Correlation between Long-acting Thyroid Stimulator Protector Level and Thyroid 131I Uptake in Thyrotoxicosis

Out of 50 consecutive untreated patients with diffuse toxic goitre 15 showed long-acting thyroid stimulator (LATS), 30 showed LATS protector only, and five showed neither. LATS protector was present in all the patients with LATS. Infiltrative ophthalmopathy was less common in patients with LATS protector only (40%) than in patients with LATS also (67%), but the difference was not significant. There was a correlation between LATS protector level and thyroid ¹³¹I uptake rate factor (k₁), the coefficient (r) being 0·68 (P < 0·001). LATS level showed no such correlation. The results support the hypothesis that LATS protector is a pathogenic thyroid stimulator in patients with diffuse toxic goitre.     

Iodine131 Uptake in the Gram Staining Technic

The Hucker modification of the Gram staining technic, in which NaI¹³¹ was incorporated with the Gram's iodine solution, was performed as the basic procedure. The Gram positive test-bacteria were Staphylococcus aureus and Bacillus megaterium; the Gram negative were Escherichia coli and Pseudomonas aeruginosa. The uptake of I¹³¹ was measured after the addition of the Gram's iodine solution (NaI¹³¹) to the test-bacteria dried on a glass slide, after the decolorization process and after counterstaining. Radiation was measured by placing the slide under a GM-TGC-2 end-window counting tube after each procedure. The Gram positive test-bacteria retained approximately twice as much I¹³¹ after decolorization and counterstaining as did the Gram negative bacteria. In this, the basic technic, the uptake of I¹³¹ by the test bacteria appeared to be directly related to the crystal violet concentration in the primary staining solution. The uptake of I¹³¹ was not significantly altered by the time of application of the Hucker crystal violet staining solution (15-180 sec), or of the Gram's iodine (NaI¹³¹) solution (30-120 sec) or by the duration of the alcohol decolorization process (30-120 sec).

Variations (herein referred to as variations 2 and 3) of the basic procedure were carried out in which the primary staining solution contained crystal violet combined with NaI¹³¹ or Gram's iodine solution (NaI¹³¹). In variations 4 and 5 the effect of the order of application of the various staining reagents was investigated. In these variations (2-5) all test-bacteria were stained Gram negative. The initial uptake of I¹³¹ was decreased, though in variations 4 and 5 the percent retention of I¹³¹ was increased. In the staining of bacterial spores by different methods (variation 6), it was noted that the initial uptake and percent retention of I¹³¹ was greater than with the vegetative forms. When ovalbumin was stained by the Hucker technic and variations thereof, it was noted that the initial uptake of I¹³¹ was directly related to the protein (ovalbumin) concentration up to an ovalbumin concentration of 1%.     

Prognostic Value of Serum Selenium Levels in Alcoholics

In alcoholics, exposure of Kupffer cells to intestinal-borne Gram-negative bacteria increases free radical release, which may, in turn, enhance cytokine secretion, creating a positive feedback loop, which contributes to liver inflammation. Impaired antioxidant mechanisms further aggravates this scenario. Some trace elements, such as selenium, are main cofactors of antioxidant enzymes. Some authors have found low Se levels in alcoholics in relation either with undernutrition, liver dysfunction, or intensity of alcoholism, but in general, Se supplementation has no effect on survival. In this study we measured serum Se in 16 controls and 76 alcoholics, 34 of them cirrhotics, 68 of whom were followed up for a median period of 38 months; 17 died during this period. Se levels were lower in patients than in controls and were related to prothrombin activity and nutritional status, more closely to this last parameter (stepwise logistic regression analysis). Patients who died showed lower Se values than those who survived. Se values over the median were associated with better survival, assessed by Kaplan–Meier curves and log-rank test. However, in multivariate analysis (Cox regression model), prothrombin activity displaced serum Se as a prognostic factor. We conclude that serum Se levels are low in alcoholics; these low values depend more heavily on impaired nutrition but also on liver dysfunction; although low Se levels were associated with a higher mortality, prothrombin activity displaced serum Se when survival was assessed using Cox’s regression model.     

Myo-Inositol-Dependent Sodium Uptake in Ice Plant

The phytohormone ethylene regulates many aspects of plant growth, development, and environmental responses. Much of the developmental regulation of ethylene responses in tomato (Lycopersicon esculentum) occurs at the level of hormone sensitivity. In an effort to understand the regulation of ethylene responses, we isolated and characterized tomato genes with sequence similarity to the Arabidopsis ETR1 (ethylene response 1) ethylene receptor. Previously, we isolated three genes that exhibit high similarity to ETR1 and to each other. Here we report the isolation of two additional genes, LeETR4 and LeETR5, that are only 42% and 40% identical to ETR1, respectively. Although the amino acids known to be involved in ethylene binding are conserved, LeETR5 lacks the histidine within the kinase domain that is predicted to be phosphorylated. This suggests that histidine kinase activity is not necessary for an ethylene response, because mutated forms of both LeETR4 and LeETR5 confer dominant ethylene insensitivity in transgenic Arabidopsis plants. Expression analysis indicates that LeETR4 accounts for most of the putative ethylene-receptor mRNA present in reproductive tissues, but, like LeETR5, it is less abundant in vegetative tissues. Taken together, ethylene perception in tomato is potentially quite complex, with at least five structurally divergent, putative receptor family members exhibiting significant variation in expression levels throughout development.     

Uptake of 131I-metaiodobenzylguanidine by 6-23 rat medullary thyroid carcinoma

Uptake of 131iodine-metaiodobenzylguanidine (131I-MIBG) by 6-23 rat medullary thyroid carcinoma (MTC), was studied in vitro and in vivo. In vitro, there was an 8-fold increase in 131I uptake by 6-23 cells when labeled with 131I-MIBG (131I 24 +/- 15 cpm/10(6) cells, 131I-MIBG 196 +/- 9 cpm/10(6) cells). MIBG uptake in vitro was the same at 4 degrees C and 37 degrees C. In contrast, 131I-MIBG uptake by PC-12 rat pheochromocytoma cells were 200 times greater (131I-MIBG 42,412 +/- 6,755 cpm/10(6) cells). 131I-MIBG uptake by rat MTC cells in vitro were of a comparable magnitude to the uptake of 131I-MIBG by rat ileal enterochromaffin cells (RIE-1) and mouse colon cancer cells (MC-26). In vivo, uptake of 131I-MIBG by 6-23 MTC tumor was considerably less than in the normal tissues (muscle, liver, spleen, kidney, adrenal and thyroid). Gamma camera studies of 131I-MIBG uptake by 6-23 MTC tumors growing in Wag-Rij rats were only transiently positive in 1 out of 4 rats studied. We conclude that 131I-MIBG is poorly taken up by rat medullary thyroid carcinoma and is an unpredictable marker for localization of rat MTC.     

131I]metaiodobenzylguanidine therapy in paraganglioma.

Our experience with [131I]metaiodobenzylguanidine (131I-MIBG) therapy in a 10 year old boy is reported. At disease onset, in May 1988, this boy presented a large mass in the upper left abdominal quadrant, which was resected with a histopathological diagnosis of extra-adrenal malignant pheochromocytoma (paraganglioma). He subsequently underwent two further surgical resections and chemotherapy. When 131I-MIBG therapy was started, in June 1990, skeletal and abdominal metastases were present. These localizations were revealed by 131I-MIBG scans and confirmed by x-ray examination. At present 6 courses of therapy have been performed with a cumulative activity of 29.6 GBq. Side-effects have been limited to vomiting and mild thrombocytopenia, lasting 2 weeks during the second course of therapy. After 15 months of therapy, a progressive reduction of MIBG uptake, coupled with a stabilization of the lythic lesions, has been observed.     

131I Hippuran Renogram in Acute Renal Failure

A hippuran renogram pattern of the type usually interpreted as indicating urinary tract obstruction was seen in acute tubular necrosis and was present both in the oliguric and in the diuretic phase. It seems that in acute renal failure the renogram does not distinguish urinary tract obstruction from intrinsic renal disease.     

Biases in Multicenter Longitudinal PET Standardized Uptake Value Measurements

This study investigates measurement biases in longitudinal positron-emission tomography/computed tomography (PET/CT) studies that are due to instrumentation variability including human error. Improved estimation of variability between patient scans is of particular importance for assessing response to therapy and multicenter trials. We used National Institute of Standards and Technology-traceable calibration methodology for solid germanium-68/gallium-68 (⁶⁸Ge/⁶⁸Ga) sources used as surrogates for fluorine-18 (¹⁸F) in radionuclide activity calibrators. One cross-calibration kit was constructed for both dose calibrators and PET scanners using the same 9-month half-life batch of ⁶⁸Ge/⁶⁸Ga in epoxy. Repeat measurements occurred in a local network of PET imaging sites to assess standardized uptake value (SUV) errors over time for six dose calibrators from two major manufacturers and for six PET/CT scanners from three major manufacturers. Bias in activity measures by dose calibrators ranged from -50% to 9% and was relatively stable over time except at one site that modified settings between measurements. Bias in activity concentration measures by PET scanners ranged from -27% to 13% with a median of 174 days between the six repeat scans (range, 29 to 226 days). Corresponding errors in SUV measurements ranged from -20% to 47%. SUV biases were not stable over time with longitudinal differences for individual scanners ranging from -11% to 59%. Bias in SUV measurements varied over time and between scanner sites. These results suggest that attention should be paid to PET scanner calibration for longitudinal studies and use of dose calibrator and scanner cross-calibration kits could be helpful for quality assurance and control.     

Measurement of 131 I and 125 I by liquid scintillation counting

When aqueous samples are made miscible with a toluene scintillation solution by means of Bio-Solv BBS-3, high ¹²⁵I and ¹³¹I efficiencies can be achieved over a considerable range of “impurity” quenching, and adequate isotope separations can be achieved using liquid scintillation counters with “linear,” “pseudologarithmic,” or “logarithmic” amplification. Using an example of each sort of counter, we have graphically outlined the two somewhat different procedures for choosing the best instrument settings for single- and double-isotope counting. “Linear” instruments, despite a slightly more complex procedure for selection of settings, may offer the advantage, in double-isotope counting, of somewhat greater isotope separations because of the greater attenuation of photo-electron spectra.