Complete preferences over health states: a reply to the paper by Shiell et al.
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Adult↗
Biomedical subjects
A Oliver
Publications and source records attributed to A Oliver.
Improved dose homogeneity to the intact breast using three-dimensional treatment planning: technical considerations.
The current consensus is that breast-conservative treatment is superior to mastectomy because it provides survival equivalent to total mastectomy and axillary dissection while preserving the breast. This technique still has several technical issues that can adversely influence the successful outcome of breast-conservative treatment. Specifically, dose coverage and homogeneity must be maintained throughout the breast while reducing the hot-volume magnitude and normal tissue complications. A random retrospective three-dimensional treatment-planning study was conducted using computed tomography scans of 20 female patients with early-stage breast cancer. Two- and three-dimensional homogenous and heterogeneous treatment planning was conducted using all possible hard-wedge combinations and effective photon energies, with the goal of reducing the hot volumes in the breast below 110 percent of the prescribed dose. The hard-wedge combination that minimized the hot volumes uses either 15-degree wedges on the medial and lateral beams or a 30-degree wedge on the medial beam and a 15-degree wedge on the lateral beam. For patients with bridge distances less than 20 cm, this wedge combination reduces the hot volumes below 110 percent of the prescribed dose. For patients with bridge distances greater than 20 cm, low- and high-energy photon beams must be mixed to lower the maximum dose below 110 percent of the prescribed dose. The hot volumes in the breasts of 20 random patients was reduced below 110 percent of the prescribed dose without a significant reduction in tumor coverage.
Algorithms↗
Pneumococcal psoas abscess: report of two cases.
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Cefotaxime↗
D-Dimer is an early diagnostic marker of coronary ischemia in patients with chest pain.
BACKGROUND: Chest pain is a frequent symptom in the emergency department and often presents a diagnostic challenge. Because coronary thrombosis is a hallmark of acute ischemic syndromes, the substrates of the coagulation and fibrinolysis cascades may be markers of coronary ischemia. The objective of this study was to determine the diagnostic value of several hemostatic markers in patients presenting to the emergency department (ED) with chest pain syndromes. METHODS: Two hundred fifty-seven consecutive patients with acute chest pain were studied in this prospective study conducted in an urban ED. D-Dimer levels were measured at admission to the ED in all patients. We also measured thrombin-antithrombin complexes, prothrombin fragment 1+2, activated factor VII, and fibrinogen. We used regression analysis to estimate the likelihood of myocardial infarction and the diagnostic value of D-dimer. RESULTS: D-Dimer and fibrinogen levels were significantly higher in patients with acute ischemic events (myocardial infarction and unstable angina) than in nonischemic patients (P <.01 and P =.02, respectively). The other hemostatic markers were not significantly elevated in patients with ischemic events. D-Dimer level >500 microg/L had an independent diagnostic value for myocardial infarction and increased the diagnostic sensitivity of the electrocardiogram and history from 73% to 92%. CONCLUSION: D-Dimer, an expression of ongoing thrombus formation and lysis, is a marker of substantial incremental value for the early diagnosis of acute coronary syndromes presenting with chest pain. It adds independent information to the traditional assessment for myocardial infarction. D-Dimer can be incorporated into clinical decision models in the ED.
Adult↗
Outbreak of a multiresistant Klebsiella pneumoniae strain in an intensive care unit: antibiotic use as risk factor for colonization and infection.
An observational study was undertaken to describe a nosocomial outbreak caused by multiresistant Klebsiella pneumoniae (MRKP). Ten patients in the pediatric intensive care unit (ICU) at a hospital in Madrid were colonized by or infected with MRKP from October 1997 to April 1998. Thirty-two patients with MRKP-negative surveillance cultures who were admitted to the ICU during the outbreak period were selected as control patients. Random amplified polymorphic DNA analysis of MRKP isolates revealed patterns that were indistinguishable from each other. After identification of colonized patients by surveillance cultures and implementation of standard and contact precautions, the outbreak was controlled. An age <12 weeks (odds ratio [OR], 13.1) and previous treatment with third-generation cephalosporins and aminoglycosides (OR, 31.2) were independently associated with MRKP colonization and/or infection. Individual exposure to antibiotics, irrespective of other clinical determinants, is a risk factor for MRKP acquisition. Screening high-risk patients during outbreaks and reducing the use of third-generation cephalosporins and aminoglycosides contribute to the control of these epidemics.
Anti-Bacterial Agents↗
Evolution of leukotriene B4, peptide leukotrienes, and interleukin-8 plasma concentrations in patients at risk of acute respiratory distress syndrome and with acute respiratory distress syndrome: mortality prognostic study.
OBJECTIVE: To compare the evolution of plasma concentrations of leukotriene (LT) B4, LTC4, LTD4, and interleukin (IL)-8 in patients with acute respiratory distress syndrome (ARDS) and in patients at risk of ARDS and to assess the value of these mediators in predicting mortality rate from ARDS. DESIGN: A case-control study comparing ARDS patients and patients at risk of ARDS as well as survivors and nonsurvivors with ARDS. SETTING: Hospital intensive care unit, laboratory, and department of hematology. PATIENTS: Twenty-one patients with ARDS and 14 patients at risk of ARDS. INTERVENTION: Arterial blood samples were collected on days 0, 1, and 5 after admission to the intensive care unit. MEASUREMENTS AND MAIN RESULTS: LTs were extracted, separated by high-pressure liquid chromatography and quantified by enzyme immunoassay. IL-8 was analyzed by ELISA. Plasma concentrations of LTB4 and LTC4 plus LTD4 were significantly higher in ARDS patients than in patients at risk of ARDS during the first 24 hrs. Concentrations of IL-8 were also higher in ARDS patients than in patients at risk throughout the study, although the differences between the two groups were only significant on day 5. Only the plasma concentration of LTB4 on day 1 was a marker of ARDS (72.2% sensitivity, 84.6% specificity). A logistic regression analysis showed that LTB4 and IL-8, on day 1, were markers of mortality rate in patients with ARDS (70.0% sensitivity, 87.5% specificity). CONCLUSIONS: LTs are elevated during the early phases of ARDS, whereas IL-8 increases throughout the study. The evaluation of LTB4 and IL-8 may be useful prognostic indices in patients with early phase ARDS after admission to the intensive care unit.
Biomarkers↗
OXA-24, a novel class D beta-lactamase with carbapenemase activity in an Acinetobacter baumannii clinical strain.
Acinetobacter baumannii RYC 52763/97, a clinical isolate involved in a prolonged nosocomial outbreak at our hospital, was resistant to all beta-lactams tested, including imipenem and meropenem, which had MICs of 128 and 256 microg/ml, respectively. This strain synthesized three beta-lactamases: a plasmid-mediated TEM-1 beta-lactamase (pI 5.4), an AmpC-type chromosomal cephalosporinase (pI 9.4), and a novel, presumptively chromosomally mediated OXA-related enzyme (pI 9.0) named OXA-24. After cloning and sequencing, the deduced amino acid sequence of the OXA-24 beta-lactamase showed 40% homology with the OXA-10 (PSE-2) and OXA-7 beta-lactamases, 39% homology with the OXA-11 and OXA-5 enzymes, and 33% homology with the LCR-1 beta-lactamase. The amino acid sequence of the OXA-24 beta-lactamase contained the STFK motif found in serine beta-lactamases, but the typical class D triad KTG was replaced by KSG and the motif YGN was replaced by FGN. The OXA-24 beta-lactamase hydrolyzed benzylpenicillin and cephaloridine but lacked activity against oxacillin, cloxacillin, and methicillin. The enzymatic activity was inhibited by chloride ions and by tazobactam (50% inhibitory concentration [IC(50)], 0.5 microM), sulbactam (IC(50), 40 microM), and clavulanic acid (IC(50), 50 microM). Carbapenem MICs for an Escherichia coli transformant (pBMB-1) expressing the cloned OXA-24 enzyme had a fourfold increase. Relative V(max)/K(m) values of 13 and 6 were obtained with imipenem and meropenem, respectively, and a positive microbiological assay result with imipenem was obtained with a purified enzymatic extract of this transformant strain. Therefore, we consider this new beta-lactamase to be involved in the carbapenem resistance of A. baumannii RYC 52763/97.
Acinetobacter↗
Molecular characterization of FOX-4, a new AmpC-type plasmid-mediated beta-lactamase from an Escherichia coli strain isolated in Spain.
A clinical strain of Escherichia coli (Ec GCE) displayed resistance to cefoxitin, cefotetan, cefotaxime, and ceftazidime. Susceptibility was not restored by the addition of clavulanic acid. Two beta-lactamases with apparent pIs of 5.4 and 6.4 were identified; the beta-lactamase with a pI of 6.4 was transferred by conjugation and associated with a 40-kb plasmid. Analysis of the nucleotide sequence showed a new ampC beta-lactamase gene that is closely related to those encoding the FOX-3, FOX-2, and FOX-1 beta-lactamases but whose product has four novel amino acid mutations, at positions 11 (M-->T), 43 (A-->E), 233 (V-->A), and 280 (Y-->H). This first cephamycinase from Spain was named FOX-4.
Amino Acid Sequence↗
Evaluation of the Wider system, a new computer-assisted image-processing device for bacterial identification and susceptibility testing.
The Wider system is a newly developed computer-assisted image-processing device for both bacterial identification and antimicrobial susceptibility testing. It has been adapted to be able to read and interpret commercial MicroScan panels. Two hundred forty-four fresh consecutive clinical isolates (138 isolates of the family Enterobacteriaceae, 25 nonfermentative gram-negative rods [NFGNRs], and 81 gram-positive cocci) were tested. In addition, 100 enterobacterial strains with known beta-lactam resistance mechanisms (22 strains with chromosomal AmpC beta-lactamase, 8 strains with chromosomal class A beta-lactamase, 21 broad-spectrum and IRT beta-lactamase-producing strains, 41 extended-spectrum beta-lactamase-producing strains, and 8 permeability mutants) were tested. API galleries and National Committee for Clinical Laboratory Standards (NCCLS) microdilution methods were used as reference methods. The Wider system correctly identified 97.5% of the clinical isolates at the species level. Overall essential agreement (+/-1 log(2) dilution for 3,719 organism-antimicrobial drug combinations) was 95.6% (isolates of the family Enterobacteriaceae, 96.6%; NFGNRs, 88.0%; gram-positive cocci, 95.6%). The lowest essential agreement was observed with Enterobacteriaceae versus imipenem (84.0%), NFGNR versus piperacillin (88.0%) and cefepime (88.0%), and gram-positive isolates versus penicillin (80.4%). The category error rate (NCCLS criteria) was 4.2% (2.0% very major errors, 0.6% major errors, and 1. 5% minor errors). Essential agreement and interpretive error rates for eight beta-lactam antibiotics against isolates of the family Enterobacteriaceae with known beta-lactam resistance mechanisms were 94.8 and 5.4%, respectively. Interestingly, the very major error rate was only 0.8%. Minor errors (3.6%) were mainly observed with amoxicillin-clavulanate and cefepime against extended-spectrum beta-lactamase-producing isolates. The Wider system is a new reliable tool which applies the image-processing technology to the reading of commercial trays for both bacterial identification and susceptibility testing.
Anti-Bacterial Agents↗
Platelet function during cardiopulmonary bypass not changed by two different doses of aprotinin.
BACKGROUND AND OBJECTIVE: Bleeding is one of the major complications of cardiopulmonary bypass (CBP) during cardiac surgery. A platelet function defect seems to be the main cause of the hemostatic problems associated with CBP. Controversial results have been reported concerning the possible protective mechanism of action of aprotinin on platelets. DESIGN AND METHODS: In this study we investigated the effect of two different dosages of aprotinin (high and pump-prime-only dose) on platelet reactivity in vitro and adhesion, activation and aggregation receptors on the platelet surface. RESULTS: The results obtained from 53 patients undergoing CBP showed a significantly deficient platelet aggregation in response to agonist in all groups without differences between aprotinin treated or not treated patients. No changes in platelet surface expression of glycoprotein (GP) IIb-IIIa, GPIb, GPIV and P-selectin, were observed during CBP between patients treated with aprotinin or not. INTERPRETATION AND CONCLUSIONS: These data suggest that inadequate platelet function induced by CBP is not a defect intrinsic to the platelet. We conclude that the hemostatic effect of aprotinin, regardless of the dose employed, is not mediated by protection of platelet function.
Adult↗
The effect of two different doses of aprotinin on hemostasis in cardiopulmonary bypass surgery: similar transfusion requirements and blood loss.
BACKGROUND AND OBJECTIVES: Various dosages of aprotinin have proven to be effective in reducing blood loss and allogeneic transfusion requirements in cardiopulmonary bypass surgery, despite the controversy surrounding the precise hemostatic mechanisms of this drug. The aim of our prospective, randomized, double-blind study was to assess differences in blood loss and transfusion requirements and the effect of two dosages of aprotinin on hemostatic activation. DESIGN AND METHODS: Patients undergoing coronary artery bypass grafting received high-dose aprotinin (n=28), pump-prime-only (PPO) aprotinin (n=28), or placebo (n=28). RESULTS: The high-dose and the PPO groups had a significantly lower blood loss (985 mL [95%CI 845-1,102] and 1,255 mL, [95% CI 1,025-1,406], respectively) than the placebo group (1,416 mL, 95%CI 1,248-1,612]. Transfusion requirements were lower in the aprotinin-treated groups than in the patients receiving placebo (21 units and 15 units in the high and low-dose groups vs 59 units in placebo group). As far as concerns parameters of thrombin generation, the aprotinin groups showed a significant reduction of F1+2 prothrombin fragment but not of thrombin-antithrombin complexes. There were higher levels of natural anticoagulants, i.e. antithrombin, protein C and protein S, in the high-dose aprotinin group. As regards fibrinolysis parameters, D-dimer was lower in the aprotinin groups, and the levels of alpha2-antiplasmin and plasmin-alpha2-antiplasmin complexes were raised. In summary, both dosages of aprotinin were equally effective in reducing blood loss and transfusion requirements. There was a lower activation of coagulation and fibrinolysis in cardiopulmonary bypass patients treated with aprotinin: the levels of natural anticoagulants were less decreased in the high-dose group. No differences in thrombotic complications were observed between aprotinin groups. INTERPRETATION AND CONCLUSIONS: Our study shows that both dosages of aprotinin are safe and effective in reducing transfusion requirements. Considering the difference in cost of using a low-dose or high-dose schedule, the former should be recommended for patients undergoing cardiopulmonary bypass surgery.
Adult↗
Restriction fragment length polymorphism of the L-myc gene is not a prognostic factor in bladder cancer patients.
The L-myc restriction fragment length polymorphism has been suggested to be of prognostic significance in some types of primary tumours. We examined the prognostic and susceptibility significance of the L-myc genotype in a group of 98 bladder cancer patients. The L-myc genotype did not correlate with any pathologic parameter and does not offer any clinical utility in patients with bladder cancer.
Adolescent↗
Ampicillin-sulbactam and amoxicillin-clavulanate susceptibility testing of Escherichia coli isolates with different beta-lactam resistance phenotypes.
The activities of ampicillin-sulbactam and amoxicillin-clavulanate were studied with 100 selected clinical Escherichia coli isolates with different beta-lactam susceptibility phenotypes by standard agar dilution and disk diffusion techniques and with a commercial microdilution system (PASCO). A fixed ratio (2:1) and a fixed concentration (clavulanate, 2 and 4 micrograms/ml; sulbactam, 8 micrograms/ml) were used in the agar dilution technique. The resistance frequencies for amoxicillin-clavulanate with different techniques were as follows: fixed ratio agar dilution, 12%; fixed concentration 4-micrograms/ml agar dilution, 17%; fixed ratio microdilution, 9%; and disk diffusion, 9%. Marked discrepancies were found when these results were compared with those obtained with ampicillin-sulbactam (26 to 52% resistance), showing that susceptibility to amoxicillin-clavulanic acid cannot be predicted by testing the isolate against ampicillin-sulbactam. Interestingly, the discrimination between susceptible and intermediate isolates was better achieved with 4 micrograms of clavulanate per ml than with the fixed ratio. In contrast, amoxicillin susceptibility was not sufficiently restored when 2 micrograms of clavulanate per ml was used, particularly in moderate (mean beta-lactamase activity, 50.8 mU/mg of protein) and high-level (215 mU/mg) TEM-1 beta-lactamase producer isolates. Four micrograms of clavulanate per milliliter could be a reasonable alternative to the 2:1 fixed ratio, because most high-level beta-lactamase-hyperproducing isolates would be categorized as nonsusceptible, and low- and moderate-level beta-lactamase-producing isolates would be categorized as nonresistant. This approach cannot be applied to sulbactam, either with the fixed 2:1 ratio or with the 8-micrograms/ml fixed concentration, because many low-level beta-lactamase-producing isolates would be classified in the resistant category. These findings call for a review of breakpoints for beta-lactam-beta-lactamase inhibitors combinations.
Amoxicillin↗
Patients with venous thromboembolism have a lower APC response than controls. Should this be regarded as a continuous risk factor for venous thrombosis?
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Adult↗
Elevated levels of plasmin-alpha2 antiplasmin complexes in unstable angina.
The evidence of elevated levels of several biochemical markers of prothrombotic state in patients with unstable angina suggests that thrombus formation and lysis play a pivotal role in acute coronary syndromes. The clinical syndrome of unstable angina encompasses a variety of clinical presentations of transient episodes of myocardial ischemia. This study was designed to assess plasmin generation in different settings of unstable angina. Evidence of plasmin generation in patients with unstable angina was measured by circulating plasmin-alpha2 antiplasmin complexes (PAP). A second objective was to identify whether PAP levels had a prognostic value to predict outcome. Eighty-five patients admitted to the coronary care unit for unstable angina were classified into three groups. Group A included 26 patients with postinfarction angina; group B comprised 26 patients with new onset angina; and group C included 33 patients with crescendo angina. Mean PAP levels were higher in the three groups compared to healthy controls. A significant correlation was found between levels of PAP and D-dimer, particularly in postinfarction angina (r = 0.6; p <0.0005). This trial adds new insights into the pathophysiology of unstable angina. It demonstrates that plasmin is generated in the different settings of unstable angina but particularly in postinfarction angina patients where a fibrin-rich thrombus is responsible of the symptoms. However, in this series PAP levels do not predict an uneventful outcome neither in the acute phase nor at long term (6 months).
Aged↗
Increased risk of venous thrombosis in carriers of natural anticoagulant deficiencies. Results of the family studies of the Spanish Multicenter Study on Thrombophilia (EMET study).
Several studies have demonstrated a higher risk of thrombosis in carriers of anticoagulant deficiencies than in non-deficient individuals from families with thrombophilia. The prevalences in Spain were established in a multicenter study (the EMET study) and all the deficient individuals were invited to recruit all available family members to be screened for the same deficiency in order to establish the risk of thrombosis in deficient individuals. Five-hundred-and-eighty-three individuals from 114 families with natural anticoagulant deficiencies were analysed. Propositi and relatives with a history of thrombosis were asked about the localization and the age at the first episode and whether or not it was spontaneous. Three families with antithrombin deficiency, 35 with protein C, 60 with protein S, four with plasminogen, four with heparin cofactor II, seven with combined deficiencies and one family with dysfibrinogenemia were included in the analysis. The risk of thrombosis was increased for individuals deficient in antithrombin (adjusted odds ratio 21.23; 95% confidence interval 5.71-78.94), protein C (adjusted odds ratio 12.62; 95% confidence interval 4.75-33.51), protein S type I (adjusted odds ratio 19.95; 95% confidence interval 7.40-53.82), protein S type III (adjusted odds ratio 8.11; 95% confidence interval 2.66-21.99) or in protein C plus protein S (adjusted odds ratio 8.99; 95% confidence interval 2.79-28.93), but not for those deficient in plasminogen or heparin cofactor II. The thrombosis-free survival was shortened for deficient individuals in antithrombin (median 30 years), protein C (median 46 years), protein S type-I (median 48 years), protein S type III (median 61 years) and combined protein C and S (median 40 years). In conclusion, individuals carrying anticoagulant deficiencies have an increased risk of thrombosis, especially those with antithrombin, protein C or type I protein S deficiencies.
Adult↗
The prothrombin 20210A allele is the most prevalent genetic risk factor for venous thromboembolism in the Spanish population.
We investigated the prevalence of the new recently reported mutation in the prothrombin gene (20210 A) in a sample of 116 unrelated patients with venous thromboembolism. We found 20 heterozygous carriers (17.2%, CI 95% 10.4-21.1). In comparison, we observed 13 carriers among 201 healthy unmatched controls (6.5%, CI 3.5-10.8). The 20210 A mutation seems to increase the risk of venous thrombosis 3-fold (odds ratio 3.1, 95% CI 1.4-6.6). Considering only patients with a first event (n = 62) the OR was 2.0 (p = 0.18, NS) while those with recurrent events (n = 54) showed an OR of 5.9 (95% CI 2.5-14.4). A majority of heterozygous patients (55%) presented a second thrombophilic factor and 60% of affected females had their first event before 30 years of age, while on oral contraceptive treatment. The prevalence found in this study for healthy people is the highest reported to date. The 20210 A variant appears to be the most prevalent genetic risk factor among patients with thrombosis in our geographical area.
Adolescent↗