasma. The clinical relevance of inhibitor determinations is discussed.

Adult↗