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Biomedical subjects

D Ducassou

Publications and source records attributed to D Ducassou.

At least 91 records · Page 5Linked to original sources
PubMed1982

[Comparison of platelets frozen with different cryoprotective agents].

A comparative study was performed on platelets frozen with dimethyl-sulfoxide (D.M.S.O.), glycérol and dimethyl-acetamide (D.M.A.C.). The results of tests realized in vitro (platelet yields after thawing platelet aggregation, hypotonic stress, release of enzymes and ultrastructure), and in vivo (life span and recoveries after transfusion) have clearly shown that D.M.S.O. is the best cryoprotective agent. The results obtained with glycerol were less interesting and more clinical data are needed in order to study the hemostatic effectiveness of platelets preserved with this agent. Dimethyl-acetamide gave the worse results and in our opinion, must not be used for the cryopreservation of platelets.

Acetamides↗
PubMed1982

ESCA studies on heparin-like materials used for extracorporeal shunts.

Amino-acids sulfamide substituted polystyrene surfaces exhibit an heparin-like activity. Similar treatments were achieved on small diameter tubings made of polystyrene grafted on polyethylene. Electron spectroscopy for Chemical Analysis (ESCA) appeared as the suitable method for a chemical characterization of the surface (approximately 50-100 A depth) to be in contact with circulating blood. These tubings were implanted as extracorporeal shunts on dogs. The variations of local concentrations of labelled platelets, red cells and fibrinogen were recorded in situ. Depending on the conditions of preparation and implantation, a slight adhesion of platelet was observed. By using such type of materials with an improved mechanical compliance, small diameter antithrombogenic tubings could be developed, provided the chlorosulfonation prior to amino-acid grafting is mild.

Animals↗
PubMed1981

[Clinical and laboratory features of endemic goiter in the Man region (Ivory Coast) (author's transl)].

An epidemiological study involving 616 subjects carried out in the Man region, Côte d'Ivoire, showed endemic goiter in 54,5% of the group overall and in 80% of females. Thyroid function of subjects chosen at random in the goitrous and non-goitrous group (105 G and 71 NG respectively) was identical. Compared with a French control group T4 was significantly lower but T3 and TSH were higher. TBG level is high with low iodine elimination. High levels of TSH are not necessarily associated with low T3 or T4 levels, or with clinical signs of a hypothyroid condition. They are probably the result of a transient reaction. T4-TSH and T3-TSH correlations for NG subjects were (-0,40) but the T3-TSH correlation for the G subjects was significantly lower (-0,23). These differences could be explained by the simultaneous high levels of T3 and TSH more frequently rencountered in G subjects and by the fact that serious hypothyroid conditions are more frequent in the NG group (6 out of 9). The percentage of hypothyroid conditions is high in both clinical and biological investigations. No anti-thyroglobulin antibodies were found in any of the hypothyroid cases with goitre. The histograms illustrate the clinical and biological heterogeneity of a homogeneous non-medicalised population.

Adolescent↗
PubMed1981

[Radioimmunological assay for antithyroglobulin antibodies, with the use of staphylococcal protein A as separating agents (author's transl)].

The staphylococcal cell wall protein A is known to bind specifically and rapidly to most of human immunoglobulin G. We have utilised this immunoadsorbent in a radio-immunoassay for antithyroglobulin antibodies (anti-Tg), to separate autoantibodies-125I thyroglobulin complexes from free 125I thyroglobulin (125I Tg). There was no specific precipitation of 125I Tg in the presence of 95,6% of sera from normal subjects (N = 45). In graves' disease, 56/65 hyperthyroid patients sera were positive, and so were 12/13 sera from patients with primary hypothyroidism. This assay showed a good correlation with the second antibody method, while much more rapid and slightly more sensitive. Compared with the new assay, the red cell agglutination test exhibited a high frequency of false negative results. This rapid, sensitive and inexpensive method provide an easy and reliable tool to screen sera acceptable for thyroglobulin measurement.

Antibodies↗
PubMed1981

[Metalloporphyrin study in experimental carcinology (author's transl)].

Antitumoral effects and intratumoral concentrations of a metalloporphyrin were studied in mice with solid chemo-induced or transplanted tumors. The synthesis of this molecule was realised both with a stable metal (TPPS4SnCl2) (TPPS4InCl) and a radioactive metal (TPPS4(113)SnCl2) (TPPS4(111)InCl). The metal is introduced into the tetrapyrollic structure to give this molecule very high stability. The effect of the stable metalloporphyrin on tumoral kinetic parameters was analyzed. No tumoral regression was observed during the various experimental procedures. Even though radioactive molecules were found in the tumours, they were also present as high concentrations in the liver, spleen and kidneys, more than 72 hours after injection. Results are compared with those of various authors who used a molecule without metal, levels being measured by fluorescence in various organs and in the tumors. The interest of this metalled molecule in carcinology is discussed in relation to these new results.

Animals↗
PubMed1980

Emission and transmission brain tomography.

Comparative emission and transmission brain tomograms were obtained in 209 patients to establish the diagnostic accuracy of a new emission tomographic scanner in detecting space-occupying disease in the brain. Concordant results were obtained in 169 patients (81%). Computed transmission tomography (transmission CT) yielded an overall rate of false-positive results of 0.48% and a false-negative rate of 6%. Emission CT yielded a false-positive rate of 0% and false-negative rates of 2.4% for malignant disease and 10% for vascular disease. The higher rate of false-negative results for vascular disease with emission CT occurs because transmission CT can detect old infarction. The rates of detection of recent vascular disease with emission and trnasmission CT are identical. Thus emission CT is highly sensitive in detecting space-occupying disease in the brain. It represents an ideal screening procedure.

Brain↗
PubMed1980

Unscheduled DNA synthesis in psoriatic skin after ultraviolet irradiation and the effects of a combined treatment with 8-methoxypsoralen and longwave ultraviolet radiation: a clinical study.

Biopsies were taken from psoriatic patients undergoing photochemotherapy and then studied by autoradiography to investigate possible unscheduled DNA synthesis (UDS) following 8-MOP photodamage in epidermal cels. No sparse labelling was found in seventy samples taken from twenty-four different patients during PUVA therapy, indicating a lack of UDS. In contrast, UDS was observed in three patients irradiated with an all-spectrum UV lamp, as a test for DNA damage and excision repair activity. The incorporation of 3HTdR in these keratinocytes which were not undergoing S-phase was not affected by the dose of UV-A received during different stages of PUVA treatment. The results are discussed in terms of repair of the induced photodamage at the level of DNA, and in relation to a possible risk of this treatment when it is given over a long period of time.

Adolescent↗
PubMed1980

New radioisotopic method for evaluation of the healing potential of a fracture.

A new radioisotopic method for the evaluation of the healing potential of a fracture is developed in this paper. The centromedullary circulation in the bone is visualized under general anaesthesia by means of pertechnetate 99TcmO4 injected into the distal metaphysis of the tibia. Twenty-two patients with an average age of 25 years have had this examination. All suffered from a fracture of the leg with a worrying evolution. Isotopic osteomedullography has shown that the resumption of centromedullary circulation was the most favourable factor for good healing of the fracture. When the examination is positive, it seems advisable to wait until the focus is healed even if the clinical and/or radiographic survey are not in accordance, but when there is no resumption of the centromedullary circulation a pseudoarthrosis may well result. As the reliability of this technique is satisfactory, it should be used when doubt remains about healing of a fracture.

Adult↗
PubMed1980

[Study of endocytosis in mouse peritoneal macrophages using colloid particles labelled with Technetium 99 m].

Endocytosis of radioactive technetium colloïd by murine peritoneal macrophages cultures is measured after incubation. The results show a time and temperature dependant phenomen, reduced by hydrocortisone and inhibitor of glycolysis (NaF). Cytochalasine B and colchicine have no effect on the uptake of Technetium sulfur colloïd. These results suggest that the pinocytosis of technetium colloïd is independent of the actions of microfilaments and microtubules.

Animals↗
PubMed1980

[Thyroxin binding globulin (TBG) radioimmunoassay. Normal patients results according to age, and sex, and in the cases of dysthyroidisms (author's transl)].

The value of TBG serum concentration for the exploration of thyroid function was studied by radioimmunoassay in 203 patients (133 normals, 62 dysthyroidism, 8 women taking oral contraceptives). The results of the normal patients show important and as of yet unexplained variations of TBG levels, depending on age and sex. In hyperthyroidism, serum TBG was reduced significantly in women and no significantly in men. In hypothyroidism, the levels are significantly high in both sexes. Like the TRH test, the TBG serum concentration determination may be helpful for the diagnosis of a slight hypothyroidism. Moreover, as the serum levels return to normal values with substitutive therapy, TBG assay may be used as a follow-up test during the treatment of hypothyroid patients.

Adult↗
PubMed1980

[Growth kinetics statistical analysis of chemo-induced carcinomas and sarcomas in mice (author's transl)].

An experimental model allowing comparative studies of growth kinetics of autochtonous tumours with differentiated histology was investigated. Epithelial and mesenchymal tumours were chemically induced in mice. The distribution of parameters defining the growth of these two tumour types was first studied. Then, the correlations were calculated between the three following paired parameters: doubling times, defined during the whole growth period, latent tumoral period and survival times. The results confirmed the initial hypothesis that tumour growth kinetics were related to histological character. The study showed that there was a significant difference between growth rates, maximum sizes and survival delays respectively presented by sarcomas and carcinomas. Owing to the slow growth rate of these autochtonous tumours, this experimental model is a very interesting tool to investigate various therapeutic protocols for human beings.

Animals↗