The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Carl Muller - One of the best experts on this subject based on the ideXlab platform.
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a new peroral non radioactive vitamin b12 absorption Test compared with the Schilling Test
European Journal of Haematology, 2009Co-Authors: Erik M Magnus, Carl MullerAbstract:: The results of a non-radioactive, peroral absorption Test have been compared with the results of the traditional Schilling Test in 31 cobalamin-deficient patients. The non-radioactive Test is simple to perform, is less costly than the Schilling Test and seems to give reliable results. The non-radioactive Test should be performed after cobalamin treatment, but not until the plasma cobalamin value has declined to below 450 pmol/l. Normal Schilling Test was noted in one-third of the patients, while normal non-radioactive Test was noted in only one-fifth of the patients. The results reveal some discrepancies between the two Tests regarding the response to intrinsic factor. In the non-radioactive Test without intrinsic factor, the great variation in values may reflect varying secretion of intrinsic factor, possibly secondary to infestation with Helicobacter pylori. "False normal" Schilling Test seems to be more common than previously believed.
Lionel S Zuckier - One of the best experts on this subject based on the ideXlab platform.
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effect of prior radiopharmaceutical administration on Schilling Test performance analysis and recommendations
The Journal of Nuclear Medicine, 1996Co-Authors: Lionel S Zuckier, Michael G Stabin, Borys R Krynyckyi, Pat Zanzonico, Barbara BinkertAbstract:Previously administered diagnostic and therapeutic radiopharmaceuticals may interfere with performance of the Schilling Test for prolonged periods of time. Additionally, presence of confounding radionuclides in the urine may not be suspected if baseline urine measurements have not been performed before the examination. Methods : We assumed that a spurious contribution of counts corresponding to 1% of the administered Schilling dose would begin to contribute clinically significant interference. Based on the typical amounts of radiopharmaceuticals administered, spectra of commonly used radionuclides and best available pharmacokinetic models of biodistribution and excretion, we estimated the interval required for 24-hr urinary excretion of diagnostic and therapeutic radiopharmaceuticals to drop below this threshold of significant interference. Results : For previously administered 99m Tc-based radiopharmaceuticals and 123 I-Nal, the interval required for urinary levels of activity to fall below thresholds of allowable interference are between 2-5 days. For 67 Ga-citrate, several 111 In compounds, 131 I-MIBG and 201 TI-thallous chloride, periods of 12-44 days are estimated. Estimates for 131 I-Nal vary greatly between 4 and 115 days, depending on the amount administered, and the degree of thyroid uptake. Conclusion : Patients should be interviewed before performing the Schilling Test to ensure that interfering radiopharmaceuticals have not been recently administered. The estimates developed in this paper can serve as guidelines for the necessary waiting time between prior radiopharmaceutical administration and the Schilling examination.
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accuracy in using dual isotope Schilling Test to measure urine samples a multicenter study
The Journal of Nuclear Medicine, 1995Co-Authors: Borys R Krynyckyi, Lionel S ZuckierAbstract:UNLABELLED: As a component of our quality assurance program, this multicenter study was performed to characterize the magnitude and types of error present in measurement of typical dual-isotope Schilling Test (DIST) urine samples. METHODS: A panel of three simulated DIST urine samples was formulated corresponding to diagnoses of normal excretion, malabsorption and pernicious anemia and was distributed to eight hospitals in our regional area (three novice and five experienced users). Count-rate data and urine volume measurements from each site were analyzed for accuracy against the predicted values and a carefully measured gold standard and were correlated with the methodology and equipment used. RESULTS: Three of 24 results were uninterpretable due to an overly low ratio of intrinsic factor bound to free vitamin B12 excretion (B/F ratio), inconsistent with possible diagnoses. In 20 of 21 interpretable samples, results corresponded to the appropriate diagnoses, with typical values noted in 18 of the cases and slightly atypical yet diagnostic values seen in the remaining two cases. In only one sample did values correspond to an erroneous diagnosis (low normal or partial malabsorption rather than pernicious anemia). The four major discrepancies (Test failure or misdiagnosis) were largely attributable to blunders and were limited to two of the three novice sites and to a single experienced site which had grossly inaccurate raw data (background greater than sample counts). CONCLUSION: Quantitation of vitamin B12 excretion in DIST urine samples is a reliable method of evaluation when performed by reasonably experienced and competent clinical laboratories. Improved accuracy may be obtained by increasing the stochastic certainty of the count data and by more careful measurement of the sample and urine volumes.
Erik M Magnus - One of the best experts on this subject based on the ideXlab platform.
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a new peroral non radioactive vitamin b12 absorption Test compared with the Schilling Test
European Journal of Haematology, 2009Co-Authors: Erik M Magnus, Carl MullerAbstract:: The results of a non-radioactive, peroral absorption Test have been compared with the results of the traditional Schilling Test in 31 cobalamin-deficient patients. The non-radioactive Test is simple to perform, is less costly than the Schilling Test and seems to give reliable results. The non-radioactive Test should be performed after cobalamin treatment, but not until the plasma cobalamin value has declined to below 450 pmol/l. Normal Schilling Test was noted in one-third of the patients, while normal non-radioactive Test was noted in only one-fifth of the patients. The results reveal some discrepancies between the two Tests regarding the response to intrinsic factor. In the non-radioactive Test without intrinsic factor, the great variation in values may reflect varying secretion of intrinsic factor, possibly secondary to infestation with Helicobacter pylori. "False normal" Schilling Test seems to be more common than previously believed.
Borys R Krynyckyi - One of the best experts on this subject based on the ideXlab platform.
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effect of prior radiopharmaceutical administration on Schilling Test performance analysis and recommendations
The Journal of Nuclear Medicine, 1996Co-Authors: Lionel S Zuckier, Michael G Stabin, Borys R Krynyckyi, Pat Zanzonico, Barbara BinkertAbstract:Previously administered diagnostic and therapeutic radiopharmaceuticals may interfere with performance of the Schilling Test for prolonged periods of time. Additionally, presence of confounding radionuclides in the urine may not be suspected if baseline urine measurements have not been performed before the examination. Methods : We assumed that a spurious contribution of counts corresponding to 1% of the administered Schilling dose would begin to contribute clinically significant interference. Based on the typical amounts of radiopharmaceuticals administered, spectra of commonly used radionuclides and best available pharmacokinetic models of biodistribution and excretion, we estimated the interval required for 24-hr urinary excretion of diagnostic and therapeutic radiopharmaceuticals to drop below this threshold of significant interference. Results : For previously administered 99m Tc-based radiopharmaceuticals and 123 I-Nal, the interval required for urinary levels of activity to fall below thresholds of allowable interference are between 2-5 days. For 67 Ga-citrate, several 111 In compounds, 131 I-MIBG and 201 TI-thallous chloride, periods of 12-44 days are estimated. Estimates for 131 I-Nal vary greatly between 4 and 115 days, depending on the amount administered, and the degree of thyroid uptake. Conclusion : Patients should be interviewed before performing the Schilling Test to ensure that interfering radiopharmaceuticals have not been recently administered. The estimates developed in this paper can serve as guidelines for the necessary waiting time between prior radiopharmaceutical administration and the Schilling examination.
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accuracy in using dual isotope Schilling Test to measure urine samples a multicenter study
The Journal of Nuclear Medicine, 1995Co-Authors: Borys R Krynyckyi, Lionel S ZuckierAbstract:UNLABELLED: As a component of our quality assurance program, this multicenter study was performed to characterize the magnitude and types of error present in measurement of typical dual-isotope Schilling Test (DIST) urine samples. METHODS: A panel of three simulated DIST urine samples was formulated corresponding to diagnoses of normal excretion, malabsorption and pernicious anemia and was distributed to eight hospitals in our regional area (three novice and five experienced users). Count-rate data and urine volume measurements from each site were analyzed for accuracy against the predicted values and a carefully measured gold standard and were correlated with the methodology and equipment used. RESULTS: Three of 24 results were uninterpretable due to an overly low ratio of intrinsic factor bound to free vitamin B12 excretion (B/F ratio), inconsistent with possible diagnoses. In 20 of 21 interpretable samples, results corresponded to the appropriate diagnoses, with typical values noted in 18 of the cases and slightly atypical yet diagnostic values seen in the remaining two cases. In only one sample did values correspond to an erroneous diagnosis (low normal or partial malabsorption rather than pernicious anemia). The four major discrepancies (Test failure or misdiagnosis) were largely attributable to blunders and were limited to two of the three novice sites and to a single experienced site which had grossly inaccurate raw data (background greater than sample counts). CONCLUSION: Quantitation of vitamin B12 excretion in DIST urine samples is a reliable method of evaluation when performed by reasonably experienced and competent clinical laboratories. Improved accuracy may be obtained by increasing the stochastic certainty of the count data and by more careful measurement of the sample and urine volumes.
M. H. Lucas - One of the best experts on this subject based on the ideXlab platform.
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Detection of Protein Bound Vitamin B: A Case Report and Review of the Literature12: A Case Report and Review of the Literature Malabsorption: A Case Report and Review of the Literature
Clinical Nuclear Medicine, 1994Co-Authors: M. H. Lucas, Elgazzar AhAbstract:The Schilling Test is used to identify the cause of vitamin B12 malabsorption in patients with low serum vitamin B12 levels. The initial step required for vitamin B12 absorption is a process of separation from the protein complexes of food. The crystalline Co-57 vitamin B12 used in the Schilling Test does not reproduce this physiologic process. Thus, a crystalline stage I Schilling Test may be normal even in the face of cobalamin malabsorption. An adjunctive stage I Schilling Test using Co-57 vitamin B12 bound to protein has been developed. The authors describe a patient with protein-bound vitamin B12 malabsorption whose crystalline Co-57 vitamin B12 stage I Schilling Test was normal. A subsequent stage I Schilling Test using Co-57 vitamin B12 bound to chicken serum revealed significant cobalamin malabsorption. A review of the history and literature of this diagnostic Test using protein bound vitamin B12 is also presented.
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Detection of protein bound vitamin B12 malabsorption. A case report and review of the literature.
Clinical Nuclear Medicine, 1994Co-Authors: M. H. Lucas, Elgazzar AhAbstract:: The Schilling Test is used to identify the cause of vitamin B12 malabsorption in patients with low serum vitamin B12 levels. The initial step required for vitamin B12 absorption is a process of separation from the protein complexes of food. The crystalline Co-57 vitamin B12 used in the Schilling Test does not reproduce this physiologic process. Thus, a crystalline stage I Schilling Test may be normal even in the face of cobalamin malabsorption. An adjunctive stage I Schilling Test using Co-57 vitamin B12 bound to protein has been developed. The authors describe a patient with protein-bound vitamin B12 malabsorption whose crystalline Co-57 vitamin B12 stage I Schilling Test was normal. A subsequent stage I Schilling Test using Co-57 vitamin B12 bound to chicken serum revealed significant cobalamin malabsorption. A review of the history and literature of this diagnostic Test using protein bound vitamin B12 is also presented.
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Detection of protein bound vitamin B12 malabasorption
Clinical Nuclear Medicine, 1994Co-Authors: M. H. Lucas, A.-h. H. ElgazzarAbstract:The Schilling Test is used to identify the cause of vitamin B 12 malabsorption in patients with low serum vitamin B 12 levels. The initial step required for vitamin B 12 absorption is a process of separation from the protein complexes of food. The crystalline Co-57 vitamin B 12 used in the Schilling Test does not reproduce this physiologic process. Thus, a crystalline stage I Schilling Test may be normal even in the face of cobalamin malabsorption. An adjunctive stage I Schilling Test using Co-57 vitamin B 12 bound to protein has been developed. The authors describe a patient with protein-bound vitamin B 12 malabsorption whose crystalline Co-57 vitamin B 12 stage I Schilling Test was normal. A subsequent stage I Schilling Test using Co-57 vitamin B 12 bound to chicken serum revealed significant cobalamin malabsorption
