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Biomedical subjects

M Ricard

Publications and source records attributed to M Ricard.

At least 37 records · Page 2Linked to original sources
PubMed1998

Intraoperative localization of neuroblastoma in children with 123I- or 125I-radiolabeled metaiodobenzylguanidine.

BACKGROUND: This study describes a novel method of intraoperative localization of neuroblastoma with a gamma-detecting probe, to detect in situ tumor binding of radiolabeled 123I- or 125I-metaiodobenzylguanidine (MIBG) and improve the quality of tumor resection. METHODS: Fifty-eight children underwent 66 surgical procedures with intraoperative detection of radiolabeled MIBG. All patients with positive MIBG scintiscans at diagnosis were included in the study. A tumor/background ratio exceeding 2:1 at the time of operation was considered positive, indicating a significant uptake of MIBG, compatible with the presence of malignant cells. The surgeons were requested to evaluate the contribution of the method to the surgical procedure. Sensitivity and specificity of the method with either 123I-labeled MIBG or 125I-labeled MIBG, on the basis of correlations between probe findings and pathologic analysis of 288 resected specimens, were determined. RESULTS: Intraoperative detection was helpful in 65% of surgical procedures, allowing a better definition of tumor limits and extension to locoregional nodes or detection of small and nonpalpable tumors in sites with difficult surgical access, especially during operation for relapse. The detection was not contributory in 35% of the procedures (well-localized tumors, thoracic neuroblastoma for technical reasons, highly differentiated tumors as ganglioneuroma, and tumors with mainly necrosis or fibrosis). The sensitivity of 123I and 125I was the same (91% and 92%), but the specificity of 125I (85%) was significantly higher than that of 123I (55%) (p < 0.005). CONCLUSIONS: First, this study demonstrates the feasibility of intraoperative detection, with radiolabeled MIBG, of neuroblastoma in children. We advocate the use of 125I rather than 123I. Second, the method is useful to improve the quality of macroscopic resection in widespread neuroblastoma with nodal involvement, in sites with difficult access, and in operations for relapse.

3-Iodobenzylguanidine↗
PubMed1998

Impact of scatter correction in planar scintimammography: a phantom study.

UNLABELLED: This study examines how scatter correction might affect lesion detection and quantitation of tumor-to-normal breast tissue activity ratio in planar scintimammography. METHODS: Forty-one phantom acquisitions were performed to mimic a wide variety of scintimammographic imaging conditions in which lesions would be close to the chest wall. For each acquisition, the images corresponding to a 10% energy window (110) and two scatter correction methods [the Jaszczak (JA) method and a factor analysis (FA)-based method] were obtained in addition to the conventional 20% image (120). A total of 368 images in which detection of the "tumor" was judged borderline were selected, and 10 independent observers were asked to detect lesions in these images. Receiver operating curve analyses were performed to assess detection performance. Tumor-to-normal tissue activity ratios were calculated for quantitative analysis. RESULTS: Detection performance significantly improved for the I10, JA and FA images compared to the 120 images, with an increase in sensitivity up to 8% for FA images. Sensitivity was especially increased for small lesions (13- and 16-mm3 spheres) and true heart-to-normal tissue activity ratios of > 12. Scatter correction also increased the certainty with which the readers gave their judgment. The tumor-to-normal tissue activity ratio was approximately 8% larger on JA or FA images and 1% larger on the I10 images compared to the 120 images. For a given image, the variability with which this ratio was estimated was reduced by approximately 4% on JA and FA images. CONCLUSION: Based on these phantom results, scatter correction might be used with benefit in scintimammography.

Breast↗
PubMed1997

The acquisition of personal pronouns in French-speaking and English-speaking children.

This paper presents a longitudinal study on the acquisition of first, second, and third person pronouns in twelve French-speaking and twelve English-speaking children. Comprehension and production data were collected every two months, beginning when the subjects were aged 1;6 and ending once pronouns were fully acquired. Three hypotheses concerning the rules children develop in learning pronouns were tested: (1) the person-role hypothesis (Charney, 1980), (2) the speech-role hypothesis (Clark, 1978), and (3) the name hypothesis (Clark, 1978). An analysis of children's pronominal confusion when they were addressed listeners as well as when they were non-addressed listeners was performed. The results indicated that the mastery of pronouns did not follow the developmental sequence predicted by the speech-role hypothesis; they provided evidence for the person-role hypothesis only when children were speakers, and partially supported the name hypothesis. The data also suggested that pronominal confusion is not a rare phenomenon among children tested in a non-addressee context. Finally, effects of child gender and native language were observed. Possible interpretations of the data discussed.

Analysis of Variance↗
PubMed1997

Digital superimposition of CT and positive SPECT tumor images. Phantom study and clinical applications.

Digital superimposition of SPECT and CT data was evaluated in a phantom and then applied to patient data. Seven patients were studied. Six patients had pheochromocytomas as evidenced by I-131 or I-123 MIBG localization and one had ovarian cancer imaged by In-111 OC125 MoAb. Anatomic or skin landmarks identified the level of each SPECT transaxial slice. Both SPECT and CT image data sets were transferred to a minicomputer connected to an image processor. Afterwards, a scaled, rotated and translated realignment was performed. Data for each modality were coded in different primary colors and then superimposed. Superimposition of phantom data was checked for the absence of distortion of pinpoint and large structures. For suspected tumor sites, superimposition of the patients' slices were allowed to check for matching SPECT and CT abnormalities to localize a SPECT abnormality without a corresponding CT lesion or to distinguish SPECT abnormalities from those seen on CT. In one case, the technique failed because of very low I-131 MIBG-tumor uptake. The superimposition decreases false positives in SPECT and both false negatives or false positives in CT.

Adolescent↗
PubMed1997

[Peroperative detection probes. Evaluation and perspectives in endocrinology].

The principal primary endocrine tumors may be visualized scintigraphically by injection of highly specific radiopharmaceuticals. When surgery is indicated, the surgeon may be assisted in difficult cases by a probe detecting the radioactivity concentrated in tumoral tissue. A radiopharmaceutical consists of a vector molecule labeled with a radioactive isotope. Only radioactive emissions with a certain half life and energy are suitable for intraoperative detection; this limits the number of usable radionuclides. In practice, one uses iodine 123 (123I), iodine 125 (125I), and iodine 131 (131I) labeled metaiodobenzylguanidine mIBG or indium 111 (111In) labeled pentetreotide (Octreoscan) or bi-specific anti CEA antibody. During intra-operative detection, the probe is closely positioned to the tumor-tissue which is surrounded by radioactive background activity due to the non-specific binding in adjacent organs. In order to work with probes that are easily handled, and sensitive at the same time, one can opt for technology which uses either diodes or scintillating crystals. These probes can be used at room temperature and their choice depends upon the energy to be detected. Interesting results begin to be published concerning pheocyromocytomas, differentiated thyroid carcinomas, gastro-entero-pancreatic tumors and medullary thyroid carcinoma, especially for reintervention when conventional imaging modalities fail to localize tumors.

3-Iodobenzylguanidine↗
PubMed1996

Effects of the phenylurea herbicide isoproturon on periphytic diatom communities in freshwater indoor microcosms.

The toxic effects of the phenylurea herbicide Isoproturon -IPU: (3-(4-isopropylphenyl)-1, 1-dimethylurea)-were studied on the colonization of periphytic diatom communities, within indoor microcosms consisting of a mixed biotope (water column and natural sediment) and two biological species-rooted macrophyte cuttings (Elodea densa) and benthic bivalve molluscs (Corbicula fluminea). The periphyton, essentially composed of diatoms, was collected on artificial substrata (glass slides) in the upper layers of the water column, after two periods of exposure (34 and 71 days). IPU was initially added in the water or in the sediment compartment, at two nominal concentrations (L1 and L2 levels) for each contamination source-5 and 20 microg litre(-1) and 100 and 400 microg kg(-1) in sediment (w/w) respectively. The effects of IPU on the density and community structure of periphytic diatoms are described. A marked reduction in the diatom density was observed after 34 days exposure to the lower concentration of IPU in the water (5 microg litre(-1)). For the L2 levels, the very small number of live cells present did not permit quantification of the diatom density. After 71 days, recovery in community parameters occurred for the two contamination levels of the sediment and water column sources. Samples collected in the experimental units contaminated with the L2 levels were dominated by heterotrophic and smaller diatom species, such as Sellaphora seminulum. Data treatment based on factorial discriminant analysis enabled us to distinguish the different contamination conditions, with only 11 species from the 130 taxa identified.

Journal Article↗
PubMed1996

Radioactive iodine treatment and external radiotherapy for lung and bone metastases from thyroid carcinoma.

UNLABELLED: We assessed the therapeutic benefits of 131I treatment in patients with distant metastases of differentiated thyroid carcinoma. METHODS: Of 2200 patients treated for differentiated thyroid carcinoma at our institution, 394 had lung and/or bone metastases. RESULTS: Two-thirds of the patients had 131I uptake in their metastases, but only 46% achieved a complete response. Prognostic factors for complete response were: younger age, presence of 131I uptake in the metastases and small extent of disease. The survival rate was 33% at 15 yr. As shown by multivariate analysis, favorable prognostic factors for survival were: younger age and time of metastases detection, well-differentiated histologic type of the thyroid tumor, presence of 131I type uptake in the metastases, small extent of the disease and year of discovery of metastases. CONCLUSION: In terms of survival, the benefits of 131I therapy cannot be demonstrated by prospective controlled studies. The present study clearly demonstrates, however, that treatment with 131I is one of the factors which accounts for survival; patients whose metastases concentrated 131I and who could be treated with radioiodine had higher survival rates. Patients who achieved complete response following treatment of distant metastases had a 15-yr survival rate of 89%, while those who did not achieve complete response had a survival rate of only 8%. The survival rate improved with the year of discovery of distant metastases, after 131I total-body imaging and serum thyroglobulin measurements were routinely used.

Adenocarcinoma, Follicular↗
PubMed1996

Iodine concentration by the thymus in thyroid carcinoma.

A 14-yr-old boy underwent a total thyroidectomy with bilateral neck dissection for a papillary carcinoma with lymph node metastases. Total-body scanning with 3.7 GBq 131I revealed radioiodine accumulation in the anterior mediastinum. CT and MRI demonstrated a mediastinal mass which corresponded to the area of increased radioactivity. Five months later, another therapeutic dose of 131I was followed by a sternotomy and removal of the thymus because a hand-held radiodetecting surgical probe demonstrated that the thymus was the mediastinal structure which concentrated iodine. Thymus histology was negative for thyroid cancer metastases (as further confirmed by the negative immunostaining) and showed cystic Hassall's bodies. Secondary ion mass spectrometry microscopy demonstrated that iodine was located only in the Hassall's bodies, bound to proteins. This finding suggests that an acquired "thyroid follicle-like" structure, as that observed in cystic Hassall's bodies, could be responsible for the epithelial cell iodine uptake. In conclusion, we have provided evidence for the iodine-trapping property of the cystic Hassall's bodies of the thymus, which may be a possible cause of misleading mediastinal radioiodine uptake.

Adolescent↗
PubMed1995

Radioiodinated metaiodobenzylguanidine in neuroblastoma: influence of high dose on tumour site detection.

For more than a decade radioiodinated metaiodobenzylguanidine (mIBG) has been commonly used for neuroblastoma imaging. The accuracy of this scintigraphic method in detecting both primary and secondary tumour sites is crucial when evaluating the extent of disease. The aim of our study was to assess the impact of high-activity mIBG scintigraphy on neuroblastoma staging. Eighteen scans (TS) were obtained in 15 children after a therapeutic dose of iodine-131 mIBG and compared to diagnostic mIBG scans (DS) (in eight cases with 131I-mIBG and in ten cases with 123I-mIBG). The superiority of TS over DS was confirmed by the overall results: a total of 220 lesions were disclosed with TS and 171 with DS. However, in only one case did the TS findings, namely skeletal involvement not evidenced on corresponding DS, have an impact on clinical staging. In contrast, neither TS nor DS detected proven bone involvement in four patients. The dose-related sensitivity of mIBG scintigraphy in detecting neuroblastoma tumour sites was confirmed. The ultimate impact of high-dose scans on neuroblastoma management, however, seems limited.

3-Iodobenzylguanidine↗
PubMed1994

Verapamil-reversing concentrations induce blood flow changes that could counteract in vivo the MDR-1-modulating effects.

BACKGROUND: Intraarterial hepatic (IAH) administration of verapamil should achieve mdr-1-reversing concentrations with reduced cardiac toxicity. The authors have explored the tolerance of its IAH administration and its effects on doxorubicin pharmacodymamics. METHODS: Verapamil was given to rabbits by intravenous or IAH administration, and its effects on heart rates were compared. Doxorubicin then was given intravenously either with IAH verapamil or with an IAH control perfusion, and tumor and liver drug concentrations were determined. Hepatic blood flow changes were studied by the administration of 99mTc-albumin macroaggregates (99mTc-MAA) under verapamil IAH perfusions. RESULTS: Compared with the intravenous route, IAH administration of verapamil was not toxic, and cardiac effects were reduced significantly. Its effect on doxorubicin distribution was detrimental, because the tumor-liver doxorubicin concentration ratios were lower in the verapamil group (0.23 vs. 3.37; P < 0.05). Tumor doxorubicin concentrations were lower when verapamil was coinfused (43 vs. 573 ng/100 mg tissue; P < 0.05). In normal liver tissue, increased amounts of doxorubicin and metabolites were observed. The verapamil IAH perfusions with 99mTc-MAA confirmed a differential action on tumor and normal vessels; the distribution of radionuclide was diverted away from the tumor bed significantly when verapamil was administered (tumor-to-liver ratio of 25.3 control rabbits vs. 5.99 rabbits who received verapamil; P < 0.05). CONCLUSIONS: Reversing the concentrations of verapamil provoked changes in the distribution of the liver blood flow. The hemodynamic effects of verapamil regional perfusions could counteract in vivo its potential mdr-1-reversing properties.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Intraoperative detection of pheochromocytoma with iodine-125 labelled meta-iodobenzylguanidine: a feasibility study.

We evaluated the feasibility of intraoperative detection of pheochromocytoma sites after injection of meta-iodobenzylguanidine labelled with iodine-125. Six patients with multiple or recurrent pheochromocytoma were injected for intraoperative detection. During surgery, all count rates were recorded using a CdTe detector diode. Tumour foci were found in all cases. Tumour count rates ranged from 50 to 1000 counts per second (mean approximately 400). Blood activity, used as a reference level, ranged from 10 to 50 counts per second (mean approximately 35). In all patients, the intraoperative probe was helpful to the surgeon and facilitated the discovery of the pathological foci even when they were small (< or = 1 cm). Complete resection under probe control was correlated with postoperative normalization of urinary normetanephrine excretion. The use of a probe designed to detect low-energy gamma-ray radionuclides bound to a highly specific molecule provides an accurate detection tool which is well adapted for ectopic localizations and for small foci.

3-Iodobenzylguanidine↗
PubMed1993

Potential contribution of 131I-labelled monoclonal anti-CEA antibodies in the treatment of liver metastases from colorectal carcinomas: pretherapeutic study with dose recovery in resected tissues.

20 patients with liver metastases from colorectal carcinoma undergoing laparotomy received 15-60 mg intravenously, either intact or fragments of, anti-carcinoembryonic antigen (anti-CEA) monoclonal antibodies labelled with 0.55-1.48 GBq (15-40 mCi) of 131I, 3-8 days prior to operation. The uptake measured per gram of metastases ranged from 0.33 to 6.6 x 10(-3%) of injected dose. Tumour to liver uptake ratios ranged from 2 to 33. The radiation dose, estimated in 6 patients (3 of each group), for an extrapolated dose of 3.7 GBq (100 mCi) of 131I ranged from 0.3 to 0.8 Gy in normal liver or spleen (an acceptable estimate for bone marrow radiation dose) and from 3.4 to 8.2 Gy to the hepatic metastases, indicating that probably other therapeutic modalities should be associated with radioimmunotherapy.

Antibodies, Monoclonal↗
PubMed1993

The reaction of 9- to 10-month-old infants to an unfamiliar animal.

In an attempt to assess infants' reactions to one particular class of animate objects (animals), as opposed to persons and inanimate objects, 57 babies between 9 and 10 months old were divided into three equal groups and assigned to three experimental conditions, involving (a) a living unfamiliar dwarf rabbit, (b) a novel toy, or (c) an adult stranger. The same infant-controlled procedure was used in all conditions, and the infants' reactions were measured in terms of approach and stimulus- as well as mother-directed looks, smiles, and vocalizations. Results showed that the animal provoked an intermediate reaction, consisting of a combination of behaviors elicited by the inanimate object (i.e., quick proximity seeking, contact, and scarcity of smiles) and by the person (i.e., strong and lasting attention). Implications of these results for clarification of the infant's concept of animal was discussed.

Concept Formation↗
PubMed1993

A comparison of temperature rise in human calf muscles following applications of underwater and topical gel ultrasound.

For ultrasound to be effective, a conducting medium must be placed between the soundhead and the skin. Little research has been performed to test whether or not these mediums actually work. The purpose of this study was to compare the effect of tap water immersion and ultrasound gel conducting mediums on tissue temperature rise in the human leg. A 23-gauge hypodermic needle microprobe was inserted 3 cm deep into the medial portion of the gastrocnemius muscle of 20 subjects. Each subject participated in two random order treatments using tap water immersion and topical gel conducting mediums. Each treatment consisted of continuous ultrasound delivered topically at 1.5 W/cm2 for 10 minutes. During both treatments, the soundhead was moved at a speed of 4 cm per second, and the temperature was recorded every 30 seconds. A significant difference was found between the two treatment methods [t(19) = 9.18, p < .001]. The topical gel increased tissue temperature 4.8 degrees C, whereas the underwater treatment increased tissue temperature only 2.1 degrees C. Therefore, at a tissue depth of 3 cm, ultrasound gel is a better conducting medium than water. Also, the authors discovered that it took nearly 8 minutes for the temperature to reach therapeutic levels during the gel technique. These findings should be of clinical significance to clinicians who regularly use ultrasound.

Adult↗
PubMed1992

Immunoscintigraphy in Hodgkin's disease and anaplastic large cell lymphomas: results in 18 patients using the iodine radiolabeled monoclonal antibody HRS-3.

Immunoscintigraphy (IS) using the HRS-3 Hodgkin associated monoclonal antibody (MoAb) was performed in 18 patients with Hodgkin's Disease (HD) at staging or restaging. Either F(ab')2 fragments (14 patients) or whole HRS-3 (4 patients) labeled with 77-260 Mbq 131-I were used. Whole body images, including anterior and posterior views, were taken from a digital gamma camera, within 4 to 8 hours after injection and then daily for 5 days. In one patient IS was discontinued due to iodine intolerance. Seventeen patients were evaluable: 14 showed a true positive result including 2 cases which were reviewed as anaplastic large cell lymphoma (ALCL). Nodal, splenic, bone marrow and muscle involvements were imaged, many of these sites were previously unsuspected. In 7 patients with true positive findings the Pressman Specificity Index, as measured from biopsied material, ranged from 1.5-3 in 4 patients and from 5 to greater than 100 in 3 patients. Imaging was equivocal or failed in 1 patient (lymph nodes). In 2 patients, IS imaging was truly negative due to the absence of active HD, and a false negative result occurred once (inguinal node). In none of the patients a false positive image was observed. In order to rule out non-specific iodine uptake a control, anti-ACE MoAb, labeled with 125-Iodine was injected simultaneously in 10 patients. The evaluation of the study gave a sensitivity of 87% and a good specificity. IS using radioiodine labeled MoAbs is feasible and represents a reliable non-invasive diagnostic method for the staging and follow-up of HD and ALCL.

Animals↗
PubMed1992

[Mother-infant interaction and the origin of self awareness in the nursing infant].

The mother is the principal care-giving partner of the infant and an important source for the development of self-awareness and self-esteem. The importance of the early relational experiences of the nursing infant with its mother has been widely emphasized by the psychoanalytical approach. Through this special interaction with the parent, the infant gradually internalized images leading to the individuated self and to self-love. The purpose of this paper is to present succinctly some of the broad theoretical positions regarding the forming of the self in the nursing infant, first within the "classical" psychoanalytical current, then under the impact of more recent research in experimental psychology which have given rise to new syntheses. Empirically, the capacity for self-recognition may be observed during early childhood by means of a child's reactions in front of the mirror; therefore, the work dealing with this phenomenon will be discussed briefly.

Breast Feeding↗
PubMed1991

[Biodistribution of murine XF-8 monoclonal antibody in patients with colonic cancer].

We describe a biodistribution study using a radiolabelled anti-tumor murine monoclonal antibody F(ab')2 in XF-8 in 6 patients with colorectal carcinoma. One patient had an isolated rectal carcinoma. Five patients had hepatic metastasis of colorectal carcinoma. Among them three had also the primary colorectal carcinoma. Double-label method using simultaneous injection of 131-Iodine monoclonal antibody XF-8 F(ab')2 and 125-Iodine control monoclonal antibody was performed to evaluate the specificity of monoclonal antibody localization in the tumor. Each patient received 4-8 mCi of 131-I XF-8 F(ab')2 infused at doses 0.5-5 mg. Simultaneously 200 microCi of 125-I non relevant antibody were infused. Before each administration, immunoreactivity of antibodies preparations was checked before labelling by immunohistological methods and, after labelling, by cell-binding tests. In biodistribution studies, patients were scanned with a scintillation camera each day since the infusing day to the surgery day (3-6 days). To study specificity of XF-8 F(ab')2 antibody localization we measured by means of scintillation counting in tumors and normal tissues recovered after surgery. In vitro immunoreactivity of monoclonal antibody batches was safe. All our data in vivo are negative but correlated. We concluded that criteria for screening the monoclonal antibodies considered for detection of human tumors are not really known.

Adult↗