[Apolipoprotein E and bleomycin hydrolase. Polymorphisms: association with neurodegenerative diseases]. / Maladies neurodégénératives et polymorphisme des gènes de l'apolipoprotéine E et de la bléomycine hydrolase.

Several studies indicate a possible association between different genes and chronic neurodegenerative diseases including Alzheimer's disease (DTA). To further investigate, we have analyzed association between the apolipoprotein E (apo E) and bleomycin hydrolase (BH) polymorphisms and three groups of elderly patients: control subjects (T) (n = 68), late-onset sporadic DTA patients (DTAst) (n = 65) and other non vascular neurodegerative diseases (MNDA) (n = 52). Apo E-epsilon4 and BH-G alleles frequencies (%) are: 8.2 (T), 31.5 (DTAst), 16.4 (MNDA) and 41.4 (T), 35.6 (DTAst). No association has been observed between carrying the G allele and DTA in epsilon4 negative subjects but, our data have confirmed the earlier reports: carrying the epsilon4 allele is a dose-dependent risk factor for the DTAst (OR: 6.0, IC 95 %: 2.6-13.7) and decrease the age of symptom onset (p < 0.005). They have also suggested that apo E genotyping may be of interest to perform differential diagnosis of neurodegenerative diseases in elderly subjects.

[Molecular genetics: pre- and post-analytic "best practices"]. / Génétique moléculaire: les << bonnes pratiques>> pré-et postanalytieques.

Medical prescriptions for molecular genetic analyses are not yet very common in general practice, neverless they are becoming more and more frequent, and therefore it is more difficult to deal with them in part because of the recent french rules. Laboratory managers are supposed to be able to deal with such requests. This document, describing good laboratory practices, has been elaborated by members of the group "molecular genetics" from the "College National de Biochimie des Hôpitaux", providing details about: assessment of the prescriptions, including patient's consent, choice of the executing laboratory, specimen transmission, assessment and control of clinical and biological data, results transmission, confidentiality, archiving system. Such recommendations should facilitate exchanges with specialized laboratories, being specifically approved for practicing such analyses. The authors draw the attention of laboratory managers to the specificities of such requests.

[Update of a selected technique for uric acid determination in plasma and serum. Experimental study and value of derivative spectrophotometry]. / Mise au point d'une technique sélectionnée de dosage de l'acide urique dans le plasma et le sérum. Etude expérimentale et intérêt de la spectrophotométrie dérivée.

A critical study of the candidate reference method for evaluation of uric acid in plasma proposed by the American Association of Clinical Chemistry is followed by testing in six laboratories. The dispersion of results is wide (CV greater than 5%). The importance of turbidity remaining after the deproteinization by trichloracetic acid is clearly demonstrated. This turbidity is really not reproducible from an operation to another one on the same serum. It is very likely responsible of the great dispersion of the results. After that, other deproteinization methods are tried. Ultrafiltration and ultracentrifugation give both defect errors because uric acid is in part bound to proteins. So it is necessary to find another technic which cancels the effects of turbidity on the absorbance readings in the ultra-violet domain. Experimental studies showed that uric acid may be evaluated with a good accuracy by derivative spectrophotometry, in lipid solutions as well as in cloudy ones. Turbidity was created by intralipid suspension additions. Various parameters hitting the method were examined (linearity, smoothing window...), taking as criterion the measure of overloaded serums at different levels. At last, the method is successfully transferred in several sites. In the case of blood serum, the respective influences of derivation and of repetition of final centrifugations are studied in order to estimate the effect of remaining turbidity. By the use of derivative spectrophotometry the improvement of the method of evaluation of uric acid proposed by A.A.C.C. is very noticeable; it reduces the variation coefficient between sites to less than 2%.

[A recommended method for determination of uric acid in serum]. / Méthode recommandée pour le dosage de l'acide urique dans le sérum.

SFBC work group on uric acid propose a method for evaluation in blood serum which is modeled on the one defined by American Association for Clinical Chemistry. Serum is deproteinized by trichoracetic acid and the supernatant, buffered to pH 8.5, is submitted to uricase action. The disappearing of the strong band of uric acid in UV is measured by derivative spectrophotometry; this procedure vanished the effect of trouble which remains in the supernatant. This spectrophotometric technic permit to reach, in multiple sites, a variation coefficient near of 1 p. cent.

[Lipids and lipoproteins in atherosclerotic arteriopathy of the legs. Unusual study of very low density lipoproteins]. / Lipides et lipoprotéines dans l'artériopathie athéroscléreuse des membres inférieurs. Etude particulière des lipoprotéines de très faible densité.

Lipids, apolipoproteins A1 and B and lipoproteins were studied in 49 patients with peripheral arterial disease and in 26 control patients. The observed hypertriglyceridemia was related to the elevation of the VLDL lipid mass; no alteration in their structure could be shown. The origin of this VLDL excess was discussed especially the role of tobacco and genetic.

[Value of the cytologic and biochemical study of alveolar lavage fluid in the evaluation of the developmental ability of sarcoidosis]. / Intérêt de l'étude cytologique et biochimique du liquide de lavage alvéolaire dans l'appréciation de l'évolutivité de la sarcoïdose.

To study indicators of disease activity in sarcoidosis, bronchoalveolar lavage (BAL) and serum angiotensin-converting enzyme (SACE) measurement were performed in 39 patients with active sarcoidosis and in 13 patients with inactive sarcoidosis. All patients were non-smokers. Results were compared to those from 9 non-smoking controls and 20 patients with non-granulomatous interstitial lung disease. Lymphocyte counts, IgG concentrations and the IgG/K ratio were high in BAL fluid specimens from patients with active sarcoidosis, indicating a relationship between cellular and humoral immunity. Conversely, specimens from inactive sarcoidosis patients showed supranormal lymphocyte counts with IgG levels and a IgG/K ratio that did not differ significantly from those in controls or patients with interstitial lung disease (p greater than 0,05). Patients with active sarcoidosis that abated after 6 to 12 months had an initial lymphocytosis of 28.7% and a IgG/K ratio under 170 mg/mmol. We conclude that IgG concentrations and the IgG/K ratio are better discriminators between active and non-active or nearly resolved disease than lymphocyte counts. SACE assay is not sufficiently discriminative.

The elimination of inorganic fluoride after enflurane anesthesia--transitory action on parathyroid tissue.

Enflurane has been introduced as a potentially useful clinical anesthetic compound. Its administration is followed by elevations of blood and urine concentrations of inorganic fluoride, whose nephrotoxicity has been previously described. Although the action of this element on the skeleton is well documented when ingested orally, its influence has not yet been investigated when it results from the metabolism of fluorinated anesthetic drugs. The present study examines renal function and calcium-phosphorus balance after administration of low concentration of enflurane. Twenty-one patients of both sexes undergoing minor surgery were selected. A statistical analysis of biologic items determined before and after anesthesia showed no significant variations of parameters involved in renal function. On the contrary, it was shown that biodegradation of enflurane was responsible for a significant change in blood and urine phosphorus concentrations. Moreover variations in phosphorus clearance suggested a transitory hypersecretion of parathyroid hormones, probably related to inorganic fluoride metabolism. Such a result is interesting because of the low blood concentration of inorganic fluoride and its transitory character.

Multivariate analysis of clinical and biological data in cirrhotic patients: application to prognosis.

One hundred and thirty-one patients underwent clinical and biological investigation with the following determinations performed on the same day; presence or absence of ascites, icterus and/or encephalopathy, coagulation study, biochemical determinations including albumin, transferrin and immunoglobulins immunoassays. The principal component analysis of biological data showed two sets of highly representative and inversely correlated data; one included coagulation tests, albumin and transferrin, and the other included immunoglobulin A/transferrin ratio, immunoglobulin A and total bilirubin. Clinical and biological data were computed using discriminant analysis between dead and survivors. Six parameters were then selected (total bilirubin, encephalopathy, factor V, AST, antithrombin III and transferrin) giving a correct prognosis in 81.6% (31/38) of cases in a test sample. Neither ascites nor immunoglobulins were useful for the estimation of the prognosis.

[Clinical and biological aspects of macroamylasemia (author's transl)]. / Aspects cliniques et biologiques de la macroamylasémie. A propos d'un cas.

The authors report a case of macroamylasemia in which the diagnosis was made with some difficulty. A hyperamylasemia was discovered after the patient, an alcoholic, had been hospitalized for atypical abdominal pain and weight loss, and this was thought to be due to an acute episode of chronic pancreatitis. The absence of an incrase in amylasuria suggested the presence of a macroamylasemia, and both diagnoses were confirmed by suitable exploratory investigations. Alcoholic cirrhosis was also present. The two main known types of macroamylase and their iatrogenic variant are described as well as the incidence of this biological anomaly in the general population. Confirming the presence of this anomaly in the plasma is a delicate and complex procedure. Simultaneous study of amylase-creatinine clearance ratio was thought to be a decisive test, but this does not appear to be true.

[In vitro and in vivo stability of macroamylase (author's transl)]. / Stabilité in vivo et in vitro de la macroamylase.

A complex case of macroamylasemia in an alcoholic subject with chronic pancreatitis is presented here. The existence of a macroamylase, suggested by hyperamylasemia associated with low amylasuria and by values of the ratio amylase clearance/creatinine clearance lower than 1%, was confirmed by the profile of the amylase activity after filtration on gel of the patient's serum. The macroamylase activity of samples taken at various times over a period of seven months presents a variable characteristic: lowered at the beginning of the fourth month, it rose suddenly following a portal systemic encephalopathy, then became nil a fortnight later. This oscillating character found during the following months is not associated with the values of the serum amylase. The subject's pancreatic juice had no macroamylasic activity but the pancreatic amylase, in vitro, may be feebly linked to a constituant of the patient's serum. The nature of the protein associated with the amylase was not discovered. To in vivo variations of the macroamylase activity may be added the notion of in vitro variability for a sample conserved at -18 degrees C.

[Critical study of methods of estimation by an enzymatic method of serum triglycerides (author's transl)]. / Etude critique de méthodes de dosage par voie enzymatique des triglycérides sériques.

The authors describe a critical study of two entirely enzymatic methods of determination of serum triglycerides which differ mainly by the choice of hydrolytic agents: esterase and hydrolase by the Roche methods, lipase and esterase in the case of the Boehringer method. The estimation of the resulting free glycerol requires 3 sequential enzymatic reactions (glycerol kinase, pyruvate kinase, lactate dehydrogenase, ending by the measurement of the consumed reduced NAD. The study of the kinetics of the analysis in two stages is carried out using standard solutions of glycerol and with human sera of variable concentration; the optimal conditions of the reaction time and temperature are drawn up. The trials of repeatability and reproducibility from day to day were carried out together with evaluation of the precision. The method was compared with Beohringer's method (n = 50) using hydrolysis of alcoholic potash. The authors conclude on the use of the methods studied.

[Automated method for determining calcium in biological liquids]. / Méthode de dosage automatique du calcium dans les liquides biologiques.

A method of determination of calcium in biological fluids is proposed. It is a continuous flow technic without deproteinisation nor dialysis, using orthocresol phtaleine in alkaline medium. The interference due to magnesium is eliminated by the presence of hydroxy-8-quinoleine. The addition of dimethyl sulfoxide improves the solubility of the reagents and ensures better stability of the media. The correlation between the results obtained by this technic and by atomic absorption spectrophotometry was studied on 160 human sera and 40 urines. The influence of various parameters such as hemolysis, bilirubin, magnesium and phosphates is low or negligeable. The results concerning opalescent, cloudy or lactescent sera may be erroneous by excess. The physiological reference values for serum calcium are drawn up from a Paris student population of both sexes.