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Biomedical subjects

B Aubert

Publications and source records attributed to B Aubert.

160 records · Page 9Linked to original sources
PubMed1984

Chemoprophylaxis of malaria in non-immune residents in Dar es Salaam, Tanzania.

The malaria infection rates in non-immune residents of Dar es Salaam on various chemoprophylactic regimens were compared with that (37.1%) in those not taking prophylactic antimalarials. Among 647 people resident in Dar es Salaam for 1-6 years the two groups with the lowest infection rates by person-episodes (2.0% and 1.5%) were those taking proguanil 200 mg daily alone or with chloroquine base 300 mg weekly. Infection rates (16.9% and 14.0%) were also significantly lower than in the no-prophylaxis group in those taking chloroquine base 300 mg weekly combined with 'Fansidar', 'Maloprim' (each one tablet weekly), or proguanil 100 mg daily. No significant reduction in the malaria attack rate was found in those taking chloroquine base 300 mg or 600 mg weekly (31.2%), pyrimethamine 25 mg weekly (27.3%), proguanil 100 mg daily (46.4%), maloprim one tablet weekly (40.4%), or a combination of chloroquine base 300 mg weekly and pyrimethamine 25 mg weekly (27.1%). Similar results were obtained when the infection rates per year of exposure were compared. Proguanil was associated with fewest user complaints and fansidar with most.

Adolescent↗
PubMed1983

Physical requirements of a 59Fe bone marrow distribution digital scanning study.

A method is described to provide whole-body scannings of 59Fe bone marrow distribution using a tungsten-alloy collimator. The physical requirements of this method were determined by means of dedicated phantoms. As we were only interested in bounded 59Fe regions (sacral bone, liver and spleen), it was necessary to subtract the 59Fe activity in the blood. An estimate of this activity was obtained by means of 99mTc-labelled erythrocyte whole-body scanning to which a correction factor K was applied. The independence versus depth was performed by computing geometrical means of prone and supine images. The results of these experiments indicate the possible feasibility of a scanning method for a ferrokinetic study in place of the usual external counting.

Bone Marrow↗
PubMed1983

Feasibility of a 59Fe ferrokinetic study based on bone-marrow scans.

The purpose of this study was to evaluate the feasibility of a method that would use 59Fe quantitative sequential scintigrams together with a few blood samples in place of conventional ferrokinetic studies. To quantitate the efficiency of erythropoiesis or iron deposition sites, the radio-iron blood activity was subtracted by means of a whole body scanning with 99mTc-labelled erythrocytes. The study was performed on 31 patients (36 examinations) and regions of interest were drawn by three physicians on the sacral bone, the liver, the spleen and the femoral bone. To assess the physical feasibility of the scintigraphic method, correlation coefficients were computed between the number of counts of the 59Fe and 99mTc images and the corresponding 99mTc and 59Fe activities. To assess the clinical feasibility, the consistency of the data resulting from the drawing of the ROIs was verified and those of conventional ferrokinetics were introduced and their consistency verified. These assessments suggest that the scintigraphic method can be used in place of the conventional external counting method.

Bone Marrow↗
PubMed1983

[Scanography].

Explore the source record for details and available documents.

Brain↗
PubMed1981

Application of x-ray fluorescence to the study of iodine distribution and content in the thyroid.

We have been developing an X-ray fluorescence system designed to determine iodine distribution and content in the thyroid. The X-ray fluorescence unit is composed of a 80 KV X-ray excitation beam and a Si(Li) semi-conductor detector. The angle between the X-ray beam and the axis of the detector is 24 degree. Two single channel analyzers (SCA) are used, the first one corresponding to the K alpha peak and the other to the background. The SCA signals are digitised so that the two corresponding images may be processed using a computer. After subtracting the background, an image is obtained that represents the iodine distribution alone, and the iodine content of the whole thyroid or a part of it can be determined with a reproducibility of +/- 5%. A good correlation (r=0.98) between iodine chemical analysis and iodine fluorescence analysis was obtained for 13 patients.

Humans↗
PubMed1981

[Measurement of intrathyroidal iodine content by X fluorescence: usefulness and application (author's transl)].

X fluorescence quantification of thyroid gland iodine content was performed in 113 subjects. Euthyroid patients averaged 15.6 +/- 4.8 mg in the absence of goiter (18 subjects) and 23.7 +/- 11 mg when the gland was goitrous (11 subjects p less than 0.05). In Grave's disease (28 patients), thyroid iodine content increased significantly (21.7 +/- 11 mg, p less than 0.05. No correlation was found between this parameter and thyroid hormone blood level. During the treatment by carbimazole, patients can be divided in 2 groups; the first group with high initial iodine content (30.3 +/- 15.6 mg 9 patients) decreased it under treatment; on the contrary, the second group with normal initial iodine content (16.9 +/- 7.5 mg 10 patients) increased its iodine content under treatment. No significant difference in T3 and T4 serum levels was found between these two groups. In toxic goiter (6 patients) the initial iodine content was elevated (43.4 +/- 33 mg) and decreased under carbimazole in all the cases. 15 patients with solitary autonomous thyroid nodules were scanned with 99mTc and by X fluorescence imaging. The iodine content of the nodule was 9.9 +/- 4.7 mg; controlateral non suppressed tissue was observed in 11 patients while no 99mTc accumulation was found. The association of these 2 techniques allow to avoid a TSH stimulation test in 70% of the cases. In hypothyroid patients, a low iodine content was found in acquired disease (4.5 +/- 5.6 mg 9 patients); it was increased in congenital hypothyroid goiter. In iodine load (12 patients) the iodine content was increased especially after lymphography. In the initial phase of subacute thyroiditis (11 patients) X fluorescence showed 127I thyroid stores were still normal (14.3 +/- 11.6 mg) while there was no radioactive uptake.

Carbimazole↗
PubMed1977

Comparative study of 111In and 59Fe bone marrow scanning.

The aim of this work is to examine the relative merits of 59Fe and 111In scanning in estimating the functional value of the various erythropoietic areas and in appraising bone marrow distribution and extension. At first we studied a group of patients with heterogeneous distribution of bone marrow secondary to irradiation, ferrokinetics serving a reference for the comparison of 111In and 59Fe scanning. The functional value fo 59Fe scanning was thus proved, in contrast to 111In scanning which was erroneous for 13 of the 29 bone marrow areas studied. A further study of patients presenting polycythemia vera or anemia with 111In demonstrated in some cases false distribution and bone marrow extension. Furthermore, 59Fe scanning permitted evaluation of the efficiency of erythropoiesis and the existence of extramedullary erythropoiesis. Review of the literature revealed that with the activity used there was no dosimetric advantage of 111In over 59Fe.

Anemia↗
PubMedDate not supplied

Treatment of malignant pheochromocytoma with [131I]metaiodobenzylguanidine: a French multicenter study.

Six Medical Centers in France were involved in a prospective study evaluating the efficacy of [131I]metaiodobenzylguanidine (131I-MIBG) in the treatment of malignant pheochromocytoma. Fifteen patients aged from 28 to 75 years bearing tumor sites demonstrating a good MIBG uptake were included in this study. Catecholamines were elevated in 13/14 cases, VMA in 9/14 and metanephrines in 13/14. Two to 11 therapeutic activities of 131I-MIBG were administered, with a mean number of therapeutic doses per patient of 4 and a mean single activity of 4.7 GBq (range 2.9 to 9.25 GBq). Seven patients were alive, and seven patients died 6 to 29 months after their first MIBG administration (mean follow-up of 36 months); 1 patient was lost to follow-up. Two patients had a partial tumor response only, 4 had a hormonal response only, and 3 had both a partial tumor response and a hormonal response (complete in 2 cases). Six patients did not respond to the treatment, 4 of them died. Of the 9 responding patients, 4 relapsed, 3 of whom died subsequently. Haematological toxicity was always transient and mild, except in 1 case.

3-Iodobenzylguanidine↗
PubMedDate not supplied

[131I]metaiodobenzylguanidine therapy in 20 patients with malignant pheochromocytoma.

Twenty patients, 16 male and 4 female (aged 11-76 years), with metastatic pheochromocytoma were treated in our Institution between 1985 and 1990. Metastases occurred in all patients: at presentation in 11 patients, with a 10 to 30 month delay in 7 patients, and 9 and 28 years later respectively in 2 patients. Catecholamines hyperproduction was present in all patients. Metaiodobenzylguanidine (MIBG) uptake was found in 16 patients after a diagnostic dose and only after a therapeutic dose in 1 patient. Surgery was performed on primary tumor (18 patients) and on distant metastases (10 patients). 131I-MIBG therapy was performed in 11 patients, 9 of whom were evaluable. The cumulative activity ranged from 3.7 to 26.3 GBq (100 to 711 mCi) in 1 to 6 courses. We observed symptomatic improvement (5 patients) and partial tumor response in 2 patients, which lasted for 28 and 9 months respectively, terminating with a rapidly progressing disease involving the bone marrow. Stabilisation was observed in 3 patients. Moderate myelosuppression occurred in 4 patients. Fifteen patients died with a median survival of 16 months (range 3-60). Response to therapy was poor and further evaluation of the presently available therapeutic approaches is needed.

3-Iodobenzylguanidine↗
PubMedDate not supplied

[Interactions between complement system and bacterial walls].

The complement system is involved in the antibacterial defence either with a delay, following the specific antibody response, or immediately through a direct interaction between complement components and the bacterial cell wall. Several gram- bacteria initiate the classical pathway through direct interaction between C1 and the lipid A of the lipopolysaccharides; this activation depends upon the structure, the accessibility and the state of polymerization of the lipopolysaccharides. Gram+ and gram- bacteria are able to activate the alternative pathway through a covalent C3b binding. Capsules appear to prevent activation due to their high content of sialic acid, which probably accounts for the virulence. As targets, bacteria may undergo opsonization mainly by C3b, or lysis through transmembrane channels formed by terminal components from C5b to C9.

Bacteria↗