In einer tierexperimentellen Studie wurde der Einfluß der Betarezeptorenblocker Carvedilol (CAS 72956-09-3) und Metoprolol (CAS 37350-58-6) auf die myokardiale Perfusion, quantifiziert mittels Kontrastmittel-Echokardiographie, untersucht. Sechs Hunde wurden im interindividuellen Vergleich einer Behandlung mit den Prüfsubstanzen sowie einer Leerbehandlung unterzogen. Die Prüfsubstanzen Carvedilol (2 mg/kg KG) und Metoprolol (4 mg/kg KG) wurden oral 2 h vor dem Kontrastmittel verabreicht. Das Kontrastmittel BY963 (0,03 ml/kg KG) – ein neuartiges lungengängiges Echokontrastmittel, basierend auf Phospholipid-stabilisierten Mikrobläschen – bzw. physiologische Kochsalzlösung wurde intravenös dreimal in Abständen von 2,5 min injiziert. 5 min vor sowie 7,5, 10, 20 und 30 min nach der ersten Injektion wurden jeweils in 2,9 s je 60 digitalisierte Echokardiographie-Aufnahmen des Ventrikelseptums gewonnen. Daraus wurden mittlere Graustufenwerte ermittelt und Zeit-Intensitäts-Kurven für ein Zielareal im Ventrikelseptum errechnet. Die jeweiligen Veränderungen von den Ausgangswerten wurden als Veränderungen der lokalen Myokarddurchblutung gewertet. Nach allen Injektionen des Kontrastmittels kam es – im Gegensatz zu Injektionen von isotoner NaCl-Lösung – zu einer Opazifizierung des Myokards. In der Beobachtungszeit (30 min) kehrte die Kontrastintensität in keinem Fall zu den Ausgangswerten zurück. Die mittlere Intensitätszunahme betrug ohne Prämedikation + 7 ± 1,2 IU mit und −1,2 ± 1,0 IU ohne Kontrastmittel. Bei Prämedikation mit Metoprolol ergab sich eine Intensitätszunahme von + 7,4 ± 1,3 IU; unter Carvedilol waren es + 12,7 ± 2,3 IU. Während also die Kontrastintensität unter Metoprolol annähernd der Plazebo-Behandlung entsprach, wurde durch die Vorbehandlung mit Carvedilol die Kontrastintensität verstärkt, was auf eine bessere Myokarddurchblutung hinweist. Alle Präparategaben wurden problemlos vertragen. EKG-Veränderungen wurden nicht beobachtet. Die Herzfrequenz nahm unter Metoprolol deutlich ab. Der Blutdruck wurde durch Carvedilol stärker gesenkt als durch Metoprolol.

INTRODUCTION:Given that bisphosphonates reduce bone turnover, it is important to establish that their long-term administration does not impair bone quality. This paper describes a new model for simulation of fracture repair to evaluate several aspects of bone quality following long-term administration (34 or 36 weeks) of ibandronate in full-grown beagle dogs. METHODS:The treatment schedule consisted of continuous daily subcutaneous administration of a pharmacologically active dose (1 microg/kg/day) and two cyclical intermittent regimens providing a similar total dose per animal at the end of the experiment. Seven or 8 weeks before study end, 10 holes were drilled in the left tibia and bone marrow ablation was performed in the ipsilateral femur. Serial measurements for blood biochemistry (osteocalcin and iso-alkaline phosphatase) and bone mineral density (BMD; whole body and L1-L7) by dual-energy X-ray absorptiometry (DEXA) were performed during the experiment. Bone quality was determined at the end of the experiment by assessing early and late stage defect healing and structural, cellular, and dynamic histomorphometry (femur, tibia, and lumbar vertebrae L3 and L4). RESULTS:Healing of the drill hole defects, which simulate the first stage of fracture healing, was neither qualitatively nor quantitatively influenced by ibandronate. The same was true for the activation of cortical remodeling that occurs in the later stage of fracture healing, which started in Week 4 after surgery and declined after Week 8 in all groups. Additionally, no difference was found between the various regimens and the controls with respect to DEXA analyses, trabecular bone volume, cancellous bone tissue area, cancellous bone perimeter, osteoclast count, serum osteocalcin, or bone-specific alkaline phosphatase. DISCUSSION:In conclusion, the presence of the first and second steps of fracture healing and the fact that the histological features closely resemble those of fracture repair validate the development and characterization of a new model for simulation of fracture repair. A long-term study with a therapeutically active dose of ibandronate shows that ibandronate does not impair BMD, bone structure, bone repair, coupling, and serum parameters for bone formation and turnover after long-term administration.

In the past, some non-cardiovascular drugs have been identified as prolonging repolarization and evoking torsade de pointes. Concerns prompted the health authorities to request detailed investigations targeted on this issue. In particular, in vitro and in vivo pre-clinical studies are regarded as mandatory in order to assess properly the potential risk of new compounds. However, appropriate assessment is only possible if the methods used are standardized and validated, which cannot currently be completely guaranteed. Additionally, a suitable threshold should also be specified in pre-clinical test systems. If some findings indicate prolongation of repolarization, further investigations are needed in order to evaluate the potential risk or to get more insight into the mode of action. However, withdrawal of the compound from further development at any stage is another alternative in order to spare resources and to avoid regulatory problems. In any case, a proper evaluation of the benefit-risk ratio is mandatory when findings indicate that a new compound may prolong repolarization. (Eur Heart J Supplements 2001; 3 (Suppl K): K101-K104) (C) 2001 The European Society of Cardiology.

Evidence is growing that increased sympathetic drive has major impact on hemodynamic disorders underlying cardiovascular diseases. In particular, mechanisms mediated by adrenoceptors contribute substantially to increased resistance of peripheral vessels, mediated mainly by α-adrenoceptors, leading to hypertension and imbalance of oxygen demand and supply in coronary artery disease (CAD). In addition, sympathetically driven arrhythmogenicity and cardiac remodeling contribute substantially to progression of congestive heart failure (CHF). Consequently, it has been shown in a considerable number of well conducted clinical trials that adrenoceptor antagonists provide benefits for patients suffering from hypertension and CHF. For example, β-adrenoceptor antagonists do not only reduce the blood pressure of hypertensive subjects, but also prevent ischemic heart attacks in patients with CAD, and reduce the risk for suffering from late complications such as stroke or secondary myocardial infarction. In particular, β-adrenoceptor antagonists that are devoid of intrinsic sympathomimetic activities [1] have demonstrated strong cardioprotection. Furthermore, it has been recently shown that the neurohormonal antagonist carvedilol and the β1-adrenoceptor antagonists bisoprolol and metoprolol, are capable of slowing the progression of CHF as indicated by reduction in the rates of hospitalization and mortality [2–4, and metoprolol unpublished data]. The present paper reviews the adrenergic pharmacology of carvedilol established in various in vitro and in vivo experimental paradigms.

In order to target 17β-estradiol directly at bone we synthesized three 17β-estradiol-bisphosphonate conjugates (E2-BPs) with different esterase-sensitive linkers between both molecular moieties. The systemic administration of these compounds should result primarily in local estrogenic effects on bone with no or negligible systemic hormonal effects. Only if a considerable margin exists between the doses required for inhibition of bone loss and those for systemic hormonal effects can such a pro-drug be considered acceptable for patients refusing systemic estrogen replacement therapy for several reasons. The conjugates were tested in vitro for their 17β-estradiol release in rat serum and in vivo for their local and systemic effects in rats: in vitro, the conjugates expressed cleavage resistance, low cleavage (4.8%), or high cleavage (33.1%) within 48 hours of incubation. The conjugate with the low-cleavage doubled 17β-estradiol serum half-life (3.78 hours) whereas the highcleavage conjugate resulted in approximately four times higher serum half-life (8.36 hours) when compared with free 17β-estradiol. In ovariectomized rats, bone loss was optimally prevented by 50 nmol/kg/day of 17β-estradiol when administered S.C. over a period of 5 weeks, and protection against uterine atrophy was achieved at doses as low as 5 nmol/kg/day. The cleavage-resistant conjugate was ineffective in preserving bone and uterus in doses ranging from 5 to 150 nmol/kg/day. The other two E2-BPs revealed a dose-dependent inhibition of bone loss which was paralleled by the respective uterus weight with a dose range of 1.5–150 nmol/kg/day being fully effective in a range similar to 17β-estradiol alone. The higher sensitivity of the uterus versus bone to protective estrogenic effects (1:10) was abolished by the conjugates. We conclude that E2-BPs containing esterase-sensitive linkers failed to act as bone-seeking pro-drugs expressing primarily local effects on bone without systemic effects.

Patients with non-small cell lung carcinoma (NSCLC) bearing epidermal growth factor receptor (EGFR) gene mutations are good responders to gefitinib (Iressa), an EGFR tyrosine kinase inhibitor (EGFR-TKI), yet these patients may eventually develop acquired resistance to all available EGFR-TKIs. Nitrogen-containing bisphosphonates (N-BPs) are inhibitors of farnesyl diphosphate (FPP) synthase as well as chelators of divalent cations. This study was undertaken to examine if the N-BP zoledronic acid (zoledronate) possessing antitumor activity could enhance the antitumor effect of gefitinib on the HCC827 NSCLC cell line expressing mutated EGFR. Both gefitinib and zoledronate were cytotoxic to HCC827 cells when treated alone. Combined treatment with gefitinib (0.025 μM) that induced G0/G1 arrest and zoledronate (50 μM) that caused S/G2/M accumulation generated an additive induction in cell cytotoxicity, sub-G1 cell population, and apoptosis. Gefitinib suppressed EGF-activated phosphorylation of ERK1/2 and Akt, while zoledronate seemed to impose its pharmacological effect independent of ERK1/2 and Akt phosphorylation. The volumes of xenografted tumors in nude mice co-administered with gefitinib (1 mg/kg/day, five days a week, p.o.) and zoledronate (10 μg/kg, twice weekly, i.p.) were significantly smaller than those of tumors in mice treated with gefitinib alone at the last stage of a 6-week in vivo study. Severe peri-tumoral fat loss frequently observed in gefitinib-treated mice disappeared in mice receiving the combined treatment. Hence, combined treatment of gefitinib with zoledronate may form a basis to develop a more effective and less toxic therapy for NSCLC with EGFR gene mutations.

We used a canine model of embolic pulmonary hypertension induced by intravenous (i.v.) injection of autologous thrombi to evaluate whether the novel recombinant plasminogen activator (r-PA) BM 06.022 reversed pulmonary hypertension. The effects of BM 06.022 after bolus injection were compared with those of vehicle, alteplase, urokinase, and anistreplase in 6 dogs per group. Thirty minutes after initiation of treatment, the decrease in pulmonary artery pressure (PAP) caused by a bolus of 200 kU/kg (0.35 mg/kg) BM 06.022 was greater (p < 0.05) than that caused by a 2-h infusion of 1.33 mg/kg alteplase or of 40 000 U/kg urokinase and that caused by a bolus of 0.4 U/kg anistreplase but not that caused by a 15-min infusion of 1 mg/kg alteplase. At 3 h, all thrombolytic agents had reduced PAP equally. The greatest measured plasma concentration of BM 06.022 was higher (p < 0.05) than that of 2-h infused alteplase (4,498 +/- 716 vs. 519 +/- 119 IU/ml). We conclude that because of its bolus-pharmacokinetics, BM 06.022 more rapidly reversed thromboembolic pulmonary hypertension than did 2-h infusion of alteplase or urokinase or a bolus of anistreplase.

BM 06.022 is a novel recombinant, unglycosylated plasminogen activator comprising only the kringle 2 and protease domains of human tissue-type plasminogen activator (t-PA), and it has a longer half-life than t-PA. Because t-PA is mainly cleared by the liver, rat models of hepatic and renal insufficiency were used to identify the main catabolic organ of BM 06.022, compared with alteplase (recombinant t-PA). Hepatic insufficiency in rats was chemically induced by pretreatment with carbon tetrachloride for 1 day; renal insufficiency was achieved by acute bilateral, surgical nephrectomy. Plasma concentration of functionally active BM 06.022 or alteplase was measured by an indirect spectrophotometric assay. Intravenous administration of 200 kU/kg of BM 06.022 or alteplase over 15 sec to rats with hepatic failure or olive oil pretreatment as control did not significantly alter the total plasma clearance (CL) of BM 06.022 vs. control (4.9 +/- 0.5 vs. 5.7 +/- 0.5 ml.min-1 x kg-1, NS) in contrast to alteplase (32.1 +/- 6.5 vs. 82.3 +/- 12.9 ml.min-1 x kg-1, p < 0.05). Renal insufficiency increased the CL of BM 06.022 vs. sham surgery (3.1 +/- 0.4 vs. 6.3 +/- 0.5 ml.min-1 x kg-1, p < 0.05) in contrast to alteplase (33.2 +/- 5.2 vs. 37.2 +/- 7.2 ml.min-1 x kg-1, NS). In vitro incubation of 2000 U/ml BM 06.022 or alteplase in citrate blood and plasma demonstrated a decrease of the plasma concentration with a shorter (p < 0.001) half-life for BM 06.022 than for alteplase in blood (71.9 +/- 3.1 vs. 130 +/- 3.3 min) and in plasma (62.9 +/- 1.2 vs. 129.9 +/- 5.3 min).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of the unglycosylated recombinant plasminogen activator BM 06.022, consisting of the kringle 2 and protease domains of tissue-type plasminogen activator (t-PA), on clot lysis were evaluated in an in vitro system. Fresh and aged 125I-labelled human platelet-poor (PPP) and platelet-rich plasma (PRP) and whole blood clots were immersed in human plasma. Clot lysis was quantitated by measurement of released 125I. Fresh PPP clots were time- and concentration-dependently lysed by BM 06.022, alteplase, melanoma t-PA (mt-PA), and urokinase. Fifty per cent clot lysis at 4 h required 3.2-, 6.4- and 15.2-fold higher nM concentrations of mt-PA, BM 06.022, and urokinase respectively compared with alteplase. Maximal lysis (Emax) at 4 h was similar (84.1-87.6%) for BM 06.022, alteplase, and mt-PA, but lower (65.3 +/- 0.6%) for urokinase. Emax for BM 06.022 was lower (P < 0.05) than for alteplase for fresh and aged PRP and whole blood clot lysis. These data suggest that in vitro BM 06.022 achieved, compared with alteplase, the same maximal efficacy in fresh PPP-clot lysis despite a lower potency, but was less effective in lysing aged and fresh PRP and whole blood clots.

Cardiovascular Drug ReviewsVolume 11, Issue 3 p. 299-311 Free to Read BM 06.022: A Novel Recombinant Plasminogen Activator Ulrich Martin, Ulrich Martin Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorRainer Bader, Rainer Bader Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorErwin Böhm, Erwin Böhm Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorUlrich Kohnert, Ulrich Kohnert Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorErika von Möllendorf, Erika von Möllendorf Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorStephan Fischer, Stephan Fischer Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorGisbert Sponer, Corresponding Author Gisbert Sponer Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Address correspondence and reprint requests to Prof. Dr. G. Sponer at Department of Pharmacology, Boehringer Mannheim GmbH, W-6800 Mannheim 31, Germany.Search for more papers by this author Ulrich Martin, Ulrich Martin Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorRainer Bader, Rainer Bader Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorErwin Böhm, Erwin Böhm Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorUlrich Kohnert, Ulrich Kohnert Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorErika von Möllendorf, Erika von Möllendorf Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorStephan Fischer, Stephan Fischer Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Search for more papers by this authorGisbert Sponer, Corresponding Author Gisbert Sponer Pharmaceutical Research and Development, Boehringer Mannheim GmbH, Mannheim and Penzberg, Germany.Address correspondence and reprint requests to Prof. Dr. G. Sponer at Department of Pharmacology, Boehringer Mannheim GmbH, W-6800 Mannheim 31, Germany.Search for more papers by this author First published: September 1993 https://doi.org/10.1111/j.1527-3466.1993.tb00193.xCitations: 29AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume11, Issue3September 1993Pages 299-311 RelatedInformation

Objectives. We sought to evaluate whether anticoagulation by an intravenous heparin infusion prevents deterioration of coronary blood flow restored by the novel recombinant plasminogen activator BM 06.022, and to compare the effects of profound fibrinogenolysis with those of an intravenous bolus injection of heparin.Background. Recent clinical studies indicate that heparin appears to be effective in reducing reocclusion when combined with recombinant tissue-type plasminogen activator (rt-PA), but that heparin is associated with an increased bleeding incidence. Therefore, the need for heparin has to be critically evaluated in the development of BM 06.022.Methods. BM 06.022 is an unglycosylated variant of human tissue-type plasminogen activator. Thrombus formation in anesthetized open chest dogs was induced by electrical injury. Left circumflex coronary artery blood flow was monitored for 4 h using an electromagnetic flow probe. Twenty dogs were randomized to receive intravenous heparin (100 IU/kg bolus plus 100 IU/kg per h) in group B or saline solution in group A before an intravenous bolus injection of 200 kU/kg (=0.34 mg/kg) BM 06.022 1 h after thrombus formation. Another 14 dogs were randomized to receive a single intravenous bolus injection of 200 IU/kg heparin plus 200 kU/kg BM 06.022 in group D or saline solution plus 1,000 kU/kg BM 06.022 in group C.Results. In the absence of a systemic lytic state, heparin infusion prolonged (p < 0.05) the cumulative patency time (sum of time intervals during which the coronary artery was patent) to 204.3 +/- 7.4 min (group B) compared with 34.6 +/- 10.8 min with saline solution (group A), and increased (p < 0.05) the area under the curve for coronary blood flow versus time (AUC(Flow)) to 34.0 +/- 3.4 ml.h.min-1 compared with 7.7 +/- 4.6 ml-h.min-1. Profound fibrinogenolysis after administration of 1,000 kU/kg BM 06.022 (group C) and a single intravenous heparin injection (group D) did not differ in their effects on the cumulative patency time (182 +/- 30.3 vs. 177.5 +/- 25.4 min) and AUC(Flow) (36.0 +/- 10.3 vs. 30.5 +/- 4.8 ml.b.min-1), but these values were improved (p < 0.05) compared with those obtained after administration of saline solution plus 200 kU/kg BM 06.022 (group A).Conclusions. In the absence of a systemic lytic state, intravenous heparin is required as an adjunct to BM 06.022 to maintain coronary blood flow in dogs.