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Biomedical subjects

M Mathieu

Publications and source records attributed to M Mathieu.

At least 181 records · Page 10Linked to original sources
PubMed1989

[Lysosomal enzyme deficiency: in vitro correlation of deficient cells using a conditioned medium or by co-culturing with non-deficient cells].

We demonstrate that lysosomal enzyme (alpha-L-fucosidase) can enrich deficient fibroblasts, with purified enzyme brought by the medium, or with an enzyme supply by various cell sources. The co-culture systems lead to a deficient cell correction, whatever donor cells are lymphocytes or lymphoblastoid cells. This correction arise only with alive cells, and is strongly inhibited by mannose-6-phosphate. Our results do not support the hypothesis that cell to cell contact independently of mannose-6-phosphate binding site is necessary for transfer of lysosomal enzyme from lymphocytes to fibroblasts. We suggest that the neighbourhood of cells leads to a phosphorylated precursor increase in the pericellular area, which creates an enzyme stabilizing effect favourable at its incorporation.

Cell Communication↗
PubMed1989

[Marfan disease presenting in neonates with rapid cardio-vascular failure. Apropos of 2 cases].

We report two exceedingly unusual and severe cases of Marfan syndrome with neonatal manifestations. Clinical features were caricatural. The skin was of the cutis laxa type. Both infants died shortly after birth as a result of severe cardiovascular lesions. Histologic examination of the aortic media confirmed the diagnosis. Because this genetic connective tissue dysplasia is inherited on an autosomal dominant basis with strong penetrance, and because in both instances the two parents had a negative family history, a dominant mutation seems likely in our cases and prompted us to be optimistic when giving genetic counseling. We point out the characteristic features of these exceptional early forms and describe the results of a detailed histologic examination of the skin that completes data from the literature.

Aorta↗
PubMed1989

Homogentisic acid determined in biological fluids by HPLC.

In this rapid, specific, and sensitive high-performance liquid-chromatographic method of analysis for homogentisic acid in biological fluids, homogentisic acid is separated on a column of Nucleosil CN. This method, which we applied to the diagnosis of three cases of alcaptonuria, represents a suitable analytical tool for the diagnosis of alcaptonuria.

Adult↗
PubMed1988

The ethanol regulon in Aspergillus nidulans: characterization and sequence of the positive regulatory gene alcR.

The regulatory gene, alcR, of Aspergillus nidulans, encodes a protein that induces the expression of the alcA and aldA genes. The alcR gene is inducible, autoregulated, and subject to carbon catabolite repression. We report the complete nucleotide sequence of the alcR gene and its 5' and 3' non-coding regions. In the 5' flanking region of the alcR gene, several repeats and inverted repeats were found, and small sequence similarities were also found with the 5' flanking regions of the alcA and aldA genes. One intron of small size interrupts the open reading frame. The start point of transcription was mapped 50 nucleotides upstream from the putative start codon, and a sequence CAATG was found 5' to the polyadenylation site of the transcript that could play a role in selection of the polyadenylation site. The putative alcR-encoded protein was identified in vivo as an inducible polypeptide of 96 kDa in a transformant carrying multiple copies of the alcR gene.

Alcohol Dehydrogenase↗
PubMed1988

Interleukin 1 enhances growth factor-dependent proliferation of the clonogenic cells in acute myeloblastic leukemia and of normal human primitive hemopoietic precursors.

IL-1 is released by activated monocytes and is thought to be a key mediator of the host immune response. The availability of the purified and, more recently, recombinant IL-1 has allowed the characterization of other biological properties of this molecule. Thus, IL-1 is thought to have the same properties as hemopoietic 1, a growth factor that has been shown to act on primitive murine hemopoietic cells. Here we report that rIL-1 acts synergistically with granulocyte/macrophage CSF (GM-CSF) or granulocyte CSF in the stimulation of clonogenic cells from many patients with acute myeloblastic leukemia (AML). Although IL-1 by itself has no effect on AML blasts, it can support colony formation under conditions where there is detectable production of endogenous GM-CSF. IL-1 also promotes the growth of multipotential progenitors from normal human bone marrow cells in the presence of GM-CSF. These observations support the hypothesis that in the hemopoietic system, IL-1 has a selective effect on primitive precursors.

Bone Marrow Cells↗
PubMed1988

A gonial mitosis-stimulating factor in cerebral ganglia and hemolymph of the marine mussel Mytilus edulis L.

A gonial mitosis-stimulating factor produced by the cerebral ganglia of the mussel Mytilus edulis has been demonstrated. This factor induces an increase of [3H]thymidine incorporation in the DNA of isolated mantle cells. Dose-response data are obtained with the methanol phase of an acidic ganglia extract. The rate of [3H]thymidine incorporation is compared with aspartate transcarbamylase specific activity, another bioassay previously described to estimate mitotic activity. This heat-stable mitogenic factor appears to have a molecular weight of less than 5000 Da. A gonial mitogenic factor is also found in the hemolymph and circulatory cells.

Animals↗
PubMed1988

What does inductance plethysmography really measure?

Inasmuch as it has been claimed that inductance plethysmography can measure cross-sectional area changes, we tested this assumption. We present experimental and computed relationships between self-inductance (L) of coils and areas (A) included inside for a coil with a well-defined side wavy pattern (triangular or sinusoidal) and for a real belt (Respitrace) placed on elliptical or rectangular configurations. The results are applied to the physiological field using measurements obtained from a computed tomography experiment. We demonstrate that the L-A relationships vary not only with shape or ellipticity of the cross section but also with the wavy pattern shape. This last parameter is critical because it is difficult to actually control. When the coil wavy pattern remains steady, there are some physiological situations where inductance plethysmography can more accurately estimate area changes: when the configuration shape is constant, the correspondence between delta L and delta A is almost linear with a shape-dependent sensitivity; when the configuration is nearly circular (ellipticity in the range 0.8-1), the relative error in delta A estimation is less than 5%.

Humans↗
PubMed1988

[Biological diagnosis of hereditary metabolic diseases. From selective screening to the mutant-cell bank].

The experience of a specialized laboratory for the biological diagnosis of inborn errors of metabolism in selected pediatrics patients is reported. The strategy starts with a wide testing of blood and urine, as many inborn errors of metabolism can be detected through testing of blood and urine for increased concentration of specific metabolites known to be associated with the genetic defect. Then enzymatic or DNA studies are performed to confirm the diagnosis. The mutant cells mostly fibroblasts are stored in a cell bank and available for other research.

Cells, Cultured↗
PubMed1987

The inborn errors of mitochondrial fatty acid oxidation.

To date, seven inborn errors of mitochondrial fatty acid oxidation have been identified. A total of about 100 patients in the world have been reported. Clinically the beta-oxidation defects are more often characterized by episodic hypoglycaemia leading to a coma mimicking Reye's syndrome. The hypoglycaemia is non-ketotic since the synthesis of ketone bodies is deficient. Periods of decompensation occur when carbohydrate supply is poor, e.g. prolonged fasting, vomiting, or increased caloric requirements, as and when lipid stores are used. Defects in beta-oxidation have also been reported to be one cause of sudden infant death syndrome. The diagnosis of these inborn errors is by biochemical investigation since where symptoms suggest such a defect, the precise aetiology cannot be assessed. The biochemical diagnosis is based firstly on identification of abnormal plasma and of urinary metabolites during acute attacks. Derivatives of the omega-oxidation and omega-1-oxidation of medium chain fatty acids have been identified, as well as acylglycine and acylcarnitine conjugates. These metabolites are nearly always absent when patients are in good clinical condition. Secondly, the diagnosis must be based on the identification of the enzymatic defects: this involves global assays which allow a localization of the 'level' of the defect (i.e. the oxidation of long, medium or short chain fatty acids) and specific measurement of enzyme activities (acyl-CoA dehydrogenases and electron carriers: ETF and ETF-DH). The diagnosis of these disorders is of prime importance because of the severity of the clinical symptoms. These can be prevented, in some cases, by an appropriate diet (a high carbohydrate, low fat diet, sometimes supplemented with L-carnitine). In other cases, genetic counselling can be offered.

Carnitine↗
PubMed1987

Use of a synthetic peptide antigen to generate antisera reactive with a proteolytic processing site in native human proinsulin: demonstration of cleavage within clathrin-coated (pro)secretory vesicles.

Polyclonal antibodies reactive with a cleavage site in human proinsulin (HPI) (C-peptide-A-chain junction) have been raised (rabbit, guinea pig) using a synthetic peptide antigen coupled with keyhole limpet hemocyanin. These antisera recognize native HPI and des-31,32-HPI equally well but react 20-50 times less well with des-64,65-HPI, the intermediate cleaved at the C-peptide-A-chain junction and lacking the Lys-Arg pair. The guinea pig antisera did not recognize insulin but reacted weakly with C peptide at high concentrations; the rabbit antisera reacted with neither insulin nor C peptide. Immunocytochemical studies with human islet tissue localized the immunoreactivity of these antisera to clathrin-coated (pro)secretory vesicles derived from the trans Golgi, indicating that cleavage of the C-peptide-A-chain junction of proinsulin occurs mainly, if not exclusively, in this compartment of the beta cell.

Antibodies↗
PubMed1987

Regulation of alcR, the positive regulatory gene of the ethanol utilization regulon of Aspergillus nidulans.

The alcR positive control gene is necessary for the expression of both alcA (coding for alcohol dehydrogenase ADH I), and aldA (coding for aldehyde dehydrogenase, AldDH) in Aspergillus nidulans. Using a cloned alcR probe and Northern blots analysis we show that: (1) alcR itself is inducible; (2) alcR inducibility depends on the expression of the alcR gene itself; and (3) alcR is subject to carbon catabolite repression and its expression is controlled by the negatively acting creA wide specificity gene. The repression of alcR is sufficient to explain the carbon catabolite repression of ADH I and AldDH.

Alcohol Dehydrogenase↗
PubMed1987

Recurrence of pulmonary embolism during anticoagulant treatment: a prospective study.

The risk of early recurrence of pulmonary embolism in patients with venous thromboembolic disease treated by anticoagulants is not well established. To determine the risk linked to contemporary proximal deep venous thrombosis, a prospective study was organised to give clinical and scintigraphic surveillance to 50 patients with angiographically proved pulmonary embolism plus phlebographically proved proximal deep vein thrombosis during the first 15 days of anticoagulant treatment. Perfusion lung scans were performed initially and on days 3, 7, and 15. Only two patients had a recurrence of pulmonary embolism during this period; both episodes were revealed by new symptoms, and one recurrence was fatal. The systematic performance of angiography in four patients found to have new scintigraphic defects led to the diagnosis of "spurious scintigraphic recurrence" in three of them. It is concluded that (a) adjusted anticoagulant treatment showed an effectiveness of 96% for preventing early recurrence of pulmonary embolism in this group of supposed high risk patients, and (b) in patients with recent pulmonary embolism new defects on systematic perfusion lung scans are not specific indicators of recurrent pulmonary embolism.

Adult↗
PubMed1987

[Accidents caused by arteritis after fracture or tibial osteotomy].

In five cases of fracture or osteotomy of the tibia complicated by delayed union, non-union or infection, a latent chronic vascular insufficiency was belatedly discovered, often after failure of local treatment. It was responsible for the complication, since, in all the cases, the restoration of arterial patency resulted in healing. A study of the arterial circulation should be made, especially in smokers, when there is delay in union.

Aged↗
PubMed1986

Possible prenatal diagnosis of type III glycogenosis.

This paper reports the first prenatal diagnosis in a pregnancy at risk for type III glycogenosis using a reliable test for amylo-1,6-glucosidase in cultured amniotic fluid cells. This test, based upon the different rates of glycogen and phosphorylase limit dextrin hydrolysis, was found to be more reliable in detecting a deficiency of amylo-1,6-glucosidase activity than either phosphorylase limit dextrin hydrolysis alone or [14C]glucose incorporation using leukocytes and cultured cells.

Amniotic Fluid↗
PubMed1986

A comparison of celiprolol and chlorthalidone in hypertensive patients with reversible bronchial obstruction.

The objective of this study was to evaluate the effects of celiprolol, a new beta-blocking drug, on the clinical condition and pulmonary function of hypertensive patients with reversible bronchial obstruction. Celiprolol was compared with chlorthalidone, an antihypertensive drug without known effect on bronchial tone. The study consisted of a 4-week placebo run-in period and a 12-week titration period in which the dose of both drugs was increased at 4-week intervals if blood pressure was not reduced adequately. The doses of celiprolol were 200, 400, or 600 mg once daily; those for chlorthalidone 12.5, 25, or 37.5 mg once daily. Entry criteria were a diastolic blood pressure between 90 and 115 mg Hg, and FEV-1 between 40% and 80% of predicted value, increasing by 15% or more after salbutamol, and a need for occasional bronchodilator therapy. Prophylactic medication for asthma was given in constant dosage for a month before the study and throughout the study. Preliminary results on 66 patients demonstrate that neither drug had a clinically significant effect on FEV-1, FEF 25-75, or FVC. Clinical variables were not significantly changed by either drug: the average monthly asthma attacks fell from 18 to 13 with celiprolol and from 11 to 7 with chlorthalidone. FEF was reduced by more than 50% in two patients on celiprolol and three on chlorthalidone. Monthly asthma attacks increased by more than 100% in five patients on celiprolol and four on chlorthalidone. Thus, preliminary results are unable to demonstrate adverse effects from celiprolol in patients with asthma and hypertension.

Adrenergic beta-Antagonists↗