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Biomedical subjects

M R Hardeman

Publications and source records attributed to M R Hardeman.

46 records · Page 3Linked to original sources
PubMed1981

111Indium-labelled leucocyte scintigraphy in the diagnosis of inflammatory disease--first results.

In 61 patients, 66 scans were performed with 111In-labelled autologous leucocytes to evaluate this method in the diagnosis of inflammatory disease. All scintigraphic results were compared with clinical, operative or postmortem findings. In the first 20 examinations in 19 patients, 2 scintigrams were true positive, 9 true negative one of false positive, whereas 9 scintigrams had to be considered as false negative. These false negative results were probably due to loss of viability of the labelled cells. A modified labelling technique, in which a much lower concentration of oxine was used, was employed for a further 46 examinations in 42 patients. Twenty-four scintigrams were true positive and 22 true negative, while no false positive or false negative results were observed. These results suggest that this modified technique is useful in the diagnosis of inflammatory disease.

Abdomen↗
PubMed1980

Comparison of indium-111 oxinate labelled autologous granulocytes with indium-111 oxinate and indium-111 chloride as abscess scanning agents. An experimental study in an animal model.

Bacterial abscesses were evoked in goats. Imaging of these abscesses was obtained by means of labelling autologous granulocytes with 111In oxinate, reinjection of the cells into the animal, and scintigraphy by gamma camera one day later. Comparable imaging results, however, were obtained after intravenous injection of 111In oxinate or of 111In chloride. The gamma camera images were supported by tissue distribution studies. In the case of administration of 111In oxinate to the goats, the radioactivity accumulated in the cell fraction of the blood to a significant extent. This did not occur in the case of plain 111In chloride. It remained unexplained why such different accumulation in cells did not result in differences in the scintigraphic studies. Blood clearance studies supplied conclusive evidence that the granulocytes stayed in the circulation for several days following labelling with 111In oxinate and reinjection of the cells into the animals.

Abscess↗
PubMed1975

Serotonin uptake and glycolytic activity of human platelets after prolonged incubation with glucose-poor plasma.

It is confirmed that metabolic energy is a prerequisite for the uptake of serotonin by human blood platelets. Starvation (i.e. incubation at 25 degrees C of platelets resuspended in glucose-poor autologous plasma) generally stops glucose consumption, lactate formation as well as serotonin uptake within 2 h. The addition of glucose restores lactate formation immediately and, independent of total starvation time, to normal or even higher levels. The active uptake of serotonin, however, can be restored only partly after prolonged incubation with glucose, to an extent which seems to be dependent of the preceding starvation time. The results are compatible with the hypothesis that besides an active carbohydrate metabolism another factor, presumably the integrity of the platelet membrane, is obligatory for the active transport of serotonin.

Biological Transport↗
PubMedDate not supplied

Analyzing red blood cell-deformability distributions.

BACKGROUND: Red blood cells (RBCs) must deform to pass the smallest capillaries of the microcirculation. Available techniques for measuring RBC deformability often provide an indication of the mean deformability. The latter may be decreased either by a slight overall deformability reduction or by the presence of a small fraction of rigid cells. A distinction between these two cases can be made with a RBC-deformability distribution (RBC-DD). METHODS: This paper explores RBC-DDs of healthy individuals and of cells with anomalous mechanical properties (sickle cell disease, dialysis patients, elliptocytosis, and cultivated malaria tropica). The distributions were measured with an automated rheoscope, which uses advanced image analysis techniques to obtain the deformability index of a large number of individual cells subjected to simple shear flow. RESULTS: The RBC-DD of healthy volunteers is close to a normal distribution. In the investigated patients, distributions were markedly different and yielded significant changes in the mean, in the standard deviation, or in both. The presence of hypodeformable and hyperdeformable cell fractions can qualitatively and quantitatively be assessed from the deformability distribution (DD). In elliptocytosis, cells orient differently with respect to the streamlines, compared to normal cells. This causes the DD to be biased. CONCLUSIONS: The RBC-DD is a powerful representation to establish subpopulations with anomalous deformability. Fractions of hypodeformable and hyperdeformable cells and the standard deviation of the DD are new and excellent quantitative parameters to assess alterations in RBC deformability.

Anemia, Sickle Cell↗
PubMedDate not supplied

The effect of continuous dialysis on platelet preservation.

Serotonin uptake and response to hypotonic shock were studied after storage of platelet-rich plasma for three days at 4, 25, and 37 C. Both properties were best maintained at 25 C. The greatly impaired serotonin uptake and hypotonic shock response of platelets stored for three days at 37 C were partly restored by resuspension of the platelets in fresh autologous plasma. No improvement was found when platelets stored at 4 C were resuspended in fresh autologous plasma. When platelet suspensions were stored for three days at 4, 25, and 37 C under continuous dialysis against plasma, the results obtained at 37 C were even better than those obtained with platelets stored at 25 C. These results indicate that if the accumulation of metabolites in the plasma milieu, which in addition to other changes results in a drop of pH, is prevented, the effective storage time of platelet concentrates can be prolonged. The use of a closed plastic dialysis system, based on the triple-bag transfusion set is suggested.

Blood Platelets↗
PubMedDate not supplied

Conductance method for the measurement of cross-sectional areas of the aorta.

A modified conductance method to determine the cross-sectional areas (CSAs) of arteries in piglets was evaluated in vivo. The method utilized a conductance catheter having four electrodes. Between the outer electrodes an alternating current was applied and between the inner electrodes the induced voltage difference was measured and converted into a conductance. CSA was determined from measured conductance minus parallel conductance, which is the conductance of the tissues surrounding the vessel times the length between the measuring electrodes of the conductance catheter divided by the conductivity of blood. The parallel conductance was determined by injecting hypertonic saline to change blood conductivity. The conductivity of blood was calculated from temperature and hematocrit and corrected for maximal deformation and changes in orientation of the erythrocytes under shear stress conditions. The equations to calculate the conductivity of blood were obtained from in vitro experiments. In vivo average aortic CSAs. determined with the conductance method CSA(G) in five piglets, were compared to those determined with the intravascular ultrasound method CSA(IVUS). The regression equation between both values was CSA(G)=-0.09+1.00 x CSA(IVUS), r=0.97, n=53. The mean difference between the values was -0.29%+/-5.57% (2 standard deviations). We conclude that the modified conductance method is a reliable technique to estimate the average cross-sectional areas of the aorta in piglets.

Animals↗