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Biomedical subjects

C Colin

Publications and source records attributed to C Colin.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Copper binding studies of lipases from different sources using image binding: mechanism of free copper and chelated copper.

Immobilized metal-ion affinity gel electrophoresis (IMAGE) has been demonstrated to be an efficient tool to study the binding of proteins to chelated transition metals such as Cu(II). IMAGE was exploited to isolate several lipases from different sources and so evaluate their affinities for iminodiacetic acid (IDA)-Cu(II) and, in particular, to evaluate their enzymatic activities while retained on a gel (IMAGE) containing chelated copper [IDA-Cu(II)]. It was found that all lipases can be active within the gel while being coordinated to IDA-Cu(II). It is concluded that active site histidine (most likely) is not involved in the metal recognition and thus other resident histidines serve as electron donors. This is mainly attributed to the known phenomenon of occlusion of the catalytic site by more or less rigid lid structures. The involvement of active site histidine in hydrogen bonding is also evoked.

Animals↗
PubMedDate not supplied

Preliminary study of the metal binding site of an anti-DTPA-indium antibody by equilibrium binding immunoassays and immobilized metal ion affinity chromatography.

Creating metal coordination sites by modifying an existing enzyme or by eliciting antibodies against metal chelate haptens is of great interest in biotechnology to create enzyme catalysts with novel specificities. Here, we investigate the metal binding potential of a monoclonal antibody raised against a DTPA-In(III) hapten (mAb 734). We study its relative binding efficiency to metals of biological relevance by equilibrium binding immunoassays and immobilized metal ion affinity chromatography, two approaches which can give complementary information regarding composition and/or structure of the metal binding site(s). Fe(III), Fe(II), Cu(II), Mg(II), Ca(II), and Zn(II) binding was compared to In(III). All of them were shown to displace indium, but their affinity for mAb 734 decreased by 100-fold compared to indium. Competitive metal binding immunoassays between Zn(II) and In(III) revealed an unusual behavior by Zn(II) which remains to be explained. Moreover, IMAC allowed us to predict the metal binding amino acids involved in the antibody paratope. The antibody metal binding site was shown to contain at least two histidine residues in a cluster, and the presence of aspartic and glutamic acid as well as cysteine residues could not be excluded. Thus, simple competition studies allows us to obtain some partial information on the metal binding structural features of this anti-metal chelate antibody and to guide our screening of its catalytic potential.

Antibodies, Monoclonal↗
PubMedDate not supplied

Availability of calcium from skim milk, calcium sulfate and calcium carbonate for bone mineralization in pigs.

Dairy products provide abundant, accessible calcium for humans, while some calcium sulfate-rich mineral waters could provide appreciable amounts of calcium. But there is little evidence that this calcium is as available as milk calcium for making bone. The availability of calcium was studied by monitoring bone parameters in 2-month-old pigs fed restricted amounts of calcium (70% RDA) for 2.5 months. The 3 main (> or = 50% Ca intake) Ca sources were either CaCO3 or CaSO4 or skim milk powder (29% of the diet). The bones of the pigs fed the "milk" diet had higher (P < 0.01) ash contents, breaking strength and density (DEXA) than those of the two others groups, in which the bone values were similar. Thus, the calcium provided by a diet containing milk appears to ensure better bone mineralization than do calcium salts included in a non-milk diet. The calcium restriction may have enhanced some milk properties to stimulate calcium absorption in these young, rapidly growing pigs.

Alkaline Phosphatase↗
PubMedDate not supplied

[Results of a policy of conservative treatment of breast cancer (146 cases)].

Tumorectomy and irradiation for small cancer of the breast. Tumorectomy followed by breast irradiation and a single course of chemotherapy is the most accurate treatment for small cancer of the breast. The 5 and 10 years survival are 92.5% and 85% respectively: this demonstrates the efficacy of the conservative treatment in the control of most of the small breast cancer provided a strict selection of the cases was done. Patients who develop local recurrence have the same life expectancy than the other cases when they are soon treated by mastectomy.

Breast Neoplasms↗
PubMedDate not supplied

[Premenstrual mastodynia: objective signs (author's transl)].

Mammary congestion is mainly a painful syndrome, principally related to diffuse edema of the gland, the radiological signs of which are described in this report. Excellent validity can be obtained by a trained observer of these signs. In contrast, however, thermographic signs are of less value, probably due to the presence of a more or less abundant superficial edema. This interferes with thermal propagation towards the skin covering, and could be the cause of the superficial hypothermia which is recorded in one third of patients with definite clinical congestion. Hormonal disturbances are observed frequently enough in this syndrome for them to be considered responsible for a large proportion of the congestive and edemaotus phenomena. Observation of these signs enables a choice of therapy to be made, but this is not discussed in this report.

Adult↗
PubMedDate not supplied

[Ultrasonography investigation of mammary calcifications (author's transl)].

Ultrasonography recordings in 140 patients with breast cancer, 119 with cystic mastopathy, and 299 with benign mammary tumours showed that calcifications are rarely demonstrated, and that diagnosis is not affected to any degree when they are present. Ultrasonography should be used for examination of the breast following the three traditional clinical, radiological, and cytological investigations. False negatives (7.9% of cancers) and false positives (4.2% of fibro-adenomas) are easily corrected from radiological and cytological findings which are still essential for the diagnosis of most mammary affections. Ultrasonography, however, enables an appreciable reduction in biopsy requests to be made in less than 6% of cases of atypical microcalcification in benign mammary lesions.

Breast Diseases↗
PubMedDate not supplied

[Lactation].

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Breast↗