29 results on '"Mg Woldring"'
Search Results
2. Scintigraphy with 57Co-bleomycin in the detection of lung cancer: A review of 268 well-documented patients
- Author
-
Da Piers, H. Beekhuis, Mg Woldring, OE Nieweg, Hj Sluiter, and Am Vanderwal
- Subjects
Cancer Research ,Pathology ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine.disease ,Bleomycin ,Scintigraphy ,law.invention ,chemistry.chemical_compound ,Oncology ,chemistry ,law ,medicine ,Histologic type ,Adenocarcinoma ,Anaplastic carcinoma ,Respiratory system ,business ,Lung cancer ,Gamma camera - Abstract
Over a 5-year period /sup 57/Co-bleomycin scintigraphy for tumor detection was performed with a large-field-of-view gamma camera. The scintigrams of 268 patients with lung cancer, with a benign lesion, or with no abnormality in the chest, were reviewed. A sensitivity of 96% was found. In a group of 193 patients in whom a preoperative pathologic diagnosis could not be obtained sensitivity was 95%, specificity was 87%. Correlation between tumor size and tumor-to-non-tumor ratio was established for squamous cell carcinoma, adenocarcinoma, and small cell anaplastic carcinoma. Adenocarcinomas were smaller and showed lower tumor-to-non-tumor ratios than other histologic types. In squamous cell carcinoma a possible correlation between tumor-to-non-tumor ratio and histologic differentiation was investigated, but could not be established. It is concluded that /sup 57/Co-bleomycin scintigraphy is helpful in the evaluation of patients with possible lung cancer in whom a preoperative pathologic diagnosis cannot be obtained.
- Published
- 1984
3. 57Co-bleomycin scintigraphy for the staging of lung cancer
- Author
-
OE Nieweg, DA Piers, Mg Woldring, H. J. Sluiter, H. Beekhuis, and A. M. van der Wal
- Subjects
Cancer Research ,medicine.diagnostic_test ,business.industry ,Respiratory disease ,Mediastinum ,Hilum (biology) ,respiratory system ,Scintigraphy ,medicine.disease ,Bleomycin ,respiratory tract diseases ,Mediastinoscopy ,chemistry.chemical_compound ,medicine.anatomical_structure ,Oncology ,chemistry ,medicine ,business ,Lung cancer ,Nuclear medicine ,Lymph node - Abstract
The value of Cobalt-57 bleomycin (57Co-BLM) scintigraphy in the detection of lymph node metastases in the hilum and mediastinum was investigated in 132 patients with peripherally located lung cancer. In one half of the patients with metastases, these were visualized. Specificity was 98%. These results were better than those obtained with chest radiography and conventional roentgen tomography. 57Co-BLM scintigraphy is routinely used in the staging of patients with lung cancer, obviating the need for mediastinoscopy.
- Published
- 1989
4. Detection of lung cancer with 55Co-bleomycin using a positron camera
- Author
-
T Wiegman, J. Welleweerd, OE Nieweg, Anne M. J. Paans, Mg Woldring, W Vaalburg, Da Piers, and Beekhuis H
- Subjects
Male ,medicine.medical_specialty ,Lung Neoplasms ,Scintigraphy ,Bleomycin ,Positron camera ,chemistry.chemical_compound ,Positron ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Cobalt Radioisotopes ,Lung cancer ,Radionuclide Imaging ,False Negative Reactions ,Aged ,Neoplasm Staging ,Lung ,medicine.diagnostic_test ,business.industry ,Single photon imaging ,General Medicine ,respiratory system ,Middle Aged ,medicine.disease ,respiratory tract diseases ,carbohydrates (lipids) ,Radiography ,medicine.anatomical_structure ,chemistry ,Carcinoma, Squamous Cell ,Radiology ,business ,Nuclear medicine ,Half-Life - Abstract
57-Co-bleomycin is useful in the detection and staging of lung cancer, but the long half-life of 57Co (270 days) has discouraged its widespread acceptance. We investigated the shorter living positron emitting 55Co (half-life 18.2 h) as a level for bleomycin. In eleven patients with proven lung cancer scintigraphy with 55Co-bleomycin, using a positron camera, demonstrated the tumor in ten cases. Tumor to lung ratios were calculated. The results were superior to those obtained with 55Co-bleomycin single photon imaging but inferior to those obtained with 57Co-bleomycin scintigraphy.
- Published
- 1982
5. Rapid decar☐ylation of carbon-11 labelleddl-dopa in the brain: A potential approach for external detection of nervous structures
- Author
-
Mg Woldring, Anne M. J. Paans, W Vaalburg, Jakob Korf, H.D. Beerling-van der Molen, J.P.W.F. Lakke, and S. Reiffers
- Subjects
Male ,Cerebellum ,Premedication ,Striatum ,Pharmacology ,Receptors, Dopamine ,Hydroxydopamines ,medicine ,Haloperidol ,Animals ,Distribution (pharmacology) ,Neurotoxin ,Receptors, Cholinergic ,Carbon Radioisotopes ,Radionuclide Imaging ,Molecular Biology ,Chemistry ,General Neuroscience ,Brain ,Carbidopa ,Corpus Striatum ,Dihydroxyphenylalanine ,Rats ,medicine.anatomical_structure ,Catecholamine ,Occipital Lobe ,Neurology (clinical) ,Free nerve ending ,Brain Stem ,Developmental Biology ,medicine.drug - Abstract
The cerebral distribution of the positron-emitting agent [1- 11 C]β-(3,4-dihydroxyphenyl) - d,l -α-alanine ([ 11 C]DOPA) was studied after intravenous injection in rats pretreated with the peripheral decar☐ylase inhibitor, carbidopa. Within 15 min of injection the accumulation of carbon-11 was almost twice as high in cortical areas and cerebellum as in the striatum and the brain stem. After destruction of catecholamine containing nerve endings with 6-hydroxydopamine, the level of carbon-11 in the striatum was higher than in rats not treated with this neurotoxin. Pretreatment of rats with haloperidol or l -DOPA did not change the distribution pattern of carbon-11. Without pretreatment with carbidopa a uniform distribution of the label in the brain was observed. We suggest that [ 11 DOPA is a potentially useful agent external detection with positron imaging systems in patients and large animals of brain regions rich in the enzyme dopa-decar☐ylase. (EC 4. 1.1.26).
- Published
- 1978
6. Fast recovery by dry distillation of 75Br induced in reusable metal selenide targets via the 76Se(p,2n)75Br reaction
- Author
-
Anne M. J. Paans, T Wiegman, A. Rijskamp, Mg Woldring, Jw Terpstra, W Vaalburg, and K. Dekens
- Subjects
Radiation ,Proton ,Radiochemistry ,chemistry.chemical_element ,Dry distillation ,law.invention ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,law ,Yield (chemistry) ,Selenide ,Isotopes of bromine ,Radiology, Nuclear Medicine and imaging ,Irradiation ,Platinum ,Distillation ,Nuclear chemistry - Abstract
A number of metal selenides were investigated as target material for the production of 75Br by the 76Se(p,2n)75Br reaction. Ag2Se, CuAgSe, and Cu2Se met the rqquirements for an economical and fast production procedure. These selenides were found to be stable during bombardment with 1–4 μA 28 MeV protons (beam dimension 0.4 cm2) and at the dry distillation temperature of 1473 K. A target system was developed for radiobromine production with a 7 μA 28−22 MeV proton beam on Cu2Se. At EOB the calculated thick target yield is 1.59 GBq/μAh (43 mCi/μAh) and the radionuclidic purity is 98.6%. The radiobromine was separated from Cu2Se by dry distillation at 1473 K and collected for 80–95% on platinum wool pretreated with CaCl2. Radiochemical analysis showed the radiobromine to be Br− for 95% and BrO3− for 5%. The total loss of selenide after irradiation and distillation was found to be less than 0.1%.
- Published
- 1985
7. Syntheses of carbon-11 labelled ornithine and lysine. Preliminary accumulation studies in rats with Walker 256 carcinosarcoma
- Author
-
Mg Woldring, Anne M. J. Paans, W Vaalburg, J.B. Zijlstra, Hans Wynberg, Jm Bolster, and T. H. van Dijk
- Subjects
Male ,Ornithine ,Lysine ,Walker 256 carcinosarcoma ,complex mixtures ,chemistry.chemical_compound ,Walker Carcinosarcoma 256 ,Animals ,Radiology, Nuclear Medicine and imaging ,Carbon Radioisotopes ,Carcinoma 256, Walker ,Radionuclide Imaging ,Radiation ,Chemistry ,Rats, Inbred Strains ,Biological activity ,Rats ,Nuclear Energy and Engineering ,Biochemistry ,Carboxylation ,Isotope Labeling ,Yield (chemistry) ,bacteria ,Female ,Neoplasm Transplantation - Abstract
DL-[1-11C]ornithine and lysine have been synthesized by carboxylation of the corresponding alpha-lithioisocyanide with a radiochemical yield of up to 14% without correction for decay. The total preparation time is 50 min. Accumulation of both DL-[1-11C]ornithine and lysine in Walker 256 carcinosarcoma is observed, with a tumor/non-tumor ratio of 4.9 and 4.5 respectively, at 45 min after intravenous injection.
- Published
- 1985
8. Evaluation of Carbon-11 Labelled Phenylglycine and Phenylalanine for Pancreas Scintigraphy
- Author
-
Mg Woldring, Hd Beerlingvandermolen, and W Vaalburg
- Subjects
chemistry.chemical_classification ,medicine.medical_specialty ,medicine.diagnostic_test ,Spleen ,Phenylalanine ,General Medicine ,Scintigraphy ,Amino acid ,chemistry.chemical_compound ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Biochemistry ,Internal medicine ,medicine ,Aromatic amino acids ,Radiology, Nuclear Medicine and imaging ,Pancreas - Abstract
SummaryCarbon-11 (t½ = 20.4 min, β+) labelled DL-α-phenylalanine and DL-α-phenylglycine were administered intravenously to rats and the distribution of the radioactive amino acids over pancreas, liver, spleen, kidneys and blood was measured after several time intervals. From these results the ratios of the concentration in pancreas and liver were calculated and compared with the corresponding ratios from the literature for some 18F-labelled aromatic amino acids and L-selenomethionine-75Se. On the basis of this study it appears that DL-α-phenylglycine-l-11C, in spite of a small percentage of the administered dose reaching the pancreas, and DL-α-phenylalanine-l-11C are better suited to pancreas scintigraphy than L-selenomethionine-75Se.
- Published
- 1975
9. An improved method for the cyclotron production of 13N-labelled ammonia
- Author
-
J.A.A. Kamphuis, H.D. Beerling-van der Molen, A. Rijskamp, S. Reiffers, W Vaalburg, and Mg Woldring
- Subjects
Nitrogen Radioisotopes ,Radiation ,Chemistry ,Cyclotron ,Radiochemistry ,Improved method ,Alpha particle ,law.invention ,Ammonia ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,law ,Isotope Labeling ,Radiology, Nuclear Medicine and imaging - Published
- 1975
10. Rapid conversion of a homocystine-containing peptide into its corresponding 11CH3-labeled methionine sulfone analogue. PET experiments with H-[S-11CH3]Met(O2)-Glu-His-Phe-D-Lys-Phe-OH
- Author
-
Mg Woldring, D. de Wied, Anne M. J. Paans, T Wiegman, W Vaalburg, W. P. A. Janssen, J.F.G.A. Jansen, and J. W. Van Nispen
- Subjects
chemistry.chemical_classification ,Homocystine ,Phe-D-Lys-Phe ,Chemistry ,Stereochemistry ,Organic Chemistry ,Drug Discovery ,Radiology, Nuclear Medicine and imaging ,Peptide ,Biochemistry ,Spectroscopy ,Methionine sulfone ,Analytical Chemistry - Published
- 1989
11. A comparison of the sensitivity of PET and NMR for in vivo quantitative metabolic imaging
- Author
-
Mg Woldring, Anne M. J. Paans, and W Vaalburg
- Subjects
Carbon Isotopes ,Magnetic Resonance Spectroscopy ,medicine.diagnostic_test ,business.industry ,Chemistry ,Metabolic imaging ,Relaxation (NMR) ,Physics::Medical Physics ,General Medicine ,Nuclear magnetic resonance spectroscopy ,Nuclear magnetic resonance ,Metabolism ,Positron emission tomography ,In vivo ,medicine ,Radiology, Nuclear Medicine and imaging ,Sensitivity (control systems) ,Carbon Radioisotopes ,Nuclear medicine ,business ,Tomography, Emission-Computed - Abstract
Using positron emission tomography (PET) in combination with compounds labelled with positron-emitting radionuclides like 11C, 13N and 15O, it is possible to study metabolism in vivo in a non-invasive way. Nuclear magnetic resonance (NMR) imaging takes advantage of the spin of protons in water molecules to measure both their number and relaxation times in vivo, but is, in principle, not limited to protons and can also be used for other nuclei with a non-zero spin, e.g. 13C and 31P. The use of 13C opens the possibility of studying the metabolism of a large number of compounds. In order to choose the appropriate methodology for metabolic imaging, i.e. PET or NMR, it is important to know the sensitivity of each modality. The present study outlines the sensitivity of both techniques.
- Published
- 1985
12. Rapid Synthesis of π-Phenylglycine by Carboxylation of π-Lithiobenzylisocyanide
- Author
-
Mg Woldring, J. Strating, Hans Wynberg, and W Vaalburg
- Subjects
chemistry.chemical_classification ,Hydrolysis ,chemistry ,Carboxylation ,Yield (chemistry) ,Organic Chemistry ,Organic chemistry ,Combinatorial chemistry ,Amino acid - Abstract
An expanding field of interest in nuclear medicine is the preparation of radiopharmaceuticals labelled with cyclorrn produced isotopes of short half life.1–3 In an investigation to prepare 11C-labelled amino acids we developed a new and repid synthesis for the preparation of a-phenylglycine. The preparation of other amino acids by this route is under investigation. α-Lithiobenzylisocyande4 was treated with carbondioxyde and the intermediate was hydrolysed to the amino acid. The overall yield (75–808) was accomplished in 50–70 minutes.+
- Published
- 1972
13. 57Co-bleomycin and 67Ga-citrate in detecting and staging lung cancer
- Author
-
DA Piers, A. M. van der Wal, Mg Woldring, O E Nieweg, H. J. Sluiter, and H Beekhuis
- Subjects
Pulmonary and Respiratory Medicine ,Adult ,Male ,medicine.medical_specialty ,Lung Neoplasms ,medicine.medical_treatment ,Hilum (biology) ,Gallium Radioisotopes ,Bleomycin ,Scintigraphy ,Malignancy ,Mediastinoscopy ,chemistry.chemical_compound ,medicine ,Humans ,Thoracotomy ,Cobalt Radioisotopes ,Lung cancer ,Radionuclide Imaging ,Aged ,Neoplasm Staging ,medicine.diagnostic_test ,business.industry ,Mediastinum ,respiratory system ,Middle Aged ,medicine.disease ,respiratory tract diseases ,medicine.anatomical_structure ,chemistry ,Lymphatic Metastasis ,Female ,Radiology ,business ,Research Article - Abstract
In the investigation of suspected lung cancer bleomycin labelled with cobalt-57 and gallium-67 labelled with citrate are currently used to detect the primary tumour and to establish the presence of metastases in the lung hilum and mediastinum. A comparative study of these radio-pharmaceuticals was performed in 63 patients with proved lung cancer. 57Co-bleomycin showed the primary tumour in 58 patients (92%) and 67 Ga-citrate in 34 (54%) (p less than 0.01). The average tumour-to-lung ratio was 3.4 with 57Co-bleomycin and 1.5 with 67Ga-citrate. Proved metastases in the hilum or the mediastinum were visualised with 57Co-bleomycin scintigraphy in 16 out of 18 patients (89%) and with 67 Ga-citrate scintigraphy in only eight (45%) (p less than 0.01). These results indicate that 57Co-bleomycin scintigraphy is more suitable for detecting and staging lung cancer than is 67Ga-citrate. 57Co-bleomycin is valuable in the detection of peripheral lesions, in which a pathological diagnosis is difficult to achieve, since a positive scintigram indicates malignancy. When 57Co-bleomycin scintigraphy suggests hilar or mediastinal metastases mediastinoscopy should be carried out; but when no metastases are apparent it is reasonable to proceed directly to thoracotomy without mediastinoscopy.
- Published
- 1983
14. The preparation of carbon-11 labelled proline for positron emission tomography. Preliminary distribution studies in rats with Walker 256 carcinosarcoma
- Author
-
W. Ten Hoeve, Mg Woldring, J.B. Zijlstra, Jm Bolster, Anne M. J. Paans, Hans Wynberg, T. H. van Dijk, and W Vaalburg
- Subjects
Proline ,chemistry.chemical_element ,Walker 256 carcinosarcoma ,Nuclear magnetic resonance ,medicine ,Distribution (pharmacology) ,Animals ,Radiology, Nuclear Medicine and imaging ,Carbon Radioisotopes ,Carcinoma 256, Walker ,Radiation ,medicine.diagnostic_test ,Chemistry ,Radiochemistry ,Total synthesis ,Rats, Inbred Strains ,Stereoisomerism ,Rats ,Nuclear Energy and Engineering ,Carboxylation ,Positron emission tomography ,Yield (chemistry) ,Isotope Labeling ,Female ,Carbon ,Neoplasm Transplantation ,Tomography, Emission-Computed - Abstract
DL -[1- 11 C]Proline has been synthesized by carboxylation of α-lithiopyrrolidyl-N-tert-butyl-formamidine with a radiochemical yield of up to 18% without correction for decay. The total synthesis time is 45 min. Accumulation of DL -[1- 11 C]-proline has been shown in Walker 256 carcinosarcoma transplanted in rats. A tumor/non-tumor ratio of 5.9 was found at 45 min after i.v. injection.
- Published
- 1985
15. Rapid synthesis and purification of carbon-11 labelled DOPA: a potential agent for brain studies
- Author
-
Anne M. J. Paans, H.D. Beerling-van der Molen, W. Ten Hoeve, W Vaalburg, Mg Woldring, Jakob Korf, S. Reiffers, and Hans Wynberg
- Subjects
chemistry.chemical_classification ,Male ,Radiation ,Carboxylic acid ,chemistry.chemical_element ,Brain ,Carbidopa ,Dihydroxyphenylalanine ,Rats ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Carboxylation ,Dopamine ,medicine ,Organic chemistry ,Animals ,Radiology, Nuclear Medicine and imaging ,Carbon Radioisotopes ,Radionuclide Imaging ,Carbon ,medicine.drug - Abstract
A rapid methods for preparation and purification of β-(3,4-dihydroxyphenyl)- D,L -α-alanine-1-11C (11C-DOPA), using 11CO2 as the radioactive precursor is described. Carboxylation of an α-lithioisocyanide, containing protected hydroxylic groups, was followed by a three-step hydrollsis of the intermediate α-isocyano carboxylic acid. Preliminary experiments in rats indicate that the compound is preferentially decarboxylated in brain areas rich in dopamine containing neurons.
- Published
- 1977
16. Preparation of carbon-11 labelled phenylalanine and phenylglycine by a new amino acid synthesis
- Author
-
S. Reiffers, A. Rijskamp, W. Vaalburg, Mg Woldring, Hans Wynberg, and H.D. Beerling-van der Molen
- Subjects
chemistry.chemical_classification ,Radiation ,Phenylalanine ,Glycine ,chemistry.chemical_element ,Pancreatic Diseases ,Amino acid ,Hydrolysis ,Nuclear Energy and Engineering ,chemistry ,Carboxylation ,Isotope Labeling ,Organic chemistry ,Radiology, Nuclear Medicine and imaging ,Carbon Radioisotopes ,Radionuclide Imaging ,Carbon ,Amino acid synthesis - Abstract
Of the cyclotron-produced short-lived isotopes carbon-11 (t12 = 20.4 min; β+) is one of the most promising as label for radiopharmaceuticals. To prepare 11C-labelled amino acids for evaluation as pancreas scanning agents a new rapid amino acid synthesis was developed. The method is based on the carboxylation of α-lithioisocyanides with 11CO2, followed by hydrolysis of the intermediate reaction product to the desired amino acid. By this method DL-α-phenylalanine-1-11C and DL-α-phenylglycine-1-11C were prepared. The precursor 11CO2 was produced via the 14N(p, α)11C reaction by bombardment of a flow of nitrogen gas mixed with 0.1% O2 with 20 MeV protons. The target system is described.
- Published
- 1976
17. Comparison of Methods to Calculate Regional Lung Volume and Specific Alveolar Ventilation from Xenon-133 Wash-in Curves
- Author
-
Mg Woldring, R Peset, Th. W. van der Mark, and Beekhuis H
- Subjects
Partition coefficient ,Xenon ,Chemistry ,Analytical chemistry ,chemistry.chemical_element ,Lung volumes ,Regional lung volume ,respiratory system - Abstract
Wash-in curves for physiologically inert gases are usually described by a mono-exponential function of the type N(t) = N∞(l−e−kt). N∞ is related to lung volume and K is the specific alveolar ventilation, or alveolar ventilation per unit lung volume. Determination of the specific alveolar ventilation therefore recess takes an estimate of ? from the measured curve. Compared with other gases Xenon-133 is fairly soluble in blood (blood-gas partition coefficient λ = 0.152). This gives rise to multiexponential curves3.
- Published
- 1982
18. Synthesis of no-carrier-added L- and D-[1-11C]-DOPA
- Author
-
W Vaalburg, W Vanveen, Hd Vandermolen, Jm Bolster, Th Vandijk, Hans Wynberg, and Mg Woldring
- Subjects
Radiation ,Chromatography ,Resolution (mass spectrometry) ,Isocyanide ,Total synthesis ,Brain ,High-performance liquid chromatography ,Dihydroxyphenylalanine ,Levodopa ,chemistry.chemical_compound ,Column chromatography ,Nuclear Energy and Engineering ,chemistry ,Carboxylation ,Yield (chemistry) ,Isotope Labeling ,Neoplasms ,Humans ,Radiology, Nuclear Medicine and imaging ,Aliphatic compound ,Radionuclide Imaging - Abstract
No-carrier-added DL -[1- 11 C]-DOPA has been synthesized by carboxylation of an α-lithioisocyanide with a radiochemical yield of up to 15% without correction for decay. The total synthesis time is 30 min. The resolution of the D - and L -isomers was accomplished within 16 min by HPLC using a chiral stationary phase and a phosphate buffer of pH 4.5 as eluent.
- Published
- 1983
19. Competitive protein-binding analysis of vitamin B12 using Lactobacillus leichmannii as a specific binder
- Author
-
Ho Nieweg, Mg Woldring, Ja Devries, and [No Value] Vandewie.Df
- Subjects
Vitamin ,Time Factors ,Clinical Biochemistry ,Centrifugation ,Acetates ,Buffers ,Biochemistry ,Binding, Competitive ,Phosphates ,chemistry.chemical_compound ,Radioligand Assay ,Lactobacillus ,Bioassay ,Vitamin B12 ,Binding site ,Cobalt Radioisotopes ,Disposable Equipment ,Chromatography ,Binding Sites ,biology ,Syringes ,Biochemistry (medical) ,Osmolar Concentration ,Temperature ,General Medicine ,Hydrogen-Ion Concentration ,biology.organism_classification ,Hormones ,Anti-Bacterial Agents ,Vitamin B 12 ,chemistry ,Evaluation Studies as Topic ,Biological Assay ,Bacteria ,Filtration ,Protein Binding - Abstract
Vitamin B12 was assayed by the competitive protein binding method, using Lactobacillus leichmannii as binding agent. The intact bacteria were used as “solid phase”, and separation of bound and free vitamin B12 was obtained simply by filtration of the bacteria. Filtration could be rapidly done using a disposable syringe provided with a filter. Optimal conditions with respect to the extraction of vitamin B12 from serum and binding of the vitamin to the bacteria were determined. The effect of several drugs and hormones on the assayed vitamin B12 concentration was investigated. The correlation with the Lactobacillus leichmannii bioassay was calculated.
- Published
- 1974
20. Synthesis of carbon-11 labelled glycine and the dipeptides L-phenylalanylglycine and L-leucylglycine
- Author
-
W Vaalburg, Mg Woldring, Jm Bolster, Hans Wynberg, and Philippus Elsinga
- Subjects
Carbon Isotopes ,Dipeptide ,Stereochemistry ,General Engineering ,Glycine ,chemistry.chemical_element ,Dipeptides ,L-phenylalanylglycine ,High-performance liquid chromatography ,chemistry.chemical_compound ,chemistry ,Carboxylation ,Yield (chemistry) ,Isotope Labeling ,Leucylglycine ,Indicators and Reagents ,Carbon ,Nuclear chemistry - Abstract
Carbon-11 labelled glycine has been prepared in 30 min by carboxylation of α-lithiomethylisocyanide with a radiochemical yield of 10–15%. After coupling with L -phenylalanine-N-carboxyanhydride and L -leucine-N-carboxyanhydride followed by HPLC purification, the corresponding dipeptides were obtained in 20 min with a radiochemical yield of 30–40%. Consequently, starting with 11 CO 2 , non carrier added L -phenylalanyl[1- 11 C]glycine and L -leucyl[1- 11 C]glycine in 0.1 N NaH 2 PO 4 were obtained in 50 min with a radiochemical yield of 3–6%. The radiochemical yield figures are not corrected for decay.
- Published
- 1986
21. Carbon-11 labelled tyrosine to study tumor metabolism by positron emission tomography (PET)
- Author
-
Hans Wynberg, Jm Bolster, Philippus Elsinga, W Vaalburg, Th Vandijk, J.B. Zijlstra, Amj Paans, Da Piers, Mg Woldring, and Nanno Mulder
- Subjects
Male ,Isocyanide ,medicine.medical_treatment ,Breast Neoplasms ,High-performance liquid chromatography ,chemistry.chemical_compound ,Positron ,medicine ,Meningeal Neoplasms ,Animals ,Humans ,Radiology, Nuclear Medicine and imaging ,Carbon Radioisotopes ,Saline ,medicine.diagnostic_test ,business.industry ,Radiochemistry ,Liver Neoplasms ,General Medicine ,Neoplasms, Experimental ,Neoplasm Proteins ,Rats ,Solvent ,chemistry ,Positron emission tomography ,Yield (chemistry) ,Tyrosine ,Female ,Enantiomer ,Nuclear medicine ,business ,Tomography, Emission-Computed - Abstract
To measure the rate of protein synthesis in human neoplasms by positron emission tomography, we prepared no carrier added DL-(1-11C)-tyrosine by 11C-carboxylation of the appropriate alpha-lithioisocyanide followed by hydrolysis of the isocyanide function and removal of the protecting methoxy group. The purification, resolution and solvent switch to saline was performed by high performance liquid chromatography (HPLC). DL-(1-11C)-Tyrosine in 0.1 N NaH2PO4 buffer was prepared with a radiochemical yield of 8%-16% (EOS, 35 min). The enantiomeric separation and solvent switch to saline were achieved in 5 min and 10 min respectively. Consequently L-(1-11C)-tyrosine in physiological saline was obtained in 2%-4% radiochemical yield. Tumor accumulation in rats with the experimental WALKER 256 carcinosarcoma was observed for both the L- and D-isomer. Using positron emission tomography a tumor/muscle ratio of two was observed for the L-isomer 15 min after injection. The corresponding figure for the D-isomer was 2.5. The first clinical results with DL-(1-11C)-tyrosine show accumulation of radioactivity in meningioma, a primary breast carcinoma and in liver metastases of a colonic carcinoma.
- Published
- 1986
22. Production of 13N‐labelled molecular nitrogen for pulmonary function studies
- Author
-
W Vaalburg, Mg Woldring, A. Steenhoek, R. Peset, Anne M. J. Paans, and S. Reiffers
- Subjects
Molecular nitrogen ,Chemistry ,Organic Chemistry ,Irradiation time ,Biochemistry ,Analytical Chemistry ,Pulmonary function testing ,Drug Discovery ,Radiology, Nuclear Medicine and imaging ,Irradiation ,Current (fluid) ,Spectroscopy ,Beam (structure) ,Nuclear chemistry ,Injectable Solution - Abstract
A method for the production of 13NN either as a gas or as an injectable solution is described. The method is based on the 16O(p,α)13N reaction and water as target material. Following irradiation, the 13NO2- and 13NO3- are reduced to 13NH3, followed by NaOBr oxidation to 13NN. With a beam current of 1 μA and 20 min irradiation time the injectable solution contained 148 MBq (4 mCi) per ml.
- Published
- 1981
23. Excitation functions for the production of bromine-75: a potential nuclide for the labelling of radiopharmaceuticals
- Author
-
J. Welleweerd, S. Reiffers, Anne M. J. Paans, Mg Woldring, and W Vaalburg
- Subjects
Excitation function ,Bromides ,Radioisotopes ,Radionuclide ,Radiation ,Bromine ,Radiochemistry ,Proton ,Chemistry ,chemistry.chemical_element ,Helium ,Charged particle ,Arsenic ,Selenium ,Nuclear Energy and Engineering ,Pharmaceutical Preparations ,Isotope Labeling ,Technology, Pharmaceutical ,Radiology, Nuclear Medicine and imaging ,Nuclide ,Excitation - Abstract
Based on a theoretical evaluation of the charged particle induced reactions leading to 75 Br the four most promising reactions, 76 Se (p,2n) 75 Br , 76 Se (d,3n) 75 Br , 75 As ( 3 He ,3n) 75 br and 75 As ( 4 He ,4n) 75 Br , were selected for excitation function measurements. From the measured excitation functions the production rates and radionuclide purities were calculated. The proton induced reaction on 76 Se showed the highest production rate (118 mCi/μAh) while the contamination of the undesired nuclide 76 Br is limited to 1.4%.
- Published
- 1980
24. ESTIMATION OF PLASMA TESTOSTERONE WITHOUT EXTRACTION AND CHROMATOGRAPHY
- Author
-
Mg Woldring, T Wiegman, Jj Pratt, Re Lappohn, and Faculteit Medische Wetenschappen/UMCG
- Subjects
Male ,Clinical Biochemistry ,Serum albumin ,Radioimmunoassay ,Cross Reactions ,Tritium ,Biochemistry ,Binding, Competitive ,Animals ,Humans ,Testosterone ,Chromatography ,biology ,Human blood ,Chemistry ,Biochemistry (medical) ,Extraction (chemistry) ,Infant, Newborn ,Testosterone (patch) ,Dihydrotestosterone ,Serum Albumin, Bovine ,General Medicine ,Menstruation ,Evaluation Studies as Topic ,biology.protein ,Cattle ,Female ,Rabbits ,Antibody - Abstract
A new radioimmunoassay for plasma testosterone in human blood plasma is described. The assay is performed directly upon the plasma without extraction and purification of the testosterone. Antibodies to testosterone-7α-carboxyethyl thioether-bovine serum albumin are used and data concerning the specificity of these antibodies are given.
- Published
- 1975
25. Production and purification of antibody against protein-vitamin b12 conjugates for radioimmunoassay purposes
- Author
-
W.Th. Goedemans, D.F.M. van de Wiel, and Mg Woldring
- Subjects
Intrinsic Factor ,Swine ,Clinical Biochemistry ,Radioimmunoassay ,Diamines ,Biochemistry ,Antibodies ,Chromatography, Affinity ,Folic Acid ,Antigen ,Affinity chromatography ,Ethylamines ,Animals ,Vitamin B12 ,Cobalt Radioisotopes ,Cellulose ,Polyacrylamide gel electrophoresis ,Intrinsic factor ,Chromatography ,biology ,Chemistry ,Biochemistry (medical) ,Albumin ,Serum Albumin, Bovine ,General Medicine ,Electrophoresis, Disc ,Vitamin B 12 ,Lactates ,biology.protein ,Acridines ,Rabbits ,Antibody ,Protein Binding - Abstract
Antibodies have been evoked against vitamin B 12 conjugates using two types of antigen: intrinsic factor saturated with vitamin B 12 and vitamin B 12 covalently coupled to albumin. The antibodies were purified by rivanol and identified by polyacrylamide gel electrophoresis. Purified and unpurified anti-bodies were both applied in a radioimmunoassay for vitamin B 12 . Affinity chromatography proved to be a useful method for purification of the vitamin B 12 antibodies. An immunoadsorbent of vitamin B 12 covalently coupled to aminoethylcellulose was used.
- Published
- 1974
26. A new cocktail for liquid scintillation counting of aqueous radioimmunoassay-samples
- Author
-
Mg Woldring, Jj Pratt, and T. Wiegman
- Subjects
Clinical Biochemistry ,Radioimmunoassay ,Xylenes ,Tritium ,Biochemistry ,law.invention ,Polyethylene Glycols ,chemistry.chemical_compound ,Organophosphorus Compounds ,Drug Stability ,law ,Testosterone ,Carbon Radioisotopes ,Chemiluminescence ,Scintillation ,Reproducibility ,Aqueous solution ,Chromatography ,Chemistry ,Biochemistry (medical) ,Liquid scintillation counting ,Counting efficiency ,Xylene ,General Medicine ,Blood ,Solubility ,Evaluation Studies as Topic ,Indicators and Reagents ,Steroids ,Luminescence - Abstract
The aim of this investigation was to find a scintillation mixture for counting up to 1 ml of plasma. We succeeded in obtaining a mixture of xylene/Triton X-100/mono- and di-butylphosphate, and called it Plasmasol. The properties were ideal for radioimmunoassays of steroids. Good dissolving properties, high counting efficiency, absence of chemiluminescence and a good stability and reproducibility with respect to the disintegrations per minute were achieved. The cost was only 25% of the commercially available ready-to-use liquid scintillation mixtures, with which a comparison was made.
- Published
- 1975
27. Specificity of immunoassays. I. Effect of plasma proteins on the specificity of steroid immunoassay
- Author
-
W. Koops, Jj Pratt, Mg Woldring, and T Wiegman
- Subjects
Chromatography ,medicine.diagnostic_test ,biology ,Chemistry ,medicine.medical_treatment ,Radioimmunoassay ,General Medicine ,Cross Reactions ,Blood proteins ,Steroid ,Standard curve ,Homogeneous ,Solid phase radioimmunoassay ,Immunoassay ,medicine ,biology.protein ,Radiology, Nuclear Medicine and imaging ,Testosterone ,Antibody ,Aldosterone ,Progesterone ,Serum Albumin - Abstract
The theory of the measurement of the specificity of antigen binding by antibodies is reviewed. The specificity of steroid immunoassay has been investigated using a new solid phase radioimmunoassay system. The effects of plasma proteins on the specificity of the immunoassays have been tested. The methods used and the conclusions reached have been tested with homogeneous antibodies in order to simplify the interpretation of the results obtained. A new criterium of antibody homogeneity is proposed. The importance of correcting all results accurately for “non-specific binding” is emphasised. A new method for plotting radioimmunoassay standard curves is presented.
- Published
- 1976
28. Synthesis of dl-[1-11C]methionine
- Author
-
Hans Wynberg, Mg Woldring, Jm Bolster, W Vaalburg, and Philippus Elsinga
- Subjects
Methionine ,Isocyanide ,General Engineering ,11c methionine ,chemistry.chemical_compound ,Carboxylation ,chemistry ,Isotope Labeling ,Yield (chemistry) ,Organic chemistry ,Indicators and Reagents ,Carbon Radioisotopes ,Aliphatic compound ,Nuclear chemistry - Abstract
dl -[1-11C]methionine has been synthesized by carboxylation of the corresponding α-lithioisocyanide with a radiochemical yield of 8–14% (EOS, 35 min).
- Published
- 1986
29. Lithium and Thyrotoxicosis
- Author
-
W.J. Sluiter, K. Bakker, H. Doorenbos, and Mg Woldring
- Subjects
chemistry ,business.industry ,Radiochemistry ,Follow up studies ,chemistry.chemical_element ,Medicine ,Lithium ,General Medicine ,business ,Iodine Radioisotopes - Published
- 1976
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.