Trasylol

Animal-derived medicinal products in Russia: Current nomenclature and specific aspects of quality control

ETHNOPHARMACOLOGICAL RELEVANCE

Animal-derived medicinal products (ADMP) had been extensively used in Russia and became a part of officinal medicine in 1778.

AIM OF THE STUDY

The aim of the current review was to analyse the ADMPs authorised in the Russian Federation and to identify specific aspects of quality evaluation of these medicinal products.

MATERIALS AND METHODS

Information of ADMPs was extracted from the online State Register of Medicinal Products of the Russian Federation. At the next stage, we systematically searched library catalogues, E-library.ru, Medline/PubMed, Scopus, Web of Science and Google Scholar databases to find data related to ADMP quality evaluation, clinically proven efficacy and safety.

RESULTS

For classification of ADMP, we propose an approach based on the raw material used: ADMPs derived from marine organisms, ADMPs from cattle and pigs and ADMPs from other terrestrial animals. The majority of ADMPs authorised in Russia are produced by local manufacturers. ADMPs are available in dosage forms of solution for parenteral administration (35% of all products) and lyophilisates for parenteral use (19%), tablets and capsules (17% and 11%, respectively), ointments (5%) and powders (3%). ADMPs belong to the following pharmacotherapeutic groups: medicines for tissue regeneration and repair stimulators (30%), digestive enzyme products (22%), anticoagulants (17%), proteolytic agents (6%) and medicines for the treatment of chronic prostatitis (5%). The most important approaches to standardisation of ADMPs are implementation of modern requirements for registration dossiers, development of risk-oriented approaches for evaluation of impurities, elaboration of advanced instrumental and in vitro test methods capable of replacing in vivo methods and harmonisation of the potency units used for standardisation.

CONCLUSIONS

The key features of ADMPs that help them retain their leading position in the pharmaceutical market are as follows: (i) their unique composition usually represented by a complex of biologically active substances; (ii) a high degree of affinity of the active ingredient of an ADMP to the human body and (iii) proved safety and clinical efficiency. Variability in the quality of raw ingredients, epidemiological situation and other conditions pose additional challenges for the development of ADMPs and for the standardisation.

Aprotinin and similar protease inhibitors as drugs against influenza

Efforts to develop new antiviral chemotherapeutic approaches are focusing on compounds that target either influenza virus replication itself or host factor(s) that are critical to influenza replication. Host protease mediated influenza hemagglutinin (HA) cleavage is critical for activation of virus infectivity and as such is a chemotherapeutic target. Influenza pathogenesis involves a "vicious cycle" in which host proteases activate progeny virus which in turn amplifies replication and stimulates further protease activities which may be detrimental to the infected host. Aprotinin, a 58 amino acid polypeptide purified from bovine lung that is one of a family of host-targeted antivirals that inhibit serine proteases responsible for influenza virus activation. This drug and similar agents, such as leupeptin and camostat, suppress virus HA cleavage and limit reproduction of human and avian influenza viruses with a single arginine in the HA cleavage site. Site-directed structural modifications of aprotinin are possible to increase its intracellular targeting of cleavage of highly virulent H5 and H7 hemagglutinins possessing multi-arginine/lysine cleavage site. An additional mechanism of action for serine protease inhibitors is to target a number of host mediators of inflammation and down regulate their levels in virus-infected hosts. Aprotinin is a generic drug approved for intravenous use in humans to treat pancreatitis and limit post-operative bleeding. As an antiinfluenzal compound, aprotinin might be delivered by two routes: (i) a small-particle aerosol has been approved in Russia for local respiratory application in mild-to-moderate influenza and (ii) a proposed intravenous administration for severe influenza to provide both an antiviral effect and a decrease in systemic pathology and inflammation.

Validation of a chemiluminescent enzyme immunometric assay for plasma adrenocorticotropic hormone in the dog

BACKGROUND

The concentration of canine adrenocorticotropic hormone (ACTH) is usually determined by radioimmunoassay. However, chemiluminescent assay techniques have many advantages for clinical endocrine testing.

OBJECTIVES

The objectives of this study were to validate a commercially available chemiluminescent assay for determination of canine ACTH concentration and to determine whether protease inhibitors are appropriate for use in the chemiluminescent assay system.

METHODS

Biological specificity was evaluated by treatment of 3 dogs with ovine corticotropin-releasing hormone (CRH) followed by serial measurements of ACTH and by comparison with a previously validated immunoradiometric assay. All samples were collected both in the presence and absence of aprotinin, a protease inhibitor. The assay was further evaluated by measurement of intra-assay precision, interassay precision, and recovery after dilution.

RESULTS

Baseline ACTH concentrations ranged from 5.6 to 15.3 pg/mL, and maximum ACTH concentrations of 158 to 1240 pg/mL were observed 30-60 minutes after CRH administration. Plasma samples collected with aprotinin had significantly lower ACTH concentrations than did samples collected without aprotinin. The intra-assay coefficients of variance (CVs) ranged from 4.1 to 8.2%, and interassay CVs ranged from 4.6. to 14.8%. Recovery after dilution with canine plasma ranged from 93.4 to 103.0% of predicted concentration; however, inadequate recovery was observed with other diluents. There was a high correlation with the immunoradiometric assay (r =.925) but a significant negative bias (-32.9, 95% confidence interval -50.8 to -14.9).

CONCLUSIONS

This chemiluminescent assay is a valid technique for measurement of ACTH in canine plasma. ACTH concentration measured by chemiluminescence is lower than that measured by immunoradiometry. Aprotinin decreases the measured concentration of ACTH, and this effect should be taken into account when interpreting results. Diluents supplied with the kit should not be used for dilution of canine samples.

Potential mechanisms for the plasmin-mediated release and activation of latent transforming growth factor-beta1 from the extracellular matrix of growth plate chondrocytes

Chondrocytes produce latent transforming growth factor-beta1 (TGF-beta1) in a small, circulating form of 100 kDa and also store latent TGF-beta1 in their matrix in a large form of 290 kDa containing the latent TGF-beta1 binding protein 1. As growth plate cartilage cells are exceptionally sensitive to TGF-beta1 and are known to produce plasminogen activator, the role of plasmin in the activation of soluble and matrix-bound latent TGF-beta1 was examined. As is true for other cell types, low-dose plasmin (0.01 U/ml) was found to release both active and latent TGF-beta1 from chondrocyte matrix in a time-dependent manner over 3 h. However, high-dose plasmin (1.0 U/ml) was found to release active TGF-beta1 more rapidly than low-dose plasmin, and this release ceased within 30 min; latent complex continued to be released over time (3 h). When high-dose plasmin was titrated against the serine protease inhibitors, aprotinin and alpha-(2-aminoethyl)benzenesulfonyl fluoride, results similar to low-dose plasmin were obtained, indicating that the effects of high-dose plasmin could be altered to mimic those of low-dose plasmin. No differences were observed on the effects of plasmin on the release of TGF-beta1 from the matrices of either growth zone or resting zone chondrocytes. We examined whether plasmin could further activate the truncated large latent TGF-beta1 complex of 230 kDa that was released into the media by plasmin. It is known that plasmin will activate the small latent complex, so this was compared with the truncated form. Plasmin completely activated the small latent complex, whereas a smaller, but significant, activation of the truncated form of latent TGF-beta1 also occurred. These studies may have relevance to normal physiological conditions, where plasminogen and/or plasmin is present in very small amounts in the cartilage and, therefore, small amounts of active TGF-beta1 would be present, and to pathological conditions such as fractures, where chondroprogenitor cells would be exposed to high concentrations of plasmin and, therefore, to short-term high concentrations of this potent chondrogenic growth factor.

Reduction of sodium deoxycholic acid-induced scratching behaviour by bradykinin B2 receptor antagonists

1. Subcutaneous injection of sodium deoxycholic acid into the anterior of the back of male ddY mice elicited dose-dependent scratching of the injected site with the forepaws and hindpaws. 2. Up to 100 microg of sodium deoxycholic acid induced no significant increase in vascular permeability at the injection site as assessed by a dye leakage method. 3. Bradykinin (BK) B2 receptor antagonists, FR173657 and Hoe140, significantly decreased the frequency of scratching induced by sodium deoxycholic acid. 4. Treatment with aprotinin to inhibit tissue kallikrein reduced the scratching behaviour induced by sodium deoxycholic acid, whereas treatment with soybean trypsin inhibitor to inhibit plasma kallikrein did not. 5. Although injection of kininase II inhibitor, lisinopril together with sodium deoxycholic acid did not alter the scratching behaviour, phosphoramidon, a neutral endopeptidase inhibitor, significantly increased the frequency of scratching. 6. Homogenates of the skin excised from the backs of mice were subjected to gel-filtration column chromatography followed by an assay of kinin release by trypsin from each fraction separated. Less kinin release from the fractions containing kininogen of low molecular weight was observed in the skin injected with sodium deoxycholic acid than in normal skin. 7. The frequency of scratching after the injection of sodium deoxycholic acid in plasma kininogen-deficient Brown Norway Katholiek rats was significantly lower than that in normal rats of the same strain, Brown Norway Kitasato rats. 8. These results indicate that BK released from low-molecular-weight kininogen by tissue kallikrein, but not from high-molecular-weight kininogen by plasma kallikrein, may be involved in the scratching behaviour induced by the injection of sodium deoxycholic acid in the rodent.

Determinants of kinin release in isolated rat hindquarters

We studied the determinants of kinin release into the venous effluent of rat hindquarters perfused with Krebs bicarbonate buffer. Kinin release in preparations perfused with control media (14.6 +/- 2.5-20.7 +/- 6.7 pg/15 min) was surpassed by that in preparations perfused with media containing kininase inhibitors (243 +/- 53 to 276 +/- 78 pg/15 min). Kinin release increased when purified kininogen (from 242 +/- 43 to 3,365 +/- 725 pg/15 min) or kallikrein (from 270 +/- 49 to 30,649 +/- 8,040 pg/15 min) was added to the perfusate. Conversely, kinin release fell when the kallikrein inhibitor aprotinin (from 272 +/- 58 to 122 +/- 27 pg/15 min) or soybean trypsin inhibitor (from 273 +/- 52 to 195 +/- 25 pg/15 min) was added. Both basal and kininogen-induced kinin release were attenuated in preparations perfused with media containing cycloheximide, a protein synthesis inhibitor, but kallikrein-induced kinin release was not. These data suggest that kinin release from perfused rat hindquarters reflects the activity of both the kinin-degrading and kinin-generating pathways and that the latter is sustained by a kallikrein manufactured de novo and by preexistent kininogen(s).

N-alpha-tosyl-L-lysine chloromethylketone prevents expression of iNOS in vascular smooth muscle by blocking activation of NF-kappa B

Certain cytokines and lipopolysaccharide stimulate expression of inducible nitric oxide synthase (iNOS) in vascular smooth muscle, an event that is regulated at the transcriptional level and appears to involve several transcription factors, including nuclear factor kappa B (NF-kappa B). Since proteases play an essential role in NF-kappa B activation, experiments were designed to clarify, in both cultured rat aortic smooth muscle cells (SMCs) and isolated rat aortas, whether protease inhibitors affect the interleukin-1 beta (IL-1 beta)-elicited expression of iNOS. The formation of NO was assessed by nitrite release in cultured SMCs and the attenuation of phenylephrine-induced contraction in aortic rings, the expression of iNOS by Western blot analysis and reverse transcription-polymerase chain reaction, and NF-kappa B activity in nuclear extracts by gel electrophoretic mobility shift assya. Exposure of cultured SMCs to IL-1 beta increased NF-kappa B binding activity within 30 minutes and was associated with nitrite accumulation and the appearance of iNOS protein 24 hours later. These responses were abolished in cells that had been exposed to the cytokine in the presence of the protease inhibitor N-alpha-tosyl-L-lysine chloromethylketone. Aprotinin and p-toluenesulfonyl-L-arginine methyl ester, two other protease inhibitors, also reduced the cytokine-stimulated release of nitrite and the level of iNOS protein. Exposure of rat aortic segments without endothelium to IL-1 beta activated NF-kappa B within 30 minutes and was associated with the appearance of iNOS mRNA and an attenuation of phenylephrine-induced contraction 6 hours later. These responses were blunted when the segments were incubated with the cytokine and N-alpha-tosyl-L-lysine chloromethyl ketone. The present observations indicate that protease inhibitors prevent iNOS expression in both cultured and native vascular SMCs by blocking the activation of NF-kappa B.

Sprouting and abnormal contacts of nonmedullated axons, and deposition of extracellular material induced by the amyloid precursor protein (APP) and other protease inhibitors

We have reported that the local administration of serine protease inhibitors (amyloid precursor protein with the Kunitz insert (APP K+), aprotinin, and leupeptin) to the rat sciatic nerve determines a sprouting response of myelinated axons, proliferation of Schwann cells, and demyelination, 5 to 7 days later. Further study of these nerves with the electron microscope revealed (i) a sprouting response of nonmedullated axons, (ii) the appearance of fine axons with a few turns of compact myclin, (iii) abnormal contracts of axons with basal laminae, with fibroblast-like cells, and between them, (iv) the occurrence of hemidesmosome- and desmosome-like junctions between Schwann cell processes, and between Schwann cells and axons, and (v) the appearance of amorphous and fibrillary extracellular deposits alongside the axolemma. The adjacent proximal and distal segments were normal, i.e., axons remained continuous, and the alterations were confined to the segment exposed to the protease inhibitors. Heated APP Kappa +, APP without the Kunitz insert (APP K-), bovine serum albumin, and saline, did not elicit cytological alterations. Our results suggest that these inhibitors of serine proteases (i) set free a sprouting drive of axons by disrupting an ongoing repressive mechanism: (ii) modify the adhesive properties of axons and Schwann cells, and (iii) alter the natural history of an extracellular material. The imbalance of an extracellular protease system may participate in the pathogenesis of Alzheimer's disease.

The invariant chain derived fragment CLIP is an efficient in vitro inhibitor of peptide binding to MHC class II molecules

The invariant chain derived peptide CLIP inhibits association of peptides to the class II peptide binding site. Two DR3 specific peptides, the microbacterial heat shock protein 65 derived peptide hsp3-13 and the naturally occurring invariant chain derived peptide Ii131-149 were employed to study binding inhibition by CLIP (Ii82-102) in a series of combinations. Incubation of detergent solubilized DR polypeptides from Ii-free cells with 500 microM of synthetic CLIP almost completely prevents binding of 50 microM subsequently added DR3-specific peptides. When CLIP and the peptides were added simultaneously to DR3 molecules, binding of hsp3-13 was abolished, whereas binding of Ii131-149 was only partially blocked. This indicates apparent affinity differences of the peptides. The addition of CLIP to preformed DR-peptide complexes substantially reduced binding of hsp3-13,while there was little effect on the DR associated Ii131-149. The profound inhibitory ability of CLIP, which in vivo would diminish binding of antigenic peptides, suggests an intracellular mechanism that abrogates the persistence of the CLIP-DR complex. The HLA-DM molecules have been suggested as candidates for this function. The strong in vitro binding of the naturally occurring peptide Ii131-149 to DR3 may suggest that only limited amounts of this peptide are available in vivo for competition of exogenous peptide binding to class II molecules.

Characterization of a thrombin-like enzyme, grambin, from the venom of Trimeresurus gramineus and its in vivo antithrombotic effect

A thrombin-like enzyme, grambin, was purified to homogeneity by gel filtration, affinity and ion-exchange chromatography from the venom of Trimeresurus gramineus. Its mol. wt was estimated to be 45,400 by SDS-PAGE under reduced conditions. The mass of neutral sugars in grambin is estimated to be 20.7% of total mass. Grambin's NH2-terminal ten amino acid residues show a high homology to other venom thrombin-like enzymes. It clots human fibrinogen with a specific activity of 220-250 NIH thrombin-equivalent units/mg protein. It preferentially releases fibrinopeptide A accompanied by a slow release of trace amounts of fibrinopeptide B as monitored by HPLC following enzyme treatment of fibrinogen. EDTA, aprotinin, hirudin and heparin did not affect the fibrinogen-clotting activity of grambin in purified human fibrinogen solution. Diisopropyl fluorophosphate, phenylmethylsulfonyl fluoride and leupeptin inhibited the clotting activity of grambin whereas iodoacetamide did not affect its activity, indicating that grambin is a serine protease rather than a cysteine protease. In addition, it caused defibrinogenation and showed a marked antiplatelet effect when administered intravenously to mice. It also significantly prolonged the time lapse of platelet-rich thrombus formation in the irradiated mesenteric venules of fluorescein sodium-treated mice. Therefore, grambin may be used as a therapeutic agent not only in treatment of venous thrombosis but also in prevention of arterial thrombosis.

Hormone-regulated Ca2+ channel in rat hepatocytes revealed by whole cell patch clamp

An inward current responsible for hormone regulated Ca2+ entry has been identified in cultured rat hepatocytes using whole cell patch clamp. Addition of 20 nM vasopressin or of 100 microM ATP induced the inward current, which could be observed more clearly after blocking an outward K+ current. This large outward K+ current, which appeared after addition of vasopressin or ATP, could be blocked either by replacing K+ with Cs+ in the external medium and in the pipette solution, or by simply including 0.5 microM apamin in the K(+)-containing external medium. The outward current appears to be carried by a Ca2+ activated K+ channel. In the presence of apamin, hepatocytes pretreated with vasopressin in a Ca(2+)-free media reveal an inward current on addition of external Ca2+ (5 mM). The current could also be elicited by addition of vasopressin when cells are preincubated in the presence of 5 mM external Ca2+. No current is seen on addition of Ca2+ in the absence of vasopressin. Initially, the inward current was ca 200-300 pA at -60 mV, but it declined rapidly over 3 min to ca 20 pA. The current approached zero, as an asymptote at positive potential, and appeared to be somewhat inwardly rectifying. Additions of 5 mM Mn2+ or 5 mM Ba2+ in place of Ca2+ produced little or no current. An inhibitor of ER Ca(2+)-ATPase, thapsigargin, could also trigger the cascade of events leading to plasma membrane conductance of Ca2+. The data suggest that hormone-stimulated Ca2+ entry into hepatocytes is mediated by a Ca(2+)-release activated channel highly specific for Ca2+. This is the first demonstration of such a channel in hepatocytes, though similar ones have been described in mast cells, in vascular endothelial cells and T-lymphocytes.

Mitosis of Schwann cells and demyelination are induced by the amyloid precursor protein and other protease inhibitors in the rat sciatic nerve

We studied the cytological alterations produced in the rat sciatic nerve by the amyloid precursor protein (APP) containing the Kunitz insert (APP K+) and other protease inhibitors. Conditioning of nerve segments with APP K+, aprotinin or leupeptin for 5 days or more resulted in mitosis of Schwann cells, demyelination of fibres, and a < 10-fold increase in Schwann cells, associated with demyelinated fibres. Altered fibres nevertheless involved a small part of the population. Nerve segments proximal and distal to the conditioned region showed almost no alteration. Conditioning with saline, heated APP K+, or APP without the Kunitz insert was not effective. We conclude that APP K+ and other protease inhibitors induce Schwann cells to enter the cell cycle, and once committed to proliferate they resorb their myelin. These functional properties of APP may be relevant to the pathogenesis of Alzheimer's disease.

Oral immunization against diphtheria and tetanus infections by fluid diphtheria and tetanus toxoids

Purified diphtheria toxoid incorporated in egg yolk and mixed with a medicinal plant seed was used to orally immunize rabbits against diphtheria infection. Animals were partially immunized against a lethal diphtheria toxin challenge. The immunity was complete when gastric enzyme juices were inhibited before oral vaccination by aprotinin, a natural protease inhibitor. Rabbits and monkeys were orally immunized against both diphtheria and tetanus in the same way by pre-treatment with aprotinin. Adult volunteers receiving protease inhibitor before administration of oral toxoids have shown a significant rise in specific circulating antitoxins.

Replication of influenza B virus in chicken embryos is suppressed by exogenous aprotinin

Chicken embryo proteinases, one of which is a blood clotting factor Xa-like proteinase, are known to effectively cleave the haemagglutinin (HA) of Influenza B viruses to permit their replication in chicken embryonated eggs. Here we show that injection of the serine proteinase inhibitor, aprotinin, into the allantoic cavity of eggs infected with Influenza B/Hong Kong/73 and B/Lee/40 viruses suppresses the viral HA cleavage and reduces the virus proteolytic activation and replication. Effective inhibition dose was determined as approximately 10.0 micrograms of aprotinin per embryo that corresponds to 0.1 microM concentration. However, heparin, which is known to be a direct inhibitor of the Factor Xa, was not able to suppress Influenza B virus hemagglutinin cleavage and replication in chicken embryo system. These data shed light on the pattern of proteinases involved in the Influenza B virus proteolytic activation and indicate that aprotinin possesses antiviral potential against Influenza B viruses.

Aprotinin aerosol treatment of influenza and paramyxovirus bronchopneumonia of mice

The therapeutic efficacy of aerosolized aprotinin, a natural proteinase inhibitor, against influenza and paramyxovirus bronchopneumonia of mice is shown. Small-particle aerosol of aprotinin solution was generated by a Collison type nebulizer and infected mice were exposed to aerosol atmosphere by four 30-40 min incubations per day for 6 days. This regimen provided an inhalation aprotinin dosage of approx. 6 micrograms/mouse/day. With such treatment more than 50% of mice infected with lethal doses of either influenza virus or paramyxovirus were protected from death. A suppression of the development of fatal hemorrhagic bronchopneumonia and a normalization of the body weight gain were observed in infected mice treated with aerosolized aprotinin. These data suggest that low doses of aerosolized proteinase inhibitors could be successfully applied against respiratory influenza-like virus diseases.

Trypsin immobilization on to polymer surface through grafted layer and its reaction with inhibitors

Trypsin was covalently immobilized and physically adsorbed on to the surface of poly(ethylene terephthalate) fibres using poly(acrylic acid) (PAAc) chains grafted on to the ozonized fibres. The covalent immobilization was accomplished through amide formation between amino groups of trypsin and carboxyl groups of grafted PAAc chains, with the use of water-soluble carbodiimide. A set of samples with surface concentrations of grafted polymer ranging from 0.03 to 2.5 micrograms/cm2 was used to study the effects of grafted layer on the enzymatic activity of immobilized trypsin and its inhibition by trypsin inhibitors of different molecular sizes. The amount of immobilized trypsin increased linearly with an increase in graft yield of fibres, but the activity of immobilized enzyme reached saturation at a certain graft yield, probably because of diffusion limitation for the transport of enzyme substrate molecules into the grafted PAAc layer. The reduction of inhibition with an increase in graft yield and in molecular weight of inhibitors was attributed to enhancement of steric hindrance and enzyme inactivation in the dense grafted layer. We also found that the adsorbed trypsin was inhibited more easily than the covalently immobilized at any concentration of the grafted PAAc and for any type of inhibitor used.

Fibrin sealant adhesive systems: a review of their chemistry, material properties and clinical applications

Fibrin sealants (FS) are the most successful tissue adhesives to date. They have many advantages over adhesive technologies such as cyanoacrylates and marine adhesives in terms of biocompatibility, biodegradation and hemostasis. There are several commercial products in Europe but none in the United States due to the current regulatory stance against pooled plasma blood products. Blood banks and interested investigators have implemented single- and patient autologous-donor production methods with some success. This article will review the history of FS research and development and describe the chemistry of fibrin(ogen) and the production of commercial and research products. Fibrin sealant and purified fibrin characterization is compared and contrasted. The material and adhesive properties are described, and a survey of the clinical applications in which FS has been used is included as well.

Involvement of nitric oxide and peptides in the inhibitory non-adrenergic, non-cholinergic (NANC) response in bovine mesenteric artery

The cyclic GMP mediated non-adrenergic non-cholinergic (NANC) relaxation in field stimulated bovine mesenteric artery and its modulation by various factors was studied. Electrical field stimulation of precontracted (Phe 2.5 microM or histamine 5 microM) bovine mesenteric arteries resulted in relaxations varying between 10-70% in different preparations. Tetrodotoxin (3 microM) completely blocked the inhibitory NANC response. Preincubation with high concentrations (100 microM-1 mM) of NG-nitro-L-arginine for 15 min. significantly reduced the relaxation induced by electrical field stimulation. Blockade of cyclooxygenases and prostaglandin synthesis by indomethacin had no effect on the relaxatory response to electrical field stimulation. Neither the alpha 2-adrenoceptor selective antagonist yohimbine (1 microM) nor the alpha 2-adrenoceptor selective agonist UK 14,304 (1 microM) had any significant effect on the electrical field stimulation-induced relaxation. Pertussis toxin (100 ng/ml) was without effect on relaxations elicited by electrical field stimulation. GTP in the concentration range 10 microM-1 mM slightly potentiated the relaxant response. N-carboxymethyl-Phe-Leu (an inhibitor of enkephalinase) or aprotinin (an inhibitor of several proteases) had no significant effect on the electrical field stimulation response. Addition of trypsin (100 U/ml) in combination with chymotrypsin (20 U/ml) significantly reduced the electrical field stimulation-induced relaxation. In the present study we have found indications for the involvement of nitric oxide and possibly also peptides in mediating the inhibitory NANC response (relaxation) in bovine mesenteric arteries.

Effects of aprotinin on anticoagulant monitoring: implications in cardiovascular surgery

This study was designed to evaluate anticoagulant monitoring of heparin and platelet function in the presence of aprotinin. Aprotinin added to heparinized whole blood at concentrations equal to (30 micrograms/mL), twice, and four times that used in cardiopulmonary bypass operations synergistically elevated the activated clotting time (ACT) (536 +/- 73, 651 +/- 86, and 787 +/- 71 seconds, respectively) over the value with heparin alone (384 +/- 66 seconds) (p < 0.001). In addition, the ACT of heparin-aprotinin mixtures supplemented with protamine showed that the heparin was not completely neutralized (131 +/- 12 versus 98 +/- 7 seconds). Specific tests revealed that the effect on ACT caused by aprotinin is not equal to the anticoagulant effect of heparin. Thus there is a risk of under-heparinization if the ACT is used as a monitor when aprotinin is present. Furthermore, protamine doses relative to the heparin concentration, and not relative to the ACT, should be used to reverse heparin. In studying the effects of aprotinin on platelet function, there was a significant inhibition of aggregation when normal platelets were supplemented with aprotinin, but not for platelets of postoperative patients. This suggests that aprotinin may interact more favorably with nonactivated platelet surfaces, reducing or inhibiting the expression of receptors. Thus it is necessary to treat a patient with aprotinin before beginning cardiopulmonary bypass. Based on these data, the effect of aprotinin on the hemostatic system and its drug interactions must be considered to optimize safety and efficacy during cardiopulmonary bypass operations.

Bactericidal activities of lysozyme and aprotinin against gram-negative and gram-positive bacteria related to their basic character

Bactericidal properties of aprotinin, a proteinase inhibitor and possibly a defence molecule in bovine species, and of chicken egg white lysozyme, known as muramidase, were investigated. Incubation of various bacteria in the presence of either aprotinin or lysozyme showed that both proteins killed Gram-positive as well as Gram-negative bacteria without addition of complement or EDTA. Denaturation of the two proteins by dithiothreitol did not lead to loss of their bactericidal potency. Electron microscopic examination of Escherichia coli incubated either with lysozyme or aprotinin revealed that the bacterial cytoplasms gradually disintegrated. Both aprotinin and lysozyme were demonstrated within the affected cytoplasm by immunogold labelling. The results suggest that the bactericidal potency of lysozyme is not only due to muramidase activity but also to its cationic and hydrophobic properties. The bactericidal activity of aprotinin is probably also related to both these properties rather than to its activity as proteinase inhibitor.

Regulation of plasma membrane permeability to calcium in primary cultures of rat hepatocytes

Experiments were designed to characterize the hormone sensitive transport of Ca2+ from the external media into rat hepatocytes maintained in culture. In the absence of added vasopressin, hepatocytes were nearly impermeable to Ca2+, whereas a significant and rapid influx of Ca2+ could be detected when external Ca2+ was added to hepatocytes after the addition of 20 nM vasopressin. The transport was measured as the initial rate of increase of free intracellular Ca2+ [( Ca2+]i) after Ca2+ addition to the external media. Most data were obtained from the majority of cells on a coverslip immersed in a spectrophotometric cuvette, but selected data were obtained by measuring Ca2+ changes in single cells. Ca2+ influx measured using a large number of cells was similar to data obtained using single cells. The Vmax of Ca2+ influx was 140 nM/s. Ca2+ transport was competitive with H+ so that the Km was 17.4 mM at pH 6.8, 3.7 mM at pH 7.4 and 1.8 mM at pH 7.8. Ca2+ influx was insensitive to external K+ (1 to 70 mM) and to the presence of 5 nM valinomycin, suggesting that it was independent of the electrical potential gradient across the plasma membrane. Transport also appeared to be insensitive to the activity of protein kinase C, which was varied by addition of the activator, 12-myristate 13-acetate phorbol ester, and by addition of the kinase inhibitor, staurosporine. Stimulation of transport following vasopressin addition exhibited a delay with a t1/2 of approximately 30 s. A vasopressin antagonist blocked the activation of transport, if added prior to vasopressin. However, experiments designed to determine the effect of hormone occupancy per se on transport activity indicated that continued hormone occupancy was not required. When the external medium was nominally Ca2+ free and an antagonist was added 1 min after vasopressin, Ca2+ entry, even 8 min after antagonist addition, was rapid. Conversely, preincubation with vasopressin antagonist in medium containing 0.5 mM Ca2+ dramatically lowered plasma membrane Ca2+ permeability. The ER Ca2+ pool emptied by vasopressin was refilled in the presence of vasopressin antagonist plus 0.5 mM Ca2+, but did not refill when the medium contained no added Ca2+. Under the conditions of these experiments, the Ca2+ levels of the ER hormone-sensitive Ca2+ pool were estimated as well as intracellular concentrations of inositol-1,4,5-trisphosphate. The Ca2+ levels of the endoplasmic reticulum correlated inversely with plasma membrane Ca2+ permeability, whereas cellular concentrations of inositol-1,4,5-trisphosphate did not correlate with Ca2+ permeability.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of Gaddum's substance R

1. When the isolated small intestine of the rat is perfused via the mesenteric artery, an oxytocic principle (Gaddum's substance R) is released which is detectable in the perfusate after 30 min and is present in samples collected 8 h later. 2. The oxytocic activity of substance R is lost after boiling but is unaffected by treatment with thioglycolate. Furthermore, atropine, methysergide and indomethacin failed to antagonize uterine contractions to substance R. 3. Neither substance R nor urinary kallikrein alone induce a contraction of the guinea-pig isolated ileum. However, in the presence of kininogen both substance R and urinary kallikrein produce a slow and prolonged contraction of the guinea-pig ileum. 4. The oxytocic and kininogenase properties of both substance R and urinary kallikrein are inhibited by Trasylol. 5. Soy bean trypsin inhibitor (SBTI) selectively inhibited both the oxytocic and the kininogenase activities of substance R but not those of urinary kallikrein. 6. Gel filtration of substance R resolved a single peak of oxytocic activity with an estimated molecular weight of 40 kDa. 7. We conclude that substance R is a kininogenase enzyme which may be distinguished from plasma kallikrein by its molecular weight and from urinary kallikrein by its susceptibility to SBTI. The exact nature of this enzyme remains to be elucidated.

The status of trypsin-like enzymes in squamous-cell carcinoma of the head and neck region

The activity of two proteases associated with tumour cells was studied using frozen sections of squamous-cell carcinoma and fluorescent probes for the enzymes. Four fluorescent probes were used to define the enzymic status of guanidinobenzoatase on the surface of the squamous carcinoma cells. Each of four probes demonstrated the location of cells possessing inactive guanidinobenzoatase, whereas adjacent cells of the same tumour exhibited active enzyme. It was shown that the inactive form of the enzyme was an inhibitor-enzyme complex that could be dissociated. In contrast, all of the squamous carcinoma cells possessed active trypsin-like enzymes that were recognised by fluorescent aprotinin molecules. The observed variation in enzymic status of these two tumour-associated enzyme systems is discussed in the context of a possible biological control mechanism for cell migration.

Inhibition of trypsin-like enzymes on cells with rhodamine-aprotinin

Aprotinin, a polypeptide inhibitor of trypsin-like enzymes, has been labelled with rhodamine. Rhodamine-aprotinin inhibits trypsin in free solution in an identical manner to aprotinin. Rhodamine-aprotinin binds to trypsin-like enzymes on cells in formaldehyde fixed wax embedded sections. This technique has been used to locate cells possessing trypsin-like enzymes by means of fluorescent microscopy. In the present study we have used this technique to locate tumour cells.

Augmentation by aprotinin of the renal response to vasopressin

We contrasted the renal effects of vasopressin in Brattleboro rats with and without pretreatment with aprotinin (20,000 KIU kg-1). In both treatment groups, vasopressin injected at 3 mU kg-1 sec caused in conscious rats elevation of urine osmolality and reduction of urine flow and urinary excretion of total solutes. However, these effects of vasopressin were significantly greater in aprotinin pretreated rats than in rats without aprotinin treatment. In ketamine-pentobarbital-anesthetized rats without aprotinin pretreatment, vasopressin infused at 2 mU kg-1 hr-1 elevated urinary kinin excretion but did not affect urine flow rate or osmolality; in contrast, in aprotinin-pretreated rats, the same dose of vasopressin did not increase urinary kinins but caused elevation of urinary osmolality and reduction of urine flow, solute excretion, and glomerular filtration rate. Aprotinin pretreatment in anesthetized rats also blunted the rise in kinin excretion elicited by vasopressin at a higher dosage, 5 mU kg-1 hr-1, but did not potentiate the vasopressin-induced antidiuresis. We conclude that aprotinin facilitates the expression of the antidiuretic effect of vasopressin at a low, but not at a high dosage. This effect of aprotinin may be a consequence of: renal kallikrein inhibition which prevents augmentation of renal kinins in response to increased vasopressin levels, or other unrecognized properties of aprotinin.

High protection of animals lethally infected with influenza virus by aprotinin-rimantadine combination

The successful therapeutic synergism of aprotinin and rimantadine, which are known to attack different viral targets, was demonstrated in influenza-virus-infected animals. Combined treatment with these drugs of mice infected with a highly lethal dose of mouse-adapted influenza virus prevented the development of fatal haemorrhagic pneumonia and protected about 75% of animals; whereas the separate administration of aprotinin and rimantadine induced 35% and 15% protection, respectively.

Effects on peritoneal proteolysis and hemodynamics of prophylactic and therapeutic infusions of high doses of aprotinin in experimental acute pancreatitis

Acute pancreatitis was induced in pigs by retrograde injection of Na-taurocholate into the pancreatic duct. Chromogenic peptide substrate assays showed increased trypsin (TRY) and plasma kallikrein activity (KK), parallel with a reduction of plasma prekallikrein (PKK) and functional kallikrein inhibition (KKI) values, in the peritoneal exudate in untreated animals. Intravenous high-dose pretreatment or therapy with aprotinin starting 3 h after the induction of acute pancreatitis resulted in significantly increased KKI capacity and unchanged KK and TRY activities in the peritoneal exudate. In test animals receiving aprotinin intravenously a significantly increased survival rate and improved cardiac output and arterial blood pressure were found during the 6-h observation period. All animals treated with aprotinin survived the observation period, whereas 63% of the untreated animals died. The study emphasizes the pathophysiological importance of the plasma kallikrein-kinin system in acute pancreatitis.

Alphavirus replication in cultured cells and infected animals is inhibited by antiproteinase agents

The influence of different antiproteinase agents on alphavirus replication was examined. Sindbis virus multicycle replication in cultured cells was suppressed by N-tosyl-phenylalanine chloromethyl ketone (TPCK), an inhibitor of chymotrypsin-like proteinases, and by aprotinin, an inhibitor of a wide spectrum of proteinases. Antiviral activity of TPCK was also demonstrated in Sindbis virus-infected animals. Parenteral injections of TPCK in infected mice reduced virus titers in brain and blood. The possible mechanism(s) of antiviral action of the antiproteinase agents are discussed.

Degradation of porcine relaxin by glutathione-insulin transhydrogenase and a neutral peptidase

The susceptibility of porcine relaxin and 125I-polytyrosyl-porcine relaxin to degradation by 3 purified enzymes involved in the degradation of insulin and proinsulin was examined. Rat liver glutathione-insulin transhydrogenase (GIT), which cleaves disulfide bonds in insulin, catalyzed a time- and concentration-dependent increase in trichloroacetic acid (TCA)-soluble radioactivity of relaxin. The Sephadex G-50 profile of the reaction products revealed conversion to the A- and B-chains. Relaxin competitively inhibited the degradation of insulin by GIT; however, kinetic analysis revealed insulin to be preferred over relaxin as a substrate. Rat liver cytosol neutral thiol peptidase (NTP) catalyzed a time- and concentration-dependent increase in the TCA solubility of relaxin and a shift in the Sephadex G-50 radioactivity profile to low molecular weight products. Kinetic analysis revealed that insulin and B-chain are preferred over relaxin as substrates for NTP. A third enzyme, rat kidney neutral metalloendopeptidase, which degrades proinsulin and insulin C-peptide but not insulin, also did not degrade porcine relaxin.

Effects of protease inhibitor pretreatment on hemodynamic performances and survival rate in experimental, acute pancreatitis

Acute pancreatitis was induced in pigs by manual retrograde injection of Na-Taurocholate into the pancreatic duct. Using chromogenic peptide substrate assays, increased plasma kallikrein activity (KK), paralleled by a reduction in functional plasma kallikrein inhibition values (KKI) were found in the peritoneal exudate in untreated animals. Several of the untreated animals experienced an increased trypsin activity (TRY) in the same exudate. Five out of eight animals died during a 6 hour observation period. Pretreatment with either Cl-INH or aprotinin given intravenously, resulted in a significantly increase in KKI capacity paralleled by unchanged KK and TRY activities in the peritoneal exudate. Furthermore, inhibitor pretreatment significantly improved hemodynamic performances (AP and CO) and the survival rate. The study underlines the pathophysiological importance of trypsin and the plasma kallikrein-kinin system during acute, severe pancreatitis.

Isolation and characterization of the alpha and beta subunits of the platelet-activating glycoprotein from the venom of Crotalus durissus cascavella

It was concluded in a previous paper that the high Mr platelet-activating glycoprotein isolated earlier from the venom of Crotalus durissus cascavella has an hexameric structure of the alpha 3 beta 3 type involving two distinct subunits. Data reported here demonstrate that these two subunits are separable from each other by ion exchange chromatography under denaturating conditions, have similar Mrs (alpha = 12,540 et beta = 13,770) and exist in a one to one ratio within the native molecule. Carbohydrate analysis indicated that they are both similarly glycosylated to a small extent. They have slightly different amino-acid compositions, a common N-terminal sequence up to the fifth residue and similar extinction coefficients at 280 nm. The native molecule has a calculated Mr of 78,930. Additional data demonstrated that convulxin from the venom of Crotalus durissus terrificus is the same platelet-activating agent as the presently described platelet-activating glycoprotein (PAG) from the venom of Crotalus durissus cascavella.

Xanthine:NAD+ oxidoreductase in the liver of grass snake Natrix natrix

The enzyme hydroxylating oxypurines in the liver of grass snake (Natrix natrix, Colubridae) was found to be a stable xanthine:NAD+ oxidoreductase (EC 1.2.1.37). The Michaelis constants for NAD+ and xanthine amounted to 14.4 and 12.3 microM, respectively. The enzyme affinity to hypoxanthine is lower than that to xanthine, but the former substrate is hydroxylated faster than the latter. The enzyme is only slowly and slightly (up to 22%) inhibited by NADH accumulating during xanthine hydroxylation. The above data and the time-course of hypoxanthine----xanthine----uric acid hydroxylation indicated that the kinetic properties of the snake liver enzyme provide in this uricotelic animal fast elimination of superfluous nitrogen derived from protein catabolism.

Survey of plant inhibitors of polymorphonuclear leukocyte elastase, pancreatic elastase, cathepsin G, cathepsin B, Hageman factor fragments, and other serine proteinases

Various flower bulbs and vegetable and legume seeds were tested for inhibitors of polymorphonuclear leukocyte elastase, pancreatic elastase, cathepsin G, cathepsin B, trypsin, alpha-chymotrypsin, Hageman factor fragments, plasma kallikrein, and plasmin. Calla bulbs contained a 33,000 dalton polymorphonuclear leukocyte elastase inhibitor and a 4,000 dalton cathepsin G inhibitor. Seeds of some members in the Cruciferae family, such as radish and broccoli, were found to contain one or more 2,500-4,000 dalton inhibitors which inhibited cathepsin G, trypsin, Hageman factor fragments, and plasmin, but not plasma kallikrein. These seeds also contained a 1,000 dalton cathepsin B inhibitor. The above inhibitors were probably polypeptides which inhibited proteinases by making an enzyme-inhibitor complex, with the exception of the cathepsin B inhibitor. These newly found inhibitors with their characteristic profiles of inhibition should be useful in biochemical and pathophysiological studies on granulocyte proteinases and enzymes of the coagulation and fibrinolytic pathways.

Newer concepts of analgesia and anesthesia

Intracerebroventricular (ICV) administration of the peptidase inhibitors amastatin, trasylol, bacitracin, or phe-D-ala and systemic administration of phenylmethylsulfonyl fluoride resulted in one or more of the following responses: analgesia, reduced withdrawal severity in opiate tolerant rats, alterations in motor activity and behavior, hypo- and hyperthermia and others; some of these effects were antagonized by naloxone, suggesting participation of opioid and other endogenous peptides. In addition, peptidase inhibitors enhanced analgesic and other responses to opioid peptides given ICV. Peptidase inhibition affords another method of inducing selective pharmacological responses such as pain relief in individuals resistant to other forms of therapy. ICV administration of beta-endorphin in the rat induces general anesthesia that is instantly reversed by systemic naloxone. Extensions of this work include identification of specific neural pathways that mediate anesthesia and characterization of opiate receptor subtype(s) at these sensitive loci. This approach offers the potential for the design of systemically effective opioid peptide anesthetics with little or no secondary effects and rapid reversibility.

Peptidase inhibitors reduce opiate narcotic withdrawal signs, including seizure activity, in the rat

Narcotic withdrawal was precipitated by administration of naloxone in a low dose at 2 h after the final dose of morphine in a 9-day dependency-inducing schedule. Withdrawal was characterized by leaps, increased nocifensor activity and by cerebral cortical epileptiform activity, the latter not generally reported to be prominent in narcotic withdrawal. Single large doses of morphine did not provoke epileptiform activity at 2 h postinjection but did induce an acute opioid dependency wherein a moderately high dose of naloxone, ineffective in non-dependent rats, provoked upward leaping and electrocortical epileptiform activity. Pretreatment of the 9-day dependent rats with peptidase inhibitors, administered intracerebroventricularly, significantly reduced withdrawal severity including the epileptiform activity. We propose that peptidase inhibitors protect certain species of endogenous opioids and/or other neuropeptides that tend to suppress expression of the narcotic withdrawal syndrome. Furthermore, our findings suggest that epileptiform activity is a nascent form of cerebral activity hitherto largely unnoticed in narcotic withdrawal and that neuropeptides may be involved in certain epileptic states.

Histochemical localization of kallikrein-like Pro-Phe-Arg-naphthylester esterase activity in the rat kidney

In the rat kidney the presence of the kallikrein-like pro-phe-argnaphthylester esterase activity was demonstrated by a simultaneous coupling azo dye method. The enzyme was identified as a serine-protease because it was inhibited by preincubation with diisopropyl-fluorophosphate and unaffected by sodium iodoacetate. Since kallikrein is a serine-protease and prophe-arg-naphthylester is a synthetic and sensitive substrate for kallikrein, the enzyme activity revealed by this method was considered to represent kallikrein, although non-kallikrein esterase activity is not totally excluded. The enzyme activity was localized mainly in the outer stripe of the outer medulla, with focal extensions primarily only in the lower half of the cortex corresponding to the medullary rays.

Inactivation during phagocytosis of leucine aminopeptidase, an ecto-enzyme of polymorphonuclear neutrophils

Changes in enzyme activities of the plasma membrane markers were examined during phagocytosis using guinea-pig polymorphonuclear neutrophils. Incubation of neutrophils with fresh serum-opsonized zymosan particles showed a significant reduction in leucine aminopeptidase activity, whereas 5'-nucleotidase and alkaline phosphodiesterase activities remained unchanged. Inactivation of leucine aminopeptidase activity was also observed by exposure of neutrophils to complement-opsonized zymosan particles, but not to non-opsonized zymosan, IgG-coated zymosan or polystyrene latex particles. Pretreatment of neutrophils with cytochalasin B, which prevents phagocytosis but not surface binding of particles, provoked inactivation to the same degree as when the cells were allowed to phagocytose the particles. However, the inactivation during phagocytosis was protected by serine protease inhibitors. These findings suggest that loss of leucine aminopeptidase activity from phagocytosing cells may be mediated by certain serine protease inhibitor-sensitive factor(s) which are probably activated by the attachment of an opsonized zymosan particle to a specific membrane receptor, probably the C3b receptor.