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Biomedical subjects

M De Roo

Publications and source records attributed to M De Roo.

At least 73 records · Page 4Linked to original sources
PubMed1986

Simple quantitative radioiodination of (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVDU) by exchange labelling.

The synthesis of [125I]-(E)-5-(2-iodovinyl)-2'-deoxyuridine [( 125I]IVDU) by a halogen isotope exchange reaction has been monitored in various reaction conditions. Quantitative incorporation of radioiodine into IVDU was obtained within 20 min by a simple and safe method that is suitable for application in any nuclear medicine laboratory. The radiolabelled antiviral agent can be used without further purification.

Antiviral Agents↗
PubMed1986

Vertebral crush fracture syndrome and reflex sympathetic dystrophy.

The association of reflex sympathetic dystrophy in one or more extremities with vertebral crush fracture syndrome is reported in six cases. In two of them the reflex sympathetic dystrophy preceded the vertebral crush fractures. The 99mTc-methylene diphosphonate scintigraphy results of the skeletons of 42 consecutive patients suffering from vertebral collapse and of 30 matched controls without osteoporosis have been evaluated by three independent observers for abnormal uptakes in the extremities. An abnormal radioactive bone tracer uptake in the extremities has been observed in 15 osteoporotics (36%) and 8 controls (29%). In most cases, osteoporotics and controls, the abnormal uptake was of the zonal type in a localized area, probably reflecting bone remodeling due to localized degenerative changes. An abnormal uptake of the segmental type involving multiple joints and even multiple extremities, as seen in reflex sympathetic dystrophy, was observed in 7 patients of the osteoporotic group (17%) and in none of the control group (P less than 0.05). The patients with an abnormal segmental uptake were younger and had a significantly higher mean 24 h calcium:creatinine ratio as well as a higher urinary hydroxyproline excretion. These observations and results suggest that in some cases of idiopathic osteoporosis there might be a relation between reflex sympathetic dystrophy and vertebral crush fracture syndrome, the vertebral crush fracture syndrome being the axial type of reflex sympathetic dystrophy.

Adult↗
PubMed1986

Increased levels of osteocalcin (serum bone Gla-protein) in rheumatoid arthritis.

Serum osteocalcin was measured by radio-immunoassay in 56 patients with rheumatoid arthritis (RA), and in 50 controls. Mean serum osteocalcin levels were significantly higher in patients with RA. There was a positive correlation between osteocalcin and fasting mucopolysaccharide/creatinine ratio in both sexes, and between osteocalcin and fasting hydroxyproline/creatinine ratio in women. Serum alkaline phosphatase activity, a less specific marker for bone formation, was also increased in RA, and there was a positive correlation with osteocalcin in both sexes. These data suggest that overall bone turnover is increased in RA and that serum osteocalcin may provide additional information for the evaluation of bone metabolism in this disease.

Adult↗
PubMed1986

Scintigraphic evaluation of shape of lung and chest in upright and head-down posture.

We determined the configuration of lungs and chest in six healthy young subjects using anteroposterior and lateral technetium-99m-labeled scintigraphic images obtained in upright and in 90 degree head-down posture at 0, 25, 50, 75, and 100% vital capacity (VC). The lung shape was evaluated from curves relating vertical height vs. cumulative volume of 20 apicodiaphragmatic lung zones of equal height. S-shaped curves were obtained, which, after size normalization, were largely independent of volume or posture (P greater than 0.1). However, the apical zones tended to become relatively wider and the diaphragmatic zones relatively smaller with increasing volume, especially between 0 and 25% VC in upright posture and 0-50% VC in head-down posture. Changing posture from upright to head-down also tended to slightly widen the apical zones and to narrow the diaphragmatic zones, which is in line with a greater intrathoracic penetration of the diaphragm/abdomen. The shape of the chest was evaluated from the ratio of the transverse-thoracic and anteroposterior distances over height. These ratios did not clearly change with posture (P greater than or equal to 0.05) but increased by approximately 30% with decreasing volume (P less than 0.01). The fact that these shape changes of the chest were not accompanied by similar changes in lung shape can be explained mainly by widening of the mediastinum when volume decreases. In conclusion, the shape of the lung and chest are similar in head-down and upright humans, in contrast to the reversal of the apicodiaphragmatic differences in alveolar expansion and in transpulmonary pressure.

Adult↗
PubMed1986

Evaluation of three methods of platelet labelling.

The study of the kinetics of labelled platelets makes sense only when the platelets preserve their viability after separation and labelling. The separation and labelling procedures described in the manual of two producers of 111In-oxinate (Amersham, Mallinckrodt) have been evaluated by in vitro aggregation tests. The method of Mallinckrodt diminished the aggregation capacities of the thrombocytes. The labelled platelets with normal in vitro aggregation response (Amersham) were tested in vivo in 11 patients who underwent peripheral bypass surgery. The platelet half-life and the platelet accumulation on bypass grafts were checked one week post-operatively. Because of the poor in vivo response of both methods (exponential half-life curve and bad graft visualization), a third method was optimized in our laboratory with good in vitro and in vivo results in 12 patients.

Blood Platelets↗
PubMed1986

The use of 131I-meta-iodobenzylguanidine in clinical diagnosis and staging of neuroectodermal tumors. Two case reports.

131I-Meta-iodobenzylguanidine has proved to be useful for the diagnosis of different kinds of neoplasms of neuroectodermal origin. The value of this scintigraphic method as a complementary technic to conventional diagnostic tests for staging in a child with neuroblastoma is described. In another child an ontogenetically related tumor, a mediastinal ganglioneuroma, was also visualized.

3-Iodobenzylguanidine↗
PubMed1985

Diffuse pulmonary uptake of 99mTc bone-imaging agents: case report and survey.

Over the past 5 years, we have encountered 6 cases of diffuse pulmonary uptake of 99m-Tc bone-scanning agents (incidence, 0.04%). To assess the significance of this phenomenon, we reviewed all of the cases reported since 1974 (Including our series, a total of 32 cases). Three groups can be discerned, the first consisting of 24 patients without radiological calcifications in the lungs and with hypercalcemia of different origins (mostly hyperparathyroidism). Of the eight autopsies performed in this group, seven revealed extensive calcifications in alveolar walls and lung vessels; the other autopsy showed no calcification at all and only bronchopneumonic lesions. The second group consists of 6 patients in chronic dialysis. The last group consists of 2 patients having diffuse pulmonary alveolar microlithiasis with extensive radiologic calcifications. The mechanism of lung uptake of 99m-Tc bone-imaging agents is probably the same as that of bone uptake (chemisorption on hydroxyapatite crystals), although other uptake mechanisms have also been discussed. Bone scintigraphy can be useful in the detection of early pulmonary calcifications, which have been associated with impaired pulmonary function and, due to their size, are generally not detected by X-ray.

Adenoma↗
PubMed1985

Single photon emission computerized tomography of the skull.

The diagnostic contribution of single photon emission tomography for detection of bone lesions of the skull was explored in 125 cases and compared with planar imaging. Twenty-one localizations (16% of the total group) were only visualized by scintitomography, these were predominantly lesions of the base of the skull and facial bones. Scintitomography gave a false negative result in only one lesion out of 49 visible on skull radiographs. Together with the revelation of unsuspected bone abnormalities, SPECT generally provides a better visualization of the skull lesions and their extent than does planar imaging. In cases where disease of the facial bones and the base of the skull is suspected, scintitomography is an indispensable adjunct to planar scintigraphy.

Bone Neoplasms↗
PubMed1985

Emergency bypass surgery: late effects on size of infarction and ventricular function.

Using thallium myocardial scintigraphy and radionuclide ventriculography, we assessed size of infarction and left ventricular function at late follow-up (greater than 2 months) in 13 patients who underwent emergency coronary artery bypass surgery (ECABS) during evolving myocardial infarction and in 26 controls who received conventional treatment for acute infarction. Thallium scans were quantitatively analyzed. The thallium defect, expressed as a numerical value in arbitrary units, was smaller after early revascularization (within 4 hr of the onset of symptoms, n = 10) than in the controls: 397 +/- 232 vs 2779 +/- 972 for anterior infarction (p less than .001) and 475 +/- 511 vs 1454 +/- 960 for inferior infarction (p less than .05). The patients undergoing revascularization late (4 to 5 hr after the onset of symptoms, n = 3) had thallium defects comparable to those in the controls. Regional ejection fraction of the involved left ventricular segment was higher after early revascularization (41 +/- 9% vs 21 +/- 8% for anterior infarction, p less than .005; 67 +/- 14% vs 51 +/- 11% for inferior infarction, p less than .01). Global ejection fraction was higher after early revascularization in patients with anterior infarction (57 +/- 10% vs 37 +/- 9%, p less than 0.02), but not in those with inferior infarction (60 +/- 11% vs 54 +/- 8%, p greater than .05). After late revascularization, regional and global ejection fraction were comparable to those in controls. In selected patients, early reperfusion of acutely ischemic myocardium by ECABS can limit size of infarction and preserve left ventricular function, but time constraints may be severe.

Adult↗
PubMed1983

Comparison of scrotal scintigraphy and thermography for the diagnosis of varicocele.

Varicocele is the most frequent cause of male subfertility. Several invasive and noninvasive techniques can be used to visualize scrotal phlebectasies. In this study sequential scintigraphy after intravenous injection of 99mTc-albumin was compared with tele-thermography. The normal and pathological images are described. The more obvious the clinical condition, the more lesions were revealed by scintigraphy (29.6% in subfertile men suspected of having variococele; 76.9% in patients with first degree varicocele; and 100% in Grades II and III cases). In 55 cases (of a total of 76 cases explored by radioisotopic techniques), the comparison of the thermographic results with the scintigraphy results suggests that scrotal scintigraphy is less sensitive. However, there are more false positive thermographies expressed as a discordance with clinical examination, which indicates higher specificity of scintigraphy. In conclusion scrotal scintigraphy cannot be considered as the screening procedure of first choice for varicocele, but it can give complementary information, especially when thermographic results are at variance with the clinical examination.

Diagnostic Errors↗
PubMed1983

Urinary carcinoembryogenic antigen (CEA) in the diagnosis and follow-up of bladder carcinoma.

The level of urinary carcinoembryogenic antigen (CEA) was evaluated in the diagnosis and follow-up of urothelial carcinoma of the bladder. Urinary CEA concentration, cystoscopic findings and the histopathology of an eventually resected bladder tumour were correlated in 177 cases. The sensitivity proved to be 34%, the specificity 82%. Possible correlations with sex, infection, primary tumour or recurrence, differentiation and invasion of an eventually resected tumour and influence of adjuvant therapy were also evaluated. A comparison was made with the results of other authors and different factors which may influence urinary CEA levels are discussed.

Aged↗
PubMed1983

Regional gas distributions and single-breath washout curves in head-down position.

Regional distributions of inspired 133Xe and single-breath washout curves were compared in six young healthy subjects for the upright and the head-down positions. The regional distributions of volumes (at 0, 25, 50, and 75% vital capacity, VC) and of 133Xe boluses inhaled at residual volume (RV) were inverted in the head-down position, thus behaving as if they were determined by gravity acting via the weight of the lung rather than by thoracicoabdominal shape adaptations. Nevertheless no mirror image was obtained. The vertical differences in regional distribution of the 133Xe RV bolus and of the volumes at 25% VC were increased in the head-down position, whereas the vertical difference in volumes at RV was decreased, indicating enhanced air trapping and sequential ventilation at low volumes. This was attributed to the effect of the increased pulmonary blood volume in the head-down posture. Accordingly the size of phase IV on the washout curves with the SF6-bolus as well as with the N2-resident gas method was increased in the head-down position.

Adult↗
PubMed1983

Gravity dependence of phases III, IV, and V in single-breath washout curves.

The gravity dependence of phases III (IIIa and IIIb), IV, and V of simultaneously performed He-bolus and N2-resident gas single-breath washout curves was studied in different body positions by the technique of 180 degrees body inversion between inspiration and expiration. Phase IIIa was mainly determined by nongravitational factors. Phase IIIb was influenced by gravitational, as well as nongravitational, factors. The former were more important with the bolus method in both lateral decubitus positions and the latter with the N2 method in the prone and supine positions. Phases IV and V were mainly gravity dependent. The difference in gravity dependence between the He and N2 methods appeared to be correlated with the vertical interregional concentration gradients of both gases; indeed the vertical gradient was larger for the 133Xe bolus inhaled at residual volume (which is comparable to the He-bolus distribution) than for the 133Xe residual volume-to-total lung capacity ratio (which is comparable to the N2-resident gas distribution). The greater gravity dependence in the lateral decubitus positions than in the supine or prone postures was related to the larger vertical interregional concentration difference as well as to the more pronounced sequential ventilation in the former positions. Finally the negligible effect of gravity on phase IIIa, its moderate effect on phase IIIb, and its predominant effect on phases IV and V were in agreement with the increased sequential filling and emptying due to gravity near residual volume.

Adult↗
PubMed1982

Thyroid function in patients with hyperemesis gravidarum.

An increased free thyroxine (T4) index was observed in 73% of 33 consecutive pregnancies complicated by severe hyperemesis gravidarum. The free triiodothyronine (T3) index was increased in only four of 11 hyperthyroxinemic patients. In five hyperthyroxinemic patients tested, no increase in serum thyrotropin was observed after the injection of thyrotropin-releasing hormone (THR). Goiter, exophthalmos, or previous history of hyperthyroidism was absent in all patients. The thyroxinemia returned to normal in one to several weeks, whether or not it was treated with antithyroid drugs. The thyroid function during the period of hyperemesis had no influence on the subsequent rate of abortion or duration of pregnancy. A lower birth weight, however, was observed in children born to hyperthyroxinemic mothers. Hyperemesis gravidarum should be included in the differential diagnosis of elevations in free T4 index during pregnancy and included in the differential diagnosis of hyperthyroidism.

Abortion, Spontaneous↗
PubMed1982

Comparative study of the sensitivity of CT and quantitative angioscintigraphy in cerebrovascular disease.

A method for multiparametric quantitative cerebral angioscintigraphy is described. For the evaluation of the symmetry of hemispherical bolus transit the following parameters were used: the cumulative L/R hemispheric ratios expressed in arctangent values and the sequential hemispheric activity difference. Both the sensitivity and specificity of this technique for detection of proven stenosis of carotid or cerebral arteries (25 cases) were 80%, in comparison with 60% for computerized axial tomography. A few clinical examples illustrate the diagnostic utility of quantitative cerebral angioscintigraphy. The value of the different quantitative parameters is discussed and compared with other similar studies. With regard to the complementary role of computerized axial tomography and serial cerebral scintigraphy the results of other authors were confirmed. Considering the broad field of application for dynamic brain scintigraphy and the fact that both sensitivity and specificity of this exploration are comparable to, or even better than, CT, it is our opinion that isotopic exploration remains a reliable detection method for cerebrovascular disease.

Cerebral Infarction↗