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Biomedical subjects

B Bok

Publications and source records attributed to B Bok.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Microautoradiographic method permitting the study of migration of 99m-technetium labelled leukocytes].

Cell migration studies are very important in inflammatory phenomena. Methods currently used are not quantitative and have been subject to much controversy. Homogeneity of 99mTc leukocyte labelling was verified by a microautoradiographic method (MAR), which was performed in our laboratory. This method was used in cell migration studies to verify if the migrating cells were indeed the labelled cells.

Autoradiography↗
PubMed1984

Technetium 99m autoradiography of labelled white cells.

The cellular uptake of technetium 99m was determined on white blood cells (WBC) by autoradiography, after 'cold' tin pyrophosphate prelabelling followed by pertechnetate labelling. The autoradiographic method gave visible tracks of 99mTc internal conversion and Auger electrons. 75 +/- 5% of the treated WBC were labelled but none of the control WBC. The number and length of tracks per cell varied greatly. This was perhaps due to imaging conditions as well as to variations in cell uptake.

Autoradiography↗
PubMed1984

99m Technetium labelled heparin: potential value as a tracer of heparin activity in pharmacokinetic and biodistribution studies.

Pharmacokinetics and biodistribution of 99m Technetium (99mTc) labelled heparin were studies to assess its value as a tracer of heparin kinetics in comparison with unlabelled heparin. In vitro, the stability and labelling efficiency (98%) of the labelled drug were excellent and elution was minimal. In vivo, after I.V. infusion of the drug, there was no difference in the same animal between anticoagulant activity measurements and radioactive countings, both displaying a plasmatic biexponential pattern (T1 = 2.9 minutes, T2 = 76 minutes). Biodistribution studies showed primarily liver, spleen and kidney accumulation, with no thyroid uptake. The advantages of this technetium labelling may therefore be used for the heparin drug in various experimental and pathological situations even in humans.

Animals↗
PubMed1983

Bone scintigraphy in Perthes disease.

After intravenous injection of 99mTc methyldiphosphonate, 190 hip bone scans were performed on 103 children. In 64 children with Perthes disease, 61 of 71 hips (86%) showed abnormal scintigraphy. There were no false positives. In other hip disorders, the scan was never considered to simulate Perthes disease. There were 36 children with acute synovitis and three with Meyer's dysplasia. The sensitivity was 97%, suggesting that this test should be used more frequently in the early assessment of hip pain in the young child, before the appearance of characteristic radiographic abnormalities. This test is also valuable for follow-up of the disease because of its prognostic value--the bone scan becomes normal far earlier than the radiograph. The progressive normalization of the scan may help determine when the child can begin weight-bearing.

Adolescent↗
PubMed1983

Five leucocyte labelling techniques: a comparative in-vitro study.

During the past years, several authors have used labelled leucocytes to detect inflammatory foci. However, before routine use in man. It is necessary to control the viability of labelled cells. Five leucocyte labelling techniques (111In-oxine, 111In-oxine without extraction, 99mTc oxine, pyrophosphate 99mTc, 51Cr) were compared using the same separation methods, conservation medium, viability assays and migration studies. Electron microscopic studies allowed the assessment of cellular damage induced by the labelling techniques as well as the calculation of the percentage of cells disrupted during preparation. Results obtained in vitro using 111In-oxine were not satisfactory and in fact appeared contradictory to those published by the authors using this technique in vivo. Even the best method, pyrophosphate 99mTc labelling, was not completely atoxic, but the functional behaviour of the leucocytes did not seem affected. While in vitro studies offer much information concerning labelled cells, they cannot predict the in vivo behaviour of these cells.

Chemotaxis, Leukocyte↗
PubMed1982

Bone scintigraphy in the diagnosis and follow up of Perthes' disease.

One hundred and thirty three children were studied (a total of 218 scintigrams) after IV injection of 100 microCi/kg 99Tc-MDP. Of 64 pathological hips (6 being bilateral), 52 were judged typically abnormal, 8 without initial radiological evidence. Of the rest, 8 were considered doubtful and 4 normal. No scan was considered typical of Perthes' disease in other hip disorders. The resulting figure of the sensitivity was 94%, for specificity 97%, for positive predictive value 97%, and for negative predictive value 95%. It is more difficult to assess the value of bone scintigraphy in the follow up of these patients. The disappearance of uptake defect in the femoral head may be a good index and occurs earlier than the normalization of the radiographs. On the other hand, the significance of the neighbouring region of increased uptake is difficult to assess although related to revascularization and reconstruction. The evolution of the disease does not seem to be correlated with the localization and the intensity of these regions in a straightforward manner.

Adolescent↗
PubMed1980

99mTc labelled human leukocytes. An in vitro functional study.

A new method of human leukocyte labelling is described. 20 ml of human blood are allowed to sediment in a dextran solution and the remaining red blood cells are removed using NH4C1. The leukocyte-rich suspension is incubated with a Sn-pyrophosphate solution, and then labelled, using 20 mCi 99mTc pertechnetate. Labelling efficiency is about 30%. Functional activity was shown to be satisfactory: (1) appearance under electron microscopy was quite normal; (2) Klebsiella ingestion, zymosan-stimulated oxygen consumption and iodination were similar in labelled and unlabelled cells, and (3) chemotaxis revealed no alteration in cell migration.

Cell Separation↗
PubMed1980

[Serum gastrin: interests and limitations of radio-immunoassay (author's transl)].

Radio-immunoassay of serum gastrin may now be carried out in all laboratories of radio-immunology. Comparison of two commercial kits A: Schwartz-Mann and B: CEA-SORIN according to criteria of specificity, sensitivity and reproducibility within and between systems, shows that they both permit the detection of pathological hypergastrinemias (Zollinger Ellison and atropic gastritis). Both kits have an identical intra-system coefficient of variation (10 p. cent and 7 p. cent for A, 5 p. cent and 8 p. cent for B) on the other hand, the inter-system coefficient of variation is better for kit B (22,4 p. cent and 37 p. cent for kit A, and 11,5 p. cent and 14,2 p. cent for kit B). The normal values for each kit are quite different: 97 + 64 pg.ml-1 for A and 51 . 23 pg.ml-1 for B preventing one from comparing estimations carried out with two different kits.

Adenoma↗
PubMed1980

"In vivo" kinetics of 99m-technetium labelled leucocytes in dogs and the effects of an abscess.

A new labelling method of blood white cells using "cold" pyrophosphate and 99m-technetium pertechnetate was assessed in 6 normal dogs and 6 dogs with turpentine induced abscesses (8). In normal dogs, blood kinetic studies showed a two component exponential disappearance pattern of the radioactivity, the late half-life being from 4 to 20 hours. Direct organ counting and external computer assisted gamma camera counting showed an immediate accumulation in the lungs followed by a progressive decrease. There is a marked uptake into the liver and spleen. In bearing abscesses dogs, there is an obvious increase in local radioactivity, in spite of a decreased local blood supply, allowing scintigraphic demonstration of such foci in a limb. However, the abscess model is far from perfect and further studies are required before there is a routine use in man for the detection of abscesses.

Abscess↗
PubMed1979

[Contribution of scintigraphy in non-infectious hip diseases in children].

Radioisotopic examination in children's hip disorders permits an approach to vascular pathology, useful in establishing both diagnosis and prognosis. In this paper, particular attention is devoted to Legg-Calvé-Perthes disease, because of the gravity of the sequellae encountered. Acute transient synovitis and its relation to the preceding affection is briefly discussed. Lastly, Meyer's dysplasia, whose pathogenesis is still not certain, is mentioned. An attempt is made to deduce a practical therapeutic attitude.

Bone Diseases, Developmental↗
PubMed1978

A new unidirectional moving whole body scanner: comparative study of performances.

A new whole-body unidirectional moving scanner was built using a single large bar crystal, 12 photomultipliers on its top, and a delay line system to compute the X coordinate. Motion is required in only one direction on the Y-axis, and a special collimation is adapted in order to equal the X and Y performances of the detector. The performances of this detector (C.G.R. Scanicamera) (SC) were compared under the same conditions with those of a moving rectilinear scanner (R.S.) (Ohio Nuclear F 84 dual-head scanner, 12.5 cm crystal) and with an Anger gammacamera equipped with its whole body attachment (W.B.C.) Nuclear Chicago Pho Gamma III H.P.). The general impression is that this new whole-body unidirectional moving scanner is a very convenient device for whole body studies and can also be used for large scintigraphies.

Adult↗
PubMed1978

Jugular venous reflux in cerebral radionuclide angiography: an explanation.

A case of isotopic jugular venous reflux, reaching the opposite jugular vein, is described. Phlebography and aortography were simultaneously performed in this patient and showed the innominate vein narrowed and pinched between the sternal notch and the aortic arch. This narrowing depends on the position of the left arm.

Aged↗