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Biomedical subjects

C Mathieu

Publications and source records attributed to C Mathieu.

At least 181 records · Page 10Linked to original sources

[TRH test on 6 patients 47, XYZ (author's transl)].

A T.R.H. test has been made on 6 patients 47,XYY, living in a psychiatric hospital. The results show a thyroid disease with latent hypothyroidism whose origin seems to be hypothalamic, or pituitary or both.

Adult↗

[Biological effects of solutions of non-histone chromatin-associated proteins on cell differentiation in vitro (author's transl)].

Nuclear non-histone (NNH) proteins, both chromatin-associated and otherwise, have been prepared in defined conditions, either from nuclei or from washed chromatin. When these NNH proteins are homospecific, they produce inhibitory effects on morphological differentiation of embryonic Urodelan Amphibian cells cultivated in vitro. When they are heterospecific, on the contrary, they have no action on the differentiation of those cells. It is concluded that the effects of the non-histone proteins on cell differentiation depend upon the relationship between the animal species which is used to provide the proteins and that used to provide the reactive material.

Ambystoma↗

Assessment and visualization of the curvature of the left ventricle from 3D medical images.

We address the problem of using curvature features to assess the three-dimensional (3D) motion of the left ventricle. The adequacy of this approach depends on the actual characteristics of the curvature of the left ventricle and particularly on the spatial and temporal stability of these features. From experimental data, we compute the distribution of the Gaussian curvature over the surface of the left ventricle by using an iterative procedure. The results are visualized in 3D through a voxel-based surface rendering technique. We show that the Gaussian curvature remains stable along the cardiac cycle. This curvature feature could thus provide a reliable basis for further 3D motion analysis of the left ventricle.

Algorithms↗

Role of CD4+ and CD8+ T cells in the rejection of heart or islet xenografts in recipients with xenotolerance in the innate immune compartment.

UNLABELLED: To further study the interactions between innate and adaptive immunity in xenotransplantation, we explored the relative contribution of T-cell subsets in vascularized (heart) and cellular (islets) xenografts in a model with established xeno-non-reactivity of the innate system. MATERIALS: Specific innate xenotolerance was induced in xenoheart (hamster) recipients (nude rats) by a tolerizing regimen (TR), consisting of donor antigen infusion, temporary natural killer (NK)-cell depletion and a 4-week administration of leflunomide. Hamster pancreatic islets were transplanted either 1 week after heart transplantation or alone and syngeneic T-cell adoptive transfer was performed 10 days later. Purified CD3(+), CD4(+), and CD8(+) T cells were given 2 weeks after withdrawal of all drugs. At the day of rejection, xenografts were removed for histology. Serum was taken and IgM and IgG xenoantibody titers were measured by flow cytometry. RESULTS: Both heart and islet grafts were rejected after CD4(+) reconstitution. After CD8(+) T-cell adoptive transfer, cellular grafts were not rejected but vascularized grafts were rejected, although only after several months. Rejection in CD4(+) reconstituted nude rats was accompanied by the generation of predominantly IgG xenoantibodies. CONCLUSION: CD4(+) T lymphocytes are able to rapidly initiate the rejection of islet xenografts in the presence of a xenotolerant innate immune system either by breaking the "innate tolerance" (e.g., by activating macrophages and NK-cells) or through a mechanism without any involvement of the innate tolerance (e.g., T-dependent IgG antibody production). In contrast, CD8(+) T cells provoke a late rejection of only xenoheart grafts.

Animals↗

Effect of spermatozoa selection on a simplified Percoll gradient in case of asthenozoospermia.

Two methods for preparing semen (Swim-up migration and centrifugation on a two step density Percoll gradient) were tested in 21 cases of asthenozoospermia (motility less than 30%). The parameters of sperm movement were studied through automated videomicrographic analysis. In 9 cases out of 21 swim-up migration failed while centrifugation on a Percoll gradient failed in only 1 case out of 21.

Cell Separation↗

Nonclassical effects of 1alpha,25-dihydroxyvitamin D(3) and its analogs.

The activated form of vitamin D(3), 1alpha,25(OH)(2)D(3), not only plays a central role in bone and calcium metabolism but has also potent antiproliferative and prodifferentiating effects. Moreover, the combined presence of 25(OH)D(3)-1alpha-hydroxylase as well as the vitamin D receptor in several tissues introduced the idea of a paracrine role for 1alpha,25(OH)(2)D(3). By introducing chemical modifications into the flexible parent molecule 1alpha,25(OH)(2)D(3), a whole generation of vitamin D analogs was created. Due to a clear dissociation of the antiproliferative and prodifferentiating effects from calcemic effects, these analogs can be used not only for the treatment of bone disorders but also for non-classical applications.

Bone and Bones↗

Diabetic management in high risk patients (pregnancy, insulin pumps).

During the past decades our understanding about the clinical impact of diabetes has changed. We now know for certain that a good (read : near normal) glycemic control is necessary to prevent chronic complications of this disease in women regardless of the type of diabetes. Pregnancy is a specific situation whereby a "near normal" control is wanted not only for the patient but also for the fetus. Several studies have shown a correlation beween glycemic control and complications of pregnancy. Reaching optimal glycemic control is mandatory even before the pregnancy starts, considering the time window of occurance of the severe foetal congenital malformations (first weeks of pregnancy). The role of pre-conception care is emphasized. Optimal control in type 1 and type 2 diabetic patients can best be reached through intensive insulin therapy, but reaching normoglycemia is mainly limited by the occurence of hypoglycemia. The introduction of the new insulin analogues is an important step in our arsenal to achieve control using multiple daily insulin injections, but Novorapid and Lantus have not yet been approved for use in pregnancy. Insulin pumps are often used in pregnant patients, allowing an even better glycemic control with less hypoglycemia. An absolute requirement for CSII therapy to be successful is patient education and motivation by an experienced team.

Adult↗