Clinical value of dual-isotope fat absorption test system (FATS) using glycerol [125I]trioleate and glycerol [75Se]triether.

In order to delineate the clinical value of a dual-isotope fat absorption test system (FATS) using glycerol [75Se]triether as lipid-phase marker and glycerol [125I]trioleate as the test lipid, fecal isotope ratios from single stools (and a 72-hr stool homogenate) were compared to quantitative fecal fat excretion. The study included 11 patients without and 24 patients with steatorrhea. With a figure of 0.8% as the upper limit of normal, the test was a reliable indicator of steatorrhea with 87.5% sensitivity and 81.8% specificity; efficiency was 85.7%. Related to a prevalence of steatorrhea of 45.9% as the mean value of 1269 consecutive 72-hr specimens investigated for steatorrhea during 1978-1982, the positive (negative) predictive value of the FATS is 80.3% (87.2%). With 2% as the upper limit of normal, no false positive results ensued. It is concluded that a two-step interpretation of the FATS (0.8% limit and 2% limit) may be regarded a valid qualitative index for steatorrhea. The FATS isotope ratio using single stools correlated well with FATS ratios in the 72-hr stool homogenates (r = 0.97). FATS therefore allows a convenient estimate of steatorrhea from measuring single stools. As a quantitative measure of fecal fat excretion, the FATS is unreliable.

[Iodine excretion and dietary iodine supply in newborn infants in iodine-deficient regions of West Germany]. / Jodausscheidung und alimentäre Jodversorgung bei Neugeborenen in Jodmangelgebieten der Bundesrepublik.

Urinary iodine excretion was measured on the fifth day of life in 461 neonates from nine different towns in the Federal Republic of Germany. There was a progressive fall in levels from north to south, with highest values in Hamburg (2.9 micrograms/dl) and lowest in Freiburg (1.2 micrograms/dl). All levels were lower than those of neonates in other countries in which iodine is added to salt: Stockholm (61 neonates) 9.6 micrograms/dl, Zurich (63) 4.75 micrograms/dl. Iodine analysis of mothers in G ottingen on the fifth day post-partum indicated that iodine excretion in urine of mothers with goitre (51 cases) was significantly lower than in a control group without goitre (38): 17.6 compared with 30.0 micrograms/g creatinine, and the iodine content of breast milk in the goitre group was significantly lower than that of the control group (1.75 compared with 2.5 micrograms/dl). Iodine content in artificial infant milk preparations was of a similar range. These results indicate that iodine supply during the neonatal period in the Federal Republic of Germany is very low; they support the demand for general iodine-salt prophylaxis.

[The prognostic value of the determination of thyroid hormones]. / Der Voraussagewert von Schilddrüsenhormonbestimmungen.

For recognition and exclusion of hyper- and hypothyroidism total thyroxine, index of free thyroxine, free thyroxine and total triiodothyronine were evaluated. Among 532 strictly selected patients, corresponding to the five main thyroid out-patient groups, the four parameters were estimated simultaneously. Their sensitivity and specificity including two combinations of free thyroxine and total triiodothyronine were calculated. On the basis of an average prevalence of the five above-mentioned groups among our patients and the two most frequent interfering factors (administration of oestrogens and additional iodine intake) predictive values were assessed. The following results were obtained. 1. Differences among the various in-vitro parameters are less than generally assumed. For free thyroxine and the combination of increased free thyroxine or total triiodothyronine, sensitivity and specificity were slightly higher than for other parameters. 2. There is insufficiently substantiated probability of positive evidence of hyperthyroid and hypothyroid states being supplied by all the examined parameters if these are the only criteria relied upon. The probability of positive evidence of hyperthyroid states is only acceptable if, prior to use of in-vitro tests, the prevalence has been considerably increased by history and clinical findings. 3. The probability of exclusion of hyperthyroid states supplied by the examined parameters is high. However, despite their high negative predictive value they are insufficient for the definite exclusion of hypothyroid states if the latent types are included.

Incidence of iodine contamination in neonatal transient hyperthyrotropinemia.

Transient hyperthyrotropinemia and/or hypothyroidism have been found in many newborn infants during thyroid screening programs. In Europe the most likely causes are iodine deficiency and iodine overload. Because of the high incidence of transient hyperthyrotropinemia in Berlin we measured iodine concentrations in casual urine samples of newborns with TSH elevations. Urine and blood samples were collected on the 5th day of life. In the prospective study 99 out of 9320 newborns (1.06%) displayed TSH concentrations ranging from 20 to 152 microU/ml. All infants had normal TSH levels during a control examination. The urinary iodine concentrations were significantly elevated in 76 out of the 99 newborns. Most of the patients were born in obstetric departments where iodine-containing antiseptic agents were routinely used for disinfection during labor. The use of iodine-containing antiseptic agents not only results in unnecessary control determinations for the thyroid screening program but also causes an undesirable metabolic situation that may be a potential hazard for the development of the central nervous system.

[Detection of rhinoliquorrhea with 99mTc-labelled human serum albumin]. / Zur Problematik des Nachweises einer Rhinoliquorrhoe mit 99mTc-markiertem Humanserumalbumin.

99mTc-labelled human serum albumin was used in 42 patients, 35 without and 7 with proven rhinoliquorrhoea, to combine liquor scintigraphy with the detection of liquor fistula. Since some 99mTc is split off from albumin during the time of investigation and is actively secreted by mucous membranes and salivary glands it was not possible to detect liquorrhoea by calculation of activity ratios like that of secretion of the nose to blood or saliva. But dividing the activity in the secretion of the nose by that in saliva after 2 and 6 hrs this ratio was independent of the amount of activity and had a sensitivity of 100% and a specificity of 93% in detecting a liquor fistula. Combining scintigrams of the subarachnoidal space with the search for liquorrhoea using an always available radiopharmaceutical such as labelled HSA might be attractive. In 4 of 7 patients with a liquor fistula there was additionally a pathologic result obtained with scintigraphy of the subdural space.

Visualizing cardiac blood pool: comparison of three labeling methods.

The quality of three different labeling methods of visualizing the cardiac blood pool was investigated in 72 patients: 99mtechnetium labeling of red blood cells in vivo or in vitro and human serum albumin. By the simplified technique of in vitro labeling of RBC from the view point of (1) labeling efficiency, (2) activity in the blood, (3) count rates in a standard ROI over the left ventricle and the paracardiac background, (4) ratio of these count rates, and (5) evaluation of image quality, the best results were obtained. HSA and in vivo labeled RBC led to satisfactory results for visual assessment of ventricular performance in most cases. In spite of the slightly higher technical investment involved in the in vitro labeling method this technique appears to be preferable for gated cardiac blood pool studies in view of the excellent labeling quality.

Iodine-induced hypothyroidism and goiter following lipiodolTM lymphography.

Hypothyroid goiter is a rare but well recognized complication following long term administration of iodine containing expectorants and disinfectants in children. Only few reports exist on iodine-induced hypothyroidism after a single injection of the iodized radiopaque dye Lipiodol. A 15-year-old boy with previously normal thyroid function is described who developed hypothyroid goiter within six weeks following bipedal lymphography. Urinary iodine excretion was extremely elevated up to 18 mg/day while serum concentrations of total thyroxine were below the euthyroid range and thyrotropin levels were elevated. After oral L-thyroxine treatment the goiter disappeared. Thyroid function remained normal when treatment was discontinued after five months although iodine excretion was still 50 times higher (2.5 mg/day) than in normal age matched children. The observed alterations of the thyroid gland were caused by a long lasting Wolff-Chaikoff effect with a delayed adaptation to high iodide concentrations.

External radiation exposure of personnel working with 99mTechnetium.

Radiation from 99mTc was measured at typical locations in those areas of a nuclear medicine department where approximately 50 Ci 99mTc is used per year. In addition, measurements of shielded and unshielded syringes containing 99mTc-labelled radiopharmaceuticals were carried out. From these data radiation exposure of hands and of the whole body of personnel was calculated, taking into consideration the mean working times in the areas and the times of direct and indirect handling of 99mTc. They were compared with the mean values obtained by personnel dosimetry through quartz fibre pocket dosimeters and TLD finger ring dosimeters. The whole body radiation calculated from local measurements for technicians (163 +/- 15 mR/year) (mean +/- SE) and for physicians (260 +/- 15 mR/year) was very low judged by the maximum permissible dose of 5,000 mrem/year and correlated well with those of personnel dosimetry (165 +/- 15 R and 265 +/- 15 R/year respectively). Although local radiation was rather high during generator elution and while preparing radiopharmaceuticals (13 +/- 1.2 mR/h) the radiation exposure to the hands of the radiochemists measured by the TLD finger ring dosimeter was low (2.6 +/- 0.2 R/year). This was attained by consistently using long distance tools in order to avoid direct contact with 99mTc-containing vials and syringes. The most critical point of radiation exposure in our investigation were the finger tips during injection of 99mTc, when syringe shielding was not used (80-130 mR/injection of 10 mCi). Under our conditions this amounts to 330-560 R/year when a total of 40 Ci is injected by the same physician. This by far exceeds the maximum permissible dose of 60 rem/year. The dose can be reduced extensively to only 2-3 R/year when tungsten shielding of the syringe is consistently used.

Transient congenital hypothyroidism after amniofetography.

A newborn infant who presented with giotrous congenital hypothyroidism is described. Thyroid dysfunction was due to amniofetography performed 4 days before delivery, during which a total of 5.22 g of iodine as water- and lipid-soluble contrast medium was injected. After oral L-thyroxine treatment hypothyroidism disappeared rapidly. Thyroid function remained normal when treatment was withdrawn after 28 days, underlining the transient character of hypothyroidism.

A radioimmunoassay for 3,5-diiodothyronine.

A radioimmunoassay for the measurement of 3,5-diiodothyronine (3,5-T2) using a 3H-labelled derivative of 3,5-T2 as tracer has been developed. The cross-reactivity of the antiserum was relatively high for T3 (3.1%) and low for T4 (less than 0.0015%). 3,5-T2 serum concentrations measured after fractional enrichment of 3,5-T2 were near or below the detection limit of 0.1 nmol/l in ten normal subjects and 0.38 nmol/l in five hyperthyroid patients. 3,5-T2 was also detected in thyroid tissue. The serum half-time of 3,5-T2 estimated after injection of 2 mg 3,5-T2 in three normal volunteers was 4.5 h.

Radioimmunological measurement of 3,3'-diiodothyronine in serum and amniotic fluid.

A radioimmunoassay for the measurement of 3,3'-diiodo-L-thyronine (rT2) in serum and amniotic fluid is described. Specific antisera to rT2 were produced by immunization of rabbits with rT2 conjugated to bovine serum albumin. The molar cross-reactivity tested for various iodothyronines and iodotyrosines was 0.3% for triiodothyronine and 0.001% for thyroxine. The sensitivity of the assay with a detection limit of 1.8 fmol/tube (0.94 pg/tube) was due to the high avidity of the antiserum and the use of 125I-labelled rT2 of maximum specific radioactivity. In most of 45 normal subjects, serum rT2 levels measured in evaporated ethanol extracts were below the detection limit of 0.018 nmol/1. Mean rT2 concentrations were 0.21 nmol/1 in newborn cord serum and 0.10 nmol/1 in amniotic fluid at 12 to 30 weeks of pregnancy. The molar concentration ratio of 3,3',5'-triiodothyronine (rT3) to rT2 was estimated to be 15.7 in cord serum of newborn. A similar rT3/T2 ratio was found in adults after intravenous application of 500 microgram rT3. Using these data and the known rT3 values, a hypothetical mean serum rT2 concentration in adult normal subjects of 0.015 nmol/1 was calculated. The radioimmunoassay described may be a useful analytical tool in studies of the synthesis as well as the metabolism of thyroid hormones.

[Resorption of fats and carbohydrates following stomach resection and gastrectomy]. / Zur Resorption von Fett und Kohlehydraten nach Magenresektion und Gastrektomie.

125I- and 14C-labelled triolein were used for the examination of fat absorption in patients after gastric surgery. Fat absorption decreased significantly after total and subtotal proximal gastrectomy, but less after distal gastric resection. Carbohydrate absorption, as measured by D-Xylose test, increased in the same manner after both total and partial gastrectomy.

Radioimmunoassay of 3,3',-'-triiodo-L-thyronine (reverse T3) in human serum and its application in different thyroid states.

A radioimmunoassay for the measurement of 3.3',5'-triiodo-L-thyromine (reverse T3, rT3) has been developed. The known limitations of this technique have been overcome by the use of the biologically relevant L-compound for the production of highly specific antisera and for preparing the standard curve. The high sensitivity of the assay (lower limit of detection 20 ng/l serum) was obtained by using 125I-labelled rT3 of maximum specific radioactivity. Mean serum rT3 concentrations for various thyroid states were as follows: Normal subjects: 0.182 mug/l (0,280 nmol/l), hypothyroidism: 0.038 mug/l (0.058 nmol/l), hyperthyroidism: 0.522 mug/l (0.802 nmol/l), pregnants: 0.200 mug/l (0.307 nmol/l), newborn (cord serum): 2.11 mug/l (3.24 nmol/l). The method described should provide additional information with regard to the clarification of thyroxine metabolism.