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Biomedical subjects

P Bourguet

Publications and source records attributed to P Bourguet.

At least 19 recordsLinked to original sources
PubMed2006

[Use of PET for evaluation of treatment response in oncology].

18FDG -PET is now usually included in the treatment strategy, for the staging or the diagnosis of recurrence. In lymphoma, PET is well documented for evaluation of tumour response. For solid tumours, despite good published results, the accuracy of PET has to be confirmed by large series of patients. A good interpretation of PET needs a SUV analysis. New radiotraceurs of the nuclear synthesis could certainly improve the accuracy of response evaluation by PET.

Fluorodeoxyglucose F18↗
PubMed2006

[2005 monitoring report: use of positron emission tomography with fluorodeoxyglucose in the management of patients with breast cancer, ovarian cancer, and uterine cancer].

CONTEXT: The validity of the recommendations is based on their actualisation as well as on the quality of the initial elaboration process. Therefore the "Standards, Options and Recommendations" (SOR) from the National French federation of comprehensive cancer centres (FNCLCC) has set up a literature monitoring process. OBJECTIVES: To identify new data, which are likely to modify existing recommendations, evaluate their impact and inform potential users on their validity. METHODS: The monitoring process is based on 3 main steps lead in collaboration with experts: collect data, select and classify information and analyse information. Analysis of information consists of comparing the conclusions of new data with the conclusions of the initial report and then to identify the recommendations that need to be updated. RESULTS: This article presents the 2005 monitoring report concerning "the use of positron emission tomography with FDG in the management of breast cancer, ovarian cancer and uterin cancer". Following the monitoring process,all the existing recommendations (initial report from 2003) are still valid. However three modifications have been proposed by the working group: 1) increased level of evidence concerning the use of PET-scan for suspicion of local or metastatic recurrence (option, level of evidence: A); 2) a new option for the use of PET-scan for revealed cervix cancer recurrence, especially for the therapeutic decision strategy (level of evidence: B2); and 3) new formulation (less strict) of the recommendation concerning the use of PET-scan in the management of endometrial cancer.

Breast Neoplasms↗
PubMed2005

Description and technical pitfalls of a hepatoma model and of intra-arterial injection of radiolabelled lipiodol in the rat.

Intra-arterial metabolic radiotherapy (using lipiodol labelled with iodine-131 or rhenium-188) is a therapeutic approach that can be used for the treatment of hepatocellular carcinomas (HCC). We propose a detailed description of the tumoral model using the N1-S1 cell line as well as a technique for intra-arterial injection of radiolabelled lipiodol in order to undertake preclinical studies necessary for the evaluation of a new molecule. We also report the principal technical pitfalls that were faced. The speed of injection of the tumoral cells is a key factor in the tumoral induction since slow injections lead to a tumoral induction rate of 36.3% compared with 76.6% (P<0.01) when using very slow injections. This parameter should thus be controlled carefully during the subcapsular injection of the tumoral cells. In addition, when injecting radiolabelled lipiodol, anaesthesia should not be performed with isoflurane since this leads to a reduction in tumoral uptake. Indeed, we found a 'tumour/healthy liver' uptake ratio of only 2.1+/-0.7 with isoflurane as against 4.4+/-2.6 (P<0.05) when anaesthesia was carried out by intraperitoneal injection of ketamine. Lastly, we show that the tumour size has an influence on the tumoral uptake of radiolabelled lipiodol; therefore, this parameter must also be carefully controlled.

Anesthetics↗
PubMed2003

Development and biodistribution of 188Re-SSS lipiodol following injection into the hepatic artery of healthy pigs.

Although intra-arterial radiotherapy with (131)I-labelled lipiodol is a useful therapeutic approach in the treatment of hepatocellular carcinomas, various disadvantages limit its use. Here we describe the development of (188)Re-SSS lipiodol, as well as its biodistribution in the healthy pig after injection into the hepatic artery. The (188)Re-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with (188)Re, in cold lipiodol. The radiochemical purity (RCP) of the labelling was checked immediately and at 24 and 48 h. The (188)Re-SSS lipiodol was injected into the hepatic artery of six healthy pigs. They were killed 1, 24 and 48 h post injection, for ex vivo counting. An autoradiographic study was performed in three cases. (188)Re-SSS lipiodol was obtained with a yield of 87%+/-9.1%. The immediate RCP was 93%+/-3.4%. This radiolabelling was reproducible and stable at 48 h in plasma: 90.6%+/-1.5% of the activity remained in the lipiodol with an RCP of 91%+/-4%. Ex vivo counting confirmed the predominantly hepatic uptake and revealed weak lung and intestinal uptake. There was very weak urinary elimination (2.3%+/-0.5% at 48 h) and a slightly higher level of intestinal elimination (4.8%+/-1.9% at 48 h). The autoradiographic studies showed (188)Re-SSS lipiodol to be located mainly in sinusoids, like (131)I-lipiodol. By using the method described here, (188)Re-SSS lipiodol can be obtained with a very high yield and a satisfactory RCP. Its biodistribution in the healthy pig is in agreement with data published elsewhere concerning other types of radiolabelling used for lipiodol, except for the very weak urinary and intestinal elimination, which probably indicates better stability of (188)Re-SSS labelling.

Animals↗
PubMed2003

Safe radiation exposure of medical personnel by using simple methods of radioprotection while administering 131I-lipiodol therapy for hepatocellular carcinoma.

The intra-arterial administration of 131I-lipiodol is a therapeutic approach increasingly used for the treatment of inoperable hepatocellular carcinomas. This technique has even become the reference treatment for hepatocellular carcinomas with portal thrombosis and is the only effective treatment to reduce the risk of recurrence among patients who could benefit from surgical operation. Currently, few data have been published concerning the levels of exposure for personnel carrying out this type of treatment. We undertook a dosimetric study targeted mainly on the exposure of the person performing the injection of 131I-lipiodol to show that this treatment can be carried out with an exposure at the extremities distinctly lower than the regulatory annual threshold by using simple means of radioprotection. The point of puncture was carried out at the level of left femoral artery, the preparation and injection of the therapeutic dose was carried out extemporaneously by the nuclear medicine specialist using a 10 ml syringe (for an injected volume of 4 ml) fitted with an adapted syringe protector. The injection was carried out as rapidly as possible under scopic control while avoiding reflux, with compression carried out by the radiologist. This study comprises 52 intra-arterial injections of 131I-lipiodol (2016+/-92 MBq). For the nuclear medicine specialists, 52 measurements were carried out at the level of the thorax and 41 on the fingers. For the radiologists, 22 measurements were carried out at the level of the thorax and six on their index fingers; nine measurements were carried out at the level of the thorax for the technologist and four at the level of the thorax for the stretcher bearer. For the nuclear medicine specialists, the average dose received at the level of the fingers varies between 140 and 443 microSv (according to the fingers) and the average dose at the thorax is 17 microSv. For the radiologists, the average dose received is 215 microSv at the level of the fingers and 15 microSv at the thorax. These results show that the administration of high therapeutic activities of 131I-lipiodol can be carried out for the exposed personnel with a dose at the level of the fingers much lower than the European regulatory limit of 500 mSv.

Carcinoma, Hepatocellular↗
PubMed2002

Diagnosis of osteomyelitis in the diabetic foot with a 99mTc-HMPAO leucocyte scintigraphy combined with a 99mTc-MDP bone scintigraphy.

BACKGROUND: The aim of this prospective study was to assess the role of 99mTc-HMPAO leucocyte scintigraphy combined with a 99mTc-MDP bone scintigraphy in the diagnosis of the diabetic foot infection (HMPAO-Leu/MDP). METHODS: 75 diabetic patients with suspected osteomyelitis were included. The HMPAO-Leu/MDP scan was considered to be consistent with osteomyelitis when the HMPAO-Leu uptake was concordant in all the incidences with an MDP bone uptake. A HMPAO-Leu uptake without concordant bone MDP activity was considered as a soft-tissue infection. The results of the HMPAO-Leu/MDP scan were compared to the following diagnostic criteria: bone infection was confirmed by radiological follow-up or bone biopsy; the absence of bone infection was confirmed by clinical (healing of the ulcer without antibiotherapy) and radiological follow up. RESULTS: According to these criteria, among the 83 ulcers, bone infection was observed in 41 (49.4%): the HMPAO-Leu/MDP scan was positive in 38 cases, including 14 ulcers with normal or doubtful radiographs at inclusion. In the group of 42 ulcers without proven bone infection, the HMPAO-Leu/MDP scan was negative in 41 cases, including 17 lesions with a soft-tissue infection. CONCLUSION: With a sensitivity of 92.6%, a specificity of 97.6%, the HMPAO-Leu/MDP scan is a reliable tool for the diagnosis of osteomyelitis in the diabetic foot. Neuroarthropathy did not affect the performances of the HMPAO-Leu/MDP scan. Owing to a high spatial resolution this test is very helpful to differentiate bone infection from soft-tissue infection especially in case of neuroarthropathy.

Adult↗
PubMed2001

Two messenger RNAs and five isoforms for Po66-CBP, a galectin-8 homolog in a human lung carcinoma cell line.

Galectins are animal proteins which specifically bind beta-D-galactoside residues and their specific cellular function is not yet clearly established. However, these proteins seem to play a role in neoplastic transformations. Po66 is a murine monoclonal antibody directed against a protein from human lung carcinoma, Po66 Carbohydrate-Binding-Protein (Po66-CBP), which belongs to the galectin-8 family. Our results show that the Po66-CBP gene generates five transcripts by alternative splicing, which could give rise to five proteins: two proteins belong to the tandemly repeated galectin family and three belong to the single carbohydrate recognition domain galectins. All these proteins are encoded by a unique gene located in 1q42. Experiments carried out by reverse transcriptase-polymerase chain reaction show that the levels of expression of these five galectin-8 isoforms are variable during the culture time in SK-MES-1, a human lung squamous carcinoma cell line. Cancer Genome Anatomy Project database analysis confirms the presence of Po66-CBP in lung cancer and its absence in healthy lung.

Amino Acid Sequence↗
PubMed2001

Role of vagal innervation on intragastric distribution and emptying of liquid and semisolid meals in conscious pigs.

The role of vagal innervation on emptying patterns and intragastric distributions of liquid and semisolid meals is still controversial. We aimed to record these features after dorsal, ventral and truncal vagotomies, using external gamma scintigraphy in conscious pigs in which the dorsal vagus specifically innervates the proximal stomach. Imaging of the stomach was performed for all experimental situations and before surgery using 99mTc-labelled glucose and porridge meals. Emptying of liquids was faster after dorsal vagotomy, whereas it was unchanged after ventral and truncal vagotomies (T1/2 = 57 +/- 8.5, 31 +/- 14.4, 54 +/- 9.1 and 42 +/- 14.9 min for intact, dorsal, ventral and truncal vagotomies, respectively). On the other hand, truncal vagotomy significantly reduced the emptying rate of semisolids whereas dorsal and ventral vagotomies had no significant effect (T1/2 = 96 +/- 7.2, 113 +/- 8.1, 75 +/- 9.9 and 260 +/- 56.6 min for intact, dorsal, ventral and truncal vagotomies). Morphological analysis of the gastric shape confirmed an overdistended proximal stomach after truncal vagotomy only. For semisolids, proximal stomach emptying followed the same emptying pattern as the entire stomach, irrespective of the surgical procedure. We concluded that the proximal stomach is the main control for the emptying of liquids and semisolids. The vagal control of overall gastric emptying for semisolids is probably identical to that modulating the intragastric distribution of the meal.

Animals↗
PubMed2001

Changes in intragastric meal distribution are better predictors of gastric emptying rate in conscious pigs than are meal viscosity or dietary fibre concentration.

The effect of dietary fibre on the gastric emptying rate of solids is controversial. Similarly, the mechanisms by which it modulates food intake are partially unknown. Gastric emptying and proximal v. distal stomach filling were evaluated in triplicate on four conscious pigs using scintigraphic imaging. Each animal received in an isoenergetic manner a concentrate low-fibre diet enriched in starch (S) and two high-fibre diets based on sugar beet pulp (BP) or wheat bran (WB). All meals had the same viscosity before ingestion (100.0-100.5 Pa.s). Viscosity of the gastric contents was measured in four additional animals fitted with a gastric cannula. The gastric emptying rate of BP diet was significantly slower than S and WB diets (t1/2 78.4 (sem 5.68), 62.8 (sem 10.01) and 111.6 (sem 10.82) min for S, WB and BP diets respectively, P<0.05). For BP diet only, rate of distal stomach filling was steady during the first 120 min after the meal whereas that of S and WB diets decreased in an exponential manner. Numerous backflow episodes from the distal into the proximal stomach were observed for BP diet that generated the larger intragastric viscosity (0.26 (sem 0.03), 0.3 (sem 0.02) and 0.52 (sem 0.002) Pa.s for S, WB and BP respectively). In conclusion, viscosity of the meal or the percentage total fibre, unlike viscosity of the gastric contents, are poor predictors for emptying. The reduced emptying rate observed with BP is associated with major changes in intragastric distribution of the meal absent with WB and S diets.

Animal Feed↗
PubMed2001

Importance of the choice of the collimator for the detection of small lesions in scintimammography: a phantom study.

99mTc methoxyisobutylisonitrile planar scintimammography (SMM) is mostly performed using low-energy high-resolution (LEHR) parallel collimators. We studied whether using a different collimator could improve the detection of small (< 1.5 cm) lesions for which SMM sensitivity is poor. Thirty four breast phantom configurations were considered, either with hot spheres simulating lesions or without any spheres. For each configuration, four planar acquisitions were performed using LEHR, low-energy ultra high-resolution (LEUHR), high-resolution fan-beam (HRFB) and ultra high-resolution fan-beam (UHRFB) collimators. Images corresponding to the 20% and 10% energy windows and to the Jaszczak subtraction were calculated. A database including 156 borderline images was derived. After training, 10 observers scored the images for the presence of a sphere. The performances in sphere detection were studied using receiver operating characteristic (ROC) analysis. For all types of image, the area under the ROC curve was highest with the UHRFB collimator and lowest with either the LEUHR or the HRFB collimator. For the 10% energy window images conventionally used in SMM, the detection sensitivities averaged 91%, 73%, 60% and 55% for the UHRFB, LEHR, HRFB and LEUHR collimators respectively, for the same specificity of 64%. We conclude that detection of small tumours in planar SMM might be significantly improved by using a UHRFB collimator instead of an LEHR collimator.

Breast Neoplasms↗
PubMed2001

Scintimammography: better detection of small-sized lesions with tomoscintigraphic than planar images, a phantom study.

Planar (99)Tc(m)-methoxyisobutylisonitrile ((99)Tc(m)-MIBI) scintimammography has been used for several years to detect breast cancer tumours, but with low sensitivity for small lesions. Results of tomoscintimammography studies have not been conclusive. We conducted a phantom study to compare the detection of small-sized tumours with planar versus tomoscintigraphic images. We used a data spectrum anthropomorphic fillable breast phantom with two 9.8 mm and 12.4 mm spheres superficially or deep in the breast compartment with sphere/breast activity ratios varying from 3 to 6. We acquired planar and 180 degrees tomoscintigraphic images in each configuration using a double head standard gamma camera. In certain cases we varied different parameters (64x64 matrix or 360 degrees rotation) in a second series of tomoscintigraphic acquisitions. We simultaneously used filtered back-projection reconstruction (FBP) and iterative reconstruction (IR). Planar images were shown by the sphere in 10 out of 25 cases. Tomoscintigraphic images were shown by the sphere in nine out of 25 cases with FBP and in 18 out of 25 with IR. There was a significant difference between IR and FBP (P<0.01) and between planar and IR images (P<0.01), but no significant difference between planar and IR images. The noise/signal ratio was lower with planar images than with the two types of reconstruction (P<0.05) but was not significantly different between the two types of reconstruction. Contrast was lower on planar images than on the two types of reconstruction (P<0.05) and was also better on IR than on FBP images (P<0.05). Granularity was lower for planar images than for reconstruction images (P<0.01) and also lower for IR than for FBP (P<0.01). The tomoscintigraphic reconstructions acquired with a 64x64 matrix were only positive in four out of 10 cases, while they were positive in nine out of 10 with a 128x128 matrix. We concluded that, in this phantom study, tomoscintimammography with IR provides a significant improvement in the detection of small-sized breast tumours compared with planar images. In addition, for tomoscintigraphic images, a 128x128 matrix is preferable to a 64x64 matrix. Those results have, of course, to be confirmed in vivo in a large population of patients with small-sized breast lesions.

Breast↗
PubMed2001

Galectin-8: a complex sub-family of galectins (Review).

Galectins are animal lectins, that can specifically bind beta-galactosides. Twelve galectins have been described in vertebrates, belonging to three different groups: prototype, tandem-repeat and chimeric. These proteins seem to be involved in cellular interactions and neoplastic transformations. We present an overview of a particular galectin member: galectin-8. This galectin, which has been intensively studied over the last six years, presents a particular type of gene regulation. It is widely expressed in tumoral tissues and seems to be involved in integrin-like cell interactions. Studies show that the LGALS8 gene encodes for almost seven mRNAs by alternative splicing pathways and various polyadenylation sites. These mRNAs could encode for six isoforms of galectin-8, of which three belong to the tandem-repeat galectin group (with two carbohydrate binding domains) and the three others to the prototype group (one carbohydrate binding domain). All these isoforms seem to be differentially expressed in various tumoral cells. This untypical galectin-8 subfamily seems to have a complex expression regulation, that could be involved in cancer phenomena.

Alternative Splicing↗
PubMed2000

Somatostatin receptor in breast cancer and axillary nodes: study with scintigraphy, histopathology and receptor autoradiography.

UNLABELLED: We conducted a prospective analysis of somatostatin receptor scintigraphy using (111)In radiolabeled pentetreotide, a somatostatin analog, in patients with breast cancer in the aim to visualize the primary tumor and axillary or parasternal metastatic extension because some malignant breast tumors express somatostatin receptors (SS-R) in 50%, approximately. An analysis of SS-R was performed by autoradiography. PATIENTS AND METHODS: Thirteen patients with clinically suspected breast tumors (T1, T2), and at least one palpable axillary node (N1) were included. In vivo planar scintigrams were acquired 1, 4, and 24 h after subcutaneous, then after intravenous injections (24 h delay between injections). Improved (111)In-pentetreotide uptake in invaded nodes after subcutaneous injection was hypothesized. Ex vivo scintigrams of surgical specimens were also acquired immediately after tumor resection and axillary dissection. Pathological examination and receptor autoradiography were performed on all surgical specimens. RESULTS: Among 11 pathologically proven malignant tumors (9 ductal and 2 lobular carcinomas), only four were scintigraphically visible although six expressed SS-R receptors in vitro. Among six pathologically proven malignant nodes, four expressed SS-R, including two visualized scintigraphically. Scintigrams acquired after subcutaneous injections were less sensitive than after intravenous injections. There were no false positive. False negatives occurred in cases with small tumors with low-density or heterogeneously distributed SS-R. There was no significant difference by histological type or prognostic factors. CONCLUSION: Somatostatin receptor scintigraphy does not appear to be sensitive enough to evaluate axillary node extension of breast cancer or even to confirm the presence of tumoral tissue, and this whatever the administration route for (111)In-pentetreotide.

Adult↗
PubMed2000

Imaging radiation induced muscular necrosis with antimyosin-scintigraphy and computed tomography.

Radiations accidents involving high exposures require accurate assessment of radiation dose for correct surgical or medical management. Techniques involving computed tomography and antimyosin-antibody scintigraphy were evaluated in an experimental model of acute localized irradiation overexposure to 192Ir. Ten rabbits were exposed to a single dose of 192Ir gamma irradiation (120 Gy) on the back (right iliospinal muscle). Computed tomography and antimyosin-antibody scintigraphy results were compared with those in four control animals. Planar scintiscans (posterior views) were performed 48 h post-injection of antimyosin-antibody each week for 2 mo after exposure. An antimyosin uptake was observed in irradiated muscle five weeks after exposure and correlated with computed tomography and histopathology results, showing muscle necrosis. Biodistribution assessed at 7 and 9 wk post exposure confirmed antimyosin-antibody accumulation in damaged muscle. A semi-quantitative analysis of a region of interest over the uptake area in the irradiated muscle (on the right side) and a contralateral non-irradiated region of interest used as control showed that uptake was significantly higher in irradiated animals than in control animals (p < 0.02). Antimyosin-antibody scintiscans used in nuclear cardiology to explore ischemic heart disease, myocarditis or heart transplant rejection could be realized to assess the extent of muscle necrosis after trauma or radiation induced injury.

Animals↗
PubMed2000

Contribution of 99Tcm-DMSA scintigraphy to aetiological diagnosis in renal transplant recipients with impaired renal function.

Routine 99Tcm-dimercaptosuccinic acid (DMSA) scintigraphy was performed in a series of 24 kidney transplant recipients with impaired renal function. Diagnostic findings on planar and tomoscintigraphic acquisitions obtained 3 and 4 h after the injection of 130-140 MBq 99Tcm-DMSA were compared with the diagnosis established by fine-needle biopsy in 13 patients and by clinical course and other examinations (ultrasonography, bacteriology) in 11 patients. Renal scintigraphy demonstrated segmental defects in patients with rejection (n = 2/6), immunosuppressor nephrotoxicity (n = 2/6), acute pyelonephritis (n = 3/3), renal artery stenosis (n = 1/1) and obstructive lymphocele (n = 1/1). Diffuse lack of uptake was observed in one patient with severe renal failure. The scintigram was normal in 14 patients, including three with lesions histologically compatible with graft rejection or immunosuppressor nephrotoxicity. 99Tcm-DMSA was thus found to contribute little to the differential diagnosis between graft rejection and immunosuppressor nephrotoxicity. However, it may be useful for identifying specific disease states, particularly acute pyelonephritis, seen as well-delimited systematized defects. 99Tcm-DMSA scintigraphy could also be used in late follow-up after pyelonephritis in renal transplant recipients.

Adult↗
PubMed2000

Comparison of Tc-99m-labelled antileukocyte fragment Fab' and Tc-99m-HMPAO leukocyte scintigraphy in the diagnosis of bone and joint infections: a prospective study.

Between January and July 1998, we conducted a prospective study to compare Tc-99m-labelled antigranulocyte monoclonal antibody fragment Fab' (LEUKOSCAN) scintigraphy versus Tc-99m-hexamethylpropyleneamine oxime (Tc-99m-HMPAO)-labelled leukocyte scintigraphy (HMPAO-LS) for the diagnosis of unselected patients with bone and joint infection. Twenty-three patients (16 men and 7 women; mean age, 67 years) with suspected bone infection were explored successively with bone scintigraphy, HMPAO-LS and LEUKOSCAN scintigraphy. Thirty-two foci were studied (diabetic foot = 11, prosthetic material = 8, joint disease = 4, others = diagnosed in 18 cases, eight on the basis of bacteriological and histological examination of surgical or puncture specimens, with or without radiographic signs, and 10 on the basis of clinical course and radiographic findings. Overall sensitivity, specificity and accuracy were 86%, 72% and 78%, respectively, for LEUKOSCAN scintigraphy (12 true positives (TP), 13 true negatives (TN), 5 false positives (FP), 2 false negatives (FN)), 93%, 100% and 96%, respectively, for HMPAO-LS (13TP, 18TN, 0FP, 1FN), and 100%, 17% and 53.3%, respectively, for bone scintigraphy. In this small series, LEUKOSCAN scintigraphy was found to be less specific for the diagnosis of osteomyelitis than HMPAO-LS. In addition, the interpretation of LEUKOSCAN scintigraphy is more difficult than HMPAO-LS for the diagnosis of bone infection in the diabetic foot, and would appear to be less discriminating for differentiating soft tissue infection from osteitis in the case of plantar perforating ulcers.

Adult↗