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Biomedical subjects

B R Binder

Publications and source records attributed to B R Binder.

215 records · Page 12Linked to original sources
PubMed1983

Effects of antiproteases (aprotinin and gabexate-mesilate) on the postischemic vascular response of the kidney.

Both under physiologic conditions and after short-term ischemia (1-3 min) kallikrein and locally synthesized prostaglandins contribute to control renal blood flow. In the present experiment the antiproteases aprotinin and gabexate-mesilate were administered to rabbits in an attempt to show whether the hemodynamic changes produced by 60 min of normothermic ischemia, i.e., postischemic hyperemia and reduction of vascular resistance, were equally mediated by kallikrein. Vascular responses were evaluated by determining renal cortical blood flow using radioactively labelled microspheres, by calculating vascular resistances, and by measuring the diameters of renal medullary vessles. Kidneys exposed to normothermic ischemia and sham-operated control organs of animals treated with aprotinin (2 X 40,000 KIU/kg body weight) and gabexate-mesilate (2 X 7 mg/kg body weight) were compared with those of rabbits which were analogously operated, but did not receive any drugs. As the antiproteases used did not significantly affect the hyperemia and the reduction of renal cortical vascular resistance seen after 60 min of normothermic ischemia, these phenomena are apparently not mediated by kallikrein. Renal medullary vasodilatation (arteriolae rectae) was significantly lower under aprotinin than in untreated ischemic kidneys, and was not longer demonstrable in gabexate-mesilate-treated animals. Thus, the effect of gabexate-mesilate was superior to that of aprotinin. Whether the antiprotease action is due to an unspecific membrane-stabilizing, to a general enzyme-inhibiting, or to a specific kallikrein-inhibiting effect, is still unclear.

Animals↗
PubMed1983

Effects of external renal hypothermia on postischemic hemodynamics.

In the rabbit model renal cortical blood flow after 60 min of normothermic ischemia is seen to rise significantly in the early reperfusion period. Under otherwise identical conditions this phenomenon is absent after hypothermic ischemia produced by surface cooling of the kidney and in sham-operated kidneys. It is still unclear whether postischemic hyperemia is a physiologic counterregulatory mechanism in response to 60-min normothermic ischemia of the rabbit kidney or a contributory factor in the development of acute postischemic renal failure.

Acute Kidney Injury↗
PubMed1983

Renal blood flow alterations after temporary ischemia. An experimental model in the rabbit.

In an effort to investigate the efficiency of various pharmacological agents in protecting the kidney against normothermic ischemia, an animal model was developed and the post-ischemic hemodynamics in the renal cortex of rabbit kidneys were studied. Renal cortical blood flow was evaluated 5-30 min after 60 min of normothermic ischemia of the left kidney using 141Ce-, 51Cr-, and 85Sr-labelled microspheres. Control groups were subjected to sham operation. The right kidneys served as individual controls. Ischemic kidneys showed a significant weight increase independent of reperfusion. Furthermore, a transient highly significant increase of cortical blood flow was found with an absolute maximum about 10 min after termination of ischemia. This increase in cortical blood flow was paralleled by a highly significant decrease of vascular resistance.

Animals↗
PubMed1982

Rapid isolation of high molecular weight urokinase from native human urine.

Urokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

Centrifugation, Density Gradient↗
PubMed1982

Plasminogen activator activity in the aorta of strains of rats with genetically determined different patterns of lipids in the blood. Induction of increased activity by streptozotocin.

In a strain of genetically hypercholesterolemic rats (RICO), developed from an albino mutant of Rattus norvegicus (Sprague-Dawley, Tif: RAIf, SPF) by selective breeding, the intimal plasminogen activator activity (PAA) at the nonbranching regions of the aorta was markedly lower than at the nonbranching regions of the aorta in the control strain (Sprague-Dawley). At the branching regions of the aorta the intimal PAA showed no difference between the two strains of rats. In another strain of rats (HBC; hyper-beta-cholesterolemic) with a slightly elevated level of total cholesterol in the blood, a high concentration of LDL-cholesterol and a low concentration of triglycerides, the intimal PAA showed no difference from that in the control strain (Sprague-Dawley) at the branching and nonbranching regions of the aorta. 6 weeks after a single injection of streptozotocin at a diabetogenic dose (45 mg/kg) into RICO rats and the control strain, the intimal PAA was found to be increased by 280% in RICO rats, but only by 140% in controls, compared to that in the corresponding nontreated rats.

Animals↗
PubMed1981

The effect of hemorrhagic hypotension on urinary kallikrein excretion, renin activity, and renal cortical blood flow in the pig.

We measured urinary kallikrein by its esterolytic and kinin-forming activity in 5-minute urine samples obtained throughout continuous bleeding experiments in pigs to correlate possible changes in urinary kallikrein excretion during hemorrhagic hypotension with resin activity and renal cortical blood flow. Renin activity was determined in venous blood samples and renal cortical blood flow was estimated by the radiolabeled microsphere technique. The rate of urinary kallikrein excretion was increased about 4-fold within an arterial pressure range of 100-70 mm Hg, whereas below 70 mm Hg, arterial pressure urinary kallikrein activity declined to undetectable values. Renin activity was increased only 2-fold in the arterial pressure range between 100 and 70 mm Hg but was increased 4-fold at pressures below 70 mm Hg. The pressure range of 100 to 70 mm Hg corresponded to the autoregulation of renal cortical blood flow and glomerular filtration rate; below that pressure range, renal cortical blood flow dropped to about 10% of the initial value. Therefore, it seems that urinary kallikrein is activated mainly during the period of autoregulation, whereas renin activity is, in the main, increased below the autoregulatory range of pressure. The vasodilatory urinary kallikrein kinin system might be involved in maintaining sufficient local blood flow during autoregulation whereas a decrease in blood pressure below the autoregulatory range leads to a major increase in renin activity, thus illustrating the attempt of the organism to reestablish sufficient blood pressure to maintain autoregulation.

Animals↗
PubMed1981

Application of hydrophobic interaction chromatography for purification of pig urinary kallikrein. Characterization of the enzyme and its antibody.

Pig urinary kallikrein was purified following its kinin-generating activity as well as its esterase activity on N alpha-benzoyl-L-arginine ethyl ether (BZArgOEt). The isolation procedure, based on hydrophobic interaction chromatography on octyl-Sepharose and affinity chromatography on aprotinin-Sepharose resulted in a 2 500- to 3 000-fold purified enzyme with a yield of 6%. The preparation was homogenous on alkaline polyacrylamide disc gel electrophoresis and exhibited a single polypeptide chain in dodecyl sulfate-polyacrylamide gel electrophoresis upon reduction and alkylation corresponding to a molecular weight of 47 000. Isoelectric focusing in flat bed polyacrylamide gels revealed one stained band and one coinciding symmetrical peak of activities which could be eluted between pH 3.6 and pH 4.1 from a replica gel. Monospecific antibodies could be raised in a rabbit and kinetic studies for kinin-generating activity and esterolytic activity (substrate BZArgOEt) of the enzyme as well as for antibody-induced inhibition of the enzyme were performed. The antibody inhibited the antigen via a competitive mechanism near or at the active site of the enzyme.

Animals↗
PubMedDate not supplied

Stimulation of tissue factor expression in human microvascular and macrovascular endothelial cells by cultured vascular smooth muscle cells in vitro.

The effect of conditioned media obtained from different smooth muscle cells (SMC) on tissue factor (TF) expression in endothelial cells (EC) in vitro was investigated. We could show that conditioned media from cultured human aortic SMC, human umbilical artery SMC or human umbilical vein SMC all resembling the synthetic phenotype of SMC induced TF activity in human umbilical vein EC and human skin microvascular EC in a dose- and time-dependent fashion. This induction was also seen at the level of specific TF mRNA as evidenced by Northern blotting. The TF inducing activity was heat-labile and acid-stable and had an approximate molecular mass of 38 kD. This activity was found to be distinct from known inducers of TF expression in EC such as interleukin-1, tumor necrosis factor-alpha, bacterial lipopolysaccharide or vascular endothelial growth factor. Such as factor, if released by SMC in vivo, could contribute to the activation of EC under conditions such as when EC are in close contact with SMC of the synthetic (nondifferentiated) phenotype seen in processes like vessel development or neo-intima formation.

Aorta↗
PubMedDate not supplied

Anisodamine counteracts lipopolysaccharide-induced tissue factor and plasminogen activator inhibitor-1 expression in human endothelial cells: contribution of the NF-kappa b pathway.

In this study we aimed to investigate whether the therapeutic efficacy of anisodamine in the treatment of bacteraemic shock could--at least in part--be brought about by its direct interference with the lipopolysaccharide (LPS)-induced activation of endothelial cells. Thus, we investigated the effect of anisodamine on LPS-induced expression of plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF), two major markers of endothelial activation. PAI-1 was measured in the conditioned media of human umbilical vein endothelial cells (HUVEC) by a specific enzyme-linked immunosorbent assay (ELISA) whereas TF activity was measured in the lysates of these cells by using a single step clotting assay. Results obtained in these assays were confirmed on the level of specific mRNA expression by Northern blotting using specific probes for human PAI-1 or TF. In order to evaluate a possible contribution of the NF-kappa B pathway on the effects observed, electrophoretic mobility shift assays (EMSA) were performed using nuclear extracts from HUVEC and NF-kappa B-binding oligonucleotides. When HUVEC were treated with 1 microg/ml LPS a significant increase in PAI-1 and TF activity was observed compared with cells incubated without LPS. Anisodamine dose-dependently inhibited this LPS-induced upregulation of PAI-1 and TF. Anisodamine alone had no effect on the constitutive expression of PAI-1 and TF in these cells. These effects were also confirmed on the level of specific PAI-1 and TF mRNA expression by Northern blotting. Furthermore, we could show by EMSA that anisodamine completely abolished LPS-induced NF-kappa B DNA binding activity in nuclear extracts from HUVEC treated with LPS together with anisodamine. Thus, we provide evidence that anisodamine counteracts endothelial cell activation by inhibiting LPS-induced PAI-1 and TF expression in these cells. Its interference with the NF-kappa B pathway might - at least in part - contribute to this effect. The ability of anisodamine to counteract LPS effects on endothelial cells might be one underlying mechanism explaining its efficacy in the treatment of bacteraemic shock.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

Regulation of the fibrinolytic potential of cultured human umbilical vein endothelial cells: astragaloside IV downregulates plasminogen activator inhibitor-1 and upregulates tissue-type plasminogen activator expression.

We have investigated whether the saponin astragaloside IV (AS-IV), a 3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosylcycloastragenol, purified from the Chinese herb drug Astragalus membranaceus, which is used in traditional Chinese medicine to treat cardiovascular diseases, might affect the fibrinolytic potential of cultured human umbilical vein endothelial cells (HUVECs). When HUVECs were conditioned with AS-IV, a dose (0.01-100 microg AS-IV/ml)- and time-dependent decrease in plasminogen activator inhibitor type 1 (PAI-1) and an increase in tissue-type plasminogen activator (t-PA) synthesis were observed, which were significant from 1 microg AS-IV/ml and from 12 h of incubation with 100 microg AS-IV/ml. PAI-1 antigen decreased from 641 +/- 86 to 318 +/- 18 ng/10(5) cells/24 h, whereas t-PA antigen increased from 4.1 +/- 0.3 to 9.7 +/- 0.4 ng/10(5) cells/24 h after addition of 100 microg AS-IV/ml. PAI-1 activity decreased to 30% of control level, whereas t-PA activity and t-PA-PAI-1 complexes reached a maximum stimulation of 3- and 5-fold over control levels, respectively, in the conditioned media of HUVECs treated with 100 microg AS-IV/ml for 24 h. PAI-1-specific mRNA expression decreased to 55% (2.2 kb) and 72% (3.2 kb), 66% (2.2 kb) and 88% (3.2 kb), and 19% (2.2 kb) and 41% (3.2 kb) of control values after incubation for 6, 12 and 18 h, respectively, whereas t-PA-specific mRNA increased 2-, 2.5- and 1.4-fold in HUVECs treated with 100 microg/ml AS-IV for 6, 12, and 18 h, respectively. In conclusion our data give evidence that in fact AS-IV can increase the fibrinolytic potential of cultured HUVECs not only by upregulating the expression of t-PA as NG-R1 does, but also by downregulating the expression of PAI-1.

Antihypertensive Agents↗
PubMedDate not supplied

Effect of the protease inhibitor aprotinin on renal hemodynamics in the pig.

Aprotinin, the serine protease inhibitor that also inhibits glandular (urinary) kallikrein, or vehicle was infused into the aorta above the renal arteries of anesthetized pigs. Renal hemodynamic and functional parameters were followed over time and during hemorrhagic hypotension. Both renal cortical blood flow and glomerular filtration rate were maintained in vehicle-treated animals at mean arterial pressures as low as 70 mm Hg. As long as renal cortical blood flow and glomerular filtration rate were maintained during the progressive hypotension, urinary excretion rate of kallikrein (as defined by kinin-generating activity) was increased. In contrast, all aprotinin-treated animals had a decreased excretion rate, and the renal cortical blood flow declined with the mean arterial pressure during hemorrhage. The pattern of glomerular filtration rate and plasma renin activity was comparable in both aprotinin-treated and vehicle-treated hemorrhaged animals. Our findings suggest that the endogenous renal kallikrein-kinin system is required for functional renal vasodilatation to maintain renal cortical blood flow during hemorrhage and is therefore directly or indirectly responsible for adjustment of preglomerular resistance.

Analysis of Variance↗
PubMedDate not supplied

Plasminogen activator inhibitor-1 accelerates lung metastasis formation of human fibrosarcoma cells.

We have studied the effects of PAI-1 on the formation of metastasis using human fibrosarcoma cells and DNA transfection. A clone (1-3C), which shows low constitutive expression of PAI-1 and low metastatic potential to the lung, was selected from human fibrosarcoma cell line HT-1080. Newly-derived clones transfected with human PAI-1 cDNA showed a 3-5 fold increase in the antigen level of PAI-1. Further, these clones demonstrated a significant increase in both the number and incidence of lung metastases when inoculated into the tail vein of athymic mice. PAI-1 could be a prognostic marker and a target for understanding the physiology of metastasis, as well as for the treatment and prevention of hematogenous lung metastasis.

Animals↗