Prediction of evolution toward brain death upon admission to ICU in comatose patients with spontaneous intracerebral hemorrhage using simple signs

The aim of the study was to identify the predictors of brain death (BD) upon admission to the intensive care unit (ICU) of comatose patients with spontaneous intracerebral hemorrhage (ICH). Patients admitted in our ICU from 2002 to 2010 for spontaneous ICH and placed under mechanical ventilation were retrospectively analyzed. Of the 72 patients, 49% evolved to BD, 39% died after withdrawal of life support, and 12% were discharged alive. The most discriminating characteristics to predict BD were included in two models; Model 1 contained ≥3 abolished brainstem responses [adjusted odds ratios (OR) = 8.4 (2.4, 29.1)] and the swirl sign on the baseline CT‐scan [adjusted OR = 5.0 (1.6, 15.9)] and Model 2 addressed the abolition of corneal reflexes [unilateral/bilateral: adjusted OR = 4.2 (0.9, 20.1)/8.8 (2.4, 32.3)] and the swirl sign on the baseline CT‐scan [adjusted OR = 6.2 (1.9, 20.0)]. Two scores predicting BD were created (sensitivity: 0.89 and 0.88, specificity: 0.68 and 0.65). Risk of evolution toward BD was classified as low (corneal reflexes present and no swirl sign), high (≥1 corneal reflexes abolished and swirl sign), and intermediate. Simple signs at ICU admission can predict BD in comatose patients with ICH and could increase the potential for organ donation.     

Thermal therapy, Part III: ablation techniques

Ablative treatments are gaining increasing attention as an alternative to standard surgical therapies, especially for patients with contraindication or those who refuse open surgery. Thermal ablation is used in clinical applications mainly for treating heart arrhythmias, benign prostate hyperplasia, and nonoperable liver tumors; there is also increasing application to other organ sites, including the kidney, lung, and brain. Potential benefits of thermal ablation include reduced morbidity and mortality in comparison with standard surgical resection and the ability to treat nonsurgical patients. The purpose of this review is to outline and discuss the engineering principles and biological responses by which thermal ablation techniques can provide elevation of temperature in organs within the human body. Because of the individual problems associated with each type of treatment, a wide range of ablation techniques have evolved including cryoablation as well as ultrasound, radiofrequency (RF), microwave, and laser ablation. Aspects of each ablation technique, including mechanisms of action, equipment required, selection of eligible patients, treatment techniques, and patient outcomes are presented, along with a discussion of limitations of the techniques and future research directions.     

Experimental model of congenital toxoplasmosis in guinea-pigs: use of quantitative and qualitative PCR for the study of maternofetal transmission

Maternofetal transmission of Toxoplasma gondii was assessed in pregnant guinea-pigs, with a gestational period of 65 +/- 5 days. A total of 56 female guinea pigs was infected by the intraperitoneal route (RH strain), by the oral or the intraperitoneal route (Prugniaud strain; PRU) or by the oral route (76K strain). Inoculation was performed 90 +/- 18 days or 30 +/- 9 days before the onset of gestation or 20 +/- 6 days or 40 +/- 6 days after. Gestational age was determined by a progesterone assay. Parasite loads (fetal brain and liver) were assessed by nested PCR and real-time PCR quantification on Light Cycler was performed with a SYBR Green I technique. The 76K strain appeared to be the most virulent in the model: the neonatal survival rate was 31%, in contrast to 53% and 68% for the PRU and RH strains, respectively. The percentage of survival of neonates for all strains taken together was lower after inoculation at 40 days' gestation (25%) than at 20 days' gestation (77%). Whatever the strain, maternofetal transmission determination was greater with nested PCR (54% for RH, 84% for PRU and 86% for 76K strains) than with real-time quantitative PCR (31% for RH, 66% for PRU and 76% for 76K strains). However, real-time quantitative PCR showed that neonatal parasite load was greater with the cystogenic strains (76K, PRU) and that high hepatic load (> 10000 parasites/g) was often associated with disease severity (11 of 12 cases). Therefore, this technique may provide an important element in understanding this congenital disease.     

Toxicovigilance: new biochemical tool used in sulfonylurea herbicides toxicology studies

In vitro toxic effects of sulfonylurea herbicides (thifensulfuron-methyl and metsulfuron-methyl) were evaluated according to a new protocol. Physiological conditions were reproduced in order to boost toxicovigilance. Sulfonylureas and their hydrolysis products were added to biological substrates such as urea, alanine, aspartic acid, alpha-ketoglutarate, oxaloacetate, pyruvate and then incubated with some specific enzymes. Addition of these sulfonylureas and their degradation products did not significantly change the enzymatic activity of the urease, aspartate-aminotransferase, glutamate dehydrogenase, malate dehydrogenase and lactate dehydrogenase. However, the acid hydrolysis products inhibited up to 95% of the activity of the alanine-aminotransferase at low concentrations (0.27 micromol L(-1)). Inhibition did not affect the mitochondrial aspartate-aminotransferase.     

Canadian multicenter laboratory study for standardized second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis

The purpose of this study was to establish a standardized protocol for second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis using the Bactec MGIT 960 system in Canadian laboratories. Four Canadian public health laboratories compared the susceptibility testing results of 9 second-line antimicrobials between the Bactec 460 and Bactec MGIT 960 systems. Based on the data generated, we have established that the Bactec MGIT 960 system provides results comparable to those obtained with the previous Bactec 460 method. The critical concentrations established for the testing of the antimicrobials used are as follows: amikacin, 1 μg/ml; capreomycin, 2.5 μg/ml; ethionamide, 5 μg/ml; kanamycin, 2.5 μg/ml; linezolid, 1 μg/ml; moxifloxacin, 0.25 μg/ml; ofloxacin, 2 μg/ml; p-aminosalicylic acid, 4 μg/ml; rifabutin, 0.5 μg/ml.     

Bicentric Evaluation of Six Anti-Toxoplasma Immunoglobulin G (IgG) Automated Immunoassays and Comparison to the Toxo II IgG Western Blot

A comparative study of the Toxoplasma IgG_I and IgG_II Access (Access I and II, respectively; Beckman Coulter Inc.), AxSYM Toxo IgG (AxSYM; Abbott Diagnostics), Vidas Toxo IgG (Vidas; bioMerieux, Marcy l''Etoile, France), Immulite Toxo IgG (Immulite; Siemens Healthcare Diagnostics Inc.), and Modular Toxo IgG (Modular; Roche Diagnostics, Basel, Switzerland) tests was done with 406 consecutive serum samples. The Toxo II IgG Western blot (LDBio, Lyon, France) was used as a reference technique in the case of intertechnique discordance. Of the 406 serum samples tested, the results for 35 were discordant by the different techniques. Using the 175 serum samples with positive results, we evaluated the standardization of the titrations obtained (in IU/ml); the medians (second quartiles) obtained were 9.1 IU/ml for the AxSYM test, 21 IU/ml for the Access I test, 25.7 IU/ml for the Access II test, 32 IU/ml for the Vidas test, 34.6 IU/ml for the Immulite test, and 248 IU/ml for the Modular test. For all the immunoassays tested, the following relative sensitivity and specificity values were found: 89.7 to 100% for the Access II test, 89.7 to 99.6% for the Immulite test, 90.2 to 99.6% for the AxSYM test, 91.4 to 99.6% for the Vidas test, 94.8 to 99.6% for the Access I test, and 98.3 to 98.7% for the Modular test. Among the 406 serum samples, we did not find any false-positive values by two different tests for the same serum sample. Except for the Modular test, which prioritized sensitivity, it appears that the positive cutoff values suggested by the pharmaceutical companies are very high (either for economical or for safety reasons). This led to imperfect sensitivity, a large number of unnecessary serological follow-ups of pregnant women, and difficulty in determining the serological status of immunosuppressed individuals.Toxoplasmosis, caused by Toxoplasma gondii, is widespread in humans and warm-blooded animals. Although it is usually asymptomatic in immunocompetent humans, toxoplasmosis may cause severe disorders in pregnant women, because of the high risk of transplacental transmission and the occurrence of abortion or multiple congenital lesions in the fetus, and in immunocompromised individuals (5, 9).Life-threatening reactivation of a previous infection is commonly observed in cases of severe immunodeficiency (human immunodeficiency virus-infected patients, organ and hematopoietic stem cell transplant patients). For these patients, the detection of Toxoplasma-specific antibodies showing serological reactivation or primary infection is therefore essential for the appropriate diagnosis and prevention of severe toxoplasmosis (2, 7).The follow-up of patients with obstetric toxoplasmosis mainly depends on the detection of antitoxoplasma-specific immunoglobulin M (IgM) and IgG antibodies (14, 16, 18). The presence of toxoplasma-specific IgM at the time of the first blood test is a cause for concern. The presence of toxoplasma-specific IgG without IgM permits confirmation of the immunization of the patients and thus allows unnecessary and expensive follow-up to be avoided.For both obstetric follow-up and diagnosis in immunocompromised patients, tests for IgG are crucial. Since the 1980s, toxoplasma-specific IgG assays have been standardized by different generations of World Health Organization (WHO) standards (15), and test results have been reported in international units per milliliter (IU/ml). The dye test (DT), first described by Sabin and Feldman 60 years ago, is still the reference method for the serodiagnosis of toxoplasmosis. However, this test uses live Toxoplasma gondii and is now used in only a few laboratories (13). A good alternative, the test Toxo II IgG Western blot (LDBio, Lyon, France) has been proposed to be a confirmatory technique by Franck et al. (6). The results of this test appear to be consistent with those of DT, with a specificity of 100% and a sensitivity of 99.2%. Thus, this immunoblotting technique can be used as a very reliable and easy confirmatory test in laboratories where DT cannot be implemented.Despite the international standardization and the availability of a reference (or confirmatory) test, automated immunoassays frequently show discordance and moderate degrees of correlation (6, 12). A comparison of six random-access immunoassays (that report IgG levels in IU/ml) and the Toxo II IgG Western blot (LDBio) as a confirmatory technique was undertaken to review the analytical performance characteristics and the degree of standardization of the tests.