99mTc-HMPAO labelled white blood cell scintigraphy in patients with osteoarticular infection: the value of late images for diagnostic accuracy and interobserver reproducibility.

The objectives of this study were to evaluate the diagnostic value of 99mTc-HMPAO labelled white blood cell scintigraphy (WBCS) in patients with suspected osteomyelitis using late images and to study interobserver reproducibility. This study prospectively included 120 patients, and after a follow-up of one year, only 70 patients (n = 49 with implants, n = 21 without implants) were selected. The final diagnosis of infection was based either on microbiological data (n = 54) or follow-up (n = 16). We performed WBCS with 4 h and 24 h scans. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 77%, 72%, 83%, 64%, and 75% at 4 h, and 74%, 87%, 91%, 59%, and 79% at 24 h, respectively. The interobserver reproducibility shows a 63% prevalence of agreement between results (kappa = 0.5) at 4 h and 80% (kappa = 0.74) at 24 h, respectively. WBCS with 24-h images improves specificity and interobserver reproducibility in patients with suspected osteoarticular sepsis.

[I131 in blood samples: management in the laboratory]. / Gestion au laboratoire d'échantillons de sang de patients traités par iode radioactif.

OBJECTIVES: Patients treated by (131)I may require blood sampling in the days following its administration. We investigated the safety of such samples in terms of radioactivity and the possible disturbance of the analyses by these "131I-spiked" samples. METHOD: 1) The radioactivity of blood samples from 131I-treated patients was measured (dose rate, surface activity, total activity) ; 2) The risk for the personnel was subsequently evaluated and ; 3) The interference of this 131I-generated radioactivity on the results of routine automated and IRMA assays was investigated. RESULTS: 1) All RA measures but two were found below the European limits ; 2) Irradiation of personnel was negligible ; 3) The faint radioactivity did not disturb any analyses. CONCLUSION: These data demonstrate the safety that results from the negligible radioactivity in these blood samples.

Effects of S-adenosylmethionine on human articular chondrocyte differentiation. An in vitro study.

The effect of S-adenosyl-L-methionine (SAMe) on human articular osteoarthritic chondrocytes was studied using a thick-layer culture model. Three SAMe concentrations were tested (1, 10, and 100 micrograms/ml). For 10 micrograms/ml, the most efficient dose, a significant rise in the incorporation levels of 35S-sulfate and 3H-serine was observed, as was as an increase in the hexuronic acid content. All the parameters seem to express a more active protein synthesis, particularly for proteoglycans. Under the same conditions, the proliferation rate of chondrocytes does not undergo important variations. These results point to a direct action on the cell metabolism but little is known concerning the mechanism involved.

Lessons from an unpleasant surprise: a biochemical strategy for the diagnosis of pheochromocytoma.

OBJECTIVE: To audit the performances of the analytes used in the diagnosis of pheochromocytoma and to present a graphical guideline to help the diagnosis. DESIGN: A 5 year retrospective study. SETTINGS: Laboratory and departments of a university hospital. PARTICIPANTS: In-patients, suspected of bearing a pheochromocytoma, were investigated for urinary metanephrines and catecholamines (photometric method) and vanillylmandelic acid, fractionated catecholamines and metanephrines [high pressure liquid chromatography (HPLC) coupled to electrochemical detection (ED)] urinary excretion. MAIN OUTCOME: Patients with a pheochromocytoma (24 out of 2003 patients) were diagnosed by the combination of normetanephrine and metanephrine determination. RESULTS: All analytes but dopamine were significantly elevated in patients with a pheochromocytoma. The area under the receiver operating characteristics (ROC) curves were the highest for total metanephrines, normetanephrine and metanephrine determinations. Because of analytical interferences in the metanephrines determination, the normetanephrine and metanephrine performed better. It is noteworthy that all pheochromocytomas had either normetanephrine or metanephrine levels above their respective optimal threshold (sensitivity 100%). The best optimal threshold performance was reached by the mean of three daily samples. Total or fractionated catecholamines or vanillylmandelic acid were less accurate tools. CONCLUSION: Amongst urinary tests, the combined use of HPLC/ED determination of normetanephrine and metanephrine seems the most effective screening strategy for the diagnosis of pheochromocytoma. The older total metanephrine photometric assay is grieved by analytical interferences.

Radionuclide angiographic demonstration of systemic lung arterialization with arteriovenous fistulas.

Radionuclide angiography has diagnosed systemic arterialization of the right lung base in a patient presenting with a basal thoracic bruit. The bruit was due to high flow in the systemic artery and development of arteriovenous fistulas, confirmed by TCT scan and contrast aortography. But the parenchyma of the right lung base appeared normally aerated on the radiographic studies, and Xe-133 ventilation scintigraphy was normal. This case was therefore classified as systemic arterialization of lung without sequestration.

Value of captopril renal scintigraphy in hypertensive patients with renal failure.

UNLABELLED: The aims of this study were to show the value of captopril renal scintigraphy for detecting a renovascular cause in hypertensive patients with renal failure and to assess the ability to predict the beneficial effect of revascularization on renal function. METHODS: Thirty-eight patients with renal failure (mean glomerular filtration rate = 35 mL/min) underwent renal scintigraphy after injection of 99mTc-mercaptoacetyltriglycine. Baseline scintigraphy was performed, and the test was repeated 24 h later after oral administration of 50 mg captopril given 60 min before the test. RESULTS: In 5 of 6 patients with a renovascular cause for renal failure, and 2 of 3 patients with a probable arterial pathology, scintigraphy had a high probability. The result was indeterminate in the other 2 patients. In 5 of 11 patients with negative arteriography and 14 of 18 patients with probable absence of renovascular pathology, we found a low probability of functional renal artery stenosis. Six revascularization procedures were performed and were predictive of a beneficial effect in 5 patients. Time of peak activity was an effective predictor in each case. CONCLUSION: In hypertensive patients with renal failure, captopril renal scintigraphy can detect hemodynamic dysfunction downstream from a renal artery stenosis and can predict the beneficial effect of revascularization in some cases.

Optimization of a new scintillation gas detector used to localize electrons emitted by 99mTc.

UNLABELLED: We have developed a scintillation gas detector to localize electrons emitted by 99mTc. This type of detector allows direct quantification of images and so provides a clear advantage over autoradiographic film. We have optimized the device to give an image spatial resolution that closely approximates that of typical autoradiographic film. To improve this resolution, it was necessary to select only low-energy electrons (2 and 15 keV) and to devise novel detection and localization techniques for the ionizing particles. METHODS: A parallel-plate proportional avalanche chamber is subject to a uniform electrical field and amplifies the number of released electrons through collisions of ionizing particles in the gas mixture. Light emitted by the gas scintillator during the avalanche process is collected by a highly intensified charge coupled device camera. The centroid of each resulting light distribution is calculated, resulting in a quantitative mapping of the sample's activity. Insertion of the sample within the gas volume improves the efficiency and so provides a method that is both very sensitive and linear. RESULTS: We have shown that in a parallel-plate structure, the application of a high electrical field to the surface of the sample and the selection of appropriate light spots, according to their morphology, can overcome localization errors due to the particles' trajectories. We have obtained a resolution of the order of 30 microm, using electrons from 99mTc. CONCLUSION: This detection technique allows considerable improvement in image resolution. This "electron camera" is a serious rival to existing autoradiographic techniques, because it provides certain other advantages, including direct quantification, linearity, high dynamic range and low noise levels. Thus, new perspectives are made available in quantitative double tracer autoradiography, because electrons can be selected for imaging as a function of their energy.

Unsuccessful lung scan due to major right-to-left shunt through a sinus venosus septal defect.

In a patient with a prior history of cerebral abscess and cerebral ischemia, an unsuccessful perfusion lung scan led to a radionuclide angiocardiogram using an arm vein injection. This showed a total right-to-left (R-L) shunt from the superior vena cava (SVC) to the left atrium. Repeat radionuclide study, through a leg vein, demonstrated a moderate R-L shunt and an interpretable lung scan could be obtained. Catheterization and contrast cineangiogram did not provide the exact diagnosis, the preoperative conclusion being anomalous drainage of the SVC into the left atrium, with atrial septal defect (ASD) and partial anomalous pulmonary venous connection to the SVC. The operative diagnosis was high atrial (sinus venosus) septal defect. This example of major but clinically unsuspected R-L shunt emphasizes the value of performing a perfusion lung scan, preferably in conjunction with radionuclide angiocardiography in patients with a prior history of unexplained cerebral abscess or systemic ischemia. Implications of the site of an ASD on quantitation of L-R shunts by radionuclide methods are also discussed.

Intraperitoneal injection of technetium-99m sulfur colloid in visualization of a peritoneo-vaginalis connection.

Ten minutes after an intraperitoneal infusion of Tc-99m sulfur colloid, a gamma camera was used to obtain anterior abdominal views. This visualized a peritoneoscrotal communication in an 80-yr-old patient. He had developed extensive edema of the genitals and lower limbs after about 6 wk of continuous ambulatory peritoneal dialysis. At operation the communication was confirmed and closed. A repeat test verified the success of operation.

Functional upregulation of granulocytes labeled with technetium-99m-HMPAO and indium-111-oxinate.

UNLABELLED: Indium-111-oxinate-labeled granulocytes have been used in vivo for several years for the detection of abscesses. Technetium-99-m-hexamethylpropyleneamine oxime (99mTc-HMPAO) labeling has more recently been described. METHODS: The influence of radiolabeling by both radiotracers on adhesion glycoprotein CD11b quantification was studied in quiescent and formyl-methionylleucylphenylalanine (fMLP)-activated neutrophils (PMN). Adhesion was assessed on human umbilical endothelial cells (HUVEC) as well as the repercussion of the granulocyte labeling on HUVEC viability (neutral red) and metabolic activity (MTT). Chemotaxis of PMN was evaluated by measuring migration under agarose with fMLP as chemoattractant. We also measured phagocytosis and the production of hydrogen peroxide induced by staphylococcus aureus. RESULTS: Whereas whole functional integrity is maintained after labeling, most of the functions (CD11b expression, adhesion, HUVEC metabolic activity) are up-regulated while chemotaxis is decreased in the presence of both radiotracers. Indium-111-oxinate induces larger alterations than 99mTc-HMPAO. CONCLUSION: These data were obtained in normal volunteers. In patients, alterations due to the in vitro labeling procedure, in addition to potential functional alterations caused by the underlying pathology, should be taken into account during image interpretation.

Quantitative analysis of left-ventricular function using gated single photon emission tomography.

We describe a quantitative method that measures segmental motion of the left ventricle, using tomographic slices obtained by gated single photon emission tomography (GSPECT). These slices contain the major axis of the left ventricle and are presumed to show wall motion directed towards a center of contraction. Values of parameters describing segmental wall motion in GSPECT were obtained from 61 patients, who received a left cardiac catheterization 1 hr later. These values were compared with results of similar calculations applied to data from contrast ventriculography. We conclude that GSPECT allows a detailed and quantitative, noninvasive study of wall motion of all left ventricular segments, with high inter- and intraobserver reproducibility.

Optimized radioiodine therapy of Graves' disease: analysis of the delivered dose and of other possible factors affecting outcome.

The best approach to radioiodine dose selection in the treatment of Graves' hyperthyroidism remains highly controversial. The formula to calculate the individual dose of (131)I to be delivered has been used for half a century and takes into account the thyroid mass, the effective half-life and the maximum uptake of (131)I. The objective of the present study was to evaluate the accuracy of this formula by determining the relationship between the administered dose of (131)I calculated to deliver a target dose of 50Gy to the thyroid and the actual exact organ dose. We further analyzed if therapeutic success, defined by euthyroidism following the individually calculated dose, can be predicted by different pretreatment parameters and particularly by organ dose. One hundred patients with a first episode of Graves' disease and who had received optimal thyroid irradiation after precise dosimetry were retrospectively reviewed. The patients were categorized according to their thyroid function (plasma free thyroxine (T(4)) serum concentration) as eu-, hyper- or hypothyroid during and 1 year after treatment. The relationship between the administered dose and organ dose was assessed by simple regression. We compared free T(4), free tri-iodothyronine, thyroid weight, the number of patients with antithyroperoxidase antibodies and TSH receptor autoantibodies, 24h urinary iodine excretion, (131)I uptake, and the exact dose of (131)I delivered to the thyroid as pretreatment variables. Although we found a correlation between administered dose (mCi) and organ dose (Gy) (r=0.3, P=0.003), the mean coefficient of variation for organ dose was 45%. Individualized radioiodine therapy enabled euthyroidism in 26% of patients and failed in 74% of patients (33% had persistent or recurrent hyperthyroidism and 41% permanent hypothyroidism). (131)I uptake was significantly higher in the hyperthyroidism group in comparison with the euthyroid group. However, organ dose and other pretreatment variables did not differ among the three groups. In conclusion, these results confirm the low performance of individual dosimetry using what are established ratios, since the delivered dose to the gland, although correlated to the intended dose, is highly variable. The finding that other usual pretreatment variables are not different between groups, gives little hope for improving the way of calculating the ideal dose of radioiodine. We suggest to those not yet ready to give a standard or an ablative dose for Graves' hyperthyroidism that they abandon this way to calculate the (131)I dose.

Segmented 5 versus nonsegmented flow quantitation: comparison of portal vein flow measurements.

RATIONALE AND OBJECTIVES: Times of acquisition, mean velocities, mean flows, and their respective standard deviations provided by segmented and nonsegmented flow quantifications (FQ) were compared in the main portal veins of ten healthy adults. METHODS: The segmented FQ performed five phase-encoding lines per segment. The authors successively applied the two electrocardiogram-triggered techniques in the same slice perpendicular to the portal flow direction. Their measurements were compared in particular by means of the statistical analysis proposed by Bland and Altman. RESULTS: The segmented 5 FQ reduced the acquisition time by two compared with the nonsegmented FQ. The mean velocity and mean flow values of the two techniques were not significantly different. The standard deviations were similar. CONCLUSIONS: The segmented 5 FQ showed its major advantage in the portal vein: the acquisition time was reduced without any loss of accuracy or any uncertainty enhancement.

In vitro association of type III collagen with elastin and with its solubilized peptides.

Elastin fibres or elastin solubilized peptides associated with type III collagen, under physiological conditions, to form a gel-like substance. The gel cohesion could be markedly improved either by desiccation process (gently air-dried rather than lyophilized) or by addition of adhesive connective proteins such as fibronectin, laminin and type IV collagen. They conferred to the material the composition and the structural appearance of typical basement membrane-like structure. Their properties enable us to investigate the biomaterial in several domains.

Microencapsulation of isolated pituitary cells by polyacrylamide microlatex coagulation on agarose beads.

Microlatex beads of homogenous size were made by polymerization of a mixture of acrylamide/bisacrylamide dispersed in a microemulsion. The microlatex was aggregated by dilution of the microemulsion in acrylamide solutions. The aggregates were then coagulated by polymerization at the interfaces of agarose beads circulating in a capillary tube containing paraffin oil. Biocompatibility was tested on isolated pituitary cells microencapsulated by this procedure.

Control and isotopic quantification of affinity of antithrombin III for heparin-like surfaces.

Heparin-like materials, characterized by a defined superficial density of functional groups which activate antithrombin III (AT III), when in contact with blood specifically inhibit thrombin as soon as it appears. This paper describes an isotopic method to estimate this density and to visualize the distribution of the affinity sites concerned, both directly with AT III labelled with 125Iodine and indirectly with an anti AT III monoclonal antibody labelled with 111Indium.

Noninvasive assessment of pulmonary arterial hypertension by MR phase-mapping method.

We describe a magnetic resonance (MR) imaging method that emphasizes pressure wave velocity to noninvasively assess pulmonary arterial hypertension. Both the blood flow and the corresponding vessel cross-sectional area (CSA) were measured by MR phase mapping in the main pulmonary artery (MPA) in 15 patients. MPA pressures were also measured, in the same patients, by right-side heart catheterization. Two significant relationships were established: 1) between the pressure wave velocity in the MPA and the mean pressure in the MPA (Ppa) writing pressure wave velocity = 9.25 Ppa - 202.51 (r = 0.82) and 2) between the ratio of pressure wave velocity to the systolic blood velocity peak in the MPA (R) and the mean pressure in the MPA writing R = 0.68 Ppa - 4.33 (r = 0.89). Using these relationships, we estimated two pressure values to frame the actual Ppa value in each patient from the present series with a reasonable reliability percentage (87%).

Plasma concentration of neuropeptide Y in patients with adrenal hypertension.

The mechanisms of hypertension during primary hyperaldosteronism and Cushing's syndrome are not completely understood. An enhanced vascular sensitivity to noradrenaline has been described in both situations. Neuropeptide Y (NPY) induces direct vasoconstriction and potentiates the action of noradrenaline. Sodium retention and dexamethasone have been shown to increase circulating NPY levels in animals and the expression of NPY in neuroendocrine cells. In order to determine if NPY could be involved in the enhanced vascular sensitivity to noradrenaline associated with adrenocortical hyperactivity, we measured plasma NPY in patients with Cushing's syndrome (n = 26) and primary hyperaldosteronism (n = 15) and compared it with that of hypertensive patients with pheochromocytomas (n = 13) or essential hypertension (n = 51) and with normotensive controls (n = 47). The concentration of NPY-Like immunoreactivity (NPY-Li) (mean +/- S.E.) in controls was 39.6 +/- 3.0 pg/ml. Elevated concentrations were found in 77% of the samples collected from pheochromocytoma patients (1180.4 +/- 394.0 pg/ml). NPY-Li levels in patients with essential hypertension (35.0 +/- 2.6 pg/ml), primary hyperaldosteronism (31.3 +/- 3.9 pg/ml) and Cushing's syndrome (33.1 +/- 4.8 pg/ml) were not different from that of controls. NPY-Li levels in hypertensive and normotensive patients with Cushing's syndrome were similar (38.5 +/- 7.5 vs 24.2 +/- 3.7 pg/ml). No correlation was found between the NPY-Li level and the mean blood pressure at the time of sampling. Our results suggest that NPY is unlikely to be involved in the pathogenesis of hypertension associated with primary hyperaldosteronism and Cushing's syndrome.

Radioimmunodetection of rat and rabbit cartilage using a monoclonal antibody specific to link proteins.

Biodistribution analysis using [125I]Fab-6F3 specific to link proteins from human articular cartilage performed in rats by autoradiography showed a high concentration of radioactivity in all cartilaginous tissues. Preliminary immunoscintigraphic assays were performed in rabbits. Front and side view images of whole animals exhibited high uptake in cartilage tissue of the knee articulation, in the invertebral disk and the humeral head. This fixation was still detected 24 h post-injection, although high washout of radioactivity was observed.

Experimental evaluation of a collagen-coated vicryl mesh as a dural substitute.

Dural substitutes must provide immediate restitution of a membranous covering for the brain without inducing any adverse reaction in the host or provoking adhesions to underlying nervous tissues. Ideally, the material should disappear completely and be replaced by tissues similar to the dura mater. In this study, parietal dural defects were created in 12 beagle dogs and closed with a vicryl mesh prosthesis made watertight by a film of bovine collagen. Clinical and biological tolerances were satisfactory. There was one case of early local infection. Gross and microscopic examinations performed between 7 days and 9 months after implantation showed degradation of the prosthetic mesh and connective tissue growth into the implant mimicking dura mater as early as 15 days after implantation. There was no attendant inflammatory reaction or cortical adhesions or other adverse reactions. The authors conclude that collagen-embedded vicryl mesh provides satisfactory biological function and compatibility when used as a substitute for dura mater in the dog.