Comparison between radiometry and spectrophotometry for the determination of angiotensin-converting enzyme activity in cerebrospinal fluid.

Determination of angiotensin-converting enzyme (ACE) activity in cerebrospinal fluid (CSF) can help for establishing the diagnosis of neurosarcoidosis. We investigated the performance characteristics of two assays for ACE determination in 57 CSF, radiometry with [glycine-1-14C] benzoyl-L-histidyl-L-leucine and spectrophotometry with furylacryloyl-phenylalanyl-L-glycyl-L-glycine (FAPGG) as substrates. We compared both kinetic assays to an ELISA specific for human ACE.

[Measurement of angiotensin-I-converting enzyme in the blood: help for method validation].

Blood angiotensin-converting enzyme (ACE) assay is now realized by the determination of enzyme activity on synthetic substrate, mostly furylacryloyl-phenylalanyl-L-glycyl-L-glycine (FAPGG). The matrix can be serum or heparin-plasma, with or without a separator; the assay developed on serum or plasma is not adapted to other matrix such as cerebrospinal fluid where the ACE activity is much lower. This assay has been adapted on a number of automated biochemistry analyzers with the specifications of the supplier of reagents, sometimes with modification of volumes or times for analysis.

Multi-centre evaluation of recent troponin assays for the diagnosis of NSTEMI.

Objectives: We aimed to compare the use of nine different cardiac troponin (cTn) assays (2 cTnT and 7 cTnI) for the diagnosis of NSTEMI in a single multi-centre population.

Design And Methods: One hundred and fifty-eight patients were included (mean age 60 years, SD 17 years), including 23 patients (14%) with NSTEMI.

Results: The analytical comparison highlighted a large heterogeneity of cTn assays, as reflected by percentages of patients with detectable cTn, correlation coefficients, Passing-Bablok comparisons and concordance coefficients.

Search for biomarkers of neurosarcoidosis by proteomic analysis of cerebrospinal fluid.

Sarcoidosis is a systemic granulomatous disease, which mostly affects lung. Central nervous system can be affected causing a neurosarcoidosis in 5 to 15% of all sarcoidosis patients. The definitive diagnosis is established on histological examination of brain granulomas.

Angiotensin-converting enzyme insertion/deletion gene polymorphism in a Tunisian healthy and acute myocardial infarction population.

Introduction: The role of the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene (ACE) on acute myocardial infarction (AMI) is controversial.

Objectives: To assess the effect of the ACE I/D polymorphism on AMI compared with the healthy controls and its relationship with serum ACE activity in a Tunisian population.

Design And Methods: A total of 119 patients with AMI were compared with 238 healthy controls from the same geographical area.

False elevation of blood lactate reveals ethylene glycol poisoning.

Ethylene glycol poisoning is a medical emergency. Making a definitive diagnosis is challenging because few institutions have timely access to direct measurement of ethylene glycol. After ingestion, primary metabolism of ethylene glycol takes place in the liver, leading to glycolic acid and glyoxylic acid.

Point-of-care testing: false elevation of cardiac troponin I assayed in the emergency department.

In October 2007, an 18-year-old woman with no cardiac history was admitted to the emergency department for a major epigastric pain. The chest pain led to assay cardiac troponin I (cTnI) with the emergency department point-of-care testing analyzer (Stratus CS), which disclosed a value of 0.70 ng/mL, discordant with the atypical clinical presentation and the noncontributive electrocardiography.

Evaluation of the GEM Premier 4000: a compact blood gas CO-Oximeter and electrolyte analyzer for point-of-care and laboratory testing.

Background: GEM Premier 4000 (Instrumentation Laboratory), a new blood gas/CO-Oximeter/hematocrit/electrolyte/glucose/lactate analyzer was evaluated. The only reagents required were disposable cartridges (GEM Premier 4000 PAK comprise all components necessary for analysis, including quality controls).

Methods: The evaluation was performed in two laboratories according to the Valtec protocol guidelines.

[Angiotensin I-converting enzyme in cerebrospinal fluid and neurosarcoidosis].

Sarcoidosis is a disease of unknown aetiology. This granulomatous disease is essentially localized in lung and skin, but many other localizations are possible, such as in nervous system. Sometimes the neurological involvement is alone leading to a differential diagnosis from other neurological diseases.

Evaluation of the blood gas analyzer Gem PREMIER 3000.

During the past few decades, new technologies have allowed the fabrication of miniaturized sensors and the development of analyzers well designed for point-of-care testing (POCT). They combined the ease-of-use and portability required for POC with the accuracy and the reliability of traditional systems. Instrumentation Laboratory introduced the GEM Premier 3000, a compact and portable system to rapidly analyze pH, pCO2, PO2, Ca2+, Na2+, K+, lactate, glucose and hematocrit, from 135 microl of whole blood with a simple component: a cartridge, the GEM Premier Pak.

Evaluation of Stratus CS stat fluorimetric analyser for measurement of cardiac markers Troponin I (cTnI), creatine kinase MB (CK-MB), and myoglobin.

Myoglobin, CK-MB, and Troponin I (cTnI) are cardiac muscle necrosis markers that are useful for detecting acute myocardial infarction (AMI). The Stratus CS (Dade Behring, Inc.) is a discrete fluorimetric immunoassay analyser designed for the determination of the three cardiac markers from a single sample of whole blood or plasma.

Anticancer drugs induce necrosis of human endothelial cells involving both oncosis and apoptosis.

The endothelium is the first physiological barrier between blood and tissues and can be injured by physical or chemical stress, particularly by the drugs used in cancer therapy. We found that four anticancer agents: etoposide, doxorubicin, bleomycin and paclitaxel induced apoptosis in human umbilical vein endothelial cells (HUVECs) (as judged by DNA fragmentation) with a time- and concentration-dependent decrease in bcl-2 protein but without the involvement of p53. As revealed by immunoblotting, bax protein was expressed in HUVECs treated with 1 mg/ml etoposide whereas bcl-2 protein disappeared.

Mixed-type inhibition of pulmonary angiotensin I-converting enzyme by captopril, enalaprilat and ramiprilat.

We have compared at the enzymological level pulmonary angiotensin I-converting enzymes (ACE) purified to electrophoretic homogeneity from four mammalians species: pig, rat, monkey and human. Using both substrates hippuryl-histidyl-leucine and furylacryloyl-phenylalanyl-glycyl-glycine in steady-state conditions, all the ACEs exhibited Michaelis kinetics with identical Michaelis constants, maximal velocities, optimal pH and optimal activating chloride-concentrations. The apparent inhibitory constant was higher for Captopril than for Enalaprilat and even more so for Ramiprilat irrespective of the origin of ACE and the substrate used.

Plasma concentration, kinetic constants, and gene polymorphism of angiotensin I-converting enzyme in centenarians.

We have determined serum activity and kinetic constants of angiotensin I-converting enzyme (ACE), parallel to an insertion/deletion (I/D) polymorphism in its gene, in French centenarians and controls 20-70 years of age because this enzyme could have an impact on cardiovascular risk, and thus on longevity. Both the ACE D allele and ACE D/D genotype were more frequent in centenarians in comparison with controls, without sex-related differences nor significant correlation with a cardiovascular pathology. In centenarians, I/D polymorphism was correlated with circulating ACE activity (D/D genotype, 89.

Structural and biological roles of glycosylations in pulmonary angiotensin I-converting enzyme.

We enzymatically deglycosylated pig lung angiotensin I-converting enzyme (ACE) to study the involvement of its glycanic chains in its physicochemical and catalytic properties. The effects of endoglycosidases F2 and H, and of N-glycanase were assessed by ACE mobility in SDS-PAGE. N-Glycanase only was completely effective with or without previous denaturation, leading to a shift in ACE M(r) from 172 to 135 kDa; endoglycosidase F2 produced the same shift but only without previous denaturation.

Cytotoxicity of amiodarone in cultured human endothelial cells.

As damage to the pulmonary vascular endothelium may be responsible for the lung toxicity of amiodarone, we evaluated the cytolytic toxicity of the drug in cultures of endothelial cells. Cells were cultured from human umbilical cord veins. Amiodarone caused a vacuolization of the cells with liberation of both lactate dehydrogenase (LDH) and angiotensin-converting enzyme (ACE) in the culture medium.

Physiochemical and immunological comparisons between angiotensin I-converting enzymes purified from different mammalian species.

Angiotensin I-converting enzyme (ACE) was purified from lungs of pig, rat, monkey and human for comparison of its physicochemical, enzymatic and immunological properties. The protocol involved three chromatographic steps after detergent extraction, i.e.

Plasma fibronectin and angiotensin-converting enzyme: markers of primary pulmonary injury in burn patients.

Plasma fibronectin (FBN) and angiotensin I-converting enzyme (ACE) were prospectively measured in 50 burn patients from the day of admission to day 28 after the trauma with the aim of finding biochemical markers of pulmonary injury by smoke inhalation. Patients were divided into three groups on the basis of fiberoptic bronchoscopy results (group I: healthy lungs; group II: burned lungs; group III: infected lungs). A decrease in FBN concentrations was observed in the three groups but was larger in group II than in the other groups, especially at day 2 (P < 0.

Angiotensin-converting enzyme: clinical applications and laboratory investigations on serum and other biological fluids.

Angiotensin I-converting enzyme (ACE) is a peptidyldipeptide hydrolase that is located mainly on the luminal surface of vascular endothelial cells but also in cells derived from the monocyte-macrophage system. Physiologically, ACE is a key enzyme in the renin-angiotensin system, converting angiotensin I into the potent vasopressor angiotensin II and also inactivating the vasodilator bradykinin. Increased serum ACE activity (SACE) has been reported in pathologies involving a stimulation of the monocytic cell line, primarily granulomatous diseases.

A reliable radiometric assay for the determination of angiotensin I-converting enzyme activity in urine.

We present a radiometric assay for the determination of urinary angiotensin-converting enzyme activity, using benzoyl-[1-14C]glycyl-L-histidyl-L-leucine as the substrate. An optimal pH of 8.3, an optimal chloride concentration of 0.

Serum angiotensin-converting enzyme in healthy and sarcoidotic children: comparison with the reference interval for adults.

Angiotensin-converting enzyme (ACE) was measured in serum of 187 healthy children between the ages six months and 18 years. Results were pooled for five-year age intervals and compared with the reference values for adults that we previously determined [Clin Chem 1986;32:884-6). Results for each age group were also studied as a function of sex.

Clinical reliability of measured and calculated oxygen parameters in surgical patients: influence of hyperventilation.

The acid-base and oxygen status were assessed in patients undergoing abdominal surgery. We determined the measured and calculated parameters described by Siggaard-Andersen in arterial and mixed venous blood before, during and after a controlled hyperventilation. In these dynamic conditions, the mixed venous calculated p50 showed the most interesting variations.