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Biomedical subjects

P Merle

Publications and source records attributed to P Merle.

At least 55 records · Page 3Linked to original sources
PubMed1982

Kinetic and structural differences between cytochrome c oxidases from beef liver and heart.

1. The cytochrome content of beef liver mitochondria differs from that of beef heart mitochondria by an eightfold lower cytochrome aa3 and a twofold lower cytochrome b and c + c1 content. 2. The kinetic properties of cytochrome c oxidases from beef liver and heart were measured with intact cytochrome c-depleted membranes, deoxycholate-dissolved membranes, and with the isolated enzymes at various cytochrome c concentrations with an oxygen electrode. Under all conditions a higher V was found for the liver enzyme, both for the low-affinity and for the high-affinity binding site for cytochrome c. Differences were also found for the Km of the two enzymes. 3. Isolated beef heart mitochondria contained about twice as much cardiolipin than beef liver mitochondria. The isolated enzymes contained one mole cardiolipin per mole of the heart enzyme, but 2 moles cardiolipin per mole of the liver enzyme. 4. By application of a high performance sodium dodecylsulfate gel electrophoretic system the two isolated enzymes could be separated into 13 different protein components, three of which (polypeptides VIa, VIIa and VIII) were found to differ in their apparent molecular weights. The functional meaning of cytochrome c oxidase isoenzymes in liver and heart is discussed.

Animals↗
PubMed1981

Immunological and chemical characterization of rat liver cytochrome c oxidase.

Rat liver cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase; EC 1.9.3.1) was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into 12 different polypeptide chains. Specific antisera against the holoenzyme and against purified subunits IV and VIII were used to characterize the enzyme complex. The antiserum against subunit IV precipitates from sodium dodecyl sulfate-dissociated mitochondria only subunit IV and from Triton X-100-dissolved mitochondria all 12 polypeptide chains, indicating their integral location within the enzyme complex. Different antisera against the holoenzyme only precipitate subunits IV, V and VIb from sodium dodecyl sulfate-dissociated mitochondria, suggesting the location of these subunits on the surface layer of the complex. Subunit VIII is thought to be located within the complex, since a specific antiserum does not precipitate the complex. The amino acid composition of all 12 protein subunits is different, thus excluding their origin from proteolytic degradation. The proteolytic degradation of subunit IV into IV during isolation of the enzyme was corroborated by the very similar amino acid composition of both proteins.

Amino Acids↗
PubMed1980

The subunit composition of mammalian cytochrome c oxidase.

Cytochrome c oxidase from rat liver mitochondria was separated into 12 different protein subunits by application of a highly resolving sodium dodecylsulfate/gel electrophoretic system of different compositions. The 12 protein subunits are shown to represent integral components of mammalian type cytochrome c oxidase for the following reasons. 1. All 12 subunits copurify through various purification procedures. 2. The subunit composition of the isolated enzyme is identical to that of the immunoprecipitated one. 3. All 12 subunits are present in the complex at one to one stoichiometric amounts. 4. A similar composition of 12 subunits was also found for cytochrome c oxidase from rat kidney, pig heart, rabbit liver and stone-marten liver. The difference between our results and all other published data on the subunit composition of mammalian-type cytochrome c oxidase, based on gel electrophoretic analysis, is due to the insufficient resolving power of previously used gel systems and the very similar molecular weight of subunits VIa, b, c, and VIIa, b, c.

Animals↗
PubMed1980

[Radiological appearances of osteochondritis of the hip in children].

Radiological examinations are of primary importance in the diagnosis of osteochondritis of the hip in the children, and enable appropriate therapy to be selected. The classification described by Catterall is preferred to that of Taillard, which describes the classical stages of the disease, as it has prognostic value when frontal and profile hip x-rays are taken.

Age Factors↗
PubMed1979

Primary empty sella turcica in children. Report of two familial cases.

The authors describe cranio-facial deformities found in two sisters and associated with spinal anomalies, short stature and delayed skeletal maturation. The principal radiological features were an enlarged J-shaped sella turcica and intrasellar cisternal herniation. Enlargement of optic foramina and internal acoustic canals were also present. These asymptomatic cases of "empty sella" seem to be part of a general dysplastic syndrome rather than a local disease.

Adolescent↗
PubMed1975

[Pseudohypohyperparathyroidism or Frame's pseudohypoparathyroidism type I].

Case report of a girl with fibrous osteitis lesions associated with clinical and biological symptoms of pseudo-hypoparathyroidism: hypocalcemia, hyperphosphoremia, absence of increase of phosphaturia (urine phosphate level) and especially of cyclic AMP after parathormone injection, high serum parathormone level. Similar cases described in literature are shortly analyzed. The genetic, pathogenic and nosologic problems of such an association are reviewed.

Calcium↗