Double-blind study of the safety of clopidogrel with and without a loading dose in combination with aspirin compared with ticlopidine in combination with aspirin after coronary stenting : the clopidogrel aspirin stent international cooperative study (CLASSICS)

BACKGROUND

Combination therapy with the ADP receptor antagonist ticlopidine plus aspirin has emerged as standard care after coronary stenting. Clopidogrel, a new ADP receptor antagonist, has greater molar potency than ticlopidine and better safety/tolerability.

METHODS AND RESULTS

Patients (n=1020) were randomized after successful stent placement and initiated on a 28-day regimen of either (1) 300-mg clopidogrel loading dose and 325 mg/d aspirin on day 1, followed by 75 mg/d clopidogrel and 325 mg/d aspirin; (2) 75 mg/d clopidogrel and 325 mg/d aspirin; or (3) 250 mg BID ticlopidine and 325 mg/d aspirin. The primary end point consisted of major peripheral or bleeding complications, neutropenia, thrombocytopenia, or early discontinuation of study drug as the result of a noncardiac adverse event during the study-drug treatment period. The primary end point occurred in 9.1% of patients (n=31) in the ticlopidine group and 4.6% of patients (n=31) in the combined clopidogrel group (relative risk 0.50; 95% CI 0.31 to 0.81; P=0.005). Overall rates of major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization) were low and comparable between treatment groups (0.9% with ticlopidine, 1.5% with 75 mg/d clopidogrel, 1.2% with the clopidogrel loading dose; P=NS for all comparisons).

CONCLUSIONS

The safety/tolerability of clopidogrel (plus aspirin) is superior to that of ticlopidine (plus aspirin) (P=0.005). The 300-mg loading dose was well tolerated, notably with no increased risk of bleeding. Secondary end point data are consistent with the hypothesis that clopidogrel and ticlopidine have comparable efficacy with regard to cardiac events after successful stenting.

Relation of the site of acute myocardial infarction to the most severe coronary arterial stenosis at prior angiography

To determine whether the site of acute myocardial infarction (AMI) can be predicted on the basis of a previous coronary angiogram, 184 consecutive angiograms obtained between March 1972 and August 1990 in 92 patients who had undergone coronary angiography both before and after AMI without intervening bypass surgery or angioplasty were evaluated. Median time between the first coronary angiography and AMI was 26 months (range 1 to 144). On the first angiogram, most patients (89%) had 1- or 2-vessel disease, and 56 (61%) had an abnormal ventriculography. Seventy-two segments (78%) responsible for a future AMI were not significantly stenosed. On the second angiogram, AMI was related to the previously most stenotic segments in only 29 patients (32%). For these patients, median time between first coronary angiography and AMI was slightly shorter (22 vs 28 months; p = 0.04). The severity of the narrowing on the first angiogram was a poor predictor of subsequent AMI. It is concluded that in a selected, medically treated cohort, AMI is frequently related to a segment that was not the most stenotic one or was not even significantly stenosed at previous angiography, particularly with a long interval between the first angiogram and AMI.

Randomized evaluation of anticoagulation versus antiplatelet therapy after coronary stent implantation in high-risk patients: the multicenter aspirin and ticlopidine trial after intracoronary stenting (MATTIS)

BACKGROUND

Although the association of ticlopidine and aspirin has been shown to be superior to anti-vitamin K agents and aspirin after coronary stent implantation in low-risk patients, the latter combination has remained an unproven reference regimen for high-risk patients until recently.

METHODS AND RESULTS

We randomized 350 high-risk patients within 6 hours after stent implantation to receive during 30 days either aspirin 250 mg and ticlopidine 500 mg/d (A+T group) or aspirin 250 mg/d and oral anticoagulation (A+OAC group) targeted at an international normalized ratio of 2.5 to 3. The primary composite end point was defined as the occurrence of cardiovascular death, myocardial infarction, or repeated revascularization at 30 days. Patients were eligible if (1) the stent(s) were implanted to treat abrupt closure after PTCA; (2) the angiographic result after implantation was suboptimal; (3) a long segment was stented (>45 mm and/or >/=3 stents); or (4) the largest balloon inflated in the stent had a nominal diameter of </=2.5 mm. The primary cardiac end point was reached for 10 patients (5.6%) in the A+T group and 19 (11%) in the A+OAC group (relative risk [RR], 1. 9; 95% CI, 0.9 to 4.1; P=0.07). Major vascular and bleeding complications were less frequent in the A+T group (3 patients, 1.7%) than in the A+OAC group (12 patients, 6.9%) (RR, 4.1; 95% CI, 1.2 to 14.3; P=0.02).

CONCLUSIONS

High-risk patients should be treated with A+T rather than A+OAC after coronary stenting because the bleeding and vascular complications are significantly reduced and there is a marked trend suggesting a decrease in cardiac events.

Nanoparticles: their potential toxicity, waste and environmental management

This literature review discusses specific issues related to handling of waste containing nanomaterials. The aims are (1) to highlight problems related to uncontrolled release of nanoparticles to the environment through waste disposal, and (2) to introduce the topics of nanowaste and nanotoxicology to the waste management community. Many nanoparticles used by industry contain heavy metals, thus toxicity and bioaccumulation of heavy metals contained in nanoparticles may become important environmental issues. Although bioavailability of heavy metals contained in nanoparticles can be lower than those present in soluble form, the toxicity resulting from their intrinsic nature (e.g. their size, shape or density) may be significant. An approach to the treatment of nanowaste requires understanding of all its properties--not only chemical, but also physical and biological. Progress in nanowaste management also requires studies of the environmental impact of the new materials. The authors believe Amara's law is applicable to the impact of nanotechnologies, and society might overestimate the short-term effects of these technologies, while underestimating the long-term effects. It is necessary to have basic information from companies about the level and nature of nanomaterials produced or emitted and about the expectation of the life cycle time of nanoproducts as a basis to estimate the level of nanowaste in the future. Without knowing how companies plan to use and store recycled and nonrecycled nanomaterials, development of regulations is difficult. Tagging of nanoproducts is proposed as a means to facilitate separation and recovery of nanomaterials.

Cloning, yeast expression, and characterization of the coupling of two distantly related Arabidopsis thaliana NADPH-cytochrome P450 reductases with P450 CYP73A5

Two NADPH-cytochrome P450 reductase-encoding cDNAs were isolated from an Arabidopsis cDNA library by metabolic interference in a Saccharomyces cerevisiae mutant disrupted for its endogenous cpr1 gene. ATR1 encodes a protein of 692 amino acids, while ATR2 encodes either a 712-residue protein (ATR2-1), or a 702-residue protein (ATR2-2) depending on the choice of the initiation codon. Comparative analysis of ATR1 and ATR2-1 indicates 64% amino acid sequence identity and the absence of conservation in the third base of conserved amino acid codons. The two Arabidopsis reductases are encoded by distinct genes whose divergence is expected an early event in angiosperms evolution. A poly(Ser/Thr) stretch reminiscent of a plant chloroplastic targeting signal is present at the ATR2-1 N-terminal end but absent in ATR1. The cDNA open reading frames were expressed in yeast. The recombinant polypeptides were found present in the yeast endoplasmic reticulum membrane and exhibited a high specific NADPH-cytochrome c reductase activity. To gain more insight into the respective functions of the two reductases, the Arabidopsis cDNA encoding cinnamate 4-hydroxylase (CYP73A5) was cloned and co-expressed with ATR1 or ATR2 in yeast. Biochemical characterization of the Arabidopsis ATR1/CYP73A5 and ATR2-1/CYP73A5 systems demonstrates that the two distantly related Arabidopsis reductases similarly support the first oxidative step of the phenylpropanoid general pathway.

Emergency stenting for acute occlusion after coronary balloon angioplasty

Acute coronary artery occlusion complicates 2-12% of the balloon angioplasty procedures, and despite repeat angioplasty, emergency surgical revascularization is often necessary. We report our initial experience with the emergency implantation of endoluminal stents for acute vessel closure after coronary balloon angioplasty. Nine patients received one stent, and two patients received two stents during the study period. Implantation was technically successful in all patients; there were no deaths, no myocardial infarctions as evidenced by Q wave on the electrocardiogram, and no need for emergency surgery. One additional patient, not satisfying the study inclusion criteria, died 16 hours after stent implantation from left ventricular failure and intractable arrythmias. Two patients in the study group had a moderate creatinine phosphokinase rise during the first 48 hours after implantation. During a median follow-up period of 3 months (range, 1-20 months), there have been no deaths and no need for elective coronary bypass surgery. One patient required emergency recanalization 3 months after implantation because of acute occlusion of the stented segment with limited myocardial infarction. Six patients have undergone control angiography, and none has developed chronic restenosis within the stented segment. For selected patients, coronary artery stenting appears to be a promising alternative to emergency bypass surgery after acute vessel occlusion during balloon angioplasty.

Reperfusion arrhythmia: a marker of restoration of antegrade flow during intracoronary thrombolysis for acute myocardial infarction

We studied the effects of coronary recanalization on arrhythmogenesis in patients undergoing intracoronary thrombolysis during the early hours of myocardial infarction. Catheterization, ventriculography, coronary angiography, and intracoronary streptokinase infusion were performed in 22 patients. Twenty-one of 22 had thrombotic total occlusion of the infarct-related transient thrombolysis with reocclusion by the end of the procedure. In 12 of these 17 patients, restoration of antegrade coronary flow was accompanied by transient arrhythmia. In these 12 patients coronary angiography within seconds of onset of arrhythmia showed vessel patency in a previously totally occluded coronary artery. Two additional patients developed arrhythmias during streptokinase infusion but after reperfusion had already been established. Accelerated idioventricular rhythm was most often noted. Sinus bradycardia and atrioventricular block with hypotension occurred during restoration of flow in arteries supplying the inferoposterior left ventricle. These arrhythmias may be useful noninvasive markers of successful reperfusion during thrombolytic therapy in acute myocardial infarction.

Exhaled breath condensate pH is a robust and reproducible assay of airway acidity

Exhaled breath condensate (EBC) pH is low in several lung diseases and it normalises with therapy. The current study examined factors relevant to EBC pH monitoring. Intraday and intraweek variability were studied in 76 subjects. The pH of EBC collected orally and from isolated lower airways was compared in an additional 32 subjects. Effects of ventilatory pattern (hyperventilation/hypoventilation), airway obstruction after methacholine, temperature (-44 to +13 degrees C) and duration of collection (2-7 min), and duration of sample storage (up to 2 yrs) were examined. All samples were collected with a disposable condensing device, and de-aerated with argon until pH measurement stabilised. Mean EBC pH (n=76 subjects, total samples=741) was 7.7+/-0.49 (mean+/-SD). Mean intraweek and intraday coefficients of variation were 4.5% and 3.5%. Control of EBC pH appears to be at the level of the lower airway. Temperature of collection, duration of collection and storage, acute airway obstruction, subject age, saliva pH, and profound hyperventilation and hypoventilation had no effect on EBC pH. The current authors conclude that in health, exhaled breath condensate pH is slightly alkaline, held in a narrow range, and is controlled by lower airway source fluid. Measurement of exhaled breath condensate pH is a simple, robust, reproducible and relevant marker of disease.

Continued benefit of coronary stenting versus balloon angioplasty: one-year clinical follow-up of Benestent trial. Benestent Study Group

OBJECTIVES

This study sought to determine the 1-year clinical follow-up of patients included in the Benestent trial.

BACKGROUND

The Benestent trial is a randomized study comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in patients with stable angina and a de novo coronary artery lesion. Seven-month follow-up data have shown a decreased rate of restenosis and fewer clinical events in the stent group. It is not established whether this favorable clinical outcome is maintained for longer periods or whether coronary stenting defers restenosis and its subsequent clinical manifestations.

METHODS

To clarify this uncertainty, we updated clinical information on all but 1 of 516 patients enrolled in the Benestent trial (257 in balloon group, 259 in stent group) at least 12 months after the intervention. Major clinical events (primary clinical end point) were tabulated according to the intention to treat principle and included death, the occurrence of a cerebrovascular accident, myocardial infarction, the need for bypass surgery or a further percutaneous intervention in the previously treated lesion.

RESULTS

After 1 year, no significant differences in mortality (1.2% vs. 0.8%), stroke (0.0% vs. 0.8%), myocardial infarction (5.0% vs. 4.2%) or coronary bypass graft surgery (6.9% vs. 5.1%) were found between the stent and balloon angioplasty groups, respectively. However, the requirement for a repeat angioplasty procedure was significantly lower in the stent group (10%) than the balloon angioplasty group (21%, relative risk [RR] 0.49, 95% confidence interval [CI] 0.31 to 0.75, p = 0.001), and overall primary end points were less frequently reached by stent group patients (23.2%) than those in the balloon group (31.5%, RR 0.74, 95% CI 0.55 to 0.98, p = 0.04). No differences were found between groups with respect to functional class angina and prescribed medication at the time of follow-up.

CONCLUSIONS

These clinical follow-up data show that the benefit of elective native coronary artery stenting in patients with stable angina is maintained to at least 1 year after the procedure and results in a significantly reduced requirement for repeat intervention.

Percutaneous transluminal coronary angioplasty for chronic total coronary arterial occlusion

Experience is reported with 100 consecutive patients in whom percutaneous transluminal coronary angioplasty (PTCA) was attempted on chronically occluded coronary arteries that had no visible anterograde flow. Ninety-eight patients had angina and all had collateral vessels to the occluded artery on angiography. A movable guidewire/dilatation system was used in all cases. Overall initial PTCA success rate was 56% and was related to duration of occlusion (69% success rate for occlusions of 1 month or less, 50% for 1 to 6 months and 11% after 6 months). Complications were minor; no patient died or required emergency bypass operation. Of the 44 patients in whom PTCA failed, 20 underwent elective bypass surgery for relief of angina and 24 were treated medically. Follow-up at a mean of 8 months (range 1 to 48) was available for 49 of the 56 patients in whom PTCA was successful: 40 had subjective improvement, 6 no change and 3 felt worse. Control angiography was carried out in 40 of the 56 patients with primary success and showed long-term success in 18 and reocclusion or significant stenosis in 22. Of these 22, 11 were successfully treated by a second PTCA, 2 underwent operation and 9 were treated medically. Recanalization of totally occluded coronary arteries with no forward flow has a lower initial success rate (56%) than PTCA for stenoses and the recurrence rate is higher (55%), but effective relief of angina is achieved in successful cases. The risk of serious complications appears to be low.

Enzymatic microreactors in chemical analysis and kinetic studies

The fields of application of microreactors are becoming wider every year. A considerable number of papers have been published recently reporting successful application of enzymatic microreactors in chemistry and biochemistry. Most are devices with enzymes immobilized on beads or walls of microfluidic channels, whilst some use dissolved enzymes to run a reaction in the microfluidic system. Apart from model systems, mostly with glucose oxidase, horseradish peroxidase and alkaline phosphatase, the principal fields of application of microreactors are tryptic digestion of proteins and polymerase chain reaction in automated analyses of proteomic and genetic material, respectively. Enzymatic microreactors also facilitate characterization of enzyme activity as a function of substrate concentration, and enable fast screening of new biocatalysts and their substrates. They may constitute key parts of lab-on-a-chip and muTAS, assisting the analysis of biomolecules. This review provides systematic coverage of examples of reports on enzymatic microreactors published recently, as well as relevant older papers.

Localization of I2-imidazoline binding sites on monoamine oxidases

Imidazoline binding sites (IBS) were proposed to be responsible for some of the pharmacological and therapeutic activities of imidazoline and related compounds and have been classified into two subtypes, I1BS and I2BS. Convergent studies attribute a role in central blood pressure regulation to the I1BS. In contrast, the function of I2BS remains unknown. In the present study, by combining biochemical and molecular biology approaches, we show that 1) microsequencing of I2BS purified from rabbit kidney mitochondria allowed the recovery of four peptide sequence stretches displaying up to 85.7% similarity with human, rat, and bovine monoamine oxidases (MAO)-A and -B; 2) I2BS and MAO displayed identical biophysical characteristics as their activities, measured by [3H]idazoxan binding and [14C]tyramine oxidation, respectively, could not be separated using various chromatographic procedures; and 3) heterologous expression of human placenta MAO-A and human liver MAO-B in yeast, inherently devoid of I2BS and MAO activities, led to the coexpression of [3H]idazoxan binding sites displaying ligand-recognition properties typical of I2BS. These results show definitely that I2BS is located on both MAO-A and -B. The fact that I2BS ligands inhibited MAO activity independently of the interaction with the catalytic region suggests that I2BS might be a previously unknown MAO regulatory site.

A randomized adaptive phase II/III study of buparlisib, a pan-class I PI3K inhibitor, combined with paclitaxel for the treatment of HER2- advanced breast cancer (BELLE-4)

Background

Phosphatidylinositol 3-kinase (PI3K) pathway activation in preclinical models of breast cancer is associated with tumor growth and resistance to anticancer therapies, including paclitaxel. Effects of the pan-Class I PI3K inhibitor buparlisib (BKM120) appear synergistic with paclitaxel in preclinical and clinical models.

Patients and methods

BELLE-4 was a 1:1 randomized, double-blind, placebo-controlled, adaptive phase II/III study investigating the combination of buparlisib or placebo with paclitaxel in women with human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer with no prior chemotherapy for advanced disease. Patients were stratified by PI3K pathway activation and hormone receptor status. The primary endpoint was progression-free survival (PFS) in the full and PI3K pathway-activated populations. An adaptive interim analysis was planned following the phase II part of the study, after ≥125 PFS events had occurred in the full population, to decide whether the study would enter phase III (in the full or PI3K pathway-activated population) or be stopped for futility.

Results

As of August 2014, 416 patients were randomized to receive buparlisib (207) or placebo (209) with paclitaxel. At adaptive interim analysis, there was no improvement in PFS with buparlisib versus placebo in the full (median PFS 8.0 versus 9.2 months, hazard ratio [HR] 1.18), or PI3K pathway-activated population (median PFS 9.1 versus 9.2 months, HR 1.17). The study met protocol-specified criteria for futility in both populations, and phase III was not initiated. Median duration of study treatment exposure was 3.5 months in the buparlisib arm versus 4.6 months in the placebo arm. The most frequent adverse events with buparlisib plus paclitaxel (≥40% of patients) were diarrhea, alopecia, rash, nausea, and hyperglycemia.

Conclusions

Addition of buparlisib to paclitaxel did not improve PFS in the full or PI3K pathway-activated study population. Consequently, the trial was stopped for futility at the end of phase II.

Transcatheter closure of atrial septal defect and patent foramen ovale with ASDOS device (a multi-institutional European trial)

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.

Enhanced in vivo monooxygenase activities of mammalian P450s in engineered yeast cells producing high levels of NADPH-P450 reductase and human cytochrome b5

We have engineered yeast genomic DNA to construct a set of strains producing various relative amounts of yeast NADPH-P450 reductase (Yred) and human cytochrome b5 (Hb5). Expression of cDNAs encoding human P450 1A1, 1A2, 3A4, 19A and mouse P450 1A1 in the different oxido-reduction backgrounds thus constituted were achieved after strain transformation by plasmid-based P450-encoding expression cassettes. The results indicate that the level of Yred strongly affects all activities tested. In contrast, the amount of Hb5 affects activities in a manner that is dependent both on the P450 isoform considered and the Yred level. In a strain containing optimized amounts of Hb5 and Yred, human P450 3A4-specific testosterone-6 beta-hydroxylase activity can be enhanced as much as 73-fold in comparison with the activity observed in a wild-type strain. Bioconversion of sterols or xenobiotics was easily achieved in vivo using this new co-expression system.

Intra-arterial beta irradiation prevents neointimal hyperplasia in a hypercholesterolemic rabbit restenosis model

BACKGROUND

Intra-arterial gamma irradiation has been shown to reduce restenosis after balloon angioplasty. The use of beta emitters should allow similar effects while inducing less undue tissue irradiation radioprotection problems.

METHODS AND RESULTS

Flexible 90-yttrium (90Y) coils inside a centering balloon were used to allow homogeneous intraarterial dose delivery. One carotid and one iliac artery of 21 hypercholesterolemic rabbits were deendothelialized and then irradiated. Four dose schedules were studied: (1) control (dilated, nonirradiated); (2) 6 Gy; (3) 12 Gy; and (4) 18 Gy. Arterial specimens were histologically evaluated at 8 days and at 6 weeks. For all radiation doses at 8 days compared with controls, there was a significant decrease in bromodeoxyuridine-labeled cells (245 +/- 93 cells/cm in control, 42 +/- 27 in 6 Gy, 72 +/- 107 in 12 Gy, and 2 +/- 2 in 18 Gy groups; P < .001) and in total neointimal cells (891 +/- 415 cells/cm in control, 79 +/- 43 in 6 Gy, 192 +/- 264 in 12 Gy and 22 +/- 13 in 18 Gy groups; P < .0002). At 6 weeks, computer-derived histological percent area stenosis was reduced from 26 +/- 10% in the control group to 1 +/- 1.3% in the 18 Gy group (P < .0001), but lower doses had no significant effect.

CONCLUSIONS

Administration of intra-arterial beta irradiation with a 90Y source is technically feasible and compatible with an ordinary catheterization laboratory environment. A dose of 18 Gy effectively induces long-term inhibition of neointimal hyperplasia.

Characterization of recombinant plant cinnamate 4-hydroxylase produced in yeast. Kinetic and spectral properties of the major plant P450 of the phenylpropanoid pathway

Helianthus tuberosus cinnamate 4-hydroxylase (CYP73 or CA4H), a member of the P450 superfamily which catalyses the first oxidative step of the phenylpropanoid pathway in higher plants by transforming cinnamate into p-coumarate, was expressed in the yeast Saccharomyces cerevisiae. The PCR-amplified CA4H open reading frame was inserted into pYeDP60 under the transcriptional control of a galactose-inducible artificial promoter. Engineered S. cerevisiae strains producing human P450 reductase or normal or overproduced amounts of yeast P450 reductase were transformed to express recombinant CA4H. When grown on galactose, yeast cells produced CA4H holoprotein bound to the endoplasmic reticulum membrane as judged from the reduced iron/carbon monoxide difference spectrum centered at 452 nm and from typical cinnamate 4-hydroxylase activity upon coupling with the different P450 reductases and NADPH. Some CA4H protein was found also addressed to the yeast mitochondria but as a low-activity form. The spectral and kinetic characterizations of the yeast-produced CA4H in different redox protein environments are presented using both assays on yeast microsomal fractions and bioconversions on living cells. Results indicate that the microsomal system constituted by the overexpressed yeast P450 reductase and CA4H is characterized by a 1:1 coupling between NADPH oxidation and cinnamate hydroxylation and by one of the highest turnover numbers reported for an NADPH-dependent P450 reaction. Based on spectral perturbation and inhibition studies, coumarate appeared to have no detectable affinity for the enzyme. A possible geometry of the substrate recognition pocket is discussed in the light of these data.

A randomized evaluation of early revascularization to treat shock complicating acute myocardial infarction. The (Swiss) Multicenter Trial of Angioplasty for Shock-(S)MASH

AIM

To test whether emergency revascularization improves survival in patients with acute myocardial infarction and shock.

METHODS AND RESULTS

Patients with acute myocardial infarction and early shock were randomized either to undergo emergency angiography, followed immediately by revascularization when indicated, or to receive initial medical management. In five of the nine participating centres, patients with shock but not randomized were entered in a registry. Only 55 patients could be randomized. Of the 32 patients in the invasive group, 30 (94%) underwent early angiography, 27 (84%) PTCA, and one (4%) CABG. Twenty-two (69%) died within 30 days in the invasive group vs 18/23 (78%) in the medically managed group (ns, RR=0.88, 95% confidence interval 0.6-1.2). Among the registry patients, 24/51 were excluded from randomization solely because of patient or physician preference for the invasive approach: 23 (96%) of them underwent emergency angiography, 21 (88%) PTCA, and 12 (50%) died within 30 days. Among the remaining registry patients (n=27) only nine (33%) underwent early angiography, nine (33%) PTCA and 20 (74%) died.

CONCLUSION

We failed to demonstrate that emergency PTCA significantly improves survival in patients with acute myocardial infarction and early cardiogenic shock. Because the study was stopped prematurely, due to an insufficient patient inclusion rate, a clinically meaningful benefit of early reperfusion may have been missed.

Single-cell MALDI-MS as an analytical tool for studying intrapopulation metabolic heterogeneity of unicellular organisms

Heterogeneity is a characteristic feature of all populations of living organisms. Here we make an attempt to validate a single-cell mass spectrometric method for detection of changes in metabolite levels occurring in populations of unicellular organisms. Selected metabolites involved in central metabolism (ADP, ATP, GTP, and UDP-Glucose) could readily be detected in single cells of Closterium acerosum by means of negative-mode matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The analytical capabilities of this approach were characterized using standard compounds. The method was then used to study populations of individual cells with different levels of the chosen metabolites. With principal component analysis and support vector machine algorithms, it was possible to achieve a clear separation of individual C. acerosum cells in different metabolic states. This study demonstrates the suitability of mass spectrometric analysis of metabolites in single cells to measure cell-population heterogeneity.

Feasibility of intracoronary beta-irradiation to reduce restenosis after balloon angioplasty. A clinical pilot study

BACKGROUND

With the aim of decreasing the incidence of restenosis after coronary balloon angioplasty, we developed a technique of intracoronary beta-irradiation using an endoluminally centered pure metallic 90Y source. The purpose of the present study was to evaluate the clinical feasibility and safety profile of this approach with a dose of 18 Gy delivered to the inner arterial surface.

METHODS AND RESULTS

Between June 21 and November 15, 1995, fifteen patients (6 women and 9 men; mean age, 71 +/- 5 years) underwent intracoronary beta-irradiation immediately after a conventional percutaneous transluminal coronary angioplasty (PTCA) procedure. The PTCA/irradiation procedure was technically feasible in all attempted cases, and the delivery of the 18 Gy dose was accomplished without complications. In 4 patients, the intervention was completed through intra-arterial stent implantation because of dissection induced by the initial PTCA. During the follow-up period of 178 +/- 17 days (range, 150 to 225 days), no complication occurred that could be attributed to radiation therapy. No aneurysm or angiographically detectable thrombus was observed in any of the irradiated arterial segments. The clinical event rate (4 of 15 patients underwent further target lesion revascularization) and the angiographic follow-up (6 of 15 patients had a > 50%-diameter stenosis at the previously treated site) did not suggest a marked impact on the expected restenosis rate.

CONCLUSIONS

This early experience demonstrates that our approach is feasible, and no side effects attributable to radiation were noted during a 6-month period of follow-up. Whether higher doses of beta-irradiation will favorably affect post-PTCA restenosis in patients must await further evaluation.

Maximizing the expression of mammalian cytochrome P-450 monooxygenase activities in yeast cells

Cytochrome P-450s constitute a superfamily of mono-oxygenases which require the association with specific redox enzymes bound to the endoplasmic reticulum membrane for their activity. Conditions for the functional expression of these mammalian enzymes in yeast cells and the respective merits and limitations of currently used P-450 expression systems, are considered. The dependence of the mouse P-450 IA1 specific activity on the cytochrome expression level in yeast microsomes is studied and results demonstrate that the low amounts of endogenous NADPH-cytochrome P-450 reductase and cytochrome b5 which are naturally present, are limiting for the heterologous monooxygenase activities. The sequences encoding human liver cytochrome b5, the native and a modified form of the yeast NADPH-cytochrome P-450 reductase were cloned by making use of PCR techniques, over-expressed in yeast as functional forms, and characterized. New vectors allowing a high level of mammalian P-450 expression upon induction were also constructed and tested. A strategy for the construction of a co-expression system allowing maximal activity of mammalian cytochrome P-450s is discussed.

Impact of a public campaign on pre-hospital delay in patients reporting chest pain

OBJECTIVE

To decrease pre-hospital delay in patients with chest pain.

DESIGN

Population based, prospective observational study.

SETTING

A province of Switzerland with 380000 inhabitants.

SUBJECTS

All 1337 patients who presented with chest pain to the emergency department of the Hôpital Cantonal Universitaire of Geneva during the 12 months of a multimedia public campaign, and the 1140 patients who came with similar symptoms during the 12 months before the campaign started.

MAIN OUTCOME MEASURES

Pre-hospital time delay and number of patients admitted to the hospital for acute myocardial infarction (AMI) and unstable angina.

RESULTS

Mean pre-hospital delay decreased from 7h 50 min before the campaign to 4 h 54 min during it, and median delay from 180 min to 155 min (P < 0.001). For patients with a final diagnosis of AMI, mean delay decreased from 9 h 10 min to 5 h 10 min and median delay from 195 min to 155 min (P < 0.002). Emergency department visits per week for AMI and unstable angina increased from 11.2 before the campaign to 13.2 during it (P < 0.02), with an increase to 27 (P < 0.01) during the first week of the campaign; visits per week for non-cardiac chest pain increased from 7.6 to 8.1 (P = NS) during the campaign, with an increase to 17 (P < 0.05) during its first week.

CONCLUSIONS

Public campaigns may significantly reduce pre-hospital delay in patients with chest pain. Despite transient increases in emergency department visits for non-cardiac chest pain, such campaigns may significantly increase hospital visits for AMI and unstable angina and thus be cost effective.

Improvement of left ventricular contraction and relaxation synchronism after recanalization of chronic total coronary occlusion by angioplasty

Twenty patients with a chronic total coronary artery occlusion were studied before and 1 to 48 months (mean 9) after successful recanalization by angioplasty and compared with a group of 20 normal subjects. Before angioplasty, 19 of these 20 patients had angina. Collateral vessels to the distal part of the occluded vessel were visible in all 20 patients. A previous myocardial infarction was documented in 14 patients (9 with a Q wave and 5 with a non-Q wave infarction). At the time of follow-up, three patients were symptomatic: one had unstable angina and two had a positive stress test. The follow-up angiogram showed a significant restenosis in six patients and reocclusion in two. The mean ejection fraction had improved slightly from 59 +/- 11% to 63 +/- 9% (p less than 0.05). Left ventricular wall motion synchronism was studied using two variables for 128 shortening segments: the "time of peak contraction" and the "time of peak relaxation," as obtained from biharmonic Fourier transformation for each segment. Their respective standard deviations reflect the synchronism of contraction and relaxation. The mean standard deviations of the two variables expressed in degrees of one cardiac cycle (360 degrees) were respectively: 5.5 +/- 0.4 degrees for the time of peak contraction and 6.0 +/- 0.5 degrees for the time of peak relaxation in the 20 normal subjects, 11.7 +/- 1.7 degrees and 23.0 +/- 3.0 degrees before recanalization and 9.6 +/- 1.8 degrees and 12.5 +/- 2.2 degrees at follow-up in the group of 20 patients. These values were significantly higher (p less than 0.05) in the patients than in the normal group.(ABSTRACT TRUNCATED AT 250 WORDS)