Effectiveness of a diagnostic algorithm combining clinical probability, D-dimer testing, and computed tomography in patients with suspected pulmonary embolism in an emergency department

OBJECTIVE

The aim of our study was to assess the clinical effectiveness of a simplified algorithm using the Wells clinical decision rule, D-dimer testing, and computed tomography (CT) in patients with suspected pulmonary embolism (PE) in an Emergency Department (ED).

METHODS

Patients with clinically suspected PE from the Emergency Department were included from May 2007 through December 2008. Clinical probability was assessed using the Wells clinical decision rule and a VIDAS D-dimer assay was used to measure D-dimer concentration. Patients were categorized as "pulmonary embolism unlikely" or "pulmonary embolism likely" using the dichotomized version of the Wells clinical decision rule. Pulmonary embolism was considered excluded in patients with unlikely probability and normal D-dimer test (< 500 ng/ml). All other patients underwent CT, and pulmonary embolism was considered present or excluded based on the results. Anticoagulants were withheld from patients classified as excluded, and all patients were followed up for 3 months.

RESULTS

241 patients were included in the study. The prevalence of PE in the entire population was 23.6%. The combination of unlikely probability using the dichotomized Wells clinical decision rule and a normal D-dimer level occurred in 23.6%, thus making CT unnecessary. During the followup period, no thromboembolic events were recorded and there were no deaths related to venous thromboembolic disease (3-month thromboembolic risk 0% [95% CI, 0%-8%]).

CONCLUSIONS

In this study we have confirmed the effectiveness of a diagnostic management strategy using a simple clinical decision rule, D-dimer testing, and CT in the evaluation and management of patients with clinically suspected pulmonary embolism.

Evaluation of a lime-mediated sewage sludge stabilisation process. Product characterisation and technological validation for its use in the cement industry

This paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the sludge, raised the temperature of the mix to 80-100°C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the sludge. Process mass and energy balances were determined. Neutral, a white powder consisting of portlandite (49.8%), calcite (16.6%), inorganic oxides (13.4%) and organic matter and moisture (20.2%), proved to be technologically apt for inclusion as a component in cement raw mixes. In this study, it was used instead of limestone in raw mixes clinkerised at 1400, 1450 and 1500°C. These raw meals exhibited greater reactivity at high temperatures than the limestone product and their calcination at 1500°C yielded clinker containing over 75% calcium silicates, the key phases in Portland clinker. Finally, the two types of raw meal (Neutral and limestone) were observed to exhibit similar mineralogy and crystal size and distribution.

Are fungi important for breaking seed dormancy in desert species? Experimental evidence in Opuntia streptacantha (Cactaceae)

Seeds of Opuntia spp. have physiological dormancy; they need a period of after-ripening to break dormancy, and the embryos have low growth potential. We evaluated the combined effects of seed age and presence of fungi on the testa on germination of Opuntia streptacantha, an abundant species in the Chihuahuan Desert (Mexico), assuming that older seeds have broken seed dormancy and fungi can reduce mechanical resistance to germination. In a preliminary experiment, we found no germination of 9-year-old (1998) and freshly collected (2007) seeds. However, we obtained 67% and 27% germination from 9-year-old and fresh non-sterilized seeds, respectively, and found fungi growing on the testa of all germinated seeds. Two fungal strains were isolated and identified using ribosomal internal transcribed spacer (ITS) sequence analysis: Penicillium chrysogenum and Phoma sp. In a second experiment, we inoculated seeds with strains of P. chrysogenum and Phoma sp., as well as Trichoderma koningii and binucleate Rhizoctonia (Gto17S2), to evaluate their ability to break seed dormancy. Seeds inoculated with P. chrysogenum, Phoma sp. and T. koningii had higher germination than controls for both seed ages, but germination was higher in older seeds. Scanning electron microscopy showed that these fungi eroded the funiculus, reducing its resistance. Binucleate Rhizoctonia did not lead to germination and controls had almost no germination. Our results strongly indicate that fungi are involved in breaking seed dormancy of O. streptacantha, and that the effect of fungi on seeds is species-specific.

Automated pattern-guided principal component analysis vs expert-based immunophenotypic classification of B-cell chronic lymphoproliferative disorders: a step forward in the standardization of clinical immunophenotyping

Immunophenotypic characterization of B-cell chronic lymphoproliferative disorders (B-CLPD) is becoming increasingly complex due to usage of progressively larger panels of reagents and a high number of World Health Organization (WHO) entities. Typically, data analysis is performed separately for each stained aliquot of a sample; subsequently, an expert interprets the overall immunophenotypic profile (IP) of neoplastic B-cells and assigns it to specific diagnostic categories. We constructed a principal component analysis (PCA)-based tool to guide immunophenotypic classification of B-CLPD. Three reference groups of immunophenotypic data files-B-cell chronic lymphocytic leukemias (B-CLL; n = 10), mantle cell (MCL; n = 10) and follicular lymphomas (FL; n = 10)--were built. Subsequently, each of the 175 cases studied was evaluated and assigned to either one of the three reference groups or to none of them (other B-CLPD). Most cases (89%) were correctly assigned to their corresponding WHO diagnostic group with overall positive and negative predictive values of 89 and 96%, respectively. The efficiency of the PCA-based approach was particularly high among typical B-CLL, MCL and FL vs other B-CLPD cases. In summary, PCA-guided immunophenotypic classification of B-CLPD is a promising tool for standardized interpretation of tumor IP, their classification into well-defined entities and comprehensive evaluation of antibody panels.

Recycling of ash from mezcal industry: a renewable source of lime

Agave bagasse is a byproduct generated in the mezcal industry. Normally it is burned to reduce its volume, then a byproduct is generated in the form of residual ash, which can contaminate the water in rivers and lakes near the production places called "mezcaleras". This report details measurements of the Agave Salmiana fiber transformation after the burning process. The wasted ash was heated at 950°C, and then hydrolyzed. The compounds were indentified using the X-ray diffraction. The images obtained by scanning electron microscope showed all the morphological transformations of the lime through the whole process. Thermal, elemental and morphological characterization of the agave bagasse were done. Experiments showed that 16% of ash was produced in the burning process of agave bagasse (450°C), and 66% of the ash remains after heating (950°C) in the form of calcium oxide. The results show an important renewable source of calcium compounds, due to the high production of agave based beverages in México.

Characterization of norovirus-associated traveler's diarrhea

BACKGROUND

Traveler's diarrhea is the most common medical complaint of international visitors to developing regions. Previous findings suggested that noroviruses (NoVs) are an underappreciated cause of traveler's diarrhea. METHODS. In the present study, we sought to define the presence of NoVs in 320 acute diarrheic stool samples collected from 299 US students who traveled to Guadalajara, Cuernavaca, or Puerto Vallarta, Mexico, during the period from 2007 through 2008. Conventional and quantitative real-time polymerase chain reaction assays were used to detect and determine NoV loads in stool samples. NoV strains were characterized by purification of viral RNA followed by sequencing of the viral capsid protein 1 gene. Sequences were compared using multiple sequence alignment, and phylogenetic trees were generated to evaluate the evolutionary relatedness of the viral strains associated with cases of traveler's diarrhea.

RESULTS

NoV RNA was detected in 30 (9.4%) of 320 samples. Twelve strains belonged to genogroup I, and 18 strains belonged to genogroup II. NoV prevalence was higher in the winter season than in the summer season (23% vs 7%, respectively; P = .001). The cDNA viral loads of genogroup I viruses were found to be 500-fold higher than those of genogroup II strains. Phylogenetic analysis revealed a diverse population of NoV strains over different locations and years.

CONCLUSIONS

NoV strains are important causes of traveler's diarrhea in Mexico, especially during the wintertime, and US students in Mexico may represent a suitable group for future NoV vaccine efficacy trials.

A probabilistic approach for the evaluation of minimal residual disease by multiparameter flow cytometry in leukemic B-cell chronic lymphoproliferative disorders

Multiparameter flow cytometry has become an essential tool for monitoring response to therapy in hematological malignancies, including B-cell chronic lymphoproliferative disorders (B-CLPD). However, depending on the expertise of the operator minimal residual disease (MRD) can be misidentified, given that data analysis is based on the definition of expert-based bidimensional plots, where an operator selects the subpopulations of interest. Here, we propose and evaluate a probabilistic approach based on pattern classification tools and the Bayes theorem, for automated analysis of flow cytometry data from a group of 50 B-CLPD versus normal peripheral blood B-cells under MRD conditions, with the aim of reducing operator-associated subjectivity. The proposed approach provided a tool for MRD detection in B-CLPD by flow cytometry with a sensitivity of < or =8 x 10(-5) (median of < or =2 x 10(-7)). Furthermore, in 86% of B-CLPD cases tested, no events corresponding to normal B-cells were wrongly identified as belonging to the neoplastic B-cell population at a level of < or =10(-7). Thus, this approach based on the search for minimal numbers of neoplastic B-cells similar to those detected at diagnosis could potentially be applied with both a high sensitivity and specificity to investigate for the presence of MRD in virtually all B-CLPD. Further studies evaluating its efficiency in larger series of patients, where reactive conditions and non-neoplastic disorders are also included, are required to confirm these results.

Ethnic differences in HLA antigens in Chilean donors and recipients: data from the National Renal Transplantation Program

To describe HLA antigen distribution, looking for possible markers of renal disease in Mapuche and non-Mapuche people in the renal transplantation program, we reviewed data from 1297 histocompatibility studies of the Chilean national renal transplantation program (421 donors and 876 recipients), performed between 2000 and 2005. Mapuche people were classified according to their family surnames. The most frequent antigens found among the total Chilean population were A2 (48%), A19 (33%), B16 (33%), B35 (26%), DR4 (38%), and DR6 (28%), without significant differences between donors and recipients. Among the 114 individuals (9%) classified as Mapuche, the most frequent antigens were A28 (49%), A2 (44%), B16 (63%), B35 (24%), DR4 (48%), and DR8 (30%), with A28/B16/DR4 as the most common haplotype. In contrast, A28, B16, DR4, and DR8 were significantly more frequent in Mapuche compared with non-Mapuche people. B8 was significantly more frequent in Mapuche recipients than in non-Mapuche recipients and Mapuche donors. The higher frequency of some HLA antigens in Mapuche people was confirmed, possibly corresponding to ethnic markers. The special concentration of B8 among Mapuche recipients might represent a genetic factor predisposing to chronic renal disease in this human group.

Patients' perception and effectiveness of a treatment containing enfuvirtide when used in HIV-infected patients without very advanced disease

PURPOSE

To evaluate the satisfaction with self-injected enfuvirtide (ENF) and the clinical outcome of HIV-infected patients without very advanced disease.

METHOD

ESPPE is a multicenter observational study that included 103 evaluated patients showing baseline characteristics predictive of positive outcome: CD4 >100 cells/mm3, viral load (VL) <100,000 copies/mL, previous treatment with a maximum of 10 antiretroviral drugs, and concomitant use of 2 active drugs. By using validated surveys, patients were questioned 6 months after the prescription of ENF about their quality of life (QoL) and acceptance of self-injections and adherence to the treatment.

RESULTS

At 6 months, the mean CD4 increase was 121 cells/mm3 (p < .05) and 65% (intent-to-treat, ENF stopped=failure) had VL <50 copies/mL (p < .001). Fourteen patients discontinued the treatment, mostly due to intolerance (6). The majority (>89%) assessed all items relating QoL as "excellent," "very good," or "good." The treatment satisfaction index on a visual analog scale scored a median of 8.1 out of 10; when participants were asked about the interference of injections on their daily activities, 87% answered "never" or "only sometimes."

CONCLUSION

Effectiveness and patients' perception about ENF remain good when ENF was used in patients without very advanced disease. QoL was not impaired after ENF use.

The activation of adenylate cyclase by cholera toxin: possible interaction with the nucleotide regulatory site

The application of cholera toxin to intact cells causes a stimulation of adenylate cyclase activity. The effect is characterized by a lag period followed by a progressive rise in enzyme activity over several hours. Only a few minutes' exposure to the toxin is required to produce effects lasting over several days. Stimulation of adenylate cyclase by cholera toxin in broken cell preparations requires the presence of nicotinamide-adenine dinucleotide (NAD) and an unidentified component of the cytosol. Guanyl nucleotides and certain non-hydrolysable analogues of guanosine triphosphate also stimulate adenylate cyclase. Stimulation by the analogues results in a highly activated enzyme which has characterisitcs similar to those of adenylate cyclase after stimulation by cholera toxin. Thus the stimulation is irreversible, the enzyme may be "solubilized" by non-ionic detergents in the activated state, and responses to certain hormones are enhanced. Therefore the possibility exists that cholera toxin acts on the guanyl nucleotide regulatory protein of the adenylate cyclase complex. In exploring this possibility it was found pretreatment with cholera toxin not only blocked the stimulatory effect of subsequently added guanylylimidodi-phosphate (GppNHp) but that the latter reduced the stimulation by toxin. Similarly, pretreatment with GppNHp blocked the effect of cholera toxin. The similarities in the effects of cholera toxin and GppNHp, together with the mutual interference of their activities, suggests that cholera toxin acts at the same regulatory site at which guanyl nucleotides exert their effects on adenylate cyclase.

Rapid evolution of congenital hepatic fibrosis after liver transplantation for acute liver failure: the potential role of extrahepatic factors

A 9-year-old male underwent deceased donor liver transplantation for idiopathic fulminant hepatic failure. In the postoperative period, a review of perioperative biopsies of the donor liver revealed mild features of congenital hepatic fibrosis. Over the ensuing year, the recipient developed severe complications of congenital hepatic fibrosis including multiple episodes of cholangitis and progressive portal hypertension. After a second transplant, the patient had no further episodes of cholangitis and/or features of portal hypertension. Examination of the explanted liver revealed remarkable progression of the congenital hepatic fibrosis, suggesting that the phenotype of this disease may be dependent in part on extrahepatic factors.

Selective 5HT2A and 5HT6 receptor antagonists promote sleep in rats

STUDY OBJECTIVES

Serotonin (5-HT) has long been implicated in the control of sleep and wakefulness. This study evaluated the hypnotic efficacy of the 5-HT6 antagonist RO4368554 (RO) and the 5-HT2A receptor antagonist MDL100907 (MDL) relative to zolpidem.

DESIGN

A randomized, repeated-measures design was utilized in which Wistar rats received intraperitoneal injections of RO (1.0, 3.0, and 10 mg/kg), MDL (0.1, 1.0 and 3.0 mg/kg), zolpidem (10 mg/kg), or vehicle in the middle of the dark (active) period. Electroencephalogram, electromyogram, body temperature (Tb) and locomotor activity were analyzed for 6 hours after injection.

MEASUREMENTS AND RESULTS

RO, MDL, and zolpidem all produced significant increases in sleep and decreases in waking, compared with vehicle control. All 3 doses of MDL produced more consolidated sleep, increased non-rapid eye movement sleep (NREM) sleep, and increased electroencephalographic delta power during NREM sleep. The highest dose of RO (10.0 mg/kg) produced significant increases in sleep and decreases in waking during hour 2 following dosing. These increases in sleep duration were associated with greater delta power during NREM sleep. ZO Zolpidem induced sleep with the shortest latency and significantly increased NREM sleep and delta power but also suppressed rapid eye movement sleep sleep; in contrast, neither RO nor MDL affected rapid eye movement sleep. Whereas RO did not affect Tb, both zolpidem and MDL reduced Tb relative to vehicle-injected controls.

CONCLUSIONS

These results support a role for 5-HT2A receptor modulation in NREM sleep and suggest a previously unrecognized role for 5-HT6 receptors in sleep-wake regulation.

Diabetes team consultation: impact on length of stay of diabetic patients admitted to a short-stay unit

OBJECTIVE

To assess the impact of endocrinology team consultation on hospital stay and clinical outcomes of diabetic patients admitted with a primary non-diabetes-related diagnosis in a short stay unit (SSU).

METHODS

Patients admitted to the SSU between 2001 and 2005. Between 2001 and 2003 there was no endocrinology team consultation available and the management of hyperglycemia was handled by the SSU team alone. From 2003 until 2005 an endocrinology team was in charge of diabetes care. We compared in both periods: prevalence of diabetes, length of hospital stay, mortality, early readmissions and number of patients requiring conventional hospitalization.

RESULTS

In period 2001-2003, 1023 patients were admitted, among which 212 were diabetic (20.7%). Over the years 2003-2005, 892 patients were hospitalized, 223 were diabetic (25%). Clinical characteristics of diabetic patients from both periods were comparable, but glycaemia at admission was higher on the second period (217 mg/dl versus 198 mg/dl). The length of stay of diabetic patients in the second period decreased from 5.49 to 4.90 days. There were no significant differences in mortality (1.4% versus 0.4%) or in early re-admissions among the two periods.

CONCLUSIONS

The intervention of a diabetes team diminished the average length of stay of diabetic patients.

A randomized trial comparing the efficacy and tolerability of two HAART strategies at two years in antiretroviral naive patients

BACKGROUND

The use of HAART combining 2 nucleoside analogues reverse transcriptase inhibitors (NRTIs) plus one protease inhibitor (PI) or 2 NRTIs + 1 non-nucleoside reverse transcriptase inhibitor (NNRTI) has shown comparable efficacy. The study was designed to compare long term (2 years) effectiveness of two antiretroviral (ARV) treatment strategies in patients not previously treated: starting with a nelfinavir based HAART switching to nevirapine in case of failure or side effects or the reverse sequence.

METHODS

This multicenter, randomized, open label clinical trial enrolled ARV-naïve HIV patients with CD4 counts below 500 cells/mm3. They were randomly assigned to start ddI + d4T + nelfinavir (switching to ZDV + 3TC + NEV in case of failure or toxicity) (PI-NEV arm) or ddI + d4T + nevirapine, switching to ZDV + 3TC + NFV in case of failure or toxicity (NEV-PI arm). The primary study endpoint was the Kaplan-Meier estimates of the time to failure after switching to second regimen if necessary (considering failure as two consecutive plasma HIV-1 RNA determinations above 200 copies/mL, death, a new category C event or toxicity leading to treatment discontinuation of the second regimen) after a minimum follow-up of two years.

RESULTS

A total of 137 patients were evaluable (67 and 70 in the PI-NEV and NEV-PI arms respectively). Baseline characteristics did not differ among groups. Kaplan-Meier estimates of time to failure did not show differences between the two arms neither in the on-treatment (OT) analysis (log rank test, p = 0.81) nor in the intent-to-treat (ITT) analysis (p = 0.58). At 24 months, the estimated proportion of patients free of failure were 72% and 66% respectively in the PI-NEV and NEV-PI arms OT analysis (p = 0.54) and 73% and 64% in the PI-NEV and NEV-PI arms in the ITT analysis (p = 0.49). The difference in the median in CD4+ lymphocyte count at 24 months was not significantly different in the two groups: 393 and 307 CD4 cells/mm3 in the PI-NEV and NEV-PI arms respectively (p = 0.167). The incidence of adverse events (AEs) in the two arms was very similar: 50 (75%) in the PI-NEV and 54 (70%) in the NEV-PI group, as it was for grade 3-4 AEs leading to drug switching.

CONCLUSION

At two years both treatments strategies (PI-NEV vs NEV-PI) had a high and comparable efficacy and were generally well tolerated.

Electrocardiographic characterization of embryonic zebrafish

The zebrafish (Danio rerio) has emerged as one of the primary experimental models of developmental cardiovascular research. Recent progress in flow visualization techniques along with the existing genetic map of the species has made zebrafish amenable to a variety of experiments relating cardiac developmental structure and function. One essential tool in establishing the proper functioning of the heart is the electrocardiogram (ECG). This study presents a methodology whereby the ECGs of embryonic zebrafish could be used in assessing the electrophysiological consequences of genetically-, mechanically-, or pharmacokinetically-induced cardiac perturbations. Five day post-fertilization (dpf) embryos produced repeating bimodal ECGs with clearly distinguished atrial (P) and ventricular (R) depolarization waves. P-R intervals along with P-P intervals are cited.