Search

fluoroscopic equipment. There are several limitations to the intracardiac 24 mensional ultrasound catheter system used in the present study. First, in the absence of 3-dimensional capability, the entire transseptal catheter/needle profile cannot be visualized. Therefore, manipulation of the catheter/needle and the transseptal puncture must still be done under fluoroscopic view. Second, the 10 MHz transducer has a limited depth penetration. Thus, the entire interatrial septum may not be visualized in some patients (Figure 1B). However, the ultrasound system provides adequate imaging of needle/catheter contact point at the septum. Therefore, puncture of unwanted structures can be avoided. Finally, the present over-the-wire ultrasound catheter has,a large ‘1OFr profile. With technical advancements and refinements, some of the limitations may be overcome in the future. For example, it may be possible to develop a lower frequency (e.g., 7.5 MHz) transducer catheter for better depth penetration and to reduce the ultrasound catheter profile by eliminating the over-the-wire design. In conclusion, our study indicates that intracardiac echocardiography facilitates safe transseptal catheterization by supplementing a single frontal fluoroscopy.

Seven human ocular melanoma cell lines were established in vitro and 3 of these, GU-4, LLN-40 and its subline C17-11, were characterized. Mice were immunized with these ocular melanoma cell lines, and 2 hybridomas producing monoclonal IgG1antibodies (MAb) were produced. MAb 2/10SN recognizes a 44-kDa monomeric protein, whereas MAb 10/12SN reacts with an 83/65-kDa heterodimeric protein. These melanoma-associated antigens (MAA) are detected at high concentrations in the cytoplasm of ocular melanoma cells. However, cell-surface labelling techniques suggest that these MAA are also associated with the cell-surface membrane. These 2 ocular MAA are also expressed by several skin melanoma cell lines. Immunohistochemical studies have localized these antigens to ocular and skin melanomas, to sweat ducts and basal squamous cells in normal skin, with limited expression in several other normal tissues and some carcinomas. Biodistribution studies in nude mice with human ocular melanomas have demonstrated good localization of 125I-labeled MAb 2/10SN at the tumor sites. Therefore, these 2 MAbs, 2/10SN and 10/12SN, recognize MAA which appear to be unique and may prove useful for imaging purposes. © 1992 Wifey-Liss, Inc.

The phase noise performance of two different microwave analog frequency dividers is characterized and compared with the values obtained using simple theories of noise in injection-locked systems. The direct measurement of the divider noise with a low phase noise synthesizer is not accurate enough, and the residual noise technique is used. The noise levels observed using this technique, between -120 and -155 dBc/Hz at a 10 kHz offset frequency, demonstrate that this divider noise is much lower than the phase noise of most microwave free running oscillators, even if this noise is still high with respect to the residual noise of amplifiers realized with the same active devices. The down conversion of microwave sources up to 40 GHz, is proposed as an application example.

A new analog frequency divider configuration using a resistive field-effect transistor (FET) mixer with a series feedback is proposed. With this configuration, a large synchronization bandwidth of almost 30% has been achieved using an original CAD technique. This bandwidth has been effectively measured on a Ku-band monolithic microwave integrated circuit (MMIC) circuit together with an ultra-low power consumption. Moreover, the processed circuit using a standard 0.2-/spl mu/m PHEMT technology (Philips-PML) is very compact (1.5 mm/sup 2/).

** In order to go further in the path to a space level compliant fully integrated Local Oscillator (LO), this study proposes a solution to the integration of one of the key circuits of the nowadays best performing Phase Locked Loop (PLL) topology : the Sampling Phase Detectors (SPD). After introducing Phase Locked Loop mostly used topologies, the authors focus on phase transfer functions in order to enlighten Sampling Phase Detector advantage over Phase Frequency Comparator as for low phase noise applications. Then Sampling Phase Detector general mode of operation is described to clearly state what must be taken into account to ensure its good performance. The usual hybrid topology is presented and its unapplicability to straight forward integration is discussed. Thus a new Sampling Phase Detector MMIC topology is introduced and its measured characteristics are presented. Eventually, new developments are discussed and results are commented to verify their compliance to expectation.

A new sampling phase detector monolithic microwave integrated circuit (MMIC) using a standard 0.18-/spl mu/m GaAs technology has been designed and tested. The authors emphasize that commutation time has to be taken into account rather than pulse duration, as done in previous presented works. Thus, the new SPD design concept eases command-signal generation. It also solves the tradeoff between phase detection and RF signal input-to-output isolation through the use of a double sampler topology and a proper command-signal generation. It has been designed taking care of space level specifications and environment. Phase detection level above 2 V/sub pp/ and operating frequencies up to 20 GHz have been measured, although higher frequency operation can be expected.

The phase noise performance of two different microwave analog frequency dividers is characterized and compared to the values obtained using simple theories of noise in injection locked systems. The direct measurement of the dividers noise with a low phase noise synthesizer being not enough accurate, the residual noise technique is used. The noise levels observed by this technique, between -120 dBc/Hz and -155 dBc/Hz at 10 kHz offset frequency, demonstrate that this dividers noise is much lower than the phase noise of most microwave free running oscillators, even if this noise is still high with respect to the residual noise of amplifiers realized with the same active devices. An application is proposed to the down conversion of microwave sources up to 40 GHz.

Conflicting data have been reported on the incidence of myocardial abnormalities after mediastinal irradiation for Hodgkin's disease. We studied myocardial perfusion in 31 clinically asymptomatic patients (13 male, 18 female, mean age 35 years) 7 years (range 3-11 years) after mantle field radiotherapy. Thallium-201 tomoscintigraphic data were obtained after exercise, 4 h later and at rest (8-15 days later). Images were analysed visually and quantitatively (sectorial quantification of 201Tl uptake on the bull's eye images of the short-axis slices) compared with those of 35 subjects with a low likelihood of coronary artery disease. Twenty-five tomographic data sets were available. Images were visually abnormal in 21 patients (84%) showing an heterogeneous 201Tl uptake. In 68%, the sectorial 201Tl uptake was lower than the mean 201Tl uptake value minus 2 standard deviations measured in subjects with a low likelihood of coronary artery disease. Significant redistribution (quantitatively assessedor = 10%) was present in 10 patients (40%). In most of the patients, the location and the shape of the defect(s) could not be anatomically related to an epicardial coronary vessel disease. These results indicate that after mediastinal irradiation the 201Tl myocardial uptake is frequently abnormal. The observed patterns suggest a disease of the small coronary vessels and/or the existence of a myocardial fibrosis rather than epicardial coronary artery disease.

OBJECTIVE: To evaluate the value of biliary carcino-embryonic antigen (CEA) in the differential diagnosis of malignant and benign hepatopancreatobiliary disease. PATIENTS: One hundred patients were prospectively studied. Benign diseases were present in 39% of the patients while 61% had malignant diseases. METHODS: Samples of serum were taken from all patients just before endoscopic retrograde cholangiopancreatography (ERCP) and samples of biliary CEA were obtained during ERCP. RESULTS: The sensitivity of serum CEA and carbohydrate antigen 19-9 (CA 19-9) in detecting malignancy were 50% and 92%, respectively, while the respective specificities were 95% and 72%. The mean biliary CEA level of the benign group was significantly different from that of the malignant group (35.7 +/- 8.7 ng/ml vs 268 +/- 85.5 ng/ml), but there was considerable overlap between the two groups. With a cut-off level of 20 ng/ml, the sensitivity and specificity were 84% and 64% respectively. The mean bilirubinaemia value was significantly higher in malignant disease than in benign disease (57.4 +/- 13.9 mumol/l vs 235 +/- 19.8 mumol/l). Multidimensional analysis indicated that only bilirubinaemia (P < 109-3)) was independently predictive of malignant disease. CONCLUSION: Biliary CEA assessment seems useless in distinguished between benign and malignant causes of cholestasis.

In order to detect and quantify intrapulmonary shunts in children with liver disease, a radionuclide method was developed and evaluated in such a population.We studied 135 children in whom the severity of liver disease, in most cases, justified consideration of liver transplantation. Patients were separated into two groups according to their resting PaO2 values under room air: 109 children were normoxic and 26 were hypoxic. A radionuclide scan was performed immediately after intravenous injection of human albumin macroaggregates. Activity of the lungs (L) and brain (B) was counted. A shunt index (SI) was calculated as SI = 100.B/L. We compared this index with blood gases and clinical follow-up.In the normoxic group, SI was 0.43 +/- 0.30 (mean +/- s.d.); none of the 102 children with SI1 developed hypoxemia during their follow-up. Two of the six children with SI1 developed subsequent hypoxemia. In the hypoxic group, the nine children with SI1 did not aggravate their hypoxemia during follow-up. The 17 hypoxic children with SI1 later developed severe hypoxemia.Scintigraphy with intravenous human albumin macroaggregates is more accurate than measuring arterial blood gases to detect IPS in children with cirrhosis.

The aim of this study was to identify malignant thyroid nodules using iodine-123 and thallium-201 simultaneous dynamic acquisition. The image sequences acquired were processed by factor analysis of spectral and dynamic structures (FASDS). Some 49 patients were investigated, and their diagnoses were confirmed by histological examination. Data processing enables the estimation of the spectra of the two isotopes and the evaluation of the kinetics and spatial structures related to each tracer. The superimposition of thallium and iodide sum images allowed us to delineate the nodule accurately. Two groups were defined: 21 patients who had 201T1 uptake in the nodule, and 28 who had none. In the first group, 5 nodules were carcinomas, whereas all nodules in the second group were benign. The results of the 201T1 dynamic study improved the diagnosis of carcinoma as the number of false-positive cases decreased. FASDS succeeds in extracting spectral and kinetic information, proving its usefulness in clinical diagnosis.

Biliary pain without obvious biliary obstruction is common in postcholecystectomy patients. We studied 20 symptomatic patients with episodes of biliary-type pain after cholecystectomy (all having undergone endoscopic retrograde cholangiography), and in 18 asymptomatic postcholecystectomy controls. We performed quantitative hepatobiliary radionuclide analysis with dimethyl-imidodiacetic acid. From a series of 90 dynamic images at 1-min intervals using a gamma camera coupled to a computer, time-activity curves were produced in regions of interest in the liver, intrahepatic biliary tree, common duct, and heart, from which quantitative biliary excretion indexes were obtained. The results demonstrate a biliary kinetic dysfunction in patients with postcholecystectomy pain without morphological abnormalities.

A method is presented for radioimmunological determination of 3alpha, 5beta-tetrahydroaldosterone. It is based upon the reactivity of this steroid with an antiserum induced by the 3-carboxymethyloxime of 18, 21-aldosterone diacetate conjugated with bovine serum albumin. One hundred microliters of urine enzymatically hydrolyzed with an helix pomatia preparation, containing tritiated tetrahydroaldosterone for the yield calculation, were extracted with dichloromethane and chromatographed on a small celite column. The yield after extraction and chromatography was 64 +/- 17%. The radioimmunological determination was carried out in a conventional manner. The method is specific, sensitive (10 pg/tube), exact, reproducible, very simple and extremely rapid. The results showed good agreement with values given by a colorimetric method (p less than 0.001). The median value measured in 45 healthy adult subjects under standard sodium diet was 53.3 microgram/24h (95 % of the population within a 16.6 to 131.1 microgram/24h range). In 78 cases of adrenocortical insufficiency, 60 cases of obesity and 28 cases of hypokalemia, the median values (and the ranges : microgram/24h) were respectively 7.7 (1.0 - 51.0), 80.9 (17.0 - 503.0) and 64.3 (8.0 - 181.0). In 330 hypertensive patients the excretion of tetrahydroaldosterone exceeded the normal range in 115 cases (35%) with a median of 199.7 microgram/24h (131 to 620 microgram/24h).

The performance characteristics of 5 scintillation cameras were compared: Searle 19, Searle 37, Ohio Nuclear, Picker 2C and Toshiba GCA 202. Inherent characteristics including spatial resolution, field uniformity and distortion, energy resolution, count-rate capability and paralyzing time were measured. Extrinsic characteristics such as spatial resolution with emission tests and sensitivity with high resolution, low energy collimators also were measured. The Ohio Nuclear camera gave the best results for most of the parameters studied, followed by Searle 37 PMT, Searle 19 PMT, Picker, and Toshiba. The size of the crystal must also be a criterion for choosing a camera.

Resume Le systeme IMx est un systeme de mesure entierement automatique destine a la realisation des dosages immuno-enzymatiques sur microparticules (MEIA) et de dosages immunologiques par polarisation de fluorescence (FPIA). Grâce a cette combinaison, il permet donc de realiser un nombre relativement eleve de dosages portant sur des substances de poids moleculaires variables. Les performances analytiques du systeme ont ete verifiees dans le cas du dosage de l'alpha-fœtoproteine utilise en cancerologie. Les auteurs font remarquer que l'obtention de bonnes caracteristiques (reproductibilite, seuil minimum de detection, absence de contamination inter-echantillons, reperage d'un effet crochet) passe par un controle de qualite rigoureux au quotidien.

n/a

The circadian (circannual for oxalic acid) variations of 13 urinary variables (volume, creatinine, calcium, oxalic acid, glycolic acid, 17-ketosteroids, 17-hydroxycorticosteroids, phosphates, urea, uric acid, chloride, sodium, and potassium) have been documented in 7 calcium oxalate renal stone formers and 7 healthy men (control group). Urine was collected every 4 h over a period of 24 h. All subjects had the same synchronization: diurnal activity from 07(00) to 23(00) +/- 1 h and nocturnal rest; meals were given at fixed clock hours (08(00), 12(30) and 20(00) +/- 1 h). A statistically-significant rhythm (p less than 0.05) was validated for all variables except urea and calcium in healthy men. In renal stone formers, 6 variables (calcium, oxalic acid, and glycolic acid in particular) had no detectable circadian rhythm. However, a periodicity of c. 8 h (ultradian rhythm) was demonstrated for calcium and oxalic acid with peaks being located around 02(00), 10(00), and 18(00). No circannual variations in oxalic acid output could be observed. The present study shows an alteration of the periodicity of calcium and oxalic metabolisms, i.e. the loss of a circadian (24-h) rhythm and the occurrence of an ultradian rhythm of 8 h. The risk of calcium-oxalate crystallisation appears thus greater at 02(00), 10(00), and 18(00). Furthermore, any study dealing with oxalic acid excretion should state the season of urine collection when comparing renal stone formers and healthy subjects, as significant differences in oxaluria may appear during the summer months and not during the rest of the year.

The conversion of [1,2-3H] corticosterone to 18-hydroxycorticosterone in vitro was studied on human and animal adrenal tissue homogenates. Human adrenals were surgically resected from a patient with Cushing's disease. Sheep adrenal homogenates were prepared from the pooled glands of 20 animals. Incubations supplemented with a NADPH generating system were performed in order to evaluate the effect of aminoglutethimide and its closely related compound glutethimide on corticosterone 18-hydroxylation in vitro. Increasing concentrations of the two drugs were assayed on both human and animal adrenal homogenates. Aminoglutethimide was clearly found to inhibit corticosterone 18-hydroxylation in sheep adrenal homogenates as a 72.6 % inhibition occurred in the presence of only 0.2 μmole of the drug. Inhibition reached 91.1 % in the presence of 0.5 μmole aminoglutethimide. When added to the human incubated adrenal, a 59.4 % inhibition occurred in the presence of 0.5 μmole aminoglutethimide. Glutethimide, a sedative of wide clinical usage, was also found to inhibit corticosterone 18-hydroxylation but the inhibitory effect occurred only in the presence of much higher concentrations. In fact, 5.0 μmoles were necessary to obtain a 43.9% inhibition of 18-hydroxycorticosterone synthesis. This study clearly demonstrates the marked inhibitory effect of aminoglutethimide on corticosterone 18-hydroxylation. Glutethimide, to a lesser extent, also inhibits 18-hydroxycorticosterone synthesis.

The synthesis of aldosterone and 18-hydroxycorticosterone from triated corticosterone by sheep adrenal homogenate have been studied in presence of increasing concentrations of SKF 12185, a product already known as an inhibitor of cortisol synthesis. An approximately 98% inhibition of the synthesis of both steroids occurred with only 2 x 10(-4) M of the drug. In contrast, incubation of a structurally closely related compound (SKF 252 A) under the same experimental conditions resulted in an only 52% inhibition with higher concentrations (2 x 10(-3) M). These findings could explain the marked aldosterone fall that occurs in SKF 12185 treated subjects and supports the therapeutic use of this product in treatment of hyperaldosteronism.

Survival and incidence of hemorrhage and encephalopathy were studied in 121 medically managed cirrhotic patients according to the type of naturally occurring portasystemic shunting. Three types of shunting were distinguishable using scintillation splenoportography, a method whereby morphological and hemodynamic data on portal and hepatic circulation were obtained by external detection. The three patterns were: (1) extrahepatic shunting with partial splenic blood flow diversion, (2) spontaneous total splenic blood flow diversion, and (3) intrahepatic shunting corresponding to portohepatic communications with a diameter larger than 10 mum. The probability of 4-year survival was much lower in case of portasystemic shunting (18%) than in its absence (73%, P less than 0.01). Patients with intrahepatic shunting had a survival rate not significantly different from that of patients with extrahepatic shunting. However, they had the highest incidence of hemorrhage (71%), and hemorrhage was not due to rupture of esophageal varices. The highest incidence of encephalopathy was seen in patients with total splenic blood diversion (40%), but it was not significantly different from that of other cirrhotic patients. No group of patients can be significantly identified as a high-risk group.

One-hundred ten 131I-rose bengal studies (RBI) were performed in infants suspected of having biliary atresia. Fecal RBI excretion of less than 10% was observed in 72 of 73 cases of extrahepatic biliary atresia, but also in 10 of 37 cases of intrahepatic cholestasis of various origins. One-hundred twenty-two RBI tests were performed in children operated on for extrahepatic biliary atresia and 71 tests were performed between postsurgical weeks 3 and 8, and 51 tests were done later. Prognostically, early tests show that fecal RBI excretion of more than 15% was observed in 2 of 34 cases who were later completely jaundice-free and in only 1 of 37 cases where no bile flow restoration occurred.

n/a