ABSTRACT
Thrombin is a serine protease that plays an essential role in blood coagulation and also induces various responses in endothelial cells. The actions of thrombin on the conversion of fibrinogen to fibrin are inhibited by peptides based on the amino acid sequence of hirudin, a natural anticoagulant from leeches. We show in these studies that the peptides Hir45-64 and sulfated Hir53-64 block the effects of thrombin on endothelial cells. These peptides inhibited, in a concentration-dependent manner, the synthesis of prostaglandin I2 and platelet-activating factor, and the acquisition of an adhesive surface for leukocytes that occur in response to thrombin. These actions of the peptides occurred even though the catalytic site of thrombin was not blocked.
Subject(s)
Endothelium, Vascular/physiology , Hirudins/analogs & derivatives , Hirudins/pharmacology , Peptide Fragments/pharmacology , Platelet Activating Factor/biosynthesis , Thrombin/pharmacology , Calcimycin/pharmacology , Cells, Cultured , Endothelium, Vascular/drug effects , Epoprostenol/biosynthesis , Humans , Inflammation , KineticsABSTRACT
Ureteroscopy has been used for the treatment of calculi throughout the ureter. The results of ureteroscopic stone removal were reviewed in 100 patients. Similar results were compared in 30 patients undergoing ureterolithotomy and 32 treated by basket manipulation. Success of ureteroscopic removal was related to the location of the calculus: 50 per cent in the proximal, 80 per cent in the mid and 99 per cent in the distal ureter. Hospital stay, costs and narcotic analgesic use were significantly less for ureteroscopic stone removal than for open surgical lithotomy. The success rate for ureteroscopic removal of distal calculi (99 per cent) was higher than for blind basketing procedures (59 per cent). Ureteroscopy should be considered the technique of choice for the removal of distal ureteral calculi. It is an acceptable alternative for treatment of calculi throughout the urinary tract.
Subject(s)
Endoscopy/methods , Ureteral Calculi/therapy , Adult , Aged , Analgesics, Opioid/therapeutic use , Costs and Cost Analysis , Cystoscopy , Female , Humans , Length of Stay , Male , Middle Aged , Pain, Postoperative/drug therapy , Ureteral Calculi/surgeryABSTRACT
Leukotriene B4 is the major biologically-active metabolite of arachidonate in stimulated neutrophils and previously has been shown to be a potent stimulus for neutrophil chemotaxis and aggregation. It is a less potent agonist for the secretion of granular contents from neutrophils. In the present study we have shown that leukotriene B4 does not activate all of the neutrophil responses seen with chemotactic peptides or the calcium ionophore A23187. This conclusion is based on the failure of exogenous leukotriene B4 to induce neutrophils to: (1) synthesize 5-hydroxyeicosatetraenoic acid or leukotriene B4 from endogenous arachidonate, (2) release arachidonate from membrane lipids, or (3) synthesize platelet-activating factor.
