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1.
Nuklearmedizin ; 44(4): 143-8, 2005.
Article in German | MEDLINE | ID: mdl-16163410

ABSTRACT

AIM: This study was designed to show the effect of a nonionic contrast medium (Iomeprol-300; CM) on the intrathyroidal iodine concentration with and without a concomitant medication with perchlorate (1380 mg/d) to block the thyroidal iodine uptake. VOLUNTEERS AND METHODS: Twelve volunteers recieved 100 ml Iomeprol-300 intravenously and the perchlorate prophylaxis mentioned above. Another 12 volunteers got 100 ml Iomeprol-300 only. By means of X-ray-fluorescence-analysis the intrathyroidal iodine concentration was determined in advance as well as 0.2, 1, 3, 5, 7, 24, 48, 72, and 96 hours after the application of the CM. RESULTS, CONCLUSION: The intrathyroidal iodine concentration did not change in the group of volunteers on perchlorate medication. Without perchlorate the intrathyroidal iodine concentration decreased after the application of the CM when it was initially high (722 +/- 66 microg/ml before, 670 +/- 65 microg/ml after CM; p = 0.046) and increased in case of a low initial concentration (327 +/- 40 microg/ml before, 381 +/- 25 microg/ml after CM; p = 0.046). The effect is significant but its magnitude is too small to be harmful for a patient with a healthy thyroid. The oral application of 1.4 g/d perchlorate inhibits the thyroidal iodine uptake and the intrathyroidal iodine concentration is unaffected by the application of a CM.


Subject(s)
Iodine/metabolism , Iopamidol/analogs & derivatives , Perchlorates/pharmacology , Thyroid Gland/metabolism , Adult , Contrast Media/pharmacology , Female , Humans , Iopamidol/pharmacology , Kinetics , Male , Thyroid Function Tests , Thyroid Gland/anatomy & histology , Thyroid Gland/drug effects
2.
Nuklearmedizin ; 42(3): 109-15, 2003 Jun.
Article in German | MEDLINE | ID: mdl-12802474

ABSTRACT

The version 2 of the guideline for diagnostic standards of thyroid disorders is an update of the guideline published in 1999 and describes standards of in vitro and in vivo procedures. The following statements are modified: In vitro procedures: When measurement of the TSH-receptor antibodies is indicated, the guideline recommends the use of a second generation assay (recombinant human TSH-receptor as antigen). The functional assay sensitivity for the measurement of thyroglobulin should reach a value < or =1 ng/ml. Molecular genetic tests (RET proto-oncogene) are indicated in patients with a newly diagnosed medullary thyroid cancer and in the relatives of patients with hereditary medullary thyroid cancer. In vivo procedures: The sonographic examination should use a probe with a frequency of at least 7.5 MHz. Indications for the thyroid scintigraphy: nodule size > or =1 cm in diameter, autonomous goitre/nodule with clinical or subclinical hyperthyroidism, necessity of a differentiation between Graves' disease and chronic lymphocytic thyroiditis, therapy control after a definitive treatment and - in individual cases - the follow-up of untreated autonomous nodules.


Subject(s)
Thyroid Diseases/diagnosis , Autoantibodies/blood , Humans , Proto-Oncogene Mas , Radionuclide Imaging , Sensitivity and Specificity , Thyroglobulin/analysis , Thyroglobulin/immunology , Thyroid Diseases/diagnostic imaging , Thyrotropin/blood , Ultrasonography
3.
Exp Clin Endocrinol Diabetes ; 109(1): 8-12, 2001.
Article in English | MEDLINE | ID: mdl-11573131

ABSTRACT

Several recently published investigations showed a significant improvement in the iodine supply of the German population, but so far Germany is still considered an iodine deficient country. However most of the studies presented do not meet the epidemiological criteria established by WHO, UNICEF and ICCIDD and may therefore suffer from a selection bias with respect to goiter prevalence estimates. School children, owing to their easy recruitment, representativeness of different socio-economic classes and high vulnerability of Iodine deficiency disorders (IDD), are one of the best target groups for surveillance of IDD. In this field study a total of 591 children were investigated. The total sample included 268 females and 323 males aged 7-17 years. The following data were collected: thyroid size by ultrasound, urinary iodine concentration in a first-morning spot urine, weight, height, sex and age. The median urinary iodine concentration of the children was 183 microg/L. The proportion of samples with concentrations below 100 microg/L or below 50 microg/L was 15.4% and 4.3% respectively. Urine samples with high iodine concentrations were also found amounting to 17.3%. Almost all families (97%) declared to use iodized kitchen salt and 19.6% of all children are taking regularly iodine tablets. Application of the WHO/ICCIDD thyroid volume references to the German children resulted in a goiter prevalence of 0.2%, using either age/sex-specific or body surface area (BSA)/sex-specific cut-off values. Comparison with the P97 values of the original normative data of Gutekunst and Martin-Teichert however gives a goiter prevalence of 3% as expected. The thyroid volumes of the children in our study appear comparable with those reported recently for iodine sufficient children from Switzerland and for iodine replete Berlin children and for children with sufficient iodine supply in the region of Leipzig, so that Germany probably has no longer to be considered an iodine deficient country. Our own study and the most recently published studies on iodine replete children give rise to the supposition that the WHO/ICCIDD recommended thyroid volume references are too high.


Subject(s)
Iodine/deficiency , Iodine/urine , Thyroid Gland/anatomy & histology , Adolescent , Age Factors , Body Height , Body Surface Area , Body Weight , Child , Female , Germany , Humans , Male , Nutritional Status , Organ Size , Population Surveillance , Schools , Sex Factors
4.
Dtsch Med Wochenschr ; 126(9): 227-31, 2001 Mar 02.
Article in German | MEDLINE | ID: mdl-11256036

ABSTRACT

BACKGROUND AND OBJECTIVE: Administration of levothyroxine and/or iodide can effectively reduce the volume of endemic goitre. However, TSH suppression during levothyroxine treatment may increase the number of recurrences through the persistence of intrathyroidal iodine deficiency. With special attention paid to the level of levothyroxine, a comparison was made of two dosages of combined levothyroxine and iodide. PATIENTS AND METHODS: 44 patients with diffuse euthyroid goitre were randomized to two treatment groups. Group A received 100 micrograms levothyroxine + 100 micrograms iodide, group B 75 micrograms levothyroxine + 150 micrograms iodide, all of them for three months. This was followed by three months without the medication. Intrathyroidal iodine concentration was measured at the onset of the study, then three months and six months later. At these same times thyroid volume was measured by ultrasound, as well as urinary iodine and various parameters of thyroid function. RESULTS: Thyroid gland volume was reduced in both groups (group A: -17.3%; group B: -14.8%; p < 0.001). There was no significant difference of intrathyroidal iodine concentration and thyroid volume between both groups. After the treatment period, TSH suppression was more marked in group A, while TSH rise was greater in group B. CONCLUSIONS: Both drug combinations resulted in comparable reduction of thyroid volume, while the intrathyroid concentration of iodine remained unchanged. The smaller rise of TSH after the treatment suggests that the dosage of 75 micrograms levothyroxine + 150 micrograms iodine is to be preferred.


Subject(s)
Goiter, Endemic/drug therapy , Iodides/therapeutic use , Iodine/deficiency , Thyroxine/therapeutic use , Adult , Drug Combinations , Drug Therapy, Combination , Female , Germany , Goiter, Endemic/blood , Goiter, Endemic/diagnostic imaging , Humans , Iodides/administration & dosage , Iodine/analysis , Prospective Studies , Thyroid Gland/diagnostic imaging , Thyroid Gland/drug effects , Thyroid Gland/metabolism , Thyroid Hormones/blood , Thyrotropin/blood , Thyrotropin/drug effects , Thyroxine/administration & dosage , Thyroxine/adverse effects , Ultrasonography
5.
J Endocrinol Invest ; 23(7): 473-5, 2000.
Article in English | MEDLINE | ID: mdl-11005273

ABSTRACT

We present a case of a patient suffering from metastatic differentiated thyroid carcinoma (DTC) and insufficient endogenous TSH production suspicious of secondary hypothyroidism. The use of recombinant human TSH (rhTSH) enabled us to administer a therapeutic activity of radioactive iodine (RAI) under maximal TSH-stimulation, achieving a marked decrease in thyroglobulin accompanied by a clinical improvement.


Subject(s)
Adenocarcinoma, Follicular/complications , Neoplasm Metastasis , Thyroid Neoplasms/complications , Thyrotropin/deficiency , Thyrotropin/therapeutic use , Adenocarcinoma, Follicular/radiotherapy , Adenocarcinoma, Follicular/surgery , Bone Neoplasms/secondary , Humans , Hypothyroidism/drug therapy , Hypothyroidism/etiology , Iodine Radioisotopes/therapeutic use , Male , Middle Aged , Recombinant Proteins/administration & dosage , Recombinant Proteins/therapeutic use , Skull Neoplasms/secondary , Skull Neoplasms/surgery , Thyroid Neoplasms/radiotherapy , Thyroid Neoplasms/surgery , Thyroidectomy , Thyrotropin/administration & dosage
6.
Ophthalmologe ; 97(4): 272-5, 2000 Apr.
Article in German | MEDLINE | ID: mdl-10827463

ABSTRACT

BACKGROUND: An orbital carcinoid metastasis can be specifically imaged by octreotide scintigraphy. Orbital metastases of carcinoid tumors are rare. In the current literature only 27 cases have been published. CASE REPORT: We report on a 59 year-old woman who presented with diplopia 6 years after resection of a carcinoid tumor of the ileum. She also complained about flush and diarrhea. The diplopia was caused by limited extensibility of the right inferior muscle. Computed tomography with contrast revealed an enhancing tumor in the area of the right inferior rectus muscle, which appeared in the MRT as an isointense structure in the T1-weighted image. On staging, we found a contrast-enhancing nodular hepatic lesion. In octreotide scintigraphy, enhancement of the liver, thoracic and abdominal para-aortic lymph nodes and of the right inferior orbit was found. CONCLUSION: The survival times of patients with orbital metastasis of carcinoid tumors range between 7 months and 11 years. No specific treatment is available. Surgical excision is indicated for a symptomatic solitary metastasis. Octreotide is helpful in two ways: (1) as a radiolabeled tracer to detect extra-abdominal and extrahepatic secondary tumors; (2) as a treatment modality for flush and diarrhea, which is successful in over 60% of patients (life expectancy uninfluenced). Our patient is presently being treated with 200 micrograms of octreotide three times a day subcutaneously. Flush episodes and diarrhea have been reduced, but her ophthalmologic symptoms remain unchanged, and she has recently developed cardiac insufficiency.


Subject(s)
Antidiarrheals , Carcinoid Tumor/diagnostic imaging , Carcinoid Tumor/secondary , Ileal Neoplasms , Octreotide , Orbital Neoplasms/diagnostic imaging , Orbital Neoplasms/secondary , Radiopharmaceuticals , Tomography, Emission-Computed, Single-Photon , Antidiarrheals/therapeutic use , Female , Humans , Middle Aged , Octreotide/therapeutic use , Time Factors
7.
Clin Nucl Med ; 24(11): 849-51, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10551465

ABSTRACT

We present a case of increased I-131 uptake in a patient with papillary thyroid carcinoma with local recurrence and distant metastases after a second treatment with retinoic acid as a sign of redifferentiation of the tumor cells. When fine-needle aspiration cytology before and after a second course of retinoic acid treatment were compared, signs of tumor cell redifferentiation were found. This was accompanied by biochemical reexpression of thyroid marker proteins.


Subject(s)
Carcinoma, Papillary/therapy , Iodine Radioisotopes/therapeutic use , Isotretinoin/therapeutic use , Neoplasm Recurrence, Local/therapy , Thyroid Neoplasms/therapy , Carcinoma, Papillary/diagnostic imaging , Carcinoma, Papillary/pathology , Carcinoma, Papillary/secondary , Humans , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/secondary , Lung Neoplasms/therapy , Male , Middle Aged , Neoplasm Recurrence, Local/diagnostic imaging , Neoplasm Recurrence, Local/pathology , Radionuclide Imaging , Thyroid Neoplasms/diagnostic imaging , Thyroid Neoplasms/pathology
9.
Z Geburtshilfe Neonatol ; 203(2): 81-5, 1999.
Article in German | MEDLINE | ID: mdl-10420516

ABSTRACT

UNLABELLED: In this prospective study the longitudinal iodine concentration was compared in breast milk of preterm infants mothers, with and without iodine supplementation. 195 samples of breast milk from 60 mothers were analyzed by HPLC longitudinally. RESULTS: Mothers who take additional iodine (200 micrograms/d) had significant higher mean iodine concentrations in breast milk (mean: 7.6 +/- 6.3 micrograms/dl) than mothers without additional iodine supply (mean: 5.5 +/- 5.8 micrograms/dl/p < 0.02). Nontreated mothers showed significantly more breast milk iodine concentrations below the recommended minimum concentration of 5 micrograms/dl (64%, n = 84) than treated mothers (40%, n = 25/p = 0.0016). Mean iodine intake in preterm infants of treated mothers was higher (11.9 micrograms l/kg) than in preterm infants of nontreated mothers (7.9 micrograms l/kg). DISCUSSION: The measured iodine concentrations in breast milk of preterm infants mothers markedly varied inter- and intraindividual. The variations might be explained by irregular daily iodine intake and a dilution effect by increasing breast milk volumes. CONCLUSIONS: Iodine supplementation of lactating mothers leads to elevated iodine content of their breast milk. The recommended intake of iodine for both newborns (15 micrograms l/kg) and preterm infants (30 micrograms l/kg) was not reached in the breast fed preterm infants in both groups of our study.


Subject(s)
Deficiency Diseases/prevention & control , Dietary Supplements , Infant, Premature , Iodine/administration & dosage , Iodine/deficiency , Milk, Human/chemistry , Postpartum Period/metabolism , Adult , Chromatography, High Pressure Liquid , Deficiency Diseases/epidemiology , Female , Germany/epidemiology , Humans , Infant, Newborn , Nutritional Requirements , Prospective Studies
10.
Exp Clin Endocrinol Diabetes ; 106 Suppl 4: S34-41, 1998.
Article in English | MEDLINE | ID: mdl-9867194

ABSTRACT

The most important information in the determination of the status of iodine nutrition of a population comes from the measurement of the urinary excretion of iodine. Several methods are available for measuring urinary iodine. The choice among methods depends on the intended application, the number of samples, the cost and the technical capability. Epidemiological field studies demand simple, rapid and cost-effective methods. Suitable for these applications are the rapid urinary iodide test and the ammonium persulfate oxidation method which gives comparable results to the chloric acid method without having the drawbacks of being hazardous and explosive. In research studies however, sophisticated automated technology like the Technicon Autoanalyzer or Paired-Ion Reversed Phase HPLC are used in which the high cost of instrumentation are outweighed by the benefits of processing a large number of samples with high accuracy and minimal technician time. For determining serum inorganic iodide (SII) the HPLC assay is the method of choice, because contaminations from the protein bound iodine fraction do not interfere with the detection process. The clinical relevance of the measurement of SII is limited, but allows the calculation of the absolute iodine uptake which has great value in pathophysiologic studies.


Subject(s)
Iodine/blood , Iodine/urine , Thyroid Diseases/blood , Thyroid Diseases/urine , Ammonium Sulfate/chemistry , Chromatography, High Pressure Liquid , Colorimetry , Epidemiologic Methods , Humans , Reagent Kits, Diagnostic
11.
Thyroid ; 8(11): 981-7, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9848710

ABSTRACT

Currently, fine-needle aspiration cytology is a valuable tool in the routine diagnosis of suspicious thyroid nodules. We present a very sensitive method for the molecular analysis of the expression of several genes important for normal thyroid function in parallel to the cytological diagnosis. We adapted reverse transcriptase polymerase chain reaction (RT-PCR) to amplify thyroid-typical mRNAs in samples of thyroid carcinoma cells as small as those obtained by fine-needle aspiration biopsy (FNAB), ie, 100-1000 cells, and applied this procedure to four routinely taken FNABs. Gene products such as thyroglobulin (Tg), thyroid-stimulating hormone-receptor (TSHr), sodium/iodide-symporter (NIS), type I iodothyronine-5'-deiodinase (DI), and type II iodothyronine-5'-deiodinase (DII) were analyzed. To establish RT-PCR protocols, serial dilutions of follicular thyroid carcinoma cells, FTC-133, which express these genes at low levels, were initially used for RNA isolation. Successful RNA isolation and reverse transcription were checked by the amplification of beta-actin mRNA. We detected the mRNAs coding for Tg in as little as 10 cells, for NIS in 100 cells, and for TSHr, DI, and DII in 10,000 cells. After preparing cytological smears of four routinely taken FNABs, all above-mentioned thyroid-typical mRNAs were observed by using the material remaining in the needle for RNA isolation followed by RT-PCR. This method offers the possibility of obtaining two different types of information from the same routinely taken thyroid FNAB: the cytological diagnosis and the expression pattern of several diagnostically relevant genes. Therefore, a more specific diagnosis could be rendered in the preoperative state, and may lead to more specific therapy.


Subject(s)
Biopsy, Needle , Carcinoma/genetics , Genes/physiology , Reverse Transcriptase Polymerase Chain Reaction , Thyroid Gland/physiology , Thyroid Neoplasms/genetics , Carcinoma/pathology , Humans , RNA, Neoplasm/metabolism , Thyroid Gland/pathology , Thyroid Neoplasms/pathology , Thyroid Nodule/genetics , Thyroid Nodule/metabolism , Thyroid Nodule/pathology , Tumor Cells, Cultured
12.
Exp Clin Endocrinol Diabetes ; 106 Suppl 3: S12-6, 1998.
Article in English | MEDLINE | ID: mdl-9865546

ABSTRACT

Assessment of iodine deficiency and monitoring of iodine supplementation programs demands rapid, simple and cost-effective methods for the determination of urinary iodide concentrations. We propose a rapid test based on the iodide-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine by peracetic acid/H2O2 to yield colored products. The color of the chemical reaction is compared with color categories of a pictogram corresponding to three ranges (<10, 10-30, and >>30 microg/100 mL) of iodide concentrations. The test is very easy to perform and does not require any instrumentation or apparatus. Sample preparation is simple and consists in the removal of interfering substances by disposable columns, 65 x 10.5 mm, packed with specifically prepared activated charcoal. For comparison with a reference method for measuring urinary iodide (HPLC), we determined the iodide concentrations of 370 random (untimed) urine samples from consecutive patients by both HPLC and the rapid test. The results obtained by both methods are in close agreement with respect to classification of the samples according to the above three ranges, with a maximum difference of <5% for each range. This rapid test is therefore very well suited to epidemiological surveys of iodine deficiency especially in developing countries.


Subject(s)
Colorimetry/methods , Iodides/urine , Iodine/deficiency , Benzidines , Chromatography, High Pressure Liquid , Chromogenic Compounds , Humans , Hydrogen Peroxide , Indicators and Reagents , Oxidation-Reduction , Peracetic Acid , Spectrophotometry , Time Factors
13.
Exp Clin Endocrinol Diabetes ; 106 Suppl 3: S27-31, 1998.
Article in English | MEDLINE | ID: mdl-9865550

ABSTRACT

This work describes an optimization of a simple photometric determination of iodine concentrations in urine using a modified ceric arsenite method with ammonium persulfate as oxidant. By means of this sensitive method iodine concentrations can be determined in very small specimens (50 microL). Urine samples (105) collected from a mixed population, were analyzed for urine iodine content by the optimized ammonium persulfate method, a Technicon Autoanalyzer II and a paired-ion-RP HPLC. We found that the precision of this optimized ammonium persulfate method yields inter assay CVs of <10% for urinary iodine concentrations >10 microg/dL. Recovery of [123I]iodide added to urine in vitro was 100.9 +/- 2.4%. The detection limit was 0.0029 microg iodine. There was a high correlation between all three methods (r > 0.94 in any case) and the interpretation of the results was consistent. We conclude that this simple, manual ammonium persulfate method is suitable for urinary iodine analysis and can be performed in any routine clinical laboratory.


Subject(s)
Autoanalysis , Chromatography, High Pressure Liquid , Iodine/urine , Spectrophotometry , Ammonium Sulfate , Arsenites , Autoanalysis/instrumentation , Colorimetry , Humans , Iodides , Iodine Radioisotopes , Sensitivity and Specificity
14.
Exp Clin Endocrinol Diabetes ; 106 Suppl 3: S31-3, 1998.
Article in English | MEDLINE | ID: mdl-9865551

ABSTRACT

X-ray fluorescence analysis is based on the principal that the electron structure of stable iodine in the thyroid is excited by Americium-241 gamma rays to emit a characteristic fluorescence radiation which is proportional to the amount of iodine present in the gland. A stationary measuring system consisting of a 11.1 GBq Am-241 source and a high-purity Germanium detector with spectrum analyser has been improved by a PC guided method for sonographic definition of the measuring volume. The lower limit of detectibility of the system corresponds to 0.01 mg of Iodine per ml of thyroid volume; the in vivo precision given as coefficient of variation amounts to 15%. The thyroid is exposed with a radiation dose of 6 microSv per measurement. First studies with this improved system carried out in 50 female volunteers between 20 and 40 years of age with normal thyroid volumes resulted in a mean iodine concentration of the thyroid of 0.665 +/- 0.304 mg/ml. The mean iodine excretion in urine was normal with 10.8 +/- 10.4 microg/dl.


Subject(s)
Iodine/analysis , Spectrometry, X-Ray Emission , Thyroid Gland/chemistry , Adult , Female , Humans , Iodine/urine , Sensitivity and Specificity , Spectrometry, X-Ray Emission/instrumentation
15.
J Neurooncol ; 38(1): 27-40, 1998 May.
Article in English | MEDLINE | ID: mdl-9540055

ABSTRACT

The surgical resection of medulloblastoma (MB), the most frequent malignant brain tumor in children, often remains subtotal. To estimate the response to further treatment the residual tumor is monitored by CT or MRI. The interpretation of both imaging techniques is complicated by disturbances resulting from surgery and radiation. Our study searched for alternative imaging techniques and asked the following questions. 1) Do MB express somatostatin receptors (SSTR), 2) is SSTR scintigraphy a sensitive imaging technique for the follow-up and the detection of vital tumor tissue in children with MB, and 3) do the results of SSTR scintigraphy correlate with the in vitro analysis of MB tissue by SSTR autoradiography. We analyzed the SSTR status in 20 children with MB, aged 1 to 15 years. Sixteen SSTR scintigraphies using Indium-111-DTPA-D-Phel-pentetreotide were performed in 14 children. MB tissue of 14 children was analyzed by SSTR autoradiography using Iodine-125-Tyr3-octreotide. In 8 cases SSTR were measured by both methods in vivo and in vitro. In comparison with conventional imaging, results of SSTR scintigraphy were true positive in 7 of 7 patients, true negative in 9 of 9 patients, including one patient with false positive findings in MRI, false negative in only one patient with small spinal metastases (diameter < 3 mm) and false positive in none of the analyzed patients. In all cases with residual tumor (n = 3) and suspected relapse (n = 4) the diagnosis could be confirmed (n = 4) or excluded (n = 3), consistent with the results of MRI and tumor histology. All MB tissues analyzed by SSTR autoradiography (n = 14) showed an extremely high density of SSTR ranging from 4047 to 15526 dpm/mg MB tissue. MB (n = 8) which were analyzed by SSTR scintigraphy and autoradiography demonstrated consistent results in evaluation by both methods. In cases where the integrity of the blood-brain barrier was tested by Tc-99m-DTPA scintigraphy (n = 10), the SSTR-to-brain scintigraphy index confirmed the tumor specificity of radionuclide uptake. We conclude that 1) MB tissue expresses a particularly high density of SSTR, 2) the high density of SSTR in autoradiography correlates with a sensitive imaging of these tumors by SSTR scintigraphy, 3) SSTR scintigraphy might be a valuable imaging method for detection of vital MB tissue in patients with residual tumor or relapse.


Subject(s)
Brain Neoplasms/diagnostic imaging , Brain Neoplasms/diagnosis , Medulloblastoma/diagnostic imaging , Medulloblastoma/diagnosis , Receptors, Somatostatin/metabolism , Adolescent , Autoradiography , Brain Neoplasms/pathology , Child , Child, Preschool , Female , Humans , Infant , Magnetic Resonance Imaging , Male , Medulloblastoma/pathology , Radionuclide Imaging
16.
J Clin Endocrinol Metab ; 83(3): 1007-12, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9506764

ABSTRACT

Assessment of iodine deficiency and monitoring of iodine supplementation programs demand rapid, simple, and cost-effective methods for the determination of urinary iodide concentrations. We propose a semiquantitative rapid test, based on the iodide-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine by peracetic acid/H2O2, to yield colored products. The color of the chemical reaction is compared with color categories of a pictogram corresponding to three ranges: <100, 100-300, and >300 microg/L (<0.79, 0.79-2.36, and >2.36 micromol/L) of iodide concentrations. The test is very easy to perform and does not require any instrumentation or apparatus. Sample preparation is simple and consists of the removal of interfering substances by disposable columns, 65 x 10.5 mm, packed with purified activated charcoal. For comparison with a reference method for measuring urinary iodide, by high-performance liquid chromatography, we determined the iodide concentrations of 370 random (untimed) urine samples from consecutive patients by both high-performance liquid chromatography and the rapid test. The results obtained by both methods are in close agreement, with respect to classification of the samples according to the above three ranges, with a maximum difference of less than 5% for each range. Median (y) values of a given distribution of urinary iodide concentrations can be calculated from the percent (x) of samples below 100 microg/L (0.79 micromol/L) using the regression equation: y = 179.78 - 1.60x. This rapid test, therefore, is suited to epidemiological surveys of iodine deficiency, especially in developing countries.


Subject(s)
Iodides/urine , Chromatography, High Pressure Liquid , Hot Temperature , Humans , Osmolar Concentration , Reagent Kits, Diagnostic , Spectrophotometry , Time Factors
17.
J Clin Endocrinol Metab ; 81(5): 1780-3, 1996 May.
Article in English | MEDLINE | ID: mdl-8626834

ABSTRACT

It has been suggested that not only the position but also the nature of the mutations of the ret protooncogene strongly correlate with the clinical manifestation of the multiple endocrine neoplasm type 2 (MEN 2) syndrome. In particular, individuals with a Cys634-Arg substitution should have a greater risk of developing parathyroid disease. We, therefore, analyzed 94 unrelated families from Germany with inherited medullary thyroid carcinoma (MTC) for mutation of the ret protooncogene. In all but 1 of 59 families with MEN 2A, germline mutations in the extracellular domain of the ret protein were found. Some 81% of the MEN 2A mutations affected codon 634. Phenotype-genotype correlations suggested that the prevalence of pheochromocytoma and hyperparathyroidism is significantly higher in families with codon 634 mutations, but there was no correlation with the nature of the mutation. In all but 1 of 27 familial MTC (FMTC) families, mutations were detected in 1 of 4 cysteines in the extracellular domain of the ret protooncogene. Half of the FMTC mutations affected codon 634. Mutations outside of codon 634 occurred more often in FMTC families than in MEN 2A families. In all but 1 of 8 MEN 2B patients, de novo mutations in codon 918 were found. These data confirm the preferential localization of MEN 2-associated mutations and the correlation between disease phenotype and the position of the ret mutation, but there was no correlation between the occurrence of hyperparathyroidism or pheochromocytoma and the nature of the mutation.


Subject(s)
Drosophila Proteins , Genotype , Multiple Endocrine Neoplasia/genetics , Mutation , Phenotype , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Amino Acid Sequence , Base Sequence , Carcinoma, Medullary/genetics , Codon , Exons , Germany , Molecular Sequence Data , Multiple Endocrine Neoplasia Type 2a/genetics , Proto-Oncogene Proteins c-ret , Thyroid Neoplasms/genetics
18.
Nuklearmedizin ; 34(1): 20-3, 1995 Feb.
Article in German | MEDLINE | ID: mdl-7724360

ABSTRACT

We studied the effects of radioiodine therapy (RIT) for autonomously functioning thyroid nodules (AFTNs) and Graves' disease on thyroid function and size up to one year after RIT. In 230 patients with AFTNs, a dose of 300 Gy was effective in about 90% of the cases 6 months after RIT. Out of 65 patients suffering from Graves' disease, 5 patients (8%) had persisting hyperthyroidism 6 months after RIT with a dose of 150 Gy. This group consisted exclusively of patients with manifest hyperthyroidism at the time of RIT. As determined by ultrasonography 6 months after RIT, a reduction of thyroid size by about 40% and 60% was observed in patients with AFTNs and Graves' disease, respectively.


Subject(s)
Graves Disease/radiotherapy , Hyperthyroidism/radiotherapy , Iodine Radioisotopes/therapeutic use , Follow-Up Studies , Humans , Hyperthyroidism/physiopathology , Middle Aged , Radiotherapy Dosage , Retrospective Studies , Time Factors
19.
Clin Chem ; 40(6): 908-13, 1994 Jun.
Article in English | MEDLINE | ID: mdl-8087985

ABSTRACT

We propose an automated method for the routine analysis of urinary iodide, using paired-ion reversed-phase HPLC with electrochemical detection and a silver working electrode. Assay conditions include a flow rate of 1.0 mL/min and an operating potential of 0.10 V. The retention time for iodide is 5.4 min. Sample preparation can be semiautomated by use of a reduced-pressure manifold. The detection threshold (signal-to-noise ratio of 3) was 2 pmol, corresponding to 0.04 mumol/L. The within-run precision (CV) for a pooled urine sample was 3.9% at 452 nmol/L iodide. The average recovery of added iodine was 94%. For comparison with a colorimetric method, we measured 177 random (untimed) urine samples by both HPLC (y) and a Technicon AutoAnalyzer acid digestion method (x). After removal of organically bound iodine, the results for unbound urinary iodide determined by the two methods were nearly identical (r = 0.99; y = -0.03 + 1.00x; Sy/x = 0.12 mumol/L). Comparison of total urinary iodine measured by the Technicon AutoAnalyzer with unbound urinary iodide determined by HPLC also showed a high correlation (r = 0.96; y = -0.03 + 0.78x; Sy/x = 0.23 mumol/L), because iodine is excreted in urine mainly as iodide. We conclude that iodine in urine can be accurately determined by the more convenient HPLC assay.


Subject(s)
Chromatography, High Pressure Liquid/methods , Iodides/urine , Autoanalysis , Chromatography, High Pressure Liquid/statistics & numerical data , Colorimetry , Electrochemistry , Electrodes , Humans , Sensitivity and Specificity , Silver , Software
20.
Eur J Endocrinol ; 130(5): 498-501, 1994 May.
Article in English | MEDLINE | ID: mdl-8180679

ABSTRACT

Hyperthyroidism induced by contrast agents in a major problem in patients with pre-existing thyroid disease, particularly in patients with functional thyroid autonomy. The present study was undertaken to evaluate whether contrast media applied during endoscopic retrograde cholangiopancreaticography (ERCP) may result in a significant increase of serum iodine levels and thus may be associated with the risk of iodine-induced hyperthyroidism. The courses of serum concentrations of total iodine and free iodide, as well as of urinary iodine excretion, were measured in 15 patients before and up to 21 days after ERCP. During ERCP, the non-ionic contrast medium iopamidol was instilled in amounts resulting in a total iodine load of 57.4 +/- 22.8 mmol (7.3 +/- 2.9 g). In all patients, ERCP resulted in a highly significant increase in serum levels of total iodine from 0.8 +/- 0.5 to 85.2 +/- 116.9 mumol/l 4 h after application of the contrast agent. In parallel, serum iodide levels were raised from 0.06 +/- 0.04 to 5.42 +/- 6.09 mumol/l and urinary iodine excretion from 71.1 +/- 35.7 mumol/mol creatinine to 621,620.9 +/- 636,492.2 mumol/mol creatinine. Peak concentrations of serum iodine are well related to the total amount of iodine applied (p < 0.05). During follow-up, iodine levels returned to pre-exposure levels within 2-3 weeks. Levels of thyrotropin, free thyroxine, and free triiodothyronine remained unchanged during the follow-up period. In conclusion, endoscopic application of iodinated contrast agents during ERCP leads to significant increases of serum levels of total iodine and free iodide and of urinary iodine excretion.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Cholangiopancreatography, Endoscopic Retrograde , Contrast Media/pharmacokinetics , Hyperthyroidism/chemically induced , Iodine/pharmacokinetics , Absorption , Adult , Aged , Aged, 80 and over , Contrast Media/adverse effects , Female , Follow-Up Studies , Humans , Iodides/blood , Iodides/urine , Iodine/adverse effects , Iodine/blood , Male , Middle Aged , Risk Factors
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