External validation of established risk adjustment models for procedural complications after percutaneous coronary intervention

BACKGROUND

Workable risk models for patients undergoing percutaneous coronary intervention (PCI) are needed urgently.

OBJECTIVE

To validate two proposed risk adjustment models (Mayo Clinic Risk Score (MC), USA and North West Quality Improvement Programme (NWQIP), UK models) for in-hospital PCI complications on an independent dataset of relatively high risk patients undergoing PCI.

SETTING

Tertiary centre in northern England.

METHODS

Between September 2002 and August 2006, 5034 consecutive PCI procedures (validation set) were performed on a patient group characterised by a high incidence of acute myocardial infarction (MI; 16.1%) and cardiogenic shock (1.7%). Two external models-the NWQIP model and the MC model-were externally validated.

MAIN OUTCOME MEASURE

Major adverse cardiovascular and cerebrovascular events: in-hospital mortality, Q-wave MI, emergency coronary artery bypass grafting and cerebrovascular accidents.

RESULTS

An overall in-hospital complication rate of 2% was observed. Multivariate regression analysis identified risk factors for in-hospital complications that were similar to the risk factors identified by the two external models. When fitted to the dataset, both external models had an area under the receiver operating characteristic curve >or=0.85 (c index (95% CI), NWQIP 0.86 (0.82 to 0.9); MC 0.87(0.84 to 0.9)), indicating overall excellent model discrimination and calibration (Hosmer-Lemeshow test, p>0.05). The NWQIP model was accurate in predicting in-hospital complications in different patient subgroups.

CONCLUSIONS

Both models were externally validated. Both predictive models yield comparable results that provide excellent model discrimination and calibration when applied to patient groups in a different geographic population other than that in which the original model was developed.

Maternal dietary n-3 fatty acids alter immune cell fatty acid composition and leukotriene production in growing chicks

The effect of feeding different amounts of n-6 and n-3 fatty acids (FA) to hens on immune tissue FA composition and leukotriene production of hatched chicks was investigated. Hens were fed diets supplemented with either 3.0% sunflower oil (Diet I), 1.5% sunflower+1.5% fish oil (Diet II), or 3.0% fish oil (Diet III) for 46 days. The hatched chicks were fed a diet containing C18:3n-3, but devoid of longer chain n-6 and n-3 FA, for 21 days. Spleen docosahexaenoic acid (DHA) content was higher in chicks from hens fed Diet III (P<0.05). The bursa content of arachidonic acid was lower in chicks hatched from hens fed Diet III (P<0.05), and the ratio of n-6 to n-3 FA was significantly higher in bursa of chicks hatched to hens fed Diet I (P<0.05). Eicosapentaenoic acid (EPA) and DHA contents were higher in bursa of chicks hatched from hens fed Diet III (P<0.05). Thrombocytes from chicks hatched to hens fed Diet III produced the most leukotriene B(5) (LTB(5)). The ratio of LTB(5) to LTB(4) concentrations was also highest (P<0.05) in chicks hatched to hens fed Diet III. These results indicate that modulating maternal dietary n-6 and n-3 FA may alter leukotriene production in chicks, which could lead to less inflammatory-related disorders in poultry.

Prospective, randomised, controlled trial to study the effect of intracoronary injection of verapamil and adenosine on coronary blood flow during percutaneous coronary intervention in patients with acute coronary syndromes

OBJECTIVES

To study the impact of injection of verapamil and adenosine in the coronary arteries on TIMI (Thrombolysis in Myocardial Infarction) frame count (TFC) after percutaneous coronary intervention (PCI) in patients with an acute coronary syndrome (ACS).

METHODS

Prospective, randomised, controlled study of the intracoronary administration of normal saline versus verapamil versus adenosine in patients undergoing PCI in the setting of an ACS, even when flow is visually established to be normal or near normal. Patients were randomised to receive verapamil (n = 49), adenosine (n = 51) or normal saline (n = 50) after PCI. Quantitative angiography, TIMI flow grade (TFG), TFC and myocardial blush grade were assessed before PCI, after PCI and after drugs were given. Wall motion index (WMI) was measured at days 1 and 30.

RESULTS

9 patients in the verapamil group developed transient heart block, not seen with adenosine (p <or= 0.001). Compared with saline, coronary flow measured by TFC improved significantly and WMI improved slightly but insignificantly in both the verapamil (TFC: p = 0.02; mean difference in improvement in WMI: 0.09, 95% confidence interval (CI) 0.015 to 0.17, p = 0.02) and the adenosine groups (TFC: p = 0.002; mean difference in improvement in WMI: 0.08, 95% CI 0.004 to 0.16, p = 0.04). The improvements in TFC and WMI did not differ significantly between the verapamil and the adenosine groups (TFC: p = 0.2; mean difference in improvement in WMI: 0.01, 95% CI -0.055 to 0.08, p = 0.7, respectively).

CONCLUSION

Administration of verapamil or adenosine significantly improves coronary flow and WMI after PCI in the setting of an ACS. Flow and WMI did not differ significantly between verapamil and adenosine but verapamil was associated with the development of transient heart block.

Dietary (n-3) fatty acids alter plasma fatty acids and leukotriene B synthesis by stimulated neutrophils from healthy geriatric Beagles

The study objective was to determine the effect of feeding food enriched in (n-3) fatty acids (FA) on plasma FA profiles and leukotriene B (LTB) synthesis by stimulated peripheral blood neutrophils from dogs. For 36 weeks, two groups of dogs (n = 5) were fed food that contained either a low ratio of (n-6)-(n-3) FA (1.31:1; fish oil-enriched food) or a high ratio of (n - 6)-(n-3) FA (40.6:1; corn oil-enriched food). Consumption of food enriched in fish oil resulted in higher plasma concentrations of eicosapentaenoic acid and docosahexaenoic acid and lower concentrations of arachidonic acid. Neutrophils from dogs fed fish oil-enriched food produced 7.6-fold more LTB(5)(P = 0.002), and the ratio of LTB(5)-LTB(4) concentrations was 8.3-fold higher (P < 0.001) compared with dogs fed corn oil-enriched food. Dietary FA can modulate leukotriene production by neutrophils in dogs, and suggests that foods enriched in (n-3) FA from fish oil may have value in the treatment of canine inflammatory diseases.

One year results of the Middlesbrough early revascularisation to limit infarction (MERLIN) trial

OBJECTIVE

To report one year results of the MERLIN (Middlesbrough early revascularisation to limit infarction) trial, a prospective randomised trial comparing the strategy of coronary angiography and urgent revascularisation with conservative treatment in patients with failed fibrinolysis complicating ST segment elevation myocardial infarction (STEMI). The 30 day results have recently been published. At the planning stage of the trial, it was determined that follow up of trial patients would continue annually to three years to determine whether late benefit occurred.

SUBJECTS

307 patients who received a fibrinolytic for STEMI but failed to reperfuse early according to previously described ECG criteria and did not develop cardiogenic shock.

METHODS

Patients were randomly assigned to receive either emergency coronary angiography with a view to proceeding to urgent revascularisation (rescue percutaneous coronary intervention (rPCI) arm) or continued medical treatment (conservative arm). The primary end point was all cause mortality at 30 days. The secondary end points included the composite end point of death, reinfarction, stroke, unplanned revascularisation, or heart failure at 30 days. The same end points were evaluated at one year and these results are presented.

RESULTS

All cause mortality at one year was similar in the conservative arm and the rPCI arm (13.0% v 14.4%, p = 0.7, risk difference (RD) -1.4%, 95% confidence interval (CI) -9.3 to 6.4). The incidence of the composite secondary end point of death, reinfarction, stroke, unplanned revascularisation, or heart failure was significantly higher in the conservative arm (57.8% v 43.1%, p = 0.01, RD 14.7%, 95% CI 3.5% to 25.5%). This was driven almost exclusively by a significantly higher incidence of subsequent unplanned revascularisation in the conservative arm (29.9% v 12.4%, p < 0.001, RD 17.5%, 95% CI 8.5% to 26.4%). Reinfarction and clinical heart failure were numerically, but not statistically, more common in the conservative arm (14.3% v 10.5%, p = 0.3, RD 3.8%, 95% CI -3.7 to 11.4, and 31.2% v 26.1%, p = 0.3, RD 5.0%, 95% CI -5.1 to 15.1). There was a strong trend towards fewer strokes in the conservative arm (1.3% v 5.2%, p = 0.06, RD -3.9%, 95% CI -8.9 to 0.06).

CONCLUSION

At one year of follow up, there was no survival advantage in the rPCI arm compared with the conservative arm. The incidence of the composite secondary end point was significantly lower in the rPCI arm, but this was driven almost entirely by a highly significant reduction in the incidence of further revascularisation.

Optimization of assay conditions for leukotriene B4 synthesis by neutrophils or platelets isolated from peripheral blood of monogastric animals

Neutrophils are involved in inflammation through leukotriene (LT) production. The predominant proinflammatory leukotriene released from neutrophils is LTB4, which serves as a biological marker of inflammation. The purpose of this study was to optimize the conditions ex vivo for LTB4 production by neutrophils from horses and dogs, and platelets from chickens. Optimal production of LTB4 was characterized by incubation time (2.5, 5, 10, 15 or 20 min), temperature (25 or 37 degrees C), and calcium ionophore A23187 concentration (0.1, 1, 10 or 20 microM). Incubation longer than 2.5 min did not increase production of LTB4 in chickens or horses; in dogs, incubation for 2.5 and 10 min resulted in the highest concentrations of LTB4 (P<or=0.05). In all species, incubation at 37 degrees C resulted in optimal LTB4 production (P<or=0.05). Production of LTB4 was highest when neutrophils or platelets were stimulated with 20 microM calcium ionophore in all species (P<or=0.05). These results indicate that neutrophils isolated from horses and dogs, and platelets isolated from chickens, are capable of producing LTB4. Optimum conditions for LTB4 production are similar in all three species.

Predictors of outcome after percutaneous treatment for cardiogenic shock

OBJECTIVES

To determine predictors of outcome after percutaneous coronary intervention (PCI) in patients with cardiogenic shock complicating acute myocardial infarction.

METHODS

Retrospective analysis of a cohort of 113 patients undergoing emergency coronary angiography and attempted PCI for cardiogenic shock complicating acute myocardial infarction in a regional cardiothoracic unit.

RESULTS

In-hospital mortality was 51% (58 patients). Adverse outcome was associated with previous myocardial infarction, age over 70 years, cardiogenic shock complicating failure to respond to thrombolytic treatment (failed thrombolysis), and multivessel coronary artery disease. Multivariate logistic regression analysis showed that the first three factors were independent predictors of in-hospital death with odds ratios of 5.21 (95% confidence interval (CI) 1.85 to 14.69), 4.02 (95% CI 1.14 to 14.12), and 3.78 (95% CI 1.43 to 9.96), respectively.

CONCLUSION

About 50% of patients with cardiogenic shock undergoing a strategy of urgent coronary angiography and PCI survive to hospital discharge. Survivors do well in the subsequent six months. Emergency PCI for cardiogenic shock reduces mortality from an expected 80% to about 50%. Clinical features can help determine which patients are most likely to gain from urgent coronary angiography and attempted PCI. Alternative strategies are needed to improve the outcome of patients who fare badly.

Physical versus chemical effects on bacterial and bromide transport as determined from on site sediment column pulse experiments

Twenty-eight bacterial and Br transport experiments were performed in the field to determine the effects of physical and chemical heterogeneity of the aquifer sediment. The experiments were performed using groundwater from two field locations to examine the effects of groundwater chemistry on transport. Groundwater was extracted from multilevel samplers and pumped through 7-cm-long columns of intact sediment or repacked sieved and coated or uncoated sediment from the underlying aquifer. Two bacterial strains, Comamonas sp. DA001 and Paenibacillus polymyxa FER-02, were injected along with Br into the influent end of columns to examine the effect of cell morphology and cell surface properties on bacterial transport. The effects of column sediment grain size and mineral coatings coupled with groundwater geochemistry were also investigated. Significant irreversible attachment of DA001 was observed in the Fe oxyhydroxide-coated columns, but only in the suboxic groundwater where the concentrations of dissolved organic carbon (DOC) were ca. 1 ppm. In the oxic groundwater where DOC was ca. 8 ppm, little attachment of DA001 to the Fe oxyhydroxide-coated columns was observed. This indicates that DOC can significantly reduce bacterial attachment due electrostatic interactions. The larger and more negatively charged FER-02 displayed increasing attachment with decreasing grain size regardless of DOC concentration, and modeling of FER-02 attachment revealed that the presence of Fe and Al coatings on the sediment also promoted attachment. Finally, the presence of Al coatings and Al containing minerals appeared to significantly retard the Br tracer regardless of the concentration of DOC. These findings suggest that DOC in shallow oxic groundwater aquifers can significantly enhance the transport of bacteria by reducing attachment to Fe, Mn and Al oxyhydroxides. This effect appears to be profound for weakly and strongly charged hydrophilic bacteria and may contribute to differences in observations between laboratory experiments versus field-scale investigations particularly if the groundwater pH remains subneutral and Fe oxyhydroxide phases exist. These observation validate the novel approach taken in the experiments outlined here of performing laboratory-scale experiments on site to facilitate the use of fresh groundwater and thus be more representative of in situ groundwater conditions.

Early and late reactions following the use of iopamidol 340, iomeprol 350 and iodixanol 320 in cardiac catheterization

GOAL

To investigate the incidence of early (< 24 hours) and late (> 24 hours to 7 days) reactions to 3 contrast agents commonly used in cardiac catheterization.

METHODS AND RESULTS

A total of 2,108 patients undergoing cardiac catheterization in a Regional Cardiothoracic Unit were randomly assigned to receive 1 of 3 commonly used contrast agents in a prospective, double-blind study. The contrast agents were iopamidol 340 (Niopam ), a nonionic monomer; iomeprol 350 (Iomeron ), a nonionic dimer; and iodixanol 320 (Visipaque ), a nonionic dimer. The main outcome measures were the incidence of early (< 24 hours) reactions following catheterization and the incidence of late (24 hours to 7 days) reactions. Early reactions, excluding patients with heat on left ventriculography as the sole symptom, were relatively common (7.4%), but there was no significant difference between the 3 agents (p = 0.35). Late skin reactions, excluding reactions solely at the site of the arterial puncture and continuations of early urticarial reactions, were also relatively common (5.4%), but the incidence differed between the 3 agents. Such reactions occurred in 2.7% of those receiving iopamidol 340 (Niopam ), 3.5% of those receiving iomeprol 350 (Iomeron ) and 10.4% of those receiving iodixanol 320 (Visipaque ) (p < 0.01).

CONCLUSION

The incidence of early adverse reactions is similar with these 3 contrast agents. However, late skin reactions are significantly more common with iodixanol 320 (Visipaque ) than with the other 2 agents. Although such reactions were rarely troublesome, patients should be advised accordingly.

Comparison of the temperature profile and pathological effect at unipolar, bipolar and phased radiofrequency current configurations

With a multi-electrode catheter, phased radiofrequency (RF) delivers current between each electrode and a backplate as well as between adjacent electrodes. This study compared the tissue heating and lesion dimensions created by phased and standard RF. Ablation was performed on the in vivo thigh muscles in 5 pigs. Six lesions were created on each thigh muscle using phase angle 0 degrees RF, 127 degrees RF, 180 degrees RF with and without a backplate, and standard RF in bipolar and sequential unipolar configurations. Two plunge needles, each with 6 thermocouples 1 mm apart, were inserted into the tissue with one needle beside an electrode and the other midway between electrodes for tissue temperature measurement. The 0 degrees RF created lower tissue temperatures and smaller lesions between electrodes than those beside electrode. With 127 degrees and 180 degrees RF, tissue temperature and lesion dimensions between electrodes were similar to beside electrode, while the 127 degrees RF created higher tissue temperature and deeper lesions than 180 degrees RF (both with and without a backplate) at both sites. Standard RF bipolar ablation created similar tissue temperatures and lesion depths at both sites, but required greater power than the 127 degrees RF. Standard RF sequential unipolar ablation created only a slight temperature increase and no lesions between electrodes 3 and 4. As judged by tissue temperature, lesion depth and uniformity, and RF power requirement, 127 degrees RF may be a better energy configuration for linear ablation than the other RF modalities tested.

Epidemiologic profiling: evaluating foodborne outbreaks for which no pathogen was isolated by routine laboratory testing: United States, 1982-9

The objective was to evaluate foodborne outbreaks of undetermined aetiology by comparing them to pathogen-specific epidemiologic profiles of laboratory-confirmed foodborne outbreaks. National foodborne outbreak data reported to CDC during 1982-9 were categorized by clinico-epidemiologic profiles based on incubation, duration, percent vomiting, fever and vomiting to fever ratio. From the pathogen-specific profiles, five syndromes were developed: a vomiting-toxin syndrome resembling Bacillus cereus and Staphylococcus aureus; a diarrhoea-toxin syndrome characteristic of Clostridium perfringens, a diarrhaeogenic Escherichia coli syndrome, a Norwalk-like virus syndrome, and a salmonella like syndrome. Of 712 outbreaks, 624 (87.6%) matched one of five syndromes; 340 (47.8%) matched the Norwalk-like syndrome and 83 (11.7%) matched the salmonella-like syndrome. After combining information on known pathogens and epidemiologic profiles, only 88 (12.4%) outbreaks remained unclassified. Norwalk-like virus outbreaks appear as common as salmonella-like outbreaks. We conclude that profiling can help classify outbreaks, guide investigations and direct laboratory testing to help detect new and emerging pathogens.

Costs and resources associated with the treatment of overactive bladder using retrospective medical care claims data

The objectives of this study were to determine age- and gender-specific drug treatment prevalence rates for overactive bladder (OAB), and to compare resource use and costs among MCO members receiving drug treatment for OAB. Administrative claims data from seven affiliated health plans were analyzed for 8,661 members with a diagnosis or treatment indicative of OAB during 1998. Resource use and associated costs were analyzed over a four-month follow-up. In 1998, the prevalence of OAB among plan members was 1.1%. Of the patients with OAB, 71% did not receive pharmacotherapy. After multivariate analysis, treatment with tolterodine, oxybutynin, or other OAB treatment did not significantly affect the percent change in total per patient per month (PPPM) costs compared with the group not receiving a pharmacologic agent. Although the adjusted percent change in PPPM pharmacy costs was significantly higher within the tolterodine group, medical and total PPPM costs were not.

Silent myocardial ischaemia in patients with proved coronary artery disease: a comparison of diabetic and non-diabetic patients

OBJECTIVE

To determine whether diabetic patients with coronary artery disease are more likely to experience silent myocardial ischaemia than subjects without diabetes.

SUBJECTS

Patients undergoing coronary angiography at a regional cardiothoracic unit, identified as having diabetes from the local district diabetic register/database.

DESIGN

The coronary angiograms and exercise treadmill tests of 100 diabetic and 100 non-diabetic patients who all had significant coronary artery disease and maximal effort exercise tests were reviewed. Patients were individually matched for age group, gender, severity of coronary artery disease, and indication for treadmill test.

OUTCOME MEASURES

Significant coronary artery disease was defined as a stenosis of greater than 50% diameter in at least one of the major coronary artery segments. Exercise tests were graded as positive if the electrocardiographic (ECG) recording showed planar or downsloping ST segment depression of > or = 1 mm in more than two leads at 80 ms post J-point or if there was a blood pressure fall > or = 10 mm Hg after an initial rise. A negative exercise test was defined as one in which the subject experienced no pain, had no ECG changes after maximal effort and had a normal blood pressure response. Subjects who did not experience any form of typical angina-type pain during a positive exercise test were defined as having an episode of silent ischaemia. Patients with symptomatic ischaemia were those who experienced typical angina-type pain with accompanying ST segment changes. Patients with a negative exercise test were defined as having "undetermined ischaemia". This category included all those without ECG evidence of myocardial ischaemia during the exercise test (with or without accompanying chest pain).

RESULTS

In the diabetic patients, 34% had ECG evidence of silent ischaemia on treadmill testing compared with only 19% of the non-diabetic controls (p < 0.02).

CONCLUSIONS

This study shows that diabetic patients with proved coronary artery disease have a higher risk of developing silent myocardial ischaemia during exercise than non-diabetic patients.

Transmembrane segment 11 of UhpT, the sugar phosphate carrier of Escherichia coli, is an alpha-helix that carries determinants of substrate selectivity

In Escherichia coli, transport of hexose 6-phosphates is mediated by the P(i)-linked antiport carrier, UhpT, a member of the major facilitator superfamily. We showed earlier that Lys(391), a member of an intrahelical salt bridge (Asp(388)/Lys(391)) in the eleventh transmembrane segment (TM11) of this transporter, can function as a determinant of substrate selectivity (Hall, J. A., Fann, M.-C., and Maloney, P. C. (1999) J. Biol. Chem. 274, 6148-6153). Here, we examine in detail the role of TM11 in setting substrate preference. Derivatives having an uncompensated cationic charge at either position 388 or 391 (the D388C, D388V, or D388K/K391C variants) are gain-of-function mutants in which phosphoenolpyruvate, not sugar 6-phosphate, is the preferred organic substrate. By contrast, when an uncompensated anionic charge is placed at position 388 (K391C), we observed behavior consistent with an increased preference for monovalent rather than divalent sugar 6-phosphate. Because positions 388 and 391 lie deep within the UhpT hydrophobic sector, these findings suggested that an extended length of TM11 may be accessible to external substrates and probes. To explore this issue, we used a panel of TM11 single cysteine variants to examine the transport of glucose 6-phosphate in the presence and absence of the membrane-impermeant, thiol-reactive agent p-chloromercuribenzosulfonate (PCMBS). Accessibility to PCMBS, together with the pattern of substrate protection against PCMBS inhibition, leads us to conclude that TM11 spans the membrane as an alpha-helix, with approximately two-thirds of its surface lining a substrate translocation pathway. We suggest that this feature is a general property of carrier proteins in the major facilitator superfamily and that for this reason residues in TM11 will serve to carry determinants of substrate selectivity.

The Dose of Case Management Interventions

Case management programs need to be evaluated for outcomes achievement and efficient use of resources. As a provider intervention, case management is interactional and situational. Little is known about how to measure the actual dose delivered in order to assess quality and manage outcomes. Case management is interdisciplinary, has identifiable dimensions, and serves as a practical example of conceptualizing and measuring the dosage of a provider's intervention. The basic elements of the dosage of an intervention are amount, frequency, duration, and breadth. A three-dimensional model illustrates dosage of case management.

Telephone management in substance abuse treatment

The purpose of this article is to describe the results of a clinical trial in which telephonic case management was evaluated as a supplement to substance abuse treatment. An interactive voice response system (IVR) was developed by the research team for use in the case management of randomly assigned participants in a clinical trial research project. The features of the software program facilitated a double caseload for the case manager as well as real-time data capture. At intake, no significant differences were found between participants in the telecommunication condition and the general project. Thus, the effectiveness of random assignment was supported. An IVR was useful for case management services, was less costly, and showed acceptability to clients. A reduction in time expenditure by using telecommunication occurred within three activity areas. Telecommunication facilitated client interaction and the use of case management, and it reduced provider time expenditure. As an alternative strategy, telecommunication case management can enhance cost effectiveness improvements.

Chemorepellent signaling through the PACAP/lysozyme receptor is mediated through cAMP and PKC in Tetrahymena thermophila

Pituitary adenylate cyclase-activating peptide and lysozyme are potent chemorepellents which act through the same receptor in Tetrahymena. Using in vivo behavioral studies, we have found that the pituitary adenylate cyclase-activating peptide/lysozyme receptor appears to signal through a G-protein pathway which is mediated through both adenosine 3'5'monophosphate and protein kinase C. Avoidance to pituitary adenylate cyclase-activating peptide and lysozyme is inhibited by the G-protein inhibitor, guanosine 5'-O-(2thiodiphosphate), the adenosine 3'5'monophate analog, Rp-adenosine-3', 5' cyclic monophosphorothioate, and the protein kinase C inhibitors, calphostin C and bisindolylmaleimide IV. A proposed model for signaling through the pituitary adenylate cyclase-activating peptide/lysozyme receptor is briefly outlined.

Early and late reactions after the use of iopamidol 340, ioxaglate 320, and iodixanol 320 in cardiac catheterization

BACKGROUND

Although modern contrast agents have tolerability superior to older agents, significant differences remain between the agents currently in use.

METHODS

To investigate the incidence of early (<24 hours) and late (>24 hours to 7 days) reactions to 3 contrast agents commonly used in cardiac catheterization, we performed a randomized, prospective, double-blind trial in which 2001 patients received one of the following agents: iopamidol 340, a nonionic monomer; ioxaglate 320, an ionic dimer; and iodixanol 320, a nonionic dimer. Possible reactions to contrast were recorded during the hospital admission and after discharge by means of a questionnaire, telephone follow-up, or both.

RESULTS

Early reactions occurred in 22.2% of those receiving ioxaglate, 7.6% of those receiving iodixanol, and 8.8% of those receiving iopamidol (P <.0001). Late skin reactions occurred in 12.2% of those receiving iodixanol, 4.3% of those receiving ioxaglate, and 4.2% of those receiving iopamidol (P <.0001).

CONCLUSIONS

The early side effect profile of certain ionic contrast agents suggests that these agents should no longer be used routinely in cardiac catheterization. The use of nonionic agents, however, is associated with late skin reactions, but there are notable differences between the monomeric and dimeric compounds. Although the skin reactions are generally benign, this is not always the case. Patients should be advised accordingly.

Crystal structures of the maltodextrin/maltose-binding protein complexed with reduced oligosaccharides: flexibility of tertiary structure and ligand binding

The structure of the maltodextrin or maltose-binding protein, an initial receptor for bacterial ABC-type active transport and chemotaxis, consists of two globular domains that are separated by a groove wherein the ligand is bound and enclosed by an inter-domain rotation. Here, we report the determination of the crystal structures of the protein complexed with reduced maltooligosaccharides (maltotriitol and maltotetraitol) in both the "closed" and "open" forms. Although these modified sugars bind to the receptor, they are not transported by the wild-type transporter. In the closed structures, the reduced sugars are buried in the groove and bound by both domains, one domain mainly by hydrogen-bonding interactions and the other domain primarily by non-polar interactions with aromatic side-chains. In the open structures, which abrogate both cellular activities of active transport and chemotaxis because of the large separation between the two domains, the sugars are bound almost exclusively to the domain rich in aromatic residues. The binding site for the open chain glucitol residue extends to a subsite that is distinct from those for the glucose residues that were uncovered in prior structural studies of the binding of active linear maltooligosaccharides. Occupation of this subsite may also account for the inability of the reduced oligosaccharides to be transported. The structures reported here, combined with those previously determined for several other complexes with active oligosaccharides in the closed form and with cyclodextrin in the open form, revealed at least four distinct modes of ligand binding but with only one being functionally active. This versatility reflects the flexibility of the protein, from very large motions of interdomain rotation to more localized side-chain conformational changes, and adaptation by the oligosaccharides as well.

Selective use of abciximab in coronary stenting: overall outcomes can still be equivalent to those in the EPISTENT treatment group

BACKGROUND: The EPISTENT trial reported improved early outcomes with routine use of abciximab after coronary stenting. Increasing use of stents means that routine abciximab adds significantly to costs of percutaneous coronary intervention (PCI). This paper reports the results of a protocol encouraging restriction of abciximab therapy to high-risk patients only. METHODS: Data were collected prospectively over a 34-month period for patients undergoing PCI with stenting. In addition to those who fulfilled criteria for inclusion in the EPISTENT trial, patients treated in the setting of acute myocardial infarction (AMI) were studied. Demographic data, procedural details and early clinical outcomes were recorded. RESULTS: Of 808 patients studied, 601 fulfilled EPISTENT inclusion criteria and comprised 367 patients (45%) treated for stable angina and 234 (30%) treated for unstable or post-infarct angina. The additional 207 patients (25%) were treated during AMI. The 808 patients received a total of 981 stents. Abciximab was given in only 88 cases (10.9%). Major adverse clinical events occurred in 39 patients (4.8%). CONCLUSION: Selective use of abciximab for patients undergoing coronary stenting can be associated with outcomes equivalent to those reported for routine use, but with significant cost savings.