Barbara G. Utterback

Prognostic value of protein C concentrations in neutropenic patients at high risk of severe septic complications.

Objective To assess the prognostic value of protein C, endogenous activated protein C, and d-dimer concentrations in patients at high risk of developing severe septic complications secondary to cytostatic chemotherapy. Design Prospective, comparative, single-center study. Setting Specialized ward for treating patients with acute leukemia and associated intensive care unit at a university hospital. Subjects Twenty-six consecutive patients who developed either severe sepsis (n = 13) or septic shock (n = 13) during chemotherapy-induced neutropenia (leukocytes <1000/&mgr;L). Intervention None, other than standard care. Measurements and Main Results Baseline blood samples were obtained from 97 adult patients treated with intensive cytostatic chemotherapy. Serial blood sampling was performed in 62 of 97 patients who developed fever (>38.3°C). Thirteen patients progressed to severe sepsis and 13 patients to septic shock. Protein C, endogenous activated protein C, and d-dimer were measured in these 26 patients. At fever onset, protein C concentrations decreased from normal baseline concentrations and were significantly lower in the group of patients who progressed to septic shock compared with those who developed severe sepsis (medians for protein C activity: 23.1% vs. 69.5%;p = .0003). The median elapsed time between detection of fever and the diagnosis of severe sepsis or septic shock was 16 hrs and 12 hrs, respectively. All septic shock patients died, whereas patients who progressed only to severe sepsis survived. Conclusions Septic shock in neutropenic patients is associated with increased protein C consumption. The data demonstrate that the coagulation cascade is activated and produces a hypercoagulable state before the onset of clinical symptoms of severe sepsis and septic shock. Low protein C concentrations at the onset of fever and before the onset of clinical symptoms of severe sepsis or septic shock may have prognostic value in predicting an unfavorable outcome. Protein C measurements may help identify patients at risk in an early phase of neutropenic sepsis. It is also attractive to speculate that because low protein C concentrations were seen in these patients, protein C replacement may be beneficial in sepsis.

The clinical evaluation committee in a large multicenter phase 3 trial of drotrecogin alfa (activated) in patients with severe sepsis (PROWESS): role, methodology, and results.

ObjectiveIn the multinational PROWESS trial, drotrecogin alfa (activated) significantly reduced mortality rate in patients with severe sepsis compared with placebo. The use of large multiple-center trials can potentially complicate interpretation of results in severe sepsis populations because of variability in medical attitudes and practices and the frequency of confounding events such as protocol violations. The objective of this study was to perform a blinded, critical, integrated review of data from the 1,690 severe sepsis patients from 164 medical centers enrolled in the PROWESS trial using a Clinical Evaluation Committee. DesignBlinded, critical, integrated review of data. SettingParticipating sites. PatientsThe 1,690 severe sepsis patients from 164 medical centers enrolled in the PROWESS trial. InterventionsWe performed analyses of the optimal cohort, defined as patients who had full compliance with the protocol, had evidence of an infection, and received adequate anti-infective therapy. We also performed other analyses, including significant underlying disorders, life support measures, and causes of death. Measurements and Main ResultsThe optimal cohort of 81.4% of the intention-to-treat population [drotrecogin alfa (activated), n = 695; placebo, n = 680] had similar baseline severity of illness between the two groups, a similar pharmacodynamic effect, and a relative risk of death estimate consistent with that observed in the overall PROWESS trial (0.83, 95% confidence interval 0.69–0.99 vs. 0.806, 95% confidence interval 0.69–0.94). A beneficial effect of drotrecogin alfa (activated) similarly was observed in patients with significant underlying disorders (0.73, 95% confidence interval 0.57–0.93) who were more severely ill and had a higher percentage of patients forgoing life-sustaining therapy. In contrast with the original investigator determinations, a benefit associated with drotrecogin alfa (activated) treatment in urinary tract infection adjudicated by the Clinical Evaluation Committee was observed. ConclusionsThe survival benefit associated with drotrecogin alfa (activated) use was consistent with the results of the overall trial regardless of whether patients met criteria of the optimal cohort or had a significant underlying disorder.

ENHANCE: results of a global open-label trial of drotrecogin alfa (activated) in children with severe sepsis.

Objective: To gather additional 28-day all-cause mortality data and safety information for pediatric patients with severe sepsis who received drotrecogin alfa (activated) (DrotAA). Design and Setting: Single-arm, open-label, multicentered study conducted in 59 study sites in 15 countries. Patients: One-hundred eighty-eight children (term newborn to <18 yrs old) with severe sepsis were consecutively enrolled in the study. Intervention: Administration of DrotAA, 24 &mgr;g/kg/hr for 96 hrs. Main Outcome Measures: Four-day and 28-day all-cause mortality, safety information, and protein C levels. Results: One-hundred eighty-seven patients completed the study. The 4-day mortality rate was 7.0%, and the 28-day mortality rate was 13.4%. At baseline, 57.6% of patients were severely deficient in protein C (a level ≤40% of normal). There was a statistically significant association between increased 28-day mortality and decreased end-of-infusion protein C levels (p < .001), greater number of baseline organ dysfunctions (p < .001), and greater baseline ventilator use (p = .03). Bleeding was the most significant complication observed. Serious bleeding events (including anemia without a bleeding source) were experienced by 27.7% of patients (n = 52). Six of the serious bleeding events (3.2%) were considered related to administration of DrotAA. During infusion, serious bleeding events with an identified source of bleeding were experienced by 5.9% of patients (n = 11). Central nervous system bleeding was experienced by 2.7% (n = 5). Two of the intracranial hemorrhages were fatal and occurred postinfusion. Conclusions: Without a placebo control, no efficacy conclusions are possible. Subgroups at higher risk of death were identified, and the change in protein C level from baseline was predictive of survival. The most significant complication observed was bleeding. Risk factors for serious bleeding appear to be multiple organ failure, thrombocytopenia, and coagulopathy.

Characterization and pharmacological relevance of high affinity binding sites for [3H]LY186126, a cardiotonic phosphodiesterase inhibitor, in canine cardiac membranes.

[3H]LY186126, an analogue of the cardiotonic agent indolidan, was shown to bind reversibly and with high affinity (Kd=4 nM) to a single class of binding sites within canine myocardial vesicles. Binding site density measured in various cardiac membrane fractions correlated well with Ca2+-ATPase activity (r=0.94; p<0.01), but not with Na+,K+-ATPase or azide sensitive ATPase, indicating a localization of these sites within sarcoplasmic retlculum membranes. Divalent cations were required for binding and displayed the following order of activation: Zn2+ + Mn2+Mg2+Ca2+. Differential activation of [3H]LY186126 binding by various divalent cations was due to alterations in binding site density, rather than affinity. cGMP and selective inhibitors of type IV membrane-bound phosphodiesterase (SR-PDE), for example, indolidan, milrinone, imazodan, and enoxlmone, selectively displaced bound [3H]LY186126; caffeine, theophylline, and rolipram were relatively impotent as inhibitors of radiolabel binding. Kd values from displacement corves were highly correlated with IC50 values for inhibition of SR-PDE (r=0.92; p<0.001). In addition, Kd values correlated well with published ED50 values for increases in cardiac contractility in pentobarbital-anesthetized dogs (r=0.94; p<0.001). The results support the hypothesis that [3H]LY186126 labels the pharmacological receptor for the class of positive inotropic agents characterized as isozyme-selective phosphodiesterase inhibitors. Furthermore, the data suggest that the identity of the site labeled by [3H]LY186126 is SR-PDE, the type IV isozyme of cardiac phosphodiesterase located in the sarcoplasmic retlculum.

Safety and tolerability of duloxetine in the acute management of diabetic peripheral neuropathic pain: analysis of pooled data from three placebo-controlled clinical trials

Objective: Summarize safety and tolerability of duloxetine in treating diabetic peripheral neuropathic pain. Research design and methods: Pooled data from three double-blind, randomized studies with 12-week, placebo-controlled (acute) and 52-week, routine-care-controlled (extension) phases. Main outcome measures: Frequency/discontinuations due to treatment-emergent adverse events (TEAEs). Results: There were 1139 (placebo, n = 339; duloxetine, n = 800) and 867 (routine-care, n = 287; duloxetine, n = 580) patients in the acute and extension phases, respectively. Patient details were as follow: 60 years (mean age); Caucasian, 84%; and male, 57%. In the acute phase, there were significantly more TEAEs, duloxetine versus placebo (p = 0.001), the most common being nausea and somnolence. Discontinuations due to adverse events were significantly greater (12.5 vs 5.6%, p < 0.001), with similar outcomes in the extension phase. Baseline-to-endpoint aspartate transaminase/alanine transaminase were significantly increased and fasting plasma glucose was increased for duloxetine (0.67 mmol/l) versus decreased in routine-care (-0.64 mmol/l, p < 0.001). HbA1c was significantly increased, duloxetine vs routine-care, in the extension phase (52 vs 19%, p < 0.001). Endpoint measures neuropathy, nephropathy and retinopathy indicated no disease progression. Conclusions: Duloxetine was generally safe and well tolerated, with the three most commonly reported TEAEs being nausea, somnolence and constipation. Modest changes in glycemia were associated with duloxetine. Aspartate transaminase/alanine transaminase increases were transient and not considered predictive of more severe outcomes.

Specific binding of [3H]LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles.

LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for [3H]LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound [3H]LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that [3H]LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs.

Cardiac inotropic responses to calcium and forskolin are not altered by prolonged isoproterenol infusion.

Effects of prolonged isoproterenol infusion upon the density of cardiac calcium channels, calcium-mediated contractile responses, and the ability of forskolin to enhance tension development and cyclic AMP accumulation were studied in ventricular muscle preparations from Sprague-Dawley rats. Isoproterenol infusion (400 micrograms/kg per h s.c., 4 days) significantly decreased calcium channel density (Bmax) in cardiac microsomal membranes as quantified by a 32% decrease in specific [3H]nitrendipine binding sites; binding affinity (KD) was unchanged. A 57% decrease of beta-adrenoceptors confirmed homologous down regulation. To examine functional effects of decreased [3H]nitrendipine binding sites, responses to calcium, BAY K8644 and nifedipine were determined in isolated right ventricular strips. Significant decreases in basal developed tension were observed in muscles from isoproterenol-infused rats. However, concentration-dependent increases in contractility in response to CaCl2 or BAY K8644 were comparable, and the negative inotropic effect of nifedipine was unchanged. Whereas isoproterenol infusion was associated with significantly decreased basal cardiac cyclic AMP concentrations, exposure of ventricular strips from either vehicle- or isoproterenol-infused rats to 10 microM forskolin resulted in comparable increases in cyclic AMP and in developed tension. Cumulative, submaximal concentrations of forskolin also produced similar increases in contractility with maximum responses in ventricular strips from vehicle-infused animals attained at 4.4 microM forskolin. Higher concentrations resulted in automaticity. By contrast, ventricle from isoproterenol-infused animals responded to 14.4 microM forskolin with maximal increases in force of contraction.

Fused bicyclic Gly-Asp β-turn mimics with potent affinity for GPIIb-IIIa. Exploration of the arginine isostere

6-[4-Amidinobenzoyl]amino]-tetralone-2-acetic acid is a potent antagonist of GPIIb-IIIa. Substitution in the meta position of the benzamidine, or replacement with a heteroaryl amidine was tolerated in this series. Use of an acyl-linked 4-alkyl piperidine as an arginine isostere also provided active compounds. Compounds from this series provided substantial systemic exposure in the rat following oral administration.

Dibasic benzo[b]thiophene derivatives as a novel class of active site directed thrombin inhibitors: 2. Sidechain optimization and demonstration of in vivo efficacy.

Potent, subnanomolar thrombin inhibitors 4, 5, and 6 are developed through side chain optimization of novel, benzo[b]thiophene-based small organic entities 2 and 3 and through SAR additivity studies of the new structural elements identified. X-ray crystallographic studies of 4b-thrombin complex revealed a hydrophobic and an electrostatic interaction of these new elements with thrombin at the S2 and S3 binding sites. In vitro and in vivo pharmacological studies showed that 4, 5, and 6 are potent anticoagulants in human plasma with demonstrated antithrombotic efficacy in a rat model of thrombosis.

Dihydroisoquinolone RGD mimics. Exploration of the aspartate isostere

Abstract Disubstituted 3,4-dihydroisoquinolones that contain an ether-linked benzamidine at C6 and a β-substituted aspartate mimic at C2 offer enhanced affinity for GPIIb–IIIa relative to the non-substituted isoquinolone propionate. Alkyl substituents afforded a 10-fold increase in intrinsic activity while aryl substituents yielded a 40-fold improvement.