[en] The chloramine-T method for radioiodination of neurotensin for radioimmunoassay was studied. As conventional procedures produced heterogeneous preparations, labelling was performed with a low amount of chloramine-T (1.8 nmol) in the presence of excess of peptide (6 nmol). Purification and complete separation of labelled from unlabelled peptide was obtained by ion-exchange chromatography on SP Sephadex C-25. Four labelled components were identified by isoelectric focusing, enzymatic cleavage and studies of immunoreactivity. The two components representing monoiodinated preparations labelled at Tyr 3 or Tyr 11 could be isolated. Depending on the binding site of the particular antiserum the appropriate tracer could be selected for use in the radioimmunoassay. The specific radioactivities were high (2303 (2137-2407) μCi/nmol and 1927 (1608-2307) μCi/nmol (median and range)) and the stability of the label and the reproducibility of the procedure was good. (author)

[en] A sensitive and specific radioimmunoassay for the recently isolated neuropeptide with N-terminal histidine and C-terminal isoleucine amide (PHI) has been developed which can detect 3.0 pmol/l of the peptide in plasma. Labelling of PHI with ¹²⁵I was performed by the chloramine T method. Non-specific interference in the assay was excluded by extraction of plasma with ethanol to a mean recovery of 82.4%. Plasma samples diluted parallel to the standard curve. The intra-assay and inter-assay coefficient of variation (CV) values at a level of 24.0 pmol/l were 6.3% and 13.1%, respectively. In 75 normal adults, the fasting PHI concentration ranged from 3.5-30.0 pmol/l with a mean of 14.2 pmol/l. In 235 children, the PHI concentration varied with age. Ingestion of a meal caused a rapid and short-lived increase in the PHI concentration. (Auth.)

[en] The diagnostic value of ultrasonography und percutaneous cholangiography was compared in 114 consecutive patients with obstructive jaundice. The final diagnosis was obtained by surgery or autopsy. Transhepatic cholangiography diagnosed obstruction and its level in all patients, whereas ultrasonography failed to find obstruction in 3 patients and was unable to determine the level in 11 patients. The cause of obstruction was correctly assessed in 106 patients by transhepatic cholangiography and in 74 by ultrasonography. In 15 patients with obstruction caused by common duct calculi ultrasonography only diagnosed the five, and in 9 patients malignant obstruction was diagnosed as calculi. Ultrasonography is a reliable tool for diagnosis of obstructive jaundice and in most cases for localisation of the level of the obstruction. However, diagnosis of the cause of obstruction and of its precise topography requires direct cholangiography. (orig.)

[en] Sixtyfour jaundiced patients were randomly allocated to have fine needle PTC performed with or without prior ultrasonographical localization of the porta hepatis. The general success rate was 97% and complications occurred in two patients (3%). Ultrasonography prior to PTC did not significantly reduce the number of needle passes in the liver parenchyma, the failure rate or the number of complications. Ultrasonic scanning, however, should precede PTC to disclose patients with obstructive jaundice and reveal hepatic and perihepatic abnormalities. (orig.)

[en] We examined the reproducibility of lung nodule volumetry software that offers three different volumetry algorithms. In a lung cancer screening trial, 188 baseline nodules >5 mm were identified. Including follow-ups, these nodules formed a study-set of 545 nodules. Nodules were independently double read by two readers using commercially available volumetry software. The software offers readers three different analysing algorithms. We compared the inter-observer variability of nodule volumetry when the readers used the same and different algorithms. Both readers were able to correctly segment and measure 72% of nodules. In 80% of these cases, the readers chose the same algorithm. When readers used the same algorithm, exactly the same volume was measured in 50% of readings and a difference of >25% was observed in 4%. When the readers used different algorithms, 83% of measurements showed a difference of >25%. Modern volumetric software failed to correctly segment a high number of screen detected nodules. While choosing a different algorithm can yield better segmentation of a lung nodule, reproducibility of volumetric measurements deteriorates substantially when different algorithms were used. It is crucial even in the same software package to choose identical parameters for follow-up. (orig.)