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Biomedical subjects

M Ricard

Publications and source records attributed to M Ricard.

52 records · Page 3Linked to original sources

Immunoscintigraphy of Hodgkin's disease: in vivo use of radiolabelled monoclonal antibodies derived from Hodgkin cell lines.

The Hodgkin associated monoclonal antibody (Mab) HRS-1 reacts with Hodgkin and Reed-Sternberg cells (HR-S) in all HD subtypes. HRS-1 Mab was labelled with radioiodine and injected into 10 patients for immunoscintigraphy (IS). Seven patients were injected with HRS-1 Mab radiolabelled with 131I and three patients were injected with HRS-1 Mab labelled with 123I. A control anti-alpha-fetoprotein (anti-AFP) Mab was radiolabelled with another iodine isotope and was injected simultaneously in five cases. Six out of eight patients with proven HD had a true positive scan (nodal, splenic and bony involvement). Imaging was equivocal or failed in the two other patients. In the last two patients IS imaging was truly negative due to the absence of residual HD in one patient and to an erroneous histological diagnosis of HD in another patient. These results, although preliminary, demonstrate that IS with radioiodine-labelled HRS-1 Mab is feasible and may prove to be informative in the staging of HD.

Animals↗

Positive anticalcitonin immunoscintigraphy in patients with medullary thyroid carcinoma.

A cocktail of three monoclonal F(ab')2 fragments against three distinct epitopes of calcitonin or PDN 21 was labelled with either 111In or 131I. These F(ab')2 fragments, a control 125I-F(ab')2 fragment and 99mTc-pertechnetate were injected into four patients suffering from medullary thyroid carcinoma. Scintigraphy data were processed by energy factor analysis for an optimal separation of images corresponding to each isotope. The best tumor detection was obtained 1-3 days after injection of the 111In-F(ab')2 cocktail which clearly labeled the thyroid tumors in the four patients (smallest tumor detected, 0.6 cm) as well as lymph node and bone metastases. In the liver, positive detection was only successful with the 131I-labeled cocktail. These results were confirmed by counting rates of resected specimens which provided average specificity indices ranging from 3.3 to 13.1. Anticalcitonin antibodies could be particularly useful for immunoscintigraphy detection of residual or recurrent medullary thyroid carcinoma in patients with elevated calcitonin serum level.

Adolescent↗

[In vivo imaging of Hodgkin's lymphomas using monoclonal antibodies].

The Hodgkin- and Reed-Sternberg cell associated monoclonal antibody HRS-1 was labeled with radioactive iodine and injected into 6 patients with Hodgkin's lymphoma for immunoscintigraphic imaging. Four of five patients who received 131I-labeled HRS-1 had a positive immunoscintigram. In the sixth patient, the HRS-1 Mab was labeled with 123I in order to utilize tomoscintigraphy instead of linear scintigraphy. Bony disease was demonstrated by immunoscintigraphy in this patient. These preliminary results demonstrate that immunoscintigraphy with iodine-labeled HRS-1 Mab is feasible and informative in Hodgkin's lymphoma. The real clinical value of immunoscintigraphy in Hodgkin's lymphoma must be determined in a larger series of patients. Several modifications of the technique such as the use of Fab or F(ab')2 fragments should further improve the results.

Adolescent↗

[Quantitation of iodine by analytical ion microscopy (AIM)].

AIM allows imaging and quantification of all elements on a biological tissue section. However quantification is limited by physical parameters which are difficult to assess and which intervene for a given element in the relation between its concentration and the measured signal. Thus, to quantify iodine in thyroid follicles, an iodine standard was prepared. Homogeneity in its atomic iodine distribution was tested by surface and depth analyses. Then, a standard curve was generated to be used as a reference for quantification of iodine on histological preparation by AIM.

Iodine↗

Therapeutic use of 131I-metaiodobenzylguanidine (MIBG) in neuroblastoma: a phase II study in nine patients.

Effects of high activities of I 131 meta-iodobenzylguanidine (mIBG) were evaluated in nine children with advanced neuroblastoma. All patients had been previously heavily treated and had either primarily refractory disease or resistant relapse. Twenty-two doses of mIBG labeled with 1.3 to 4 GBq (35-108 mCi) of iodine 131 were administered. Three subjective effects, especially relief of pain, and two objective effects were observed. Transient blood pressure increase was observed once and did not recur after prolongation of the infusion time to 6 hours. A major side effect was bone marrow toxicity, essentially marked by thrombopenia, particularly severe in previously bone-marrow-transplanted patients.

3-Iodobenzylguanidine↗

Prospective comparison of ultrasound and computed tomography in the evaluation of the size of the uterus: can these methods be used for intracavitary treatment planning of carcinoma of the uterus?

A prospective evaluation of computed tomography and ultrasound was performed on 34 patients with Stage I and II endometrial carcinoma. All patients underwent immediate surgery following intracavitary treatment directed to vaginal mucosa. Pathologic measurements of the uterus were compared to those obtained by imaging technologies. The results of the study suggest that all but height measurements were rather accurately determined by both ultrasound and CT scan. However ultrasound was significantly better in determining the size of the cervix. Therefore ultrasound measurements could be used routinely for intracavitary treatment planning in endocervical carcinoma and endometrial carcinoma.

Brachytherapy↗

[Value of total thyroxine determination by fluorescence polarization in examination for dysthyroidism].

Total T4 has been measured by fluorescence polarization (Abbott TDX). The intra-assay variation coefficient is three fold smaller than that obtained by radioimmunoassay (T4 RIA). The interassay variation coefficient of T4 TDX (7%) is better than that of T4 RIA (9%). There is a strong correlation between the two methods (r = 0,95). The mean value of T4 TDX is significantly lower than that of T4 RIA in 218 euthyroid patients without treatment as well as in 92 euthyroid patients under T4 treatment and in 14 hypothyroid patients. In 30 hyperthyroid patients the mean values were identical. The automatization and the short time of manipulation (0,5 hour) allow to obtain the result during the consultation.

Fluorescence Polarization↗

Electrets for use as dosimeters in radiography.

A compact device for the manufacturing of electrets and for the measurement of the dose to the skin of the patient in radiography has been developed and described. The surface potential of a polarized polymer electret decreases when it is exposed to radiation. The measurement of the variation in surface potential appears to be a reliable method for the evaluation of the dose. The electret does not disturb the examination nor the radiographic image as it can be given tissue equivalent properties.

Humans↗

[The marine diatom Chaetoceros simplex calcitrans Paulsen and its environment. Effects of light and ultraviolet irradiation on the biosynthesis of fatty acids].

In continuous light (24/24 h) or with a 12/24 h photophase, the title diatom synthesizes the same total amount of fatty acids. But the photophase considerably increases some of them: C 18:2 (+535%), C 17:2 (+422%), C 17:0 (+97%), C 19:0 (+97%), C 17:1 (+72%). Adding ultraviolet irradiations to the two mentioned conditions of light also increases the total amount of fatty acids and induces the biosynthesis of the C 20:0. The results are discussed.

Animals↗

Process of cellular division in Escherichia coli: physiological study on thermosensitive mutants defective in cell division.

Thermosensitive fts mutants of Escherichia coli belonging to seven previously identified genetic classes (ftsA to ftsG) were studied from a physiological standpoint. These mutants immediately stopped dividing and formed multinucleated filaments when the temperature was shifted to 41 C. Macromolecular syntheses (deoxyribonucleic acid), ribonucleic acid, cell mass, and murein) continued exponentially for at least 40 to 120 min. The number of surviving bacteria remained constant during the time of incubation, and this number began to decrease exponentially, as the rate of cell mass increase leveled off from the initial rate. The recovery of cell division at 30 C in these filamentous cells was studied after 60 min of incubation at 41 C. The existence of three types of mutants was shown. The ftsA and ftsE mutants resumed cell division without new protein synthesis; ftsD mutants resumed cell division only if new protein synthesis occured, while ftsB, C, F and G mutants did not resume cell division at all. No alteration in the cell envelope was detected by the method used here, although the ftsA, B, D, F and G mutations, in contrast with ftsC and E, caused an increased resistance to penicillin G. It was also shown that the recA mutation did not suppress the effect of the fts mutations and that none of the lysogenic fts mutants induced prophage multiplication while forming filaments. The effects of osmotic pressure and salts which rescue the mutant phenotype is described.

Bacterial Proteins↗