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Biomedical subjects

I Maire

Publications and source records attributed to I Maire.

At least 19 recordsLinked to original sources
PubMed1995

Processing of iduronate 2-sulphatase in human fibroblasts.

Iduronate 2-sulphatase (IDS) is a lysosomal enzyme involved in degradation of dermatan sulphate and heparan sulphate. Antigenic material was obtained either by purification of placental IDS (A and B forms) or by expression of three different fusion peptides in Escherichia coli allowing the production of five specific antibodies. Pulse-chase-labelling experiments in over-expressing fibroblasts showed poor IDS processing but large amounts of precursors were secreted into the medium. The endocytosis of the 35S- or 33P-labelled precursors by deleted fibroblasts together with glycosylation studies and proteolysis inhibition by leupeptin allowed better elucidation of IDS maturation. The initial 73-78 kDa form is converted into a phosphorylated 90 kDa precursor after modification of its oligosaccharide chains in the Golgi apparatus. This precursor is processed by proteolytic cleavage through various intermediates to a major 55 kDa intermediate, with the release of an 18 kDa polypeptide. Further proteolytic cleavage by a thiol protease gives the 45 kDa mature form containing hybrid and complex-type oligosaccharide chains.

Base Sequence↗
PubMed1995

An abnormal exercise test response revealing a respiratory chain complex III deficiency.

A 29-year-old man with a progressive exertional muscle intolerance since childhood was referred for incremental exercise test on a bicycle ergometer. The response pattern suggested a mitochondrial myopathy: that is, a greatly reduced maximum oxygen consumption with appropriate heart rate increase and an anaerobic threshold point reached early. The metabolic investigation in plasma revealed an abnormal oxidoreduction status (hyperlactataemia and high lactate/pyruvate ratio) at rest and after a carbohydrate rich meal. The histochemical examination of a muscle biopsy revealed red granular deposits under the sarcolemma for all type 1 fibers. Oxypolarographic and enzymological studies of the mitochondrial respiratory chain in both isolated mitochondria and muscle homogenate demonstrated a marked deficiency of ubiquinol cytochrome c reductase (complex III) activity.

Adult↗
PubMed1995

[Improvement of result coherence in clinical enzymology: multicenter study of gamma-glutamyltransferase, alkaline phosphatase and amylase activities].

We report here on the results of a multicenter study of three enzyme activities (gamma-glutamyltransferase, alkaline phosphatase and amylase). For each activity, measurements were performed in two laboratories on different series of patients' specimens under routine conditions, at 30 and 37 degrees C, with techniques frequently used in France and with the IFCC reference method, when it exists. For each technique, precision was acceptable, but results differed considerably according to the technique used. The study also showed that for different techniques it is not possible to use a single transformation factor for activities between 30 and 37 degrees C. Patients' results determined by two techniques often showed a constant relationship. Groups of techniques that determined the same catalytic activity in patients' specimens were identified, whereas other techniques did not have this property. Several preparations, including reference materials produced by the Community Bureau of Reference (European Community, Brussels) and ten commercial secondary materials were tested for similar behaviour as compared to patients' samples. Results show the commutability of reference materials within a group of techniques indicating that they can be used as calibrators. This was seldom the case for the commercial secondary materials and we did not find any such material suitable for calibration of the three enzymatic activities. The present study demonstrates that with defined techniques and validated calibrators it is possible to reduce considerably differences between results obtained with different techniques at different temperatures and in different laboratories.

Alkaline Phosphatase↗
PubMed1994

[Severe cardiomyopathy revealing amylopectinosis. Two cases in adolescents from the same family].

Type IV glycogen storage disease, also termed Andersen's disease or amylopectinosis, is a rare autosomic recessive hereditary disease usually caused by a deficit in glycogen branching enzyme. We report our observation of two siblings with type IV glycogen storage disease who had normal branching enzyme activity. The initial symptom was severe heart failure. A 14-year-old boy, born to consanguinous parents, was seen for severe global heart failure. Growth retardation had been diagnosed since the age of 6 and abnormal fatigability since the age of 12. Muscle and endomyocardium biopsies revealed abnormal glycogen storage with normal branching enzyme activity. The patient's condition improved after symptomatic treatment, but death occurred due to infectious complications after orthoptic heart transplantation. One year later, the proband's 12-year-old sister, with an uneventful personal medical history, was hospitalized for severe left ventricular failure. Muscle and liver biopsies demonstrated the same anomalies, again without branching enzyme deficiency in the liver. Heart failure was controlled with symptomatic care and the patient's current condition remains satisfactory. This observation demonstrates the clinical expression of familial type IV glycogen storage disease in patients with normal branching enzyme activity. Age at onset is quite variable, reported from 5 to 70 years, as is the clinical course before diagnosis.

Adolescent↗
PubMed1994

Reference materials in clinical enzymology: preparation, requirements and practical interests.

Five enzyme materials (gamma-glutamyltransferase, alkaline phosphatase, creatine kinase, alanine aminotransferase and prostatic acid phosphatase) are currently certified using a reference method. Furthermore, feasibility studies have been performed for four other enzymes (aspartate aminotransferase, lactate dehydrogenase, amylase and lipase). They indicated that these enzymes can be purified and stabilized, but the materials have not yet been certified. This shows that the most important enzymes in clinical laboratories can be purified, and stabilized, without significant alteration of their catalytic properties. By carefully choosing a matrix, the commutability of these enzyme preparations and patients' samples between some methods, including routine methods, may be preserved. Thus, these materials can be used to calibrate the routine methods in terms of the corresponding reference methods after commutability has been verified. Current studies suggest that this objective can be reached, provided three criteria are satisfied: i) the calibrated and reference methods must be of equal specificity; ii) the enzyme calibrator should be, as closely as possible, identical to the human analyte enzyme in its native matrix (eg serum); iii) and the inter-method ratio should be constant (within the limits of experimental error) for the enzyme calibrator and for all patients' samples.

Calibration↗
PubMed1993

Diagnosis of mucopolysaccharidoses in a clinically selected population by urinary glycosaminoglycan analysis: a study of 2,000 urine samples.

Two thousand urine samples (from patients presenting with clinical features suggestive of a mucopolysaccharidosis, MPS) were analysed by a procedure that included a quantitative measurement of glycosaminoglycan (GAG) hexuronic acids (harmine reagent), a qualitative GAG analysis (cellulose acetate electrophoresis) and a study of urinary oligosaccharide patterns. One hundred and seventy MPS and 29 oligosaccharidosis-affected patients were found, but 23 MPS patients among the 170 would have been missed by use of a quantitative procedure only. Fourteen of these (mainly MPS IV A) were detected on the basis of abnormal electrophoresis and the 9 others on the basis of abnormal urinary oligosaccharide patterns (MPS IV B patients). Our results emphasize that normal quantitative GAG excretion alone cannot rule out a diagnosis of MPS; qualitative analysis is also required, as well as oligosaccharide screening.

Adolescent↗
PubMed1993

Acid and neutral lipase activity in lymphocytes of patients with increased serum cholesterol and triglyceride level.

Acid lipase activity (ALA) and neutral lipase activity (NLA) in lymphocytes of patients with primary hyperlipidemia (hypercholesterolemia or/and hypertriglyceridemia) were compared with that of an age-matched control group (blood donors). The specificity of lipase was confirmed by the use of cardiolipin the well known activator of acidic lipase. beta-D-glucuronidase activity was used as a marker of the lysosomal release reaction. ALA (by 33%) and beta-D-glucuronidase (by 55%) activity, but not NLA in lymphocytes of the group of hyperlipidemic patients, was significantly lower when compared to the control group. A negative correlation between the serum cholesterol level and ALA, NLA and beta-D-glucuronidase release from lymphocytes of hyperlipidemic subjects was observed. The serum HDL cholesterol level was positively correlated with ALA within this group. These results suggest that the high cholesterol level in serum can unspecifically supress ALA and (to the smaller degree) NLA activity in lymphocytes of hyperlipidemic subjects. The decrease of lipase activity may promote deposition of lipids in cells and the development of atherosclerosis. The parallel decrease of beta-D-glucuronidase activity in lymphocytes of hypercholesterolemic patients suggests the impairment of immune system in hypercholesterolemia.

Adult↗
PubMed1993

[Value of skin fibroblasts in culture for the diagnosis of mitochondrial cell dysfunction. Apropos of 5 cases with cytochrome c oxidase deficiency].

Mitochondrial respiratory chain dysfunction has been studied by two complementary methods using cultured skin fibroblasts from five patients with muscular cytochrome c oxidase (complex IV) deficiency: first, a screening test measuring lactate to pyruvate ratio (L/P) after supplementation of cultured cells; secondly, measurement of complex IV activity in whole cells. Respiratory chain defect (increased L/P ratio with decreased complex IV activity) was expressed in fibroblasts of four of the five patients. Our results show that skin fibroblasts can be helpful for biochemical diagnosis of mitochondrial respiratory chain defects.

Cells, Cultured↗
PubMed1991

The place of fetal liver transplantation in the treatment of inborn errors of metabolism.

Over the last 16 years, 202 fetal tissue transplants have been performed in our department to treat 29 patients with severe inborn errors of metabolism without immunodeficiency, 26 patients with congenital and severe immunodeficiency diseases, and 2 patients with severe aplastic anaemia. The actuarial survival curve of patients with inborn errors of metabolism treated with fetal liver transplantation shows a 12-year survival of 77%. The condition of many of these patients has been improved by the treatment, but transplantation has had to be repeated in order to maintain clinical amelioration. Enzyme levels were not significantly and durably increased in peripheral blood but the quantities of substrates detected in sera and urines were significantly reduced and tissue deposits were stabilized.

Adolescent↗
PubMed1991

Biochemical diagnosis of hepatic glycogen storage diseases: 20 years French experience.

French experience of 242 cases of liver glycogenoses is reported. Screening tests based on serum biochemical data and glucagon tolerance tests are briefly reviewed. The diagnosis of types I glycogen storage disease (GSD) was ascertained in 73 patients' liver biopsies by measurement of glycogen content and by studying the glucose-6-phosphatase system. Liver biopsies were also required at the beginning for the diagnosis of other hepatic GSDs; later on, the possibilities of diagnosis using peripheral blood cells were investigated. Eighty-four cases of type III GSD were confirmed by measurement of debranching enzyme activity and glycogen content using either liver biopsies (78 cases) and/or erythrocytes (37 cases); enzyme determination was also performed in leukocytes and/or fibroblasts for 18 patients. Twenty-four cases of type VI GSD underwent liver biopsies, and the diagnosis could be confirmed using mononuclear or polymorphonuclear cells for 11 of these patients. Sixty-one patients were identified as type IX GSD; phosphorylase kinase deficiency was demonstrated in erythrocytes for all patients, and a liver biopsy was analyzed for 26 of these cases. From this experience, the possibilities of diagnosis of liver GSD using peripheral blood cells are emphasized.

Blood Chemical Analysis↗
PubMed1991

[Mannosidosis type II].

Four out of 7 siblings born of non-consanguineous parents have presented psychomotor retardation, macrocephaly and facial dysmorphism associated in 2 of them with thoraco-lumbar kyphosis and in one of them with recurrent pulmonary infections which had resulted in death. Chromatography of oligosaccharides displayed a characteristic mannosidosis profile. In addition, D-mannosidase activity was very low in leucocytes and fibroblasts. The father and mother showed no clinical abnormality and had no pathological urinary oligosaccharide excretion, but their leucocyte and fibroblast D-mannosidase activity was reduced. These cases give the authors an opportunity to describe the clinical and biochemical features of mannosidosis, which in its type II enables the patients to survive into adulthood, and to underline the value of D-mannosidase assays to detect subjects with this anomaly.

Adult↗
PubMed1990

Myopathic evolution of an exertional muscle pain syndrome with phosphorylase b kinase deficiency.

The symptoms of a myopathy permanently affecting limb girdle muscles are reported in a 31-year-old woman who has been presenting an exertional muscle pain syndrome with myoglobinuria for 20 years. Investigations revealed a slightly decreased utilization of glycogen in muscle, while its storage affected only rare type 2 fibers. Active phosphorylase was undetectable and phosphorylase b kinase activity was clearly decreased in muscle cells, but normal in erythocytes, lymphocytes and cultured fibroblasts.

Adult↗