R. Bares

Metabolic Imaging of Untreated Prostate Cancer by Positron Emission Tomography with sup 18 Fluorine-Labeled Deoxyglucose

PURPOSE We evaluated positron emission tomograph (PET) with 18fluorine (18F)-labeled deoxyglucose for metabolic grading of untreated primary prostate cancer, and differentiation of benign and malignant prostatic disease. MATERIALS AND METHODS A total of 48 patients with untreated prostate cancer of different stages and 16 with histologically confirmed benign prostatic hyperplasia (BPH) underwent static PET after intravenous injection of 150 to 300 MBq. 18F-deoxyglucose. 18F-deoxyglucose accumulation was quantitated by calculating differential uptake ratios and prostate-to-skeletal muscle ratios. RESULTS Low 18F-deoxyglucose uptake was noted in the majority of primary tumors (81%). 18F-deoxyglucose accumulation did not correlate with increasing tumor grade or stage. There was a significant overlap in uptake values in BPH and malignant prostatic disease. A trend towards statistical significance was noted with lower prostate-to-skeletal muscle ratios in patients with BPH (p < 0.07). Increased 18F-deoxyglucose accumulation was detected in some patients with BPH and malignant prostatic disease, as well as in those with lymph node and bone metastases of prostate cancer. CONCLUSIONS 18F-deoxyglucose PET does not allow for metabolic labeling in the majority of untreated primary prostate cancers. BPH and primary prostate cancer cannot be reliably differentiated on the basis of PET. Increased 18F-deoxyglucose accumulation occurs in some primary prostate tumors and in metastatic deposits of prostate cancer.

Pharmacokinetics and pharmacodynamics of cisapride in patients undergoing hemodialysis

Twenty‐two patients who were receiving hemodialysis were studied in three groups of eight subjects each to assess the pharmacokinetics during the dialysis‐free interval and during hemodialysis treatment and to assess the pharmacodynamics of cisapride. Cisapride and its metabolite norcisapride were measured by use of HPLC and gas chromatography, respectively. The pharmacodynamic effect of cisapride was measured by means of radionuclide gastric emptying. After a single oral dose of 20 mg the terminal half‐life of cisapride was 9.6 ± 3.3 hours, the volume of distribution was 4.8 ± 3.3 L/kg, the total oral plasma clearance was 380 ± 161 ml/min, the area under the curve was 1024 ± 447 ng · hr/ml (mean ± SD). Norcisapride only could be detected in the dialysate (0.36 ± 0.067 mg) and was eliminated by a hemodialysis clearance of 34.7 ± 7.9 ml/min. Cisapride reduced gastric retention from 77.6% ± 21.1% to 43.7% ± 18.2% of maximum filling (40 minutes after meals) and normalized the abnormal gastric emptying time in patients receiving dialysis. Cisapride dosage adjustment or substitution after hemodialysis is not necessary.

Effects of intravenous ketamine on gastrointestinal motility in the dog.

ObjectiveThe purpose of this trial was to clarify the effets of intravenous ketamine at anaesthetic and sub-anaesthetic dosages on gastrointestinal motility.Design20 beagles (group 1: 3 mg/ketamine/kg/h,n=10; group 2: 30 mg ketamine/kg/h,n=10), were investigated. Gastric emptying (nuclide gastric emptying studies, liquid and semi-solid test meal), intestinal transit time (Hydrogen breath test with lactulose) and intestinal motor function (perfusion manometry with 8 measuring ports) were determned. As a control condition, the tests were performed on all dogs in the two groups during infusion of physiological saline solution.ResultsNo significant differences in the motility patterns were present between 3 mg ketamine/kg/h and the control condition. For group 2, a moderately significant (p<0.05) increase in the interdigestive motility index was observed for 30 mg k ketamine/kg/h. However, this did not change the transit criteria. There was no significant difference between ketamine and control condition tests with regard to cycle and phase lengths or the propagation rate of the activity front.ConclusionsWe conclude that ketamine provokes no basic changes in gastrointestinal motility, at either sub-anaesthetic doses. It can there-fore be used to advantage in the continuous postoperative analgesia of intensive care patients, where repeated interventions are necessary and no cardiopulmonary contraindications are present.

Prostate-specific antigen as a marker of bone metastasis in patients with prostate cancer

OBJECTIVE Staging in patients with newly diagnosed untreated cancer of the prostate has significant ramifications on the management of the disease. Currently measurement of the serum prostate-specific antigen (PSA) concentration and radionuclide bone scan are two important procedures in the metastatic workup of these patients. We retrospectively evaluated the efficacy of PSA as a staging marker to discriminate prostate cancer patients with bone metastases from those without bone metastases. MATERIALS AND METHODS In a retrospective study 158 prostate cancer patients with (n = 21) and without (n = 137) bone metastases were analyzed. In all patients the initial PSA measurement as well as the radionuclide bone scan were evaluated. RESULTS Patients with bone metastases demonstrated a median serum PSA concentration of 151 ng/ml and only 1 patient revealed a serum PSA concentration of <10 ng/ml. This resulted in a negative predictive value of 98%. In addition 67% of these patients demonstrated a serum PSA concentration of >100 ng/ml, which resulted in a positive predictive value of 74% and an overall accuracy of 92%. CONCLUSION The serum PSA concentration seems to provide useful information with regard to the presence of bone metastasis in patients with newly diagnosed cancer of the prostate. A serum PSA value of <10 ng/ml nearly excludes bone metastases, whereas a serum PSA value of> 100 ng/ml is highly predictive of bone metastases.

The radiation dose to surgical personnel during intraoperative radioimmunoscintimetry

To estimate the radiation exposure to surgical personnel caused by intraoperative radioimmunoscintimetry, we measured dose rates at different distances from patients who had been injected with 950 MBq technetium-99m-labelled intact carcinoembryonic antigen (CEA)-specific antibodies (Szintimun CEA, Behring AG Marburg, FRG) for immunoscintigraphy 24 h earlier. At 0.05 m (corresponding to working positions during surgery) we found 2.0–16.0 μSv h−1 (average 6.4), which is similar to results for nuclear medicine staff. Thus, if radioimmunoscintimetry is to become a routine procedure, according to national regulations in some countries of the European Communities surgical personnel might be regarded as professionally exposed to radiation.

Die radioimmunszintimetrie zur intraoperativen lymphknotendiagnostik beim colorektalen karzinom

In a prospective study 32 patients with primary colorectal carcinomas were studied by means of radioimmunoscintigraphy with the anticarcinoembryonic antigen monoclonal antibody BW 431/26 labelled with either 131I (group 1, n = 17) or 99Tc (group 2, n = 15). Scintigraphy of the resected specimen was used as a model for intraoperative radioimmunoscintimetry, and all positive lymph nodes were marked during the investigation. The results were compared with the data yielded by preoperative investigations (CT, MR, endosonography) and checked by histology and immunohistochemistry. The analysis (sensitivity, specificity) included: type of investigation, time interval from antigen application, type of radionuclide, size of lymph nodes investigated, and serum level of CEA. 131I-Scintigraphy of the resected specimen gave the best results in the detection of lymph node metastases (sensitivity 1, specificity 0.57) and was superior to all other diagnostic procedures. When the investigation was performed 6–8 days after administration of the antibody the specificity improved to 1. The best results (sensitivity 1, specificity 0.91) were achieved in small (< 1 cm) lymph node metastases. A good correlation between scintigraphic diagnosis and immunohistochemical CEA detection was confirmed. Serum levels of CEA had no influence on the scintigraphic results. We conclude that intraoperative radioimmunodetection of lymph node metastases may improve the radicality in the resection of colorectal tumors. The best results are achieved with 131I-labelling and with application of the antibody 6–8 days before the operation.ZusammenfassungIn einer prospektiven Studie wurde bei 32 Patienten mit primären kolorektalen Tumoren eine präoperative Radioimmunszintigraphie mit dam CEA-Antikörper BW 431/26 markiert mit entweder 131J (Gruppe 1, n = 17) oder 99Tc (Gruppe 2, n = 15) durchgeführt. Als Modell für die intraoperative Radioimmunszintimetrie folgte unmittelbar postoperativ eine Präparatszintigraphie mit Markierung aller positiven Lymphknoten. Die Ergebnisse wurden mit den Daten der präoperativen Diagnostik (CT, MR, Endosonographie) verglichen und histologisch Bowie immunhistochemisch kontrolliert. Die Analyse (Sensitivität, Spezifität) erfaßte die Parameter: Untersuchungsart und -zeitpunkt, Radionuklidtyp, Lymphknotengröße and CEA-Serumspiegel. Die Präparatszintigraphie zeigte bei Verwendung des 131J-Antikörpers die besten Ergebnisse in der Lymphknotendiagnostik (Sensitivität: 1, Spezifität: 0,57) und war allen anderen Verfahren überlegen. Die Spezifität konnte bei einer Untersuchung am 6. bis 8. Tag auf 1 angehoben warden. Kleine (< 1 cm) Lymphknotenmetastasen wurden präparatszintigraphisch am exaktesten diagnostiziert (Sensitivität: 1, Spezifität: 0,91). Immunhistochemisch konnte eine gute Korrelation von szintigraphischer Positivität und CEA-Exprimierung nachgewiesen werden, während der Serum- CEA-Spiegel keinen Einfluß auf die Ergebnisse hatte. Wir folgern, daß die intraoperative Radioimmunszintimetrie einen Beitrag zur Verbesserung der Radikalität bei der Resektion kolorektaler Tumoren leisten kann. Die besten Ergebnisse werden mit einer 131J-Markierung und der Applikation des Radionuklid-Antikörper-Komplexes am 6. bis 8. präoperativen Tag erreicht.

Zur Wertigkeit der Positronen-Emissions-Tomographie (PET) mit 18-Fluor Desoxyglucose (18-FDG) zur Differentialdiagnose von Pankreascarcinom/Pankreatitis: Erste klinische Erfahrungen

Bei der Diagnostik von Pankreasprozessen bleibt, obwohl eine Vielzahl neuerer diagnostischer Verfahren (Sonographie/CT/NMR) heute schon fester Bestandteil der klinischen Praxis sind, die Dignitat oft ungeklart. Auch die histopathologische Untersuchung von CT-gesteuerten Feinnadelbiopsien erlaubt oftmals keine zuverlassige praoperative Diagnosesicherung zwischen Pankreascarcinom (PaK) und chronischer Pankreatitis (cPa).

Erhöhte Gallensäurenretention bei biliodigestiven Roux-Y-Anastomosen im Tierexperiment

SummaryIn an experimental study on 65 rats the influence of different Roux-Y biliary anastomoses on the enterohepatic bile acid circulation was investigated. Long (10 cm) and short (3 cm) isoperistaltic and long (10 cm) anisoperistaltic Roux-Y loops were studied and compared to sham-operated controls. 75-SeHCAT a y-labeled synthetic bile acid was used for assessment of enterohepatic circulation. Hepatic excretion and enteric bile flow was investigated by 99m-Tc-HIDA. Intestinal transit time was evaluated by 51-Cr-EDTA an inert marker of intestinal contents. Animals with biliary anastomoses showed an increased retention of the synthetic bile acid 75-SeHCAT compared to the controls. Highest retention values were found in animals with anisoperistaltic loops (t1/2 = 98.6 h). Isoperistaltic loops showed uniform values indenpendently of the length of the Roux-limb (t1/2 = 59.8 h resp. 59.3 h). Differences to the controls (t1/2 = 42.6 h) were highly significant (p<0.001). In the 99m-Tc-HIDA hepatic excretion into the connected small bowel was normal in all groups. But in rats with biliary anastomoses a marked stasis of the 99m-Tc-HIDA in the Roux-Y loop was apparent. Bowel transit time tested by 51-Cr-EDTA showed comparable results in all groups without significant differences. The results demonstrate an increased bile acid retention in Roux-Y biliary anastomoses. An alteration of the enterohepatic circulation due to stasis in the Roux-Y limb seems to be the underlying mechanism.ZusammenfassungIn einer experimentellen Studie an 65 Ratten wurde der Einfluß verschiedener biliodigestiver Roux-Y-Anastomosen auf den enterohepatischen Kreislauf der Gallensäuren untersucht. Es kamen lange (10 cm) and kurze (3 cm) isoperistaltische sowie lange (10 cm) anisoperistaltische Roux-Schlingen zur Anwendung, die Ergebnisse wurden mit den Befunden scheinoperierter Kontrolltiere verglichen. Die synthetische Gallensäure 75-SeHCAT diente zur Beurteilung des enterohepatischen Kreislaufs. Der Gallefluß aus der Leber in den Dünndarm wurde mit dem 99m-Tc-HIDA untersucht. Die intestinale Passagezeit wurde nach oral verabreichtem 51-Cr-EDTA verglichen. Tiere mit einer biliodigestiven Roux-Y-Anastomose zeigten im Vergleich zu den Kontrollen eine erhöhte Retention der synthetischen Gallensäure 75-SeHCAT. Die höchsten Retentionswerte wiesen Tiere mit anisoperistaltischen Schlingen auf (t1/2 = 98,6 h). Bei isoperistaltischen Schlingen zeigten sich uniforme Werte unabhängig von der Schlingenlänge (t1/2 = 59,8 h bzw. 59,3 h). Die Unterschiede zu den Kontrollen (t1/2 = 42,6 h) waren hochsignifikant (p<0,001). Die hepatische 99m-Tc-HIDA Ausscheidung war in allen Gruppen normal, Tiere mit einer biliodigestiven Anastomose zeigten jedoch eine ausgeprägte Stase des 99m-Tc-HIDA in der Roux-Y-Schlinge. Die intestinale Passagezeit zeigte im 51-Cr-EDTA Test vergleichbare Ergebnisse in allen Gruppen ohne signifikante Unterschiede. Die Ergebnisse demonstrieren eine erhöhte Gallensäuren-Retention bei biliodigestiven Roux-Y-Anastomosen. Ursächlich scheint dieser Störung des enterohepatischen Kreislaufs eine Stase in der Roux-Y-Schlinge zugrunde zu liegen.