PubMed · 4569840
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W H Birkenhäger. 1973-03-17. [Circulation time].. https://pubmed.ncbi.nlm.nih.gov/4569840/
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The red blood cell deformability was determined in 20 children suffering from cystic fibrosis (CF), and the results were compared with the data on 20 healthy children. In CF, a pronounced impairment of the deformability was found.
We measured the frequency distribution of erythrocyte (RBC) transit times in resected lobes of lungs in eight human subjects undergoing thoracotomy for peripheral lung tumors. RBC transit times were measured by the injection of radiolabeled blood flow and volume markers, which were counted in samples from the resected lung. In five of these subjects, the measurements from the resected lung were compared with preoperative measurements of the transit times of radiolabeled RBCs with a gamma camera-computer system. Time-activity curves from the cardiac chambers and the lung or its regions were obtained from which transit times were calculated by the centroid and deconvolution techniques. The reproducibility of transit times measured by this technique was assessed in another eight normal subjects, after sequential bolus injections of radiolabeled cells. The mean transit time of the upper lung region was longer (5.1 +/- 0.5 s) than that of the lower (4.1 +/- 0.6 s, P less than 0.05) in the preoperative study. Similarly, the mean transit time of the upper lung slice was longer (5.5 +/- 0.3 s) than that of the lower slice (3.8 +/- 0.3 s, P less than 0.05) in the resected lung specimens. We conclude that there was good agreement between these techniques and that there are long transit times in the upper regions of human lungs.
A retrospective study of cerebral angiographies from 173 patients with subarachnoid haemorrhage (SAH) were investigated and divided into three groups. The diameters of the middle cerebral artery and the internal carotid artery were measured and correlated with time elapsing between the onset of SAH and the angiographic study. A significant (p less than 0.001) reduction in vascular diameter was found at all levels of intra- as well as extradural parts of the internal carotid artery in patients with aneurysms (group I). Also, bilateral angiographic investigation from 70 patients showed a significant (p less than 0.001) reduction at all levels on both sides, regardless of whether aneurysms were present (group II) or not (group III). Moreover, the reduction in vascular diameter was more pronounced in patients with than in patients without aneurysms. The most pronounced reduction in vascular diameter was found in one of the extradural parts of the internal carotid artery in both group II and III. However, reduction in vascular diameter did not correlate significantly with the cerebral circulation time despite a tendency towards it. On the other hand, layering of the contrast medium along the posterior wall of the internal carotid artery was more often found in patients with prolongation in cerebral circulation time suggesting a reduced cerebral blood flow in these patients. It is suggested that the significant reduction in vascular diameter of intra- as well as extradural parts of the internal carotid artery, might reflect an adaptation to altered cerebral metabolism after SAH.